Working Report 2007-92
Geological Model of the Olkiluoto Site Version 1.0
Jussi Mattila, Ismo Aaltonen Kimmo Kemppainen, Liisa Wikström Markku Paananen, Seppo Paulamäki Kai Front Seppo Gehör, Aulis Kärki Turo Ahokas
January 2008
POSIVA OY FI-27160 OLKILUOTO, FINLAND Tel +358-2-8372 31 Fax +358-2-8372 3709 Working Report 2007-92
Geological Model of the Olkiluoto Site Version 1.0
Jussi Mattila, Ismo Aaltonen, Kimmo Kemppainen, Liisa Wikström Posiva Oy
Markku Paananen, Seppo Paulamäki Geological Survey of Finland
Kai Front Technical Research Centre of Finland
Seppo Gehör, Aulis Kärki Kivitieto Oy
Turo Ahokas Pöyry Environment Oy
January 2008
Base maps: ©National Land Survey, permission 41/MYY/08
Working Reports contain information on work in progress or pending completion. ABSTRACT
The rocks of Olkiluoto can be divided into two major classes: 1) supracrustal high-grade metamorphic rocks including various migmatitic gneisses, tonalitic-granodioritic- granitic gneisses, mica gneisses, quartz gneisses and mafic gneisses, and 2) igneous rocks including pegmatitic granites and diabase dykes. The migmatitic gneisses can further be divided into three subgroups in terms of the type of migmatite structure: veined gneisses, stromatic gneisses and diatexitic gneisses. On the basis of refolding and crosscutting relationships, the metamorphic supracrustal rocks have been subjected to polyphased ductile deformation, consisting of five stages, the D2 being locally the most intensive phase, producing thrust-related folding, strong migmatisation and pervasive foliation.
In 3D modelling of the lithological units, an assumption has been made, on the basis of measurements in the outcrops, investigation trenches and drill cores, that the pervasive, composite foliation produced as a result of polyphase ductile deformation has a rather constant attitude in the ONKALO area. Consequently, the strike and dip of the foliation has been used as a tool, through which the lithologies have been correlated between the drillholes and from the surface to the drillholes.
The bedrock at the Olkiluoto site has been subjected to extensive hydrothermal alteration, which has taken place at reasonably low temperature conditions, the estimated temperature interval being from slightly over 300oC to less than 100oC. Two types of alteration can be observed: 1) pervasive (disseminated) alteration and 2) fracture-controlled (veinlet) alteration. Kaolinisation and sulphidisation are the most prominent alteration events in the site area. Sulphides are located in the uppermost part of the model volume following roughly the lithological trend (slightly dipping to the SE). Kaolinite is also located in the uppermost part, but the orientation is opposite to the main lithological trend (slightly dipping to the N). The third main alteration event, illitisation, consists of two distinct volumes, which lie one on the other and converge in the northwest, and are spatially associated with site-scale thrust faults.
The fault zones at Olkiluoto are mainly SE-dipping thrust faults formed during contraction in the last stages of the Fennian orogeny, approximately at 1800 Ma ago and were reactivated in several deformation phases, as indicated by fault-slip data and K-Ar age determinations. In addition, NE-SW striking strike-slip faults are also common. Fault zone intersections from drillholes, the ONKALO access tunnel and outcrops have been correlated by the application of slickensides orientations, mise-à-la-masse- measurements, eletctromagnetic soundings, 3D seismics and VSP-reflectors, resulting in six site-scale and 84 local-scale fault zones.
Keywords: lithology, ductile deformation, brittle deformation, hydrothermal alteration, 3D modelling, nuclear waste disposal, Olkiluoto, Eurajoki, Finland. Olkiluodon alueen geologinen malli. Versio 1.0
TIIVISTELMÄ
Olkiluodon kivilajit voidaan jakaa kahteen pääluokkaan: 1) suprakrustiset, korkean metamorfoosiasteen kivet, jotka ovat erilaisia migmatiittisia gneissejä, tonaliitti- granodioriitti-graniittigneissejä, kiillegneissejä, kvartsigneissejä ja mafisia gneissejä, 2) magmakivet, jotka ovat pegmatiittisia graniitteja ja metadiabaaseja. Migmattiittiset gneissit voidaan edelleen jakaa kolmeen alaryhmään migmaattirakenteen perusteella: suonigneissit, raitaiset gneissit ja diateksiittiset gneissit. Uudelleenpoimutus- ja leik- kaussuhteiden perusteella metamorfiset kivet ovat käyneet läpi viisivaiheisen duktiilin deformaation, joista D2-vaihe on intensiivisin ja jonka aikana muodostui ylityöntöön liittyvää poimutusta, voimakasta migmatisaatiota sekä alueella havaittava läpikotainen liuskeisuus.
Litologisten yksiköiden 3D-mallinnuksessa on maanpinta- ja kairanreikähavaintojen perusteella oletettu, että monivaiheisessa duktiilideformaatiossa syntyneellä läpiko- taisella liuskeisuudella melko pysyvä suuntautuneisuus tutkimusalueella. Tämän perus- teella liuskeisuuden suuntaa ja kaltevuutta on voitu käyttää työkaluna, jolla litologisia yksiköitä on korreloitu kairanreikien välillä ja maanpinnalta kairanreikään.
Olkiluodon kallioperässä on vaikuttanut laajamittainen hydroterminen muuttuminen, mikä on tapahtunut melko alhaisessa lämpötilassa (300 - 100oC). Muuttuminen jakaan- tuu kahteen päätyyppiin: 1) läpikotainen muuttuminen ja 2) suoniverkostotyyppinen tai rakoilun kontrolloima muuttuminen. Kaoliniittiutuminen ja kiisuuntuminen ovat merkittävimmät muuttumiset. Muuttumisen kolmas päätyyppi, illiittiytyminen, muodos- taa kaksi toistensa päällä sijaitsevaa tilavuutta, jotka yhdistyvät mallinnetun alueen luoteisosassa. Illitisaatio liittyy mallinnetun alueen ylityöntösiirroksiin.
Olkiluodon alueen siirrokset ovat pääasiassa kaakkoon kaatuvia ylityöntösiirroksia, jotka muodostuivat Fennisen vuorijononmuodostuksen loppuvaiheessa, noin 1800 Ma sitten; siirrosanalyysin ja K-Ar-ikämääritysten perusteella vyöhykkeet ovat aktivoi- tuneet useasti eri deformaatiovaiheissa. Ylityöntösiirrosten lisäksi lounas-koillinen suuntaiset strike-slip siirrokset ovat alueella yleisiä. Siirrosvyöhykelävistyksiä kairarei’istä on mallinnettu käyttämällä hyväksi haarniskapintaisten rakojen suuntia, latauspotentiaalimittauksia, sähkömagneettisia luotauksia, 3D-seismiikkaa sekä VSP- heijastajia. Alueelle on mallinnettu yhteensä kuusi alueellista ja 84 paikallista siirros- vyöhykettä.
Asiasanat: litologia, duktiili deformaatio, hauras deformaatio, hydroterminen muuttuminen, 3D-mallinnus, ydinjätteiden loppusijoitus, Olkiluoto, Eurajoki. 1
TABLE OF CONTENTS
ABSTRACT
TIIVISTELMÄ
PREFACE...... 3
1 INTRODUCTION ...... 5 1.1 Background...... 5 1.2 Report objectives and relation to previous versions ...... 5 1.3 Structure of this report ...... 8
2 DATA SOURCES AND EVALUATION OF DATABASE ...... 9 2.1 Overview ...... 9 2.2 Surface-based geological investigations...... 11 2.2.1 Surface data...... 11 2.2.2 Drillhole data ...... 13 2.3 Surface-based geophysical investigations...... 18 2.3.1 Airborne and ground surveys ...... 18 2.3.2 Drillhole logging and drillhole-based surveys...... 20 2.4 Underground investigations...... 22 2.4.1 Tunnel mapping...... 22 2.4.2 Pilot drillholes...... 27 2.4.3 Analogue studies – VLJ access tunnel and repository...... 28 2.5 Other sources of data ...... 29 2.6 Feedback from other disciplines, the integrated ONKALO area model and prediction-outcome studies...... 30
3 GEOLOGICAL EVOLUTION OF THE BEDROCK...... 37 3.1 Overview to the geology of Finland...... 37 3.2 Regional geology...... 39 3.2.1 Palaeoproterozoic lithology...... 39 3.2.2 Deformation and metamorphism...... 39 3.2.3 Palaeoproterozoic tectonic evolution ...... 42 3.2.4 Later events not related to orogeny/orogenies...... 43 3.3 Local geology...... 45 3.3.1 Lithological relations...... 45 3.3.2 Ductile deformation...... 55 3.3.3 Brittle deformation ...... 70 3.3.4 Alteration ...... 77 3.3.5 Synopsis...... 81
4 GEOLOGICAL MODEL...... 83 4.1 General principles and overview...... 83 4.2 Lithological model...... 87 4.2.1 Conceptual model...... 87 4.2.2 Modelling assumptions and methods...... 88 4.2.3 Spatial model...... 94 4.2.4 Evaluation of uncertainties ...... 112 4.3 Ductile deformation model ...... 115 4.3.1 Conceptual model...... 115 2
4.3.2 Modelling assumptions and methods...... 116 4.3.3 Spatial model...... 119 4.3.4 Evaluation of uncertainties ...... 119 4.4 Hydrothermal alteration model...... 122 4.4.1 Conceptual model...... 122 4.4.2 Modelling assumptions and methods...... 124 4.4.3 Spatial model...... 127 4.4.4 Evaluation of uncertainties ...... 140 4.5 Brittle deformation model ...... 143 4.5.1 Conceptual model...... 145 4.5.2 Modelling assumptions and methods – fault zones ...... 150 4.5.3 Spatial model...... 166 4.5.4 Evaluation of uncertainties ...... 190 4.6 Selected fracture statistics ...... 194 4.6.1 Overview and data sources...... 194 4.6.2 Methods ...... 195 4.6.3 Results ...... 197 4.7 Integrated assessment of different 3D submodels and disciplines ...... 229 4.7.1 Lithology and brittle deformation model ...... 229 4.7.2 Alteration and brittle deformation model ...... 230 4.7.3 GPS measurements and brittle deformation zones ...... 232 4.7.4 Microseismicity and brittle deformation zones ...... 234
5 CONFIDENCE ASSESSMENT...... 239 5.1 Data resolution...... 239 5.2 Main uncertainties...... 242 5.2.1 Lithological model...... 242 5.2.2 Ductile deformation model ...... 243 5.2.3 Alteration model...... 243 5.2.4 Brittle deformation model ...... 243 5.3 Main issues...... 244
6 SUMMARY ...... 247
REFERENCES ...... 251
APPENDICES...... 275 3
PREFACE
The geological model of the Olkiluoto site area has been produced by the Geological Modelling Task Force (GeoMTF), a team of geology and geophysics experts established by Posiva to carry out geological modelling of Olkiluoto. The following members of the GeoMTF have contributed to the modelling work: Kai Front (Technical Research Centre of Finland, VTT), Aulis Kärki and Seppo Gehör (Kivitieto Oy), Markku Paananen and Seppo Paulamäki (Geological Survey of Finland, GTK), Turo Ahokas (Pöyry Environment Oy) and Ismo Aaltonen, Kimmo Kemppainen, Jussi Mattila and Liisa Wikström (Posiva Oy). Jussi Mattila has edited the report.
The report has been reviewed by Professor Alan Geoffrey Milnes (GEA Consulting), Prof. Dr. Cees W. Passchier (CeeTecs), Professor John A. Hudson (Rock Engineering Consultants), Professor Krister Sundblad (University of Turku), Professor Olav Eklund (University of Turku), Dr. Timo Kilpeläinen (University of Turku), Dr. Raymond Munier (SKB), Dr. Johan Andersson (JA Streamflow AB), Mrs. Pirjo Hellä (Pöyry Environment Oy) and Mr. Lasse Koskinen (Posiva Oy). The authors wish to thank them all for their valuable comments and suggestions. Christopher Cunliffe is thanked for corrections to the English of the text. 4 5
1 INTRODUCTION
1.1 Background
In Finland, two companies, Teollisuuden Voima Oy (TVO) and Fortum Power and Heat Oy (formerly Imatran Voima Oy), utilise nuclear energy to generate electric power. The companies are preparing for the final disposal of the spent nuclear fuel waste deep in the bedrock. In 1996, they established a joint company, Posiva Oy, to run the programme of site suitability investigations and other research and development for spent fuel disposal. Posiva will ultimately construct and operate the future disposal facility. After an extensive investigation programme had been carried out at several sites since 1987, Posiva submitted an application to the Government in May 1999 for a Decision-in- Principle to build a final disposal facility for spent fuel at Olkiluoto, in the municipality of Eurajoki, on the west coast of Finland. The Decision-in-Principle was approved by the Finnish Parliament in 2001, allowing Posiva to continue the development of a repository in the bedrock at Olkiluoto. Construction of the repository is planned to start around 2015, and the final disposal facility should commence operations in 2020 (Tanskanen & Palmu 2003). As a part of the site investigations, an underground rock characterisation facility, ONKALO, is being constructed at Olkiluoto during 2004-2010. The aim of ONKALO is to study the bedrock of the site for the planning of the repository and for the safety assessment, and to test the disposal techniques in real deep- seated conditions. At a later date, it may become part of the repository. ONKALO will be composed of characterisation facilities, connected to the surface by an access tunnel and a ventilation shaft. Its construction will begin with excavation an access tunnel, approximately 5.5 km in length, to the depth of 520 m. The main characterisation level of ONKALO will be at the depth of 420 m. Excavation of the ONKALO access tunnel started in autumn 2004 and has now reached a chainage of about 2000 m (depth ca. 200 m).
1.2 Report objectives and relation to previous versions
The main objective of the present report is to update and revise the Geological Site Model of Olkiluoto (Version 0, Paulamäki et al. 2006), made necessary by the further processing of existing and the acquisition of new geological data from the Olkiluoto area. The purpose of the Geological Site Model is to evaluate the geological properties and conditions of the rock mass in the Olkiluoto Site area and as such the model provides the geometrical framework and the geoscientific descriptions necessary for the development of the site-scale rock mechanics, hydrogeological and (hydro)geochemical models, which are required for simulating the behaviour of the surroundings of the repository in the short and long term, i.e. for the design and construction of the repository and for the demonstration of safety (Figure 1-1). 6
Figure 1-1. Flow chart of the interaction between the geological model and other disciplines.
The bedrock volume which is considered in the GSM lies beneath a square segment of Olkiluoto island and some small marine areas which are named the Olkiluoto Site Area. The location and coordinates of the Site Area are shown on Figure 1-2. The lower surface of the GSM model volume lies at the depth of 1000 metres and most of the deep drillholes and the whole of the ONKALO facility lie within this model volume (Figure 1-3). The GSM combines the results of geological surface mapping, drillcore studies and tunnel mapping, with interpretations of geophysical data from airborne and ground surveys, and geophysical drillhole measurements. In comparison to the GSM version 0 (Paulamäki et al. 2006), the GSM version 1 (this report) is based on an expanded data base from geological surface mapping, and on results from the logging of ten new deep drillholes and the mapping of about 1000 metres more of the ONKALO access tunnel (with several pilot drillholes and corresponding prediction/outcome studies). In addition, a number of new geophysical surveys have been carried out since the GSM version 0 modelling. It should be noted that the GSM activities run parallel with activities related to modelling of a much smaller model volume, whose upper surface is represented by the ONKALO area (see Figure 1-2). The aim of the ONKALO model, which essentially contains the ONKALO access tunnel and will contain the future ONKALO rock characterisation facility, is to support the rock engineering effort and provide rock mechanics and hydrogeological predictions as tunnelling proceeds. Two versions of the ONKALO model have so far been published, Paananen et al. (2006) and Kemppainen et al. (2007). These have been used as an important background for the present report, while concentrating more on geological characterisation and site understanding. 7
Figure 1-2. Nominal model areas of Olkiluoto, showing the location of the Olkiluoto Site Area (which is the top surface of the rock volume and is the subject of this report, see Figure 1-3). 8
Figure 1-3. A 3D view of Olkiluoto island showing the model volume of the Geological Site Model, its top surface given by the ground surface (the Site Area shown on Figure 1-2, with corner coordinates) and its bottom surface by a horizontal plane at a depth of 1000 metres (Z = -1000). The deep drillholes which have been drilled at the site and the planned ONKALO access tunnel are shown within the model volume.
1.3 Structure of this report
The present report is subdivided into 6 consecutive chapters, covering (2) description of data sources applied for the present model, evaluation of the data and also feedback received from other disciplines (hydrology, hydrogeochemistry, rock mechanics and long-term safety) and from the recently released ONKALO area model (Kemppainen et al. 2007), (3) compilation of the status of present knowledge on the geological evolution of the Olkiluoto area and surrounding regions, arranged into thematic subsections, (4) detailed description of the current model on a thematic basis, i.e. the chapter is subdivided into 7 sections, the first one giving an overview of the model, sections two to four describing the assumptions and methodologies, and uncertainties for the lithological, ductile deformation, alteration and brittle deformation models, respectively, section 6 covering the characteristic of the fracturing at the site and section 7 compiling the thematic submodels into an integrated approach and assessing their internal consistency, (5) confidence assessment of the present model and an evaluation of the main uncertainties and main future activities, and (6) summary of the report. Appendices are listed at the end of this report. 9
2 DATA SOURCES AND EVALUATION OF DATABASE
2.1 Overview
This chapter provides a brief overview of the data used for constructing the present geological model. The aim is to provide traceable references to the data sources and to evaluate the database, not to present the actual data. Specific guidelines for the collection of geological data is given in the Geological Data Acquisition report (Milnes et al. 2007), in which the different levels of investigations and data sources have been categorised according to the scheme shown in Table 2-1. The sources of data are subdivided according to whether it has been collected by using a system of linear sampling (core, drillhole and scanline logging), by mapping bedrock exposures which are essentially planar and two-dimensional in form (natural or cleared bedrock outcrops, quarry walls, road cuts, etc.), or by mapping in situations where the bedrock exposures allow something approaching a 3D view of the geological structures (particularly tunnel mapping). These are data sources A, B and C, respectively (Table 2-1). Since the aim of deterministic geological modelling is to build up a 3D model of the underground relationships, it is clear that this sequence is also a sequence of increasing data confidence. Although the table is mainly focused on the classification of geological data, in the present report the system has also been applied to geophysical data.
The categorisation of level of investigation is intended to give a qualitative idea of how reliable, complete and/or systematically collected the data is judged to be (Table 2-1). Level 1 data sets have been acquired using general or unsystematic mapping and logging techniques, at a level of detail which make them unsuitable for statistical processing. Level 1 can be called the general level, and for many applications, such data is perfectly adequate, and sometimes of critical importance (for instance, in the "observational method" of underground rock engineering). Also, it should be emphasised that general geological mapping, which is placed in this category, represents a long tradition and a high level of expertise, and includes almost all the data collected for increasing site understanding, which is an essential element in geological modelling. Level 2 data sets consist of systematically collected data, which satisfy the requirements of statistical treatment, after suitable corrections for sampling bias and other distortions have been made. This level can be called the systematic level of site investigation and is usually carried out with a particular aim in mind, e.g. to be used as a basis for DFN (Discrete Fracture Network) modelling or rock quality assessment. Different types of systematic investigation are planned in order to satisfy the needs for statistically sound data for various purposes, both on rock cores, surface outcrops and tunnel walls, as indicated in Table 2-1. Level 3 represents the research level of investigation, which is necessary in order to address problems, which arise during the site investigation due to conditions, that are unusual in a nuclear waste disposal context. At Olkiluoto, this refers particularly to the heterogeneity and anisotropy of the widespread migmatites and the relation between these and the fracturing, which cannot be addressed using the experience gathered in other nuclear waste disposal programmes. On the other hand, a research programme has to be developed separately from the investigations at the general and systematic levels, to allow for new ideas and techniques to be developed and tested.
In the following sections, the data used in the construction of the present geological model has been subdivided into “Surface-based geological investigations” (Section 2.2), 10
“Surface-based geophysical investigations” (Section 2.3) and “Underground investigations” (Section 2.4). Each reference has been classified according to the categories presented in Table 2-1, where applicable. Although Table 2-1 is useful for evaluating the database in most cases, there are some activities which cannot be addressed in this way, but which provide important background material, for instance, for increasing site understanding. These are classified under the general category “Other sources of data” and are discussed in Section 2.5. Finally, Section 2.6 gives an overview of the feedback received from other disciplines and the recently published integrated ONKALO-area model (Kemppainen et al. 2007) since the publication of the last geological site model (Paulamäki et al. 2006).
Table 2-1. Overview of sources of geological data and levels of investigation. The classification of data types refers to the logging and mapping procedures most relevant to the acquisition of geological data for modelling at the Site and ONKALO scales.
LEVELS OF INVESTIGATION General level of Systematic level of Research level of investigation investigation investigation (Level 1) (Level 2) (Level 3) general mapping and collection of systematic special studies of logging procedures for data for statistical research nature needed SOURCES overall understanding of processing, particularly because of site-specific OF DATA site geology or for rapid as a background for conditions at Olkiluoto assessment of rock engineering and construction-related hydrogeological parameters modelling Data source A A1-type data A2-type data A3-type data "Linear sampling" (core e.g general logging of e.g. detailed logging of e.g. special study of and scanline logging, oriented core at the oriented core and OPTV research nature based on ref. scale ca. l m) drilling site; "quick in the core archive; detailed look" scanline logging; detailed logging of logging/sampling of engineering geological OPTV images from core segments, detailed logging of unoriented or uncored boreholes; scanline logging, etc., partly oriented core. normal scanline logging with supporting laboratory studies Data source B B1-type data B2-type data B3-type data "Areal sampling" e.g. structural e.g. photo mapping and e.g. special study of (outcrop and window geological mapping of rapid grid mapping of research nature based on mapping, ref. scale ca. surface outcrops, cleared outcrops, detailed outcrop or 2 10 m ) definition of systematic trench tunnel wall homogeneous domains, mapping surveying/sampling, representative grid mapping, etc., with orientations, etc. supporting laboratory studies Data source C C1-type data C2-type data C3-type data "Volumetric sampling" e.g. structural As B2, but 2-3 surfaces As B3, but 2-3 surfaces (tunnel mapping, ref. geological mapping , at right angles at right angles, + 3 scale ca. 35 m ) definition of (reconstruction in 3D) supporting core data, homogeneous domains, “TRUE-type” block representative reconstruction orientations, etc. with 3D view 11
2.2 Surface-based geological investigations
2.2.1 Surface data
Geological investigations of the outcrops and investigation trenches have been carried out on several occasions during the site investigations (Figure 2-1). The surveys have included mapping of lithologies, of structures of the ductile deformation (foliation, fold axis, axial planes, lineation), and, especially of fractures and brittle deformation zones. Outcrop mapping was carried out in 1988, 1991, 2003-2006, during which observations were made from more than 450 observation points within the whole island of Olkiluoto (see Appendix I). Since only about 4% of the bedrock at Olkiluoto is exposed, detailed mapping of excavated and cleaned investigation trenches has brought valuable bedrock and fracture data from areas with few or no outcrops. In 1995-1996 and 2002-2006, 13 investigation trenches were studied. The total length of the trenches is ca. 3 700 m and they range in width from 0.5 m to 5 m.
In the Olkiluoto area, a total of 16 021 tectonic measurements have been made, both on outcrops and in the investigation trenches, including 2 827 measurements of ductile deformation (foliation, fold axis, axial plane, fault plane and lineation) and 13 194 fracture measurements. During the mapping, the rock types were determined macroscopically from the exposed rock surfaces. At the same time, samples for further microscopic, geochemical and petrophysical analyses of rock types were taken. The petrography of a total of 58 rock samples was determined. Data categories and references are given in Table 2-2.
Table 2-2. Geological data from surface outcrops and investigation trenches at Olkiluoto: investigations, types of data, references and data categories - status of documentation, July 2007. Items in italics indicate studies which were not available at the time of writing of the version 0 report (Paulamäki et al. 2006).
Investigation Type of data Reference Category Petrographic and mineralogical Lithological mapping, microscopic Lindberg 1986 B1 study at the Ulkopää site investigations
Bedrock and fracture mapping Mapping of lithologies, structures Paulamäki B1 of the ductile deformation and 1989 fractures Interpretation of the geological Mapping of structures of the Paulamäki & B3 structures ductile deformation Koistinen 1991 Fracture mapping above the VLJ Fracture mapping Sacklén (1994) B1 repository Geological mapping of Mapping of lithologies, structures Paulamäki B2 investigation trench TK1 of the ductile deformation and 1995 fractures Geological mapping of two sludge Mapping of lithologies, structures Äikäs 1995 B2 basins of the ductile deformation and fractures Geological mapping of Mapping of lithologies, structures Paulamäki B2 investigation trench TK2 of the ductile deformation and 1996 fractures Geological mapping of Mapping of lithologies, structures Lindberg & B2 investigation trench TK3 of the ductile deformation and Paulamäki fractures 2004 12
Geological mapping of Mapping of lithologies, structures Talikka 2004 B2 construction site of OL3 of the ductile deformation and fractures Geological mapping of Mapping of lithologies, structures Paulamäki B2 investigation trench TK4 of the ductile deformation and 2005a fractures Geological mapping of Mapping of lithologies, structures Paulamäki & B2 investigation trench TK5 and TK6 of the ductile deformation and Aaltonen 2005 fractures Geological mapping of Mapping of lithologies, structures Paulamäki B2 investigation trench TK7 of the ductile deformation and 2005b fractures Geological mapping of ONKALO Mapping of lithologies, structures Talikka 2005 B2 open cut of the ductile deformation and fractures Geological mapping of Mapping of lithologies, structures Engström 2006 B2 investigation trench TK8 of the ductile deformation and fractures Geological mapping of Mapping of lithologies, structures Nordbäck & B2 investigation trench TK9 of the ductile deformation and Talikka 2006 fractures Dating of tonalitic gneiss, Petrographic and geochemical Mänttäri et al. B3 pegmatitic granite and diabase investigations 2006 dyke Geological mapping of Mapping of lithologies, structures Mattila et al. B2 investigation trench TK11 of the ductile deformation and 2007 fractures Geological mapping of Mapping of lithologies, structures Nordbäck & B2 investigation trench TK12 of the ductile deformation and Engström 2007 fractures Geological mapping of Mapping of lithologies, structures Talikka 2007 B2 investigation trench TK13 of the ductile deformation and fractures Geological mapping of the Mapping of structures of the Paulamäki B1 Olkiluoto region ductile and brittle deformation 2007 within the migmatite area and the Eurajoki rapakivi stock Structural mapping on islands Search for post-glacial faults Lindberg 2007 B1 surrounding Olkiluoto 13
Figure 2-1. Location of the outcrop observation points (red circles, GTK 1988-1991; blue triangles, Posiva Oy, 2003-2006)) and investigation trenches in the Olkiluoto site area (black lines). See also Appendix I.
2.2.2 Drillhole data
Deep core drilling from surface drilling sites has been carried out since 1988, with the total number of deep drillholes now exceeding 43 (Figure 2-2). Preliminary descriptions of all drill cores based on onsite core logging have been published as Posiva Working Reports. The drill cores are mostly 300 – 1000 m in length, with a combined length of 18 900 m. Gehör et al. (1996, 1997, 2000, 2005) and Lindberg & Paananen (1991, 1992) have presented the results of petrological studies from drillholes OL-KR1 – OL- KR28. These reports include the results of visual drill core loggings, polarisation microscope examinations and whole-rock chemical analyses of ca. 250 samples. Drillholes OL-KR29 – OL-KR38 were also logged during this work, but will be reported later.
The basic structural data for both the ductile and brittle deformation models was obtained during the spring and summer of 2005, covering drillholes OL-KR1 – OL- KR33B (Paulamäki et al. 2006). The work continued in autumn 2005 so that the structural data of drillholes OL-KR1 – OL-KR38B was available during this modelling work. Different elements and kinematic features of structural geological evolution were systematically logged along cored samples. The framework for the geological data acquisition along the drillholes is given in Milnes et al. (2007). 14
In addition to deep drillholes, 36 shallow (10-20 m) drillholes have been drilled to supplement the surface bedrock mapping (Suomen Malmi 1989). In the site area, there are also 16 shallow drillholes with the depth range of 14-36 m drilled earlier in the 1970s (Imatran Voima 1974) and re-logged in 1990 (Jokinen 1990).
Figure 2-2. Location of deep drillholes OL-KR1 – OL-KR43 in the Olkiluoto site area. 15
Table 2-3. Surface-based drillholes at Olkiluoto: investigations, types of data, references and data categories - status of documentation, July 2007. Items in italics indicate studies which were not available at the time of writing of the version 0 report (Paulamäki et al. 2006). Investigation Type of data Reference Category Standard geological Suomen Malmi Drilling of deep borehole OL-KR1 and engineering A1 (1989b) geological logging Standard geological Suomen Malmi Drilling of deep borehole OL-KR2 and engineering (1989c), Rautio A1 geological logging (1995c) Standard geological Suomen Malmi Drilling of deep borehole OL-KR3 and engineering A1 (1989d) geological logging Standard geological Rautio (1990, Drilling of deep borehole OL-KR4 and engineering A1 1995b) geological logging Standard geological Suomen Malmi Drilling of deep borehole OL-KR5 and engineering A1 (1990b) geological logging Standard geological Rautio & With Drilling of deep borehole OL-KR6 and engineering (1991), Rautio A1 geological logging (2000b) Standard geological Jokinen (1994), Drilling of deep borehole OL-KR7 and engineering A1 Rautio (2000a) geological logging Standard geological Rautio (1995a), Drilling of deep borehole OL-KR8 and engineering Niinimäki A1 geological logging (2002g) Standard geological Drilling of deep borehole OL-KR9 and engineering Rautio (1996b) A1 geological logging Standard geological Drilling of deep borehole OL-KR10 and engineering Rautio (1996a) A1 geological logging Standard geological Drilling of deep borehole OL-KR11 and engineering Rautio (1999) A1 geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR12 and engineering A1 (2000) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR13 and engineering A1 (2001a) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR14 and engineering A1 (2001b) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR15 and engineering A1 (2002a) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR16 and engineering A1 (2002b) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR17 and engineering A1 (2002c) geological logging 16
Standard geological Niinimäki Drilling of deep borehole OL-KR18 and engineering A1 (2002d) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR19 and engineering A1 (2002e) geological logging Standard geological Drilling of deep borehole OL-KR20 and engineering Rautio (2002) A1 geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR21 and engineering A1 (2002g) geological logging Niinimäki Standard geological (2002h), Drilling of deep borehole OL-KR22 and engineering A1 Niinimäki geological logging (2004b) Standard geological Niinimäki Drilling of deep borehole OL-KR23 and engineering A1 (2002i) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR24 and engineering A1 (2003a) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR25 and engineering A1 (2003b) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR26 and engineering A1 (2003c) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR27 and engineering A1 (2003d) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR28 and engineering A1 (2003e) geological logging Standard geological Drilling of deep borehole OL-KR29 and engineering Rautio (2004a) A1 geological logging Standard geological Drilling of deep borehole OL-KR30 and engineering Rautio (2004b) A1 geological logging Standard geological Drilling of deep borehole OL-KR31 and engineering Rautio (2004c) A1 geological logging Standard geological Drilling of deep borehole OL-KR32 and engineering Rautio (2005a) A1 geological logging Standard geological Drilling of deep borehole OL-KR33 and engineering Rautio (2005b) A1 geological logging Standard geological Drilling of deep borehole OL-KR34 and engineering Rautio (2005c) A1 geological logging Standard geological Drilling of deep borehole OL-KR35 and engineering Rautio (2005d) A1 geological logging 17
Standard geological Niinimäki & Drilling of deep borehole OL-KR36 and engineering A1 Rautio (2005) geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR37 and engineering A1 (2005a) geological logging Standard geological Drilling of deep borehole OL-KR38 and engineering Rautio (2005e) A1 geological logging Standard geological Niinimäki Drilling of deep borehole OL-KR39 and engineering A1 (2005b) geological logging Standard geological Pussinen & Drilling of deep borehole OL-KR40 and engineering Niinimäki A1 geological logging (2006a) Standard geological Pussinen & Drilling of deep borehole OL-KR41 and engineering Niinimäki A1 geological logging (2006b) Standard geological Pussinen & Drilling of deep borehole OL-KR42 and engineering Niinimäki A1 geological logging (2006c) Standard geological Drilling of deep borehole OL-KR43 and engineering Niinimäki (2006) A1 geological logging Petrographic, Lindberg & Petrography, lithogeochemistry and geochemical and Paananen A2 petrophysics, borehole KR1-KR5 geophysical investi- (1991a) gations Petrographic, Petrography, lithogeochemistry and geochemical and Lindberg & A2 petrophysics, borehole KR6 geophysical investi- Paananen (1992) gations Petrographic and Blomqvist et al. Dating of fracture minerals, borehole KR1 geochemical A3 (1992) investigations Petrographic and Petrology and low temperature fracture Gehör et al. geochemical A2 minerals, boreholes KR2-KR8 and KR10 (1996) investigations Petrographic and Petrology and low temperature fracture Gehör et al. geochemical A2 minerals, borehole KR9 (1997) investigations Petrographic and Isotopic and fluid inclusion study of fracture Blyth et al. geochemical A3 calcite, borehole KR1 (1998) investigations Petrographic and Petrology and low temperature fracture Gehör et al. geochemical A2 minerals, borehole KR11 (2000) investigations Petrographic and Petrology and low temperature fracture Gehör et al. geochemical A2 minerals, boreholes KR6-KR7 and KR12 (2001) investigations Imatran Voima Standard engineering Shallow drillings by IVO (1974), Jokinen A1 geological logging (1990) Standard engineering Suomen Malmi Shallow boreholes, PP1-PP36 A1 geological logging (1989e) 18
2.3 Surface-based geophysical investigations
Detailed descriptions of the applied geophysical data used for developing the geological model are given in Appendix II and are only briefly summarised in the following text.
2.3.1 Airborne and ground surveys
Geophysical airborne data has been acquired during two separate campaigns and the interpretation of the data is given in Paananen & Kurimo (1990), Paulamäki & Paananen (2001), Paulamäki et al. (2002) and Korhonen et al. (2005).
Geophysical ground surveys comprise magnetic and horizontal-loop EM measurements (Suomen Malmi Oy 1989, Lahti 2004). Furthermore, seismic refraction soundings (Lehtimäki 2003a,b; Ihalainen 2005) have been carried out in several separate campaigns. Impulse radar soundings and interpretations have been done as reconnaissance lines (Koskiahde 1988) and along investigation trenches TK3, TK4 and TK7 (Sutinen 2002 & 2003). Petrophysical data has been described in Paananen & Kurimo (1990) and Paananen (2004)
SAMPO Gefinex wide-band electromagnetic soundings have been carried out at Olkiluoto in four separate campaigns in 1990, 1994, 2002 and 2004 (Jokinen 1990; Jokinen & Jokinen 1994; Ahokas 2003; Jokinen & Lehtimäki 2004). The data has been used for mapping deep saline groundwaters, but it also gives information on sulphide minerals and possible deformation zones related to sulphide-rich locations.
In order to assess the potential of 3D seismics for imaging the upper 1 km of the crust and to gain some structural information, a 3D seismic pilot study was carried out at Olkiluto in 2006, on the western side of the ONKALO access tunnel (Juhlin & Cosma 2006). The survey covered an area of about 650 m x 600 m, using a fixed receiver array and a mechanical VIBSIST source. 19
Table 2-4. Geophysical data from airborne and ground surveys at Olkiluoto: investigations, types of data, references and data categories - status of documentation, July 2007. Items in italics indicate studies which were not available at the time of writing of the version 0 report (Paulamäki et al. 2006).
Investigation Type of data Reference Category Airborne survey: Magnetic, EM Airborne geophysics Suomen Malmi B2 and radiometric (1988) Magnetic and EM interpretation: Airborne geophysics Paananen & B2 magnetized units, rock types and Ground geophysics Kurimo (1990) electric conductors
Lineament interpretation Airborne geophysics Paulamäki & B2 Paananen (2001) Lineament interpretation Airborne geophysics Paulamäki et B2 al. (2002) Lineament interpretation Airborne geophysics Korhonen et al. B2 Ground geophysics (2005) Geophysical ground level survey Ground geophysics Suomen Malmi B2 Oy (1989) Magnetic and EM investigations Ground geophysics Lahti (2004) B2 Seismic refraction Ground geophysics Lehtimäki C2 (2003a,b) Refraction seismic investigation Ground geophysics Ihalainen C2 in OL-TK3 area (2005) Wide-band electromagnetic Ground geophysics Jokinen (1990) C2 soundings Wide-band electromagnetic Ground geophysics Jokinen & C2 soundings Jokinen (1994) Wide-band electromagnetic Ground geophysics Ahokas (2003) C2 soundings Wide-band electromagnetic Ground geophysics Jokinen & C2 soundings Lehtimäki (2004) Radar soundings Ground geophysics Koskiahde B2 Radar soundings Ground geophysics Sutinen (2002, B2 2003) Petrophysical data Ground geophysics Paananen & B2 Kurimo (1990) Petrophysical data Ground geophysics Paananen B2 (2004) 3D surface seismics Ground geophysics Juhlin & C2 Cosma (2007) 20
2.3.2 Drillhole logging and drillhole-based surveys
The single-hole geophysical data was available from deep boreholes OL-KR1…OL- KR40. (Niva 1989, Suomen Malmi Oy 1989, 1990, Julkunen et al. 1995, 1996, 2000a,b, 2002, 2003, 2004b,c, Julkunen & Kallio 2005a,b, Laurila & Tammenmaa 1996, Lowit et al. 1996, Lahti et al 2001, 2003, Heikkinen et al. 2004b, Lahti & Heikkinen 2005b, Majapuro 2005a,b, 2006a,b, Tarvainen 2006). Furthermore, data from pilot holes OL-PH1 (Julkunen et al. 2004a) and ONK-PH2…ONK-PH4 (Lahti & Heikkinen 2005a, Öhberg et al. 2006a,b) have been utilised. The single-hole data gathered comprises of different seismic (p-wave and s-wave velocity, p-wave and tubewave attenuation), radiometric (gamma-gamma, neutron- neutron), electric (long normal, short normal/wenner), magnetic, thermal and caliper data. The seismic, radiometric, and electric parameters have been mainly used in determining the locations of the deformation zones (however sulphides have a strong effect on electric measurements). The magnetic data is mainly used in locating ferrimagnetic, pyrrhotite-rich sections. Logging of gamma-ray spectrum in drillholes KR1, KR4 and KR27 was a new method applied in 2005 (Julkunen & Kallio 2005a,b). This survey provides K, equivalent U and equivalent Th content and total gamma radiation along the drillholes. Mise-à-la-masse surveys have been carried out at Olkiluoto as five separate campaigns in 1995 (Laurila 1995; Paananen 1996) 2003 (Lehtonen & Heikkinen 2004), 2004, 2005 and 2006 (Lehtonen 2006, Lehtonen & Mattila 2007). They have been used in mapping brittle deformation zones (especially in mapping water conductive zones), but they also give information on sulphide minerals and possible deformation zones related to sulphide-rich locations. Vertical seismic profiling (VSP) surveys have been carried out as several campaigns in 14 drillholes (KR1-KR10, KR12-KR14, KR19) at Olkiluoto, starting in 1990. Over the years, the survey technique as well as the interpretation procedure has been greatly developed. In this study, the VSP interpretation results from each borehole in the Site model area have been examined and correlated to geological data. The most recent VSP results are from the following boreholes, located in the ONKALO area:
x KR7, KR8 (Cosma et al. 2003, Heikkinen et al. 2004)
x KR4, KR10, KR14 (Enescu et al. 2004, Heikkinen et al. 2004).
Furthermore, HSP results from the Korvensuo reservoir (Cosma et al. 2003) and crosshole surveys between KR14 and KR15 (Enescu et al. 2003) and KR4 and KR10 (Enescu et al. 2004) have been available. In addition to this, the results of the Walkaway Vertical Seismic Profiling (WVSP) from boreholes KR4, KR8, KR10 and KR14 (Enescu et al. 2004, Heikkinen et al. 2004) were available. Since many different geological features may induce seismic reflectors, they must be checked against geological and single-hole geophysical data. A comprehensive validation of VSP results from drillholes KR4, KR7, KR8, KR10 and KR14 has been done by Heikkinen et al. (2004). According to their conclusions, c. 60 – 70% of the gently dipping reflectors can be explained by elevated fracturing. From all the reflectors, c. 30 – 40 % appears to coincide with lithological contacts. Overall, 60 – 70% of the reflectors could be explained with the existing geological data. 21
Drillhole radar surveys have been done at Olkiluoto in 9 drillholes (KR1 – KR8, KR10) as several separate campaigns (Carlsten 1990, 1991, 1996a, 1996b). After 1996, no new radar measurements in drillholes have been carried out. The applicability of this method is highly limited at Olkiluoto due to the presence of saline groundwater and mineral conductors. Furthermore, geological structures intersecting the drillholes at a high angle (>75 degrees) are difficult to detect by drillhole radar.
Table 2-5. Geophysical data from drillhole logging and drillhole-based experiments at Olkiluoto: investigations, types of data, references and data categories - status of documentation, July 2007. Items in italics indicate studies which were not available at the time of writing of the version 0 report (Paulamäki et al. 2006)
Investigation Type of data Reference Category Geophysical borehole logging of Single-hole geophysics Niva (1989) A1 OL-KR1 Geophysical borehole logging of Single-hole geophysics Suomen Malmi A1 OL-KR4 and KR5 Oy (1989, 1990) Geophysical borehole logging of Single-hole geophysics Julkunen et al. A1 OL-KR2-KR4, KR6, KR7, KR9, (1995; 1996; KR11, KR12, KR15-KR18, 2000a,b; 2002; KR23-KR28, OL-PH1, 2003; 2004a,b, c) Borehole gama-ray spectrum Single-hole geophysics Julkunen & A2 logging of OL-KR4 Kallio (2005a,b) Borehole gama-ray spectrum Single-hole geophysics Laurila & A2 logging of OL-KR1 and OL- Tammenmaa KR27 (1996) Geophysical borehole logging at Single-hole geophysics Lowit et al. A2 Olkiluoto, dual neutron and full (1996) waveform sonic log Geophysical borehole logging of Single-hole geophysics Lahti et al. A1 boreholes OL-KR13 and KR14, (2001, 2003) KR19-KR20, KR8 Geophysical borehole logging of Single-hole geophysics Heikkinen et A1 boreholes OL-KR13 and KR14 al. (2004b) Geophysical borehole logging of Single-hole geophysics Lahti & A1 boreholes OL-KR23 and KR29 Heikkinen (2005b) Geophysical borehole logging of Single-hole geophysics Majapuro A1 OL-KR30 – KR38 and OL-KR24 (2005a,b; 2006a,b) Geophysical borehole logging of Single-hole geophysics Tarvainen A1 boreholes OL-KR31, KR39 and (2006) KR40b Mise-à-la-masse survey, year Mise-à-la-masse Laurila (1995) A2 1995 Interpretation of year 1995 mise- Mise-à-la-masse Paananen A2 à-la-masse survey data (1996) Visualisation and interpretation of Mise-à-la-masse Lehtonen & A2 year 2003 mise-à-la-masse survey Heikkinen data (2004) 22
Visualisation and interpretation of Mise-à-la-masse Lehtonen A2 year 2004 mise-à-la-masse survey (2006a) data Visualisation and interpretation Mise-à-la-masse Lehtonen A2 of year 2005 mise-à-la-masse (2006b) survey data Visualisation and interpretation Mise-à-la-masse Lehtonen & A2 of year 2006 mise-à-la-masse Mattila (2007) survey data Cross-hole correlation of the Mise-à-la-masse Paananen et al. A2 MAM results (2007) VSP and HSP in Olkiluoto 2002 Seismic drillhole measurements Cosma et al. A2 (2003) Reflection seismics using Seismic drillhole measurements Heikkinen et A2 boreholes at Olkiluoto in 2003 al. (2004) Reflection seismics using Seismic drillhole measurements Enescu et al. A2 boreholes at Olkiluoto in 2003 (2004) VSP and crosshole investigations Seismic drillhole measurements Enescu et al. A2 in Olkiluoto 2002 (2003) Drillhole radar survey OL- Drillhole radar profiling Carlsten (1990, A2 KR1…OL-KR8 and OL-KR10 1991, 1996a, 1996b) Petrophysical data, drillholes OL- Drillhole petrophysics Lindberg & A2 KR1…OL-KR6 Paananen (1991a, 1991b, 1992)
2.4 Underground investigations
2.4.1 Tunnel mapping
The excavation of the ONKALO underground rock characterisation facility was started in September 2004 and in May 2007 the access tunnel has reached the length of 2000 metres (corresponding to the depth of approximately 190 metres below sea level). Geological mapping of the ONKALO tunnel has been performed systematically in increments of 5 metres, corresponding to the length of one excavation round. The mapping includes the determination of rock types, measurement of structural features (foliation, fold axis, axial planes, slip lineation and slip sense of brittle deformation features) and detailed mapping of fractures of all trace lengths. Sections of increased fracturing in the ONKALO tunnel were mapped and subdivided in the same way as in the logging of brittle deformation products from the drill cores.
The results of the geological mapping of the ONKALO tunnel are reported as geological outcomes, each covering a section of the tunnel either with or without pilot holes; the mapped sections range from 150 to 400 metres in length. The outcomes of the tunnel survey have been used in the construction of the present geological model, although currently the outcomes have only been reported as memos; in the near future the results will be published in Posiva Oy’s working report series. The currently reported outcomes correspond to tunnel sections 0-140 (corresponding to the location of pilot hole OL-PH1), 140-310 (ONK-PH2), 310-700, 700-850 (ONK-PH3) and 850-990 (ONK-PH4). As an example, measured foliation orientations from specific tunnel sections are shown in Figure 2-3, which shows generally SE to SEE dipping foliation 23
with moderate dip and with slight variation in the orientation and dip. Similarly, measured fracture orientations from specific tunnel sections are shown in Figure 2-4, which shows high variation in the orientations, although certain orientation clusters can be recognised by contouring the data – main fracture orientation clusters are vertical to subvertical, striking approximately towards S-SE and N-NW, horizontal, and SE- dipping, with moderate dip.
Up to the chainage of 990 metres, the tunnel has intersected a total of 23 deformation zone intersections of which 19 are categorised as brittle deformation zone intersections and 4 as high-grade ductile deformation zones (for an explanation of the classification system, see Milnes et al. 2007 and the following chapters). For each deformation intersection, a geological description is given and the geometries are mapped in detail, which thus provides the framework in the modelling of zones in 3D. As an example of the data produced, a 2D map of the encountered deformation zones is shown Figure 2-5. Similarly, an example of the lithological data, a 2D map is shown in Figure 2-6. 24
A. B.
C. D.
E.
Figure 2-3. Measured foliation orientations at specific sections of the ONKALO tunnel. (A) Tunnel section 0-140, 90 poles; (B) 140-310, 34 poles; (C) 310-700, 35 poles; (D) 700-850, 22 poles and (E) 850-990, 12 poles. Equal Area, lower hemisphere stereograms. 25
A. B.
C. D.
E.
Figure 2-4. Measured fracture orientations at specific sections of the ONKALO tunnel. (A) Tunnel section 0-140, 2088 poles; (B) 140-310, 1526 poles; (C) 310-700, 2382 poles; (D) 700-850, 810 poles and (E) 850-990, 1136 poles. Equal Area, lower hemisphere stereograms. 26
Figure 2-5. Mapped deformation zone intersections and tunnel crosscutting fractures (full perimeter intersections, FPI’s in the SKB nomenclature) from the ONKALO access tunnel, at chainage 820-1000. BFI=brittle fault zone intersection, HGI=high-grade ductile deformation zone intersection, and TCF=tunnel crosscutting fracture. PL### refers to chainage and P## to a tunnel crosscutting fractures. 27
Figure 2-6. Mapped lithology of the ONKALO access tunnel, at chainage 820-1000 m. MGN=mica gneiss, QGN=quartz gneiss, MFGN=mafic gneiss, TGG=tonalitic, granodioritic, granitic gneiss, PGR=pegmatitic granite, SGN=stromatic gneiss, DGN=diatexitic gneiss, and VGN=veined gneiss. PL### refers to chainage.
2.4.2 Pilot drillholes
Pilot holes ONK-PH1 - ONK-PH6 (Table 2-6) have been drilled down the centre line of the ONKALO access tunnel, as part of the ONKALO investigations. In addition, 7 shallow (15.2-45.80 m) drillholes OL-PP40 - OL-PP41 and OL-PR5 – OL-PR9 have been drilled directly above the access tunnel. 28
Table 2-6. Pilot drillholes in the ONKALO access tunnel: investigations, types of data, references and data categories - status of documentation, July 2007. Items in italics indicate studies which were not available at the time of writing of the version 0 report (Paulamäki et al. 2006).
Investigation Type of data Reference Category Standard geological Niinimäki Drilling of pilot hole OL-PH1 and engineering A1 (2004) geological logging Standard geological Öhberg et al. Drilling of pilot hole ONK-PH2 and engineering A1 2005 geological logging Standard geological Öhberg et al. Drilling of pilot hole ONK-PH3 and engineering A1 2006a geological logging Standard geological Öhberg et al. Drilling of pilot hole ONK-PH4 and engineering A1 2006b geological logging Standard geological Öhberg et al. Drilling of pilot hole ONK-PH5 and engineering A1 2006c geological logging
2.4.3 Analogue studies – VLJ access tunnel and repository
The VLJ repository, situated at the depth of 70—100 metres in the crystalline bedrock, was constructed at Olkiluoto, about 1.5 km west of the site area, in 1988-1989, to be used for the disposal of low-level maintenance waste and intermediate-level operating waste. The geological studies performed before the excavation of the repository are summarised in Äikäs (1986). The results of the engineering geological mapping of the tunnels, shafts and waste silos are presented in Ikävalko & Niskanen (1989a,b) and Ikävalko & Äikäs (1991). A short research tunnel within the repository was mapped in detail by Äikäs & Sacklén (1993). Front & Pitkänen (1991) have studied the porous pegmatite from the fracture zone in the VLJ-repository and Front and Kontio (1994) have analysed fracture data from the repository. Lindberg & Paananen (1991b) have made petrographic and petrophysical studies on selected samples from the repository. A list of published references is shown in Table 2-7. 29
Table 2-7. Geological data from the VLJ repository - analogue underground data from a location near the Olkiluoto site: investigations, types of data, references and data categories - status of documentation, July 2007. Items in italics indicate studies which were not available at the time of writing of the version 0 report (Paulamäki et al. 2006).
Investigation Type of data Reference Category Ikävalko & Engineering geological mapping of the access Engineering geological Niskanen C1 tunnel of the VLJ repository mapping (1989a,b) Engineering geological Ikävalko & Geological mapping of the VLJ repository C1 mapping Äikäs (1991) Petrographic and Lindberg & A2 Petrography and Petrophysics, VLJ repository geophysical investi- Paananen gations (1991b) Fracture mapping of the research tunnel in the Engineering geological Äikäs & Sacklén C1 VLJ repository mapping (1993) Front and Kontio Analysis of fracture data from the VLJ tunnel Geological mapping C1 (1994) Petrographic and A2 Study of porous pegmatite in the VLJ geochemical Front & repository investigations Pitkänen (1991)
2.5 Other sources of data
References given in the following table cannot be addressed by the classification presented in Table 2-1, but provide important background material e.g. for the development of the site understanding.
Table 2-8. Other sources of data: investigations, types of data and references - status of documentation, July 2007. Items in italics indicate studies which were not available at the time of writing of the version 0 report (Paulamäki et al. 2006).
Investigation Type of data Reference Literature survey on the structure and Literature compilation and Paulamäki et al. 2002 geological evolution of the bedrock in interpretation of the aeromagnetic southern Satakunta lineaments Lineament interpretation Interpretation of the topographic data Kuivamäki (2000) Lineament interpretation Interpretation of the topographic data Kuivamäki (2001) Lineament interpretation Interpretation of the topographic and Kuivamäki (2005) acoustic-seismic data Literature survey on the characterisation Literature compilation Milnes (2006) of brittle deformation at Olkiluoto Literature survey on the geological Literature compilation Paulamäki & evolution of the Fennosacndian shield Kuivamäki (2006) during the last 1300 years. U-Pb ages for rock types at Olkiluoto Age determination Mänttäri et al. (2006) U-Pb ages for rock types from OL-TK13 Age determination Mänttäri et al (2005) K-Ar age determination for fault breccia Age determination Mänttäri et al (2007) samples Characterisation of foliation at Olkiluoto Methodology for the characterisation Milnes et al. (2006), of foliation at Olkiluoto and results Palmen (2004), of pilot studies Aaltonen (2005) Regional lineament analysis Interpretation of the topographic and Paananen & airborne magnetic data Kuivamäki (2007) 30
2.6 Feedback from other disciplines, the integrated ONKALO area model and prediction-outcome studies
Geological Site Modelling is a part of the Olkiluoto Site Descriptive Modelling, the results of which have been documented in respective Site Descriptive Model reports (Posiva Oy 2005, Andersson et al. 2007). The main focus of the Site Descriptive Model Reports is to provide an integrated, comprehensive view of the properties of the bedrock and the biosphere, applicable to further safety analysis and layout designs. As a part of the Site Descriptive modelling and the integration of discipline-specific models, the development of the Geological Site Model has greatly benefited from the discussions with the end users of the model, i.e. rock mechanics, hydrogeology and hydrogeochemistry groups, during the many integration meetings after the release of the Geological Site Model version 0 (Paulamäki et al. 2006). As an example, for hydrogeological modelling, the key function of the geological model is to provide the geometrical background of deformation zones, which describes the potential pathways for fluid flow. Therefore, in the current model, much emphasis is placed on the definition of the extent of the zones and for this approach extensive use of geophysical data has taken place. As an example, in Figure 2-7, the correspondence of hydrogeological zone BFZ20B and HZ20B_Alt (Ahokas et al. 2007) and geological zone BFZ080 is shown in 3D (Figure 2-7A) and as a horizontal profile in 2D (Figure 2-7B). The main geometry of the zones is very similar, giving confidence to the models, although in the locations of drillhole intersections there may be some variation, as high- T values in drillholes (which has been the basis on the definition of hydrogeological zones) may not always correspond to the exact location of geologically defined fault cores (for definition of fault core, see Chapter 4.5). Similarly, the extents of the zones may differ due to differences in the observed hydrological and geophysical connections, leading to different sizes for the zones. 31
A.
B.
Figure 2-7. Comparison of hydrogeological zones HZ20B and HZ20B_Alt (in blue) and geological brittle deformation zone BFZ080 (in light brown) in (A) 3D and (B) horizontal 2D sections at the level –420 m. 32
The recently published integrated model of the ONKALO area (Kemppainen et al. 2007) revised many of the hydrologically and geophysically defined site-scale zones, which have been known already since the beginning of the Site investigations and reported in detail, for example in Vaittinen et al. (2003), by new hydrological and geophysical data. For the present geological model, these zones were reanalysed from the perspective of geological data and incorporated as site-scale fault zones, where applicable, although the exact locations and sizes of the zones are somewhat different from the previous models due to the newly adopted system of defining fault cores and influence zones (see Chapter 4.5 for a detailed account of the terms). An example of, the correspondence of the zone ONK20B from the ONKALO area model to brittle deformation zone BFZ080 is shown in Figure 2-8. 33
A.
B.
Figure 2-8. Comparison of integrated zone ONK20B (in green) and geological brittle deformation zone BFZ080 (in light brown) in (A) 3D and (B) horizontal 2D sections at the level –420 m. 34
One important activity of the Olkiluoto site models is to make predictions of the properties of the bedrock that will be encountered during the construction of ONKALO; furthermore, these predictions should be compared with the outcome following the mapping of the tunnel. The results of these so-called prediction-outcome (Andersson et al. 2005) studies will be then utilised for the revision and development the site descriptive models and applied modelling methodologies. Currently, the results of only one comparison of geological predictions and outcomes have been published (Andersson et al. 2007), but further work is ongoing to estimate the effects of other predictions and outcomes. As an example of the use of the results from prediction- outcome studies, in Figure 2-9A the geological zones predicted for the tunnel section 850-1000 have are shown, as in Figure 2-9B the zones observed during tunnel mapping are shown as projections in 2D map. From these two figures it is evident that a certain similarity between the prediction and outcome exists, especially when concerning the location of the zones, whereas in the details of the zones (thickness, dip, dip direction) there is clearly higher deviation. This may be attributed to the use of the orientations of slickensides in the modelling of fault zones in the last model version (Paulamäki et al. 2006) and the uncertainties inherent in the method. Based on these realisations, in the current model much less emphasis was put on the use of slickensides orientations, whereas geophysical data was exploited more extensively as this seems to provide more accurate information on the orientations in larger scale. Therefore, based on the practical observations in relation to the existing models, modelling methodologies have been changed to improve the predictive capability of the model. As new zones are encountered, similar estimations will be continued. The geological zones of the current model, which are located in the tunnel section 850-1000, are shown in Figure 2-9C. 35
A.
B. 36
C
Figure 2-9. Geological zones (light brown) from the Geological Site Model v. 0 (Paulamäki et al. 2006) predicted for the tunnel section 850-1000 (A), observed deformation zones and tunnel crosscutting fractures for tunnel section 850-1000 (B) and geological zones (light brown colour) from Geological Site Model v. 1.0 (this report) modified according to the results observed from the tunnel mapping. ONKALO layout is shown in red in (A) and (C). 37
3 GEOLOGICAL EVOLUTION OF THE BEDROCK
3.1 Overview to the geology of Finland
The crystalline bedrock of Finland (Figure 3-1) is a part of the Precambrian Fennoscandian Shield. The oldest part of the Finnish bedrock formed by the Archaean Karelian craton (3500 – 2500 Ma) in northeastern Finland consists mainly of different granitoids and high-grade tonalitic and granodioritic gneisses (Gaál & Gorbatschev 1987, Vaasjoki et al. 2005). Within the basement complex are narrow Archaean greenstone belts, ca. 2800 Ma in age, which contain abundant tholeiitic and komatiitic metavolcanics, as well as metasediments. About 2440 Ma ago layered gabbro intrusions (no. 31 in Figure 3-1 ) were emplaced in northern and northeastern Finland (Alapieti 1982) together with accompanying mafic dyke swarms (Vuollo 1994). The Archaean craton is discordantly overlain by 2500 - 2000 Ma old metasediments and metavolcanics (nos. 20, 27 - 29, 30 and 32 in Figure 3-1), which are cut by 1970 - 2200 Ma diabase dykes (Laajoki 1991). About 1960 Ma old ophiolite complexes in eastern Finland (no. 22 in Figure 3-1) represent an ancient ocean floor.
The central and southern parts of the Finnish bedrock comprise Early Palaeoproterozoic metamorphic and igneous rocks, belonging to the Svecofennian Domain (nos. 13-19 and 21 in Figure 3-1) (Gaál & Gorbatschev 1987, Koistinen 1996, Vaasjoki et al. 2005). This domain was developed between 1930 Ma and 1800 Ma either during one long Svecofennian orogeny (see, e.g., Lahtinen 1994, Nironen 1997, Korsman 1999), or during several separate orogenies (Lahtinen 2005, Korja & Heikkinen 2005). Later the crust was intruded by Mesoproterozoic anorogenic rapakivi granites, 1650 – 1540 Ma in age, with associated minor gabbro and anorthosite intrusions, and mafic dyke swarms. The youngest basement rocks are the so-called Jotnian sandstones, ca. 1400 – 1300 Ma, 1270 – 1250 Ma old olivine diabase dykes, and the 1100 and 1000 Ma old dykes of Salla and Laanila in northern Finland.
The bedrock had been eroded almost to its present level before the beginning of the Cambrian (about 600 million years ago). Due to erosion and continental conditions there is an almost total absence of sedimentary rocks younger than the Precambrian. In eastern Finland, kimberlites were emplaced at ca. 600 Ma, and in northeastern Finland there is one alkaline and one carbonatite intrusion with the age of 370-360 Ma (no. 2 in Figure 3-1). 38
Figure 3-1. Bedrock of Finland. ©Geological Survey of Finland, Espoo 1999. 39
3.2 Regional geology
In this chapter, a brief summary of the evolution of the bedrock in the southern Satakunta area, to which Olkiluoto belongs, is given. For a more comprehensive description of the geology of the area, the reader is referred to Paulamäki et al. (2002) and Paulamäki & Kuivamäki (2006) and references therein.
3.2.1 Palaeoproterozoic lithology
The Palaeoproterozoic bedrock of southern Satakunta can be subdivided into three main domains: a pelitic migmatite belt in the southwest, a central area of rapakivi granites, sandstone and olivine diabases, and a psammitic migmatite belt in the northeast (PEMB and PSMP, respectively in Figure 3-2 and Figure 3-3). The pelitic and psammitic migmatite belts can be distinguished on the basis of the predominant granitic and trondhjemitic to granodioritic leucosomes, respectively (Korsman et al. 1999). Amphibolites, uralite porphyrites and hornblende gneisses, which were originally mafic and intermediate volcanics, occasionally occur as narrow interlayers in the supracrustal sequences. Plutonic rocks consisting of trondhjemites, tonalites, granodiorites, coarse- grained granites and pegmatites intrude the migmatites. Except for a few small bodies of gabbros and diorites, more mafic intrusive rocks are encountered only as small xenoliths.
3.2.2 Deformation and metamorphism
The Palaeoproterozoic supracrustal rocks of the area have undergone a polyphasic deformational history. The earliest observed tectonic structure is the biotite foliation S1 parallel to the bedding. The dominant foliation is usually penetrative S2 with tectonic/metamorphic segregation. The D2 deformation is characterised by recumbent or reclined F2 folds with NE-SW-trending subhorizontal to gently plunging fold axes and axial planes (Selonen & Ehlers 1998, Väisänen & Hölttä 1999). The recumbent attitude of F2 folds suggests a layer-parallel shearing and over- or underthrusting during D2, although no major thrust zones have been identified (Väisänen & Hölttä 1999). Compared to the pelitic migmatite belt, F2 folds of the same age in the psammitic migmatite belt have vertical axial planes (Kilpeläinen 1998). The synorogenic tonalite- granodiorite intrusions were emplaced before or during the deformation phase D2. Both D1 and D2 structures are deformed by the regional F3 folding of the deformation phase D3 (Väisänen & Hölttä 1999). The fold axis is generally horizontal or moderately plunging, and fold limbs are often strongly sheared. Late-orogenic potassium granites were emplaced during D3 in the pelitic migmatite belt. In the pelitic migmatite belt, D4 structures are local N-S to NNE-SSW -striking shear zones, cross-cutting the previous structures. Both ductile and brittle structures occur, usually both in the same shear zone. In the Pori area in the psammitic migmatite belt, D4 structures are local, open dextral folds and shears (Pajunen et al. 2001).
The age of the D2 deformation is close to the age of the synorogenic granitoids, 1890 - 1880 Ma (Selonen & Ehlers 1998, Nironen 1999, Väisänen & Hölttä 1999). In the psammitic migmatite belt, the age of the deformation interpreted as D3 therein is considered to be about 1885 to 1870 Ma (Nironen 1999). In the pelitic migmatite belt, however, the age of the deformation, defined as D3 therein, is close to the age of the late-orogenic microcline granites (1840 - 1830 Ma) (Väisänen & Hölttä 1999, Väisänen 40
et al. 2002). According to Väisänen et al. (1994) and Väisänen & Hölttä (1999) the D4 shear zones may be associated with the postorogenic granite-intrusions of southwestern Finland dated at 1815 - 1770 Ma (see Suominen 1991, Vaasjoki 1996).
The Palaeoproterozoic Svecofennian Domain is characterised by a high-temperature, low-pressure metamorphism (Korsman et al. 1999). Typical metamorphic minerals, porphyroblasts, in pelitic metasediments are andalusite, staurolite, garnet, cordierite, sillimanite and potassium feldspar. The temperature of the metamorphism is estimated to have occurred at 650 - 700°C and 4 - 5 kb pressure, corresponding the upper amphibolite facies. The peak temperature of 700 - 800°C was attained in the migmatite areas under pressures of 4 - 6 kb.
The Svecofennian high-temperature, low-pressure metamorphism is attributed to thinning of the tectonically thickened crust and subsequent intra- and underplating, which led to a strong increase in temperature (Korja et al. 1993, Lahtinen 1994, Nironen 1997, Korsman et al. 1999).
In the psammitic migmatite belt the peak temperature of 800 - 670°C and pressure of 5 - 6 kbar were attained at about 1885 Ma during a thermal pulse caused by the intrusion of the granitoids, dated at 1889 - 1880 Ma, and the metamorphic evolution ceased soon after. The metamorphism took place during or after the D2 deformation but before the D3 deformation (Korsman et al. 1999, Väisänen & Hölttä 1999). Also the pelitic migmatite belt was metamorphosed at the same time but there the older metamorphism is overprinted by younger metamorphism, caused by a new, strong thermal pulse. This metamorphic event took place 1860 - 1810 Ma ago at the peak temperatures of 700 - 800°C and the pressures of 4 - 5 kbar, producing abundant potassium granite melts (microcline granites dated at 1840 - 1830 Ma). The peak metamorphic temperatures and pressures correspond to the depth of 13 - 16 km (Korsman 1977, Hölttä 1988). In the psammitic migmatite belt, for example, in the Vammala area, the younger metamorphism is only locally visible (Kilpeläinen et al. 1994). PSMB 41
PEMB
Figure 3-2. Regional geology of Olkiluoto (from Anttila et al. 1999). The location of Olkiluoto is marked with a box. PEMB = pelitic migmatite belt, PSMB = psammitic migmatite belt (see text). 42
3.2.3 Palaeoproterozoic tectonic evolution
The model of the tectonic evolution of the Paleoproterozoic bedrock in southern Finland given here is mainly based on interpretations by Lahtinen (1994), Nironen (1997), Korsman et al. (1999), and it has been more thoroughly summarised in Paulamäki et al. (2002). These models are all based on the concept of one single long Svecofennian orogeny. Recently, however, Lahtinen et al. (2005) have divided the former Svecofennian orogeny into five separate orogenies, which overlap in time and space, and which include an amalgamation of several microcontinents and island arcs.
According to research by Lahtinen (1994), Nironen (1997) and Korsman et al. (1999), the supracrustal rocks of the study area represent sedimentation in two separate island arc environments, the rocks of the psammitic migmatite belt and the pelitic migmatite belt belonging to the Central Finland and Southern Finland continental arcs (Southern Finland sedimentary-volcanic complex), respectively (Figure 3-3). The rifting of the protocrust began before 1910 Ma and subduction zones, where oceanic crust was destroyed, developed both on the northern and southern margins of the opening ocean. The subduction both to the north and south resulted in the formation of the Central Finland and Southern Finland arcs, respectively.
Accretion of the Southern Finland continental arc to the Central Finland continental arc took place 1890 - 1880 million years ago (the Fennian orogeny of Lahtinen et al. 2005). A possible suture zone is located in the southern part of the psammitic migmatite belt. The collision of the arc complexes is characterised by intense magmatic activity, which appears as synorogenic granitoids, mainly dated at 1890 - 1880 Ma. In the study area they are mainly granodiorites, tonalites and trondhjemites. The synorogenic intrusions were emplaced before or during deformation phase D2. During the accretion and the subsequent magmatic activity the sedimentary and volcanic rocks were metamorphosed for the first time. The high temperature-low pressure metamorphism was caused by magmatic underplating, which led to a radical increase in temperature and recrystallisation and partial remelting of the rocks in the upper crust. Both in the pelitic migmatite belt and the psammitic migmatite belt, the peak of the metamorphism was achieved during and after deformation phase D2 but before deformation phase D3.
According to Lahtinen et al. (2005), the Fennian orogeny ended in orogenic collapse associated with regional extension and crustal thinning at 1860-1840 Ma. In southern Finland, the Fennian orogeny was followed by a new period of crustal shortening and thickening at 1840-1800 Ma. This stage, defined as the Svecobaltic orogeny by Lahtinen et al. (2005), is characterised by a strong thermal pulse, which caused a high temperature (700 - 800°C) metamorphism and almost total melting of the sedimentary rocks. It is manifested as a ca. 100 km wide and 500 km long belt of potassium granites, dated at 1850 - 1820 Ma. They are classified as so-called S-type granites, which have been formed by partial melting of the sedimentary rocks deep in the crust. The metamorphism and the partial melting were caused by mafic underplating after lithospheric delamination. Ehlers et al. (1993) and Stålfors & Ehlers (2005) suggest that the granites were emplaced within the crustal-scale transpressional shear zones.
A post-collisional period of intense uplift at ca. 1800 Ma has been suggested by Väisänen (2002) on the basis of studies in the Turku area, southwestern Finland. 43
Figure 3-3. Main geotectonic units of the Svecofennides (Korsman et al. 1999). The location of the southern Satakunta area is marked with a red square. The polygon outlines the geophysical GGT/SVEKA transect. TTG = tonalite-trondhjemite- granodiorite.
3.2.4 Later events not related to orogeny/orogenies
The northern part of the Mesoproterozoic anorogenic Laitila rapakivi batholith, dated at 1583±3 Ma (Vaasjoki 1996a), is located in the central part of the region and comprises several different types, which differ from each other in texture and mineral composition (Vorma 1976, Veräjämäki 1998). The Eurajoki rapakivi stock, located 5 km east of Olkiluoto, is a satellite massif of the Laitila batholith, and can be divided into two types, hornblende-bearing Tarkki granite (age 1571±3 Ma; Vaasjoki 1996a) and younger, light-coloured topaz-bearing Väkkärä granite (age 1548±3 Ma; Vaasjoki 1996a) (Haapala 1977). The rapakivi magmas were formed by extensive melting of the lower crust in an extensional tectonic regime and intruded into higher crustal levels along shear zones and faults, which already existed before the rapakivi batholiths (Rämö & Haapala 2005). 44
After the rapakivi magmatism and before the exposure of the rapakivi granites, the Satakunta sandstone was deposited in a graben formed during the rifting period ca. 1650 Ma ago. The Satakunta sandstone has been interpreted as being a fluvial sediment formation deposited in an alluvial environment (Kohonen et al. 1993). The upper parts of the sandstone were deposited ca. 1400 - 1300 Ma ago. Sandstones are present also in the Bothnian Sea below the Palaeozoic rocks as a submarine continuation of the sandstone formations in Satakunta, and in the Gävle area on the east coast of Sweden. In Satakunta, block movements occurred after the formation of the sedimentary basin and the deposition of the sandstone, as evidenced by the presence of tilted sandstone beds in the northeastern part of the graben. Based on one drillhole and geophysical interpretation, the thickness of the sandstone is at least 600 m, and probably as much as 1800 m. The sandstone was originally distributed over a much larger area but, at present, only the part protected by the subsided graben is preserved
The sandstone is cut by Mesoproterozoic olivine diabase dykes and sills, 1270 – 1250 million years in age (Suominen 1991). Their geochemical features suggest that they are feeder channels to continental flood basalts, which, however, have not been preserved in the Satakunta area. The olivine diabases in Finland and Sweden (the Central Scandinavian Dolerite Group), and related diabases in Greenland are considered to represent the initial rifting between the Baltica and Laurentia cratons at the onset of the Sveconorwegian orogeny (see Paulamäki & Kuivamäki 2006 and references therein). The Kokemäki low-altitude aeromagnetic map suggests that the olivine diabase dykes and sills are cut by younger diabase dykes trending almost north-south but these dykes are not exposed.
In the Bothnian Sea basin, the sandstone is overlain by Cambrian and Lower Ordovician sandstones, siltstones and mudstones, which are covered by Middle and Upper Ordovician carbonate rocks (see Paulamäki & Kuivamäki 2006 and references therein). The bedrock movements after the deposition of the Palaeozoic sediments are demonstrated by faults cutting the Proterozoic basement and the overlying Palaeozoic sedimentary cover.
Although Palaeozoic sedimentary rocks do not today exist onshore in southern Satakunta, large parts of the Precambrian bedrock were once covered by them, as indicated by the presumably Lower Cambrian sandstone dykes in Åland, in the Turku archipelago and in the Vehmaa and the Laitila rapakivi granite batholiths. Apatite fission track studies indicate that extensive Silurian to Devonian deposits most likely covered large parts of the Fennoscandian Shield, with an estimated thickness of 3 - 4 km in Sweden and ca. 1 km in the Satakunta area (see Paulamäki & Kuivamäki 2006 and references therein). These deposits were derived from the eroded Caledonian mountain chain along the north-western margin of the Fennoscandian shield. The Palaeozoic-Mesozoic sedimentary cover still existed ca. 75 Ma ago, as evidenced by the sedimentary rocks in the Lappajärvi meteorite impact crater, but eroded away probably by late Mesozoic-early Cenozoic (Kohonen & Rämö 2005). In the Paleogene and Neogene, tectonic uplift measuring 1-2 km took place in western Scandinavia in connection with the opening of the North Atlantic. It has been estimated that the uplift in the Bothnian Sea area was about 500 m. 45
3.3 Local geology
3.3.1 Lithological relations
In this chapter the main emphasis is on the geological evolution of the various lithologies of Olkiluoto. The comprehensive petrographic and geochemical description of the lithologies is presented in Kärki & Paulamäki (2006) and extensively summarized in Paulamäki et al. (2006). Lithological map of Olkiluoto is shown in Appendix IV.
The bedrock of Olkiluoto mostly comprises high-grade metamorphic supracrustal rocks, the source materials of which are epiclastic and pyroclastic sediments. These rocks are migmatised by abundant leucocratic pegmatitic granites and cut by a few narrow mafic dykes. In terms of their mineral composition, texture and migmatite structure, the rocks of Olkiluoto can be divided into four major classes: 1) migmatitic gneisses, 2) tonalitic- granodioritic-granitic gneisses (or TGG gneisses), 3) other gneisses including mica gneisses, quartz gneisses and mafic gneisses, and 4) pegmatitic granites. The migmatitic rocks can further be subdivided into stromatic gneisses, veined gneisses and diatexitic gneisses on the basis of their migmatite structures. The migmatitic gneisses represent end members in a transition system of gneisses and migmatites. The change from gneisses to migmatites and from one migmatite type to another takes place gradually, so that only artificial borders between the end-members can be defined (Figure 3-4). Figure 3-5 and Figure 3-6 show typical gneisses, migmatites and intrusive rocks at Olkiluoto.
Figure 3-4. Textural and structural end members in the migmatite - gneiss system of Olkiluoto (Kärki & Paulamäki 2006). 46
The migmatitic gneisses mostly comprise a mica-rich older component, or palaeosome, and a younger granitic component, or the neosome (also called leucosome). The migmatitic gneisses of Olkiluoto have been defined as rocks that include more than 10 – 20% leucosome. At Olkiluoto, they typically contain 20 – 40% leucosome on average, but the proportion can be less than 20% or in excess of 80% in individual samples.
The homogeneous, banded or only weakly migmatised gneisses include mica gneisses, mica-bearing quartz gneisses, hornblende- or pyroxene-bearing mafic gneisses and tonalitic-granodioritic-granitic gneisses. The mica-rich gneisses at Olkiluoto are, in general, intensively migmatised, but fine-and medium-grained mica gneisses with less than 10% leucosome material are also common (Figure 3-6). The fine-grained mica gneisses are typically schistose, but the medium-grained variants show a distinct metamorphic banding. Fine-grained, homogeneous and typically poorly foliated quartz gneisses contain more than 60% quartz and feldspars but 20% micas at most. Certain variants may contain some amphibole and in places some pyroxene in addition to amphibole. Garnet is also typical of some quartz gneisses. Mafic gneisses, in which hornblende or chlorite are the dominant mafic mineral, occur sporadically. Some mafic gneisses may exceptionally contain some pyroxene or olivine in addition to mica and hornblende. The tonalitic-granodioritic-granitic gneisses are medium-grained, relatively homogeneous rocks, which sometimes resemble plutonic, non-foliated rocks and sometimes coarse-grained mica gneisses (Figure 3-6). In places, they can also show a weak metamorphic banding or mylonitic foliation. The tonalitic-granodioritic-granitic gneisses form homogeneous and typically weakly fractured units. The contacts can be gradual varying in width from several tens of centimetres to several metres but they may sometimes resemble the sharp, intrusive contacts typical of igneous rocks. In places, leucosome-like granitic veins and cross-cutting pegmatitic granites comprise up to 20% of the volume of the gneisses but homogeneous rocks without any leucosome are also typical.
All the rock types mentioned above are very sharply cut by ca. NE-SW striking narrow diabase dykes, which dip steeply to the NW. The diabases are blackish and fine-grained and they contain quartz- and carbonate-filled amygdales, 0.1- 0.3 mm to ca. 2 mm in diameter. The diabases are composed of randomly oriented plagioclase laths in a thoroughly altered groundmass, so that no original mafic minerals are visible. The geochemical, petrological and U-Pb age data of the dykes (Mänttäri et al. 2005, 2006), and their cross-cutting relationships with other lithologies and the ductile deformation structures (Lindberg & Paulamäki 2004, Talikka 2005, Engström 2006, Paulamäki 2007) indicate that the Olkiluoto diabase dykes are probably Mesoproterozoic (ca. 1650 Ma) in age, or are at least younger than 1800 Ma. According to recent palaeomagnetic study by Mertanen (2007), the age of the diabase dykes is probably 1560 Ma. 47
A A B
C D
Figure 3-5. A) stromatic gneiss, B) and C) veined gneiss, D) diatexitic gneiss. Photographs by Seppo Paulamäki, Geological Survey of Finland. 48
A B
C D
E F
Figure 3-6. A) tonalitic-granodioritic-granitic gneiss, B) banded, weakly migmatised mica gneiss, C) quartz gneiss inclusions in the diatexitic gneiss, D) mafic gneiss, E) pegmatitic granite in the mica gneiss and F) diabase dyke sharply cutting the folded veined gneiss. Photographs by Seppo Paulamäki, Geological Survey of Finland.
On the basis of the whole-rock chemical compositions, the supracrustal rocks of Olkiluoto can be divided into four distinct series or groups: a T series, S series, P series and basic, volcanogenic gneisses (Kärki & Paulamäki 2006) (Figure 3-7), with T, S and P standing for Turbidite, Skarn and Phosphorus, respectively. In addition, pegmatitic granites and diabases form groups of their own that can be identified both macroscopically and chemically. The identification of the members of the different series is mostly based on the concentrations of phosphorus and calcium, their mutual ratios and their ratios to other elements. Ternary plots of calcium (Ca), phosphorus (P) 49
and aluminium (Al) or titanium (Ti) provide one basis for classification, as the members of the P series are enriched in phosphorus and the members of the S series in calcium (Figure 3-7 and Figure 3-8). Average mineral compositions and standard deviations of the rocks of the T, P and S series, pegmatitic granites, and metavolcanics are shown in Table 3-1. Differences are also visible in variation diagrams, which show the element oxide concentrations versus that of SiO2. Rocks of the T, S and P series are estimated to make up 42-46%, 7-12% and 26-28%, respectively, of the volume of central part of the island of Olkiluoto and the various pegmatitic granites about 20%.
Al2O3/5
T Series
S Series
P Series
CaO P2O5*10
Figure 3-7. Classification of the lithologies of Olkiluoto on the basis of whole-rock chemical analysis. Blue = T-series, orange = S-series, violet = P-series, red = pegmatitic granite, green = basic metavolcanic rock, black = diabase and + = penetratively altered gneiss or migmatite (Kärki & Paulamäki 2006). 50
Al2O3/5
4
1 5 O 2 P
0.1
40 50 60 70 80 CaO P2O5*10 SiO2
4 20 High-Ca
1 5
O 10 2 CaO P
0.1 Mafic Low-Ca 0 0.1 1 10 40 40 50 60 70 80
MgO+Fe2O3 SiO2 Figure 3-8. Ternary and binary plots used for chemical classification (Kärki & Paulamäki 2006). Explanation for the colours: blue = T-series, orange = S-series, violet = P-series, red = granite, green = mafic metavolcanic rock and black = metadiabase. Symbols: = mafic gneiss (S- or P-series), = veined gneiss, = diatexitic gneiss, = mica gneiss, = quartzitic gneiss, = TGG gneiss, metadiabase, = mafic metavolcanic rock, = leucocratic granite pegmatite, = cordierite bearing granite pegmatite, = garnet bearing granite pegmatite and = penetratively altered gneiss or migmatite. Low-Ca = low calcium subgroup of the S-series, high-Ca = high calcium subgroup of the S-series and mafic = mafic S type gneiss. Table 3-1. Average mineral compositions (AVG) and standard deviations (STD) of the rocks of the T, P and S series, pegmatitic granites, and metavolcanics (Kärki & Paulamäki 2006).
T series S series Mica Quartz TGG Mafic Low Ca High Ca Mineral Migmatites gneiss gneiss gneiss gneiss gneiss gneiss AVG STD AVG STD 1-samp AVG STD AVG STD AVG STD AVG STD Quartz 30.3 8.1 31.1 9.5 44.8 32.9 3.0 4.0 3.2 46.1 11.1 36.0 10.6 Plagioclase 17.0 8.3 17.3 7.1 21.4 23.2 5.9 12.4 8.5 31.6 10.4 25.7 13.5 K-feldsp. 8.6 7.4 6.4 3.7 16.4 20.0 9.0 0.2 0.2 0.3 0.2 0.1 0.2 Biotite 22.7 9.9 21.2 8.4 14.0 8.2 7.5 1.4 2.0 15.7 6.5 0.6 0.9 Muscovite 0.9 2.0 0.7 0.7 0.0 1.0 1.2 0.2 0.2 0.1 0.1 2.1 4.3 Hornblende 0.1 0.5 0.3 0.4 0.0 0.0 0.1 71.1 12.3 1.0 2.2 7.6 6.3 51 Pyroxene 0.0 0.1 0.1 0.2 0.0 0.0 0.1 0.2 0.2 0.0 0.1 1.6 3.7 Chlorite 2.6 5.3 3.8 5.2 0.0 1.7 1.9 0.5 0.2 0.5 0.7 0.3 0.3 Cordierite 4.0 4.8 0.9 1.6 0.0 0.0 0.1 0.2 0.2 0.4 1.1 0.1 0.1 Pinite 5.9 6.1 9.2 7.6 0.0 1.3 2.6 0.0 0.0 0.0 0.0 0.0 0.0 Garnet 0.0 0.0 0.1 0.2 0.0 1.2 3.6 0.2 0.2 0.4 0.6 1.4 1.3 Sillimanite 1.8 2.6 1.3 2.9 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0 0.0 Epidote 0.0 0.1 0.2 0.2 0.0 0.1 0.2 0.2 0.2 0.1 0.2 5.6 4.3 Sphene 0.1 0.2 0.2 0.2 0.0 0.1 0.1 0.3 0.2 0.0 0.1 0.9 0.6 Apatite 0.1 0.1 0.2 0.2 0.0 0.0 0.1 0.2 0.2 0.2 0.3 0.2 0.3 Saussurite 3.7 4.9 5.8 6.1 3.2 8.9 5.6 7.4 11.5 1.8 1.7 13.4 19.5 Sericite 0.8 1.8 0.3 0.4 0.0 0.6 1.8 0.3 0.4 0.1 0.3 3.1 4.2 Opaques 1.0 1.4 1.6 2.4 0.2 0.5 0.6 1.7 0.8 1.2 1.2 1.0 0.9
Table 3-1, continued.
P-series Metavolcanics Mafic Mica- Quartz TGG Mafic Mineral gneiss Migmatites gneiss gneiss gneiss Pegmatitic granite gneiss AVG STD AVG STD AVG STD 1 sample AVG STD AVG STD AVG STD Quartz 16.5 11.6 20.8 12.7 29.0 5.7 35.2 23.7 5.7 35.2 14.3 9.9 14.0 Plagioclase 33.9 8.5 22.6 16.6 35.1 6.3 0.0 34.4 8.3 16.7 8.5 2.3 1.6 K-feldsp. 0.3 0.3 6.9 8.4 0.2 0.2 0.0 11.5 10.9 32.8 17.6 0.0 0.0 Biotite 17.1 9.3 20.2 14.3 30.6 6.8 0.0 22.5 7.1 0.9 1.7 23.5 16.6 Muscovite 0.0 0.0 3.9 5.4 0.1 0.2 0.0 0.3 0.5 2.5 2.8 0.0 0.0 Hornblende 26.4 13.6 4.1 9.9 0.1 0.2 0.0 0.6 2.2 0.0 0.0 23.3 19.8 Pyroxene 0.0 0.0 0.1 0.1 0.1 0.2 0.0 0.1 0.2 0.0 0.0 3.4 3.5 52 Chlorite 0.0 0.1 3.7 8.3 0.6 0.4 0.0 0.3 0.5 0.7 0.9 20.6 29.1 Cordierite 0.0 0.0 0.2 0.3 0.1 0.2 0.0 0.1 0.2 0.1 0.4 0.0 0.0 Pinite 0.0 0.0 5.5 9.9 0.0 0.0 0.0 0.1 0.2 0.4 1.7 0.0 0.0 Garnet 0.0 0.0 0.1 0.1 0.1 0.2 0.0 0.4 0.8 0.4 1.0 0.0 0.0 Sillimanite 0.0 0.0 0.1 0.1 0.4 0.9 0.0 0.1 0.2 0.4 1.3 0.0 0.0 Epidote 0.2 0.5 0.1 0.1 0.1 0.2 0.0 0.1 0.2 0.0 0.2 0.0 0.0 Sphene 2.9 3.1 0.2 0.4 0.2 0.2 1.6 0.1 0.2 0.0 0.0 0.0 0.0 Apatite 3.4 1.2 2.1 3.2 1.6 0.7 0.8 1.1 1.0 0.0 0.1 2.0 1.3 Saussurite 2.8 1.4 2.3 2.8 1.6 1.2 62.2 4.5 3.7 7.5 5.9 0.3 0.4 Sericite 0.2 0.5 2.0 4.7 0.1 0.2 0.0 0.3 0.6 1.2 2.9 0.0 0.0 Opaques 1.3 1.5 0.9 1.3 0.9 1.0 0.2 0.5 0.6 0.4 0.5 2.1 2.5 53
The end members of the transitional T or turbidite series are often cordierite-bearing mica gneisses and migmatites that may have less than 60% SiO2, and quartz gneisses, in which the SiO2 content exceeds 75%. These compositions are quite typical of recent and ancient metasedimentary rocks of pelitic and greywacke origin, respectively. Consequently, these high-grade metamorphic rocks are assumed to originate from turbidite-type sedimentary materials. The end members of the T series have been assumed to have developed from clay mineral-rich pelitic materials and greywacke-type impure sandstones.
The members of the S or skarn series are quartz gneisses, mica gneisses and mafic gneisses. Homogeneous, often fine-grained gneiss layers, the thicknesses of which vary from tens of centimetres to several metres have been mapped in the drill cores, whereas in the outcrops concretions or roundish boudins differing in composition from the host rock represent the dominant types for this series. The members of the S series are assumed to have originated from calcareous sedimentary materials or to have been affected by other processes that produced the final skarn-type formations. The Ti/Mn/P ratios of the S series mafic gneisses are similar to those of island arc tholeites and the Zr/Ti versus Nb/Y ratios are similar to those of subalkaline basalts, indicating a volcanism-related process that has added magnesium and iron to the material mixture, which then metamorphosed to the S-type mafic gneisses.
The TGG gneisses are volumetrically the largest subgroup in the P or phosphorus series but the series also includes stromatic gneisses, diatexitic gneisses, mica gneisses and mafic gneisses. The characteristic feature of the members of this series is their high phosphorus content. The chemical composition of the TGG gneisses and texturally different mica gneisses and migmatites of the P series is so similar that it is not possible to separate them on the basis of their chemical composition. Thus, the TGG gneisses have been interpreted to be sedimentary in origin, rather than igneous rocks as believed in the early phases of the geological studies of Olkiluoto. The Zr/Ti versus Nb/Y diagrams of the P-type mafic gneisses resemble those for basaltic rocks, whereas Ti/Mn/P ratio shows similarity to the oceanic island andesites. Comparison of the chemical compositions of the different series indicates that the source material for the metasediments of the P series is probably the same kind of turbidite material as that of the T-type metasediments, which was mixed with material from picritic-type volcanic deposits, and was subsequently affected by physical and chemical enrichment processes that produced the final phosphorus-rich sediment material.
Basic metavolcanics resemble the mafic gneisses of the P series, but they are not identical. The alkali versus SiO2 ratios and the trace element concentrations are similar to those of high-magnesium basalts, and in some cases picrites or picritic basalts, indicating a subduction-related setting and volcanic arc affinity.
The migmatites and gneisses of turbiditic origin and the chemical character of the mafic gneisses at Olkiluoto indicate sedimentation and simultaneous volcanic activity in island arc environments. No age determinations of metavolcanics at Olkiluoto are available, but the depositional ages of Svecofennian supracrustal, volcanogenic rocks often range from 1910 to 1885 Ma (Welin 1987, Vaasjoki et al. 1994, Kähkönen 1999, Väisänen et al. 2002, Ehlers et al. 2004).
Abundant coarse-grained felsic rocks of granitic composition, in the form of veins, vein networks and irregular masses, are a typical feature of the Olkiluoto bedrock. A vast majority of these rocks, referred to as pegmatitic granites, are coeval with the ductile 54
deformation and migmatisation processes, being genetically strictly associated with the leucosome generation processes. Post-migmatitic, crosscutting, real pegmatite dykes from external sources have very rarely been observed (see Paulamäki 2005a, b). The trace element ratios for the pegmatitic granites indicate generation in a volcanic arc environment and they have been thought to be generated by partial melting of metasedimentary rocks as a result of isothermal decompression in the late stage of orogeny (see e.g. England & Thompson 1984). An isochemical character for the migmatisation process is supported by the similarity in chemical composition between homogeneous gneiss relicts and the corresponding migmatites, which can contain up to 40 – 50% leucosome. This means that the loss of anatectic melt from the migmatite system was minimal. However, subsequent injection of granitic magmas from an external source is possible, and most probably at least some of the largest pegmatitic granites of Olkiluoto have been generated in that way. The minimum intrusion age of the pegmatitic granite cutting the TGG gneiss in the Ulkopää area, west of the Olkiluoto site, has been determined to be 1823±3 Ma (monazite age), the maximum age being ca. 1.86 Ga (Mänttäri et al. 2006).
The mineral assemblage of the T-type gneisses is typical of metapelites of the cordierite-biotite-sillimanite-K-feldspar zone of prograde metamorphism. Under the conditions indicated by the metamorphic mineral assemblages typical of Olkiluoto, the processes that may have caused the melting of pelitic and greywacke-type materials are H2O-fluxed melting, near-isothermal decompression and dehydration melting. It can be estimated that in the then prevailing metamorphic system, the temperature capable of producing the migmatite structures and metamorphic mineral assemblages found at Olkiluoto is ca. 650 – 700 oC, representing the conditions of the uppermost amphibolite facies at pressures of ca. 3 – 4 kb (Kärki & Paulamäki 2006).
The rocks were most likely metamorphosed for the first time during deformation phase D2 (see Chapters 3.2.2 and 3.3.2). Väisänen (2002) relates the D1/D2 deformation and associated metamorphism in SW Finland to a collision between two Svecofennian arc complexes, which would have taken place at 1880-1860 Ma. At Olkiluoto, the recent datings has given a U-Pb age of 1863±3 Ma for the tonalitic gneiss of Ulkopää, which hosts the repository of low-and intermediate level waste (Mänttäri et al. 2006). A similar age is reported by Suominen et al. (1997) from the Lähteenmäki tonalite ca. 16 km SE of Olkiluoto in the Rauma 1:100 000 map sheet area. At Olkiluoto, where the tonalitic-granodioritic-granitic gneisses have been interpreted as metasediments, this age may be related to anatexis during the early high-grade metamorphism.
In the Turku area, 100 km south of Olkiluoto, the peak of the later metamorphism is dated at 1824±5 Ma on the basis of the garnet and cordierite-bearing leucosome, constraining the age of the regional anatexis (Väisänen et al. 2000; Väisänen 2002). Väisänen et al. (2000) have obtained a U-Pb age of 1814±3 Ma for garnet bearing S- type granite in Masku in SW Finland. Kurhila et al. (2005) report ages ranging from 1850 Ma to 1820 Ma for migmatising microcline granites in SW Finland. These ages are in good agreement with ca. 1820 Ma metamorphic age of a structurally homogeneous zircon from the TGG gneiss and the minimum age (1823±3 Ma) of the pegmatitic granite at Olkiluoto (Mänttäri et al. 2006). Furthermore, in 1:100 000 Rauma map sheet area, the Lähteenmäki tonalite has a monazite with a U-Pb age of 1813±4 Ma indicating timing of metamorphism (Suominen 1991). Väisänen (2002) relates the metamorphism to the period of crustal shortening of the Svecofennian orogen (corresponding to the Svecobaltic orogen of Lahtinen et al. 2005). 55
3.3.2 Ductile deformation
The bedrock of Olkiluoto belongs to the Svecofennian domain of Southern Finland, which was deformed in a ductile manner during the Fennian and Svecobaltic orogenies (Lahtinen et al. 2005, Section 3.2.3). Structural sequences which resemble the sequence determined from the Olkiluoto site are described from the Uusikaupunki area, south of Olkiluoto (Selonen & Ehlers 1998) and the Loimaa – Alastaro region (Nironen 1999), westward of Olkiluoto. Features created by ductile deformation at Olkiluoto may be highly synchronous with those of the adjacent regions but exact correlation is impossible without direct age determinations of the deformation processes. In the same way, the intensities of individual deformation processes vary markedly in different subareas making direct connections impossible.
At Olkiluoto, the lithological layering (S0) and weak foliation (S1) created by the first stage of deformation are often detectable, (sub)parallel, and represent the oldest observed structural elements. Relicts of primary bedding structures such as graded bedding in metaturbidite sequences can be observed (Figure 3-9A). The primary bedding may also be reflected by different degrees of migmatisation in different parts of thick turbidite sequences, in which the pelitic, mica-rich parts may be strongly migmatised, whereas the psammitic parts are often better preserved. Mafic or ultramafic layers of metavolcanic rocks can be visible as chains of dark boudins within the metapelites. Similarly, S-type quartz gneisses may occur as blocks or boudins of variable size. In Vähä-Kaunissaari, ca. 3 km east of the site, thin (10 cm wide) calcareous interbeds can be followed for tens of metres (Paulamäki 2007).
Structural elements of the first deformation phase (D1) have been distinguished only sporadically at the hinges of later isoclinal, intrafolial folds (Figure 3-9B, C). S1 foliation can be detected as a medium-grained schistosity or weak metamorphic banding parallel to primary lithological layering. In turbiditic materials this foliation may be well-developed in the pelitic sublayers but typically not visible in the psammitic parts. Under the microscope, the strike of this foliation is, in places, manifested by inclusion trails within large porphyroblasts (Paulamäki 2007). Undeniable F1 fold structures are not recognized, but in places tight to isoclinal fold structures are observed which have been tentatively interpreted as F1 elements (Paulamäki & Koistinen 1991, Paulamäki 2007). Fold structures of well-preserved turbidite beds shown in Figure 3-9D presents one example of those. However, structural elements created by the earliest deformational events are rarely identifiable thus making it difficult to evaluate their exact significance. 56
S2
S1
A B
S1
S1 S2
S1/2 C D
Figure 3-9. A) Primary bedding structure in the turbiditic mica gneiss. B) Weak S1 foliation in the psammitic quartz-feldspar gneiss folded by F2 with axial planar foliation S2. C) Biotite foliation S1 folded by F2 with axial planar foliation S2. D) S1 foliation folded by possible F1 fold with no axial planar foliation. The length of the scale is 21 cm (A) and 12 cm (C-D). Photographs by Seppo Paulamäki, GTK.
Subsequent deformation phase D2 is characterised by intense, most probably thrust- related deformation associated with strong migmatisation. In this deformation phase, tight or isoclinal, often intrafolial F2 folds formed and most probably their axial surfaces were subhorizontal due to overturning. Penetrative axial plane foliation (S2) is typically metamorphic banding, which is coplanar with abundant D2 leucosomes (Figure 3-10A). Due to the tightness of F2 folds and intensity of D2 deformation, the relicts of lithological layering and earlier foliations have often been rotated parallel to the S2 foliation, which can, in fact, be expressed as a composite structure S0/1/2. S1 foliation can be separated from S2 only at the hinges of some F2 folds (Figure 3-9B, C).
Metatexitic migmatites (veined gneisses and stromatic gneisses) show a wide range of pervasive deformation textures. Typical foliation in the paleosome of stromatic gneisses is well-developed, planar metamorphic banding with parallel neosome dykes (Figure 3-10B). Foliations in the veined gneisses are more irregular and, shear-related lineations are often detectable. Dark, mica-rich bands in these rocks are undulating, mostly discontinuous and they rim the elongated leucosome veins (Figure 3-10C). Diatexitic gneisses are more strongly migmatised and the proportion of leucosome is larger in them. Typical foliation developed in these rocks is defined by biotite-rich schlieren or melanosomes, whereas in the nebulitic migmatite types the foliations are barely 57
observable (Figure 3-10D). The typical foliation detected in the TGG gneisses is medium-grained gneissosity often associated with strong lineation (Figure 3-10E). The intensity of foliation varies from place to place and it is possible to find igneous looking, poorly foliated gneiss types in this assemblage. In the TGG gneisses, this foliation is the earliest detected structural element although it is evolved during the D2 stage of regional deformation.
In the course of progressive D2 deformation the production of leucosome continued and the veins formed at an early stage of deformation were sheared semiconcordantly and accompanied by isoclinal folding (Figure 3-10F). Shear-related structures have been observed as the most important D2 elements in some zones, where veined gneisses are dominated by asymmetric augen structures and the migmatites, on the whole, are strongly sheared. In general, D2 deformation is assumed to be the most intense stage in the structural evolution of the Olkiluoto domain, and most of the present appearance of the migmatitic rocks was reached then. It has pervasively deformed the whole paragneiss complex simultaneously with metamorphism under the amphibolite facies conditions. Thus, it is possible to interpret most of the structural elements as some kind of composite or interference structures with the products of D2 deformation. The age of the D2 stage is estimated to be 1880-1860 Ma based on the age of the TGG gneisses (see Section 3.3.1).
Well-preserved D2 structures may occur in more competent rock units within the migmatite complex. Likewise, several rather wide subdomains, where D2 is estimated to be the most important structural factor, seem to be preserved in spite of the later deformations. Accordingly, the western and south-eastern parts of the Olkiluoto study area are the most potential localities to find less-disturbed D2 structural features. Foliations dipping to the S-SW within these subareas (Figure 3-11) may indicate lower intensity of latter deformations. 58
A B
C D
E F
Figure 3-10. A) Penetrative S2 foliation defined by metamorphic banding, which is coplanar with D2 leucosomes. The folding and axial planar leucosome belong to deformation phase D3. B) Stromatic gneiss with foliation-parallel D2 leucosome veins. C) Veined gneiss, which is sheared conformably to S2 foliation. D) S2 foliation in diatexitic gneiss defined by abundant leucosome veins and biotite schlieren. E) Gneissic S2 foliation in TGG gneiss. F) Shear-related (D2) isoclinal folding of D2 leucosome veins. The length of the scale is 21 cm (A, B), 12 cm (D, F), 11 cm (E) and 15 cm (C). Photographs by Seppo Paulamäki, GTK.(A, B, D,F) and Jussi Mattila, Posiva Oy (C). 59
Figure 3-11. Stereograms showing orientation of foliations measured from surface and drill cores down to the depth of –250 m in selected subareas of the Olkiluoto site.
In deformation phase D3, the earlier deformed migmatites were zonally refolded, rotated or sheared. Zones dominated by ductile D3 shear structures and tight F3 folds were formed, and often the D2 structures were often rotated parallel to the F3 axial surface (S3) striking to the NE and dipping to the SE.
F3 folds are typically close to tight and also chevron-type folds are also common (Figure 3-12). They have been observed all over the study site but the major zone dominated by these elements is located in the central part of the site. F3 fold axes often plunge gently to the NE or SW (Figure 3-13A) and axial planes dip to the SE (Figure 3-13B). S3 axial surfaces are gently SE dipping in the central part of the site but become steeper in the southern and south-eastern parts. Observed dimensions of the F3 folds vary from a few centimetres up to several metres (Figure 3-12). Pervasive axial surface foliation or crenulation was seldom developed even at the hinges of tight F3 folds, but in the zones strongly affected by D3 deformation, S2 and S3 foliations cannot be separated because S2 60
foliation has more or less rotated into parallelism with the F3 axial surfaces (S3), so that the foliations in this case can be classified as S2/3 composite structures on the basis of their orientation and geometrical relation with the F3 fold structures. At least in places, it may be possible to distinguish S3 foliation from S2 on the basis of differences in meso- and microscopical features but to date, no such a work has been performed.
D3 shear zones are thrust zones parallel to the F3 axial surfaces (Figure 3-12I) or E-W striking oblique-slip shear zones. Observed shear zones parallel to F3 axial surfaces are characterised by shear bands of blastomylonitic fault rocks (Figure 3-12J) and asymmetric, intrafolial folds. Within these shear bands blastomylonitic foliation defined as S3 foliation totally overprints all the earlier structures and S3 foliation is often developed as a transposition structure. Dextral shear structures dominate the area of the E – W striking Selkänummi Shear Zone (SNSZ) which, in its totality, is interpreted as an oblique-slip shear zone, of which SE- plunging stretching lineations and southward dipping blastomylonitic foliations are characteristic (Figure 3-124K). The position of the roughly E-W striking Liikla Shear Zone (LSZ) in the southern part of the Olkiluoto area was previously based on interpretation of ground geophysical data, but recently it has been confirmed by investigation trench TK14 (Figure 3-124L, Nordbäck, in prep.). The detailed results of the trench mapping have not been available during the making of this model.
Simultaneously with D3 deformation new granitic leucosomes and cogenetic pegmatite dykes or migrated leucosomes intruded often parallel to the F3 axial surfaces and shear structures (Figure 3-12). Large pegmatitic granite bodies parallel to D3 shear zones (see Appendix XII) may be a result of the intrusion of leucosome melt into the transtensional environment associated with D3 deformation. The approximate age of the D3 deformation at Olkiluoto is 1860-1830 Ma based on the U-Pb (SIMS) age of one D3 related pegmatitic granite dyke (with a maximum age of 1860 Ma and a minimum age 1823 Ma) cutting the 1863 Ma TGG gneiss in the Ulkopää area, western part of Olkiluoto (Mänttäri et al. 2006).
The intensity of D3 deformation is highest in the central part of the site and within the E-W striking ductile shear zones in the northern and southern parts of Olkiluoto. Diagrams showing orientations of all foliations measured from outcrops and drill cores are presented in Figure 3-11. Bedrock volumes dominated by SE dipping foliations are mostly located in the central part of the Olkiluoto site, whereas southward dipping foliations dominate the bedrock unit intersected by the Selkänummi Shear Zone in the northern part of Olkiluoto (Figure 3-11). 61
F3 axial surface
F3 axial surface
S0/S1/S2
A S0/S1/S2 B
F3 axial surface
F2 axial surface
S2
F2 axial surface
C D
S2
F3 axial surface
E F
Figure 3-12. A) Large-scale F3 fold with pegmatitic granite leucosome in the hinge zone of the fold. Island of Kuusisenmaa. B) Large-scale F3 folding. Island of Pask- Aikko. C) Overturned F3 fold. Road-cut 5 km E of Olkiluoto. D) S2 foliation and isoclinally folded D2 leucosome veins refolded by F3. E) Tight F3 folding with S2 almost parallel to the axial surface of F3. Island of Kovakynsi. F) Tight F3 folding with D3 stretching lineation. ONKALO access tunnel. The length of the scale in D and E is 12 cm. Photographs by Seppo Paulamäki, GTK (A-E) and Aulis Kärki, Kivitieto Oy (F). 62
D3 leucosome D3 pegmatitic S2 granite
F3 axial surface F3 axial surface
S2
G H
I J
K L
Figure 3-12 (cont’d): G) F3 folding with axial planar leucosome veins. H) F3 folding with axial planar pegmatitic granite dyke. I) Axial planar D3 shear zones. J) D3 shear zone in the wall of the ONKALO acces tunnel chainage 1450.50 m. K) D3 shearing, the Selkänummenharju shear zone. L) D3 shearing, the Liikla shear zone. The length of the scale is 21 cm (A, B) and 12 cm (C). Photographs by Aimo Kuivamäki, GTK (G), Seppo Paulamäki, GTK (H-I), Aulis Kärki, Kivitieto Oy (J-K) and Antero Lindberg, GTK (L). 63
A)
B)
Figure 3-13. Orientation of F3 fold axis (A) and axial planes (B) measured in outcrops and in the investigation trenches. Equal area, lower hemisphere projection.
Subsequently, D3 elements and earlier structures were again redeformed in deformation phase D4, which produced close to open F4 folds with axial planes striking to the NNE and dipping to the ESE (Figure 3-14). The outcrop and trench mappings indicate that the central and south-eastern parts of the Olkiluoto site, the ONKALO area and the region extending ca. 500 m eastward from it, have been affected more strongly by D4. Due to D4 deformation, the D2/3 interference structures were zonally reoriented towards the orientation of the F4 axial surfaces (S4) and close to open F4 fold were created (Figure 3-15A-F). The mean orientation of the S4 in surface section is 110/45 on the basis of measurements carried out from outcrops and drill core samples but the S4 surfaces bend to a more gentle orientation in the deeper parts of bedrock (Figure 3-11). N-S striking pegmatitic granite dykes, which cut F3 folding, occur here and there but their relation to F4 folding is not quite clear (see Paulamäki 2007). In places, ductile D4 shear zones, subparallel to the regional direction of S4, have been observed (Figure 3-15G-J) and the thicknesses of these shear zones or bands vary from a few centimetres to several metres. In visual observation, D4 fault rocks seem to represent lower- grade metamorphic conditions than the elements associated with earlier deformations but at the moment no detailed studies of fault rock petrography or metamorphic evolution 64
have been done. At least a part of intrusive-like rocks named at Olkiluoto as K-feldspar porphyries (Mattila 2006) seem to be related to D4 shear zones (Figure 3-15K-L) (Paulamäki & Koistinen 1991, Paulamäki 2005, Mattila et al. 2007). The age of the D4 stage at Olkiluoto is estimated to be less than 1830 Ma, i.e., this deformational event took place during the Svecobaltic orogeny (see Lahtinen et al. 2005).
a)
A)
B)
Figure 3-14. Orientation of F4 fold axis (A) and axial planes (B) measured in outcrops and in the investigation trenches. Equal area, lower hemisphere projection. 65
F4 axial surface F4 axial surface
F3 axial surface
S2 S2
A B F3 axial surface
F3 axial surface
F4 axial surface
F4 axial surface S2
F3 axial surface
S2 C D
E F
Figure 3-15. A and B) S2 foliation folded by tight F3 folding and refolded by more open F4 folding. C and D) Outcrop-scale fold structure, in which tight F3 folding is refolded by more open F4 folding. E and F) Tight F3 folds reoriented towards the orientation of the F4 axial surfaces. The length of the scale is 12 cm. Photographs by Seppo Paulamäki, GTK (A-D) and Aulis Kärki, Kivitieto Oy (E-F). 66
G H
S4 S4
F3
S2 I G J
S2
D4 shear zone
K-feldspar porphyry K-feldspar porphyry
K S4 L
Figure 3-15 (cont’d). G) D4 shear zone above the ONKALO access tunnel with rotated K-felspar porphyroclast and boudined leucosomes showing sinistral sense-of-shear. H) Winged inclusion in D4 shear zone above the ONKALO access tunnel showing sinistral sense-of-shear. I) D4 shear zone with blasmylonitic foliation (S4) has a mica gneiss palaeosome fragment with S2 foliation folded by F3. Rotated K-felspar porphyroclasts or boudined leucosome indicates dextral sense-of-shear. Accommodation village N. J) D4 shear zone on the wall of the ONKALO access tunnel. K) K-feldspar porphyry related to D4 shear zone. Accommodation village N. L) Deflection of the foliation planes towards the K-feldspar dyke indicating apparently dextral sense-of-shear (Mattila et al. 2007). OL-TK11. The length of the scale is 12 cm. Photographs by Seppo Paulamäki, GTK (G-I, K), Aulis Kärki, Kivitieto Oy (J) and Jussi Mattila, Posiva Oy (L). 67
Probably the youngest stage of ductile deformation is D5 as defined by Paulamäki & Koistinen (1991) and Paulamäki (2007). Open fold structures with steep axial planes striking to the SE and fold axes often plunging in the same direction (Figure 3-16) have been interpreted to be products of this stage. These fold structures can be detected as small flexures or outcrop-scale undulation of previous planar elements (Figure 3-17).
A)
B)
Figure 3-16. Orientation of F5 fold axis (A) and axial planes (B) measured in outcrops and in the investigation trenches. Equal area, lower hemisphere projection. 68
F5 axial surface
A B
S2 F5? D5 axial surface F5 axial surface
F3 axial surface
C D
Figure 3-17. A) F5 defined by outcrop-scale undulation of the previous structural elements. B) Fragment of an amphibolite dyke in diatexitic gneiss openly folded by F5. C and D) F5 defined by small flexures with a strong lineation. The length of the scale is 21 cm in A-C and 12 cm in D. Photographs by Seppo Paulamäki, GTK.
Geophysical indications of ductile deformation structures are indirect. Petrophysical data indicate that magnetic susceptibility is not directly controlled by different rock types. However, the most significant magnetic anomalies are related to ferrimagnetic, pyrrhotite-bearing gneisses (veined gneisses, mica gneisses, diatexitic gneisses). The main granitic units are typically located between these units. Magnetic 3D profile interpretation indicates that the dips of the magnetized units become gentler with depth, agreeing well with the foliation observations in the drillholes (Figure 3-18).
A S2 69
Figure 3-18. Magnetic profile interpretation.
The most recent interpretation of the horizontal-loop electromagnetic (HLEM) ground survey indicates clear trends, corresponding with structural features created by deformation phases D2 and D3 (Paananen et al. 2007) (Figure 3-19, Appendix II). In the north, the directions of the electric conductors bounding the main TGG gneiss unit at Selkänummenharju are almost E-W, locally corresponding to the S2 direction and D3 shear structures therein. The calculated inphase-quadrature ratios indicate that these conductors are sulphide- or graphite-rich zones, located at or near the contacts of the TGG gneiss unit. Elsewhere, the main trend is ENE-WSW corresponding to the S2/3 direction, and the conductors are slightly weaker. It is probable that most of these conductors still consist of conducting minerals (sulphides, graphite), but a portion of the electrical anomalies may be affected by thickening and elevated moisture of the overburden as well as fracturing in the bedrock.
In Figure 3-19, the interpreted HLEM conductors are presented on a magnetic ground survey map. At several locations, the conductors appear to bound or coincide with the magnetic anomalies. The white lines parallel to planar D4 elements represent non- conducting features that have been traced according to the discontinuities of conductors parallel to the D2 and D3 planar structural elements. They may be brittle by nature, but they also may be indications of ductile shearing associated with the D4 deformation.
Structural interpretation map of Olkiluoto Island is shown in Appendix XII. 70
Figure 3-19. Interpreted HLEM conductors, black lines (Paananen et al. 2007) on a magnetic map. Crosscutting D4-trending features are depicted by white lines.
3.3.3 Brittle deformation
In this chapter, a brief summary of the tectonic events after the Fennian and Svecobaltic orogens within and at the margins of the Fennoscandian Shield is given, as these events have most likely had an influence on the bedrock of Olkiluoto. A more thorough description of the analysis of the faults at Olkiluoto is given in Appendix III. The brittle evolution of the Olkiluoto Island is shown schematically in Figure 3-20.
1) 1830-1650 Ma: Contraction and thrusting related to the Fennian or the Svecobaltic orogen
As the crust cooled after (or partly during) the D4 stage, the ongoing thrusting that formed the low-angle D4-shears were reactivated in the brittle regime during NW-SE compression, producing many of the site-scale fault zones at Olkiluoto. The faulting is likely to have been started as semi-ductile to semi-brittle deformation, and turned into truly brittle at later phases.
Whether the thrusting is associated with the Fennian or the Svecobaltic orogen is unknown and further analysis is needed to resolve this. Still, it is clear that faults already existed at the beginning of the 1650-1550 Ma extension. 71
In the Jurmo-Sottunga area in southwestern Finland, Torvela (2007) reports the formation of mylonites and ultramylonites around ca. 1790 Ma, which were reactivated at least once between ca. 1790 Ma and 1580 Ma.
2) 1650-1550 Ma: Extensional tectonics related to emplacement of the rapakivi granites
The rapakivi batholiths were emplaced during an extensional tectonic regime. According to Korja and Heikkinen (1995) and Heikkinen et al. (1998), extensional tectonics caused thinning of the crust via listric shear zones, which resulted in the development of a block structure in the upper part of the crust. The subsequent upwelling of the mantle caused the partial melting of the upper mantle, mafic underplating of the thinned crust, and partial melting of the lower crust. A thermal dome was developed in the upper crust due to the heat of the rapakivi magmas. With the cooling of the extended crust and mantle, and the rapakivi magma underlying the dome, the crust began to subside, and the sedimentary basins (e.g, the Bothian Sea basin and the Satakunta graben) grew and filled, when the thermal dome was eroded. During the extensional tectonics, the bedrock at Olkiluoto was deformed in a brittle fashion. The emplacement of the rapakivi granites at ca. 1580-1550 Ma triggered hydrothermal activity and hot fluids started to circulate in the existing fractures, causing hydrothermal alteration (Blomqvist et al. 1992, Paulamäki et al. 2006). In a detailed mineralogical study of the fracture zone at 613-618 m in drillhole OL-KR1, Blomqvist et al. (op. cit.) have recognised a total of 21 fracture infillings, which they classified into five groups according to decreasing temperature and age. They defined two hydrothermal groups, the older one, characterised by muscovite-greisen fractures, silicified microbreccias, albite veins and quartz veins, is considered to be associated with the emplacement of the rapakivi batholith.
Within the Eurajoki rapakivi stock, hydrothermal fluids, migrating in interstices and fractures of the rapakivi granites have caused greisen veins (Haapala 1977). The greisen veins both in the Tarkki and Väkkärä granite were formed by fluids emanated from the Väkkärä granite. Greisen veins have also been encountered outside the rapakivi stock in Olkiluoto and its near surroundings (Paulamäki 1989, 2007).
At this stage (1560 Ma), diabase magma was intruded in subvertical fractures striking NE-SW and E-W (see Chapter 3.3.1).
3) Ca. 1300-1100 Ma: Extensional period related to the onset of the Sveconorwegian orogeny The olivine diabase dykes and sills of the Satakunta area dated at 1270-1250 Ma and the related dykes and sills in Sweden, Greenland and Canada, reflect the tensional tectonics and the break up of the Baltica/Laurentia supercontinent (Elming & Mattsson 2001) at the onset of the Sveconorwegian orogeny (Starmer 1993). Nearly coeval with these diabase dykes are ca. 1180 Ma old mafic dyke swarms associated with the Protogine Zone in southern Sweden (Johansson & Johansson 1990).
The rifting gave rise to a system of rifts and aulacogens both along the margins and in the interior of the craton (Nikishin et al. 1996). Nikishin et al. (op. cit.) argue that the Gulf of Bothnia rift, including the Satakunta and Muhos Grabens, Bothnian Sea Basin and the Bothnian Bay Basin, started at that time but, as described above, its development may have started already earlier due to rifting in connection with the 72
emplacement of the rapakivi batholiths ( see e.g. Korja & Heikkinen 1995). In connection with rifting and the intrusion of diabase magma, block movements occurred after the deposition of the upper parts of the sandstone, as evidenced by the tilted sandstone beds in the northeastern part of the graben (Laitakari 1983, Kohonen et al. 1993). Faulting after the deposition is further supported by the coarseness of the upper part of the sandstone, indicating rapid deposition and high relief (Kohonen et al. 1993).
In the fracture zone at 613-618 m in drillhole OL-KR1, the younger hydrothermal group, characterised by clay minerals, especially illite, crystallised on chlorite shear planes and fractures, have been related to this stage (Blomqvist et al. 1992). The three illite samples dated (Rb/Sr), gave ages of 1031 Ma, 1353 Ma and 1365 Ma. In the ONKALO area, the illites of the fault zone OL-BFZ100 (Paulamäki et al. 2006) have yielded K-Ar ages 1384 Ma and 1372 Ma (Mänttäri et al. 2007). Taking into account the effect of the detrital K-feldspar contamination in clay frations, which tend to increase the ages (Mänttäri et al. 2007), the latter ages may indicate movements related to olivine diabase magmatism.
The main phase of the Sveconorwegian orogeny (the collision between Baltica and Laurentia cratons) took place ca. 1100 - 950 Ma ago (Starmer 1993). The late Sveconorwegian extension resulted in extensive rifting. The 700 km long and 150 km wide ca. NNE-SSW striking Blekinge-Dalarna dyke swarm, dated at ca. 930 Ma, is related to the late Sveconorwegian extensional uplift. In SW Finland low-altitude aeromagnetic maps suggest that the 1250 - 1270 Ma old olivine diabase dykes are cut by N-S trending aeromagnetic anomalies, which have been interpreted as a swarm of diabase dykes (Vorma & Niemelä 1994, Veräjämäki 1998). These dykes are not exposed but according to drilling observations they are 1 to 5 m wide and, contrary to the olivine diabase dykes and sills, often weakly porphyritic (Laitakari 1998). The age of the dykes is still unknown but their different mode of occurrence suggests that they are considerably younger than the olivine diabases (Amantov et al. 1996). Whether these dykes are comparable to the Sveconorwegian dykes in Sweden or are related to some other event, remains to be solved.
The strike-slip faults at Olkiluoto are constrained to have formed 1560-1270 Ma ago, based on crosscutting relations and isotopic analysis (see Appendix III), but their relation to the extensional regimes at 1650-1100 Ma is yet unsolved and requires further studies. It is noteworthy to mention that no publications dealing with the existence of faults at the Satakunta region of this age and type exists, yet clearly these faults play an important role, spatially at least, in the Olkiluoto region. The strike-slip faulting also reactivated the existing thrust faults, superimposing horizontal slip lineations on to the faults (see Appendix III). 73
Figure 3-20. Schematic representation of the brittle deformation at Olkiluoto from 1850 Ma onwards. (A) Crustal shortening and thrusting at approximately 1850-1830 Ma to 1560 Ma; (B) Extension at 1560 Ma and the intrusion of diabase dykes; (C) Formation of strike-slip faults and reactivation of older structures at approximately 1560-1270 Ma; and (D) Extension during or after 1270 Ma and reactivation of existing structures. Thick black arrows indicate the direction of maximum crustal contraction or extension and thin arrows the sense of movement. See text for further explanation. View from above, the top of the Figure is towards the north. For details, see Appendix III.
4) The Neoproterozoic exhumation stage c. 900-600 Ma (definition by Kohonen & Rämö 2005)
After the Sveconorwegian orogeny, Laurentia and Baltica cratons together with all the other continents formed one single worldwide supercontinent, called Rodinia. Within the Baltica craton, extensional tectonics and intracratonic basin evolution was initiated ca. 800 - 750 Ma ago and aulacogens, rift basins and continental depressions formed 74
within the craton from Ukraine to Scandinavia, an example of which is the Vättern Graben in SW Sweden (Kumpulainen & Nystuen 1985, Vidal & Moczydáowska 1995). The further development of the Bothnian Sea basin is suggested by van Balen & Heeremans (1998) to be related to Neoproterozoic development of intracratonic basins by asthenospheric upwelling.
In the Bothnian Bay, reactivation of the NW-SE faults (in the Senja-Oulunjoki Tectonic Zone) is interpreted to have taken place ca. 650 - 600 Ma ago, related to the rifting and opening of the Iapetus Ocean between Baltica and Laurentia (Wannäs 1989). The extensional tectonic regime after the initial opening of the Iapetus Ocean is also manifested by alkaline magmatism, represented by the Alnön complex on the western shore of the Bothnian Sea in Sweden and the Fen complex in southern Norway (Meert et al. 1998). The kimberlites in eastern Finland, dated at ca. 600 Ma (Peltonen et al. 1999) may be related to this tectonic stage.
It is suggested by Kohonen & Rämö (2005) that gradual uplift and erosion with local subsidence and deposition characterise this stage in Finland. At Olkiluoto, illite of the brittle fault zone in chainage 65.60-65.75 m in the ONKALO access tunnel has a K-Ar age of 911 Ma (Mänttäri et al. 2007) indicating reactivation of pre-existing faults during this period.
5) The stage of platform sedimentation c. 600-420 (definition by Kohonen & Rämö 2005)
The Cambrian clastic dykes found in various places in Finland and Sweden are considered to mark intracratonic tectonic activity under an extensional regime. In the rapakivi area of the Åland Islands, the older Lower Cambrian dykes are mainly vertical and dominantly strike 0- 20°, while the younger Lower Cambrian dykes strike 40 - 160° (Bergman 1982). According to Bergman (1982) the fractures have opened after the sedimentation. The lack of Middle Cambrian dykes indicate that the main tectonic events took place in the Lower and Upper Cambrian. The clastic dykes also penetrate the weathered crust and hence were originally very deep (Bergman 1982). Bergström & Gee (1985) suggest that various episodes of transgressions and regressions in the Lower Cambrian sandstones and the Middle and Upper Cambrian shales may be related to local crustal instability. According to Artyuskov et al. (2000) vertical crustal movements with an amplitude up to several hundreds of metres may have taken place in the East Baltic and southern Sweden in the Cambrian and early Ordovician. Andersson et al. (1985), however, see that the bedrock was very stable in the Middle Cambrian to Lower Ordovician, as evidenced by thin deposits of alum shales, representing long and very slow deposition.
In Olkiluoto, illite of the brittle fault zone in chainage 70.00-71.90 m in the ONKALO access tunnel has a K-Ar age of 549 Ma (Mänttäri et al. 2007) and possibly represents movements during this stage.
6) The Caledonian foreland stage c. 420-350 Ma (definition by Kohonen & Rämö 2005)
The extent of influence of the Scandinavian Caledonides east of the orogen is poorly understood and speculative. According to Muir Wood (1995) the influence may have been rather modest, since the thick crust of the Fennoscandian Shield may have prevented the propagation of movements to the inner parts of the shield. On the other 75
hand, the majority of the linear features in Estonia, Latvia and the St. Petersburg region in Russia are considered to be related to late Caledonian compressional movements (Puura et al. 1996). As a result of these movements the area was uplifted, slightly tilted (ca. 0.1° in a SSE direction) and gently faulted (Puura et al. 1999).
A forebulge axis migrating with time and developed on the periphery of the Caledonian foreland basin by flexing of the lithosphere, may have been located along the Gulf of Bothnia during the late Silurian-Early Devonian (Tullborg et al. 1995). In the Bothnian Sea Basin, the Cambrian to Ordovician sedimentary sequences are rather undisturbed, but block faulting and associated flexural folding can be noticed in some of the reflection profiles (Winterhalter 1972, Axberg 1980). Three major tectonic zones are found both in the Bothnian Sea and onshore; two NW-SE trending zones and one, the Bothnian Zone, extending northward along the Swedish coast to the northernmost part of the Gulf of Bothnia (Axberg 1980). The faults are, however, originally Precambrian in age (Winterhalter 1972), and they were reactivated during the Caledonian orogeny in the Silurian. In the Bothnian Bay, downfaulting of the Cambrian sequence, which protected it from erosion, was most likely related to movements in the Caledonian orogen (Wannäs 1989).
The continent-continent collision in the Silurian was followed in the Devonian by uplift and denudation of the Caledonides. Probably up to 4 km of sediments deposited on the Caledonian foreland basin east of the orogen (Tullborg et al. 1995, Cederbom et al. 2000). Based on apatite fission track results from the samples from Åland, Olkiluoto, Kivetty and Romuvaara, it is likely that most of Finland was buried by sediments that thinned to the east (Larson et al. 1999). The southern Satakunta area was probably covered by ca. 1 km thick pile of sedimentary rocks. The Devonian, post-Caledonian tectonics are characterised, especially in western and southern Norway, by major extensional detachments and extensional reactivation of major shear zones (Fossen & Rykkelid 1992, Hurich 1996, Milnes et al. 1997, Andersen 1998, Fossen & Dunlap 1998). In north-eastern Finland, the Sokli carbonatite complex and Iivaara complex dated at 380 - 360 Ma (Kramm et al. 1993) belong to this stage.
In Småland, SE Sweden, the block faulting is regarded as post-Silurian in age (Milnes et al. 1998). The faults are normal faults of multiple orientations, suggesting extension in various directions. Slight tilting of the Småland mega-block and the faulting along its NW margin is suggested by Milnes et al. (1998) to be probably late Carboniferous or younger in age.
Galena crystals with model ages of 300 – 400 Ma occur in fracture infillings in the Palmottu U-Th mineralisation at Nummi-Pusula in south-western Finland (Vaasjoki 1996). Vaasjoki et al. (2002) report remobilisation and enrichment of U-mineralisation in East-Uusimaa during the Ordovician ca. 450 Ma ago. Kohonen & Rämö (2005) relate these mineralisations to increased permeability and hydrothermal activity along the Neoproterozoic/Palaeozoic unconformity above the present erosional level.
7) Opening of the North Atlantic and uplift of western Scandinavia
There was hardly any deformation within the Fennoscandian Shield during the Mesozoic (Muir Wood 1995). In the Tertiary, the opening of the North Atlantic and the initiation of sea-floor spreading in the Norwegian-Greenland Sea and the beginning of the Alpine continent-continent collision dominated the evolution of north-western 76
Europe. Talvitie (1979) suggests that the seismic activity along the Proterozoic Senja and Lapland fracture zone segments indicates the Mid-Atlantic Ridge push was guided inside the Fennoscandian Shield into NW-trending strike-slip faults. Muir Wood (1995), however, argues that the rheological differences between the Fennoscandian Shield and its surroundings prevented this. The latest phase of deformation mainly affecting the margins of the Fennoscandian Shield was the uplift of western Scandinavia in connection with the opening of the North Atlantic (Jensen et al. 1992, Muir Wood 1995, Riis 1996, Stuevold & Eldholm 1996). The first phase of uplift, amounting close to 1500 m in northern Sweden occurred in the Palaeogene The second major episode of uplift occurred in the Neogene starting from the late Oligocene (Stuevold & Eldholm 1996). Van Balen & Heeremans (1998) explain the morphological difference between the flat Finnish coast and the uneven Swedish coast of the Bothnian Sea as being due to Palaeogene-Neogene differential uplift of Fennoscandia. Based on the uplift analysis of Riis (1996), van Balen & Heeremans (1998) suggest that the uplift of the Bothnian Sea area was about 500 m.
8) Neotectonic movements (postglacial and recent crustal movements)
Postglacial faults with a length of 4-36 km and a scarp height of 0-12 m occur in the Finnish Lapland. In the Swedish Lapland up to 150 km long faults have been found and the maximum scarp height is 35 m. The postglacial faults studied in the Finnish Lapland so far are situated in old, reactivated fracture zones (Kukkonen & Kuivamäki 1985, Paananen 1987, 1989, Vuorela 1990, Kuivamäki et al. 1998). Estimations of earthquake magnitudes connected with postglacial faults in the Finnish Lapland have varied from 5.3 to 7.5 (Kuivamäki et al. 1998). The origin of the postglacial faults can be explained as a result of horizontal tectonic stress induced by the Mid-Atlantic Ridge and quick isostatic land uplift combined with material flow beneath the crust toward the uplift centre. Small post-glacial faults with a scarp height 0–20 cm in ice polished bedrock outcrops have been found in southern Finland, but so far larger post-glacial faults have not been recognised. In the search for post-glacial faults in the vicinity of Olkiluoto in 2006 (Lindberg 2007) no post-glacial faults were positively recognised. A local GPS monitoring network, consisting of 10 concrete pillars, was set up in Olkiluoto in 1994 and enlarged in 2003 with two new pillars to study the local crustal movements. Between 1995 and 2005, the network was measured 20 times. According to the measurements, the bedrock at Olkiluoto is very stable, with only one third of the GPS stations showing statistically significant distance change rates between the stations (Ahola et al. 2006). The local movements between the stations are, however, smaller than 0.22 mm/year. Precise levellings in the GPS network were started in 2003 and the levelling network was connected to the Finnish precise levelling net at Lapijoki, in Eurajoki. To this date, only the two precise levellings has been carried out, but with new levellings in the future it is possible to study the vertical crustal movements at Olkiluoto (Lehmuskoski 2004). 77
3.3.4 Alteration Alteration is not systematically handled or studied in the Finnish geological literature, yet the general retrograde alteration of cordierite is mentioned in the explanations of the geological map-sheet of Rauma (Suominen et al. 1997). Typically the hydrothermal alteration is described in relation to ore geology and prospecting. Hydrothermal alteration and greisen-type mineralisation is well-described from Eurajoki rapakivi stock, some kilometres east of Olkiluoto Island. Several publications deal with the geology, petrology, mineralogy, mineralisation and geochemistry of the granite and the greisen bodies in that area (e.g., Haapala 1974, 1977, 1978, 1986, 1989, 1997, Haapala & Kinnunen, 1979, Haapala & Ojanperä 1969, 1972a, 1972b, Rämö & Haapala 2005, Suominen et al. 1997).
In the Olkiluoto bedrock, the repository and tunnel rock mass volumes show three different alteration episodes, which can be identified and distinguished because of their different products, mode of occurrence and of the consequences of their activity. The three alteration events are independent and remote processes occurring over an immense period of time. The episodes mentioned in chronological order are retrograde phase of metamorphism, episodes of hydrothermal alteration and surface weathering. The latter two processes are the most important ones and are naturally the focus of alteration research simply because they may have practical impacts on bedrock properties.
A retrograde phase of metamorphism has affected the rocks after the main peak of metamorphism at the latest 1790 Ma ago, if not earlier. These retrograde changes can be seen as sericitisation and saussuritisation of feldspars and chloritisation of mafic minerals. Temperature and pressure were relatively high at the moment the retrograde processes occurred compared to those which prevailed during the younger hydrothermal events. The products of the retrograde metamorphism are observable throughout Olkiluoto Island and they represent the rather common regional metamorphic condition in high grade gneisses of the surrounding Satakunta area. The textural evidence of the rock types in the Olkiluoto area, the fractures fillings and the character of the alteration in the rock indicate that the bedrock was subjected after the main stages of regional orogeny to more localized but extensive hydrothermal activity.
Hydrothermal alteration has occurred in several zones due to the circulation of hot corrosive fluid and which changed substantially the mineralogical content of the affected Olkiluoto bedrock substantially. Typical hydrothermal alteration products are Fe-sulphides (pyrrhotite, pyrite), clay minerals (illite, smectite-group, kaolinite) and calcite. However, most of the sulphides, especially pyrrhotite is not solely of hydrothermal origin, but originates from the primary sedimentary protolith of the Olkiluoto gneisses. Drill core observations suggest that pyrrhotite was first remobilized by regional tectonic movements, but later also during the hydrothermal episodes.
The hydrothermal processes are linked to the phases of magmatic activity, which have produced a longstanding (tens to hundreds of millions of years) thermal charge. The driving forces for that system at Olkiluoto are the episodes connected with the rapakivi granite system (1570-1540 Ma). The tectonic regime for that magmatic period was extensional (e.g., Haapala & Rämö 1992, Rämö et al. 2002).
The Laitila rapakivi batholith and the adjacent smaller Eurajoki stock which shows numerous greisen veins, kaolinization of feldspars and associated mineralisation 78
(Haapala 1977), are situated close to Olkiluoto Island. The greisen veins also occur in migmatitic gneisses close to the margin of the Eurajoki rapakivi granites (Figure 3-21). At Olkiluoto, greisen veins have been observed at two locations inside the studied area (Paulamäki 1989, 2007).
In places, greisen veins have irregular shapes, offshoots and inclusions of wall rocks Figure 3-21). They cross-cut the metamorphic structure, banding and layering of the Olkiluoto gneisses and give an impression of a breccia-like structure which actually is a network of veins. Sometimes they form a swarm of narrow subparallel veins. Inside the greisen veins, there are narrow, few millimetres wide fractures filled with quartz and fluorite. Geochemically, the greisens exhibit elevated contents of zinc, tin and copper. For example, 0.49% Zn, 0.08 Sn and 0.03% Cu have been analysed from one greisen vein at Olkiluoto (Paulamäki 1989). At the moment, the greisenisation at Olkiluoto seems to have no significant volumes, but it is indicative of the rapakivi granite relation and the connection with late magmatic fluids. More importantly, the existence of greisen veins is a clear sign of the high heat production nature and capacity of the rapakivi granites (Haapala & Kinnunen 1979).
Figure 3-21. Network of dark greisen veins cross-cutting tonalitic gneiss and amphibolite dyke at Ilavainen in Olkiluoto. Photograph by Kai Front, VTT.
The activity period for fluid flow is understood to be syn- to post-igneous in character; there is strong textural indication that it postdates the rapakivi episode. Blomqvist et al. (1992) reported 1031 Ma, 1353 Ma and 1365 Ma ages for three illite samples in drill core OLKR1. In the ONKALO area, the fault zone OL-BFZ100 (Paulamäki et al. 2006) 79
has yielded ages on illite of 1384 Ma and 1372 Ma (Mänttäri et al. 2007), yet when taking into account the possible K-contamination by detrimental K-feldspar, the age range may be closer to the Postjotnian olivine diabase dykes (1260-1279 Ma). Definitely, the crustal extension maintained the fluid circulation through the opened faults and fractures and promoted the formation of pervasive and fracture-related hydrothermal alteration and generated a longstanding hydrothermal regime in the vicinity of rapakivi intrusion (Front & Paananen 2006, Gehör 2007, in press).
Three main alteration types have been identified at the Olkiluoto site, these are 1) clay mineral formation, which has two main subtypes; illitisation and kaolinisation, 2) sulphidisation and 3) carbonatisation (Figure 3-22). Carbonatisation, or calcite formation in general, is an essential part of the hydrothermal alteration. Alkaline conditions favoured the carbonate forming reactions, and calcitic fracture fillings and the dyke swarm networks are found to be closely connected with practically each one of the hydrothermally influenced zones.
The highly corrosive acidic fluids have increased the effect of hydrothermal alteration. The alteration episodes took place at reasonably low temperature conditions; the estimated temperature interval is from slightly over 300ºC to less than 100qC (Blyth et al. 2000, Gehör et al. 2002) which is based on fluid inclusion studies on fracture calcites. Typically for the hydrothermal regimes, the circulating fluids penetrated the bedrock and generated high permeability zones. These zones appear to have repeatedly acted as pathways for the periodic circulation of thermal fluids. Volumetrically they are clearly more important than greisenisation (see Chapter 4.4).
Figure 3-22. An example of strong pervasive kaolinisation, drillcore OL-KR4, ca. 525 m.
The fracture planes are randomly covered by greenish, clayey calcite. Fluid inclusion determinations have suggested 50-70 ºC trapping temperatures. It has not been ruled out 80
that these “cold” calcite types were precipitated in the Neoproterozoic or Phanerozoic times, maybe even later, during the Devonian. At that time, the stabilised crystalline basement was covered by 0.5 to 1.5-km thick sedimentary strata (Kohonen & Rämö 2005). However, there is no available data on the hydrothermal activity occurring during that time period.
Surface weathering is a process by which rocks are decomposed by the action of external agencies such as wind, rain, temperature changes, plants, bacteria or chemical factors. An essential feature of weathering processes is that they affect rocks in situ. There are two types of weathering: mechanical and chemical. Mechanical weathering can be seen as the expansion of water on freezing, in pores and fractures of the rocks causes the rock to split off. Chemical weathering is mainly brought about by the action of substances dissolved in rain water. They are usually acidic of character and leach rocks actively.
A B
C D
Figure 3-23. A) Strongly weathered pegmatitic granite. OL-TK4,mapping section P30. B) Almost completely weathered mica gneiss. OL-TK4, mapping section P48, C) 1.5 m thick vertical cutting of regolith in OL-TK4, mapping section P76, D) Layers of completely weathered veined gneiss (lower) and granite (upper) overlain by a layer of till on the wall of the OL-TK7 mapping section P30. Photographs by Seppo Paulamäki, Geological Survey of Finland. 81
Climatic factors play a remarkable role in weathering. For example, under tropical conditions, intensive leaching removes most elements from the rock except aluminium and iron which remain as laterite and bauxite. Favourable conditions for deep chemical weathering is considered to have prevailed in Finland during the late Mesozoic, although much older, Mesoproterozoic weathered deposits are also known (Kohonen & Rämö 2005).
Weathering represents the youngest alteration process at Olkiluoto. It is registered in some fragmentary occurrences (Figure 3-23). Presumably, the origin of weathering goes back to at least tens of million of years, although the dating of these formations is difficult. The known weathered sites, however, show strong and quite deep weathering. For example drill hole OL-KR23 shows slightly to strongly weathered core sample to a depth of ca. 56 m.
Interestingly in the area close to the ONKALO access tunnel, kaolinite occurs pervasively in the same zones with sulphides and illite. In this same area, strong weathering is recognized in boreholes, research trenches and opening of the access tunnel. These occurrences may have resulted from interaction between alteration- induced porosity (soft and loose kaolinite pods), fractures in the surface and soluble agents (due to meteoric water and sulphides).
3.3.5 Synopsis
A process-based lithological and structural evolution model of the Olkiluoto site is presented in Table 3-2. The table combines the information gained from the mapping of outcrops, from core logging (rock types, ductile and brittle deformation, migmatite structures and hydrothermal alteration), from more advanced petrological and lithogeochemical studies (protolith and genesis), as well as from studies on metamorphism (mineral paragenesis and metamorphic grade) and mineralogy (fracture minerals and fracture mineral database). Table 3-2. Summary of lithological and structural evolution of the Olkiluoto site.
Time/Age Petrological evolution Structural evolution Structural elements (Ma) <1270 Weathering Exact sequence of events unknown. Reactivation of existing faults and fractures Late Clay Possibly extensional tectonics with vertical crustal movements in period from the Neoproterozoic to Devonian and uplift during the Paleogene to Neogene 1580-1250 Hydrothermal stage Extensional tectonics and compression, Reactivation of existing faults, fractures, Epidote-Calcite-Phengite, Sulphides, Illite exact sequence of events unknown. tension cracks, strike-slip faulting Quartz, Calcite, Kaolinite Brittle deformation, faulting Ca. 1560 Diabase dykes Extension, brittle deformation Reactivation of existing faults, fractures Brittle deformation, thrusting Low-angle thrust faults
<1800 Ductile D5 deformation with steep axial Small flexures or outcrop-scale undulation of 82 planes striking to the SE previous planar elements <1830 Pegmatite (?), K-feldspar porphyry along D4 Zonal D4 deformation in E-W Small, open folds, high-grade shear zones shear zones compression 1860-1830 Pegmatitic New metamorphic event, D3 thrusting (to the N - NW), F3 folding, F3 tight folds, rare S3 axial plane foliation, granite producing abundant potassium D3 shearing high-grade ductile shear zones leucosome granite melts Migmatite structures 1880-1860 Pegmatitic CRD-SILL-BT (T series) D2 thrusting (to the NE), F2 folding, D2 F2 isoclinal to tight folds, penetrative S2 granite GRN-BT (P/S series) shearing foliation, high-grade ductile shearing leucosome OLIV-PHLOG-PYR PYR-AMPH (S series) Migmatite structures
(Leucosome?) D1 S1 foliation, possible F1 folding > 1900 Turbidite sediments Lithological layering S0 Volcanic interlayers (Protolith) Carbonaceous beds 83
4 GEOLOGICAL MODEL
4.1 General principles and overview
The aim of the geological data acquisition programme within the framework of the deep repository project at Olkiluoto is to provide the main platform for the geological Site Model (GSM). A geological model is a simplified representation of bedrock conditions (lithology, deformation zones, fracture network, etc.) within a specified rock volume, in a form, which is amenable to numerical computations whilst still retaining its essential, first-order natural characteristics. Although the essential fundament is geological, the geological model is based on an integration and synthesis of all available data – geological and geophysical, with feedbacks from hydrology, rock mechanics etc. At an early stage of the modelling process (Figure 4-1), data acquisition and processing takes place within each of these disciplines separately, and the data are processed using discipline-specific methods, which are generally accepted within the corresponding scientific communities. At a later stage, however, the different types of data need to be integrated into a common data set for use in the subsequent modelling (Integrated Site Descriptive Model). The geological Site Model provides the geometrical framework and the geoscientific descriptions necessary for development of the rock mechanics models, hydrogeological models and (hydro)geochemical models, which are required for simulating repository behaviour on the short and on the long term, i.e. for the design and construction of the repository and for the demonstration of safety. 84
Figure 4-1. Work phases applied in the construction of the Geological Site Model. The lower part of the diagram is from the UCRP report (Posiva 2003a). In the box above, the work phases are specified more precisely, showing the two main steps in the modelling process and the relation between disciplinary and interdisciplinary work programmes (from Milnes et al. 2007).
Experience worldwide, in all the areas of application in which geological modelling has become an important tool, shows that the process of developing a geological model should take place in two steps, which need to be carried out in sequence and must be separated as clearly as possible. SKB’s strategy document on geological modelling in the site investigation phase (Munier et al. 2003) is structured according to this principle, which is also an implicit tenet of the ONKALO research programme, as indicated above (Figure 4-1). The two steps in the model development can be briefly characterised as follows:
Step 1 – Identification, Characterisation and Parameterisation (ICP)
This is the data-oriented part of the modelling process and its aim is to establish the “fix points” which any model will have to satisfy, and the quantitative data which will serve as the input for the computations. In Munier et al. (2003), the IPC step includes those types of “interpretation” which have become standard methodology in geoscience, what the authors call method-specific interpretation (here called discipline-specific processing, Figure 4-1) and integrative interpretation (here called interdisciplinary processing, Figure 4-1). The goal of Step 1 is, for instance, “to pinpoint and 85
characterise those sections of the borehole which could represent deformation zones, for use as fixed control points within the model volume during subsequent 3D modelling.” (Munier et al. 2003, p. 37). The ICP step is not modelling, sensu stricto, it is the determination of the location, orientation and other quantitative features of the objects being investigated in order to allow modelling to take place. These are the input data, and are subject to errors, which can be estimated or described by distribution functions. Except for the error bars and statistical measures of variability, they are not subject to estimates of confidence or uncertainty. Also, as in normal geological research, alternative hypotheses are continually evaluated (the established methodology of “multiple working hypotheses”, Chamberlin 1890) and the preferred hypothesis is carried forward as the model input, but subject to continuous surveillance.
Step 2 – Extrapolation, Correlation and Visualisation (ECV)
This is the real “modelling” part of the process, also called “subsurface mapping” in other geosciencific contexts (e.g. in the oil industry, see Tearpock & Bischke 1991). In Munier et al. (2003), the ECV step is represented by Chapters 5 and 6, and is based on geometrical, geological and geophysical arguments, and the use of a sophisticated computer visualisation system (in which the “fix points” of the ICP step are embedded). For instance, “3D modelling starts by the creation of modelled structural surfaces ...” “The modelled structural surface is the surface which is created using coordinates from the geological map, specific points on boreholes, or geophysics (i.e. seismics).” (Munier et al. 2003, p. 55). The ECV step uses the locations, orientations and other parameters, with their error bars and distribution functions, as constraints in building the model. Estimates of uncertainty reflect the confidence with which certain extrapolations or correlations from and between the fix points are made, which may also be reflected in alternatives, when criteria for distinguishing between different possibilities are lacking (e.g. two possible correlations of equal confidence). It is in this step that process understanding plays a major role - a “deformation zone”, for instance, is not merely a geometrical element in space, but a geological feature whose mode of formation needs to be understood before different possible geometrical correlations can be evaluated and the degree of confidence established.
At the present stage of investigations at Olkiluoto, the geological model is divided into 5 thematic submodels (Figure 4-2): the ductile deformation model, the lithological model, the alteration model, the brittle deformation model and the statistical model. This subdivision is used as a basis for subdividing the present Chapter into a number of Sections. In addition to geometrical considerations, emphasis in each Section is on the understanding of the mode of formation of the geological features being modelled, as indicated in the preceding paragraph. The subdivision is considered as practical and logical from the deterministic modelling point of view, although it is obvious that it is partly artificial, since the submodels are not independent entities and the corresponding geological processes are closely interrelated - for example, the ductile fabric is an important precursor to the subsequent brittle deformation. This interdependency is presented as arrowed lines in Figure 4-2.
The lithological model provides a general view of the geometry and lithological properties of site-scale rock domains at Olkiluoto that can be defined on the basis of a set of fixed parameters. The goal of the model is to represent the spatial distribution of texturally and structurally fixed and genetically related bedrock units, which, from the 86
perspective of underground construction and long-term safety, are considered to have sufficiently constant properties. The lithological model is presented in Section 4.2.
The ductile deformation model describes and models the products of polyphase ductile deformation, which makes it possible to assess the orientation and effects of the structural and textural anisotropy (including foliation, folding and lineations) and to define the dimensions and geometrical forms of individual lithological units determined in the lithological model. The ductile deformation model is presented in Section 4.3.
The alteration model describes mainly the products of hydrothermal alteration but retrograde metamorphism and subsequent low-temperature weathering, which have also affected the lithological units in the site area, are considered as a part of the long-term alteration history and processes. These processes transform the physical and chemical properties of rock material, and altered rocks may have physical properties, which are notably different from those of primary, fresh rocks. Thus, the degree and type of secondary alteration and retrogressive metamorphism are important parameters in evaluating, for example, the mechanical strength of the rocks. The goal of the alteration model is to present the shapes and volumes of altered bedrock domains as well as different alteration types. The alteration model is presented in Section 4.4.
The brittle deformation model describes the geometry and properties of cohesionless or low-cohesive structures produced at the Olkiluoto site during the periods of brittle deformation, i.e. mainly fault zones, although joint zones may also exist (see section 4.5). Brittle deformation products may have important implications for construction and long-term safety, and an assessment of their properties is presented. In the current geological site model report, focus is on the description of the deterministic features of the brittle deformation; statistical treatment of fractures is presented in Section 4.6, and the results of discrete fracture network modelling will be presented in a separate report. The brittle deformation model is presented in Section 4.5
The fracture system model provides a statistical treatment of fracture properties, both as site-scale phenomenon as for specific volumes of rock, e.g. specific fault zones. It is emphasized that this part of the text is not currently a model, but a statistical analysis of selected fracture data. A proper fracture system model will be presented in the near future. The fracture analysis is presented in Section 4.6. 87
Figure 4-2. Interdependency of different submodels in the context of the development of the present Geological Site Model (for explanation, see text).
4.2 Lithological model
4.2.1 Conceptual model
The characterisation of lithology within rock volumes in blocks 10 x 10 x 10 m3 and greater, and the identification of the boundaries between lithological units at that scale, is the basic background data for constructing a geological model at site scale. It also represents the degree of resolution normally attainable during geological mapping in the field and in tunnels (i.e. description of individual outcrops and tunnel walls, and the construction of geological maps and tunnel profiles), as well as that attainable during on-site geological logging of rock cores (i.e. production of preliminary lithologies). At 88
Olkiluoto, the geological mapping and logging at this scale is complicated by the small- scale heterogeneity of many of the rock units, since it involves visually estimating the bulk lithological uniformity of larger units, and often the mapping of boundaries which represent ill-defined transition zones. Yet, using the experience gathered during the years of site investigation, a general subdivision of the Olkiluoto bedrock into a small number of descriptive lithological types, based on visual field assessment of outcrops, investigation trenches, tunnel walls and cores combined with thin-section analysis of the texture and structure of representative samples, has been established. The applied descriptive types are tailored to the features of the Olkiluoto site and the needs of the present project: for an overview of the general methods of field description of metamorphic and magmatic rocks, see Fry (1984) and Thorpe & Brown (1985), for the general principles of rock classification at Olkiluoto, see Mattila (2006). Applying this classification, lithological units at Olkiluoto can be conceptualised as volumes or domains of rock which have constant properties, from textural and structural point of view and are genetically related. It should be noted that the mineralogy and geochemistry may be similar in units with deviating textural and structural characteristics, pointing to a common protolith origin. For further details, reference is made to Kärki & Paulamäki (2006).
4.2.2 Modelling assumptions and methods
The modelling procedure used to reconstruct the lithological units at depth is described in detail in Paulamäki et al. (2006) and the workflow is shown in Figure 4-3. The basic principle behind the interpretation of the lithologies is that the strike and dip of the composite, pervasive foliation, which is rather constant over large distances, can be used as a guide, through which the lithologies can been correlated between the drillholes and from surface to drillholes (Except for the diabase dikes, see following text). The boundaries of the lithological map of Olkiluoto (Appendix IV) are themselves modelled boundaries since they are reconstructed on the basis of widely spaced natural outcrops, a series of cleared and cleaned trenches through the Quaternary deposits, and an interpretation of geophysical data (Appendix II), as explained in Chapter 2. 89
Figure 4-3. A schematic representation of the workflow in the construction of the lithological model.
In the first step of 3D modelling of the lithological units, mica gneiss, tonalitic- granodioritic-granitic gneiss and pegmatitic granite intersections in drillholes more than ca. 10 metres in thickness have been distinguished as separate units (corresponding to the ICP and data collection and processing/interpretation steps in Figure 4-1). Furthermore, adjacent pegmatitic granite sections less than 10 m in length, separated by short sections of homogeneous or migmatitic gneisses have been combined into larger units, on the assumption that the gneisses represent inclusions or restites within the pegmatitic granite. All the observed and interpreted diabase dykes have been modelled regardless of their width. The simplified lithologies of the drillholes are presented in Appendix V and Figure 4-4.
The veined gneisses form the main volume of the model area and serves as the ‘background’ in the model. The modelled diatexitic gneiss, mica gneiss, tonalitic- granodioritic-granitic gneiss, pegmatitic granite and diabase units are designated DGN+number, MGN+number, TGG+number, PGR+number and DB+number, respectively.
The 3D lithological model has been constructed using Surpac Vision 3D modelling software. The simplified lithological data from drillholes OL-KR1 – OL-KR43 (Figure 4-4) were transferred to the Surpac Vision drillhole database and the data from outcrops and investigation trenches were converted into Surpac string files. Figure 4-5 shows a N-S trending vertical section of the ONKALO area and shows how the pegmatitic granite unit were connected from the surface to the drillholes and from drillhole to another using the orientation of the foliation as a guide. The same also applies the modelling of the MGN and TGG units. 90
Figure 4-4. Tonalitic-granodioritic-granitic gneiss (orange), mica gneiss (dark blue) and pegmatitic granite (red) sections more than 10 m in thickness in drillholes. View from the E.
Figure 4-5. N-S trending vertical section with lithological and foliation data from the drillholes and digitised pegmatitic granite unit (magenta). The pegmatitic granite unit on the surface (upper right corner) is connected to the drillholes using the foliation measurements as a guide. 91
The lithological units were constructed by combining vertical profiles with a spacing of 50 m, occasionally 25 m, together with surface observations. The units were first digitised at one or two central profiles, using the data from several drillholes, when available. These interpretations were then extrapolated to neighbouring profiles, and edited with respect to the available drillhole and surface data, and the resulting modified interpretation was extrapolated to the next profile. This process resulted in several vertical profiles (Figure 4-6 A), which were then connected to a continuous unit (Figure 4-6 B). Figure 4-7 A illustrates a TGG gneiss unit that was observed at the surface and only in one drillhole. The uppermost section in the figure is the interpretation of the rock unit at the surface, based on outcrop observations. The measured dip of the foliation in the outcrop and in the drillhole resulted in the same horizontal segment being extrapolated to the observed TGG gneiss intersection in the drillhole. The segment was further extrapolated to depth at ca. 50 m steps, and was made smaller with depth, in order to make the object geologically reasonable. The assumption regarding the extent to depth of such a rock unit is that it is approximately equal to its greatest lateral extent. Figure 4-7 B shows the rock unit as a completed 3D solid, which extends to a depth of c. 200 m. 92
A
b)
B
Figure 4-6. A) Digitised sections of the modelled pegmatitic granite unit, B) completed 3D solid object. View from up/SSE. The frame indicates the Olkiluoto site volume. 93
OL-KR14 OL-KR10 OL-KR30
OL-KR7
A
OL-KR14 OL-KR10 OL-KR30
OL-KR7
B
Figure 4-7. Construction of a TGG gneiss unit observed at the surface and in one drillhole. A) Interpretation on horizontal planes at about 50 m steps, B) completed solid TGG unit. 94
4.2.3 Spatial model
The 3D lithological model of the Olkiluoto site area currently contains two diatexitic gneiss units, 19 mica gneiss units, 32 units of tonalitic-granodioritic-granitic gneisses, 62 units of pegmatitic granite, and seven diabase dykes. Figure 4-8 shows a N-S vertical section through the central part of the site area, presenting the modelled lithologies therein. The surface locations of the modelled lithological units, which are outcropping, are presented in Figure 4-9, together with their identification numbers.
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase
Figure 4-8. Vertical section in N-S direction along the coordinate line y = 1525600. View from the E. 95
TGG27
TGG26 DB2 TGG15 DB3 DB1 PGR25 PGR59
DB7 PGR64 TGG7 PGR26 TGG13 PGR2 DB6 TGG20
PGR5 PGR19 PGR1 DB5 PGR34 PGR19 TGG3 PGR17
PGR16 PGR15 PGR6 TGG30 PGR20 TGG19 PGR36 PGR12 TGG18 PGR14
TGG1 TGG9
DGN1 TGG4 TGG28
TGG11 TGG8
DGN2 TGG10
Figure 4-9. Surface location of the outcropping lithological units, which have been modelled in 3D, together with their identification numbers.
Diatexitic gneiss/veined gneiss contact zone
The NW transitional contact between diatexitic gneiss unit DGN1 and the veined gneiss has been constructed on the basis of the distribution of the lithologies in the ONKALO access tunnel and in drillholes OL-KR4, OL-KR8, OL-KR22, OL-KR23, OL-KR24, OL-KR25, OL-KR26, OL-KR27, OL-KR28, OL-KR31, OL-KR34, OL- KR35, OL-KR36, OL-KR37, OL-KR38 and OL-KR40 and the tectonic observations therein. The observations in ONKALO and in the drillholes connected to surface map results in a fold-like contact, which rather gently dips to the SSE (Figure 4-10). This is in good agreement with the foliation measurements in outcrops, trenches and drillholes within the central part of the site, including the ONKALO area. The foliation measurements in outcrops suggest that the dip of the foliation becomes much steeper to the S and SE of the ONKALO area. The SSE contact of DGN1 and both contacts of diatexitic gneiss unit DGN2 have been modelled accordingly (Figure 4-10).
On the basis of analysis of structural data from the outcrops, investigation trenches and the drillholes, the contact zone is suggested to be due to thrust related deformation during deformation phase D3, causing the diatexitic gneisses to have been thrusted from the southeast upon the veined gneisses. 96
DGN1
Figure 4-10. Diatexitic gneiss units DGN1 and DGN2. View towards the ESE. For the lithology of the drillholes, see Figure 4-4. The site area is marked with a box. For the lithology of the drillholes, see Figure 4-4.
Mica gneiss units
The mica gneisses were not modelled in the previous geological models (Paananen et al. 2006, Paulamäki et al. 2006) but they were incorporated into veined gneisses. From the experience from the ONKALO access tunnel and from the areas with large number of drillholes close to each other, the mica gneisses are probably just inclusions with limited dimensions and they have been modelled accordingly. Most of the mica gneiss inclusions in the ONKALO access tunnel are so small that they have not been modelled. However, some of them could have been connected to wider mica gneiss units modelled from the drillholes. The mica gneisses are rather homogeneous, containing not over 10% of narrow granitic leucosome veins. Some of the modelled mica gneiss units, however, may contain more granitic material, because they also include wider (1-3 m) crosscutting or foliation-parallel pegmatitic granite dykes. The interpreted mica gneiss units are listed in Table 4-1 and shown in 3D in Figure 4-11. The distribution of the orientations of the modelled units is shown in Figure 4-12. 97
Table 4-1. Modelled mica gneiss units of the Olkiluoto site area. The orientations of the modelled units are based on an average value of the foliation measurements within the drillhole intersections.
Mica gneiss unit Intersection in the Orientation (dip Proportion of Remarks drillhole direction/dip) granitic leucosome (%) MGN1 KR22 424.5- 132/35 7.5 Calculated 483.96 intersection in the KR25 424.9- ONKALO access 430.95 tunnel in chainage 4085-4165 m. MGN2 KR4 332.95-371.3 128/35 40 Calculated KR24 376.6-391.3 intersection in the KR38 359.0- ONKALO access 373.95 tunnel in chainage 4350-4385 m. MGN3 KR29 455.05- 144/32 25 514.7 MGN4 KR8 484.2-524.1 142/22 20 MGN5 KR3 40.56-76.65 146/30 5 MGN6 KR3 88.7-138.3 174/38 16 Includes a total of 7.5 m of PGR dykes. MGN7 KR7 300.4-322.25 153/50 10 Calculated intersection in the ONKALO access tunnel in chainage 3395-3415 m. MGN8 KR25 520.3-544.3 181/42 5 MGN9 KR4 455.0-464.5 130/48 40 MGN10 KR38 231.7-241.4 103/50 40 MGN11 KR10 149.8- 100/46 No data Intersection in the 161.85 ONKALO access tunnel in chainage 1355 – 1360 m. MGN12 KR10 466.3-482.5 180/43 No data MGN13 KR7 117.9-136.0 152/53 10 Intersection in the PH5 182.85-194.8 ONKALO access tunnel in chainage 1171.9 – 1183.6 m. MGN14 KR29 689.1-708.3 175/55 25 MGN15 No intersections No data Former TGG14. MGN16 KR19 233.0-259.0 176/33 5 MGN17 KR5 363.9-385.9 170/35 4 MGN18 KR11 921.0-949.3 183/59 No data MGN19 KR15 423.75- 165/32 9.5 Includes a total of 463.3 2.75 m of PGR dykes. 98
MGN16 MGN13
MGN5
MGN6
MGN17 MGN19
MGN4
MGN18
MGN3
MGN14
Figure 4-11. Modelled mica gneiss units MGN1-MGN18 within the Olkiluoto site. A view towards the NNE. For the lithology of the drillholes, see Figure 4-4. Some of the larger mica-gneiss units are labelled with their MGN-number (see Table 4-1), wherever the labelling did not obscure the 3D view. The site area is marked with a box. For the lithology of the drillholes, see Figure 4-4. 99
Figure 4-12. Distribution of the orientations of the modelled mica gneiss units. Equal area, lower hemisphere projection.
Tonalitic-granodioritic-granitic gneiss units
The modelled tonalitic-granodioritic-granitic gneiss (TTG) units are listed in Table 4-2 and shown in 3D in Figure 4-13. The distribution of the orientations of the modelled units is shown in Figure 4-14. TGG units 1-17 were included in the GSM version 0 (Paulamäki et al. 2006), whereas TGG units 18-34 are new in the present GSM version. The TGG gneisses themselves are homogeneous, containing only a few leucosome veins. The modelled TGG units may show some heterogeneity in the form of crosscutting pegmatitic granite dykes, ranging in width from a few tens of centimetres up to several metres. Their proportion is, however, less than ca. 25% of the total volume of the unit. 100
Table 4-2. Modelled TGG units of the Olkiluoto site area. Modelled TGG units of the Olkiluoto site area. The orientations of the modelled units are based on an average value of the foliation measurements within the drillhole intersections and/or in the outcrops.
TGG-unit Intersection in the Orientation Proportion of Remarks drillhole (dip granitic direction/dip) leucosome (%) TGG1 KR8 15.45-30.8 No data Intersection in the ONKALO KR26 4.8-7.6 access tunnel in chainage 0- KR28 0.3-34.2 9.5 m. Exposed on the PH1 16.24-32.89 surface. TGG2 KR8 210.2-266.15 153/40 12 Former TGG2 extended to KR37 138.6-179.5 drillhole OL-KR37. Intersection in OL-KR8 include 8.6 m of PGR dykes. TGG3 Outcropping, no 130/64 1 No changes made compared drillhole intersections to the previous model. TGG4 Outcropping, no 173/46 5 Surface expression slightly drillhole intersections changed. TGG5 KR30 4.2-27.65 154/56 2 No changes made compared to the previous model. Exposed on the surface. TGG6 No intersection in OL-KR29. Re-interpreted as a migmatitic gneiss and removed from the model. TGG7 KR2 297.1-398.5 177/52 12 No changes made compared KR12 406.65-495.4 to the previous model. KR13 275.2-410.0 Exposed on the surface. KR14 373.3-441.4 Intersection in OL-KR14 KR15 360.0-396.0 include a total of 25.75 m of rocks other than TGG (mainly PGR and VGN). TGG8 Outcropping, no 5 Surface expression slightly drillhole intersections changed. TGG9 Outcropping, no 168/53 5 Surface expression changed. drillhole intersections TGG10 Outcropping, no 185/75 7.5 Surface expression changed. drillhole intersections TGG11 Outcropping, no 176/56 2 Surface expression changed drillhole intersections by joining of TGG11 and TGG12. TGG12 Outcropping, no Incorporated into TGG11. drillhole intersections TGG13 KR21 82.4-111.2 184/42 5 No changes made compared to the previous model. Exposed on the surface. TGG14 Outcropping no No TGG intersections in OL- 101
drillhole intersections KR29. Re-interpreted as mica gneiss. Removed from the model as a TGG unit. TGG15 KR5 171.5-240.05 180/35 10 New intersection in OL- KR20 251.4-359.2 KR43. Exposed on the KR33 143.05-266.5 surface. Intersection in KR20 KR43 42.6-87.6 include 14.7 m of PGR dykes, and intertsection in KR33 24.2 m on VGN. TGG16 KR5 342.05-385.9 3.5 Intersection in OL-KR5 re- interpreted as TGG and MGN. No intersection in OL- KR43. Consequently, the length of the unit must be shorter and the dip steeper than modelled earlier. Exposed on the surface. TGG17 KR2 889.95-909.95 173/50 10 Connections to OL-KR1 at KR2 937.3-956.6 935-946 m and OL-KR2 at KR11 977.5-1002.11 827-843 m removed. TGG18 KR40 153.6-169.8 164/42 15 New TGG unit. TGG19 KR9 50.0-68.8 142/43 5 New TGG unit. KR27 136.7-150.6
TGG20 KR1 790.0-808.4 155/47 5 New TGG unit. KR2 758.75-768.5 TGG21 KR11 441.2-461.02 166/45 No data New TGG unit. KR41 238.3-271.6 TGG22 KR1 935.3-946.0 161/44 0 New TGG unit. Formerly part of TGG17. TGG23 KR1 427.85-441.9 181/23 5 New TGG unit. TGG24 KR2 174.8-196.8 176/50 10 New TGG unit. KR12 268.3-281.35 KR32 142.15-151.8 TGG25 KR12 371.55-383.15 140-160/25 No data New TGG unit. KR42 385.00-392.85 TGG26 TK8/P127-P138 180/48 10-25 New TGG unit. (56.34 m), no drillhole intersections TGG27 TK8/P148-P153 176/58 <5 New TGG unit. (40.48 m), no drillhole intersections TGG28 Outcropping, no 176/45 No data New TGG unit. drillhole intersections TGG29 Outcropping, no 189/45 No data New TGG unit. drillhole intersections TGG30 Outcropping, no 115/40 No data New TGG unit. drillhole intersections 102
TGG31 KR11 358.1-368.3 160/32 No data New TGG unit. TGG32 KR1 326.5-336.6 180/50 5 New TGG unit. TGG33 KR43 914.3-927.55 190/45 No data TGG34 KR5 342.1-363.9 170/30 3 New TGG unit. Replaces TGG16 in OL-KR5. TGG35 KR15 96.4-108.9 131/52 15 New TGG unit. KR18 79.0-85.0
TGG29 TGG28 TGG3 TGG19 TGG18 TGG9 TGG27 TGG26 TGG7 TGG10 TGG13
TGG7 TGG11 TGG15 TGG32 TGG8
TGG23
TGG16
TGG22 TGG20
TGG33 TGG17
Figure 4-13. Modelled TGG units within the Olkiluoto site. A view from the SW. For the lithology of the drillholes, see Figure 4-4. 103
Figure 4-14. Distribution of the orientations of the modelled tonalitic-granodioritic- granitic gneiss units. Equal area, lower hemisphere projection. 104
Pegmatitic granite units
The modelled pegmatitic granite units of the previous geological model of the Olkiluoto site (Paulamäki et al. 2006) are listed in Table 4-3, together with changes made during the current modelling effort. New pegmatitic granite units, mainly based on data from new drillholes OL-KR34 – OL-KR43, are presented in Table 4-4. All the modelled units are shown in 3D in Figure 4-15. The distribution of the orientations of the modelled units is shown in Figure 4-16. The outcrops and the investigation trenches have demonstrated that the pegmatitic granites may be very homogeneous in some cases but usually they are heterogeneous containing numerous inclusions and restites of different gneisses and migmatites of the site. This heterogeneity is shown in column 4 in Tables 4-3 and 4-4 as a proportion of pure pegmatitic granite in the drillhole section. The modelled pegmatitic granite units may be even more heterogeneous, since the units are partly assembled so that several nearby drillhole sections, a few metres in length, separated by short sections of gneisses and migmatites, have been combined into larger units. This heterogeneity is shown in column 5 in Table 4-3 and Table 4-4. For example, pegmatitic granite units PGR 2, PGR8 and PGR19 are in places very heterogeneous, the drillhole sections containing several narrow sections of migmatitic and other gneisses. In case of PGR 19, this is in good agreement with the observations of the same unit in outcrops and investigation trenches (see Paulamäki 1996).
Table 4-3. Modelled pegmatitic granite units of the Olkiluoto site area (Paulamäki et al. 2006) with changes made on the basis of new drillholes. The orientations of the modelled units are based on an average value of the foliation measurements within and in the hanging-wall and footwall contacts of the PGR drillhole intersections.
Pegmatitic Orientation Intersection in the Amount of Proportion Changes made granite (dip drillhole/trench leucosome of other rock compared to the unit direction/ (%) sections geological site model dip) within the v0 PGR unit (%) PGR1 180/35 KR9 352.8-370.1 n.d. 0 No changes made. Preliminary intersection in OL- KR46 at 81.3-149.1 m. PGR2 183/35 KR2 139.85-174.8 85 18 Extended to drillhole KR4 464.5-483.2 92.5 5 OL-KR38. KR10 336.85-364.95 n.d. 31 Calculated KR12 208.1-225.3 n.d. 0 intersection in the KR13 68.05-150.6 94.5 10 ONKALO access KR14 282.7-311.1 92.5 24 tunnel in chainage KR15 293.25-306.4 90 0 3765-4045 m. KR24 539.3-548.05 98 0 KR25 437.95-462.45 95 0 KR28 520.8-559.87 99 4 KR33 125.6-130.2 100 0 KR38 491.0-527.5 97.5 24 TK8 P22-P24 (26.8 100 32 m) 105
PGR5 180/30 KR1 169.0-199.4 98 7 Extended to drillhole KR5 0.0-9.0 n.d. 0 OL-KR39. KR20 63.6-87.6 96 30 KR20 144.15-162.9 95 0 KR21 2.95-19.3 92 22 KR21 57.2-82.4 97.5 6 KR33 13.35-46.4 80 0 KR39 237.9-251.0 98 0 PGR6 155/52 KR7 213.8-225.4 80 20 No changes made. PGR8 173/38 KR1 441.9-488.95 93 32 Extended to KR3 452.8-462.6 97 0 drillholes OL-KR3, KR4 769.65-807.0 91 23 OL-KR7, OL-KR20 KR7 653.0-723.3 96 28.5 and OL-KR39. KR14 485.7-508.8 96.5 15 KR15 479.0-505.0 98.5 24 KR39 473.1-496.9 97 0 PGR9 180/38 KR2 421.3-455.9 95 3 Extended southwards KR4 815.8-866.4 95 0 to drillhole OL- KR12 509.7-567.1 n.d. 35 KR40. Extension to KR40 988.35-1017.3 88 0 the north reduced because no PGR intersection occurs in new drillhole OL- KR41 at a proper depth. PGR11 160/16 KR8 524.4-535.45 90 18.5 Extended to drillhole KR9 304.1-328.4 n.d. 0 OL-KR40. KR27 421.1-426.7 97 0 Connection of former KR40 406.6-459.7 88 0 PGR11 to OL-KR8 at 565.4-600.69 m cut off. Intersection in OL-KR27 reduced due to re-logging of the drillhole. PGR12 161/50 Outcropping, no n.d. 0 No changes made. intersections PGR13 164/40 Outcropping, no n.d. 0 No changes made. intersections PGR14 155/62 KR7 9.8-14.8 80 0 No changes made. PGR15 147/34 KR10 0.0-17.63 n.d. n.d. No changes made. TK4 P39-P41 (25.3 29 m) PGR16 155/55 KR10 128.7-136.1 n.d. 0 Extended to ONK- PH6 14.12-16.62 n.d. 0 PH6 corresponding TK4 P31-P33 (22.1 100 28 ONKALO chainage m) 1418-1421 m PGR17 147/45 No intersections n.d. 0 No changes made. PGR18 137/79 KR14 14.15-22.2 85 0 No changes made. TK4 P30 (12.15 m) 0 PGR19 165/47 KR1 0.0-38.4 n.d. 0 Extended to KR3 0.0-43.7 n.d. 0 drillholes OL-KR39 KR7 258.6-285.95 80 0 and OL-KR42. KR10 202.6-246.6 n.d. 10 Calculated KR12 0.0-57.0 n.d. 0 intersection in the KR14 95.35-153.65 92 5 ONKALO access KR15 39.9-88.78 95 36 tunnel in chainage KR16 58.75-117.75 98 28 2230-2330 m. 106
KR17 30.0-45.3 98 0 KR17 56.55-80.2 96 48 KR18 58.4-79.0 97.5 11 KR18 100.4-123.85 91 20 KR39 106.45-144.4 99 7 KR42 57.35-71.7 n.d. 0 TK4 P24-P29 (10.1 100 27 m) PGR20 151/41 KR25 130.85-140.9 80 0 Extended to ONK- PH5 35.6-46.2 n.d. 0 PH5. Intersection in TK4 P51 (1.7 m) 100 0 the ONKALO access tunnel in chainage 442-451 /430-437m and in 1024.1-1034.7. PGR21 160/29 KR4 589.65-606.65 98 0 No changes made. KR10 537.8-544.55 n.d. 0 PGR22 173/45 KR11 825.1-848.72 n.d. 0 Removed from the model and the intersection connected to PGR27. PGR23 155/37 KR9 551.8-560.85 n.d. 0 Due to connection to KR40 928.15-937.2 100 0 OL-KR40, the dip is steeper than in the previous model. The down-dip extent has been diminished. The orientation has been changed from 180/30° to 155/37° for better fit to the foliation measurements. PGR25 175/43 KR11 305.37-330.35 n.d. 0 Connected to OL- KR41 160.8-191.5 n.d. 37 KR41. PGR26 178/40 KR11 180.2-192.05 n.d. 0 Connected to OL- KR41 46.5-84.0 n.d. 0 KR41. PGR27 174/40 KR1 920.15-935.3 98 0 Connected to OL- KR1 946.0-970.05 95 0 KR11 at 825.1-848.7 KR2 742.9-758.75 95 0 m and 853.9-881.75 KR2 768.5-815.1 95 6 m, where PGR22 and KR2 821.15-843.15 90 0 PGR32, respectively, KR11 825.1-848.7 n.d. 0 of the previous model KR11 853.9-881.75 n.d. 45 merged to PGR27. PGR28 170/57 KR2 858.45-878.5 Removed from KR11 899.1-921.0 drillhole OL-KR2. Modelled with the same number in drillhole OL-KR11. PGR29 174/45 KR2 909.95-936.45 97 0 Extended to drillhole KR11 949.3-977.5 n.d. 0 OL-KR11, where PGR33 of the previous model merged to PGR29. PGR30 180/40 KR1 336.6-348.1 95 0 No changes made. KR20 181.7-199.05 95 0 PGR31 180/34 KR2 238.3-245.9 95 0 No intersection in KR14 354.5-368.3 95 0 OL-KR15. 107
PGR32 178/45 KR11 860.05-881.75 Removed from the model and the intersection connected to PGR27. PGR33 174/44 KR11 949.3-977.5 Removed from the model and the intersection connected to PGR29. PGR34 148/47 Outcropping, no n.d. 0 No changes made. intersections PGR35 Outcropping, no Removed from the intersections model, because no pegmatitic granite occurs in OL-KR34, OL-KR35 and in the ONKALO access tunnel. PGR36 143/52 Outcropping, no n.d. 0 No changes made. intersections
Table 4-4. Pegmatitic granite units modelled after completion of the previous geological model by Paulamäki et al. (2006). The orientations of the modelled units are based on an average value of the foliation measurements within and in the hanging-wall and footwall contacts of the PGR drillhole intersections.
Pegmatitic Orientation Intersection in the Amount Proportion Remarks granite (dip drillhole of of other unit direction/ leucosom rocks dip) e (%) within the PGR unit (%) PGR37 120/30 KR8 194.85-210.2 82.5 8.5 Intersection in the KR37 105.9-138.6 86.5 0 ONKALO access PH4 12.02-26.62 0 tunnel in chainage 886.1-900.7 m PGR38 075/45 KR8 55.55-67.4 75 0 PGR39 150/40 KR40 751.75-791.6 100 0 PGR40 152/45 KR3 156.85-180.4 80 0 KR39 430.1-438.95 85 0 PGR41 115/30 KR27 362.0-389.95 96.5 16 PGR42 162/36 KR6 67.55-103.25 75 15.5 PGR43 143/52 KR38 163.75-203.95 98.5 11 Possible intersection in OL-KR24 at 257.0-260.5 m. PGR44 158/39 KR22 379.0-381.3 100 0 KR25 319.6-332.8 70 0 PGR45 161/42 KR24 399.05-413.6 87.5 10 Calculated KR38 383.85-403.1 98 0 intersection in the ONKALO access tunnel in chainage 4400-4410 m. PGR46 098/50 KR8 121.6-147.75 84 0 108
KR23 200.65-203.75 85 0 PGR47 178/50 KR9 183.2-199.4 n.d. 0 PGR48 136/33 KR25 247.25-258.0 80 0 KR28 290.6-296.0 98 0 PGR49 165/46 KR4 422.75-433.0 80 0 KR28 481.95-488.1 95 0 PGR50 124/45 KR2 1000.8-1012.9 90 0 PGR51 161/30 KR6 263.0-275.3 90 0 PGR52 130/33 KR6 334.4-347.5 84 0 PGR53 168/30 KR2 962.25-968.4 90 0 Outcrops probably KR6 591.6-600.8 60 0 offshore in the KR43 492.6-544.4 n.d. 7 bottom of Eurajoensalmi, north of Olkiluoto (see Suominen et al. 1993). PGR54 167/33 KR43 768.15-797.25 n.d. 0 Outcrops probably offshore in the bottom of Eurajoensalmi, north of Olkiluoto (see Suominen et al. 1993). PGR55 178/44 KR2 478.1-485.5 90 0 KR12 634.3-644.5 n.d. 0 KR13 489.85-500.2 95 0 PGR56 181/24 KR5 104.3-106.1 98 0 KR21 183.1-197.0 92.5 0 KR33 104.5-116.95 100 0 PGR57 162/31 KR5 283.7-294.5 100 10 KR19 287.65-295.6 98 0 PGR58 174/54 KR15 395.35-423.75 92.5 22 PGR59 182/33 TK8/P55-P59 (27.78 98 0 m) KR19 79.95-87.4 100 0 PGR60 145/50 KR23 185.1-203.75 77.5 30 PGR61 160/45 KR40 617.4-630.5 99 0 PGR62 190/45 KR43 927.55-940.25 n.d. 0 PGR63 190/40 KR43 603.85-615.65 n.d. 0 PGR64 176/37 TK8/P44-P47 (24.4 100 15 m) KR19B 5.5-14.1 n.d. 0 PGR65 145/20 KR8 565.4-600.69 95 0 Connection of former KR27 473.15-485 70 0 PGR11 to drillhole OL-KR11 at 304.1- 328.4 m cut off. 109
Figure 4-15. Modelled pegmatitic granite units within the Olkiluoto site. A view towards the ENE. Some of the larger pegmatitic granite units are labelled with their PGR-number (see Tables 4-3 and 4-4), wherever the labelling did not obscure the 3D view. The site area is marked with a box.. For the lithology of the drillholes, see Figure 4-4.
Figure 4-16. Distribution of the orientations of the modelled pegmatitic granite units. Equal area, lower hemisphere projection. 110
Diabase dykes
The diabase dykes are younger than the other rock types at Olkiluoto and they cross-cut the foliation, which determines the orientation of the other modelled rock units. The orientation of four of the modelled diabase dykes is based on direct observations in outcrops or in the investigation trenches. One dyke has been modelled solely on basis of geophysical interpretation, and orientation of two dykes intersected by drillholes has been determined on the basis of geophysical interpretation. The modelled diabases are listed in Table 4-5 and shown in 3D in Figure 4-17. The distribution of the orientations of the modelled units is shown in Figure 4-18.
Diabase dykes DB1-DB6 were included in the previous Geological model of the Olkiluoto site (Paulamäki et al. 2006), whereas dyke DB7 is a new one. The modelled diabase dykes are probably not so continuous as shown in Figure 4-17 , but may appear en echelon, i.e., they are formed by parallel dykes, which are offset in either a left- stepping or right-stepping manner, as shown in Figure 4-19.
Table 4-5. Modelled diabase dykes of the Olkiluoto site area (Paulamäki et al. 2006).
Diabase dyke Intersection in the Orientation Remarks drillhole or in the trench DB1 OL-TK8 mapping 352/82 Width 2.5 m. section P72-P73 DB2 OL-TK8 mapping 343/70 Width 2.5 m. section P138-P139 DB3 KR6 393.7-395.8 001/67 Low-altitude KR6 398.6-399.5 aeromagnetic anomaly DB4 No intersections 005/80 Low-altitude aeromagnetic anomaly DB5 OL-23 337/70 Low-altitude aeromagnetic anomaly DB6 OL-TK3 mapping 313/55 Width 0.5 m. section P41 DB7 Outcrop 330/84 Width ca. 1 m 111
Figure 4-17. Modelled diabase dykes within the Olkiluoto site. A view towards the NE. For the lithology of the drillholes, see Figure 4-4. Diabase dykes are labelled with their DB-number (see Table 4-5). The site area is marked with a box.
Figure 4-18. Distribution of the orientations of the modelled diabase units. Equal area, lower hemisphere projection. 112
Figure 4-19. Narrow right-stepping diabase dyke in Ilavainen at Olkiluoto. Photo Kai Front , VTT.
4.2.4 Evaluation of uncertainties
The main uncertainties of the lithological model are presented in Table 4-6. All uncertainties are categorised under two general headings, “conceptual”, referring to uncertainties associated with the conceptual thinking applied in the modelling, and “technical”, referring to the technical uncertainties of the modelling, caused by modelling methodologies and available data. The magnitude of the uncertainty reflects empirical estimation of the importance of the uncertainty on the confidence of the model, and this is naturally related directly to the predictive capability of the model. Low magnitude means that the uncertainty has only a minimal effect on the confidence of the model, whereas high magnitude implies that due to a specific uncertainty, the confidence of the model is lowered and has direct consequences on the predictive capability of the model. Medium magnitude refers that the specific uncertainty has an impact on the confidence, and should be taken into account, although the impact is not considered as major. Table 4-6. Assessment of uncertainties related to the lithological model.
UNCERTAINTY CAUSE MAGNITUDE EFFECT HOW CAN BE RESOLVED?
Conceptual
Difficulty in the determination Poor exposure of the Low in the modelled site area Inaccuracy of the 2D model, Application of re-processed of the location of lithological bedrock, the visible due to good coverage of direct input to the sizes of 3D and new surface geophysical boundaries outcrops representing only investigation trenches and units. data, excavation of about 4% of the total drillholes, medium in the investigation trenches in bedrock area. Gradational areas outside areas of poor exposure. nature or internal heterogeneity (e.g. shorter sections of migmatitic gneisses within pegmatites) of the rock types. 113
Geometry and extent of Application of ductile Medium in the modelled area, Inaccuracy of the 3D model. Application of data from new lithological units at depth deformation model and high in the areas outside There are likely to be local drillholes and usage of P/O- especially the orientation of deviations from the modelled studies. Assessing the effect foliation in the cross-hole orientation of the lithological of local or small-scale folding correlation. Uncertainties in units due to local-or small and the uncertainties of the the ductile deformation model scale heterogeneities within ductile deformation model are directly reflected in to the the orientation of the foliation. lithological model
Determination of lithological Subjective view of various Medium, concerns especially The “fixed points” acting as Concurrent calibration of the units from drillholes, tunnel mapping geologist, different migmatite variants the input for the lithological views of various geologists to and outcrops gradational nature of the rock 3D model contain improve QA-aspects of the types inaccuracies, directly mapping. Crosschecking of effecting the 3D model the data by modellers. Technical
Geometry and extent of Low density of drillholes and Medium in the modelled area, Inaccuracy of the 3D model Drilling of new drillholes to lithological units at depth large distances between high in the areas outside, yet areas of low resolution, drillholes the confidence is increased application of geophysics by the application of the knowledge on the effect of anisotropy.
Existence of unknown Data resolution (i.e. so-called In the modelled area there is Local features may be Through prediction-outcome lithological units white areas), orientation bias a low uncertainty that intersected in unexpected studies, i.e. how many due to quite uniform drilling unknown site-scale places. unknown lithological were orientation lithological would exist, but for met compared to the smaller units the uncertainty predicted? What were the is considered as medium. properties of these units? 114 115
4.3 Ductile deformation model
4.3.1 Conceptual model
The aim of conceptual modeling work is to produce a regional structural interpretation of the present bedrock surface section and extend it to cover a bedrock volume down to the depth of 1 km.
Structural evolution of the Olkiluoto site is discussed in the Section 3.3. According to the observations, the primary sedimentary structures and earliest structural elements of D1 deformation are rarely identifiable but mostly totally destroyed by later deformations. Thus the interpretation does not involve regional estimation of the products of the early stage deformation. The second stage in the structural sequence, D2 deformation, is assumed to be the most significant and intense event in the structural evolution and the bedrock is pervasively affected by it. Thrust-related deformation and metamorphism in high-grade amphibolite facies conditions led to generation of a migmatite complex in which primary features of epi- and pyroclastic supracrustal formations are poorly observable. Thus the earliest elements sketched in the regional interpretation are border zones between various migmatite units and average strikes of foliations and leucosomes within certain migmatite units which are products of second stage of regional deformation.
The intensities of subsequent phases of deformation vary regionally and remarkable impact of individual events is focused on particular subzones. An ENE – WSW striking zone, intersecting the central part of the study site is most intensely affected by D3 deformation. Pervasive foliations and migmatite structures striking in the NE – SW direction as well as wide pegmatites and axial surfaces of overturned F3 folds are often detected inside that zone. Several narrow subzones elsewhere in the Olkiluoto show features of the same deformation but the most important domain affected by thrust related D3 deformation with overturned F3 folds intersects the central part of Olkiluoto. Thus, the structural interpretation of the surface section depicts only elements located in this zone. In the northern part of the study site, an E-W striking ductile shear zone, Selkänummi Shear Zone (SNSZ) and in the south a parallel Liikla Shear Zone (LSZ) deform the bedrock. The development of these oblique-slip shear zones, which in horizontal section show mostly dextral kinematics, is thought to be associated with D3 deformation. These zones are rather wide and dominated by various shear related structural elements such as southward dipping blastomylonitic foliations. As a whole, both of these zones seem to be remarkable structural components and in the result of regional interpretation both these zones are depicted (Figure 4-20, see also Appendix XII).
The next deformation stage D4 affected most strongly the bedrock within a 0.5 km wide zone which intersects the central part of the Olkiluoto site, extending to the north and south. Within that zone, the F4 axial surfaces, ductile D4 shear zones and foliations in general are NNE-SSW striking (Figure 4-20). In the surface section mean orientation of o S4 foliation is ca. 110/40 but in the deeper parts it bends to more gentle orientation. In the simplified structural interpretation only this zone is presented as a result of D4 deformation. 116
SNSZ
LSZ
F3 axial suface D3 shear zone D4 shear zone/F4 axial surface
Figure 4-20. Structural interpretation of Olkiluoto Site area. The map indicates the most intensely deformed subdomains affected by deformation stages D3 and D4. SNSZ = Selkänummi shear zone, LSZ = Liikla shear zone.
4.3.2 Modelling assumptions and methods
The modelling procedure of the ductile deformation is shown thematically in Figure 4-21. The three-dimensional ductile deformation model attempts to visualize the directions of foliations planes of structural symmetry and locations of most intensely deformed subzones in the Olkiluoto site (Figure 4-20). The main ductile structure in the intact rock at Olkiluoto is the composite foliation, S0-1-2, which was formed during the 117
period of migmatite formation. After the reconstruction of the structural interpretation based on surface and subsurface mapping, the orientation of the pervasive foliation, determined from the surface and the drillholes (For an example, see Figure 4-22 ), was applied in the extrapolation of the 2D structural reconstruction into 3D (ECV step, Figure 4-23).
For the lithology, reference rock volumes of 1 m3 and ca. 30 m3, roughly represented by a core length of 1 m and an area of tunnel wall of 10 m2, were used to indicate the scale of characterisation. For the purposes of orientation analysis, these scales will also be used as reference scales. It will be assumed that a single measurement of the orientation of the foliation within a 1m3 rock volume (or along a 1m length of core or scanline) is representative of the planar anisotropy, which characterises that volume. Similarly, in areal mapping, it will be assumed that the maximum number of orientation measurements which are to be averaged to derive the mean orientation within a 10 m2 window is 10, although, this number can be considerably reduced using visual judgement. In general, however, it is assumed that a single orientation measurement of foliation is representative of 1m3 of rock, and that, for larger volumes, a mean value derived from several measurements must be established.
Figure 4-21. A schematic representation of the workflow in the construction of the ductile 3D model. 118
Figure 4-22. An example of measured foliation orientation from drillholes. Single measurements are represented as blue ticks, showing the apparent dip and dip direction of the foliation, whereas domains of different types and degrees of foliations of constant orientations are presented with varying thicknesses and colours.
Figure 4-23. An example of the cross-hole correlation of the 2D structural interpretation, based on the orientation of foliation measured from drillholes. Single measurements are represented as blue ticks, showing the apparent dip and dip direction of the foliation, whereas domains of different types and degrees of foliations of constant orientations are presented with varying thicknesses and colours. Brown surfaces represents the 3D interpretation of the ductile deformation. 119
4.3.3 Spatial model
The main focus of the ductile deformation model is on the identification of structural domains which can be considered "statistically homogeneous" with respect to a particular parameter or parameters (in this case orientation of foliation, axial plane and interpreted deformation intensity of certain deformation stage), whereby "homogeneous" here means that the whole domain can be represented meaningfully by a single parameter or a combination of parameters (width, length, dip and dip direction). The interpreted structural domains related to the orientations of the axial surfaces and rarely developed axial surface foliations of the late stages D3 and D4 are shown in Figure 4-24 although the most comprehensive demonstration of the results of the structural interpretation is included in the lithological 3D model. The 3D model visualises the domains affected most intensively by these late stage deformations and the anticipated orientations of S3 and S4 axial surfaces down to the depth of 500 m.
SNSZ
LSZ
Figure 4-24. Visualisation of the domains affected most intensively by late stage deformations D3 and D4. Green surfaces (NE - SW trending) = F3 axial surfaces and D3 shear zones, Brown surfaces = F4 axial surfaces and D4 shear zones. SNSZ = Selkänummi shear zone, LSZ = Liikla shear zone. Top view.
4.3.4 Evaluation of uncertainties
The main uncertainties of the lithological model are presented in Table 4-7. All uncertainties are categorised under two general headings, “conceptual”, referring to uncertainties associated with the conceptual thinking applied in the modelling, and 120
“technical”, referring to the technical uncertainties of the modelling, caused by modelling methodologies and available data. The magnitude of the uncertainty reflects empirical estimation of the importance of the uncertainty on the confidence of the model, and this is naturally related directly to the predictive capability of the model. Low magnitude means that the uncertainty has only a minimal effect on the confidence of the model, whereas high magnitude implies that due to a specific uncertainty, the confidence of the model is lowered and has direct consequences on the predictive capability of the model. Medium magnitude refers that the specific uncertainty has an impact on the confidence, and should be taken into account, although the impact is not considered as major. Table 4-7. Assessment of uncertainties related to the ductile deformation model.
UNCERTAINTY CAUSE MAGNITUDE EFFECT HOW CAN BE RESOLVED? Conceptual Ductile deformation history Conceptual misunderstanding of Low, as the confidence of the Affects directly to the Iterative approach, continuous the deformation history, model seems to explain current lithological model, erroneous checking and adjustment against subjective view, complexity of observations. interpretation of the lithology. new data, if needed. New data the ductile deformation from the investigation trenches and/or extended outcrops.
Effect of folding Folding occurs at Olkiluoto, but Low, as the folding observed in Currently modelled units may be Increasing the resolution of the has not been taken into account the area is predominantly tight, locally erroneous modelling
in the current model. the axial surfaces corresponding 121 mainly to the orientation of the pervasive S2 foliation and, as a consequence, S2 foliation can be considered as the main controlling feature of the ductile deformation.
Technical Orientation and location of Low density of drillholes and Medium in the modelled area, Inaccuracy of the 3D model Drilling of new drillholes to modelled features large distances between high in the areas outside areas of low resolution drillholes 122
4.4 Hydrothermal alteration model
4.4.1 Conceptual model The concept of alteration sensu lato consists of three distinct processes and corresponding products: retrogressive metamorphisms, hydrothermal alteration and surface weathering. From the perspective of the present study and the alteration model, of these three distinct episodes, the focus is on the characterisation of the hydrothermal alteration, as it is the most distinct type of alteration and is considered to have the greatest influence on the properties of the bedrock. In addition, surface weathering is briefly discussed. Hydrothermal alteration processes are estimated to take place at temperatures from 50°C to slightly over 300°C. These processes are considered to be linked with the corrosive H2O-NaCl-CaCl2 heated fluid circulation initiated by the rapakivi granite igneous activity at 1570 - 1540 Ma ago. Typical products of hydrothermal alteration are Fe-sulphides (pyrrhotite, pyrite), clay minerals (illite, smectite-group, kaolinite) and calcite. Surface weathering is a process that affects rocks in situ mineralogically, chemically and mechanically or at the surface. In general, weathering is restricted to the destructive processes caused by temperature changes and corrosion by meteoric waters and atmospheric oxygen. This is the youngest alteration processes at Olkiluoto and is naturally still active. It has presumably its roots back to at least tens of million of years and spatial connection to locations of strong hydrothermal alteration. Based on the grade of alteration, two different types of alteration can be distinguished, a fracture-controlled type and a pervasive (or disseminated) type. The fracture-controlled alteration indicates that hydrothermal fluids have passed through the rock along planar features and alteration is restricted to incipient fractures or narrow zones adjacent to them. This subtype seems to consist of in situ or autochthonous minerals, but in some cases also quite thick possibly allochthonous kaolinite fillings have been observed. The pervasive alteration indicates the strongest type of alteration, which occurs disseminated throughout the rock in addition to the common occurrence in the fractures. Only in a few cases, the pervasive occurrence of alteration can be seen without fracture fillings, or altered fractures are just very few in number. The hydrothermal alteration is schematically connected to main events of the bedrock evolution in Figure 4-25; hydrothermal fluids tend to move upward and outward from their granitic source at depth using porous and permeable parts of the already metamorphosed sedimentary rocks and foliation planes (Figure 4-22E). A layer or unit of impermeable rocks in the sedimentary sequence can cause damming of the hydrothermal fluids, which in the case of overpressure may cause hydraulic fracturing in rocks - hydraulic fracturing commences with pore-fluid expansion at the depth at which fluid pressure just exceeds the sum of confining pressure plus rock strength (Norton 1984, Nelson & Giles 1985). At Olkiluoto, the previous tectonic activity and faulting have developed breccia and gouge as well as extensional fractures. Cohesionless or low-cohesive discontinuities like these have enabled hydrothermal fluids to circulate along old and newly formed fractures. A well-developed fracture and fault zone system provides a network for fluids to pass through and serve a favourable target for alteration phenomena and precipitation. Veins and interstice fillings form in places where the fluids flow through larger, open space fractures and precipitate new minerals along the walls of the fracture, eventually filling it completely. 123
A) C) Sedimentary protolith of Olkiluoto Anorogenic stage and subsequent hydrothermal events gneisses (>1900 Ma) < 1570 Ma Epiclastic and pyroclastic sediments Extensional tectonics: derived from various unknown sources Intrusion of large bodies of A-type granites (1570 - 1540 (Kärki & Paulamäki 2006), mostly pelites Ma): Laitila rapakivi batholith, Eurajoki rapakivi stock, and greywackes possible unexposed bodies (?)
B) Rapakivi granite-induced processes: Svecofennian orogeny (1880 - 1770 Ma) - crystallisation and degassing of magma, retrograde High grade metamorphism & polyphase boiling, separation of vapor and liquid phases ductile deformation and major crustal - ponding of fluids in impermeable rock units causing new growth fracture, breccias and veins (hydraulic fracturing) - upflow of heat and fluids along faults, fractures, and ĺ gneisses, migmatites and anatectites & permeable rock units shearing, folding - circulation of magmatic fluids and particularly meteoric Retrograde phase of metamorphism waters in surrounding gneisses - magmatic fluids ĺ greisen veins and networks ĺ decomposition of cordierite and - hydrothermal heat and fluid circulation ĺ illitisation, plagioclase kaolinisation, sulphidisation and carbonisation, silicification Brittle phase deformation etc. ĺ fractures, faulting D) Late Precambrian and Phanerozoic times ĺ deep weathering and hydrothermal activity: kaolinitic paleosols and fracture carbonisation E)
Figure 4-25. Simplified chronological flow chart of bedrock evolution and hydrothermal activity at Olkiluoto (A-E). Note: E) is a conceptual illustration of phase D) showing pathways and processes of hydrothermal activity linked to rapakivi granites, not in scale in any direction or dimension. 124
4.4.2 Modelling assumptions and methods
The modelling procedure of the alteration is shown in Figure 4-26. The basic principle behind the modelling of the alteration is to define volumes of rock, which have the highest degree of alteration, i.e. which have the highest probability for the occurrence of alteration. The first step (ICP step) is on the definition of altered drillhole intersections (Figure 4-27) and the study of their distributions in 3D. Sections of highest degree of alteration are digitised as vertical profiles (Figure 4-28) and the creation of the final 3D solid is based on the enveloping of drill core intersections with the most extensive sections of alteration, based on the vertical profiles (Figure 4-29).
Figure 4-26. A schematic representation of the workflow in the construction of the alteration model. 125
Figure 4-27. Definition of altered intersections in drill cores and the study of the distributions of the alteration.
Figure 4-28. Digitising altered rock sections by vertical profiles (indicated by the black line). 126
Figure 4-29. Creation of a solid (visualisation) from the digitised vertical sections.
The 3D-modelling is performed by applying drill core length of one metre as reference rock volume of one cubic metre as source information. Correspondingly, the data received from ONKALO tunnel wall mapping, the area of 10 m2 is kept valid for modelling 30 m3 reference rock volume. At the first stage of drillcore logging, the core sections were mapped as hydrothermally altered zones, if there was clear observable pervasive changes in mineralogy or repeated fractures with visible infilling and a minimum drillcore length of 1 m. Later, additional twelve shorter sections were included in the database due to their strong alteration. To describe the grade of alteration, the fracture-controlled and the pervasive (or disseminated) types were distinguished (Table 4-8).
The study of hydrothermal alteration zones suggests an extended and complex history of sequential events (Front & Paananen 2006, Gehör 2007). Different alteration events indicated by specific minerals or mineral assemblages have significant overlap so that the alteration zones of the younger minerals often replace or occupy the older ones. Table 4-8 collects all the alteration zones detected and gives statistical information on the number and length data. At the present, altogether 379 alteration zone intersections have been mapped in 42 deep drillholes. These zones have a total length of 4699 m, which encompasses ca. 24 % of the total drill core length. In single boreholes the amount of the alteration zones varies from as low as 5 % to higher than 50 %. 127
Table 4-8. Statistics of the alteration intersections subdivided and classified according to hydrothermal minerals and style of alteration (fracture-controlled and pervasive). A summary of the drillhole used is presented in last row.
Alteration mineral(s) Style Number Length Median (m) (m) Kaolinite Fracture-controlled 113 1830 10
Pervasive 67 955 11
Illite Fracture-controlled 103 1269 7
Pervasive 133 1834 8
Sulphides ±Quartz Fracture-controlled 54 709 9
Pervasive 38 327 6
Fracture-controlled 6 84 9 Quartz±Sericite±Epidote Pervasive 62 921 12
Drillholes 379 4699 7 OL-KR1 - KR42
4.4.3 Spatial model
The occurrence and distribution of the most pronounced alteration volumes or solids of illite, kaolinite and sulphides in the Olkiluoto site model are shown in Figure 4-33 to Figure 4-40. The solids are outlined so that they try to encompass the strongest alteration and as many of the altered drill core sections as possible. However, the alteration solids contain a lot of rock mass with shows only a slight alteration or no alteration at all.
Compared to the first geological model of the Olkiluoto site (Paulamäki et al. 2006) the shape of the alteration solids have somewhat changed and received new details due to new deep drillholes. New solids also benefit from the development of the conceptual ideas and understanding of the mechanism and events of the hydrothermal alteration. The most prominent modification can be seen in visualisation of the illitic alteration (Figure 4-33 - Figure 4-34) where the previous half-dome or inclined wedge looking solid has turned into two flattened volumes which converge in the northeast. 128
4.4.3.1 Illitisation
Illite, which is expected to be generated a result of more energized hydrothermal fluid circulation than kaolinite, occurs as green, transparent, soap-like mass or it forms grey to green waxy or powdered coverings. In fractures, where illite is the dominating phase, it usually lines the fracture walls, whereas kaolinite typically forms the incohesive infilling. The ONKALO volume appears to have discrete illitised zones, but the drill core data implies that northwards from the ONKALO (Figure 4-33 - Figure 4-34), the bedrock has been affected by advanced illitic alteration.
The illitised zones are characteristically 5 - 20 metres thick in drill core traverses. Figure 4-45 of drill core OLKR8 is an example of drill core sample presentations that illustrate occurrence of pervasive and fracture-related hydrothermal alteration and combine the alteration features detected. The illitisated zones (Figure 4-45, Column 6) coincide in the given example excellently with the water conductivity measurement (column 1) and with sulphide, clay and carbonate accumulations in fracture fillings. In zones, which have experienced advanced illitisation, the rock is yellowish or green coloured and has lost its mechanical strength. Illite occurs often as single alteration product, but often kaolinite, calcite and sulphides accompany it.
Microscope study of pervasively illitisated pegmatitic granite demonstrates that illite may have derived in processes, where Ca-plagioclase and sheet silicates have altered in the course of the fluid-rock interaction. Albitisation increased the calcium concentration of the hydrothermal fluids.
The sheet silicates were totally or partially broken down during the illitisation. Figure 4-30, Figure 4-31 and Figure 4-32 demonstrate a typical feature detected in the pervasively illitised pegmatitic granites, where Ti-oxides tend to accumulate into irregular clusters in the mass of fine-grained illite.
Ti-oxide
quartz
illite
1 mm
Figure 4-30. Microphotograph of pervasively illitized pegmatitic granite. The Ti-oxide occurs as irregular clusters, several millimetres in diameter. Sample OLKR12-672.00. 129
Figure 4-31. La-ICPMS transect profile (green line) through two TiO2 enriched grain aggregates (greyish) that are enclosed by illite (dark grey).
Figure 4-32. A real-time ICPMS-graph illustrating the distribution of Ti (black curve) in the two aggregates in the transect shown in Figure 4-31. The other curves in the graph show the distribution of Zn, V, Ni, W, Fe and Gd through the ablation. La- ablation starts from up left and proceeds to downright in the profile. 130
Figure 4-33. Sections of pervasive (dark green) and fracture-controlled (light green) illitisation in drillholes. The two green blocks indicate the modelled illitised bedrock volumes. Top view.
Figure 4-34. Sections of pervasive (dark green) and fracture-controlled (light green) illitisation in drillholes. The two green blocks indicate the modelled illitised bedrock volumes. View to 030°/-5°. 131
4.4.3.2 Kaolinisation
Kaolinite appears to be an important constituent of the rocks, forming 5 -30 % or locally even more of the volume. The zones, which have encountered kaolinisation, contain various amounts of illite on slickensides and fracture fillings and therefore the appearance of kaolinitic zones in Figure 4-36 - Figure 4-37 demonstrates the zones in which kaolinite is the essential, but not inevitably the single alteration product. The kaolinitic alteration zones constitute numerous spots and lenses (Figure 4-35), which occur at irregular intervals. Their cross cutting lengths usually vary from tens of centimetres to tens of metres in drill core intersections.
In fracture fillings kaolinite forms powdery disseminated white coatings that may well have thickness of several millimetres. These soft fillings are typically loosely attached to the host rock.
The most intensively kaolinitised zones at the surficial slice, which the ONKALO tunnel has penetrated this far, come out as strongly weathered and softened sections. The drill core data and the evidence from ONKALO tunnel point that the kaolinitised sections are located effectively at an upper part of the bedrock. The bedrock block, which has encountered advanced kaolinitisation has, according to the current data, thickness from - 100 to -200 metres measured form the surface (Figure 4-37). This type of kaolinitised bedrock block wedges to a greater depth in northern part of the target area, where the present data (especially the data from the drill core OL-KR13), implies that the base of kaolinitised block situates at the depth of 250 metres. The drill core data reveals numerous disconnected zones at greater depth, but their position remains unclear as the current drill core data from that bedrock area is insufficient.
The observations from the ONKALO-tunnel support the evidence received earlier from the drill core data, that the migration of the fluids responsible for alteration was locally controlled by the anisotropy of the bedrock. Kaolinitic alteration, especially, is found to have concentrated along fracture zones as well as along the lithological boundaries.
Figure 4-35. Advanced kaolinisation in drill core sample OL-KR24 drill core length of 24 m. (red circle surrounds a typical cluster of white kaolinite spots). 132
Figure 4-36. Sections of pervasive (red) and fracture-controlled (yellow) kaolinisation in drillholes. The yellow block indicates the modelled kaolinitised bedrock volume. Top view.
Figure 4-37. Kaolinitised volume is located in the uppermost part of the study area with orientation opposite to the main lithological trend (slightly dipping to N). Red = pervasive kaolinitisation, yellow = fracture-controlled kaolinisation. View to 310°/-5°. 133
4.4.3.3 Sulphidisation
Sulphidisation is recognized as pyrrhotitic dissemination, which comprises the main quantity of that alteration volume, and in lesser degree of pyritic coatings and pyrite vein stockworks (Figure 4-38). Sulphides cover considerable dimensions of the bedrock and pyrrhotite dissemination is particularly connected with graphitic fracture infillings, with mica gneisses and migmatites and with graphitic occurrences and to a degree it is understood to originate back to the primary compositions of the metasediments. Sulphidised wall rocks, usually migmatites, contain several percents of disseminated pyrrhotite, which occurs also in the fractures of those zones. The thicknesses of this type of zones are from centimetres to several metres. Pyrite is common especially in occurrences, which have been subjected under influence of hydrothermal fluid circulation. Typical textural types for pyrite are hair dykes, idiomorphic crystals or spots. It occurs in same assemblages with clay minerals (chlorite, kaolinite, illite) and calcite.
The sulphidisation is mainly located in the SW-edging of the modelled area (Figure 4-39 - Figure 4-40). The drill cores OL-KR-7, OLKR-10 and OLKR-30 disclose the thickest section of the sulphidised bedrock volume. They indicate that the lower limit for the sulphidised zone situates at the depth of -250 to -300 m from surface. The sulphidised zone wedges to shallower depth at the SE-edge of the modelled ONKALO- area bedrock volume. Similarly at the northern part of the area the base of sulphidised zone sets at the level from -50 m to approximately at –200 m. Similarly to the kaolinisation there are numerous disconnected patches outside the modelled block. The bedrock area in question has scanty drill core information and for this reason it is not possible to take into account this data in this preliminary model.
Figure 4-38. Breccia-type pyrite in strongly sheared mica gneiss, OL-KR22, at ca. 390 m. 134
Figure 4-39. Sn dections of pervasive (dark brown) and fracture-controlled (brown) sulphidisation irillholes. The brown block indicates the modelled sulphidized bedrock volume. Top view.
Figure 4-40. Sulphides are located in uppermost part of the model volume following roughly the lithological trend (slightly dipping to SE). Dark brown = pervasive sulphidisation, brown = fracture-controlled sulphidisation. The brown block indicates the modelled sulphidized bedrock volume. View to 310°/-5°. 135
4.4.3.4 Carbonatisation
In several occasions calcite appears to be the closing process of a particular fluid circulation episode. It widely covers the older hydrothermally generated fractures infillings in all levels of the drilled bedrock volume. Furthermore, calcite occurs typically as vein stockworks (Figure 4-41 and Figure 4-42) and forms the matrix for the clay infillings.
The calcitic fracture fillings are more common and the vein networks are dense at the zones, where hydrothermal fluid flow has reworked the bedrock. The drill core data indicates that the zones, which are subjected to hydrothermal alteration, are occupied by late calcite and typically calcite is distributed in broader rock volume than the other hydrothermal products at the alteration zone (Figure 4-45, Table 4-9). Similarly to kaolinisation, illitisation and sulphidisation - carbonatisation has a significant role in alteration incidents and the total volume of calcite in the hydrothermally altered zones appears to be considerable. The incidence of carbonatisation is estimated from the rate of occurrence of calcitic fractures in the drill core. When the individual calcite filled fractures are fixed into connected zones, the carbonatisated sequences in this scheme appear to be more extensive than they are in the case of the other alteration types. However, calcite is uncommon member in unaltered rock. Penetrative carbonatisation of the bedrock itself has not been detected, although the strongly illitised zones locally appear to have a strongly influenced by carbonatization. The carbonate-bearing zones may have thicknesses from few metres to tens of metres in drill core traverses.
Figure 4-41. Set of cross cutting calcite veins connected with the "storage hall fault" on ONKALO tunnel wall. The thicknesses of the calcite veins in Figure are 3 cm at most. 136
Figure 4-42. Crosscutting (white) calcite veins in drill core OL-KR40 at 607 m.
4.4.3.5 Sericitic alteration
Sericitic alteration occurs typically as thin bands and often the fractures, which have sericite as single filling phase are closed. Sericite occurs as either as fine grained mass or it forms coarse flakes, 1-2 cm in size. In drill core samples sericite is not found to occur as pervasive, instead it forms random bands spaced in intervals from few to tens of centimetres and sometimes it is related with other hydrothermal alteration sites. In the ONKALO access tunnel sericitic alteration forms extensive patches and bands (Figure 4-43 and Figure 4-44).
Figure 4-43. Sericitic alteration in ONKALO at chainage 1950 m. 137
Figure 4-44. Coarse sericite on wall of ONKALO tunnel, chainage 1950 m. 138
Figure 4-45. Drill core sample OL-KR8. The fracture mineralogy of the drill core sample demonstrates the occurrence of the main clay types, sulphides and calcite; the thickness of the fracture infilling and the percentage, which is covered by the filling substance, are given in separate columns. Carbonatisation, which is observed from the fracture fillings and from calcite vein stockworks, appears to be the most widely distributed alteration product in fracture walls and fracture fillings. 139
Table 4-9. Explanations for Figure 4-45 columns.
Column Explanation Water conductivity measurement with 2 m packer interval. data from Pöllänen and 1 Rouhiainen 2005 2 Sulphide as monomineralic fracture filling
3 Sulphide fracture filling (thickness of filling on scale 0 - 3 mm) All clay phases in fracture including hydrothermal and secondary phases (thickness 4 scale 0 - 3 mm)
5 Lithology of drill core, see legend for the lithology on the right. Data logged by A. Kärki. 6 Pervasive illitic alteration of the rock Data from K. Front & M. Paananen 2006. 7 Pervasive kaolinite alteration of rock . Data from K. Front & M. Paananen 2006. 8 Fracture density Deformation zone intersection. Brittle fault zone intersection, brittle joint cluster 9 intersection, semi-brittle fault intersection Data from Paulamäki et al 2006. Percentage1 of kaolinite illite of the fracture plain area in drill core section (scale: 0 - 10 100 %)
2 11 Thickness of kaolinite-illite filling in fracture plain area (scale: 0 -3 mm).
1 12 Percentage of illite of fracture plain in drill core section area (scale: 0 -100 %).
2 13 Thickness of illite filling on fracture plain area (scale: 0 -3 mm).
14 Occurrence of calcite as monomineralic fracture filling 1 15 Percentage of calcite of the fracture plain in drill core section area (scale: 0 -100 %).
2 16 Thickness of calcite on fracture plain in drill core section (scale: 0 -3 mm) 17 occurrence of chlorite in fracture plain 18 occurrence of quartz in fracture plain 21 occurrence of graphite in fracture plain 22 occurrence of sericite in fracture plain 23 occurrence of corrosion on fracture plain 24 Indication of flow marks on fracture plain
4.4.3.6 Mineralogical properties of the gouge fillings
The mineralogical study of the gouge fillings has been investigated from eleven samples, chosen from Onkalo tunnel lentghs of 68 m, 70 m, 81 m, 87 m, 130 m, 295 m, 409 m, 522 m, 901 m, 957 m and 960 m (Gehör 2007) proves that the main gouge mineral phases in these samples are quartz, chlorite-group phases, illite, kaolinite, montmorillonite (smectite group), calcite, and feldspars. Bulk rock XRF analysis for the < 2 µm fractions show comparatively wide bulk compositional variation, first of all in relation with SiO2, Al2O3 and K2O. 140
The 2 - 20 µm and 20 - 63 µm gouge filling fractions generally contain the same phases as the < 2 -micron fraction, but the X-ray patterns prove that differences exist in mutual proportions of the clay species between the fault zones. There exists a tendency that along with increasing grain size the amount of clay minerals decreases and the mineralogical character of sheet silicates changes. Accordingly, the abundance of quartz and carbonates rises in coarse fractions.
4.4.4 Evaluation of uncertainties
The main uncertainties of the brittle deformation zone model are presented in Table 4- 10. All uncertainties are categorised under two general headings, “conceptual”, referring to uncertainties associated with the conceptual thinking applied in the modelling, and “technical”, referring to the technical uncertainties of the modelling, caused by modelling methodologies and available data. The magnitude of the uncertainty reflects empirical estimation of the importance of the uncertainty on the confidence of the model, and this is naturally related directly to the predictive capability of the model. Low magnitude means that the uncertainty has only a minimal effect on the confidence of the model, whereas high magnitude implies that due to a specific uncertainty, the confidence of the model is lowered and has direct consequences on the predictive capability of the model. Medium magnitude refers that the specific uncertainty has an impact on the confidence, and should be taken into account, although the impact is not considered as major. Table 4-10. Assessment of uncertainties related to the alteration model.
UNCERTAINTY CAUSE MAGNITUDE EFFECT HOW CAN BE RESOLVED?
Conceptual
Type of alteration Current distinction to pervasive Medium The extent of alteration is more Assessment of the fracture- and fracture-controlled types, the extensive as modelled currently, controlled alteration data in modelled volumes refer mainly as the alteration likely continues more detail manner and the to pervasive types as fracture-controlled outside the evaluation of its impact to the modelled volumes. Yet, the location of more extensive pervasive alteration is alteration. considered as the property of the rock, fracture-controlled alteration as a property of fracturing. 141
Location of altered rock within Natural variability of alteration Medium to high The amount of alteration within Assessment of the natural modelled volumes zones, i.e. discontinuous en the bedrock is exaggerated. variability through prediction- echelon and branching patterns outcome-studies and the analysis (related also to the orientation of the controlling features for the and extent of existing fault occurrence of alteration. zones). This is inherently included into the modelled volumes as they describe volumes with the highest probability to contain altered sections. Technical
Existence of unknown alteration Data resolution (i.e. so-called In the modelled area there is a Local features may be Through prediction-outcome zones white areas), orientation bias due low uncertainty that site-scale intersected in unexpected places. studies, i.e. how many unknown to quite uniform drilling alteration zones would exist, but Unlikely to cause any major alteration zones were met orientation for local occurrence of altered problems. compared to the predicted? What sections the uncertainty is were the properties of these considered as medium to high. zones?
Amount and location of altered Data resolution (i.e. so-called Medium in the site area, high The amount of alteration within New investigations, i.e. drillings, rock within the modelled white areas), orientation bias due outside the bedrock may be exaggerated. spectral gamma loggings etc. volumes to quite uniform drilling
orientation 142
Type and intensity of alteration Visual mapping of the drill cores Medium The intensity of alteration may Application of quantitative be variable due to the visual instrumental analysis mapping technique, which is unreliable in the recognition of intensity variations, mineralogical details etc. 143
4.5 Brittle deformation model
The “brittle deformation model” is the name given to the reconstructed 3D arrangement of deterministic brittle and semi-brittle deformation zones in the Site Model volume. The work is based in the first instance on a generic classification scheme (Table 4-11), which in turn is constructed to fulfil certain requirements (Milnes et al. 2007): x it is based on observational features which can be unambiguously and quickly determined “in the field” (during core logging, trench mapping, tunnel mapping, etc., without sophisticated analytical aids) x it has a hierarchical structure which is simple and practical in application x it uses categories which are meaningful for understanding the mode of formation of the zone, underpinned by a scientifically accepted conceptual model
The general background to the conceptual model behind this classification scheme is described in detail in the geological data acquisition report (Milnes et al. 2007) and will not be repeated here. Here we discuss only the relevant categories of the conceptual model, before applying this generic classification to observed conditions at the Olkiluoto site. At the present time, the modelling work concentrates on brittle deformation zones, as described below. A number of semi-brittle deformation zone intersections, have, however, been observed, and will be included in the modelling at a later stage. 144
Table 4-11. Classification scheme for deformation zone intersections now in use at Olkiluoto (see Milnes et al. 2007 for detailed background information).
Designation of a given intersection at Olkiluoto:
The intersection shows intensive deformation, clearly more intensive than the wall rock on either side.
Designation: Deformation zone intersection
The intersection is characterized by features which indicate that the deformation The intersection took place under low PT conditions, retrograde with respect to the high-grade shows the same metamorphic mineralogy of the wall rock high-grade metamorphic mineralogy as the wall rock
Designation: Designation: Low-grade High-grade deformation zone deformation zone intersection intersection
The intersection shows The intersection The intersection The intersection cohesionless or low-cohesive shows fine-grained shows fine- shows medium to deformation products: cohesive grained cohesive coarse-grained gouge, breccia, fractured rock and their deformation deformation cohesive partially or wholly mineralized products (e.g. products (e.g. deformation equivalents (low T mineralization) cataclasites, mylonites, products (e.g. peseudotachylite, phyllonites), blastomylonites, Designation: welded crush which are mylonitic gneisses Brittle rocks), which are strongly laminated and schists), with deformation zone intersection massive and and/or foliated strong foliation of (called “R-structure” or “fracture zone” structureless banded or intersections in earlier Posiva reports) schistose type (Table 2-2, The intersection The intersection RMF=3) shows no clear shows clear signs signs of lateral of lateral movement movement Designation: Designation: Low-grade Semi-brittle ductile Designation: Designation: Designation: deformation deformation High-grade Joint zone, or Fault zone zone, or semi- zone, or ductile ductile joint cluster, intersection brittle fault zone, shear zone, deformation zone intersection intersection intersection intersection
BJI BFI SFI DSI HGI 145
4.5.1 Conceptual model
In Posiva Oy’s classification scheme, brittle deformation zones are characterized by cohesionless or low-cohesive fractures (in rock engineering terminology: discontinuities) and/or cohesionless or low-cohesive fault products (gouge, breccia, crush rock, etc.). Although lack of cohesion is a fundamental characteristic of a brittle deformation zone, through its associated discontinuities and fault products (and the characteristic, which makes “fracture zones” so important for nuclear waste repositories in crystalline rock), also fractures and products which are partially or wholly mineralised are included when they are clearly planes of weakness and/or potential pathways for water flow1. Since the latter properties are impossible to determine objectively in each individual case, and may anyway change with time, it is customary to take a conservative standpoint and regard all fractures and all fault products, which show very low temperature liberalization, whether cohesive or cohesionless at the present time or not, as important for the problem at hand. A brittle deformation zone in the present classification scheme corresponds closely to the so called “R-structures” in the earlier bedrock model at Olkiluoto (e.g. Vaittinen et al. 2003), thus facilitating the transition from the old modelling system, to the new methodology, which is used in this report. As shown in Table 4-11, there are two main types of brittle deformation zones, fault zones and joint zones, and these are treated separately below.
A fault zone, as defined here, is a zone of incohesive or low-cohesive fault gouge, fault breccia and/or crush rock, which is accompanied by slickensided fractures, “damage zones”, wall-rock alteration, and evidence of displacement, indicating lateral movement of the country rock on one side relative to the other side of the zone. Fault zones often show a symmetrical architecture, with a zone of transformation or fault core zone, consisting of incohesive fault products and strongly, incohesively, fractured material (often causing core loss during core drilling), lined on either side by zones of influence or damage zones, usually showing an above-average degree of fracturing and/or other effects due to the faulting process and local conditions (e.g. certain types of fracture, altered wall rock due to increased fluid circulation, “drag” of wall rock structures). A typical feature of the fractures in the core zone and in the zones of influence on either side are striated, slickensided surfaces, formed due to frictional sliding of the fracture walls or fibrous crystal growth during movement of the fracture walls (e.g. Hancock 1985, McClay 1987, p. 84-104). Also, there is sometimes evidence for displacement of the fracture walls relative to each other, such as a misfit of the migmatite heterogeneities, veins, etc., on either side of the fractures or the whole zone. The microtectonics of fault zones can be extremely complex, depending on the size of the displacement and history of movement (e.g. Groshong 1988), and there is often a genetic relationship between older ductile and/or semi-brittle shear zones formed at lower levels in the crust and younger fault zones developed at the same location, under a similar stress regime but at higher levels. In such cases, the earlier fault rocks
1 The current classification scheme applied in Posiva is specifically designed for the use in the context of nuclear waste disposal investigations in crystalline bedrock, where the analysis of the existence of cohesionless fault products is of main importance due to their possible effect on the hydraulic and mechanical properties of the faults. Therefore, the classification is based on the concept of cohesion – non-cohesion; yet, in contrary to Posiva’s classification scheme, in common structural geology usage brittle fault zones may denote to both cohesive or incohesive fault rocks as the cohesion properties of fault rocks carries no information at all on the deformation mechanisms at the time of faulting. Foor a good review on the classification of brittle fault rocks as used in common structural geology, the reader is referred for example to Passchier & Trouw (2005). 146
(mylonites and cataclasites) become brecciated and incorporated in the incohesive fault products. In contrast to joints and joint zones (see below), the fracturing related to fault zones is strongly localized in the damage zones adjacent to the main movement zone (fault core zone) or around the fault tip. Much of the fracturing in the damage zones is thought to represent primary shear rupture (rupture modes II and III, see Engelder 1993), caused by localised high stress concentrations, but stress relations were complicated and changing rapidly with time, causing a whole spectrum of minor brittle structures to form, simultaneously or in sequence. Brittle deformation zone intersections which show some or all of the characteristics summarised above are labelled BFI in the geological database (see Table 4-11).
A joint zone is a narrow zone of closely-spaced joints, i.e. fractures (discontinuities) which show no signs of movement parallel to the fracture surface. “Closely-spaced” in this context means more closely spaced than the average spacing of joints in the surrounding rock (often called “averagely fractured rock” by rock engineers). The most obvious signs of movement, which will be systematically checked (presence/absence) on every fracture, would be (1) slickenside striations on the fracture surface, and (2) a misfit of country rock heterogeneities (e.g. leucosome in migmatites) from one side of the fracture to the other. Lack of these two easily observed features is taken to indicate that the fracture (discontinuity) in question is not a fault but what is called universally a joint in the geological literature. Joints are also identified by a number of positive features, which may or may not be developed in any particular case. These include plumes and fringes, small-scale irregularity (on a scale which precludes lateral movement), occurrence as elements in regionally systematic sets which are not preferably localized near major fault zones. Joint zones may contain fractures which show all these features, but are mainly distinguished from fault zones by the absence of fault gouge, brecciation and other signs of significant relative movement of the wall rock on either side. However, joint zones may be marked by partially or wholly mineralised joints and zones of hydrothermal alteration in the intact rock, in the same way as fault zones. Brittle deformation zone intersections which show some or all of the characteristics summarised above are labelled BJI in the geological database (see Table 4-11).
Jointing is thought to represent extensional rupture under the action of effective tensile stresses (rupture mode I, see Engelder 1993) and joints are of major importance for the performance assessment of deep geological repositories for spent nuclear fuel in crystalline rock, since they are the main type of rock discontinuity (in the terminology of engineering geology, see Hudson & Harrison 1997) and the main type of hydraulically conductive feature (in the hydrogeological terminology applied to fractured crystalline rocks, cf. NRC/CFCFF 1996). However, in contrast to the vast literature on joints and jointing (for review, see Pollard & Aydin 1988), there is practically no literature on joint zones, although it is well known that they exist (e.g. Twiss & Moores 1992, p.38-39, NRC/CFCFF 1996, p. 56-58). In fact, the prestigious committee, which compiled the NRC/CFCFF book, ends its short notice on joint zones as follows: “Available knowledge of the geometry of, and mechanisms for, joint zones is inadequate. Because the contribution of (such) fracture zones to the fluid flow in fractured rocks may be substantial, a better understanding of the subject is needed.” 147
Although not assigned directly to the “brittle deformation zone” category, semi-brittle deformation zones2 are also an important group as many brittle deformation zones have partly semi-brittle character, especially in zones with long-continued or recurring movements. The core zones of semi-brittle deformation zones are occupied by cataclasite and/or welded crush rock, whereas the influence zones are mainly marked by diffuse networks of welded and sealed fractures. The only structural elements which are often distinguishable in the field are the core zone margins, although even these may be difficult to identify and are often irregular. The cores of semi-brittle deformation core zones (cataclasite and welded crush rock zones) are so resistant that they sometimes form positive topographic lineaments, i.e. are more resistant to glacial erosion than the surrounding wall rocks, and are usually at least as tough as the wall rocks during tunnelling. However, neither the zones of influence nor the core zones of these types of deformation zone are in themselves of great significance for rock engineering and hydrogeology, since their properties are usually similar to the wall rock. In addition, semi-brittle deformation zones are not thought to be very common at Olkiluoto, based on present geological knowledge of the site, although a number of intersections (labelled SFI in the geological database) have been observed). Nevertheless, experience shows that, if present, they are prone to continued movement and reactivation under more brittle conditions and thus play an important role in the understanding the evolution of faulting.
Due to lack of general understanding of the geometries and mechanisms for joint zones, as explained above, and due to the observation in Olkiluoto that fault zones are far more common than joint zones, the main emphasis of brittle deformation modelling at present is to identify, characterise and visualise fault zones. Fault zones here refer to geological domains, which are tabular in form, have sub-parallel and sub-planar margins and great lateral extent compared to their thicknesses (cf. Munier et al. 2003). In addition, they show significant lateral displacement on one side of the zone relative to the other side, although this may not be observable (cf. Milnes et al. 2006). The definition “significant displacement” refers to an amount sufficient to produce typical products of fault zones such as cohesionless or low-cohesive breccias and/or gouges, an increased number of slickensides, and complex fracturing not present outside the zone.
Fault zone architecture
As noted above, fault zones can be conceptualised as consisting of one or more fault core zone(s), bounded (or separated) by zones of influence (a term specifically used in Posiva Oy), the latter known generally as “damage zones” in the scientific literature (cf. Milnes et al. 2006), and also as “transition zones” (e.g. Munier et al. 2003). This typical “architecture” is shown schematically in Figure 4-46. As explained above, fault cores consist typically of noncohesive or low-cohesive breccias and gouges and increased numbers of slickensided surfaces and are typically heterogeneous in nature, having discontinuous, en echelon type of geometries, with anastomosing and branching traces.
2 The terminology used in Posiva’s classification scheme is again based on the concept of cohesion – non- cohesion and differs from the common usage in structural geology. In common scientific use the term “semi-brittle” refers to actual deformatin mechanism where part of the rock deformes in brittle fashion and part as ductile. In Posiva’s usage the term refers to rocks which have undergone sealing and cementation during or after the faulting event, resulting in cohesive rock; again, this is justified due to the importance of cohesion to the possible hydraulic and mechanical effect of the faults. 148
This heterogeneity may also lead to the existence of multiple fault cores within one fault zone intersection, with thicknesses varying considerably from one location to another, similarly to the relative proportions of fault breccia, fault gouge and the number of slickensides (the proportions of which have direct influences on the hydraulic properties of faults, cf. NRC/CFCFF 1996).
On each side of the fault core, and separating multiple cores, fault zones are represented by zones of influence (Figure 4-46), in which the deformation during movement was less intense than in the fault core zone(s) and gradually decreased to zero towards the outer margins of the zone. The zones of influence are typically characterized by shear fractures, increased fracturing, en echelon zones of tension gashes and other brittle structures, often in complex arrays, and are also often associated with alteration in intact rock. (cf. Milnes et al. in 2007). In addition, the zones of influence are often seen as geophysical anomalies (particularly on acoustic logs, Long Normal and Short Normal resistivity logs) and are generally more hydraulically conductive than averagely fractured rock (and often than the fault core. Similarly to fault core zones, zones of influence may have greatly varying widths (metre to 100 metre scale) and internal properties from one location to another. The internal geometry of brittle features within the zone of influence is dependant on the type of fault (i.e. normal, thrust or strike-slip fault), on the location around the fault (e.g. tip, wall- and linking-damage zones, Kim et al. 2004) and on the degree of later reactivations. By studying in detailed these structural relations it is possible to place constraints on the direction and sense of fault movement, which is an important aspect of geological modelling.
Subsidiary faults (see Figure 4-46), which are typically associated closely with large fault zones, may be located close to the main fault zone and even within the zone of influence itself, but, based on drillhole data, it is difficult to interpret whether these features are splays of the main fault zone or isolated features. Nevertheless, these subsidiary faults are presented here as an exemplification of the complex and heterogeneous nature of fault zones. 149
Figure 4-46. A conceptual model of the architecture of a single fault zone, consisting of a complex branching fault core zone (indicated in black) and an equally complex zone of influence (whose outer margins are indicated by dashed lines). Note that subsidiary faults may exist close by to the main fault zone and these may either be located within the zone of influence or outside it (surrounded by its own zone of influence), depending on its distance from the main fault zone. This model is derived from examples in the scientific literature (cf. Milnes 2006) but also reflects observations on fault zones at Olkiluoto (cf. Mattila et al. 2007). 150
Deformation zones and single features
A fundamental question in the modelling of deformation zones is of course "what is a deformation zone" and what is the distinction between a "deformation zone" and a "single feature"? This question recently has been elaborated in the Expect-project of SKB, which focused on the recognition of "critical" structures, i.e. discontinuities that may pose a seismic risk to a canister position (Munier 2006, Cosgrove et al. 2006). Seismic risk studies have shown (Munier and Hökmark 2004) that criticality is linked to the size of the features, particularly features with a radius of > 50 metres. As a result of the project, the term deformation zone was extended to encompass all structures imposing a threat to canister integrity, including all single features (fractures, ductile shears) above a specific size (Cosgrove et al. 2006). In contrast, in the current terminology applied by Posiva, the term deformation zone does not include single features, although occasionally single features have been included as deterministic structures in the models. The current approach chosen by Posiva Oy is based on the following rationale: from the practical observation of brittle deformation zones in the Olkiluoto access tunnel up to now, fault zones are far more common than joint zones, and, in addition, long fractures (e.g. fractures crosscutting the whole tunnel perimeter) are more often single-plane faults than single joints. Hence, it is proposed to consider each slickensided fracture which is not located within a modelled fault zone, either site- scale or local scale, as a single feature which may have effect on deposition hole integrity (taking into account both the seismic and hydraulic effect) and which should therefore be assessed from the perspective of long-term safety. The validity of this approach will be evaluated during the on-going Rock Suitability Criteria (RSC) project, which aims to define the suitability of specific bedrock volumes for final disposal, and during on-going Prediction/Outcome (P/O) studies.
4.5.2 Modelling assumptions and methods – fault zones
The general workflow in the modelling of fault zones is shown schematically in Figure 4-47. The basic premise in the approach is that a known geological brittle deformation zone intersection (BFI in the geological database), defined either from drill cores, tunnel walls or surface outcrops (the ICP step in Figure 4-1), should be extended in lateral and vertical directions to construct a modelled brittle deformation zone, by extrapolation using existing geophysical and geological data and correlation with similar BFIs identified in neighbouring drillholes or tunnel walls or surface outcrops (the ECV step in Figure 4-1). Based on the conceptual model described above (cf. Figure 4-46), fault zones are assumed to consist of a core zone, consisting of one or several strands, surrounded by a zone of influence. Therefore, the respective steps for the modelling of these features are included in to the workflow (Figure 4-47) and described in detail in the following sections. 151
Figure 4-47. Schematic representation of the workflow in the construction of the brittle deformation model. The first phase in the modelling of a brittle deformation zone is the definition of the extent of the zone, starting with a particular fault zone intersection (BFI see Table 4-11), extrapolating outwards and correlating with other similar fault zone intersections by using diverse geophysical and/or geological information as the work proceeds.
4.5.2.1 Preliminary definition of brittle deformation zone intersections
As noted above, the first step in modelling of brittle deformation zones is the preliminary definition and classification of brittle deformation zone intersections observed in drillholes, outcrops and the ONKALO tunnel into two descriptive categories, brittle fault zone intersections and brittle joint zone or joint cluster intersections (BFI and BJI respectively, see Table 4-11, which then act as “fixed points” for more detailed definition of fault cores and zones of influence and the following analysis of fault zone geometry. In addition to the brittle deformation zone intersections, an additional category, semi-brittle fault zone intersections, has also been implemented into the system (SFI in Table 4-11), as discussed in the preceding section), as these may have important role in the general understanding of faulting mechanisms in Olkiluoto. Semi-brittle deformation zones represent shearing at an intermediate level in the crust where cataclastic flow and other frictional processes are still the dominant deformation mechanisms. The deforming rock does not lose it cohesion, or it becomes quickly cohesive through the action of circulating fluids and mineral solution/ precipitation (cf. Schmid & Handy 1991).
The practical classification of brittle deformation zone intersections is based on identification of the specific features typical for these categories, as described in the preceding text, from the drillcores, tunnel walls and outcrop surfaces. The definition of the intersection boundaries is based mainly on expert judgement by the mapping 152
geologist(s), although the following underlying principles are used as general guidelines for the data acquisition:
x If a specific interval shows typical brittle fault zone products such as gouge, breccia or slickensides, and/or shows other clear signs of lateral movement, it is assigned as a fault zone intersection (BFI). x If a specific interval shows only a marked increase in the frequency of joints, i.e. fractures showing no lateral movement, without any of the above fault- related characteristics, it is assigned as a joint zone or joint cluster intersection (BJI). x If a specific interval is composed of typical semi-brittle fault zone products, such as cataclasites or welded crushed rock, it is assigned as a semi-brittle fault zone intersection (SFI). x In the field, the preliminary boundaries of the brittle and semi-brittle deformation zone intersections are drawn to enclose the most strongly affected part of the zone, as visually estimated, without any closer analysis. These field-defined boundaries usually correspond approximately to the deformation zone core, but before definitive modelling, further processing and analysis of geological and geophysical data, of both the field-defined intersections and their wider surroundings, is necessary, in order to properly define the core zone and the zone of influence and to determine the true fault zone boundaries.
It should be noted that intersections may indicate that brittle and semi-brittle deformation have both occurred in the same zone, superimposed. Such intersections are called composite deformation zones, but from the point of view of parameterisation the brittle and semi-brittle components are treated separately.
4.5.2.2 Definition of the extent of the zone
In order to define the orientation and extent of a zone passing through a given drillhole, tunnel or outcrop intersection thought to represent a fault zone, a combination of one or all of the following geophysical and geological methods is used, weighed one against the other using expert judgement:
x Mise-à-la-masse measurements (see Appendix II) for a specific brittle deformation zone intersection can be used for the cross-hole correlation of the zone or defining connections to the ground surface and the ONKALO tunnel (see Example 4-1). A moderate misfit for the connection is allowed, i.e. if a known electric connection is at a few metres, or at maximum of approximately ten metres, from a known brittle deformation zone intersection, then the connection is modelled into the intersection instead of the position shown by the potential minimum.
x VSP and 3D seismic reflectors (see Appendix II) can be used in determining the orientation and continuity of certain deformation zones. However, since other geological features such as lithological contacts, sulphide-rich layers and foliation planes may induce seismic reflectors, they must be checked against geological data. The single-hole VSP results are approximated as planar features, giving an initial orientation for the deformation zone observed in the 153
drillhole. Using this orientation, the zone can be extrapolated to neighbouring drillholes. Subsequently, the geological/geophysical data in the neighbouring drillholes must be examined to find possible support for the extrapolation.
x Gefinex 400S (SAMPO) (see Appendix II) electromagnetic soundings may be used for extrapolation of the zones in some cases. The method is sensitive mainly to sulphide- and graphite-rich, electrically conductive features, which may also be controlled by fault zones.
x The mean orientation of measured fault plane orientations within or near to a specific fault zone intersection can be used as an approximation of the orientation of the zone in general, although the uncertainties are considered to be quite high by this method. Most of the fault zones at Olkiluoto, particularly local-scale zones are modelled based on the fault plane orientations of the fault cores (i.e. local-scale zones, see Example 4-2).
x The geometry of a modelled zone which has been constructed in a part of the model volume with good data coverage can be used as a guide for extrapolating into regions without geophysical data, if geologically meaningful.
x In some cases, the monitoring of microseismic events can provide useful supportive data.
x If supported by other data (geophysics and geology), modelled zones can be connected to a known lineament (the applicability of lineament data is discussed in Appendix VI).
The following examples serve to illustrate the type of data and arguments which are used to justify the chosen orientation and extent of modelled fault zones.
Example 4-1
This example illustrates the use of mise-à-la-masse measurements in the cross-hole correlation of a specific zone, BFZ-099, is shown in Figure 4-48. The earthing in this experiment is located in drillhole OL-KR4 at the in-hole length of 759 metres. The section in which the earthing was placed had been defined as a brittle deformation zone intersection during geological mapping, consisting of crushed rock and increased number of slickensides, and characterised by a clear P-wave velocity minimum and Ri- zones. The section was considered to be a part of a larger zone, and therefore electric connections to other drillholes were measured during specific mise-à-la-masse campaigns (Lehtonen & Heikkinen 2004, Lehtonen 2006a & b, Lehtonen & Mattila 2007). The observed electrical connections are shown with different viewing angles in Figure 4-48 A and B. 154
A
B
Figure 4-48. A representation of measured electrical connections (dashed light blue lines) to the earthed section in the drillhole OL-KR4 at along-the-hole length of 759 metres, viewed (A) towards NE and (B) from above, upper part of the Figure is towards N.
The connections acquired from the mise-à-la-masse measurements were further compared to the known brittle deformation zone intersections and the more accurately defined fault core intervals (see next section), and the connections were then fixed to these sections, whilst still maintaining close spatial association with the potential minimums and the geological intersections (see Figure 4-49). The defined connections 155
are considered to be representative of the overall geometry of the zone and can thus be used in the interpolation and extrapolation of the modelled zone, i.e. extending the zone to intersections in drillholes, which were not part of the mise-à-la-masse campaigns or which lacked good electrical connections, and in the definition of corresponding brittle deformation zone intersections. In addition, Gefinex 400S (SAMPO) electromagnetic soundings were used for extrapolation of the zone outside the area covered by drillholes, although it is emphasized that no fixed points occur in these areas and consequently the uncertainties are higher in the extended parts. An example of such an extension, based on the connections and geometry defined by the galvanic connections and the Gefinex soundings, is shown in Figure 4-50A. The modelled zone was also connected to a lineament (Figure 4-50B), as this is supported by the mise-à-la-masse measurements and the overall geometry of the zone.
Figure 4-49. Measured electrical connection (blue curve on the right) from the mise-à- la-masse experiment described in Example 4-1. The potential minimum lies at the depth of 520 – 540 m in drillhole OL-KR1 from the earthed section in drillhole OL-KR4 at the depth of 759 m. 156
A
B
Figure 4-50. (A) A representation of interpolation and extrapolation of BFZ-099, based on the geometry defined by the Mise-à-la-masse connections and Gefinex 400S soundings. The extended fault zone is shown as a brown plane, electrical connections as dashed black lines and Gefinex 400 S soundings as blue parallelograms. View is towards NE. (B) Extrapolation of the modelled zone in (A) to a specific lineament. View is from above, north to top of the diagram.
Example 4-2
The second example illustrates the procedure for modelling fault zones, which do not show any electrical connections or which were not part of any mise-à-la-masse measurement campaigns. These fault zones are based on the extrapolation of mean fault plane orientations in the inferred core zone of the fault and application of other 157
geophysical data. In the previous version of the GSM (Paulamäki et al. 2006), the modelled fault zones were categorized into five separate kinematic fault groups, each having a unique fault-slip orientation. Based on this data, only those geological intersections with the same kinematic character were combined if allowed by the fracture orientations. In the present modelling, the cross-hole correlation of the core intersections is based mainly on fault plane (slickenside) orientations, and kinematic data is used mainly as supportive information. This procedure is based on the concept that fault zones may have reactivated in several different directions at different times. In the previous model, when using only the fracture data in the 3D modelling, the orientation of the modelled zone was assumed to be the same as the average orientation of the fault planes within the whole zone. If a specific fault zone intersection in the drillhole had two (or more) clearly separate slickenside orientations, only one fault was modelled, depending on which orientation was the most distinct, or both (or all) orientations were modelled as separate zones. Drillhole intersections lacking kinematic data (brittle joint cluster intersections) were generally not modelled. However, if there was other supporting data, these intersections could be connected to modelled fault zones.
In the present modelling work, the orientation of the fault zones is based on orientations of slickensided fractures within the inferred core zones of the fault zones, geophysical data and crosshole correlation (the core determination procedure is described in details in 4.5.2.3). There were two different approaches to construct the fault zones, depending on the amount of the data and drillhole geometry:
1. Digitising in 2D sections and triangulation between the digitised polygons into 3D solids (Figure 4-51)
2. Construction of the upper and lower contact planes and triangulation into 3D solids (Figure 4-52). 158
A
B
Figure 4-51.Construction of fault OL-BFZ-041, a) digitising of the vertical polygons according to the data (blue lines), b) completed solid as a result of triangulation between the vertical polygons. The fault is intersected by 8 drillholes: KR2, KR6, KR12, KR13, KR19, KR32, KR41 and KR42. Orientation of the fault is c. 157°/30°. View from the SW. 159
a b
c d
Figure 4-52. Construction of planar fault OL-BFZ012. a) Creation of upper and lower contact planes according to the data (blue lines), b) triangulation of the contact planes, c) triangulation between the contact planes, d) completed solid. Intersection OL-KR27- BFI-8450-9650. The core of the intersection is located at 93.1 – 95.7 m. Dip direction /dip 128/53°.
The basic idea of the modelling is that the faults are planar/semiplanar features. In most cases, their continuity is difficult to estimate. However, the site area is rather densely drilled, whereupon the surrounding drillholes largely control the extent of the faults. In addition, geophysical data and interpretations were used in order to orient the faults and to assess their continuity between the drillholes. In this respect, seismic VSP and mise- à-la-masse have been the most important methods. Generally, VSP and mise-à-la masse results indicate numerous gently dipping features with a dip direction to the SE-S, supporting the geological data (fracturing, foliation).
From the whole population of numerous VSP reflectors, those features actually related to observed deformation zone intersections (in single drillholes), were examined in more details. The reflector planes were extrapolated to neighbouring drillholes in order to find appropriate deformation zone intersections near then (within some tens of metres). On the basis of this cross-hole correlation, several potential VSP-based deformation zones could be determined. Later on, these zones were checked against the geological data.
As presented in Chapter 2.2, an extensive mise-à-la-masse survey campaign has been done in Olkiluoto in order to determine the geometry of certain deformation zones (Lehtonen 2006a,b). The survey reveals numerous galvanic connections between the drillholes, probably dominated by sulphide minerals. However, a portion of them is also 160
related to deformation zone intersections. Mise-à-la-masse has been used as a supporting tool in determining the geometry of several fault zones of the present model. Especially, gently dipping and continuous site-scale fault zones OL-BFZ018, OL- BFZ056, OL-BFZ080, OL-BFZ098 and OL-BFZ099 are strongly based on mise-à-la- masse results. Also, rather strong VSP and 3D seismic reflectors are related to these features.
The following examples (Figure 4-53 A and B) illustrate, how VSP reflectors have been used in orienting the deformation zones and estimating their continuity. Single-hole VSP results are approximated as planar features, giving an initial orientation for the fault core observed in a drillhole. Using this orientation, the zone has been extrapolated to neighbouring drillholes. Subsequently, the geological/geophysical data in the neighbouring drillholes have been examined to find possible support for the extrapolation. 161
KR14 KR8 KR4
BFI
BFI BJI
A
KR19 KR14 KR15 KR13 KR31
KR2 KR32
B
Figure 4-53. (A) Use of VSP reflectors in orienting the deformation zones and estimating their continuity. VSP reflectors from KR4 (intersecting the drillhole at 338 m, orientation 169º/20º), KR14 (intersecting the drillhole at 190 m, orientation 157º/24º) and KR8 (intersecting the drillhole at 564 – 582 m, orientation 170/20). (B) Brittle deformation zone BFZ005 (brown) and VSP reflector elements intersecting KR14 at 439-440 m (blue). Orientation of the reflectors is 159º/36º or 160º/38º, and orientation of the modelled zone is 164º/34º. Orientation refers to dip direction/dip. 162
4.5.2.3 Definition of fault core
Fault cores correspond to drillhole sections, where there is a clear increase in the fracture frequency and/or increase in the number of slickensides, occurrence of crushed rock or gouge material. In addition, minimum in the P-wave velocity is considered to be associated with the occurrence of low-cohesive rocks, i.e. crushed rock or increased fracturing, and thus can be used in the definition the core boundaries.
In the case of many drillhole intervals, it is typical that several possible fault cores may exist (corresponding to splaying of the zone or anastomosing fault architecture), but for the sake of simplicity of the model, only one core is defined by a set of rules:
x In the case of multiple possible fault cores, the most deformed one (by visual assessment) is selected to be modelled, and the deformation intensity defined there by fracture frequency or the number of slickensides, by the length of crushed rock or gouge sections and/or by the length and clarity of P-wave velocity minimum. Despite of these rules, there may be situations where two or more sections with similar intensity of deformation are met, and in these cases the decision of selecting the core is left to the expert judgement of the modeller. These set parameters are not totally independent, as for example, sections of crushed rock or increased fracturing are likely to be seen as a minimum in the P-wave velocity, but, as a combination, these parameters can be used to evaluate the effect of mechanical breaking induced by drilling, as an example.
x If two or more possible cores are located less than 5 metres from each other, these cores may be combined into a single core and, correspondingly, if the distance is more than 5 metres, then only one of these cores should be selected. It is emphasized that this rule does not have any geological connotation and is purely a technical simplification for modelling purposes.
Example 4-3
An example of fault core definition is shown in Figure 4-54, which shows part of the WellCAD data compilation log from drillhole OL-KR4 (interval 735-805 metres). The core has been defined on the basis of the preliminary brittle fault zone intersection, the strong P-wave minimum anomaly, the occurrence of increased fracturing and crushed rock, and the engineering classification-based Ri-zones. Based on this data, the core has been set at the interval 756-764 metres of the drillhole length (shown as dashed lines in the diagram). 163
Figure 4-54. An example of the definition of a fault core, based on geological and geophysical data. The defined fault core intersection is shown with a blacked dashed line. The example is from OL-KR4, from the along-the-hole depth interval 735 to 805 metres. The actual fault core has been defined to the interval of 756-764, based on the preliminary brittle fault zone intersection, occurrence of increased fracturing and slickensides, crushed rock, Ri-sections and P-wave anomalies.
4.5.2.4 Definition of influence zone
This is the first attempt to define the influence zone for the modelled fault cores of the Olkiluoto brittle deformation features, based on data mainly from drill holes. The influence zone has been defined only for the site-scale zones due to the higher confidence of the modelled features and the larger significance of the zones for the repository layout. In addition, the influence zones are more visible and easily identifiable for the larger features.
The term “influence zone” has been taken into use in Posiva Oy as the definition includes additional features to those usually included in the term “damage zone” (for an overview of scientific literature, see Milnes 2006) or the synonymous “transition zone” used by Svensk Kärnbränslehantering AB (SKB) (Munier et al. 2003), which are typically defined by the occurrence of increased fracturing and associated shear fractures. The main properties, which are additionally applied for the characterisation of the influence zones at Olkiluoto, are alteration and hydraulic conductivity.
The following set of rules have been applied for the definition of the influence zones for the site-scale zones, each fault zone intersection (BFI) within the modelled zone being treated separately, case by case: 164
x Sections were fracture frequency has increased compared to the averagely fractured rock around the core are included into the influence zone. A 10 m section of averagely fractured rock mass is considered as the boundary for an influence zone. This rule has no scientific basis but rather a technical argumentation: based on the thermal calculations there needs to be minimum distance of 8-10 m between the canister holes and, as a consequence, in the case of less than 10 metres the place would not be suitable for the deposition anyway. In addition, as it has been demonstrated that the fracture frequency is not always sensitive enough for the definition of the influence zone (Mattila et al. 2007), the occurrence or increase in the number of shear fractures (slickensides) is also considered as a mark of the continuation of the influence zone. Usually the number of shear fractures outside the rock affected by the faulting is very low. x Both pervasive and fracture-controlled hydrothermal alteration may cover the core section and also extend along outside the main core. It is expected that altered parts may be more porous, mechanically different from and hydraulically more conductive than fresh rock, and as a consequence, they may have effect on the location of the repository and canister holes. Consequently, the influence zone has usually been extended to include the whole extent of the alteration associated with the main fault core. However, in the case of very large altered sections, for example pervasive illitisation around the site-scale faults BFZ099 and BFZ002, the whole sections may not have been included into the influence zone, but other characteristic features, like shear fractures, have been the defining feature. x Long Normal resistivity, Short Normal resistivity, and sometimes also P-wave velocity or single point resistance anomalies, are often continuously describing the whole influence zone. The geophysical anomalies reflect the properties of the rock matrix that cannot always be seen clearly with naked eye (e.g. porosity, alteration), so if they are clearly anomalous and continuous the influence zone has been continued to include the whole anomaly. Correlation of P-wave velocity data with geological and hydraulic data indicates that low P-wave values are commonly related to increased (hydraulically conducting) fracturing. Also, electrical minima indicate increased porosity (depending also on the properties of the pore fluid), but also the occurrence of mineral conductors (sulphides, graphite). Frequently, fractured sections include also sulphides. x Hydraulic conductivity is often concentrated on the core sections of the fault zones. However, in certain zones the “secondary” cores and single fractures may be as transmissive (or even more) as the main core and, in these conditions, the influence zone has been extended to include also these features. It should also be noted that, in some circumstances, the influence zone is in fact the main water-conducting zone within the fault zone, and the core may be quite impermeable (e.g. when the fault core contains abundant clay minerals). x As already stated in Section 4.5.2.3, multiple cores may exist within a single zone, and for practical reasons (from the perspective of creating solids), only one of these is usually selected as the main fault core, excluding others by a set of rules. As a consequence, these “secondary” cores are usually included in the definition of the influence zone, yet, a threshold distance of 10 metres is used, 165
i.e. if the “secondary” core is more than 10 metres away from the boundary of the influence zone (as defined by other rules), it is excluded from the zone.
Example 4-4
An example of influence zone definition is presented in Figure 4-55, which shows a WellCAD log of geological, geophysical and hydrogeological data from drillhole OL- KR19, along-the-hole depth interval 435-500 metres, which has been modelled to belong to the fault zone BFZ002. The influence zone has been defined on the basis of brittle fault zone core intersection, engineering classification-based Ri-zones, fracturing and fracture types, mainly slickensided fractures, hydrological conductivity and geophysical anomalies, i.e. acoustic Long Normal and Short Normal minimum.
Figure 4-55. An example of the definition of the influence zone, based on geological, geophysical and hydrological data. The defined influence zone is shown with a black dashed line. Example is from OL-KR19, at the depth interval of 435 – 500 m. The intersection illustrated assigned to modelled fault zone BFZ002.
The influence zone is divided into the lower and upper influence zones on either side of the core (corresponding to what is known as the footwall and hanging-wall damage zones in the scientific literature). The thickness of the lower and upper influence zones is totally dependent on the location of the modelled main core, and, for this reason, may vary quite a bit. Therefore, the most important parameter in describing the influence zone at this stage is the total thickness of the whole zone (the sum of the thicknesses of the lower and upper parts). The core’s relationship to the whole influence zone needs to be analysed further in order to describe the upper and lower zones separately, which is beyond the current model version. 166
The thickness of the influence zone is defined as the sum of the distances from the fault core margins to the lower and upper influence zone margins, measured perpendicular to the orientation of the core. However, it is natural that the thickness of the influence zone varies, depending on the location along the fault (i.e. whether tip-, wall- or linking- damage zone) and this is taken as a conceptual model to accept the natural variability of the zones. However, further analysis, beyond this model version, is needed for the definition of the type of the influence zone in question. In addition, the perpendicular thickness of the influence zone, i.e. the real thickness of the whole zone, can be defined separately for each drill hole intersection taking into account the orientation of the modelled deformation zone in respect to the orientation of the drill hole. As a try-out, the real thickness of the OL-BFZ099’s influence zone intersections was counted. In the example case, the intersection length and the real thickness vary from few tens of centimetres to over seven metres, depending on internal relationship between the orientation of the drill hole and the modelled zone. The total thickness of the fault zone at a given intersection is the sum of the thickness of the lower influence zone, the thickness of the upper influence zone and the thickness of the fault core. The important parameters total thickness of the fault zone and thickness of the fault core are given the symbols T and t, respectively, in the geological data acquisition report (Milnes et al. 2007). In the future, the total thickness of the fault zone together with the thickness of the core will be compared with the known total extent of the whole zone and the rules given for example by Sholtz (2002) will be tested.
For each modelled site-scale zone, a table with the influence zone intersections is composed and presented in the Appendix XI. In the tables the upper and lower limits of the influence zone for each drill hole intersection are defined on the basis of WellCAD- logs, and their along-hole thickness at the drill hole intersection is given. In addition, the characteristics of each drill hole intersection are described in Appendix XI.
Currently, the influence zones are defined for the site-scale zones: OL-BFZ002, OL- BFZ056, OL-BFZ080, OL-BFZ098 and OL-BFZ099. Also, the water conductive feature in the upper part of the Site Area, OL-BFZ018, was considered, but the definition of the influence zone using the above mentioned rules are difficult to apply while close to the surface, due to the generally increased fracturing and hydraulic conductivity in the upper part of the bedrock. Also the influence zone for the vertical zones OL-BFZ053 and OL-BFZ055, located east of the ONKALO tunnel, were studied, but so far these zones are defined as a local zones and they are intersected by too few drill holes to be able to describe the internal characteristics of these zones reliably. The internal characteristics of the influence zones are described in more detail for the above named site-scale zones. The description of each site-scale zone is given in the following sections and in Appendix VII.
4.5.3 Spatial model
The modelled zones are classified into two categories based on their lateral extent: Site- scale brittle deformation zones, which are defined by several drillhole intersections and whose orientation and cross-hole connections are mainly established on the basis of geophysics (see Chapter 4.5.2.2), and local brittle deformation zones, usually based on only a few drillhole intersections, their orientation being mainly based on the orientation of the slickenside fractures in the inferred core zones (since relevant geophysical data is 167
lacking). The modifications done for the zones compared to the last model version (v. 0, Paulamäki et al. 2006) are given in Appendix IX.
Site-scale zones tend to have a large modelled lateral extent and are likely to continue also outside the modelled well-investigated model volume (i.e. volume covered by drillholes, investigation trenches and detailed geophysical surveys), although, due to the lack of supporting data, these features are modelled mainly within the Site Model Volume. It should be pointed out that, from a geological point of view, these site-scale zones do not seem to be as continuous as they look when modelled on the basis of geophysics. Some of these zones intersect drillholes at places where no clear structural intersections which could be labelled (e.g. BFI) were identifiable. Consequently, these zones are most likely segmented, comprising of several separate deformation zone segments connected by individual fractures or sets of fractures, linking the segments in a complex manner. The zones are thought to represent the combined effect of brittle faulting and associated fracturing, water-conductive fractures and mineralisations of conductive minerals. This kind of behaviour of fault zones is typical in nature: fault zones are often segmented and connected in a step-like manner by fracture networks across relay or accommodation zones (see Milnes, 2006 and references therein), and as such, fault zones are typically discontinuous and non-planar.
In contrast to the site-scale features, local fault zones are more constrained spatially and have only a minor extent in the modelled area, i.e. are characterised only by a few drillhole, tunnel or trench intersections, sometimes only one.
The confidence of the zones is defined empirically, based on the amount of supportive data and used modelling methods, and is classified into three different categories: 1. Low confidence, 2. Medium confidence and 3. High confidence. Low-confidence states that the orientation, extent and overall geometry of the modelled zone may deviate greatly from the modelled one, due to lack or scarceness or variable quality of the available data. Medium confidence implies that there is a slightly better control on the extent and overall geometry of the modelled zone, yet the amount of data does not permit the zone to be raised in the class of high-confidence, which refers to zones that are considered to be in good control in respect of their geometry and extent.3
For site-scale deformation zones, the confidence is inherently medium or high, due to multiple intersections and supporting geophysical data and the final judgement is based on the modeller’s assessment on the internal consistency and extent of applied data sets. For local deformation zones, unless proven by e.g. tunnel observations, the confidence is automatically set as low or medium, depending on the number of observed drillhole intersections and the quality of supportive data (again judged by the modeller). In the case of direct 3D-observations, a local deformation zone may be assigned a high confidence. In the following text, the properties of modelled site-scale brittle deformation zones are treated in more detail (see also Appendix VII); descriptions of
3 The nature of the confidence assessment for a modelled zone can be captured by the question, which the modeller must answer zone-by-zone: “How confident you are that the zone exists as you modelled it?”. The answer and the confidence of the zone therefore reflects the amount and quality of the available data and the modellers expert view on concistency of the data, i.e. does various data sets point to a similar conclusion? It is pointed out that the confidence does not imply to the existence of the zone, as the existence of the zone is inherently fixed in the current model once it has been modelled, irrespective of the low- or high-confidence nature of a zone. 168
local deformation zones are presented in Appendix VIII. A statistical treatment of fractures’ properties for selected site-scale zones is given in Section 4.6.3.2.
4.5.3.1 Site-scale brittle deformation zones
OL-BFZ099
OL-BFZ099 is a gently dipping, medium angle thrust fault (Figure 4-56, see discussion of kinematic data in Appendix III), with an approximate dip of 40 degrees towards SE and modelled trace length of 2700 m in E-W-direction and 1700 m in N-S-direction. The fault zone is geologically pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, alteration and varying amounts of incohesive fault breccias and gouges (i.e. crushed rock). According to the RG-classification system (Gardemeister et al. 1976), the core consists of RiIII, RiIV and RiV-sections, i.e. densely fractured sections (RiIII), clay-filled sections (RiIV) and clay structures (RiV). The widths of fault core intersections of the zone vary from 1 to 13 metres, the average width being 4.9 metres. A majority of the core intersections fall into the RiIII-category of the RG-classification, but in few intersections also RiIV and RiV-sections occur. This corresponds to the variation on the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone also shows recurrent movement, in addition to ductile precursors, as shown in many drill core intersections by reactivated cataclasites.
The width of the influence zone of OL-BFZ099 is in average 44.3 m but varies from a maximum of 103 m (KR20) to a minimum of 11 m (KR29). A vertical section of the influence zone is shown in Figure 4-57. The characteristic features of the influence zone are the abundance of slickensides, pervasive illitisation, kaolinisation and sporadical fracture-controlled sulphidisation and, in many cases, subsidiary core sections. In most cases, the existence of slickensides has been the limiting criteria for the definition of the influence zone, although a clear increase in fracture frequency is also a characteristic property of the zone. However, in drillholes KR11 and KR20 only very few slickensides exist and KR29 is an exception, as there are no slickensided fractures. The location of KR29 is furthest to the south and it is possible to argument whether this zone continues there or are we at the tip of the zone, represented by abundant fracturing corresponding to horsetail splay or similar structure. In most drill hole intersections the zone has an increased hydraulic conductivity, mainly in or close to the core sections. However, hydraulic conductivity is not a characteristic feature for this zone. The main rock type of zone is usually veined gneiss and pegmatitic granite. In many cases the core sections are at or close to the contact of these rock types.
The average width of the hanging wall influence zone is 16 m, the highest values being at drill holes KR29, KR1, KR31 and KR5. KR29 was the most southern borehole, a possible tip area, and rest of the boreholes are located at the northwestern part of the investigation area. The average width of the footwall influence zone is 23.1 metres. In general, the footwall influence zone is somewhat wider than the hanging wall’s. 169
A
B
Figure 4-56. A. Brittle fault zone OL-BFZ099, top view; B. View to 045/-05. Site volume is shown as a black rectangle. 170
Figure 4-57. The influence zone of brittle fault zone OL-BFZ099 shown as blue surfaces; the core of the fault is shown as a yellow solid; Easting = 1525500. View is towards W.
OL-BFZ002
OL-BFZ002 is a gently dipping, low angle thrust fault (Figure 4-58 A, B, see discussion in Appendix III), with an approximate dip of 30 degrees towards SE and modelled trace length of 2400 m in E-W-direction and 1300 m in N-S-direction. OL-BFZ002 and OL- BFZ099 are considered as two splays of a one single zone, and they combine into a single zone at the central part of the Site volume (Figure 4-59). Similarly to OL- BFZ099, OL-BFZ002 is geologically pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, alteration and varying amounts of incohesive fault breccias and gouges (i.e. crushed rock). According to the Finnish engineering geological RG-classification system (Gardemeister et al. 1976), the core consists of RiIII, RiIV and RiV-sections, i.e. densely fractured sections (RiIII), clay-filled sections (RiIV) and clay structures (RiV). The widths of fault core intersections of the zone vary from 1 to 8 metres, the average width being 4.3 metres. As for the OL-BFZ099, majority of the core intersections fall into the RiIII-category of the RG-classification, but in few intersections also RiIV and RiV-sections occur. Again, this corresponds to the variation on the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone also shows recurrent movement, in addition to ductile precursors, as shown in 171
many drillcore intersections by reactivated old and welded fractures and cohesive breccias.
OL-BFZ002 is interpreted to be the lower splay of OL-BFZ099. The fault system forms two splays at the northern part of the island but join to form one fault between boreholes KR2, KR12 (two separate fault splays) and KR4 and KR7 (one fault), i.e. in the middle of the island. The influence zones of these two splays are difficult to distinguish from each other at drillholes KR2 and KR12 and, as a consequence, they are quite large at this point. Furthermore, in both cases the separation of influence zones appeared to be quite artificial. The width of the influence zone BFZ002 is in average 43.5 m but varies maximum being 75 m (KR2) and minimum being 11 m (KR29). The width of the main core is in average 4,5 m. The average width (the intersection length at the drill hole) of the upper influence zone is 16,2 m and the average width of the lower influence zone is 22.7 m. In general the upper influence zone is somewhat wider than the lower one. One reason probably is that in some places the two separate splays have in fact one larger connected influence zone. A vertical profile of the influence zone is shown in Figure 4-60. The modelled zone seems to be located close by or at the contact between the gneisses and larger pegmatitic granite body, at least in the central part of the island. In many intersections right at the modelled influence zone the rock type is varying between pegmatitic granite and gneisses. In KR12 the whole zone, including both splays, is located under the large TGG gneiss. However, in KR5 and KR11 no such rock type contact is seen but the whole zone is located at the veined gneiss. The characteristics for this influence zone are the abundance of slickensided fractures, pervasive illitisation and in all cases more than one core section. The existence of slickensided fractures has been the limiting criteria for the influence zone. Also the clear increase in fracturing seems to describe the zone. However, in KR11 only very few slickensided fractures exists and KR29 is an exception with no slickensided fractures. The location of KR29 is furthest south and it can be discussed does this zone continue there or are we at the tip of the zone and there is only fracturing, like horsetail splay, connecting it to the rest of the zone. Also KR11 is located quite far in the northeastern corner of the investigation area and it can be discussed if the characteristics of this zone are less prominent at that location. Alteration is also a characteristic feature describing this zone. It appears either as pervasive illitisation in the host rock around the core or abundant fracture-controlled kaolinisation, illitisation and in some intersections also sulphidisation. In KR12 the pervasive illitisation continues further up to the upper splay, but the influence zone has been limited based on lesser fracturing and especially only single slickensided fractures between the influence zones at 590 – 630 m. However, as mentioned earlier this is very artificial limit and the influence zone could continue here to combine both splays if defining it primary based on alteration. Usually this zone has increased hydraulic conductivity mainly at or close to core sections, but in most intersections also single water conductive features are met in the influence zone, especially in places with pervasive alteration. KR11 and KR3 are exceptions being slightly conductive only at the core. The geophysical anomalies, the acoustic long normal and short normal, are used to characterise and define this zone. In many cases they seem to describe the influence 172
zone as well as core sections. One probable reason for this could be difference in porosity in the altered sections, which might be explanation for the description of the influence zone.
The intersection of KR3 is quite special case in many ways. It has very narrow influence zone (11.5 m) based on slickensided fractures, which has been the special feature for this modelled zone, and used in defining the limits for the influence zone. However, based on pervasive illitisation the influence zone could be from 420 to 502, i.e. altogether 82 metres, which would be the second largest influence zone for the modelled BFZ002. Reason for not to use the alteration as a limiting characteristic is that it is met in many boreholes, but not in all of them, and for this reason is handled more like a second important character together with hydraulic conductivity, while slickensided fractures are the primary character for this zone.
Another drill hole intersections for this zone with narrow influence zone are KR29 (the southernmost drill hole described earlier) and KR11 (35 m), rest of the influence zones are over 30 m. This has probably something to do with the location of the drill hole being further away in northeast. Though, based on one drill hole no definite conclusions about the characteristics of this major zone in the eastern part of the island can be made. 173
A
B Figure 4-58. A. Brittle fault zone OL-BFZ002, top view; B. View to 045/-05. Site volume is shown as a black rectangle. 174
Figure 4-59. Brittle fault zone OL-BFZ002 shown together with OL-BFZ099, view to 070/00. Site volume is shown as a black rectangle.
Figure 4-60. The influence zone of brittle fault zone OL-BFZ002 shown as blue surfaces; the core of the fault is shown as a yellow solid; Easting = 1525500. View is towards W. 175
OL-BFZ098
OL-BFZ098 is a gently dipping thrust fault (Figure 4-61 A and B, see kinematic discussion in Appendix III) with an approximate dip of c. 25 degrees towards SE. It is located subparallel, only some tens of metres above another site-scale fault zone OL- BFZ080. The core of the fault is 0.1 – 2.7 m thick, with a typical thickness of 1 m. Geologically OL-BFZ098 is not as distinct as OL-BFZ099 or OL-BFZ002, which may indicate smaller extent and smaller displacements during the faults evolution. The fault is intersected by 23 drillholes, and in 12 drillholes a previously determined geological intersection (BFI or BJI) was associated with the zone. According to the RG- classification system, the core consists of densely fractured sections (RiIII) and clay- filled sections (RiIV) in most of the intersecting drillholes. Also, hydraulic conductivity is frequently elevated at the main core. Based on Sampo Gefinex results, fault pair OL- BFZ098 and OL-BFZ080 may extend farther in the NW, at least to KR3. This continuation is now indicated as a separate fault OL-BFZ040.
In some drillholes, the fault core is characterized by pervasive or fracture-controlled illitisation, kaolinisation and sulphidisation or weathering. Geophysically, the zone is observed in several drillholes as a P-wave minimum and an electric conductor. Its geometry is strongly based on Mise-à-la-masse results, seismic reflectors revealed by VSP, 3D and 2D reflection surveys and Sampo Gefinex conductors.
The BFZ098 seems to form an upper part of the double-sided fault system together with the zone BFZ080. The lower limit for the influence zone of BFZ098 seems to be difficult to separate, especially in the central and western part of the well-investigated area from the upper influence zone of BFZ080. Accordingly, the influence zone in the eastern part of the well-investigated area seems to be clearly thinner.
This modelled zone has the most drill hole intersections, total 23, but only 22 of them has been considered in the description of the influence zone because the newest drill hole intersection KR42 has not yet been logged similarly with older ones to be included here. The width of the influence zone of BFZ098 is in average 31.4 m but varies maximum being 76 m (KR16) and minimum being 7 m (KR8). The width of the main core is in average 0.9 m but varies between in maximum 2 m (KR12) and in minimum 0.1 m (KR10). The average width (the intersection length at the drill hole) of the upper influence zone is 19.9 m and the lower influence zone is 10.8 m. In general the upper influence zone is somewhat wider than the lower one.
The modelled zone seems to be located mainly at the diatexitic or veined gneiss, but in some places the contact between gneiss and larger pegmatitic granite bodies seems to be close by.
The main defining characteristic for the influence zones in many intersections is a continuous hydrological conductivity both at the core section and in the influence zone. In few drill holes, for instance KR14 and KR27, the influence zone has increased hydraulic conductivity caused by single conductive fractures, often also alteration at the same place, without any signs of larger core sections in vicinity. However, usually the highest conductivity is measured at or close to the core sections. Few exceptional drill holes are KR9 with hydraulic conductivity only at the main core and KR12 with very limited hydraulic conductivity at the core or very close by. A special feature at KR4 is 176
clearly increasing TDS at the modelled drill hole intersection while it disappears in the main core section of the following modelled zone BFZ080. A vertical profile of the influence zone is shown in Figure 4-62. The geophysical anomalies, the acoustic long normal and short normal minimum, are very important tools to define this influence zone. In most cases they seem to describe the influence zone together with the hydraulic conductivity while the fracturing has decreased and no other significant features are identifiable. In addition the geophysical anomalies often continue further down and covers also another zone ending at the end of the lower influence zone for BFZ080. In those cases the lower limit for the influence zone has been artificially cut. Alteration is also a characteristic feature describing this zone. It appears either as pervasive kaolinisation or illitisation around the core or abundant kaolinisation, sulphidisation and illitisation in fractures. A section with pervasive sulphidisation is also met in KR40. Alteration is not seen in the intersections of KR4, KR10, KR14, KR24, KR27 and KR29, i.e. in the ONKALO area, but is abundant east and north of the ONKALO area. Increase in fracturing has not been as clear phenomenon in this zone as it is in BFZ002 and BFZ099. However, a clear increase in fracturing may describe the zone in certain drill holes, but it cannot be taken as a defining factor because it is not always distinctive for this zone. In some drill holes fracturing increases only slightly compared to averagely fractured rock mass. In addition, often the more fractured part of the intersection is concentrated very closely around the core, but still the alteration or hydraulically conductive fractures continue further and the influence zone limit is defined based on them. Also amount of shear fractures, i.e. the slickensided fractures, is not increased as characteristically as it is for the BFZ099 and BFZ002. The slickensided fractures exist and in most cases are concentrated close to the core sections, though single ones can be found in the whole influence zone. In some drill holes, like KR27, there are few slickensided fractures indicating the core section, but no mapped core or Ri-section. As mentioned earlier in the case of KR14 and KR27 drill hole intersections are without any clear core section. The main type of intersections based on Ri-classification is RiIII. In addition, RiIV-class intersection can be found in KR7, KR8, KR25, KR28, KR38, KR39 and KR40. For this modelled zone there is no drill hole intersection, which would belong to class RiV. It is interpreted that this zone has not gone through as much movement neither has been exposed to as much strain as BFZ099 and BFZ002. Generally, the geological logging has described the zone to be either brittle fault zone intersection or brittle joint zone intersection, but in three drill hole intersections, in KR7, KR10 and KR12, located in the central part of the well-investigated area, a high- grade ductile deformation zone intersection has also been mapped in addition to brittle fault zone. The defined intersection in KR1, KR2 and KR39 are very close to the surface and for this reason the upper limit for the influence zone seems to be difficult to define and may seem to be quite artificial, especially in the case of KR39. There are no direct tunnel observations for this fault yet. According to the modelled geometry, the main core would intersect the ONKALO tunnel at chainage c. 3138 – 3141 m. 177
A
B
Figure 4-61. A. Brittle fault zone OL-BFZ098, top view; B. View to 040/-25. Site volume is shown as a black rectangle. 178
Figure 4-62. The influence zone of brittle fault zone OL-BFZ098 shown as blue surfaces; the core of the fault is shown as a yellow solid; Easting = 1525500. View is towards W.
OL-BFZ080
OL-BFZ080 is a gently dipping thrust fault with an approximate dip of c. 20 degrees towards SE (Figure 4-63). It is located only some tens of metres below another site- scale subparallel fault zone OL-BFZ098. The core of the fault is 0.2 – 8.58 m thick, with a typical thickness of c. 1 m. The fault is intersected by 21 drillholes, and in 9 drillholes a previously determined geological intersection (BFI or BJI) was associated with the zone. According to the RG-classification system, the core consists of densely fractured sections (RiIII) and clay-filled sections (RiIV) in most of the intersecting drillholes. Hydraulic conductivity is often also elevated. In three drillholes (KR1, KR13 and KR15) there are no clear geological indications of a deformation zone at the intersections. However, according to geophysical and hydraulic results, slickensided fractures and the general geometry of the fault, it has been delineated also to these drillholes. Based on Sampo Gefinex results, fault pair OL-BFZ098 and OL-BFZ089 may extend farther in the NW, at least to KR3. This continuation is now indicated as a separate fault OL-BFZ040.
There are not many indications of hydrothermal alteration related to the core of this fault. Kaolinisation is most common (pervasive as well as fracture-controlled). Furthermore, there is occasional illitisation and sulphidisation. Geophysically, the zone is observed in several drillholes as a P-wave minimum and an electric conductor. Its 179
geometry is strongly based on Mise-à-la-Masse and Sampo Gefinex results and several VSP reflectors. The seismic reflectors detected from the ground surface are strongly concentrated to the upper fault zone OL-BFZ098.
The BFZ080 seems to form a lower part of the double-sided fault system together with the zone BFZ098, and the separation of influence zones between BFZ098 and BFZ080 appeared to be quite artificial in many places.
This modelled zone has totally 21 drill hole intersections, but only 20 of them have been considered in the description of the influence zone because the newest drill hole intersection KR42 has not yet been logged similarly as older drill holes to be included here. The width of the BFZ080 influence zone is in average 30.25 m but varies maximum being 82 m (KR13) and minimum being 7.5 m (KR14). The width of the main core is in average 2 m. The average width (the intersection length at the drill hole) of the upper influence zone is 12.3 m and the lower influence zone is 16.4 m. In general the lower influence zone is somewhat wider than the upper one. A vertical profile of the influence zone is shown in Figure 4-64.
The modelled zone seems to be located only in few drill hole intersections, at KR25, KR27 and KR28, entirely at one rock type, i.e. at veined gneiss. In most cases it is located in the contact of gneiss respective large body of pegmatitic granite and in many cases the rock types are varying intensively in the contact area.
The main defining characteristic for this influence zone is the hydrological conductivity both at the core and in the influence zone. The highest values are usually in the core section, but clearly elevated values are seen in the influence zone as well. A special case is KR8 where there is no hydrological conductivity at the most crushed section (RiIV), but conductivity is concentrated more or less into the RiIII-classified sections around the main core. Furthermore, only minor elevation or no hydraulic conductivity at the core section at KR12, KR15, KR27, KR39 and KR40 is met. These sections have still been interpreted to belong to this zone mainly based on geometry and other properties of the zone. The modelled intersection at KR27 is located at the end of the drill hole and the zone seems to continue further and reasoning has been that it can be conductive further down.
KR8 is a special case in other respect as well, as the TDS-value seems to clearly increase at the core section in 550 m. The same phenomenon is met also in KR29 and KR38. Vice versa, in KR4, the measured TDS-value decreases back to the normal level in the influence zone of BFZ080. The increase in the same drill hole was detected in the upper zone BFZ098.
The geophysical anomalies, the acoustic long normal and short normal minimum, are very important tools to define this influence zone. In most cases they seem to describe the influence zone together with the hydraulic conductivity while the fracturing has been decreasing and there is no other significant features identifiable. In general the geophysical anomalies are often very continuous covering also the upper zone BFZ098. In those cases the upper limit for the influence zone has been artificially cut.
Alteration is also a characteristic feature describing this zone. It appears either as pervasive kaolinisation (KR1, KR2), illitisation (KR4, KR8, KR10, KR38, KR39) or sulphidisation (KR39) around the core or abundant fracture controlled kaolinisation and 180
sulphidisation. Alteration is not met at all in KR14, KR24, KR25, KR27 and KR39. In few cases, like in KR1, alteration has been the main characteristic of the zone and defines the influence zone.
The increase in fracturing has not been as clear phenomenon in this zone as it is in BFZ002 and BFZ099, but in many boreholes it is more prominent than in BFZ098. However, a clear increase in fracturing may describe part of the influence zone in certain drill holes (KR7, KR9 and KR38), but it cannot be taken as a defining factor because it is not always distinctive for this zone. In some drill holes fracturing increases only slightly compared to averagely fractured rock mass. In addition, often the more fractured part of the intersection is concentrated very closely around the core, but still the alteration or hydraulically conductive fractures for instance continue further and the influence zone limit is defined based on them. Also amount of shear fractures, i.e. the slickensided fractures, is not increased as clearly characteristically as it is for the BFZ099 and BFZ002, however. The slickensided fractures are in most cases concentrated close to the core sections, though certain intersections have been defined based on their abundance. The very special cases are intersections at KR1 and KR38 without any mapped slickensided fractures.
The main type of intersections based on RG-classification is RiIII. In addition, RiIV- class intersection can be found in 6 of 20 intersections (KR7, KR8, KR29, KR38, KR39 and KR40). For this modelled zone only drill hole intersection at KR38 has a short section, which belongs to class RiV. In addition, the modelled intersection at KR1 and KR15 has no core section defined.
Generally, the geological logging has described the zone to be either brittle fault zone intersection or brittle joint zone intersection, but in one drill hole intersections, in KR13, a semi-brittle deformation zone intersection and in KR2 and KR12 a high-grade ductile deformation zone intersection has been mapped in addition to brittle fault zone and brittle joint zone intersections. At the modelled intersection in KR23 and KR27 no geological core section has been defined.
As a whole the intersection at KR14, in the central part of the investigation area seems to be minor and quite insignificant with very little hydraulic conductivity and very few fractures. Instead, the intersection at KR29 and KR38 are significant based on existence of RiIV-classified core section in addition to many RiIII-sections, clearly increasing fracturing and elevated hydraulic conductivity. In KR29 (the southern most drill hole) also increased number of shear fractures exists.
There are no tunnel observations of this fault zone yet. Based on the modelled geometry, the fault would intersect the tunnel at chainage c. 3290 – 3293 m. 181
A
B Figure 4-63. A. Brittle fault zone OL-BFZ080, top view; B. View to 045/-25. Site volume is shown as a black rectangle. 182
Figure 4-64. The influence zone of brittle fault zone OL-BFZ080 shown as blue surfaces; the core of the fault is shown as a light-brown solid; Easting = 1525620. View is towards W.
OL-BFZ018
OL-BFZ018 is a gently dipping thrust fault with an approximate dip of c. 15 degrees towards SE. The core of the fault is 0.1 – 4 m thick with increased fracturing and occasional slickenside fractures. The fault is located just some tens of metres above fault OL-BFZ056 and is subparallel to it. Alteration data related to this zone is rather contradictory, however, mostly fracture-controlled kaolinisation, illitisation and sulphidisation are observed. In places, the alteration is also pervasive. The fault is intersected by 20 drillholes. The core is characterized by brittle fault intersections or RiIII-IV-sections in 14 drillholes. In 6 drillholes (KR14, KR23, KR28, KR31, KR35 and KR36) significant geological evidences are lacking, however the fault is delineated to them according to its general geometry and geophysical results. In most drillholes, the core of the fault is also hydraulically conducting. Geophysically, the fault can be observed frequently as a P-wave minimum and an electric conductor. Geometry of the fault is based mainly on combining Mise-à-la-masse and VSP results to geological observations in the drillholes.
In the ONKALO tunnel, the fault can be observed at the chainage of c. 950 – 963 m, related to a long brittle fault intersection, located at 931.90 – 963.00 m. The intersection 183
angle between the fault and the tunnel is rather oblique. The fault intersection is undulating, slickensided and contains 3-40 cm thick fillings of chlorite, clay, pyrite, calcite, graphite, and kaolinite. In the thickest parts, the filling contains some broken rock fragments and thick clay fillings. The fault is also hydraulically conductive.
No influence zone has been determined for this zone. 184
A
B
Figure 4-65. A. Brittle fault zone OL-BFZ018, top view; B. View to 045/-25. Site volume is shown as a black rectangle. 185
OL-BFZ056
OL-BFZ056 is a gently dipping thrust fault with an approximate dip of c. 10 - 15 degrees towards SSE (Figure 4-66). The fault is located just some tens of metres below fault OL-BFZ018 and is subparallel to it. The core of the fault is 0.1 – 1.4 m thick with increased fracturing and slickenside fractures. The core zone is also frequently hydraulically conducting. Alteration data related to this zone indicates fracture- controlled kaolinisation, illitisation and sulphidisation. Occasionally, illitisation is also pervasive. The fault is intersected by 21 drillholes. The core is characterized by brittle fault intersections, RiIII-IV-sections or core loss in 13 drillholes. In 8 drillholes (KR2, KR10, KR12, KR14, KR25, KR37, KR9 and KR4) significant geological evidences are lacking, however the fault is delineated to them according to its general geometry, geophysical and/or hydraulic results. Geophysically, the fault can be observed frequently as a P-wave minimum and an electric conductor. Geometry of the fault is based mainly on combining Mise-à-la-masse results to geological observations in the drillholes and in the ONKALO tunnel.
The BFZ056 is located in the lower part of the “surface bedrock”. Above the zone rock is often clearly more fractured and the hydraulical measurements shows almost a continuously hydraulically conductivity. Underneath this zone rock becomes less fractured and hydraulically conductive. This phenomenon is valid especially for the ONKALO area of the zone (drill holes KR4, KR14, KR22, KR23, KR25, KR28, KR31, KR36, KR38). Probably because of this phenomenon the lower limit for the influence zone was usually easier to define than the upper limit. A vertical profile of the influence zone is shown in Figure 4-67.
This modelled zone has many drill hole intersections, total 21, but only 18 of them have been considered in the description of the influence zone because there was some part of the data missing in the dismissed drill holes. The width of the influence zone of BFZ056 is in average 16 m but varies maximum being 40 m (KR11) and minimum being 4 m (KR24 and PH5). In general the lower influence zone is somewhat wider than the upper one. Commonly the whole influence zone is wider in the eastern part of the investigation area (KR11, KR9, KR27 and KR31 and KR22) than in the central part of the investigation area above the ONKALO.
The modelled zone seems to be located mainly at the diatexitic or veined gneiss, but in few places the modelled main core section is located at the contact between either of gneisses and pegmatitic granite bodies.
The main defining characteristic for this zone is elevated hydrological conductivity both at the core and in the influence zone. Some of the drill hole intersections are geologically clear zone intersections and some are geologically insignificant, but have a clearly elevated hydraulic conductivity, like KR4, KR14 and KR37. In five drill holes, KR4, KR9, KR31, KR37 and KR38, the hydraulic conductivity is not only concentrated on the core sections but also distributed along the whole influence zone. Usually the highest hydraulic conductivity is at the core sections and close by in the influence zone. In addition also altered sections have often elevated hydraulic conductivity compared to the unaltered rock.
Alteration in this zone appears as all types of alteration from fracture alteration to pervasive alteration. The most altered drill holes are KR11 (pervasive illitisation and 186
kaolinisation), KR22 (pervasive sulphidisation and fracture kaolinisation), KR30 (pervasive kaolinisation and fracture illitisation, KR36 (pervasive sulphidisation and fracture illitisation) and KR27 (pervasive illitisation). Drill holes KR11, KR22 and KR27 represent the eastern part of the well-investigated area and KR30 and KR36 are located on the central investigation area above the ONKALO volume. However, the most common feature is no alteration at the drill hole intersections (KR4, KR14, KR24, KR25, KR28, KR31 and KR37) of this zone in the central part above the ONKALO area.
A slight increase in fracturing is clear in every drill hole along this zone, but mainly significant increase in fracturing is seen only around the core sections. Slickensided fractures are met in all other drill holes except KR4, KR23 and KR30, i.e. in some drill holes in the central part of the area. The slickensided fractures are in most cases concentrated close to the core sections, though single ones can be found in the whole influence zone.
The geophysical anomalies, the acoustic long normal and short normal minimum and single point resistance minimum are very important tools to define this influence zone. In most cases they seem to describe the whole defined influence zone. The P-wave velocity is mainly describing the core sections.
Generally, based on geological core logging, the drill hole intersections represent brittle deformation zone and in one drill hole, KR4, high-grade shear zone intersection has been met. Based on rock engineering classification these intersections are usually classified as RiIII-sections, but in two drill holes, KR11 and KR36, also RiIV-sections are met.
It is kept in mind that the defined intersections in KR10, KR11 and KR12 are very close to the surface and for this reason some part of data is missing and can also be misinterpreted.
The influence zone in drill hole KR27 is especially difficult to define because of continuously increased fracturing, existence of slickensided fractures and many core section in this part of the drill hole. This is probably an effect of the modelled vertical zones in this area and makes the definition of influence zone uncertain. However, the orientation of fracturing has been taken into account while defining the zone.
The fault intersects the ONKALO tunnel with an oblique angle at chainage c. 1045 m related to a brittle fault intersection ONK-BFI-104500-110850. The core of the zone is 10-20 cm wide and consists of a main fracture/fault that can be followed in both tunnel walls. The affected zone is over 5 m wide though, consisting of conjugate fractures. The main fracture is hydraulically conductive. Within the whole intersection (1045 – 1108.5 m), there are many other long and sub-horizontal fractures in the zone and several shorter vertical fractures that join the horizontal ones. 187
A
B
Figure 4-66. A. Brittle fault zone OL-BFZ056, top view; B. View to 045/-15. Site volume is shown as a black rectangle. 188
Figure 4-67. The influence zone of brittle fault zone OL-BFZ056 shown as blue surfaces; the core of the fault is shown as a light-brown solid; Easting = 1526700. View is towards W.
Figure 4-68. Site-scale fault zones shown as light-brown solid and the site volume as a black rectangle. View is towards NE at and angle of –20 degrees. 189
4.5.3.2 Local brittle deformation zones
Local brittle deformation zones are presented in Figure 4-69A and B and described in more detail in Appendix VIII. A total of 84 local-scale faults have been modelled.
A
B
Figure 4-69. Local brittle deformation zones (A) viewed to 045/-30 and (B) in a vertical profile, view is towards E, Easting = 1525600. 190
4.5.4 Evaluation of uncertainties
The main uncertainties of the brittle deformation zone model are presented in Table 4- 12. All uncertainties are categorised under two general headings, “conceptual”, referring to uncertainties associated with the conceptual thinking applied in the modelling, and “technical”, referring to the technical uncertainties of the modelling, caused by modelling methodologies and available data. The magnitude of the uncertainty reflects empirical estimation of the importance of the uncertainty on the confidence of the model, and this is naturally related directly to the predictive capability of the model. Low magnitude means that the uncertainty has only a minimal effect on the confidence of the model, whereas high magnitude implies that due to a specific uncertainty, the confidence of the model is lowered and has direct consequences on the predictive capability of the model. Medium magnitude refers that the specific uncertainty has an impact on the confidence, and should be taken into account, although the impact is not considered as major. Table 4-12. Assessment of uncertainties related to the brittle deformation zone model.
UNCERTAINTY CAUSE MAGNITUDE EFFECT HOW CAN BE RESOLVED?
Conceptual
Width and properties of fault Natural variability from one Medium The properties of modelled fault More detailed analysis of cores location to another - there may cores may vary greatly from the drillcore samples and more even be sections with poorly observed - fault core may even specifically, drillhole TV-image. developed core - unevenly be poorly developed or Analysis of the natural distributed drillholes, multiple nonexistent. variability through prediction- core situation. In addition, the outcome studies. Natural current model is a simplification analogue studies in the tunnel. of the fault core. Mechanical breaking during drilling may cause additional uncertainties. 191
Width and properties of Natural variability from one Medium The properties of modelled More detailed analysis of influence zones location to another - there may zones of influence may vary drillcore samples and more even be sections with poorly greatly from the observed - zone specifically, drillhole TV-image. developed zone on influence - of influence may even be poorly Analysis of the natural unevenly distributed drillholes developed or nonexistent. variability through prediction- outcome studies. Natural analogue studies in the tunnel.
Semi-brittle fault zones are more Masked by fault zones Medium uncertainty, as these The effect is considered as small Through prediction-outcome abundant than currently assessed have been observed sporadically. as semi-brittle fault zones are studies - assessment whether we cohesive and may approach the can observe any semi-brittle strength of the wall rock. Relates fault zones in the tunnel. more to the understanding of faulting mechanisms and the geological evolution of the site. Joint zones are more abundant No proper tools for the The uncertainty is considered Local, unexpected joint zones Through prediction-outcome than currently assessed identification, masked by fault low for possible site-scale joint may be intersected, but the effect studies - assessment whether we zones zones, but may be medium for is considered as small. can observe any joint zones in local joint zones. In addition, the tunnel. local joint zones may be associated with site-scale fault zones, but by current techniques, one cannot distinguish these.
Technical
Orientation of the deformation Unevenly distributed drillhole High for local deformation There may be local features Assessment of multiple data zones locations, largely due to zones, low to medium for site- which are intersected by the sources, e.g. surface and infrastructure and safety factors. scale deformation zones, varies tunnel in locations which were drillhole-based geophysical data,
Mise-à-la-masse measurements from one location to another due not predicted by the current assessment of the validity of 192 may indicate simple galvanic to the uneven distribution of models. Unlikely to cause any modelling methodologies connections, without any drillholes. major problems. through prediction-outcome connotation to deformation study zones.
Extent of modelled zones Unevenly distributed drillhole Low for the site-scale There may be local features Acquiring new data from low- locations, largely due to deformation zones within the which are intersected by the confidence areas, assessment of infrastructure and safety factors. modelled area, medium to high tunnel in locations which were fault-scaling laws (although this Lower data resolution. outside. Medium to local-scale not predicted by the current is highly speculative when deformation zones (dependant models. Unlikely to cause any taking into account recurrent on the orientation uncertainty of major problems. movements within the zones, the zones) yet, may give indications on the size distributions) Location of modelled zones Natural variability of fault zones, Medium for site-scale features Unexpected locations of Applying indirect measurement i.e. discontinuous en echelon and between drillholes, close by to modelled zones, especially in techniques such as 3D-seismics. branching patterns (related to the drillholes the uncertainty is low. volumes long distances away Assessment of the natural orientation and extent of the For local deformation zones the from drillholes. variability through prediction- zone) uncertainty is from medium to outcome-studies. high, although low close by the drillhole.
Surface exposures of the Low outcrop density due to thick Medium effect, likely to be Poor correlation of 3D- Excavation of trenches, modelled deformation zones and extensive quaternary higher for local deformation deformation zone model to the assessment of lineament data (related to the orientation and sediments overlying the bedrock zones. surface, decreasing the extent of the zones) confidence of certain zones.
Existence of unknown Data resolution (i.e. so-called In the modelled area there is a Local features may be Through prediction-outcome 193 deformation zones white areas), orientation bias due low uncertainty that unknown intersected in unexpected places. studies, i.e. how many unknown to quite uniform drilling site-scale deformation zones Unlikely to cause any major deformation zones were met orientation would exist, but for local problems. compared to the predicted? What deformation zones the were the properties of these uncertainty is considered as zones? In addition, changing the medium to high. The orientation drilling orientation for some new of the drillholes mask more drillholes could provide more efficiently N-S-striking features. information on the possible masking effect. 194
4.6 Selected fracture statistics
4.6.1 Overview and data sources
Extended fracture data processing and statistical modelling of fractures in Olkiluoto bedrock are presented by Hermansson et al. (in prep.). Hermansson et al. (in prep.) used data sets which included fracture data from the ONKALO-tunnel, outcrops, investigation trenches, and deep drillholes. A statistical model of fractures based on the fracture data from investigation trenches OL-TK7 and OL-TK11, drillholes OL-KR24 and ONK-PH1 and ONKALO chainage PL0 – 140 m has been created by Tuominen et al. (2006) for DFN modelling of the ONK-PH2 area. A preliminary version of the fracture database from deep drillholes is handled and analysed by Kuusisto et al. 2007 who employed data excavation methods such as episode searching methods and decision trees.
In this chapter, some selected analyses and visualisations of the fracture data from drillholes OL-KR1 - OL-KR40 are presented, with the first section focusing on the fracturing as a bulk property of the site and the second section as a property of specified volumes (fault zones).
All the fracture data must be reviewed with the knowledge of decreasing drillhole density as a function of depth and to depict this, drillhole density was calculated for 10- m horizontal sections and is presented in Figure 4-70. In correlation to the decrease in the amount of data as a function of depth, the uncertainties of interpretations based on the drillhole data also decreases with depth. In the upper parts of the site approximately 400 metres of drillhole is included in one 10-m section and on the level of -400 metre the corresponding amount of drillhole metres is still 250 metres. From the level -400 to the level -500 m, the total drillhole length strongly decreases and between the levels - 500 and -1000 metres, only an average of 60 metres of drillhole exist inside a 10-m section. The total number of fractures mapped in OL-KR1 - OL-KR40 is 45 899. 195
Drillhole lengths per 10-m horizontal sections
500
450
400
350
300
250
200 Meters of drillhole of drillhole Meters
150
100
50
0 -1100 -1000 -900 -800 -700 -600 -500 -400 -300 -200 -100 0 Depth (m)
Figure 4-70. The number of drillhole metres in 10-m horizontal sections presented as a function of depth.
4.6.2 Methods
Fracture data was analysed and visualized in an experimental way by using Statistica®- and Microsoft Excel®-programs. Analyses were done with the whole data set but also with special emphasis on subsets limited to fractures belonging to the influence zones of fault zones. Different distributions and dependencies were analysed, concentrating mainly on geometrical fracture properties, fracture filling mineral data, and different fracture classifications. The classifications used here are based on the original mappings and later detailed fracture mineral mappings of drill cores. The abbreviations used in the chapter are explained in Table 4-13. 196
Table 4-13. Explanations for abbreviations of fracture classifications in the fracture database.
Abbreviation Explanation Group op open, rusty/limonite covering group of items called “fracture types” in the Figures ti tight, no filling material fi filled fisl filled slickenside grfi grain filled clfi clay filled plan planar group of items called “fracture shape” in the Figures irre irregular curv curved roug rough; JRC 15-20 group of items called “fracture roughness” in the Figures srou semirough; JRC 7-14 smoo smooth; JRC 0-6 CRUSH crushed rock group of items called “lithology” in the the Figures DGN diatexitic gneiss GRF graphite seam MDB diabase MFG mafic gneiss MGN mica gneiss PGR pegmatitic granite QGN quartz gneiss SGN stromatic gneiss TGG tonalitic granodioritic granitic gneiss VGN veined gneiss fracture zone in penetratively group of items called “general geological altered/weathered host rock/rock fracture types” in the Figures fw environment fracture zone or crushed rock. Host fz rock/parent rock is not weathered or altered hd hair dyke kt break palaeo fracture/ fracture filled with a hard, pf dense mineral infill sf single fracture ss single/individual fault/shear fault zone; zone of multiple subparallel sz faults of unknown age and origin 197
curved, wavy or undulating fracture wall group of items called “geological c without sharp edges. fracture types” in the Figures fracture, totally filled with soft materials, f eg. clay minerals. slickenside, a polished and often smoothly h striated surface of brittle fault. dyke or paleofracture filled with hard, j cohesive materials, eg. quartz or carbonates breakage, a surface with sharp edges and m cleaved mineral faces q unknown infill t planar fracture wall w weathered fracture wall
Fracture orientations have been measured by using drillhole wall imagery and a total of 34 353 measurements were taken as a part of the structural mapping of Olkiluoto drill cores in 2005-2006. For the drillhole fracture data, a correction of direction distribution bias, caused by one-dimensional sampling in the three-dimensional fracture system (Terzaghi 1965), has been used.
4.6.3 Results
4.6.3.1 Bulk fracture properties
The average fracture density (P10) from deep drillholes at the Olkiluoto site is 2.20/m. The bedrock volume including all drillholes was divided into horizontal sections with 10 m thickness and the P10–value was calculated for each section by dividing the fracture number with total drillhole length inside the section. P10 values of the horizontal sections and the moving average are plotted to Figure 4-71; in the upper parts of the bedrock fracture density is approximately 3/m whereas in the deeper parts the fracture density clearly decreases to approximately 2/m. The effect of site-scale fault zones can be seen between -200 - -400 metre where P10 is nearly 2.5/m again. Below this anomaly, fracture density settles down to about 1.8/m. Below a depth of of –400 m, fracture density is very sensitive to fluctuations due to a low number of samples (see Figure 4-70), and, as a consequence, the rather high local maximums seen in Figure 4-71 are very unreliable. 198
4.5
4
3.5
3
2.5 10 P
2
1.5
1
0.5
0 -1000 -800 -600 -400 -200 0 Depth [m]
Figure 4-71. P10 from drillhole fracture data (OL-KR1 - OL-KR40) in 10-m horizontal sections.
Distributions of fractures between different fracture classes were calculated (Figure 4-72) and approximately 2/3 of the fractures are filled and 1/5 tight. Over a half of fractures are irregularly shaped and 2/5 semi-rough. According to the mapping of the geological type of fractures, nearly 60% of them belong to curved, wavy or undulating fractures and breakages. The most general types of fractures are single fracture (65%), hair dyke (13%), and single shear (11%). The main lithological environments of the fractures are veined gneiss and diatexitic gneiss, with 60% of all fractures located within these types. 199
classKAIKKI
AB
CD
EF
Figure 4-72. Percentages of fracture types, shapes, roughnesses, geological types, general types, and lithologies.See abbreviations in Table 4-13.
Observations of fracture filling minerals as a percentage of the total amount of fractures are visualized as functions of depth in Figure 4-73 to Figure 4-79. Calcite can be found in approximately 30% of fractures and pyrite in about 25% of fractures, and both increase with depth and are present in approximately 40% of the fractures in the upper 200 metres (Figure 4-73). A similar trend can be seen also with kaolinite (Figure 4-74). The proportion of kaolinite bearing fractures increases from 10% to 30% when 200
comparing the lowest 200 metres awith the near-surface part of the bedrock. Fractures containing illite and chlorite fillings behave opposite to this as their proportion decreases upwards, with illite fractures accounting for 30% to 15% (Figure 4-74 and chlorite fractures for 35% to 15% (Figure 4-75). The percentage of fractures with unidentified clay mineral is about 15% but is increases slightly upwards (Figure 4-75). The more uncommon fracture filling minerals (smectite and montmorillonite, Figure 4-78) do not show as clear a dependency as a function of depth, although pyrrhotite and graphite decreasing slightly (Figure 4-76) and sericite and black pigment increase upwards (Figure 4-77 and Figure 4-79). Relative variations are strong due to low percentages and the small amount of data of uncommon filling minerals.
The pyrite (Figure 4-73), illite, and kaolinite (Figure 4-74 ) trends show clearly the effect of large-scale hydrothermal alteration at the site (see Chapter 4.4). Pyrite and kaolinite are common in the upper part of the bedrock, whereas illite is abundant in deeper parts, as shown in the 3D model of the hydrothermal alteration (see Chapter 4.4). Yet, it should be emphasised that the observed trends in depth dependencies are averages as they are calculated for the whole site volume, and the phenomena which cause them are controlled for example by deformation zones in various directions. Particularly in the case of uncommon filling minerals, the percentages vary strongly, especially in the deepest sections, due to the small number of samples.
50 %
45 %
40 %
35 %
30 %
CC 25 % SK
20 %
15 %
10 %
5 %
0 %
0 0 0 00 50 00 50 00 50 00 50 00 00 50 0 00 10 7 60 550 150 -9 - - -950 - -6 - -5 - -1 0 - -2 -5 0 5 0 - -8 50 - -4 -10 0 - -5 -950 - -900 - -8 -8 -800 - - -750 - -7 -700 -65 0 - - -600 - - -550 -500 - -4 -4 -400 - -350 -350 - -3 -30 -25 0 - -2 -200 - - -150 -1000
Figure 4-73. Percentages of calcite (CC) and pyrite (SK) bearing fractures as a function of depth. 201
40 %
35 %
30 %
25 %
IL 20 % KA
15 %
10 %
5 %
0 %
0 00 50 00 00 0 50 50 00 00 50 50 00 650 500 350 -9 - - -50 - -950 - - - -1 0 - - -50 - 10 50 - -8 00 - -2 -100 -950 - -90 0 - -8 -8 -800 - -750 -750 - -7 -7 0 -650 - -6 -600 - -5 -5 50 -500 - -4 -450 - -4 -400 - -350 - -3 -3 -250 - -200 -200 - -1 -150 -1000
Figure 4-74. Percentages of illite (IL) and kaolinite (KA) bearing fractures as a function of depth.
50 %
45 %
40 %
35 %
30 %
SV 25 % KL
20 %
15 %
10 %
5 %
0 %
0 00 50 00 00 0 50 50 00 00 50 50 00 650 500 350 -9 - - -50 - -950 - - - -1 0 - - -50 - 10 50 - -8 00 - -2 -100 -950 - -90 0 - -8 -8 -800 - -750 -750 - -7 -7 0 -650 - -6 -600 - -5 -5 50 -500 - -4 -450 - -4 -400 - -350 - -3 -3 -250 - -200 -200 - -1 -150 -1000
Figure 4-75. Percentages of clay (SV) and chlorite (KL) bearing fractures as functions of depth. 202
30 %
25 %
20 %
MK 15 % GR
10 %
5 %
0 %
0 0 00 50 00 50 00 50 00 00 0 50 00 50 700 500 450 250 -9 -1 - 1 - -950 - -6 - - 0 - - -5 0 50 - -8 50 - -4 -100 - - -950 - -900 - -8 -8 -80 0 - -750 -750 - - -7 00 -650 - -6 -600 - -5 -55 0 -500 - - -4 -400 - -350 -350 - -3 -3 0 -250 - -2 -200 - -1 -150 - -1000
Figure 4-76. Percentages of pyrrhotite (MK) and graphite (GR) bearing fractures as functions of depth.
10 %
9 %
8 %
7 %
6 %
KV 5 % SR
4 %
3 %
2 %
1 %
0 %
0 00 50 00 0 50 00 00 50 50 00 800 650 450 300 -50 -9 - -950 - -5 - -1 0 - - -5 0 - 1 0 50 - - 00 - -2 -100 - -950 - -900 - -8 -8 -800 - -750 -750 - -7 -70 -650 - -6 -600 - -5 -550 -500 - - -450 - -4 -400 - -350 -350 - - -3 -250 - -200 -20 0 - -1 -1 50 -1000
Figure 4-77. Percentages of quartz (KV) and sericite (SR) bearing fractures as functions of depth. 203
5 %
4 %
3 %
MO SM
2 %
1 %
0 %
0 0 0 0 0 0 0 5 00 50 00 50 5 9 -90 7 6 -60 4 -35 1 -10 - - - 0 0 - - 0 - - 0 0 00 - - -50 - 10 00 - - 50 - - 00 - -450 50 - -200 00 - - -1 -95 -900 - -85 -850 - -800 -800 - -750 -7 -70 -650 - -600 - -550 -550 - -500 -5 -45 -40 -350 - -300 -300 - -250 -2 -2 -15 -10
Figure 4-78. Percentages of montmorillonite (MO) and smectite (SM) bearing fractures as functions of depth.
4 %
3 %
MP 2 % CO
1 %
0 %
0 0 0 0 0 0 0 5 50 50 00 50 1 9 -90 7 -70 5 4 3 -15 - - - 0 - -50 0 0 0 - - 0 - - 0 0 -5 00 - - 50 - -600 00 - - 50 - - 50 - -200 -1 -95 -900 - -850 -850 - -800 -80 -750 - -700 - -650 -6 -6 -550 - -50 -500 - -450 -4 -40 -350 - -300 -300 - -250 -2 -20 -150 - -10 -10
Figure 4-79. Percentages of black pigment (MP) and corrosion (CO) bearing fractures as functions of depth. 204
When considering the thicknesses and coverage4 percentages of the main mineral fillings (carbonate, primary clay (clay), secondary clay (clay2), and sulphides), some anomalies can be detected (Figure 4-80). Where carbonate occurs, the coverage is less than 10% or higher than 90% in 40% of cases (Figure 4-80A). The high amount of 70% - 80% coverage observations is probably caused by visual estimation, in which the 80% coverage refers to 'a bit discontinuous' coverage of a certain filling. About 2/3 of fractures with carbonate has carbonate filling thickness thinner than 0.2 mm (Figure 4-80B). A similar trend can also be seen with clay areas and thicknesses (Figure 4-80C,D), although the proportion of complete coverages of clay-fillings is smaller. There are very few fractures with secondary clays compared to fractures bearing primary clay, but where secondary clay (clay2) occurs, the filling thicknesses are also often larger (Figure 4-80E,F). There are clear population of fractures covered at least 90% by secondary clay but the proportion is smaller than with fractures bearing primary clay. The distributions of sulphide coverages and filling thicknesses correlate with thin and patchy covers (Figure 4-80G,H).
Spatial distributions of the fractures with particular coverages and filling thicknesses of carbonate, primary clay (clay), secondary clay (clay2), and sulphides are presented in Figure 4-81. Large sulphide filling coverages and thicknesses are located mostly near the surface (Figure 4-81G,H); this is compatible with the alteration model although the modelling of sulphidised volume is mainly based on the distribution of pervasive sulphidisation. Thick clay fillings are found in deeper parts (Figure 4-81C,D), which again is compatible with the alteration model and the occurrence of illitised volumes. The zonal distribution of secondary clay fillings (Figure 4-81E,F) can arise from the location of fault zones. The highest carbonate filling coverages and thicknesses are located near the surface of the bedrock (Figure 4-81A,B).
In the fracture database, there is information on the occurrence of 18 single filling minerals. These are calcite (CC), pyrite (SK), kaolinite (KA), chlorite (KL), illite (IL), clay (unidentified) (SV), sericite (SR), graphite (GR), black pigment (MP), quartz (KV), corrosion (CO), pyrrhotite (MK), smectite (SM), montmorillonite (MO), chalcopyrite (CU), dolomite (DO), molybdenite (MH), and nakrite (NA). Binary correlations for pairs of the most common minerals were calculated and the strongest correlations are presented in Figure 4-82. Positive correlation can be found for kaolinite-illite, pyrite- calcite, clay-pyrite and chlorite with calcite, graphite, illite and pyrite. Clay and kaolinite have clear negative correlation. This may be due to the higher frequency of occurrence of kaolinite and easier visual recognition of it. Furthermore, a major component of clay fillings may be actually kaolinite, but due to the composite nature of the clays, its recognition may be difficult.
Most of the kaolinite and illite fillings are likely to be products of the same type of hydrothermal alteration processes and therefore a strong positive correlation between their occurrences is natural. Also other positive correlations may be used as an argument for corresponding or similar genetics of two different filling minerals. As an example, illite is often found on chlorite surfaces of slickensided fractures and therefore illite can be a filling mineral formed in later events of faulting. Positive correlation between calcite and pyrite is also a likely indication of a similar genetic origin and both of them are most likely related to be the last circulating fluids of the hydrothermal system that affected the rock mass.
4 The term coverage refers to the proportion of fracture surface area, which a specific filling covers. 205
area&thickness AB
CD
EF
GH
Figure 4-80. Counts and percentages of carbonate (A and B), primary clay (clay) (C and D), secondary clay (clay2) (E and F), and sulphides (G and H) in classes divided by coverage (%) and filling thickness (mm). 206
3d AB
CD
EF
GH
Figure 4-81. Spatial distribution of carbonate (A and B), primary clay (clay) (C and D), secondary clay (clay2) (E and F), and sulphide (G and H) bearing fractures in classes divided by coverage (%) and filling thickness (mm). 207
correlations AB
CD
EF
GH
Figure 4-82. Correlation of occurrence of mineral pairs kaolinite-illite (A), chlorite- calcite (B), chlorite-graphite (C), chlorite-illite (D), chlorite-pyrite (E), pyrite-calcite (F), clay-pyrite (G), and clay-kaolinite (H). 208
The proportions of fractures with particular filling minerals are listed in Table 4-14. Calcite is present in 35% of fractures and pyrite in 31%. Kaolinite, chlorite and illite all occur in 20-25% of fractures. A group of 17% of fractures bears an (unidentified) clay mineral. Other minerals occur in less than 5% of fractures. Also the percentages of most common filling mineral combinations are presented in Table 4-14 (Observations [%]). Expected probabilities of mineral combinations (probability of the combination [%]) were calculated by using probability to find a particular single mineral in the fracture; the differences between the expected and observed values were also calculated.
Table 4-14. Proportion of fractures with the most common filling minerals and mineral combinations. Expected probabilities of finding a particular combination are calculated from single mineral occurrences. Difference between expected and observed values is calculated in the far-right column. Positive deviations are in red and negative in blue.
Difference between Percentages of occurrence of Probability of the expected and particular filling mineral: Most common filling mineral combination combination [%] Observations [%] observed % Calcite 35.40 No fillings 15.25 24.73 9.47 Pyrite 30.62 Calcite 8.36 6.29 -2.06 Kaolinite 25.00 Kaolinite 5.08 5.18 0.10 Chlorite 22.55 Calcite+Pyrite 3.69 4.52 0.83 Illite 21.16 Illite+Kaolinite 1.36 2.98 1.61 Clay 16.77 Calcite+Chlorite 2.43 2.88 0.45 Sericite 4.47 Pyrite+Kaolinite 2.24 2.54 0.30 Graphite 1.83 Clay 3.07 2.53 -0.54 Black pigment 1.55 Calcite+Pyrite+Chlorite 1.07 2.50 1.42 Quartz 1.41 Illite 4.09 2.37 -1.73 Corrosion 0.70 Pyrite+Clay 1.36 2.17 0.82 Pyrrhotite 0.60 Pyrite 6.73 2.15 -4.58 Smectite 0.38 Chlorite 4.44 1.97 -2.47 Montmorillonite 0.23 Illite+Chlorite 1.19 1.59 0.40 Chalcopyrite 0.02 Calcite+Illite 2.24 1.43 -0.81 Dolomite 0.00 Calcite+Clay 1.68 1.36 -0.32 Molybdenite 0.00 Illite+Kaolinite+Chlorite 0.40 1.11 0.71 Nakrite 0.00 Pyrite+Chlorite 1.96 1.01 -0.95 Pyrite+Clay+Chlorite 0.39 0.69 0.30 Illite+Clay 0.82 0.35 -0.47
Based on the calculations, fractures without any filling minerals are 9.5 percentage units more common than they were expected to be and, therefore, it is logical to have more positive than negative correlations between different fracture minerals. In addition, it is natural that calcite, chlorite, and pyrite have the smallest values in difference between expected and observed percentages as these minerals are present in most of the positively correlating mineral pairs. In general, fractures with two minerals are more common than fractures with single mineral fillings, an observation which is further elaborated on in the following text. 209
Subhorizontal fractures or fractures dipping gently (0 - 40º) to the S or SSE following the strike of the foliation (Figure 4-83) dominate strongly in the fracture data. The fracture distribution is strongly influenced by the common foliation strike. Yet, in addition, two steeply dipping N-S and E-W striking clusters appear in the data.
Figure 4-83. Distribution of fracture directions in OL-KR1 - OL-KR38. Lower hemisphere projection. Fisher contouring. Average foliation direction of the study area is marked in the diagram.
4.6.3.2 Specified volumes
The distribution of fracture properties can also be analysed for limited volumes and data sets. Fractures inside selected deformation zones and their influence zones are presented here as an example of data subsets. In Figure 4-84 - Figure 4-97, the distributions of fracture types, filling thicknesses, etc. are compared between deformation zones and volumes outside the zones.
Figure 4-84 shows that there is smaller proportion of tight fractures and higher amount of filled and slickensided fractures in the influence zones, especially in OL-BFZ053 and OL-BFZ055. Zones OL-BFZ002, OL-BFZ098, and OL-BFZ099 contain slightly more planar fractures when compared to other zones (Figure 4-85). Fracture roughness classes are distributed in OL-BFZ098 similarly to fractures outside the zones whereas OL-BFZ053 and OL-BFZ055 have smoother fractures and in OL-BFZ002 and OL- BFZ099 the number smooth fractures is significantly higher (Figure 4-86). Figure 4-87 and Figure 4-88 show, in terms of the geological type and general type of fracture, that OL-BFZ053 and OL-BFZ055 deviate clearly from data outside the zones and the other zones are closer to the data from outside. Yet, it should be emphasised that the small 210
amount of the data might randomly effect the distributions calculated from fracture data sets of OL-BFZ053 and OL-BFZ055.
Lithological units in the Olkiluoto bedrock are large compared to deformation zones and their influence zones. Hence, the lithology distributions of the zones with a smaller amount of data (OL-BFZ053, OL-BFZ055) do not tell much about the characteristics of the zone or the fractures inside it. In the fracture data of zone OL-BFZ098, the distribution between VGN and DGN is similar to fractures outside of zones (Figure 4-89). Meanwhile, the distribution of these two most common rock types is different in OL-BFZ002 and OL-BFZ099, where the “amount” of DGN is low. Interpretations for more detailed lithological statistics for the zones are too uncertain because of the small size of the data set; e.g. the amounts of "crush" rock are strongly affected by e.g. the drilling technique and orientation between the zone and the drillhole. 211
type
AB
CD
EF
Figure 4-84. Distribution of fracture types (op=open, ti=tight, fi=filled, fisl=filled slickenside, grfi=grain filled, clfi=clay filled) in the cores and influence zones of OL- BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 212
shape
AB
CD
EF
Figure 4-85. Distribution of fracture shapes (curv=curved, ire=irregular, plan= planar) in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL- BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 213
roughness
AB
CD
EF
Figure 4-86. Distribution of fracture roughnesses (roug=rough, smoo=smooth, srou=semi rough) in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 214
geol type
AB
CD
EF
Figure 4-87. Distribution of geological fracture types (c=curved, wavy or undulating fracture wall without sharp edges, f=fracture, totally filled with soft materials, h=slickenside, surface of brittle fault, j=dyke or paleofracture, m=breakage, q=unknown infill, t=planar fracture wall, w=weathered fracture wall) in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 215
general type
AB
CD
EF
Figure 4-88. Distribution of general geological fracture types (fw=fracture zone in penetratively altered/weathered host rock/rock environment, fz=fracture zone or crushed rock. Host rock/parent rock is not weathered or altered, hd=hair dyke, kt=break, pf=palaeo fracture/ fracture filled with a hard, dense mineral infill, sf=single fracture, ss=single/individual fault/shear, sz=fault zone; zone of multiple subparallel faults of unknown age and origin) in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 216
lithology
AB
CD
EF
Figure 4-89. Distribution of lithology of the fracture environment (CRUSH=crushed rock, DGN=diatexitic gneiss, GRF=graphite seam, MDB=diabase, MFG=mafic gneiss, MGN=mica gneiss, PGR=pegmatitic granite, QGN=quartz gneiss, SGN=stromatic gneiss, TGG=tonalitic granodioritic granitic gneiss, VGN=veined gneiss) in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 217
Major fracture mineral (carbonate, clay, secondary clay, sulphide) coverage and filling thickness distributions are presented for zones OL-BFZ002, OL-BFZ053, OL-BFZ055, OL-BFZ098, OL-BFZ099, and the volumes outside these zones (Figure 4-90 - Figure 4-97). The main findings from these figures are the slightly lower amounts of sulphides and carbonates and higher amounts of clay minerals in the fracture sets belonging to the fault zones and their influence zones.
carb area
AB
CD
EF
Figure 4-90. Distribution of carbonate filling coverage in carbonate bearing fractures in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 218
carb thickness
AB
CD
EF
Figure 4-91. Distribution of carbonate filling thickness in carbonate bearing fractures in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 219
clay area
AB
CD
EF
Figure 4-92. Distribution of clay filling coverage in clay bearing fractures in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 220
clay thickness
AB
CD
EF
Figure 4-93. Distribution of clay filling thickness in clay bearing fractures in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 221
NO OBSERVATIONS clay2 area
AB
CD
EF
Figure 4-94. Distribution of secondary clay filling coverage in secondary clay bearing fractures in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL- BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 222
NO OBSERVATIONSclay2 thickness
AB
CD
EF
Figure 4-95. Distribution of secondary clay filling thickness in secondary clay bearing fractures in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL- BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 223
sulph area
AB
CD
EF
Figure 4-96. Distribution of sulphide filling coverage in sulphide bearing fractures in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 224
sulph thickness
AB
CD
EF
Figure 4-97. Distribution of sulphide filling thickness in sulphide bearing fractures in the cores and influence zones of OL-BFZ002 (A), OL-BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E), and the volume outside these zones (F). 225
Percentages of fractures with particular filling mineral and the most common filling mineral combinations were calculated for the cores and influence zones of brittle fault zones OL-BFZ002, OL-BFZ053, OL-BFZ055, OL-BFZ098, OL-BFZ099, and for the volume outside of these zones; the results are presented in Table 4-15. Differences between the zones and rock volume outside the zones in percentages of occurrence of particular filling minerals were calculated. Zone-specific fracture properties can be detected from the deviations of filling mineral percentages. 226
Table 4-15. Proportion of fractures with the most common filling minerals and mineral combinations. In the cases of single minerals, zone-specific positive and negative deviations are in red and blue, respectively. In the proportions of mineral combinations, twelve of the most common in every case are in grey.
Excl. major deformation All fractures zones and from OL-KR1 - influence OL-KR40 zones OL-BFZ002 OL-BFZ053 OL-BFZ055 OL-BFZ098 OL-BFZ099
Percentages of occurrence of particular filling mineral: Calcite 35.40 35.0734.57 36.25 28.75 39.53 32.19 Pyrite 30.62 31.48 17.50 29.57 18.85 37.89 17.59 Kaolinite 25.00 26.10 18.18 10.17 8.95 18.06 28.81 Chlorite 22.55 21.28 34.10 32.75 22.68 21.12 33.48 Illite 21.16 19.97 33.33 20.19 21.73 17.89 40.64 Clay 16.77 17.25 10.29 16.53 20.13 17.46 10.30 Sericite 4.47 4.504.82 4.45 2.56 5.63 3.30 Graphite 1.83 1.70 3.50 3.50 0.00 1.16 3.62 Black pigment 1.55 1.57 0.73 0.95 3.51 2.11 0.85 Quartz 1.41 1.45 0.81 0.16 0.00 2.19 0.80 Corrosion 0.70 0.68 1.24 0.32 0.00 0.77 1.45 Pyrrhotite 0.60 0.650.51 0.00 0.00 0.47 0.08 Smectite 0.38 0.33 0.00 0.00 0.00 2.11 0.00 Montmorillonite 0.23 0.26 0.00 0.00 0.00 0.09 0.12 Chalcopyrite 0.02 0.010.00 0.00 0.00 0.17 0.00 Dolomite 0.00 0.00 0.04 0.00 0.00 0.00 0.00 Molybdenite 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Nakrite 0.00 0.01 0.00 0.00 0.00 0.00 0.00
Percentages of filling mineral combinations: No fillings 24.73 24.38 26.63 36.41 41.85 24.52 25.11 Calcite 6.29 6.28 7.26 3.97 2.24 8.17 3.94 Kaolinite 5.18 5.72 1.71 0.79 0.96 2.80 3.30 Calcite+Pyrite 4.52 4.68 2.56 4.29 2.24 5.81 1.65 Illite+Kaolinite 2.98 2.90 4.27 0.79 2.86 1.68 7.08 Calcite+Chlorite 2.88 2.63 5.51 3.02 7.03 2.32 4.06 Pyrite+Kaolinite 2.54 2.79 0.60 0.64 0.32 2.37 0.80 Clay 2.53 2.70 2.13 1.11 2.88 1.68 0.85 Calcite+Pyrite+Chlorite 2.50 2.33 2.99 4.29 4.15 3.10 2.62 Illite 2.37 2.18 5.04 1.27 5.75 1.25 5.03 Pyrite+Clay 2.17 2.29 0.98 1.43 3.83 2.41 0.68 Pyrite 2.15 2.28 0.64 1.27 0.00 3.05 0.68 Chlorite 1.97 1.93 2.56 2.38 0.64 1.76 2.29 Illite+Chlorite 1.59 1.30 5.55 3.18 0.96 0.95 5.07 Calcite+Illite 1.43 1.27 2.22 2.70 1.28 1.46 3.10 Calcite+Clay 1.36 1.321.41 1.43 1.60 1.76 1.17 Illite+Kaolinite+Chlorite 1.11 1.00 2.60 0.32 0.00 0.47 3.94 Pyrite+Chlorite 1.01 0.95 1.24 1.75 0.00 1.94 0.68 Pyrite+Clay+Chlorite 0.69 0.68 0.26 1.75 2.24 0.95 0.32 Illite+Clay 0.35 0.360.09 0.64 3.51 0.17 0.16 Others 29.64 30.0223.76 26.57 15.66 31.38 27.45 Total number 45899 38556 2343 629 313 2325 2485 Total number of different filling combinations is 563 227
It can be noted from Table 4-15 and Figure 4-98 that fractures with no filling minerals and fractures with several minerals are more common in the fault zones; only fractures bearing one single mineral are more common outside the zones. The probable reason for the large amount of fractures without fillings and fractures with several minerals inside the zones may be related to the fracturing process and formation of gouge material during the faulting and to the preference of fluids to circulate within the zones; the high amount of fractures without mineral fillings may be due to the formation of isolated fractures during the faulting, which did not act as potential fluid pathways.
35,00
30,00 28,93 28,97
26,53
24,38 25,00
22,25
20,00 18,55 18,18 17,38 %
15,00
10,00
5,58 5,80 5,00
1,14 1,31 0,34 0,65 0,00 0,01 0,00 0,00 0,00 0,00 0,00 0123456789 number of filling minerals
outside inside
Figure 4-98. Percentages of fractures with different number of filling minerals. Minerals are calculated inside the influence zones of OL-BFZ002, OL-BFZ053, OL- BFZ055, OL-BFZ098, OL-BFZ099 (in green), and outside of them (in yellow).
The influence of a deformation zone can be found rather far from the core of the zone, although most of the fractures inside influence zones are obviously background fracturing, due to large influence zones. This may ‘shield’ the deformation zone’s specific characteristics in data subsets from influence zones and can also be seen when the distributions of fracture directions are analysed. Some characteristic distribution can be seen in the orientations but it can be explained by quite small datasets. Fracture directions are presented in Figure 4-99. For most fault zones, weak clusters of N-S and 228
E-W trending fractures can be identified, although a main cluster concordant to the foliation direction (subhorizontal fractures dipping to the SE) is found in every subset. Zones OL-BFZ053 and OL-BFZ055 have the smallest amount of data and show slightly different features. Subhorizontal clustering is not as obvious for them and a set of vertical NE-SW trending fractures is also present.
A B
C D
E F
Figure 4-99. Directions of fractures inside the influence zones of OL-BFZ002 (A), OL- BFZ053 (B), OL-BFZ055 (C), OL-BFZ098 (D), OL-BFZ099 (E) and outside them (F). Lower hemisphere projection. Fisher contouring. 229
4.7 Integrated assessment of different 3D submodels and disciplines
To achieve a consistent view of the properties of the bedrock at Olkiluoto, in the following text selected submodels and disciplines are briefly approached in an integrated manner.
4.7.1 Lithology and brittle deformation model
Several site-scale fault zones have been identified in the current model and the question is do we see any evidence of block faulting? The low-angle site-scale zones are thrust faults and as a consequence, if significant movements have occurred within these zones, as should have due to their sizes, it should be possible to distinguish them as the offsets of older structures. In Figure 4-100, the modelled pegmatitic granite units are plotted with the site-scale zones and from the figure some indications of block faulting may be inferred: - faults OL-BFZ098 and OL-BFZ080 seem to crosscut the existing granite units and, in addition, it can be hypothesised whether the bending observable on the granite unit located on the hanging wall of the faults is due to the faulting. The possible vergence of the bending would indicate thrusting, compatible with the kinematics of the faults. Similar bending of the foliation is associated with the thrust faults observed in the ONKALO tunnel.
OL-BFZ099 and OL-BFZ002 do not seem to offset any pegmatitic granite units although one granite units does end at fault OL-BFZ002 in the right-hand part of Figure 4-100. In addition, fault zone OL-BFZ099 seems to have exploited the existing lithological boundaries and ductile fabric as it closely follows the existing boundaries. This observation is again compatible with the observations from the ONKALO tunnel as some of the intersected faults clearly follow the ductile fabric, reflecting local variations in the orientations of the thrust faults. 230
Figure 4-100. Faulting in respect to pegmatitic granite units. View is towards W and Easting = 1525 900.
4.7.2 Alteration and brittle deformation model
Different alteration types and volumes are compared to the modelled site-scale fault zones in Figure 4-101 - Figure 4-103. Illitisation has a clear correspondence in zones OL-BFZ002, OL-BFZ099, OL-BFZ098 and OL-BFZ080 (Figure 4-101), and as the illitisation is interpreted to have originated during the extensional period and the intrusion of rapakivi granites at approximately 1580-1550 Ma, the extension and reactivation of the existing thrust faults in that period may have produced dilatational gaps, increasing the permeability of the zones, and prominent pathways within the faults, exploited by the hydrothermal fluids. Consequently, although the illitised volumes refer to the occurrence of pervasive alteration, it is closely linked to the existing fault and fracture network. The “bending” of the upper volume of illitisation towards OL-BFZ099 may indicate a link to OL-BFZ098 and OL-BFZ080.
Kaolinisation and sulphidisation and site-scale faults are shown in Figure 4-102 and Figure 4-103, respectively. In contrast to illitisation, no direct correlation between the alteration and site-scale faulting can be observed and especially the kaolinitised volume has a deviating trend from the faults and the ductile fabric, which may indicate pathways more complicated than currently modelled. These pathways may relate to the general fracture network or diffusion properties of the intact rock at the time of the hydrothermal alteration. 231
Figure 4-101. Illitisation in respect to the main faults of the site area. Illitisation is shown as green volumes and faults as brown surfaces.
Figure 4-102. Kaolinisation in respect to the main faults of the site area. Kaolinisation is shown as yellow volumes and faults as brown surfaces. 232
Figure 4-103. Sulphidisation in respect to the main faults of the site area. Sulphidisation is shown as blue volumes and faults as brown surfaces.
4.7.3 GPS measurements and brittle deformation zones
GPS measurements at Olkiluoto have been ongoing since 1995, and currently there are 10 operational stations at Olkiluoto, which are measured twice each year. The latest results of the measurements and corresponding calculations have been reported in Ahola et al. (2007), which showed that statistically significant rates of horizontal velocities occur at Olkiluoto, although the rates are very small. The maximum velocity with respect to station OL-GPS1 is in station OL-GPS4 (east component velocity of 0.23 mm ± 0.023 mm/y, Table 4-16, Figure 4-104). Other significant rates in respect to OL- GPS1 are in stations OL-GPS2, OL-GPS7, OL-GPS8 and OL-GPS9. When the rate of movements of the GPS stations are compared to the interpreted linked lineament map (Figure 4-105, Korhonen et al. 2005), two linked lineaments, LINKED0255 and LINKED0145, seem to be closely associated with the observed movements; lineament LINKED0145 traverses approximately E-W, with the stations OL-GPS8 and OL-GPS4 located on the northern side of the lineament and OL-GPS7 and OL-GPS9 on the southern side. Lineament LINKED0255, on the other hand, traverses approximately SWW-NEE, station OL-GPS8 located on the northern side of the lineament and OL-GPS8, 7 and 9 on the southern side, although OL-GPS9 is close to the actual location of the lineament. Lineament LINKED0255 is also considered as the surface location of the site-scale fault zone OL-BFZ099 (See descriptions in the preceding sections). Lineament LINKED0145 on the other hand is not associated with any brittle deformation zone. Yet, further analysis of the GPS-data is needed in order to characterise possible deformations and their relation to the properties of the existing fault zones and the current stress regime at Olkiluoto. 233
Table 4-16. The horizontal velocities of the GPS stations in mm/a with respect to the permanent GPS station (GPS1) at Olkiluoto. The velocities and the estimated errors are obtained from least squares solutions of 22 measurements performed in 1995-2006. The stations with statistically significant velocities are highlighted. From Ahola et al. (2007).
North component East component Station Velocity [mm/a] St.dev. [mm/a] Velocity [mm/a] St.dev. [mm/a]
GPS1 0 0 0 0 GPS2 0.049 0.029 -0.174 0.037 GPS3 0.044 0.047 -0.08 0.036 GPS4 0.108 0.042 -0.228 0.023 GPS5 -0.017 0.056 -0.018 0.037 GPS6 0.002 0.039 -0.088 0.034 GPS7 0.108 0.019 -0.087 0.025 GPS8 0.075 0.023 -0.217 0.037 GPS9 0.113 0.019 -0.098 0.028 RMS: r0.034 r0.031
Figure 4-104. Horizontal velocities of the GPS stations at Olkiluoto relative to the permanent GPS station (1). The length of the arrows indicates rate of the movement and the size of the circles the standard deviation. From Ahola et al. (2007). 234
Figure 4-105. The locations of the GPS stations at Olkiluoto with respect to interpreted linked lineaments with low uncertainty (black lines, from Korhonen et al. 2005).
4.7.4 Microseismicity and brittle deformation zones
Posiva Oy has operated a local microseismic network at Olkiluoto since February 2002; currently there are 11 stations on the Island, and 10 of them are located within the Site Area (Figure 4-106). The microseismic monitoring works on continuous basis and the latest results have been reported in Saari & Lakio (2007). Since the start of the monitoring in 2002, five excavation-induced earthquakes have been observed, and the details of the events are given in Table 4-17.
As stated in Saari & Lakio, two of the induced events are linked to known fault zones (as modelled in Paulamäki et al. 2006) and two to a long fracture mapped form the ONKALO tunnel. One observation is located inside the tunnel spiral, at some distance from the long fracture associated with the earlier two observations. The event that occurred on 14.9.2006 is associated with a vertical fault zone OL-BFZ043, striking approximately NW-SE. The fault also intersects the ONKALO tunnel, approximately at chainage 1360. The event was located approximately 70 metres from the ONKALO access tunnel (Figure 4-107A). The 27.11.2006 event is associated with fault zone OL- BF034, located approximately at chainage 1500 metres of the ONKALO tunnel Figure 4-107B); the event was located in the tunnel wall. The other three events occurred close 235
to each other, both spatially and temporally (26.9, 27.9 and 29.9.2005) and two of them were associated with the activation of a long fracture, located approximately at tunnel chainage 740 m (Figure 4-107C,D). The event that occurred on 26.9.2005 (Blue sphere in Figure 4-107C and D), was not associated with any know structure. The slip amounts of the events range from 3 to 72 µm (Table 4-17).
As the microseismic monitoring works on continuous basis, each encountered event will be assessed geologically and incorporated into the model if considered valid (i.e. whether the events are associated with a zone or a fracture).
Figure 4-106. The locations of the microseismic stations at the Site Area at Olkiluoto 236
Table 4-17. Excavation induced earthquakes, in 2005 and 2006. Loc. Err = location error, Mag Loc = local magnitude, r = estimated radius of the seismic source, peak slip = dislocation across the fault and No of Acc = number of recordings used in analysis. From Saari & Lakio (2007).
No Date Origin North East Depth Loc. Mag Seismic rPeak slip No. Time (m) (m) (m) Err. Loc Mom.(µm) of (UTC) (m) (log10) (m) Acc. 1 26.9.2005 20:47:13.4 6792024.0 1526062.6 -100.6 0.0 -0.6 2.4 14.4 3 3 2 27.9.2005 14:23:02.7 6792015.0 1526095.8 -66.8 2.6 0.1 3.7 9.4 72 8 3 29.9.2005 08:24:02.4 6792008.5 1526088.3 -65.5 2.1 -0.4 2.9 6.0 38 6 4 14.9.2006 02:48:48.3 6792377.5 1525855.4 -173.1 19.9 -0.6 2.2 10.9 14 4 5 27.11.2006 21:29:03.3 6792206.0 1526011.8 -144.9 3.7 -0.9 8.5 8.0 4 3 237
A B
C D
Figure 4-107. (A) Fault plane of the earthquake that occurred on 14.9.2006. View along the nearly vertical the structure OL-BFZ043 (in blue). Insert - closer view from west. Slip direction of the hanging wall is shown by black line pointing from the hypocentre to the edge of the fault; (B) Fault plane of the earthquake that occurred on 27.11.2006 and the excavation blast before that. View along the fault plane. In this view, the slip vector (yellow bar) on the plane cannot be seen as clearly as the plane. Structure OL-BFZ034 is presented in blue. The arrows in the middle show the directions: West (green), South (red) and down (blue). The view is from NW; (C) Fault planes of the earthquakes that occurred on 27. and 29.9.2005. Long fracture R28 (Geological mapping data) on the tunnel wall is presented by a blue line. View from SE perpendicular to the tunnel wall. The bottom line and profile in the corves of the ONKALO are presented. Slip direction of the hanging wall is shown by a black line pointing from the hypocentre; (D) is the top view of (C). From Saari & Lakio 2007. 238 239
5 CONFIDENCE ASSESSMENT
This chapter assesses the overall consistency and confidence in the Geological Site Model Version 1.0 and focuses on discussing the main issues of importance that are deemed to require further attention.
5.1 Data resolution5
In general, the main data related sources of uncertainty in geological modelling are a low number of drillholes, uneven distribution of the drillholes, long distances between the drillholes as well as biases in drillhole orientation. At Olkiluoto, the ONKALO area is well covered with drillholes and therefore the confidence of the model is also higher in the area; nevertheless, in the modelled Site area, there are still a few "white areas", where the drillhole density is quite low and, similarly, the confidence of the model is also low In addition, in places where there are no drillholes, deterministic modelling is difficult due to lack of proper data and, as a consequence, these areas are likely to be underrepresented by geological features in the model. Another cause of uncertainty is the quite uniform drilling orientation that causes bias, as it masks the occurrence of possible N-S trending features, although, with the current drillhole density, possible “masked features” are likely to be only of local importance. An assessment of the confidence of the model, based on the distribution of surface-based drillholes, outcrops and investigation trenches is shown in Figure 5-1, where the high-confidence area is represented by a cluster of circles (light-blue), each depicting a 200 m “radius of confidence” around each drillhole. From the figure it is obvious that the main areas of lower confidence are located within the NE- and SW-parts of the Site Area and the NE- part is also characterised by the lack of natural outcrops. Figure 5-1 depicts the surface conditions and cannot be directly applied to 3D; the effect in 3D can be demonstrated by Figure 5-2 which is based on the study of Kuusisto et al. (2007) who analysed the variance of lithology within the Site Volume by the division of the volume into cells of the size 200m x 200m x 200m. The size of each “sphere” in Figure 5-2 depicts the amount of geological data in the corresponding cell (i.e. how many drillhole metres intersect the specific cell), and from the figure it is obvious that the amount of data is lowest in the NE-, S- and SE-parts of the Site Volume. This is affected by the W/NW dip direction of the drillholes. The top view projection is shown in Figure 5-3.
The confidence assessment given in the above sections refers only to geological data, although extensive campaigns of geophysical measurements have been conducted
5 This section focuses purely on the strict evaluation of available data and it’s resolution within the Site Model Volume, but it should be emphasised these are not the only factors determining the confidence of a model; more important is to emphasise that in any geological modelling, the main role is in the understanding of the key elements which control the properties of the bedrock and which can be then further applied in the extrapolation and interpolation of the existing data into areas of lower data resolution, without any major loss of confidence. At Olkiluoto, for example, a factor which actually can be considered to increase the confidence of the model is the existence of well-known and constrained pervasive anisotropy, which can be used as a guide during the modelling of lithological units. Consequently, the knowledge of key controlling factors and geological understanding developed during many years of investigations can be used to complement lower data resolution, without a loss of confidence. 240
during the site investigations. Therefore, although in certain parts of the Site Volume the confidence may be considered low from the perspective of geological data, the confidence may be increased by the application of geophysical data. Yet, as the measurements are mainly based on borehole geophysics or are more focused on the western part of the Site Area (see Appendix II), the overall confidence in the NE-, S- and SE-parts may be considered as low to medium.
Figure 5-1. The location of the drillholes 1-43 (red triangles), investigation trenches (black lines) and observation points (black crosses) and the area of higher confidence (presented as a cluster of light-blue circles). The area adjoining the high-confidence area within the Site Area (black rectangle) depicts an area with lower data density and thus the confidence of the model is lower in this region. Note that the figure refers to the conditions at the surface. 241
Figure 5-2. Variances of rock types. The size of cells where the variance is computed is 200m x 200m x 200m. View towards 315°/ -45°. The sizes of the spheres correspond to the amount of data within each cell. 242
Figure 5-3. Variances of rock types, top view projection from the previous picture. The size of the cells where the variance is computed is 200m x 200m x 200m. The sizes of the spheres correspond to the amount of data within each cell.
5.2 Main uncertainties
The uncertainties for each submodel is treated in the corresponding sections in the preceding text; in the following sections, the uncertainties considered to have medium to high impact on the model are further elaborated on.
5.2.1 Lithological model
The main uncertainty in the lithological model is related to the extent and geometry of the lithological units at depth and this uncertainty is more pronounced in the low- confidence area due to supporting data. Unknown lithological units may occur, although the probability in the Site Area is considered low, especially for site-scale lithological units, due to quite good data resolution In addition, as the lithological model is based on the ductile deformation model, any uncertainty in the ductile model directly affects the lithological model. Based on the current observations and the data acquired from the ONKALO tunnel and drillholes, the confidence of the lithological model is considered high, although for local-scale lithological units the uncertainties are higher than for site- scale units. 243
5.2.2 Ductile deformation model
The main uncertainty of the ductile deformation model is purely conceptual and relates to the understanding of the various deformation phases interpreted from the site. The uncertainty reflects the complexity of the ductile deformation and the associated small- scale heterogeneities of the bedrock. Yet, this uncertainty is considered to have a quite low impact on the geological model as the current structural model seems to explain the majority of the observed features and this is also reflected in the confidence of lithological model, which applies the ductile model directly in the modelling approach. It is also emphasised that we do not need to know all of the deformation history, as long as the confidence in the understanding is considered good enough. This is of course directly related to the resolution of the model and to the question: What is the level of detail we can predict with good confidence (and what is the level needed)? This topic will be further elaborated on in the ongoing prediction-outcome studies and will be directly influenced by the needs of the end-users of the model.
5.2.3 Alteration model
The current alteration model is based on the identification of volumes of the highest degree of pervasive alteration and this causes uncertainties in the location and extent of the alteration – there may be sections within the modelled alteration volumes with no alteration. Similarly, in addition to the pervasive alteration, by the incorporation of fracture-controlled alteration into the modelled volumes, the extent of alteration may increase significantly, although it is realised that the pervasive alteration is a property of “intact” rock whereas fracture-controlled alteration is a property of fracturing and can be treated as such in the handling of fracture data. Another main source of uncertainty relates to the intensity of the alteration, i.e. how much variation is there on the intensity (or degree) of alteration? Another question is exactly what impacts this possible variability would have on the current model and on the properties of the rock.
5.2.4 Brittle deformation model
The confidence for the site-scale zones is considered high (i.e. confidence for their existence), but uncertainties related to their size and locations exist and this is caused by limited data resolution and the natural variability of the zones, reflected by markedly different characteristics in various intersections (tunnel, drillholes, trenches). This uncertainty can be approached by the application of geophysical methods and direct observations from the tunnel – such as how much variability one zone may have on different intersections?
Unknown brittle deformation zones may exist but in the Site Volume these are likely to be only of local importance. The predictive capability of the current model will be tested through prediction-outcome studies, which may answer to the question: How many deformation zones, which were not incorporated in the current model, were intersected by tunnel? What is the size of these features?
The size of the deformation zones is an important uncertainty – currently a majority of the zones are modelled on the basis of restrictive criteria, for example, due to the occurrence of bounding drillholes with no supportive data for the continuation of the modelled zones. Again, prediction-outcome studies may partly answer this question, but 244
further elaboration is needed on the applicability of fault scaling laws, which correlate fault widths and displacements to their sizes.
5.3 Main issues
As was stated in the preceding section, the modelling results contain uncertainties related to the accuracy of size, location and characteristic parameters of the modelled units. The modelling of geological features is basically an iterative, dynamic process, where continuous processing of the data yields new ideas and concepts, which may be incorporated into the updated versions of the geological model. This version of the model is an update of the version 0 (Paulamäki et al. 2006), but will be continuously refined and updated as new data is acquired, especially from the ONKALO access tunnel.
The main issues that are judged to require further attention in the next versions of the Geological Site Model are:
x Although the understanding of the lithological and ductile evolution is considered to have a good confidence, further development is required, especially if the resolution is to be increased to small-scale phenomenon. This development is of course focused on the end-users of the model and this topic will be discussed during forthcoming model integrations. The understanding of the brittle evolution is in its early stages and will require further development; the mechanisms of formation of the site-scale zones have been analysed but the approach will be extended to cover second-order and small-scale structures associated with the main zones, i.e. what is the relation between local-scale zones to site-scale zones?
x The rock mechanical characteristics of the hydrothermally altered and weathered zones need to be investigated in more detail, since these are likely to have important implications for ONKALO construction. Possible correspondences between the effects of alteration in different lithologies, and the products of ductile deformation and brittle deformation need to be evaluated in more detail in the course of future modellings.
x The specific internal characteristics of modelled brittle fault zones need to be presented, although it must be recognized that the characteristics of faults are typically highly variable and discontinuous and therefore the descriptions of particular intersections are not necessarily applicable to the fault as a whole. A highly crushed intersection of a fault at one intersection may transform into a single shear fracture at another intersection (adding to the heterogeneity of the rock mass and limitations of the modelling work). This issue also concerns the applicability of scaling laws, i.e. what is the correlation between fault width/displacement to fault size?
x The fault analysis given in this report will be continued and refined as new data from new drillholes, tunnel and instrumental analysis (e.g. age determinations) 245
is acquired. In addition, the analysis will be extended to the close-by areas surrounding the Olkiluoto Island for correlation of fault data at a larger scale. x The analysis on influence zones will be further developed for the next versions of the geological model. At this point, the rules applied in the definition of the width of the influence zone are considered conservative, and as a consequence, in the future, the rules are expected to become more precise, together with the sizes of the influence zones. Furthermore, the applicability of the rules for local-scale fault zones in the future versions will be assessed. x The resolution of the stochastic approach for characterising fracturing will be increased in bedrock volumes where the methods of deterministic modelling are not applicable. x In the present report, for practical reasons, the Site Model has been divided into thematic submodels, but additional integration of these is needed in order to increase the internal confidence of the model, and the “rock domain” approach used for example by SKB will be considered in the future versions. x The SITE model will be updated every 2-3 years, as new data is acquired from drillings, trenches and the ONKALO access tunnel. The update frequency will be coordinated through the Olkiluoto Modelling Task Force (OMTF). Prior to the update, a decision on the data freeze needs to be made in order to keep a balance between the decided deadlines and the acquisition of new data. x In the next modelling period, an important process is the continuous assessment of hydrological, hydrogeochemical and rock mechanical data from the perspective of geological data - the results will be then used as an important tool in the development of the geological model and building of separate integrated models (hydrogeological model, rock mechanics model and hydrogeochemical model). x All the above-mentioned issues will be addressed in the course of future modelling activities, with the acquisition of new data and the development of concepts based on the geological history and the style and type of deformation. 246 247
6 SUMMARY
The geological model of the Olkiluoto Site Area is composed of five submodels: the lithological model, the ductile deformation model, the brittle deformation model, the alteration model and the fracture system model. The lithological model gives the properties of definite rock units that can be defined on the basis the migmatite structures, textures and modal compositions. The ductile deformation model describes and models the products of polyphase ductile deformation, which makes it possible to define the dimensions and geometrical properties of individual lithological units determined in the lithological model. The brittle deformation model describes the products of multiple phases of brittle deformationand the fracture system model describes fracture properties statistically, although currently this part of the report focuses on a statistical analysis of selected fracture data - a proper fracture system model will be presented in the near future.
The rocks of Olkiluoto can be divided into two major classes: 1) high-grade metamorphic rocks including various migmatitic gneisses, tonalitic-granodioritic- granitic gneisses, mica gneisses, quartz gneisses, and mafic gneisses, and 2) igneous rocks including pegmatitic granites and diabase dykes. The migmatitic gneisses can be further divided into three subgroups in terms of the type of migmatite structure: veined gneisses, stromatic gneisses and diatexitic gneisses, the last mentioned representing distinct end members in a transition system of gneisses and migmatitic gneisses. The change from rather homogeneous gneisses to migmatitic gneiss variants and between the migmatitic gneisses takes place gradually, so that it is not possible to define any natural borders between the end members. Thus, an artificial border between the homogeneous gneisses and migmatitic gneisses has been set at 10% or 20% of the leucosome. The veined gneisses account for 43% of the volume of the Olkiluoto site area, the stromatic gneisses for 0.4% and the diatexitic gneisses for 21%. The granite pegmatites make up 20% of the bedrock, the tonalitic-granodioritic-granitic gneisses 8%, mica gneisses 7% and the mafic gneisses 1%.
Based on whole rock chemical analyses, the supracrustal rocks can be divided into four distinct series: the T series, S series, P series and mafic or ultramafic, probably volcanogenic gneisses. In addition, pegmatitic granites and diabases form groups of their own. Rocks of the T, S and P series are estimated to make up 42-46%, 7-12% and 26-28%, respectively, of the volume of the central part of the island of Olkiluoto and the various pegmatitic granites about 20%. The T series includes mica gneisses and migmatitic gneisses with less than 60% SiO2 and quartz gneisses with more than 75% SiO2, representing clay mineral-rich pelitic materials and greywacke-type impure sandstones, respectively. The members of the S series, characterised by their high calcium content, have originated from calcareous sedimentary materials. The P series, which is mainly composed of tonalitic-granodioritic-granitic gneisses, is characterised by its high P2O5 concentrations that exceed 0.3%. A comparison of the chemical compositions of the different series indicates that the origin of the protolith for the P- type gneisses most likely include mixing of the volcanic and turbiditic components and subsequent physical and chemical enrichment processes. 248
On the basis of refolding and crosscutting relationships, the supracrustal rocks have been subjected to polyphased ductile deformation, made up of five stages. The main deformation phase D2 is characterised by intense thrust related folding and abundant leucosome production. Shear related structures have been observed as the most important D2 elements in certain zones. In deformation phase D3 the earlier structures were zonally refolded or rotated. Zones dominated by ductile D3 shears and folds were formed, and often, e.g., the S2 foliation was reoriented parallel to the F3 axial plane (S3). Simultaneously with D3 deformation a new granitic leucosome intruded parallel to the F3 axial planes and major E-W striking ductile shear zones were formed. Subsequently the D3 and earlier elements were again re-deformed in the deformation phase D4, which produced more open F4 folds with axial planes trending ca. NNE –SSW and shear zones parallel to the axial planes. Due to D4 deformation, the S2/3 composite structures are zonally reoriented towards the trend of the F4 axial plane. Open fold structures with steep axial planes striking to the SE and fold axes often plunging to the same direction have been interpreted to be products of the D5 stage. These fold structures can be detected as small flexures or outcrop-scale undulation of younger planar elements.
In 3D modelling of the lithological units, an assumption has been made, on the basis of measurements in outcrops, investigation trenches and drill cores, that the pervasive, composite foliation produced as a result a polyphase ductile deformation has a rather constant attitude in the Site Area. Consequently, the strike and dip of the foliation has been used as a guide, through which the lithologies have been correlated between the drillholes and from the surface to the drillholes. The lithological modelling mainly comprises modelling of the tonalitic-granodioritic-granitic gneisses and the pegmatitic granites. In addition the contact zone of the diatexitic gneisses and veined gneisses has been modelled as well as the narrow diabase dykes. The veined gneisses form the main volume of the model area. The tonalitic-granodioritic-granitic gneiss and pegmatitic granite intersections in drillholes more than ca. 10 metres in thickness have been distinguished as separate units. Furthermore, adjacent pegmatitic granite sections less than 10 m in length, separated by short sections of homogeneous or migmatitic gneisses were combined into larger units with the assumption that the gneisses represent inclusions within the pegmatitic granite. The 3D lithological model of the Olkiluoto Site Area currently contains 19 mica gneiss units, 32 units of tonalitic-granodioritic-granitic gneisses, 62 units of pegmatitic granite, seven diabase dykes and two diatexitic gneiss units.
The bedrock in the Olkiluoto site has been subjected to extensive hydrothermal alteration, linked to the phases of magmatic activity. The alteration has taken place at reasonably low temperature conditions, the estimated temperature interval being from slightly over 300oC to less than 100oC. Typically, high permeability zones were created and these zones appear to have repeatedly acted as pathways for the periodic circulation of thermal fluids. Two types of mode of occurrence can be observed in the hydrothermal alteration processes: 1) pervasive (dissemination) alteration and 2) fracture-controlled (veinlet) alteration. Illitisation, kaolinisation and sulphidisation are the most prominent alteration events at the site model area. Sulphides are located in the uppermost part of the model volume following roughly the lithological trend (slightly dipping to the SE). Kaolinite is also located in the uppermost part, but the orientation is opposite to the main lithological trend (slightly dipping to the N). The third main alteration event, illitisation, consists of two distinct volumes, which lie one on the other 249
and converge in the northwest, and are spatially associated with site-scale thrust faults. Calcite occurs as fracture infillings and as stockwork vein sets in the same bedrock volume as the other three hydrothermal alteration zones and at least part of that is understood to present carbonatisation, which, however, has not affected the rock itself. The lower surfaces for the modelled alteration volumes given in this report are to be taken as the cut-out, which is based on the present drillhole information, and other available geo-analytical records received so far.
The bedrock in the hydrothermally altered volumes has been affected by strong chemical and physical modifications and the most essential compounds, which may have mobilised in these processes, are the oxides of alkaline earths, alkalies, SiO2, Al2O3, FeO, P2O5, U2O, ThO2, CO2, S, Cl and F. The contents of these compounds in unaltered and altered bedrock volumes and their mutual proportions are potential markers of the grade of alteration. The increased concentrations of CO2 and the compounds of sulphur are anticipated to have had an influence on the acidity of ground and matrix water conditions and subsequently to the solution- dissolution behaviour of some of the elements at the zones.
The fault zones at Olkiluoto are mainly SE-dipping thrust faults formed during contraction in ductile, semi-ductile to semi-brittle regime during the latest stages of the Fennian orogeny, at approximately 1800 Ma ago and were reactivated at several deformation phases, as indicated by fault-slip data and K-Ar age determinations. In addition, NE-SW striking strike-slip faults of the approximate age of 1560-1270 Ma in age are also common. Fault zone intersections from drillholes, the ONKALO access tunnel and outcrops have been correlated by the application of slickensides orientations, mise-à-la-masse-measurements, electromagnetic soundings, 3D seismics and VSP- reflectors, resulting in six site-scale and 84 local-scale fault zones. For each fault zone, a core has been defined on the basis of geological and geophysical data and, in addition, for selected zones, including influence zones. The widths of cores range from metre- scale to few-metre scales whereas the influence zones usually have a width in scales of tens of metres. 250 251
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APPENDICES
Appendix I. Map of observation points
Appendix II. Applied geophysical data
Appendix III. Preliminary fault analysis
Appendix IV. Lithological map
Appendix V. Simplified lithology from drillholes
Appendix VI. Assessment of the applicability of lineament data
Appendix VII. Site-scale zones
Appendix VIII. Local-scale zones
Appendix IX. List of modifications for zones compared to model version 0
Appendix X. Vertical and horisontal profiles of the fault zones
Appendix XI. Influence zone definitions
Appendix XII. Structural interpretation map of Olkiluoto 276 277 APPENDIX I 278 279 APPENDIX II
APPLIED GEOPHYSICAL DATA
Overview
The following text introduces the geophysical data applied in the current modelling work, with proper references to published reports. The first part of the Appendix describes the surface-based geophysical investigations and the last part the subsurface investigations.
Surface data
Airborne geophysics
Geophysical airborne data has been available from two separate survey campaigns done by GTK and Scintrex (Suomen Malmi 1988). The airborne data include the following methods:
- Magnetic (total field and vertical gradient) - Multifrequency EM with 888, 3113 (GTK) 7837 and 51250 Hz - VLF - Radiometric (K, U, Th, total intensity)
Figure 1 and Figure 2 show the magnetic data from both surveys.
The first interpretations of the data have been carried by Paananen and Kurimo (1990), followed by two lineament interpretations (Paulamäki & Paananen 2001, Paulamäki et al. 2002). The most recent lineament interpretation, combining systematically topographic and geophysical data, has been done by Korhonen et al. (2005). 280 APPENDIX II
Figure 1. Aeromagnetic data around Olkiluoto by GTK. Map from Korhonen et al. (2005). 281 APPENDIX II
Figure 2. Aeromagnetic data by Scintrex (Suomen Malmi 1989). The frame indicates the site model area. Map compiled by GTK (Korhonen et al. 2005).
Ground geophysics
Geophysical ground surveys comprise magnetic (Figure 4) and horizontal-loop EM measurements (Suomen Malmi Oy 1989, Lahti 2004). Furthermore, seismic refraction (Lehtimäki 2003a,b; Figure 5, Ihalainen 2005) and wide-band electromagnetic soundings (Jokinen 1990, Jokinen & Jokinen 1994, Ahokas 2003, Jokinen & Lehtimäki 2004) have been carried out as several separate campaigns. Impulse radar soundings and interpretations have been done as reconnaissance lines (Koskiahde 1988) and along investigation trenches TK3, TK4 and TK7 (Sutinen 2002, 2003). In the areas of thick soil layers, the penetration depth of radar waves is strongly limited, but in exposed areas, it provides a high-resolution picture of shallow bedrock fractures. 282 APPENDIX II
The magnetic data have been used in delineating most intensely magnetized rock type units. According to petrophysical data (Lindberg & Paananen 1991a, 1991b, 1992, Paananen & Kurimo 1990, Paananen 2004), susceptibility does not directly indicate different rock types. However, the most significant magnetic anomalies are related to ferrimagnetic, pyrrhotite-bearing gneisses (veined gneisses, mica gneisses, diatexitic gneisses). According to the systematic 3D profile modelling, the dips of the magnetized units become gentler with depth, agreeing well with the foliation observations in the drillholes. Furthermore, the main brittle deformation zones appear to coincide with the contacts of the magnetized units (Figure 3).
Figure 3. Magnetic profile interpretation, easting = 1525900.
Figure 4 and Figure 5 show ground magnetic and seismic refraction data and the lineaments (Korhonen et al. 2005) interpreted according to these datasets. 283 APPENDIX II
Figure 4. Lineaments interpreted from ground magnetic data (Korhonen et al. 2005). Outer frame depicts the site model area and the inner frame the ONKALO-area.
Figure 5. P-wave velocity data (Lehtimäki 2003a,b) and interpreted lineaments, related to low-velocity zones (Korhonen et al. 2005). Black frame depicts the location of the ONKALO-area. 284 APPENDIX II
The latest interpretation of supplemented HLEM (Slingram) data has been carried out by Paananen et al. (2007). The survey has been conducted utilising the frequencies 1760 and 14080 Hz and coil separation of 100 m. The maximum investigation depth for the used configuration is about 50…100 m depending on dimensions, shape and electrical parameters of a conductor, host rock and overburden. Figure 6 shows the map of the measured quadrature component with 14080 Hz frequency.
Figure 6. Quadrature data, frequency 14080 Hz.
The HLEM results were interpreted by visually delineating the conductive zones and by classifying the features according to anomaly intensities and in-phase/quadrature ratios (Paananen et al. 2007) (Figure 7). The results were also correlated to known overburden conditions and other known electric conductors. Some HLEM profiles were also modelled with the program EMPLATES (Pirttijärvi 2003; Fig. 3), indicating gentle dips (30 – 45 degrees) to the south. The used model is a thin sheet embedded in conductive halfspace.
A majority of the interpreted conductors are ENE-WSW trending features (Figure 8). The most distinct ones are probably sulphide-rich zones. Less significant anomalies are typically related to bedrock depressions with a relativety thick soil cover and a zone of weakness below. Accordingly, the interpreted HLEM conductors can be considered as potential locations of deformation zones. 285 APPENDIX II
Figure 7. Calculated Re/Im-ratio, frequency 14080 Hz.
Figure 8. Locations of interpreted electric conductors, HLEM survey. 286 APPENDIX II
SAMPO Gefinex wide-band electromagnetic soundings have been carried out at Olkiluoto as five separate campaigns in 1990, 1994, 2002, 2004 and 2007 (Jokinen 1990, Jokinen & Jokinen 1994, Ahokas 2003, Jokinen & Lehtimäki 2004, Korhonen & Lehtimäki 2007) (Figure 9). They have been used in mapping deep saline groundwaters, but they also give information on sulphide minerals and possible deformation zones related to sulphide-rich locations. Previous interpretations have been done for each survey campaign (Paananen et al. 1991, Jokinen et al. 1995, Heikkinen et al. 2004a), but they are all separate works and somewhat incoherent. The data from different years were uniformly interpreted, taking also into account the known electric conductors (Paananen & Jääskeläinen 2005, Paananen et al. 2006) (Figure 10). The survey results reveal several gently dipping/subhorizontal features, supporting especially the existence of site-scale fault zones OL-BFZ080 and OL-BFZ098 and suggesting their continuation in the N/NW (Figure 11).
1523000 1523500 1524000 1524500 1525000 1525500 1526000 1526500 1527000 1527500 1528000 1528500
Olkiluoto 6793500 6793500
! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! 6793000 ! ! ! ^ 6793000 ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !!!!!!! !!! !! !!!!! ! !!! !!!!! ! !!!!! ! !! !! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !!! ! ! ! ! ! ! ! ! !! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! 6792500 ! ! 6792500 ! ! ! ! ! !!! ! ! ! ! ! ! ! !!! ! ! ! ! !! ! !!!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! !! ! !!! ! ! ! ! !! ! ! ! ! ! ! !!!! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! !!! ! ! ! ! !! ! ! ! ! ! ! !! ! ! ! !! !! ! ! ! ! ! ! ! ! ! ! !!! ! ! !!!! ! ! ! !! !!! !!!!! ! !!!!!!! !! !!! !!!! ! ! ! ! ! ! !! ! ! ! ! 6792000 ! ! ! 6792000 ! ! !! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! !! ! !! !!! !! !! ! !! !! !! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 6791500 6791500 ! ! ! 6791000 6791000
Buildings ! Sampo soundings 1990 Transformer station Fields ! Sampo soundings 1994 High-voltage powerline
6790500 ! Sampo soundings 2002 Powerline 6790500 Meadows ! Sampo soundings 2004 Major road Outcrops Research area Minor road Wetlands 0 0.5 1 1.5 2 2.5 km 6790000 Water 6790000
1523000 1523500 1524000 1524500 1525000 1525500 1526000 1526500 1527000 1527500 1528000 1528500
Figure 9. Map of Olkiluoto and the locations of Sampo-gefinex soundings. The most recent survey area is indicated by a red rectangle (Korhonen & Lehtimäki 2007). 287 APPENDIX II
0Z
-500Z Ohmm 0 – 500 500 - 1000 1000 - 3000 3000 -
Figure 10. SAMPO-Gefinex interpretation from vertical section Y =6791900, coil separation = 200 m. The red sections represent interpreted conductors, related to sulphide rich zones. Arrows indicate the locations of probable ground exposures of the conductors (Paananen & Jääskeläinen 2005).
Figure 11. Two distinct SAMPO-Gefinex conductors (brown colour), related to brittle fault zones OL-BFZ080 and OL-BFZ098 (green colour).
The most recent Sampo-Gefinex survey was carried out in order to study the electrical structure of southeastern part of the site (Korhonen & Lehtimäki 2007) (Figure 12). In general, the interpretations indicate three conducting horizontal or subhorizontal layers. However, the interpretations of the 200-m and 400-m coil separation soundings from 288 APPENDIX II some lines indicate two layers. The top layer appears to be horizontal, whereas the bottom layer seems to be dipping ca. 20° to the SE .
Figure 12. Interpretations of the soundings from one survey line in the southeastern part if the site. Top panel: the interpretations of the 200-m coil separation soundings. Middle panel: the interpretations of the 400-m coil separation soundings. Bottom panel: the interpretations of the 800-m coil separation soundings. Gaps indicate soundings that could not be interpreted. The dashed line indicates the depth of one coil separation (Korhonen & Lehtimäki 2007).
Surface 3D seismics
In order to assess the potential of 3D seismics for imaging the upper 1 km of the crust and to gain some structural information, a 3D seismic pilot study was carried out at Olkiluto in 2006 (Juhlin & Cosma 2007). The survey covered an area of about 650 m x 600 m, using a fixed receiver array and a mechanical VIBSIST source. Figure 133 shows the map of the survey and in Table 1, some technical information on the survey is presented. 289 APPENDIX II
Figure 13. Location map of the seismic 3D reflection survey (Juhlin & Cosma 2007).
The reflection seismic method used provides information on the bedrock from about 100 m depth down to depths of several km. Basically, it is not possible to give any exact detectability limit for geological structures, since it depends on so many factors (contrast in elastic parameters and dimensions of the reflector). The contrasts in Olkiluoto are typically rather small, and, accordingy thicknesses down to ¼ of wavelength are considered adequate. In the frequency range 100 – 700 Hz and P-wave velocities 5000 – 6000 m/s this corresponds to thicknesses between 7.5 and 15 metres (Saksa et al. 2007). Previous experiences from 2D reflection seismic surveys (Juhlin et al. 2004) indicate that structures dipping up to 75º can be imaged by this method.
Related to this survey, numerical 2D modelling has been done to assess the detectability of faulting of seismic reflectors (Saksa et al. 2007). According to this study, a vertical displacement of 10 – 20 m can be detected with 100 – 700 Hz frequency. However, below the depth of 600 m the displacement must be over 20 metres.
Reflectors from about 100 m down to at least 3 km are imaged by the survey. Two groups of reflections are observed, (1) sub-horizontal zones of reflectivity at 200-300 ms (600 – 900 m), 450-550 ms (1350 – 1650 m) and 900-1000 ms (2700 – 3000 m), and (2) reflections corresponding to structures striking nearly in the W-E direction and dipping 25-30 degrees to the south (Juhlin & Cosma 2007).
Figure 14 shows an example of the seismic 3D reflection data. 290 APPENDIX II
Table 1. Acquisition parameters for the 3D pilot survey at Olkiluoto 2006 (Juhlin & Cosma 2006).
Parameter Value Receiver line spacing / number 60 m / 9 Receiver station spacing / channels 24 m / 30 Source line spacing / number 100 m / 7 Source point spacing / number per line 10 m / 71 CDP bin size 12 m x 12 m Nominal fold Highly variable Geophones 28 Hz single Sampling rate 1 ms Record length 30 s raw Source VIBSIST: 2000-2500 J/impact at 200-800 impacts/minute on a steel/aluminium plate of 800 mm x 800 mm mounted on a 13 ton tractor, source signal sent via radio to recording system Instrument SERCEL 408UL
For further modelling and correlation with other data, the most distinct seismic reflectors have been digitized from the vertical reflector maps and constructed as surfaces (Figures 15, 16 and 17). The reflectors appear to be frequently discontinuous and displaced, suggesting a number of potential steeply dipping fault zones. 291 APPENDIX II
Y=6792453.791 X=1526049.988
Y=6792803.55 Y=6791955.141 X=1525490.21 X=1525738.378 Y=6792304.9 X=1525178.6
Z= -1200
Figure 14. Results from the 3D seismic survey (Juhlin & Cosma 2006), strong reflectors are shown in red/blue. View from WSW. 292 APPENDIX II
0 m
900 m
Figure 15. 3D seismic reflection map and its interpretation, NW-SE trending vertical section. Cyan lines: upper boundaries of main seismic reflectors, black lines: possible faults, cutting the reflectors. 293 APPENDIX II
Figure 16. Digitized reflecting features from 3D seismic reflection survey (blue lines), view from SW.
Figure 17. Digitized reflecting features from 3D seismic reflection survey as surfaces, view from SSW.
In addition to 3D seismic survey, 2D reflection processing from the original seismic refraction data has been carried out (Öhman et al. 2007). Interpreted 2D reflectors have been combined to 3D surfaces (Figure 18). Most of the reflecting features are gently dipping. The most distinct and continuous features are detected between drillholes KR7 and KR29 at the depth of c. 200 – 300 m. These reflectors corresepond well to the 294 APPENDIX II brittle fault zones BFZ098 and BFZ080 at several locations, supporting their existence and orientation (Figure 19).
Figure 18. Interpreted reflectors from 2D reflection processing (Öhman et al. 2006). Original data is from refraction seismic surveys. View from SW. Arrows indicate the most continuous reflectors related to brittle fault zones OL-BFZ080 and OL-BFZ098.
Comparison of 3D and 2D seismic reflection results shows that the main features are coherent. Their overlapping area is rather small, but the results clearly reveal the same continuous gently dipping features, representing fault zones in the geological model (Figure 20). 295 APPENDIX II
Figure 19. Interpreted reflectors from 2D reflection processing (in brown; Öhman et al. 2006) with brittle fault zones OL-BFZ080 and OL-BFZ098 (in green ).
Figure 20. Seismic reflectors from 3D (blue lines) and 2D (brown surfaces) reflection seismics, related to fault zones OL-BFZ080 and OL-BFZ098. Green lines depict drillhole sections. 296 APPENDIX II
Subsurface data
Single-hole geophysics
The single-hole geophysical data were available from deep drillholes OL-KR1…OL- KR40. (Niva 1989, Suomen Malmi Oy 1989, 1990, Julkunen et al. 1995, 1996, 2000a,b, 2002, 2003, 2004b,c, Julkunen & Kallio 2005a,b, Laurila & Tammenmaa 1996, Lowit et al. 1996, Lahti et al 2001, 2003, Heikkinen et al. 2004b, Lahti & Heikkinen 2005b, Majapuro 2005a,b, 2006a,b, Tarvainen 2006). Furthermore, data from pilot holes OL-PH1 (Julkunen et al. 2004a) and ONK-PH2…ONK-PH4 (Lahti & Heikkinen 2005a) have been utilised. The locations of the drillholes are presented in Figure 21.
The single-hole data gathered comprises different seismic (p-wave and s-wave velocity, p-wave and tubewave attenuation), radiometric (gamma-gamma, neutron-neutron), electric (long normal, short normal/wenner), magnetic, thermal and caliper data. The seismic, radiometric, and electric parameters have been mainly used in determining the locations of the deformation zones (however sulphides have a strong effect on electric measurements). The magnetic data are mainly used in locating ferrimagnetic, pyrrhotite- rich sections.
Logging of gamma-ray spectrum in drillholes KR1, KR4 and KR27 was a new method applied in 2005 (Julkunen & Kallio 2005a,b). This survey provides K, equivalent U and equivalent Th content and total gamma radiation along the drillholes.
Figure 21. Locations of the drillholes in Olkiluoto. Black frame: site model area, blue frame: ONKALO model area. 297 APPENDIX II
Figure 22 presents the profiles of the most important geophysical single-hole parameters from drillhole OL-KR23. Table 2 shows the interpretation in details.
Figure 22. Single-hole geophysics and its interpretation, OL-KR23 (Paananen et al. 2006). Rasterized area = fracturing, red = sulphides. 298 APPENDIX II
Table 2. Interpretation of drillhole OL-KR23 as an example, fractured and sulphide- rich sections (Paananen et al. 2006).
Location (m) Character integrated interpretation 36.7-42.3 fracturing 44.0-46.6 fracturing 47.6-56.4 intense fracturing 67.7-68 fracturing 70-73 fracturing? 85.4-89 fracturing 134.0-142 open? fracturing 104-187 pyrhotite (several separate anomalies) 173.5-177.5 Intense fracturing, pyrrhotite 194-202.9 fracturing,pyrrhotite 244-246.6 fracturing 259-260.9 fracturing 265-269 intense fracturing
Petrophysics
From Olkiluoto area, petrophysical measurements have been done from OL-KR1 – OL- KR6 (Lindberg & Paananen 1991a, 1992), bedrock outcrops and shallow drillholes (Paananen & Kurimo 1990) and the VLJ repository (Lindberg & Paananen 1991b). The data has been supplemented by the results from OL-KR8, OL-KR15, OL-KR19 – OL- KR23 and 24 minidrill samples from the ground surface (Paananen 1994).
Mise-a-la-masse
Mise a-la-masse surveys have been carried out at Olkiluoto as five separate campaigns in 1995 (Laurila 1995; Paananen 1996), 2003 (Lehtonen & Heikkinen 2004), 2004, 2005 and 2006 (Lehtonen 2006, Lehtonen & Mattila 2007). They have been used in mapping fracture zones, but they also give information on sulphide minerals and possible deformation zones related to sulphide-rich locations.
The total number of different current earthings is 48 (Table 3 and Figure 23) and potential measurements have been done in 27 drillholes and in the Onkalo tunnel (Table 4). Furthermore, potential measurements have been done along survey lines on the ground surface. Figure 24 shows some planar/semi-planar gently dipping electric conductors defined by the Mise-a-la-masse surveys. In Table 5, a collation of the survey results is presented, indicating numerous potential electric connections. Figure 25 shows a vertical section of potential distribution for current earthing KR4_759 m and the probable geometry of the conductor. 299 APPENDIX II
Table 3. The current earthings (Lehtonen 2006).
HoleID Hole Depth Easting Northing Elevation KR1 102,00 1525530,80 6792388,33 -88,26 KR1 155,00 1525524,27 6792402,20 -140,04 KR25 60,00 1526013,00 6792094,00 -48,00 KR25 70,00 1526015,00 6792096,00 -57,00 KR25 122,00 1526026,00 6792109,00 -107,00 KR25 383,00 1526079,00 6792172,00 -356,00 KR25 518,00 1526104,00 6792202,00 -484,00 KR27 96,80 1526479,00 6791911,00 -72,00 KR27 296,00 1526369,00 6791955,00 -229,00 KR27 338,00 1526344,00 6791967,00 -264,00 KR27 392,00 1526316,00 6791982,00 -303,00 KR28 178,00 1526005,00 6792005,00 -131,00 KR28 245,00 1525985,00 6792037,00 -187,00 KR28 368,00 1525949,00 6792096,00 -288,00 KR28 442,00 1525929,00 6792136,00 -350,00 KR29 130,00 1525570,00 6791819,00 -114,00 KR29 213,00 1525550,00 6791840,00 -193,00 KR29 335,00 1525523,00 6791871,00 -308,00 KR29 762,00 1525446,00 6791996,00 -707,00 KR3 158,00 1524978,07 6792374,86 -136,78 KR3 242,00 1524950,20 6792396,36 -215,24 KR3 390,00 1524898,55 6792437,30 -347,74 KR33 98,00 1525178,00 6792839,00 -74,00 KR33 117,00 1525171,00 6792844,00 -84,00 KR33 151,00 1525159,00 6792865,00 -114,00 KR33 275,00 1525114,00 6792934,00 -208,00 KR37 323,00 1525987,00 6791995,00 -229,00 KR4 58,00 1525889,15 6792030,67 -47,41 KR4 80,00 1525888,00 6792035,00 -68,00 KR4 116,00 1525885,00 6792043,00 -103,00 KR4 135,00 1525884,86 6792047,48 -122,38 KR4 314,00 1525874,00 6792088,00 -296,00 KR4 368,00 1525870,00 6792100,00 -348,00 KR4 394,00 1525868,10 6792106,91 -373,87 KR4 490,00 1525859,64 6792131,12 -466,37 KR4 490,00 1525859,00 6792131,00 -466,00 KR4 759,00 1525831,00 6792210,00 -722,00 KR7 416,00 1525645,00 6792227,00 -381,00 KR8 60,00 1526086,24 6791871,34 -41,91 KR8 80,00 1526089,00 6791863,00 -60,00 KR8 162,00 1526103,00 6791832,00 -132,00 KR8 354,00 1526131,54 6791753,96 -307,58 KR8 552,50 1526150,88 6791670,78 -486,19 Onkalo 283,00 1525844,90 6792106,27 -23,79 Onkalo 721,00 1526110,42 6792030,66 -65,59 Onkalo 899,00 1525978,07 6791973,87 -82,63 Onkalo 952,00 1525940,93 6792009,25 -87,23 Hall 0,00 1525943,00 6792007,00 8,50 300 APPENDIX II
Table 4. The measured drillholes of the separate survey campaigns (Lehtonen 2006).
Drillhole 1995 2003 2004 2005 2006 KR1 X X X KR2 X KR3 X X KR4 X X X X KR5 KR6 X KR7 X X X KR8 X X X KR9 KR10 X X KR11 KR12 KR13 X KR14 X X KR15 KR16 KR17 KR18 KR19 X KR20 KR21 KR22 X X KR23 X X KR24 X KR25 X X KR26 KR27 X KR28 X KR29 X KR30 X KR31 X KR32 X KR33 X KR34 KR35 X KR36 X X KR37 X X KR38 X X KR39 X Onkalo X X 301 APPENDIX II
Marikarinnokka 1524500 E 1524500 E 1525000 E 1525500 E 1526000 E 1526500 E 1527000
Selkänummenharju KR6 6793000 N 6793000 N
KR19
KR33
KR5 KR21 KR13
KR20 KR11 KR12
KR2 KR32 6792500 N 6792500 N KR15
KR16 Korvensuon allas KR3 KR17 KR14 KR1 KR18
KR39 KR10
KR30 KR36 KR22 KR7 KR34 KR31 KR25 KR9
Flutanperä KR24 KR35 6792000 N 6792000 N KR38 KR4 KR26 KR23 KR27 KR28 KR8
KR29
KR37
Liiklanperä
6791500 N 6791500 N 1524500 E 1524500 E 1525000 E 1525500 E 1526000 E 1526500 E 1527000
Figure 23. Locations of the current earthings in Mise-a-la-masse surveys, plan view (Lehtonen 2006).
Figure 24. Some electric conductors defined by mise-a-la-masse cross-hole survey, view from SW. The frame indicates the Site area. 302 APPENDIX II
Table 5. Mise-a-la-masse survey, a portion of the drillhole results. Grounding locations (columns) and measured drillholes (rows). The numbers indicate depth of the galvanic connection from the measured drillhole to the grounding location. Yellow: good electric connection, green: fair electric connection (Lehtonen 2006).
KR4KR7 KR25 KR28
80 116 314 368 490 760 416 122 383 518 179 245 368 442
KR1 165 165 355 530
KR2 75-125 75-125 470 surface surface 55-150 55-150
KR4 489 135 180 290 390
KR6
KR7
KR8 180-250 330,440,540330,440,540 250 310 310 330,440,540
KR10 424 surface 230 460
KR13 surface 120 150-290 surface surface 55-115 105
KR14 surface surface 215 215 beneath surface 70-105 170.215 215
KR19 75 75 445 105-135 105-135
KR22 150 190 310 450 beneath 192 442 beneath 185-200 265-285 310 445
KR23 220 beneath beneath 225 255-300 285-350 435/beneath
KR24 90 130-145 325 395 beneath beneath 148 345-485 345-485 134 174 308 350-405
KR25 460-580
KR27 250-305 beneath beneath
KR28 155 180/200 390 430 beneath 180 440 600
KR29 80 80 330 330 855? 490 75 165-215 305-365 305-365
KR30 surface surface beneath beneath beneath surface beneath beneath
KR31 beneath beneath beneath beneath beneath beneath beneath beneath beneath beneath beneath beneath
KR32 surface surface beneath surface surface surface surface
KR33 surface surface 270-275
Tunnel 100959090 303 APPENDIX II
KR25 KR4 KR8 KR33 KR21 KR1 KR30 KR24 KR26 KR28 PH2
6793600 N 6793600 0 RL N 6793400 E 1524800 N 6793200 E 1525000 N 6793000 E 1525200 N 6792800 E 1525400 N 6792600 E 1525600 N 6792400 N 6792200 E 1525800 N 6792000 E 1526000 0 RL N 6791800 PH1
KR 20
-200 RL -200 RL
KR7
KR 22 -400 RL -400 RL
-600 RL -600 RL
-800 RL -800 RL
-1000 RL -1000 RL
-1200 RL -1200 RL
-1400 RL -1400 RL 6793600 N 6793600 N 6793400 E 1524800 N 6793200 E 1525000 N 6793000 E 1525200 N 6792800 E 1525400 N 6792600 E 1525600 N 6792400 N 6792200 E 1525800 N 6792000 E 1526000 N 6791800
Figure 25. Geometry of a conductor according to mise-a-la-masse survey (Lehtonen 2006). The current grounding was located in KR4 at the depth of 759 m. NW-SE trending vertical profile.
In addition to interpretations based on single current earthings, comprehensive cross- hole correlation of the MAM results has been done (Paananen et al. 2007). Table 6 shows a compilation of all those current earthings, which have an interpreted electrical galvanic linkage to one or more conductors in other drillholes. Furthermore, a part of the observed electrical connections with separate current earthings can be linked together. Mise-a-la-masse conductors with current earthings KR4_80m, P283 and P952 can be combined together (OL-MAM-001), likewise current earthings KR4_116m, KR25_122m and KR28_178m (OL-MAM-002), current earthings KR4_314m and KR28_368m (OL-MAM-003), current earthings KR4_368m, KR25_383m and KR28_442m (OL-MAM-004) and current earthings KR4_490m and KR7_416m (OL- MAM-005).
Drillholes KR27 and KR29 are situated far from the other drillholes, and thus the continuations of those electrical structures are very uncertain. In general, probable electrical links to drillholes farther away are more troublesome to interpret. 304 APPENDIX II
Table 6. Numbering of the mise-a-la-masse conductors.
Current MAM-conductor earthing numbering KR4_80m OL-MAM-001 KR4_116m OL-MAM-002 KR4_314m OL-MAM-003 KR4_368m OL-MAM-004 KR4_490m OL-MAM-005 KR4_759m OL-MAM-006
KR7_416m OL-MAM-005
KR25_60m OL-MAM-007 KR25_122m OL-MAM-002 KR25_383m OL-MAM-004 KR25_518m OL-MAM-008
KR28_179m OL-MAM-002 KR28_245m OL-MAM-009 KR28_368m OL-MAM-003 KR28_442m OL-MAM-004
P283 OL-MAM-001 P721 OL-MAM-010 P899 OL-MAM-011 P952 OL-MAM-001
Hall OL-MAM-012
KR37_323m OL-MAM-013
KR27_296m OL-MAM-014 KR27_338m OL-MAM-015 KR27_392m OL-MAM-016
KR29_213m OL-MAM-017 KR29_335m OL-MAM-018
Electrical model of Olkiluoto
Based on integrated interpretation of electrical single-hole measurements (Figure 26), MAM results, SAMPO wide-band EM soundings and HLEM (Slingram) survey, a combined electrical model of Olkiluoto has been compiled (Paananen et al. 2007). The basic idea of this work is the fact that the sulphide-rich zones and fracturing appear to coincide frequently. Accordingly, knowing the geometry of the major electric conductors would facilitate the interpretation of brittle deformation zones. 305 APPENDIX II
The starting point of the electrical model was the correlation between the MAM results and local drillhole conductors (drillholes KR1 – KR39 and PH1 – PH4). The MAM results indicated the general geometry and the conductive sections to be combined, whereas the drillhole conductors revealed the thickness and resistivity of the conductor. The conductor was also extended to the ground surface according to Slingram interpretations. The correlation of SAMPO conductors with other data was more difficult, since the scale of the investigation in EM soundings is different from standard drillhole surveys. However, the interpreted SAMPO conductors indicate that some drillhole conductors can probably be extended to the N/NW.
Figure 26. Interpreted conductive sections. Minimum apparent resistivity values: red: < 500 ohmm, orange: 500 – 1000 ohmm, green: 1000 – 5000 ohmm. View from NE.
The electrical structure of Olkiluoto is dominated by mineral electrical conductors such as sulphide minerals and graphite. Sulphidisation is recognized mainly as pyrrhotite disseminations, and, to a lesser degree, as pyritic platings and pyrite vein stockworks. Sulphidised migmatites may contain several percent of disseminated pyrrhotite, occurring also in fractures. The thickness of these sulphide-rich zones varies from a few centimetres to several metres (Paananen et al. 2006). Deeper in the bedrock, groundwater is also highly saline, decreasing the total bedrock resistivity. Fracturing can also be observed as decreased resistivity due to elevated fracture porosity. The resistivity of a fracture zone depends highly on porosity, fluid resistivity and the occurrence of mineral conductors.
The overall picture of electrical drillhole conductors at Olkiluoto is rather simple (Figure 27): most of the conductors are located near the ground surface at the depth of 0 – 200 m. Almost in every drillhole, there is a conductor-free section of c. 300 - 400 metres. Below this section, another conductor-rich section is found in several holes. 306 APPENDIX II
However, in detail the geometry of the conductors is much more complicated. The conductive sections typically consist of a set of narrow semi-parallel sulphide-rich horizons.
Conductors
No significant conductors
Conductors
Figure 27. Overview of drillhole conductors, view from E.
In the electrical model of Olkiluoto, the geometry and properties of 16 gently dipping/horizontal conductive structures have been defined (Figure 28).
Figure 28. Interpreted conducting structures, view from SW. 307 APPENDIX II
Seismic drillhole measurements
Vertical seismic profiling (VSP) surveys have been carried out as several campaigns in 14 drillholes (KR1-KR10, KR12-KR14, KR19) at Olkiluoto, starting from 1990. Over the years, the survey technique as well as the interpretation procedure have been greatly developed. In this study, the VSP interpretation results from each drillhole in the site model area have been examined and correlated to geological data. The most recent VSP results are from the following drillholes, located in the ONKALO area:
- KR7, KR8 (Cosma et al. 2003, Heikkinen et al. 2004) - KR4, KR10, KR14 (Enescu et al. 2004, Heikkinen et al. 2004).
Furthermore, HSP results from the Korvensuo reservoir (Cosma et al. 2003) and crosshole surveys between KR14 and KR15 (Enescu et al. 2003) and KR4 and KR10 (Enescu et al. 2004) were available. In addition to this, the results of the Walkaway Vertical Seismic Profiling (WVSP) from drillholes KR4, KR8, KR10 and KR14 (Enescu et al. 2004, Heikkinen et al. 2004) were available.
Since many different geological features may induce seismic reflectors, they must be checked against geological and single-hole geophysical data. A comprehensive validation of VSP results from drillholes KR4, KR7, KR8, KR10 and KR14 have been done by Heikkinen et al. (2004). According to their conclusions, c. 60 – 70% of the gently dipping reflectors can be explained by elevated fracturing. From all the reflectors, c. 30 – 40 % appears to coincide with lithological contacts. Overall, 60 – 70% of the reflectors can be explained with the existing geological data.
The most systematic feature in the single-hole VSP results is the majority of gently dipping reflectors (dip commonly < 30° to SSE), agreeing rather well with geological observations (foliation, fracturing) and Mise-a-la-Masse results.
In Figure 29, intepreted reflecting elements of OL-KR8 are presented as an example. 308 APPENDIX II
Figure 29. VSP reflectors from drillhole OL-KR8. The blue frame indicates the ONKALO model area.
To determine the possible orientations of brittle deformation zones with VSP, the interpreted reflectors of each drillhole (KR1 – KR10, KR12 – KR14, KR19) have been checked against geological data. In Table 7, all those deformation zone intersections and VSP reflectors are listed, where the intersection and the reflector are located within 20 m in the same drillhole. Using the orientations of the VSP reflectors, the zones have been extrapolated to neighbouring drillholes and checked against the geological data. Using this procedure, several potential zones could be determined. However, the VSP reflector orientations usually do no agree with the average orientations of the slickenside fractures. This may be due to the fact that the scale of investigation in VSP is much bigger than single fractures.
Table 7. Correlation of VSP reflectors with deformation zone intersections. Yellow colour: intersection could possibly be extrapolated to neigbouring drillhole(s).
Zone intersection Orientation according to Location and orientation of Extrapolated to fracture data (slickensides) the VSP reflector OL_KR10_DSI_26900_27540 107/73 263.1 m, 160/25 269.12 m, 270.6 m, OL_KR25_BFI_34700_35225 OL_KR10_BFI_27147_27159 115/78, set 2 170/23-24 OL_KR14_BFI_21755_21913 OL_KR10_BFI_32600_32745 319.6 m, 142/26 OL_KR10_DSI_36500_37190 364.9 m, 140/30 OL_KR10_BFI_36690_36985 364.9 m, 140/30 OL_KR10_DSI_49420_52090 515.9 m, 170/17 OL_KR10_BFI_52638_52690 070/46, set 1 c. 520 - 530 m, 160/40 OL_KR20_BJI_18811_19271 OL_KR13_SFI_21593_21985 220.9 m, 164.4/74.8 OL_KR13_BFI_24584_25500 143/41, set 3 250 m, 180/5 scattered, one observation OL_KR13_BFI_31880_32500 317.5 m, 150/65.3 170/60 scattered, two OL_KR13_BFI_36275_37446 379.9 m, 270/83 observations 262/78 OL_KR13_BFI_40941_42389 140/37, set 2 401.5 m, 130/59.9 OL_KR13_BFI_44550_46800 148/36, set 1 or 3 451.8 m, 141.6/77.2 OL_KR13_BFI_47500_48052 056/54, set 3 485.8 m, 139.3/73.7 309 APPENDIX II
OL_KR15_BFI_44962_45600 OL_KR13_BFI_31880_32500 079/37, 175/22, 266/66, 430 m, 152/32; 461.1 m, KR7, fractures set 1: 577.41 - OL_KR14_BFI_44500_44908 set 1,2,3 162/34.4 586.35 OL_KR21_BFI_27577_28100 OL_KR19_BJI_15517_15698 OL_KR13_BFI_36275_37446 OL_KR14_BFI_46985_47623 118/40, set 2 or 4 461.1 m, 162/34.4 OL_KR19_BFI_17458_18675 OL_KR19_BJI_15517_15698 155.3 m, 157.5/9.7 OL_KR13_BFI_22025_22596 OL_KR19_BFI_17458_18675 137/33, 073/24, set 3 172 m, 219.7/34.6 OL_KR1_BFI_53860_53963 OL_KR19_BFI_19967_20089 160/39, set 3 204.4 m, 168.3/23.3 OL_KR13_BFI_31880_32500 OL_KR19_BJI_20234_20286 204.4 m, 168.3/23.3 OL_KR19_BFI_20986_21153 169/45, 118/44, set 3 204.4 m, 168.3/23.3 284.6 m, 123.6/75.6; 304 OL_KR3_BFI_38780_39110 OL_KR19_BJI_29561_29755 180/74, 52/26, 315/06 m, 158.8/18.6 OL_KR13_BFI_40941_42389 seismic lineament OL_KR13_BFI_47500_48052 OL_KR19_BJI_40538_40882 412.6 m, 252.9/74.8 OL_KR32_BJI_17526_17678 OL_KR2_BFI_4556_4668 OL_KR15_BFI_44962_45600 seismic lineament OL_KR13_BFI_47500_48052 OL_KR19_BFI_41236_41462 157/26, set 3 412.6 m, 252.9/74.8 OL_KR32_BJI_17526_17678 OL_KR2_BFI_4556_4668 OL_KR15_BFI_44962_45600 KR5, fracture set 1: 166.69 m OL_KR19_BFI_46475_46532 scattered, 179/28, set 2 455.1 m, 120.8/65.1 KR20, fracture set 1: 390 m KR1 fracture set 1: 556.56 m 186/23, 120/68, 138/21, OL_KR19_BFI_52715_52899 535.3 m, 217.6/47.1 set 1 or 2 OL_KR19_BFI_53327_53591 099/38, set 2 535.3 m, 217.6/47.1 OL_KR2_BFI_60080_60477 OL_KR7_BFI_22701_22880 OL_KR3_BFI_15820_16275 182/64, 190/50, set 3, 1 165 m, 175/15 VSP 180/10 OL_KR3_DSI_28550_29050 181/23, 167/31, set 2, 4 279.9 m, 115/86 OL_KR3_DSI_38730_39385 392.5 m, 110.2/84.3 OL_KR3_BFI_38780_39110 392.5 m, 110.2/84.3 OL_KR3_DSI_42724_43090 440.1 m, 162/28 77.3 m, 200/80; 81 m, OL_KR4_DSI_7300_7400 120/85 77.3 m, 200/80; 81 m, OL_KR4_DSI_8140_8310 120/85 linked lineament 77.3 m, 200/80; 81 m, OL_KR4_BFI_8154_8239 comes to ONKALO at 208 120/85 and 462 m OL_KR25_BFI_57155_57800 OL_KR4_BFI_31340_31615 269/81 319.9 m, 145/83 comes to onkalo at 276 and 429 m 140/57, 162/78, 218/58, OL_KR19_BFI_46475_46532 OL_KR4_BFI_75770_76270 762 m, 160/20 set 3 DISTANCE OVER 500 M OL_KR4_BFI_79100_79200 792 m, 160/20.3 KR1_ BFI_64040_64220 KR33, set 2 fracture at OL_KR5_DSI_10700_12845 114.3 m, 129.7/50.4 168.75 257.7 m, 112/68.5; 258.9 OL_KR5_DSI_25667_26553 m, 170.4/80.6 KR33, set 2 fracture at OL_KR5_BFI_26945_27068 163/27, set 3 259.9 m, 170.4/80.6 168.75 OL_KR5_BFI_27897_28244 285.1 m, 262/66 382.9 m, 235.6/58.3; 424.7 OL_KR5_DSI_39660_41304 m, 230/47.5 OL_KR7_BFI_22701_22880 200 m, 180/10; 231/79 KR8_ BFI_30393_30675 KR2_ BFI_22027_22320 OL_KR7_BFI_28570_28640 276 m, 169/8 KR22_BFI_33765_34045 KR29_BJI_33046_330_86 KR2_ BFI_22027_22320 OL_KR7_BFI_28732_28870 276 m, 169/8 KR22_BFI_33765_34045 KR29_BJI_33046_330_86 OL_KR7_DSI_40882_41390 424 m, 175/11 310 APPENDIX II
OL_KR7_BFI_40925_41040 201/49 424 m, 175/11 KR10_ BFI_36690_36985 OL_KR7_BFI_68990_69200 258/21, set 3 680 m, 252/82 KR4_ BFI_75770_76270 OL_KR7_BFI_69410_70210 705 m, 160/25 VSP correlates OL_KR7_DSI_69675_70025 705 m, 160/25 OL_KR8_BJI_10300_10770 103-114 m, 150/39-41 OL_KR8_BFI_13822_13994 140-156 m, 150/38-40 KR27_ BFI_26130_26200 KR27_ BFI_30256_32607 OL_KR8_BFI_30393_30675 092/64, set 1 293 m, 160/19 KR22_BFI_18845_20050 orientations agree! OL_KR8_BFI_34848_35265 360-368 m, 345/61-63 OL_KR8_BFI_37600_38300 349/34, 205/23, set 1 360-368 m, 345/61-63 540 m, 170/16; 552-566 m, OL_KR8_BJI_54200_56200 170/ 18-19 105-110 m, 131/62 class II OL_KR1_BFI_10851_11036 185/58, set 3 - III KR7, set 1 fracture at 493.63 KR13_BFI_24584_25500 OL_KR1_BJI_14118_14395 130 m, 131/68 class II KR15_BFI_49350_49650 KR20_ BFI_46362_47071 KR29_BFI_77651_78102 OL_KR1_BFI_52520_52620 530 m, 160 /27, class II KR7_BFI_69410_70210 KR2_ BFI_50404_50795 OL_KR1_BFI_53860_53963 304/33, 179/53, set 1, 2 530 m, 160 /27, class II KR7_BFI_69410_70210 KR5_ BFI_27897_28244 OL_KR2_BFI_22027_22320 205 m, 213/66 KR12_BFI_20245_20600 KR14_BFI_44500_44908 OL_KR2_BFI_103930_104095 1010 m, 170/37 OL_KR6_DSI_3270_5023 30 m, 180/10, class III KR2, S1 & S2 fractures at OL_KR6_BFI_12322_12945 028/52 110 m, 255/78 521 m OL_KR6_DSI_20470_21666 183 m, 225/57, class II OL_KR6_BFI_50596_50933 091/18, set 2 500 m, 255/70
OL_KR9_BFI_14733_14956 095/15, set 1 140 m, 170/40 class II KR22_BFI_13880_14605 KR27_BFI_33519_33994 OL_KR9_BJI_44420_44510 442 m, 170/21
OL_KR9_BFI_47676_47935 480 m, 170/35, class II KR11_BFI_21290_21660 VSP 169/08 correlates OL_KR11_BFI_21290_21660 144/39, 078/43, set 2 235 m, 169/8 OL_KR11_BFI_62502_62647 635 m, 220/55; 160/25 OL_KR2_BFI_22027_22320 VSP correlates OL_KR12_BFI_20245_20600 244/85, set 5 205 m, 213/65 class II KR5_BFI_27897_28244 VSP correlates OL_KR12_DSI_30525_32435 320 m, 235/44 class II OL_KR12_BFI_66480_66580 174/26 650 m, 225/57 class I
In addition, an integrated VSP interpretation, covering the ONKALO area, has been done (Vibrometric, 2005). In that work, the results from several drillholes have been examined together, and the main focus of interest has been on those reflectors that potentially intersect the tunnel (Figure 30). These reflectors have been examined against geological data (Table 8). 311 APPENDIX II
Figure 30. Integrated VSP reflectors in 3D, view from SW. 312 APPENDIX II
Table 8. Combined VSP reflectors that potentially cut the ONKALO access tunnel, correlation to geological data and single-hole geophysics.
Combined VSP reflectors, correlation to drillhole data Reflector Orientation Drillhole intersections Geological indications Geophysical indications Character
VSP10 c. 195/70 KR10 126.75 BFI 124.95-125.7 P-wave min. 124-125 Steeply dipping fault zone? KR28 583.2 Fracturing 577.6-581 P-wave min. 577-580 RiIV 568.37-568.69
KR7 523.65 BJI 506.4 - 507, PGR P-wave min. 504.5-506 contact 525.6 slickensides 513-514.5
PH6 47.99
VSP12 c. 200/80 KR23 111.5 moderate fracturing, P-wave min. c. 110 Steeply slickensides 109.9, HC dipping 108.5-110.5 fracture zone? KR24 226.06 Fracturing 230 - 232 -- KR28 121.13 Fracturing 126-128, P-wave min. 125.9, 134- PGR contact 132 135
KR37 288.04 KR38 132.82 KR4 74.98 DSI 73-74, 81.4.83.1, P-wave min. 76-77.5 BFI 81.54-82.39, MGN contact 69.2
KR7 104.62 Fracturing 102-103, Susc max 104-105.5 PGR contact 105.5, HC 110-112
PH2 46.66 X X PH3 107.95 PH4 71.06 RiIII 84-85.53 Onkalo c. 180
VSP13 c. 207/78 KR7 c. 309 Fracturing 304-306, HC P-wave min. 303.6 - 304.8 Steeply 305.5-307.5 dipping fracture zone?
VSP15 c. 220/77 KR7 590 RiIII 586.25-586.77 P-wave min. 583-384 Steeply dipping fracture zone? KR10 390 BFI 366.9-369.85, DSI 365-371.9, PGR 408.2, 377.5
KR28 620 PGR 619.95 313 APPENDIX II
Table 8, continued.
Reflector Orientation Drillhole intersections Geological indications Geophysical indications Character VSP24 c. 150/56 KR14 436 BFI 445-449 Pwave min. 447.5-448.5 Fault zone? KR15 420 ILL 417-424, intense fracturing 417-419
VSP56 170/15 KR22 464.67 8 fractures/m at 474-475 P-wave min. 456-457 ? KR24 426.66 7 fractures/m at 423- x 424, PGR/VGN 413.6, HC 422-424 KR27 543.64 RiIII 547.38-549.59 P-wave min. 547-549
KR28 474.12 VGN/PGR 470.35, 472.85, 481.95 KR38 419.64 RiIII 403.07-404.08 P-wave min. 403-405
KR4 404.06 DGN/MGN 404, Mag. max, Res min 403- MGN/DGN 406.3, 405: Pyrrhotite DGN/VGN 410.2
VSP57 236/80 KR25 102 BJI 94.45-97.3, HC P-wave min. 96-97 Brittle steeply dipping joint zone KR28 502 RiIV 520.7-521.77, HC P-wave min. 520.5-522.5
VSP62 180/20 KR22 254.77 Intense fracturing 246- x Brittle fault 248, slickensides, RiIII or joint zone 238-238.98 KR23 324.29 Intense fracturing 327- x 329 (>10/m)
KR24 264.34 Fracturing 256.5-259 P-wave min. 328-329 (max. 7/m), VGN/PGR 257.2, PGR/DGN 260.5 KR25 223.43 BFI 216.5-222.05
KR27 339.62 BFI 335.19-339.94, HC P-wave min. 338-339 KR28 296.56 Lithological variation: P-wave min. 298-301 MFGN, PGR, DGN KR31 301.43 Data?
KR38 256.3 x x KR4 241.8 Fracturing 246-248, max P-wave min. 240.5-241.5 5/m, slickensides 314 APPENDIX II
Table 8, continued.
Reflector Orientation Drillhole intersections Geological indications Geophysical indications Character
VSP64 142/50 KR22 202.37 BFI 188-200.5 P-wave min. 191-196 Brittle fault or joint zone, hydraulically conducting KR24 128.17 BJI 112.55-116.2, HC, P-wave min. 112.6-116.2 MFGN 116.5-119.37, 121.65-124.1
KR28 201.42 VGN/DGN 188.3 x
KR29 60.59 fracturing 61-63 (max.7), x DGN/PGR 65.55 KR37 270.15 x P-wave min. 270-272
KR38 90.84 RiIV88.15-88.75 P-wave min 88-90 KR4 66.21 DSI 73-74, fracturing 60- P-wave min. 59-60, 76- 61, HC, MGN 65.8-69.2 77.5
VSP65 c.75/80 KR23 115 PGR 120-122, HC 108- 107-108, 190-110, 122-123 Brittle joint 110, 116-118, 120-122 zone, hydraulically conducting KR27 484 RiIII 473.66-474.04, HC, X MFGN 485-493.3
KR31 110 BJI 102.5-108, HC X
VSP67 180/49 KR22 166.68 BJI 149.65-152.8, P-wave min. 159.6-160.6, Brittle joint fracturing 164- 165.5-171 zone, DGN/MFGN 172.4 hydraulically conducting KR23 370.02 RiIII 372.5-373, P-wave min. 372-373 slickensides, HC
KR24 290.89 RiIII 305.14-305.94, HC, X HC-fracturing 294-296, DGN/PGR 300.0 KR25 152.85 BJI 149.7-154.15 P-wave min. 153-154
KR28 276.78 MFGN 264.4-267.7, X PGR 275.4-278.15 KR38 265.22 X X
KR4 212.37 X P-wave min. 216.5-217 PH5 151.4 Core loss 151.95-154.93 315 APPENDIX II
Seismic crosshole tomography gives a detailed 2D distribution of P-wave velocity between investigated drillholes. Low-velocity zones are supposed to reflect possible gently dipping deformation zones. Table 9 presents the interpreted low-velocity zones between drillholes OL-KR4 and OL-KR10. The most distinct low velocity zone is related to OL-BFZ080.
Table 9. Low velocity zones in drillholes KR4 and KR10 according to the crosshole tomography (Enescu et al. 2004).
Location in KR4 Corresponding (m) location in KR10 (m) 150 155? 180 155? 230 - 270 180, 220 310 300 – 325? 335 - 380 300 - 325 460 350 – 375? 500 - 515 400 - 430
Drillhole radar surveys have been done in Olkiluoto in 9 drillholes (KR1 – KR8, KR10) as several separate campaigns (Carlsten 1990, 1991, 1996a, 1996b). Since 1996, no new radar measurements in drillholes have been carried out. The applicability of this method is highly limited at Olkiluoto due to saline groundwater and mineral conductors. Furthermore, geological structures intersecting the drillholes at a high angle (>75 degrees) are difficult to detect by drillhole radar. However, drillhole radar results have been used as supporting information. 316 APPENDIX II 317 APPENDIX II
GLOSSARY – GEOPHYSICAL TERMS
EM Electromagnetic (survey method)
VLF Very low frequency EM method, an electrical vertical dipole remote source of 15 --- 20 kHz range
Horizontal-loop EM, HLEM EM method with horizontal loops (Slingram), secondary field In-Phase and Quadrature measured in ppm or %
Wide-band electromagnetic sounding Frequency domain EM survey using a wide band (2 – 20000 Hz) of frequencies
SAMPO EM survey using a wide band (2 – 20000 Hz) of frequencies, horizontal loop transmitter, Hz and Hx receiver (Maxiprobe)
In-phase In-phase component of the measured total EM field
Quadrature Out-of-phase component of the measured total EM field (phase shift 90º)
P wave Compressional/longitudinal seismic wave
S wave Transverse seismic wave
Tube wave Seismic wave propagating along the interface of bedrock/groundwater in the drillhole or fractures, generated in fracture fluid/ rock interface
Long normal Electrode array used in resistivity single- hole logging, potential array, electrode spacing 64 inches
Short normal Electrode array used in resistivity single- hole logging, potential array, electrode spacing 16 inches 318 APPENDIX II
Gamma-gamma Radiometric method; measuring the back- scattered intensity of artificial source gamma radiation in a drillhole, converted to bulk density of rock mass
Neutron-neutron Radiometric method; measuring the back- scattered intensity of neutron radiation in a drillhole, near and far detector counts and ratios are used for mineralogy and water content (porosity) measures
Mise-a-la-masse Galvanic potential drillhole-to-drillhole or drillhole-to-surface survey method
VSP Vertical Seismic Profiling; surface to drillhole application of 3D reflection seismics, fixed source locations at several azimuths and offsets, multicomponent (3C) recording in drillhole
HSP Horizontal Seismic Profiling; ground surface application of fixed source reflection seismics
WVSP Walkaway Vertical Seismic Profiling; surface to drillhole application of 3D reflection seismics, several fixed 3C reflector locations in several drillholes, and a moving seismic source on a continuous ground surface line 319 APPENDIX II
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Lahti, M. & Heikkinen, E., 2005a. Geophysical borehole logging and optical imaging of the pilot hole ONK-PH2. Posiva Oy, Working Report 2005-04, 72p.
Lahti, M. & Heikkinen, E., 2005b. Geophysical borehole logging of the boreholes KR23 extension, KR29 and KR29b at Olkiluoto 2004. Posiva Oy, Working Report 2005-17, 78 p.
Lahti, M., Tammenmaa, J. & Hassinen, P., 2001. Geophysical logging of boreholes OL- KR13 and OL-KR14 at Olkiluoto, Eurajoki 2001. Posiva Oy, Working Report 2001-30, 139 p. In Finnish with an English abstract.
Lahti, M., Tammenmaa, J. & Hassinen, P., 2003. Geophysical logging of boreholes OL- KR19, OL-KR19b, OL-KR20, OL-KR20b, OL-KR22, OL-KR22b and OL-KR8 continuation at Olkiluoto, Eurajoki 2002. Posiva Oy, Working Report 2003-05, 176 p.
Laurila, T. & Tammenmaa, J., 1996. Geophysical borehole loggings in Olkiluoto, Eurajoki, in 1996, borehole OL-KR10. Posiva Oy, Working Report PATU-96-14, 8p. In Finnish with an English abstract.
Lehtimäki, T., 2003a. Combined interpretation and processing of seismic refraction data at Olkiluoto. Posiva Oy, Working Report, 41 p. 322 APPENDIX II
Lehtimäki, T., 2003b. Supplementary interpretation of seismic refraction data at Olkiluoto. Posiva Oy, Working Report 2003-63, 42 p.
Lehtonen, T., Heikkinen E., 2004. Visualization and modeling of the year 2003 mise-a- la-masse survey data at Olkiluoto site. Posiva Oy, Working report 2004-51.
Lehtonen, T., 2006. Visualization and interpretation of the year 2004 mise-a-la-masse survey data at Olkiluoto site. Posiva Oy, Working report 2006-08, 118 p.
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Lindberg, A. & Paananen, M., 1991b. Petrographic and petrophysical studies on rock samples from LLW and MLW repository. TVO/VLJ final disposal, Working Report 90- 09, 12 p. In Finnish with an English abstract.
Lindberg, A. & Paananen, M., 1992. Petrography, lithogeochemistry and petrophysics of rock samples from Konginkangas, Sievi and Eurajoki study sites, southern and western Finland. Boreholes KI-KR7, SY-KR7 and OL-KR6. TVO/Site investigations, Working Report 92-34, 40 p. In Finnish with an English abstract.
Lowit, B, Morecroft, S. & Wild, P., 1996. Geophysical borehole loggings at Olkiluoto, Kivetty and Romuvaara sites, Finland 1996. Dual neutron and full waveform sonic log report. Posiva Oy, Working Report PATU-96-33e.
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Paananen, M. & Kurimo, M., 1990. Interpretation of geophysical airborne and ground survey data on the Olkiluoto study site. TVO/Site Investigations, Work Report 90-19, 41 p. In Finnish with an English abstract. 323 APPENDIX II
Paananen, M., Lehtimäki, J., Kurimo, M., Jokinen, T. & Soininen, H., 1991. Interpretation of electromagnetic and electric soundings at Olkiluoto study site, Eurajoki. TVO, Working Report 91-28, 37 p. In Finnish with an English abstract.
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Suomen Malmi Oy, 1990. Geophysical borehole loggings at Olkiluoto investigation site, boreholes KR4 and KR5. TVO/Site Investigations, Working Report 90-44, 9p. In Finnish with an English abstract.
Sutinen, H., 2002. GPR sounding for determination of bedrock fracturing on investigation trench TK3 at Olkiluoto. Posiva Oy, Working Report 2002-52, 45 p.
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1. PRELIMINARY FAULT ANALYSIS
In the following text we introduce the concepts and methodologies, which have been used in the analysis of faults’ evolution and kinematics. As an introduction, the first section outlines the basic methods of fault-slip data collection and correction, which provides the framework for the description of the properties of the faults observed in the ONKALO tunnel and outcrops, which is given in the second section. In the third section, a kinematic interpretation of the faults is given and all presented data is gathered into a preliminary synthesis of the brittle deformation at Olkiluoto.
1.1 Collection and correction of fault-slip data
The basic properties which characterise the kinematics of faults are fault plane orientation, slip direction and sense-of-movement, which define the so-called “fault-slip datum” (after Marret & Allmendinger 1990), which can then be further applied in fault- slip analysis. A basic problem which arises during the measurement of fault-slip data that the orientation of the fault plane is measured independently from the slip direction, which causes misfit within the fault-slip datum, i.e. measured slip directions are not located on the fault plane, but make an (acute) angle with it. This misfit arises due to the non-planar character of faults and the measurement of plane orientations and slip directions form slightly different locations of the fault plane. Commonly this misfit is eliminated by measuring a so-called “rake”, which is the angle between fault’s strike and slip directions, measured in the fault plane down from the strike direction. Yet, it is emphasized that by using this method, any measurement errors are inherently included in the fault-slip datum, without any possibility for later corrections. Therefore, in the Posiva Oy’s data acquisition programme, fault-slip datum is collected by measuring fault plane and slip direction orientations separately. The maximum allowed misfit is set to 20 degrees and any fault-slip datum with a misfit greater than this is omitted from any further analysis; misfits smaller than this are considered as feasible from the point of view of qualitative fault slip analysis. The slip directions are corrected by projecting them on to the fault plane through an auxiliary plane traversing through the normal of the fault plane and the measured slip direction, i.e. minimising the angular correction needed. In practice, the correction and analysis of the fault-slip data is done with TectonicsFP-program (Ortner et al. 2002). An example of a fault-slip datum and correction of misfit are presented in Figure 11 and Figure 2.
1 The diagram used for the plotting of fault-slip data is a so-called Angelier-plot, which is a lower hemisphere plot where the orientation of the fault plane is shown as a great circle and slip direction as a point. The sense-of-movement is shown by arrow, which indicates the direction of movement of the hanging-wall block. In the case of strike-slip faults, the sense-of-movement is indicated by double-tip arrow. 326 APPENDIX III
Figure 1. Stereogram showing the angular misfit between measured fault plane and slip direction.
Figure 2. Stereogram showing the method for correcting the misfit – the measured slip direction is projected to the fault plane by through an auxiliary plane traversing through the normal of the fault plane and the measured slip direction, minimising the angular correction needed. 327 APPENDIX III
As an example of the collection and correction of fault slip data, all fault-slip data existing in the Posiva fracture database and located within the zone of influence of OL- BFZ099 is collected (Table 1, Figure 3), resulting in a total of 192 fault-slip measurements from 13 drillholes, and corrected, i.e. the angular misfit between the fault plane orientation and the slip direction is handled before any further analysis. The corrected data is shown in Table 2 and Figure 4, with the fault-slip datum having a misfit greater than 20 degrees highlighted with light-blue colour. The corrected fault- slip data, from where the outliers having angular misfit greater than 20 degrees have been removed, is shown in Figure 5, and, in addition, the same data, with fault-slip datum with unknown sense-of-movement removed, is shown in Figure 6. This is the final input, which can then be applied for more detailed fault-slip analysis. In Figure 7, the distribution of angular misfits of the original data is shown as a histogram, together with cumulative curve. Approximately 80 percent of the measured fault-slip datum out of the entire fault-slip data set from OL-BFZ099 has a misfit less than 20 degrees, with a mean value of 11.4 degrees.
Table 1. Fault-slip data collected from brittle deformation zone OL- BFZ099
Fault plane Slip direction Sense Drillhole Fracture position (m) Dip direction Dip Azimuth Plunge 138 45 218 1 No data OL-KR1 492.44 155 57 70 2 No data OL-KR1 492.61 158 49 97 28 No data OL-KR1 512.13 304 33 234 15 No data OL-KR1 537.78 179 53 190 42 Normal OL-KR1 538.08 150 54 105 32 No data OL-KR1 541.06 140 50 207 6 No data OL-KR2 469.87 181 30 198 37 No data OL-KR2 471.65 123 35 200 14 No data OL-KR2 471.73 132 37 168 14 Dextral OL-KR3 464.8 36 62 135 11 Sinistral OL-KR3 471.07 62 33 134 12 Sinistral OL-KR3 471.23 179 46 154 30 Normal OL-KR3 471.8 155 60 120 24 No data OL-KR4 750.26 181 53 154 44 Sinistral OL-KR4 754.16 140 57 106 45 Sinistral OL-KR4 757.57 162 78 248 25 Dextral OL-KR4 760.48 218 58 94 10 Dextral OL-KR4 760.53 159 31 183 24 Sinistral OL-KR4 765.53 166 41 340 48 Sinistral OL-KR4 770.12 192 70 205 63 Dextral OL-KR4 774.82 161 64 168 55 Sinistral OL-KR4 775.43 168 61 155 63 Sinistral OL-KR4 776.37 161 21 148 24 Dextral OL-KR4 781.32 162 21 158 26 Dextral OL-KR4 786.74 98 62 181 6 Dextral OL-KR4 802.69 98 62 13 8 Sinistral OL-KR4 809.96 54 46 102 28 No data OL-KR4 812.92 28 40 42 40 Sinistral OL-KR4 813.05 112 51 19 8 Sinistral OL-KR4 814.85 106 38 145 39 No data OL-KR5 261.69 163 27 102 14 No data OL-KR5 269.5 328 APPENDIX III
193 17 98 3 No data OL-KR5 273.55 156 46 161 47 No data OL-KR5 300 141 51 176 34 No data OL-KR5 300.23 290 29 220 22 No data OL-KR6 104.29 278 52 340 18 No data OL-KR6 113.04 28 52 324 29 No data OL-KR6 126.19 182 51 224 37 No data OL-KR6 132.11 137 33 198 20 No data OL-KR6 135.15 172 62 214 43 No data OL-KR11 614.92 66 82 158 14 No data OL-KR11 640.23 196 56 119 15 No data OL-KR12 568.21 117 74 144 37 Sinistral OL-KR12 582.41 194 40 286 5 Dextral OL-KR13 445.77 146 25 98 34 Sinistral OL-KR13 446.51 72 28 156 16 Sinistral OL-KR13 451.04 169 26 125 36 Dextral OL-KR13 451.12 139 53 87 47 Sinistral OL-KR13 451.27 129 29 134 33 Reverse OL-KR13 451.48 96 29 112 38 Dextral OL-KR13 451.53 117 28 183 7 Dextral OL-KR13 451.58 118 38 139 6 Dextral OL-KR13 451.6 129 35 204 2 Sinistral OL-KR13 451.62 140 27 86 22 Dextral OL-KR13 451.67 143 30 56 3 Dextral OL-KR13 451.69 179 28 203 28 Sinistral OL-KR13 453.23 146 46 88 54 Dextral OL-KR13 453.28 165 52 99 36 Dextral OL-KR13 453.5 169 19 237 23 Sinistral OL-KR13 456 168 21 239 2 Sinistral OL-KR13 456.24 180 31 173 51 Normal OL-KR13 456.47 178 19 148 12 Sinistral OL-KR13 456.53 152 9 183 32 No data OL-KR13 457.16 203 33 205 16 Reverse OL-KR13 457.33 182 38 166 25 Reverse OL-KR13 457.35 133 25 174 24 Sinistral OL-KR13 458.05 130 25 128 41 Dextral OL-KR13 458.28 103 86 32 24 Dextral OL-KR13 458.89 161 28 167 21 Reverse OL-KR13 463.33 92 28 173 16 Sinistral OL-KR13 463.92 103 37 171 14 Sinistral OL-KR13 463.97 135 22 59 15 Dextral OL-KR13 464.04 154 28 191 26 Sinistral OL-KR13 464.41 80 50 22 30 Sinistral OL-KR13 465.08 183 49 186 43 Normal OL-KR13 467.92 52 53 125 19 Sinistral OL-KR13 475.11 49 62 111 25 No data OL-KR13 475.17 66 36 86 32 Reverse OL-KR13 475.7 316 3 258 1 Normal OL-KR13 476.07 102 81 179 17 Sinistral OL-KR13 479.61 332 32 274 12 Dextral OL-KR13 479.94 78 15 147 13 Sinistral OL-KR13 480.33 60 65 106 23 Sinistral OL-KR13 480.34 78 19 106 21 Reverse OL-KR13 485.96 168 63 104 33 Sinistral OL-KR13 496.5 52 62 109 32 Sinistral OL-KR13 496.72 329 APPENDIX III
148 11 205 37 Dextral OL-KR13 475.61 63 32 138 13 Sinistral OL-KR13 480.26 122 22 144 10 Reverse OL-KR13 483.56 130 56 47 25 No data OL-KR19 234.81 13 32 90 15 Dextral OL-KR19 241.37 5 65 55 22 Sinistral OL-KR19 254.03 158 42 217 28 Sinistral OL-KR19 257.32 241 18 215 20 No data OL-KR19 257.43 210 33 185 35 Reverse OL-KR19 258.87 210 11 188 18 No data OL-KR19 259.24 65 29 168 4 Dextral OL-KR20 449.63 97 27 181 7 Sinistral OL-KR20 449.9 89 44 139 11 No data OL-KR20 451.28 143 48 179 48 No data OL-KR20 452.64 143 52 109 75 Reverse OL-KR20 462.81 154 53 130 73 No data OL-KR20 463.88 153 24 116 45 Dextral OL-KR20 386.93 142 25 172 35 Sinistral OL-KR20 389.42 43 36 90 27 Dextral OL-KR20 389.8 72 82 155 20 Dextral OL-KR20 410.59 130 66 96 56 No data OL-KR20 411.84 159 21 94 32 No data OL-KR20 411.98 149 22 192 40 No data OL-KR20 412.02 149 32 196 43 No data OL-KR20 412.58 161 27 125 45 Sinistral OL-KR20 412.96 168 48 14 5 Normal OL-KR20 413.98 182 57 339 7 Sinistral OL-KR20 414.08 191 54 165 7 No data OL-KR20 414.09 201 39 166 10 Sinistral OL-KR20 414.2 146 18 195 20 Sinistral OL-KR20 415.4 116 24 33 5 Sinistral OL-KR20 416.47 163 31 41 28 Sinistral OL-KR20 416.7 166 35 169 34 Dextral OL-KR20 416.76 329 24 22 32 Dextral OL-KR20 416.86 262 54 350 4 Dextral OL-KR20 419.37 155 16 62 5 Sinistral OL-KR20 419.47 167 24 48 5 Sinistral OL-KR20 419.51 183 20 221 5 Sinistral OL-KR20 419.64 100 30 27 15 Sinistral OL-KR20 420.71 184 29 44 37 Sinistral OL-KR20 421.02 182 33 240 4 Sinistral OL-KR20 421.19 190 36 71 25 Sinistral OL-KR20 421.22 147 21 209 15 Sinistral OL-KR20 422.86 148 14 51 7 No data OL-KR20 430.22 167 52 136 47 No data OL-KR20 436.19 65 29 168 4 Dextral OL-KR20 449.63 97 27 181 7 Sinistral OL-KR20 449.9 120 43 102 62 No data OL-KR20 455.38 67 74 149 41 Dextral OL-KR20 476.02 140 31 175 55 Sinistral OL-KR20 483.14 88 30 66 30 Sinistral OL-KR20 487.56 90 33 123 60 No data OL-KR20 487.58 170 14 126 36 Dextral OL-KR20 390.54 168 9 180 15 Normal OL-KR20 391.45 105 34 22 6 Dextral OL-KR20 412.72 330 APPENDIX III
84 73 171 12 Dextral OL-KR20 413.16 175 23 219 17 Sinistral OL-KR20 418.28 116 21 75 25 Dextral OL-KR20 418.32 124 49 72 72 No data OL-KR20 418.74 133 38 54 15 Sinistral OL-KR20 419.06 127 35 69 25 Sinistral OL-KR20 419.27 162 21 142 49 Sinistral OL-KR20 423.77 104 18 195 4 Sinistral OL-KR20 423.83 131 76 45 26 Sinistral OL-KR20 424.45 131 82 273 88 No data OL-KR20 437.46 89 44 139 11 No data OL-KR20 451.28 143 48 179 48 No data OL-KR20 452.64 143 52 109 75 Reverse OL-KR20 462.81 154 53 130 73 No data OL-KR20 463.88 72 64 127 20 No data OL-KR29 743.33 154 21 145 25 No data OL-KR29 746.41 155 23 171 30 Normal OL-KR29 746.52 172 61 97 23 Dextral OL-KR29 756.4 330 16 340 10 Normal OL-KR29 746.1 230 10 184 13 Dextral OL-KR29 785.47 155 50 172 62 Sinistral OL-KR29 785.92 180 34 86 5 Sinistral OL-KR33 272.7 112 46 168 34 No data OL-KR33 276.09 194 44 170 35 Sinistral OL-KR33 277.01 174 68 200 67 Sinistral OL-KR33 278.63 79 31 196 20 Dextral OL-KR33 278.66 102 63 211 15 Sinistral OL-KR33 278.77 125 46 100 74 Sinistral OL-KR33 279.18 229 73 216 11 Sinistral OL-KR33 279.24 122 57 209 8 Sinistral OL-KR33 279.3 94 49 225 10 Sinistral OL-KR33 279.54 186 58 232 36 Sinistral OL-KR33 279.95 29 55 323 29 Dextral OL-KR33 280.12 105 36 34 15 Sinistral OL-KR33 280.6 96 39 30 13 Sinistral OL-KR33 280.67 172 46 181 46 No data OL-KR33 281.27 18 21 178 8 Normal OL-KR33 281.87 313 88 29 59 Sinistral OL-KR33 282.19 121 30 199 2 Sinistral OL-KR33 282.25 93 41 18 15 Sinistral OL-KR33 282.78 103 71 171 40 Sinistral OL-KR33 287.18 115 64 152 31 Sinistral OL-KR33 287.21 80 66 129 39 Sinistral OL-KR33 287.27 67 39 115 15 Dextral OL-KR33 287.46 133 45 154 45 Normal OL-KR33 287.53 108 60 182 49 Sinistral OL-KR33 287.83 112 68 188 25 Sinistral OL-KR33 287.85 90 28 146 28 Sinistral OL-KR33 288.7 184 47 115 35 Dextral OL-KR33 288.85 129 36 72 30 Dextral OL-KR33 301.61 331 APPENDIX III
Table 2. Corrected fault-slip data from OL-BFZ099. Fault-slip datums with angular misfit greater than 20 degrees are highlighted with blue colour.
Fault plane Corrected slip Measured slip Corrected Misfit Drillhole Fracture position direction direction sense (m)
Dip direction Dip Azimuth Plunge Azimuth Plunge 138 45 222.46 5.52 218 1 No data 6.3 OL-KR1 492.44 155 57 67.4 3.69 70 2 No data 3.1 OL-KR1 492.61 158 49 96.35 28.65 97 28 No data 0.9 OL-KR1 512.13 304 33 235.12 13.17 234 15 No data 2.1 OL-KR1 537.78 179 53 192.61 52.21 190 42 Normal 10.4 OL-KR1 538.08 150 54 97.44 39.92 105 32 No data 10 OL-KR1 541.06 140 50 216.96 15.05 207 6 No data 13.3 OL-KR2 469.87 181 30 196.65 29.07 198 37 No data 8 OL-KR2 471.65 123 35 197.62 10.52 200 14 No data 4.2 OL-KR2 471.73 132 37 174.75 28.96 168 14 Normal 16.2 OL-KR3 464.8 36 62 123.33 5.01 135 11 Sinistral 13 OL-KR3 471.07 62 33 133.7 11.52 134 12 Reverse 0.6 OL-KR3 471.23 179 46 148.79 41.83 154 30 Normal 12.5 OL-KR3 471.8 155 60 99.73 44.62 120 24 No data 26.4 OL-KR4 750.26 181 53 151.02 48.98 154 44 Normal 5.4 OL-KR4 754.16 140 57 101.49 50.31 106 45 Normal 6.1 OL-KR4 757.57 162 78 246.4 24.67 248 25 Normal 1.5 OL-KR4 760.48 218 58 302.64 8.5 94 10 Dextral 34 OL-KR4 760.53 159 31 184.11 28.55 183 24 Reverse 4.7 OL-KR4 765.53 166 41 85 7.75 340 48 Sinistral 85.9 OL-KR4 770.12 192 70 208.81 69.18 205 63 Normal 6.4 OL-KR4 774.82 161 64 170.19 63.71 168 55 Reverse 8.8 OL-KR4 775.43 168 61 156.03 60.46 155 63 Normal 2.6 OL-KR4 776.37 161 21 148.3 20.53 148 24 Reverse 3.5 OL-KR4 781.32 162 21 158.14 20.96 158 26 Reverse 5 OL-KR4 786.74 98 62 183.94 7.58 181 6 Dextral 3.3 OL-KR4 802.69 98 62 12.45 8.3 13 8 Sinistral 0.6 OL-KR4 809.96 54 46 105.62 32.74 102 28 No data 5.7 OL-KR4 812.92 28 40 41.83 39.17 42 40 Reverse 0.8 OL-KR4 813.05 112 51 24.75 3.39 19 8 Sinistral 7.3 OL-KR4 814.85 106 38 141.71 32.39 145 39 No data 7.1 OL-KR5 261.69 163 27 102.05 13.9 102 14 No data 0.1 OL-KR5 269.5 193 17 279.26 1.14 98 3 No data 4.3 OL-KR5 273.55 156 46 160.9 45.9 161 47 No data 1.1 OL-KR5 300 141 51 182.24 42.88 176 34 No data 10.1 OL-KR5 300.23 290 29 224.74 13.06 220 22 No data 10 OL-KR6 104.29 278 52 347.19 24.45 340 18 No data 9.3 OL-KR6 113.04 28 52 323.83 29.15 324 29 No data 0.2 OL-KR6 126.19 182 51 227.27 40.99 224 37 No data 4.7 OL-KR6 132.11 137 33 196.89 18.05 198 20 No data 2.2 OL-KR6 135.15 172 62 222.56 50.07 214 43 No data 9.2 OL-KR11 614.92 66 82 154.07 13.48 158 14 No data 3.9 OL-KR11 640.23 196 56 117.29 16.19 119 15 No data 2 OL-KR12 568.21 117 74 176.51 60.53 144 37 Reverse 31.2 OL-KR12 582.41 194 40 282.7 1.09 286 5 Dextral 5.1 OL-KR13 445.77 146 25 103.39 18.94 98 34 Normal 15.8 OL-KR13 446.51 72 28 150.61 5.99 156 16 Reverse 11.3 OL-KR13 451.04 169 26 130.31 20.84 125 36 Reverse 15.9 OL-KR13 451.12 139 53 92.14 42.22 87 47 Normal 6 OL-KR13 451.27 332 APPENDIX III
129 29 133.8 28.91 134 33 Reverse 4.1 OL-KR13 451.48 96 29 110.49 28.22 112 38 Normal 9.9 OL-KR13 451.53 117 28 185.06 11.24 183 7 Normal 4.7 OL-KR13 451.58 118 38 147.61 34.19 139 6 Normal 29.3 OL-KR13 451.6 129 35 207.87 7.7 204 2 Reverse 6.9 OL-KR13 451.62 140 27 87.91 17.38 86 22 Reverse 5 OL-KR13 451.67 143 30 56.55 2.05 56 3 Reverse 1.1 OL-KR13 451.69 179 28 202.56 25.98 203 28 Reverse 2.1 OL-KR13 453.23 146 46 104.05 37.6 88 54 Reverse 19.8 OL-KR13 453.28 165 52 104.01 31.83 99 36 Reverse 5.9 OL-KR13 453.5 169 19 232.34 8.78 237 23 Reverse 14.9 OL-KR13 456 168 21 240.65 6.53 239 2 Reverse 4.8 OL-KR13 456.24 180 31 174.54 30.88 173 51 Normal 20.1 OL-KR13 456.47 178 19 147.23 16.48 148 12 Normal 4.5 OL-KR13 456.53 152 9 180.91 7.89 183 32 No data 24.2 OL-KR13 457.16 203 33 205.4 32.98 205 16 Reverse 17 OL-KR13 457.33 182 38 163.49 36.53 166 25 Reverse 11.7 OL-KR13 457.35 133 25 172.69 19.74 174 24 Reverse 4.4 OL-KR13 458.05 130 25 128.27 24.99 128 41 Reverse 16 OL-KR13 458.28 103 86 14.97 26.21 32 24 Reverse 15.6 OL-KR13 458.89 161 28 167.38 27.85 167 21 Reverse 6.9 OL-KR13 463.33 92 28 168.3 7.18 173 16 Reverse 9.9 OL-KR13 463.92 103 37 171.85 15.21 171 14 Reverse 1.5 OL-KR13 463.97 135 22 62.24 6.83 59 15 Reverse 8.8 OL-KR13 464.04 154 28 190.12 23.24 191 26 Reverse 2.9 OL-KR13 464.41 80 50 20.69 31.31 22 30 Normal 1.7 OL-KR13 465.08 183 49 186.36 48.95 186 43 Normal 6 OL-KR13 467.92 52 53 126.16 19.91 125 19 Reverse 1.4 OL-KR13 475.11 49 62 120.42 30.93 111 25 No data 10.2 OL-KR13 475.17 66 36 86.55 34.23 86 32 Reverse 2.3 OL-KR13 475.7 316 3 257.97 1.59 258 1 Normal 0.6 OL-KR13 476.07 102 81 188.9 18.84 179 17 Sinistral 9.6 OL-KR13 479.61 332 32 271.34 17.02 274 12 Reverse 5.6 OL-KR13 479.94 78 15 145.22 5.92 147 13 Reverse 7.3 OL-KR13 480.33 60 65 128.27 38.44 106 23 Reverse 24.5 OL-KR13 480.34 78 19 105.35 17.01 106 21 Reverse 4 OL-KR13 485.96 168 63 99.44 35.66 104 33 Normal 4.6 OL-KR13 496.5 52 62 117.68 37.76 109 32 Reverse 9.2 OL-KR13 496.72 148 11 199.55 6.89 205 37 Normal 30.5 OL-KR13 475.61 63 32 136.29 10.18 138 13 Reverse 3.3 OL-KR13 480.26 122 22 145.58 20.32 144 10 Reverse 10.4 OL-KR13 483.56 130 56 54.37 20.2 47 25 No data 8.3 OL-KR19 234.81 13 32 86.85 9.86 90 15 Normal 6 OL-KR19 241.37 5 65 75.61 35.44 55 22 Reverse 22.4 OL-KR19 254.03 158 42 215.37 25.9 217 28 Reverse 2.6 OL-KR19 257.32 241 18 215.52 16.35 215 20 No data 3.7 OL-KR19 257.43 210 33 186.18 30.71 185 35 Reverse 4.4 OL-KR19 258.87 210 11 188.57 10.26 188 18 No data 7.8 OL-KR19 259.24 65 29 343.32 4.58 168 4 Reverse 9.8 OL-KR20 449.63 97 27 179.4 3.85 181 7 Reverse 3.5 OL-KR20 449.9 89 44 149.71 25.29 139 11 No data 17.5 OL-KR20 451.28 143 48 175.73 43.05 179 48 No data 5.4 OL-KR20 452.64 143 52 128.26 51.07 109 75 Reverse 25.2 OL-KR20 462.81 154 53 141.94 52.38 130 73 No data 21.2 OL-KR20 463.88 153 24 122.9 21.07 116 45 Reverse 24.6 OL-KR20 386.93 333 APPENDIX III
142 25 169.04 22.55 172 35 Reverse 12.7 OL-KR20 389.42 43 36 89.72 26.48 90 27 Normal 0.6 OL-KR20 389.8 72 82 158.97 20.61 155 20 Dextral 3.8 OL-KR20 410.59 130 66 90.9 60.16 96 56 No data 5 OL-KR20 411.84 159 21 101.5 11.65 94 32 No data 21.5 OL-KR20 411.98 149 22 185.54 17.98 192 40 No data 22.7 OL-KR20 412.02 149 32 187.8 25.96 196 43 No data 18.3 OL-KR20 412.58 161 27 131.69 23.95 125 45 Normal 21.7 OL-KR20 412.96 168 48 218.69 35.13 14 5 Reverse 46.4 OL-KR20 413.98 182 57 121.04 36.78 339 7 Normal 56.4 OL-KR20 414.08 191 54 141.08 41.55 165 7 No data 40.5 OL-KR20 414.09 201 39 156.37 29.95 166 10 Normal 21.9 OL-KR20 414.2 146 18 193.14 12.46 195 20 Reverse 7.7 OL-KR20 415.4 116 24 33.7 3.41 33 5 Normal 1.7 OL-KR20 416.47 163 31 242.67 6.15 41 28 Reverse 40 OL-KR20 416.7 166 35 169.04 34.96 169 34 Normal 1 OL-KR20 416.76 329 24 16.4 16.77 22 32 Normal 16.1 OL-KR20 416.86 262 54 349.4 3.57 350 4 Dextral 0.7 OL-KR20 419.37 155 16 243.56 0.41 62 5 Reverse 5.6 OL-KR20 419.47 167 24 233.95 9.89 48 5 Reverse 16 OL-KR20 419.51 183 20 223.38 15.5 221 5 Reverse 10.8 OL-KR20 419.64 100 30 29.32 10.81 27 15 Normal 4.8 OL-KR20 420.71 184 29 251.48 11.98 44 37 Reverse 55.4 OL-KR20 421.02 182 33 246.49 15.62 240 4 Reverse 13.3 OL-KR20 421.19 190 36 273.76 4.51 71 25 Sinistral 36.9 OL-KR20 421.22 147 21 207.54 10.69 209 15 Reverse 4.5 OL-KR20 422.86 148 14 233.05 1.23 51 7 No data 8.5 OL-KR20 430.22 167 52 135.64 47.54 136 47 No data 0.6 OL-KR20 436.19 65 29 343.32 4.58 168 4 Reverse 9.8 OL-KR20 449.63 97 27 179.4 3.85 181 7 Reverse 3.5 OL-KR20 449.9 120 43 107.94 42.36 102 62 No data 20 OL-KR20 455.38 67 74 143.33 39.5 149 41 Normal 4.6 OL-KR20 476.02 140 31 164.96 28.58 175 55 Reverse 27.4 OL-KR20 483.14 88 30 66.38 28.22 66 30 Normal 1.8 OL-KR20 487.56 90 33 111.52 31.14 123 60 No data 29.9 OL-KR20 487.58 170 14 130.67 10.92 126 36 Reverse 25.4 OL-KR20 390.54 168 9 179.8 8.81 180 15 Normal 6.2 OL-KR20 391.45 105 34 22.6 5.1 22 6 Reverse 1.1 OL-KR20 412.72 84 73 170.34 11.8 171 12 Dextral 0.7 OL-KR20 413.16 175 23 218.99 16.98 219 17 Reverse 0 OL-KR20 418.28 116 21 77.13 16.64 75 25 Reverse 8.6 OL-KR20 418.32 124 49 100.23 46.47 72 72 No data 28.7 OL-KR20 418.74 133 38 57.2 10.85 54 15 Sinistral 5.2 OL-KR20 419.06 127 35 71.12 21.44 69 25 Normal 4.1 OL-KR20 419.27 162 21 146.14 20.27 142 49 Normal 28.9 OL-KR20 423.77 104 18 193.73 0.09 195 4 Reverse 4.1 OL-KR20 423.83 131 76 47.78 25.33 45 26 Normal 2.6 OL-KR20 424.45 131 82 139.9 81.9 273 88 No data 9.6 OL-KR20 437.46 89 44 149.71 25.29 139 11 No data 17.5 OL-KR20 451.28 143 48 175.73 43.05 179 48 No data 5.4 OL-KR20 452.64 143 52 128.26 51.07 109 75 Reverse 25.2 OL-KR20 462.81 154 53 141.94 52.38 130 73 No data 21.2 OL-KR20 463.88 72 64 144.8 31.23 127 20 No data 19.5 OL-KR29 743.33 154 21 145.25 20.78 145 25 No data 4.2 OL-KR29 746.41 155 23 170.09 22.29 171 30 Normal 7.8 OL-KR29 746.52 334 APPENDIX III
172 61 96 23.58 97 23 Reverse 1.1 OL-KR29 756.4 330 16 340.29 15.76 340 10 Normal 5.8 OL-KR29 746.1 230 10 184.75 7.08 184 13 Reverse 6 OL-KR29 785.47 155 50 167.48 49.32 172 62 Reverse 12.9 OL-KR29 785.92 180 34 269.58 0.29 86 5 Reverse 6.4 OL-KR33 272.7 112 46 165.79 31.45 168 34 No data 3.2 OL-KR33 276.09 194 44 167.69 40.88 170 35 Normal 6.2 OL-KR33 277.01 174 68 198.9 65.99 200 67 Reverse 1.1 OL-KR33 278.63 79 31 359.98 6.53 196 20 Reverse 30.9 OL-KR33 278.66 102 63 189.5 4.89 211 15 Sinistral 23.4 OL-KR33 278.77 125 46 114.03 45.47 100 74 Normal 29.2 OL-KR33 279.18 229 73 170.46 59.64 216 11 Normal 59.2 OL-KR33 279.24 122 57 207.44 6.99 209 8 Sinistral 1.9 OL-KR33 279.3 94 49 18.49 16.06 225 10 Normal 37 OL-KR33 279.54 186 58 240.06 43.21 232 36 Reverse 9.5 OL-KR33 279.95 29 55 322.34 29.5 323 29 Reverse 0.8 OL-KR33 280.12 105 36 34.81 13.83 34 15 Normal 1.4 OL-KR33 280.6 96 39 27.43 16.48 30 13 Normal 4.3 OL-KR33 280.67 172 46 180.94 45.65 181 46 No data 0.4 OL-KR33 281.27 18 21 354.1 19.34 178 8 Reverse 27.6 OL-KR33 281.87 313 88 39.56 59.81 29 59 Reverse 5.4 OL-KR33 282.19 121 30 201.08 5.68 199 2 Reverse 4.2 OL-KR33 282.25 93 41 19.17 13.61 18 15 Normal 1.8 OL-KR33 282.78 103 71 175.18 41.63 171 40 Reverse 3.6 OL-KR33 287.18 115 64 172.04 48.12 152 31 Reverse 22.9 OL-KR33 287.21 80 66 141.52 46.96 129 39 Reverse 12.1 OL-KR33 287.27 67 39 121.24 25.32 115 15 Normal 11.9 OL-KR33 287.46 133 45 153.34 43.16 154 45 Normal 1.9 OL-KR33 287.53 108 60 167.46 41.35 182 49 Reverse 12.8 OL-KR33 287.83 112 68 190.58 26.1 188 25 Reverse 2.6 OL-KR33 287.85 90 28 141.63 18.27 146 28 Reverse 10.5 OL-KR33 288.7 184 47 122.93 27.42 115 35 Reverse 10.2 OL-KR33 288.85 129 36 75.96 23.6 72 30 Reverse 7.3 OL-KR33 301.61 335 APPENDIX III
BFZ099 original data Datasets: 192
Figure 3. Original fault-slip data collected from OL-BFZ099, shown as an Angelier- plot. Equal-area, lower hemisphere projection. See also Table 1.
BFZ099 corrected data Datasets: 192
Figure 4. Corrected fault-slip data from OL-BFZ099, shown as an Angelier-plot. Equal-area, lower hemisphere projection. 336 APPENDIX III
BFZ099 outliers removed Datasets: 155
Figure 5. Corrected fault-slip data from OL-BFZ099, with fault-slip datum with angular misfits greater than 20 degrees removed. Equal-area, lower hemisphere projection.
Datasets: 115
Figure 6. Corrected fault-slip data from OL-BFZ099, with fault-slip datum with unknown sense-of-movement and angular misfits greater than 20 degrees removed. Equal-area, lower hemisphere projection. 337 APPENDIX III
Figure 7. Distribution of angular misfits of the fault-slip data from OL-BFZ099.
1.2 Methods of fault-slip analysis
Fault-slip analysis aims in the reconstruction of paleostress orientations from the fault- slip data and is based on the assumptions that slip direction is parallel to the maximum shear stress (Wallace-Bott hypothesis), stress is homogenously distributed and faults do not exert mechanical interaction on each other, i.e. faults have slipped independently on a same stress state (e.g. Ramsay & Lisle 2000). Based on these assumptions, different fault analysis methods may be applied and these are described in the following text.
The fault-slip data presented in the preceding Section can be further applied in the analysis of faults by the use of so called P-T-method, which is based on the graphical identification of kinematic shortening (P) and extension (T) axis for each fault-slip datum (Marret & Allmendinger 1990). In the method it is assumed that both the shortening (P) and extension axis (T) are located in the plane defined by the slip direction and the normal of the fault plane, at an angle of 45º with these poles; the mutual orientations of the shortening and extension axes is defined by the sense-of-slip of the fault (Figure 8). If the sense of slip is reversed, then the mutual locations of the shortening and extension axis are respectively switched. As stated by Marret & Allmendinger (1990), this method of presenting the kinematic axes is just and alternative representation of the original fault-slip data, requiring no interpretation, and can thus be used for both neoformed and reactivated faults, providing important constraints for subdividing faults further into kinematically compatible groups. By contouring of the kinematic axis for a larger number of kinematically compatible faults, it possible to characterize the orientations of average principal axes of incremental strain tensor (Marret & Allmendinger 1990), which, finally, may be interpreted to represent the average orientations of principal stress axis. 338 APPENDIX III
The association of fault-slip datum and graphically determined kinematic axis can also be presented as a right dihedra presentation (also known as fault plane solution) (cf. Angelier & Mechler 1979, Angelier 1994, Marret & Allmendinger 1990, Ramsay & Lisle 2000), in which the lower hemisphere projection is divided into compressive and extensional quadrants by the use of two orthogonal planes, the fault plane and a plane perpendicular to the slip direction (Figure 9). The nature of each quadrant is determined by the respective orientation of the shortening and extension axis (shortening axis is located on the compressive quadrant and extension axis on the tensile quadrant). The fault plane solution provides a more realistic approach for the determination of compression and extension directions than the specifically determined kinematic axes, as it gives “ranges” for the feasible orientations of the shortening and extension axes and the locations of the principal stress directions, which, may deviate from each other as the orientation of the principal stress directions is dependant on the value of ș, whereas the kinematic axes are set to be oriented 45 degrees from the fault plane. For faults formed in a same stress regime, the principal kinematic and stress axis must locate in the corresponding dihedra, and as a consequence, by superimposing the right dihedra presentations of multiple fault-slip datums, it possible to reduce the size of dihedral fields, where the average principal P-, T- and stress axis are located (See Figure 10). This is the called the right-dihedra method of fault analysis (Angelier & Mechler 1979; see also Angelier 1994, Marret & Allmendinger 1990, Ramsay & Lisle 2000).
Figure 8. An example on the identification of kinematic shortening (P) and extension (T) axis for a fault-slip datum. The kinematic axis, the pole to the fault plane and the slip direction are located in a common auxiliary plane, at an angle of 45 degrees to the slip direction and pole to the fault plane. The mutual locations of the kinematic axis are determined by the sense-of-movement of the fault plane. 339 APPENDIX III
Figure 9. A right-dihedra presentation (fault plane solution) constructed for the fault- slip datum presented in Figure 8; the dihedral representation is assembled by using the fault plane and a plane perpendicular to the slip direction. The nature of each quadrant is determined by the respective orientation of the shortening and extension axis. The grey colour corresponds to compressive quadrant and white colour to tensile quadrant.
Figure 10. The exemplification of the right-dihedra method: when the dihedral presentations of two faults are superimposed, the sizes of the compressive and tensile quadrants are effectively reduced, similarly to the feasible orientation of the kinematic axis and the stress axis (shown by dark grey and white colour). By the application of even larger set of faults, the feasible locations can be even further reduced. 340 APPENDIX III
By constructing the shortening and extension axis from a certain data set for each fault slip datum, it is possible to subdivide the data into kinematically compatible subgroups based on the orientations of the kinematic axes. As the construction of the kinematic axis graphically is quite time consuming for large data sets, in practice the work is done by using the structural analysis program TectonicsFP (Ortner et al. 2002). As an example, the kinematic axis for fault-slip data from OL-BFZ099 is shown in Figure 11, the shortening (P) axis shown as black circles and extension (T) axis as grey triangles. By manually selecting similar P- and T-axis combinations, the data set can be subdivided into subgroups with compatible shortening and extension axis (Figure 12), corresponding to faults formed or reactivated in similar stress fields. The clustering of the kinematic axis can be deduced to represent the possible directions of compression and extension, which are easily visualised by the use of the right-dihedra presentation (fault plane solution) (Figure 12).
The right-dihedra method can be applied to determine the feasible locations of the principal stress axis by superimposing the right dihedra of individual faults, although as the superimposition of the individual right dihedras is time consuming for large data sets, the procedure is carried out by computer-based grid search in which the compressive and tensile quadrants are calculated for each fault plane and each counting point in a 20-ring grid is assigned a value of 1 if located inside of a compressive quadrant. Finally, all counting points are superimposed and contoured and for all counting points eigenvectors and eigenvalues are calculated to receive the 3 principal stress axes (Ortner et al 2002). This is demonstrated for the kinematical subgroups from OL-BFZ099 in Figure 13.
BFZ099 Datasets: 115 P-Axes B-Axes T-Axes
Figure 11. P- and T-axis constructed for OL-BFZ099. 341 APPENDIX III
Figure 12. Kinematical subgroups from the fault slip data from OL-BFZ099. Shortening axes (black circles) and extension axes (grey triangles) are superimposed on the fault plane solutions, and nature of the respective quadrants are determined by the location of kinematic axis. The grey colour on the fault plane solution corresponds to compressive quadrant and the white to tensile quadrant.
Figure 13. Grid-search based results for right-dihedra analysis of the kinematical subgroups from OL-BFZ099. ı1 and ı3 are presented as a red circle and blue triangle, respectively.
1.3 Properties of faults at Olkiluoto
1.3.1 Macroscopic properties
The faults directly observable at Olkiluoto can be classified into three descriptive types, based on their geometry, kinematics and relation to existing ductile fabric:
x Low-angle reverse faults crosscutting and deflecting the foliation, dipping approximately to SE. Often these faults are closely associated with the occurrence of K-feldspar porphyry.
x Low- to medium-angle faults parallel to the foliation.
x Vertical to sub vertical strike-slip faults crosscutting the foliation and striking NE-SW. These faults are mainly sinistral, although indications of dextral movement also exist. On some occasions these faults are associated with K- feldspar porphyry. 342 APPENDIX III
An example of the first descriptive fault type is the brittle fault zone intersection ONK- BFI-7000-7190 (Figure 14), located at the chainage of 70 metres at the ONKALO tunnel, which is gently dipping zone composed of a few decimetre thick core section containing fault breccia and gouge composed of greenish clay (illite). In addition, the zone shows a strong deflection of the foliation towards the core of the fault (Figure 14), indicating reverse movement, which is currently associated with D4 thrusting and estimated to have an approximate age of 1830 Ma (ductile to ductile-brittle transition). The zone also has a “rim” of K-feldspar porphyry, with an approximate width of 1 metre in the footwall and 20 cm to 2 m in the hanging wall. The contact of the K- feldspar porphyry with the surrounding veined gneiss is gradational.
A similar low-angle zone, although of less pronounced character, has also been observed at the chainage of 1150 m of the ONKALO tunnel, again indicating reverse movement at the ductile to ductile-brittle D4 phase, characterised by deflected foliation (Figure 15). This fault also has a small rim of K-feldspar porphyry.
Figure 14. Brittle fault zone intersection ONK-BFI-7000-7190 at the ONKALO tunnel chainage of 70 metres. View is approximately towards south. 343 APPENDIX III
Figure 15. Brittle fault zone intersection ONK-BFI-115930-115980 at the ONKALO tunnel chainage of 1150 metres. View is approximately towards south.
An example of the second descriptive type of fault is shown in Figure 16, which is a low-angle fault zone intersection (ONK-BFI-93190-96300), coinciding with a high- grade ductile shear zone intersection and being parallel to the foliation. The core of the zone contains 3 to 40 cm thick fillings of chlorite, clay, pyrite, calcite, graphite, and kaolinite and in the thickest part of the zone the core contains fault breccia and thick clay fillings. The dip of the zone is towards N. 344 APPENDIX III
Figure 16. Low-angle fault zone intersection ONK-BFI-93190-96300, Picture taken from the left wall of the tunnel, at chainage 955. View is approximately towards S.
The best and most well investigated example of the strike-slip faults is the so-called “storage hall fault” (Mattila et al. 2007), shown in Figure 17 and
Figure 18; the fault has been observed in the investigation trench OL-TK11 and in five different locations in the tunnel, at chainages 130 m, 520 m, 900 m, 1500 m and 1700 m. The fault is a neoformed, sinistral strike-slip fault, with a well-developed damage zone, characterised by Riedel-fractures and a core containing fault breccia and gouge. The slip direction of the fault has an approximate plunge/trend of 18º/024º. In investigation trench OL-TK11, the fault is also associated with a rim of K-feldspar porphyry, similarly to the low-angle zones described in the preceding text; in addition, the zone seems to deflect older high-grade shear zones and these observations may indicate formation at the transition from ductile to brittle regime or reactivation of older ductile shear zones.
At the construction site of the new nuclear power plant (OL3) in the SW-part of Olkiluoto, A subvertical NNE-trending strike-slip fault was met, which crosscuts NW- dipping (40-50 degrees) diabase dike, providing evidence of the relative age of the strike-slip faults. Based on the observation, the strike-slip fault is evidently younger than the diabase dikes, i.e. 1560 Ma (see Mertanen et al. 2007). A map of the relationship between the fault and the diabase is shown in Figure 19A and a photograph in Figure 19B and Figure 19C. The crosscutting fault consists of two conjugate faults, the easternmost (Figure 19B) being dextral and having a dip of 89/264 and the westernmost (Figure 19C) sinistral with a dip of 80/102. Based on this information, it is possible to estimate the slip direction for both of the fault planes as for conjugate faults the slip direction must reside on the fault plane and 90 degrees from the line of intersection of the two faults. This procedure is shown in Figure 20 and the results 345 APPENDIX III indicate strong strike-slip component for the faults, with the slip direction plunging from NNW to NNE, with a plunge of approximately 30 degrees, which is consistent with the observations of strike-slip faults from other locations at Olkiluoto (see later Sections). According to the observations of the westernmost fault plane, it crosscut a pegmatite vein with an apparently sinistral offset of 45 cm and in addition had an observable trace length of approximately 200 metres.
Figure 17. The sinistral strike-slip fault, the so-called storage hall fault, observed in investigation trench OL-TK11. Figure from Mattila et al. (2007). 346 APPENDIX III
Figure 18. ONK-BFI-52150-52300 (the “storage hall fault”). Picture taken from the left wall of the tunnel at chainage 522 metres 347 APPENDIX III
A
B 348 APPENDIX III
C
Figure 19. An example of observed crosscutting relationship between strike-slip faults and Subjotnian (1560 Ma) diabase dike at the construction site of the new nuclear power plant, SW Olkiluoto. In (A) the geometry of the faults and the diabase are shown in 2D and in (B) and (C) the crosscutting relationship of the easternmost and westernmost fault planes with the diabase dike are shown. Photos by Jon Engström, Geological Survey of Finland. Dashed red lines indicate the traces of the fault planes.
AB
Figure 20. Determination of the slip direction for both of the fault planes by assuming that for conjugate faults the slip direction must lie on the fault planes, 90 degrees from the line of intersection. (A) Determination of the line of intersection, (B) determination of the slip direction for both fault planes. 349 APPENDIX III
1.3.2 Kinematic properties
In addition to the fault zone descriptions given above, fault-slip data from observed faults has been collected from the ONKALO tunnel, VLJ-tunnel2 and drillholes and a kinematic description of the faults, based on the data and the known properties of the faults is given in the following text. The interpretation is quite straightforward for the data gathered from the tunnels, where the properties of the faults can be quite accurately determined, yet, when applying fault-slip data from the drillholes, it is assumed that the fault-slip data extracted from the drillhole sections defined by the margins of a modelled fault zone is characteristic for that specific zone, and can thus be used for a more detailed analysis of the zone’s kinematic history. This assumption is of course heavily dependant on the “correctness” of the actual model itself, i.e. the definition of the location and orientation of the zone and the size of the zone of influence; nevertheless, this topic that is not treated here in any more detail, and the given assumption is considered as valid for further fault-slip analysis.
ONKALO-tunnel
Corrected fault-slip data from the ONKALO-access tunnel is shown in Figure 21, the total number of accepted fault-slip measurements being 53. Based on the geometry and kinematics, the faults can be subdivided into four groups, each characterised by typical slip directions and types of faults. The most prominent fault type is sinistral strike-slip fault (group A), which have a corresponding geometry to the “storage hall fault” described in Mattila et al. (2006), with associated synthetic and antithetic Riedel- fractures, the main fault orientation striking NE-SW. As the “Storage hall fault” is a neoformed fault and located just on the top of the ONKALO access tunnel, it is also plausible to explain the observations of the strike-slip faults in the ONKALO tunnel to be the product of the same deformation, i.e. they are controlled by sinistral strike-slip faulting regime. In addition, there are also dextral strike-slip faults (Group B), which, based on their orientation, correspond to the NE-SW trending faults in Group A. This may indicate tectonic inversion from the sinistral strike-slip regime to a dextral regime. Group faults correspond to faulting in NW-SE compression and Group B faulting in NE-SW compression.
In addition to the strike-slip faults, low-angle thrust faults are also a typical fault type (Group C), corresponding to the macroscopic descriptions given for the low-angle faults in the preceding text; the associated deflection of the foliation, the low-angle of the faults and the measured slip-directions, which are mainly of dip-slip type, indicate neoformed thrust faulting at Olkiluoto at the early phase of brittle tectonics, in E-W compression.
Both the strike-slip and thrust faults described above may also have been reactivated in an extensional regime, as indicated by the slip directions shown in the last subgroup (D) in Figure 21, although the slip directions are too heterogeneous and few for any detailed analysis.
2 Repository for low- and intermediate radioactive waste, which is located in NW part of Olkiluoto 350 APPENDIX III
Figure 21. Kinematic division of the faults in ONKALO access tunnel into subgroups. The first row shows the bulk properties of the faults as an Angelier-plot
VLJ-tunnel
Corrected fault-slip data from the VLJ-tunnel is shown in Figure 22 the total number of accepted fault-slip measurements being 51. The faults can be subdivided into five groups, each characterised by similar kinematic axis. The most prominent type of faulting is N-S striking dextral strike-slip faulting (Group A), with conjugate sets of synthetic R- and antithetic R’-faults. These faults indicate NE-SW compression. The sinistral sense of the N-S trending strike-slip faults in Group C may again indicate tectonic inversion from the dextral strike-slip regime to a sinistral regime (NW-SE compression). In addition to the strike-slip faults, extensional faults are also common (Group B and E, NW-SE extension and NE-SW extension, respectively), although in Group E the amount of observed faults is low for any detailed analysis. The faults in Group B indicate normal dip-slip movement on moderately to gently dipping fault 351 APPENDIX III planes. Group D faults indicate reverse movement on moderately dipping faults, but again the number of observations is too low for further analysis.
Figure 22. Kinematic division of the faults from the VLJ-tunnel into subgroups.
OL-BFZ099
Corrected fault-slip data from the fault zone OL-BFZ099 is shown in (Figure 23), the accepted number of observations being 115. The data set can be easily subdivided into four kinematic groups (Figure 23), group A corresponding to thrusting with a dip-slip component towards SE and an additional strike-slip component, the slip directions striking NE-SW (corresponding to the slip directions of the strike-slip faults of 352 APPENDIX III
ONKALO- and VLJ-tunnel); the formation of these faults can be explained by NW-SE compression. A second group of thrust faults can also be observed (group C), with a slightly varying direction of compression (E-W) compared to group A faults. Group B faults indicate NW-SE extension and normal sip-slip movement on moderately to gently dipping faults and probable reactivation of the original thrust faults represented by group A faults. A set of dextral strike-slip faults can also be identified (group D), although their number is quite low and their orientations do not correspond to the orientation of OL-BFZ099, which probably indicates that the fault measured from the zone may also contain “outliers”, i.e. faults belonging to different zones.
The orientations and dips of the fault planes measured from OL-BFZ099 correspond to the orientation and dip of the OL-BFZ099, with mainly a low-angle dip towards SE. Based on the observations of low-angle faults from the tunnel and the obtained kinematics, it is possible to interpret that the low-angle faults in general originated as thrust faults, the first increment of slip directed approximately towards SE. As a consequence, the kinematics of OL-BFZ099 indicates that the after the thrusting from SE (Group A), the zone was reactivated in a strike-slip (Group A, NW-SE compression) and extensional (Group B, NW-SE extension) regimes. 353 APPENDIX III
Figure 23. Kinematic division of the faults from OL-BFZ099 into subgroups.
OL-BFZ002
Corrected fault-slip data from the fault zone OL-BFZ002 is shown in Figure 24, the accepted number of observations being 46. Both thrust faults (Group A) and extension faults (Group B) can be recognised, and the few NE-SW-trending horizontal slip directions in Group A may indicate reactivation in a strike-slip regime, similarly to OL- BFZ099. The thrusting and the possible strike-slip reactivation can be explained by NNW-SSE compression and normal faulting, which is considered as the reactivation of the zone, by NNW-SSE extension.
Similarly to OL-BFZ099, the orientations and dips of the fault planes measured from OL-BFZ002 correspond to the orientation and dip of the zone, with mainly a low-angle 354 APPENDIX III dip towards SSE. Again the zone can be interpreted to be originated as a thrust fault, the first increment of slip directed approximately towards SSE. The kinematics of OL- BFZ099 indicates that the after the thrusting from SSE (Group A), the zone was reactivated in a strike-slip (Group A, NNW-SSE compression) and extensional (Group B, NNW-SSE extension) regimes.
Figure 24. Kinematic division of the faults from OL-BFZ002 into subgroups.
OL-BFZ098
Corrected fault-slip data from the fault zone OL-BFZ098 is shown in Figure 25 the accepted number of observations being 76. Thrust faulting is the most prominent type of 355 APPENDIX III faulting (Group A), with a dip-slip mainly towards SE. The thrusting can be explained by NWW-SEE compression. Strike-slip faulting (Group B) is also common, with simultaneous reactivation of the low- to moderately dipping faults (presented by NE- SW trending horizontal slip directions on the low-angle faults). The strike-slip faulting is compatible with NW-SE compression. Group C represents faults associated with NNW-SSE extension, with majority of the slip directions plunging towards SE, although compatible slip directions towards SSW and NNE also exist.
The orientations and dips of the fault planes measured from OL-BFZ098 correspond to the orientation and dip of the zone, with mainly a low-angle dip towards SE. The zone can be interpreted to be originated as a thrust fault, the first increment of slip directed approximately towards NW. The kinematics of OL-BFZ098 indicates that the after the thrusting from SE (Group A), the zone was reactivated in a strike-slip (Group B, NW- SE compression) and extensional (Group C, NNW-SSE extension) regimes.
Figure 25. Kinematic division of the faults from OL-BFZ098 into subgroups. 356 APPENDIX III
OL-BFZ053
Corrected fault-slip data from the fault zone OL-BFZ053 is shown in Figure 26 the accepted number of observations being 69. Three distinct kinematical fault groups can be distinguished: NE-SW striking dextral strike-slip faults (Group A), with horizontal slip directions trending NE-SW; the faults in this group originated in E-W compression. Group B represents NE-SW striking sinistral strike-slip faults, with slip directions trending NE-SW. The slip directions and sense-of-movements on Group B faults can be explained by NNW-SSE compression. It is notable that this group also contains few reverse faults dipping moderately towards SE and with slip directions toward SE. Group C faults are moderately- to gently dipping normal faults, with dips towards SE and slip directions mainly towards SEE. The faulting in group C is compatible with NW-SE extension.
The overall orientation of the fault planes measured from OL-BFZ053 corresponds to the orientation of the zone, thus confirming the strike-slip nature of the zone. Yet, it is difficult to interpret which of the dextral and sinistral faulting is the original type of faulting, although Group A faults may indicate that the dextral sense-of movement is the neoformed one as a probable set of conjugate dextral faults trending NEE-SWW exists, corresponding to synthetic Riedel faults. Conjugate sets of faults are not observed for Group B faults. Group C faults indicate that reactivation of the existing strike-slip faults occurred during NW-SE extension. 357 APPENDIX III
Figure 26. Kinematic division of the faults from OL-BFZ053 into subgroups.
OL-BFZ055
Corrected fault-slip data from the fault zone OL-BFZ055 is shown in Figure 27 the accepted number of observations being 26. Two kinematic fault groups can be distinguished: NE-SW striking sinistral strike-slip faults (Group A), with horizontal slip directions trending NE-SW, formed approximately in N-S compression. Group B represents a more heterogeneous group of strike-slip faults, with main strike direction towards NNW-SSE and minor strike directions towards NE-SW and NEE-SWW. The sense-of-slip of the NNW-SSE striking fault set is sinistral as for the NE-SW and NEE- SWW-striking set dextral. 358 APPENDIX III
The overall orientation of the fault planes measured from OL-BFZ055 corresponds to the orientation of the zone, thus confirming the strike-slip nature of the zone. Yet, the number of fault-slip measurements from OL-BFZ055 is quite low, making it difficult to interpret the original sense-of movement of the zone, especially in the lack of clear conjugate sets of faults. Still, it is possible to deduce that reactivation and reversal of the sense-of-movement has occurred on some occasion for OL-BFZ055.
Figure 27. Kinematic division of the faults from OL-BFZ055 into subgroups. 359 APPENDIX III
PRELIMINARY SYNTHESIS
According to the present observations from the ONKALO and VLJ tunnel, outcrops and drillholes and the analysed kinematics, three main brittle deformational regimes can be distinguished from Olkiluoto Island3:
1. NNW-SSE to NWW-SEE contraction (thrusting, neoformed)
The NE-SW striking, low-angle fault zones identified from the ONKALO tunnel and the drillholes of Olkiluoto Island show prominent reverse dip-slip movement, slip directions trending mainly towards SEE-SSE (varying slightly from one zone to another, see Figure 23 to Figure 25), indicating thrusting in approximately NNW-SSE to NWW-SEE oriented contraction. Fault zones OL-BFZ099 and OL-BFZ002 both show similar paleostress orientations (Group A in Figure 23 and Group A in Figure 24, respectively), but this is also anticipated due to the close spatial association of the zones (the zones diverge from each other, representing two splays of one single zone). Fault zone OL-BFZ098 instead shows slightly varying paleostress orientations (Group A in Figure 25, NWW-SEE contraction), which may be explained possibly by the heterogeneity of the stress field during the formation of zone. Similarly oriented thrust faults, formed in E-W-compression, although of smaller numbers, are also observed from the ONKALO fault-slip data (Group C in Figure 21).
2. NNW-SSE to NWW-SEE / NE-SW to E-W contraction (strike-slip)
All the analysed thrust faults show also reactivation in a strike-slip regime, i.e. in addition to the prominent reverse dip-slip movement, the fault planes also contain superimposed horizontal NE-SW-trending slip directions, compatible with slip- directions of the strike-slip faults in the ONKALO (Group A in Figure 21), VLJ-tunnel (Group C in Figure 22), OL-BFZ053 (Group B in Figure 26) and OL-BFZ055 (Group A in Figure 27). In the ONKALO, sinistral strike-slip faults are the main type of faulting, showing well-developed Riedel-geometry, whereas in the VLJ-tunnel (Group A) and the OL-BFZ053 (Group A), dextral strike-slip faulting is more prominent and associated with conjugate Riedel-faults. Yet it is suggested that these two sets of strike-slip faults, with opposing sense of movement, are contemporaneous, caused by heterogeneous movement on opposite blocks of bedrock and local stress perturbations, resulting in both dextral and sinistral strike-slip faults. At later periods, many of the strike-slip faults were reactivated, producing reversals on the sense of movement on the faults.
3. NNW-SSE to NW-SE extension (normal faulting, reactivation)
Both the low-angle faults and strike-slip faults from ONKALO, VLJ-tunnel and drillholes show overprinting normal dip-slip slip directions, indicating later period(s) of NNW-SSE to NE-SE extension (Group D in Figure 21, Group B in Figure 22, Group B
3 The identification is based on observational features and does not exclude the possibility that other regimes may have occurred during the geological history of Olkiluoto 360 APPENDIX III in Figure 23, Group B in Figure 24, Group C in Figure 25 and Group C in Figure 26). The slip direction is trending mainly towards SSE-SE and is more prominent on the thrust faults than on the strike-slip faults.
The final stages of the ductile deformation at Olkiluoto are characterised by thrust- related structures, mainly overturned or recumbent folds and shearing associated with the D3 and D4-stages. Based on the observations from the ONKALO tunnel, low-angle ductile shearing associated with recumbent folds acted as a precursor for the subsequent faulting, recording long-continuing thrusting in the area. Many of the current fault zones overprint ductile shear zones associated with a “rim” of K-feldspar porphyry, which is interpreted to be formed during shearing in the D4 stage. The U-Pb analysis of the K- feldspar porphyry associated with the D4 shearing yielded youngest metamorphic ages of 1850-1830 Ma (Mänttäri et al. 2007), which is considered as the minimum age of the D4 shearing and the maximum age of the brittle thrusting. Therefore, it can be argumented that the ductile and brittle structures indicate that the Olkiluoto Island is a fold-thrust system, with the beginning of its roots at the final stages of the Fennian Orogeny, approximately at 1860-1830 Ma ago. The deformation at the brittle stage started as the reactivation (as a direct continuation of or overlapping with ductile deformation) of low-angle D4 shears and thrusting towards NW/NNW during NNW- SSE to NWW-SEE contraction. The extensional Subjotnian period at 1650-1550 Ma, related to the emplacement of the rapakivi granites, the intrusion of the Subjotnian diabase dikes and the formation of the Satakunta graben, is considered as the minimum age for the end of the thrusting. At Olkiluoto this period is recorded by the intrusion of diabase dikes of the age 1560 Ma (Mertanen et al. 2007, Mänttäri et al. 2006) into NEE- SWW trending fractures and this period is also marked by the formation of greisen veins (Suominen et al. 1997).
The age of the strike-slip faulting at Olkiluoto can be constrained by the crosscutting relationship between the younger faults and older Subjotnian diabase dikes, indicating that the maximum age of the strike-slip faults is ca. 1560 Ma. In addition, K-Ar age determination of authigenic mineral fractions of two samples from the fault breccias of the storage hall fault yielded two consistent ages of 1385±27 Ma and 1373±27 Ma (Mänttäri et al. 2007), indicating that the minimum age for the strike-slip faulting is approximately 1370 Ma. Yet, if the possible K-contamination due to detrimental K- feldspar is taken into account, the minimum age can be lowered to 1270 Ma, i.e. corresponding to Mesoproterozoic Postjotnian events (Mänttäri et al. 2007). During this time interval, the existing thrust faults were also reactivated and superimposed by horizontal slip directions, corresponding to the slip direction of the strike-slip faults. It is noteworthy to mention that the period at 1650-1100 Ma are usually associated with extension (formation of rapakivi granites and diabases), yet, by the current evidence from Olkiluoto it seems that wrench tectonics may have had more important role at this period than previously assumed, yet this has not been recorder on scientific publications. Therefore, further studies are needed to constrain the age, mechanics and importance of the strike-slip faults in the Olkiluoto and Satakunta area.
Both the thrust and strike-slip faults also record overprinting normal slip directions, indicating that on some occasions these were reactivated on extensional regime. For thrust faults, this may have occurred in the Subjotnian period or at later events, whereas the strike-slip faults, which are presumably close to Postjotnian in age, must have been reactivated at clearly younger ages. Possible ages for the reactivations are given by the K-Ar ages of fault breccia samples from the ONKALO tunnel (Mänttäri et al. 2007): A 361 APPENDIX III low-angle thrust fault located in the tunnel section of 960 metres, gave an age of 1225±24 Ma for the authigenic mineral fraction, corresponding to Mesoproterozoic age (Postjotnian event). A subvertical strike-slip fault, located in the tunnel chainage of 65 metres, gave an age of 912±18 Ma, corresponding to Neoproterozoic age, and a thrust fault located at the chainage 87 metres, an age of 550±11 Ma, corresponding to Neoproterozoic-Lower Cambrian age. Consequently, the ages of the fault breccia samples indicate that the reactivation of faults may have occurred repeatedly, plausibly during the Postjotnian period (onset of the Sweconorwegian orogeny) at 1300-1100 Ma ago, during the Neoproterozoic exhumation stage at ca. 900-600 Ma and during the stage of platform sedimentation at ca. 600-420 and possibly during the Caledonian foreland stage at ca. 420-350 Ma. Yet the main argumentation from the fault analysis is that the at Olkiluoto, the main fault zones were formed already before or at the Mesoproterozoic stage, and consequently, during subsequent periods reactivation played more important role than the formation of new structures. The inferred sequences of deformation are shown schematically in Figure 28. 362 APPENDIX III
Figure 28. A schematic representation of the brittle deformation at Olkiluoto from 1850 Ma onwards. (A) Crustal shortening and thrusting at approximately 1850-1830 Ma to 1560 Ma; (B) Extension at 1560 Ma and the intrusion of diabase dykes; (C) Formation of strike-slip faults and reactivation of older structures at approximately 1560-1270 Ma; (D) Extension during or after 1270 Ma and reactivation of existing structures. Thick black arrows indicate the direction of maximum crustal contraction or extension and thin arrows the sense of movement. See text for further explanation. View from above, the top of the Figure is towards north.
. 363 APPENDIX III
FUTURE ACTIVITIES
The fault analysis presented here will be continued in the near future and more focus will be put on the evaluation of tunnel data and quantitative laboratory analysis to constrain the age and evolution of the faults in more detail. In addition, a microscopic characterisation of the faults will be performed, combined with mineralogical analysis. As the data on fault displacements is still scarce, estimates on the displacements will be given through the correlation of fault thickness and displacement ratios, in order to fulfil the kinematic analysis. 364 APPENDIX III 365 APPENDIX III
REFERENCES
Angelier, J. & Mechler, P., 1977. Sur une méthode graphique de recherché des contraintes principles également utilisable en tectonique et en séismologie : la méthode des dièdres droits. Bull. Soc. Géol. Fr. 7, 1309-1318.
Angelier, J., 1994. Fault slip analysis and paleostress reconstruction. In: Continental deformation (Edited by Hancock P. L.). Pergamon press, 53-100.
Mattila, J., Aaltonen, I., Kemppainen, K., Talikka, M., 2007. Geological mapping of the investigation trench OL-TK11, the strorage hall area. Posiva Oy, Working Report WR 2007-27.
Marret, R., & Allmendinger, R. W., 1990. Kinematic analysis of fault slip data. Journal of Structural Geology, Vol. 12, No. 8. pp 973-986.
Mertanen, S., 2007. Paleomagnetism of diabase dykes, pegmatite granites ad TGG gneisses in the Olkiluoto area. Posiva Oy, Working Report WR 2007-XX, Eurajoki.
Mänttäri, I., Mattila, J., Zwingmann, H., Todd, A. J., 2007. Illite K-Ar dating of fault breccia samples from ONKALO underground research facility, Olkiluoto, Eurajoki, SW Finland. Posiva Oy, Working Report WR 2007-67.
Mänttäri, I., Aaltonen, I., Lindberg, A., 2007. U-Pb-ages for two tonalitic gneisses, pegmatitic granites and K-feldspar porphyries, Olkiluoto Study Site, Eurajoki, SW Finland. Posiva Oy, Working Report WR 2007-70.
Ortner, H., Reiter, F., Acs, P., 2002. Easy handling of tectonic data: the programs TectonicVB for Mac and TectonicsFP for Windows. Computers & Geosciences, 28, pp. 1193-1200.
Ramsay, J. G. & Lisle, R. J., 2000. The techniques of modern structural geology, Volume 3: applications of continuum mechanics in structural geology. Elsevier, London.
Suominen, V., Fagerström, P., Torssonen, M., 1997. Pre-Quaternary rocks of the Rauma map sheet area (In Finnish with english summary). Geological Survey of Finland. Espoo 1997. 54 p. 366 367 APPENDIX IV 368 369 APPENDIX V Simplified lithology from drillholes
DRILLHOLE FROM TO LEUCOSOME LITHOLOGY (%) OL-KR1 40.20 56.80 55 DGN OL-KR1 56.80 169.05 40 VGN OL-KR1 169.05 199.40 98 PGR OL-KR1 199.40 221.30 35 DGN OL-KR1 221.30 276.40 50 VGN OL-KR1 276.40 287.40 5 QGN OL-KR1 287.40 326.50 20 VGN OL-KR1 326.50 336.60 5 TGG OL-KR1 336.60 348.10 95 PGR OL-KR1 348.10 377.60 15 VGN OL-KR1 377.60 385.70 90 PGR OL-KR1 385.70 393.70 5 STG OL-KR1 393.70 395.05 90 PGR OL-KR1 395.05 419.70 20 VGN OL-KR1 419.70 427.85 90 PGR OL-KR1 427.85 441.90 5 TGG OL-KR1 441.90 454.80 95 PGR OL-KR1 454.80 469.90 10 VGN OL-KR1 469.90 488.95 90 PGR OL-KR1 488.95 601.00 25 VGN OL-KR1 601.00 629.05 45 DGN OL-KR1 629.05 638.30 5 TGG OL-KR1 638.30 756.70 45 VGN OL-KR1 756.70 765.60 0 TGG OL-KR1 765.60 790.00 35 VGN OL-KR1 790.00 808.40 0 TGG OL-KR1 808.40 920.15 30 VGN OL-KR1 920.15 935.30 98 PGR OL-KR1 935.30 946.00 0 TGG OL-KR1 946.00 976.00 95 PGR OL-KR1 976.00 998.00 30 DGN OL-KR1 998.00 1001.05 20 VGN
OL-KR2 40.35 72.80 40 VGN OL-KR2 72.80 81.05 90 PGR OL-KR2 81.05 139.85 50 VGN OL-KR2 139.85 174.80 95 PGR OL-KR2 174.80 196.80 10 TGG OL-KR2 196.80 214.75 50 VGN OL-KR2 214.75 227.40 90 PGR OL-KR2 227.40 238.30 40 VGN OL-KR2 238.30 245.90 95 PGR OL-KR2 245.90 297.10 50 VGN OL-KR2 297.10 398.50 10 TGG OL-KR2 398.50 421.30 25 VGN OL-KR2 421.30 455.90 95 PGR OL-KR2 455.90 742.85 40 VGN 370 APPENDIX V Simplified lithology from drillholes, continued
OL-KR2 742.85 758.75 95 PGR OL-KR2 758.75 768.50 10 TGG OL-KR2 768.50 815.10 95 PGR OL-KR2 815.10 821.10 10 VGN OL-KR2 821.10 843.15 90 PGR OL-KR2 843.15 889.95 35 VGN OL-KR2 889.95 909.95 15 TGG OL-KR2 909.95 936.45 97 PGR OL-KR2 936.45 955.25 5 TGG OL-KR2 955.25 962.25 10 MGN OL-KR2 962.25 968.40 90 PGR OL-KR2 968.40 1006.45 20 STG OL-KR2 1006.45 1012.90 90 PGR OL-KR2 1012.90 1039.35 15 MGN OL-KR2 1039.35 1051.50 15 VGN OL-KR2 1051.50 1051.89 90 PGR
OL-KR3 40.58 76.65 5 MGN OL-KR3 76.65 80.05 98 PGR OL-KR3 80.05 86.45 70 DGN OL-KR3 86.45 138.30 0 MGN OL-KR3 138.30 156.85 40 DGN OL-KR3 156.85 180.40 80 PGR OL-KR3 180.40 189.05 60 DGN OL-KR3 189.05 197.65 95 PGR OL-KR3 197.65 264.60 50 DGN OL-KR3 264.60 294.20 25 VGN OL-KR3 294.20 305.45 98 PGR OL-KR3 305.45 452.85 15 VGN OL-KR3 452.85 462.65 97 PGR OL-KR3 462.65 502.00 50 VGN
OL-KR4 40.00 332.95 70 DGN OL-KR4 332.95 381.40 50 VGN OL-KR4 381.30 410.20 60 DGN OL-KR4 410.20 422.75 35 VGN OL-KR4 422.75 433.00 80 PGR OL-KR4 433.00 455.00 60 DGN OL-KR4 455.00 464.50 40 VGN OL-KR4 464.50 483.20 90 PGR OL-KR4 483.20 589.65 30 VGN OL-KR4 589.65 606.65 90 PGR OL-KR4 606.65 769.65 35 VGN OL-KR4 769.65 807.00 80 PGR OL-KR4 807.00 815.80 50 VGN OL-KR4 815.80 866.30 95 PGR OL-KR4 866.30 901.58 20 VGN
OL-KR5 40.15 151.00 50 VGN 371 APPENDIX V Simplified lithology from drillholes, continued
OL-KR5 151.00 256.70 10 TGG OL-KR5 256.70 314.60 5 VGN OL-KR5 314.60 335.20 5 MFGN OL-KR5 335.20 342.05 80 PGR OL-KR5 342.05 361.00 3 TGG OL-KR5 361.00 385.90 4 MGN OL-KR5 385.90 559.00 40 VGN
OL-KR6 4.80 31.95 40 VGN OL-KR6 31.95 42.50 5 TGG OL-KR6 42.50 67.55 30 VGN OL-KR6 67.55 76.60 75 PGR OL-KR6 76.60 82.15 40 VGN OL-KR6 82.15 103.25 75 PGR OL-KR6 103.25 164.20 20 VGN OL-KR6 164.20 263.00 50 VGN OL-KR6 263.00 275.30 90 PGR OL-KR6 275.30 304.50 50 DGN OL-KR6 304.50 334.40 40 VGN OL-KR6 334.40 347.50 70 PGR OL-KR6 347.50 393.75 40 VGN OL-KR6 393.75 395.90 0 MDB OL-KR6 395.90 398.40 40 DGN OL-KR6 398.40 399.45 0 MDB OL-KR6 399.45 591.60 20 VGN OL-KR6 591.60 600.77 60 PGR
OL-KR7 0.60 14.80 40 DGN OL-KR7 14.80 88.20 30 VGN OL-KR7 88.20 105.50 65 DGN OL-KR7 105.50 117.90 95 PGR OL-KR7 117.90 136.00 5 MGN OL-KR7 136.00 173.00 30 VGN OL-KR7 173.00 185.40 65 DGN OL-KR7 185.40 202.15 50 VGN OL-KR7 202.15 213.80 10 MFGN OL-KR7 213.80 225.40 80 PGR OL-KR7 225.40 228.40 40 VGN OL-KR7 228.40 253.30 10 MGN OL-KR7 253.30 258.60 50 VGN OL-KR7 258.60 285.95 80 PGR OL-KR7 285.95 300.40 15 VGN OL-KR7 300.40 322.25 10 MGN OL-KR7 322.25 653.00 30 VGN OL-KR7 653.00 694.60 95 PGR OL-KR7 694.60 706.42 15 VGN OL-KR7 706.42 723.30 98 PGR OL-KR7 723.30 811.05 15 VGN
372 APPENDIX V Simplified lithology from drillholes, continued
OL-KR8 2.07 14.85 60 DGN OL-KR8 14.85 30.80 50 TGG OL-KR8 30.80 55.55 40 VGN OL-KR8 55.55 67.40 80 PGR OL-KR8 67.40 77.95 50 TGG OL-KR8 77.95 194.85 60 DGN OL-KR8 194.85 210.20 95 PGR OL-KR8 210.20 266.15 5 TGG OL-KR8 266.15 524.40 60 DGN OL-KR8 524.40 535.45 90 PGR OL-KR8 535.45 565.40 50 DGN OL-KR8 565.40 600.59 95 PGR
OL-KR9 40.14 50.00 DGN OL-KR9 50.00 68.80 TGG OL-KR9 68.80 114.10 DGN OL-KR9 114.10 136.10 VGN OL-KR9 136.10 183.20 DGN OL-KR9 183.20 199.40 PGR OL-KR9 199.40 238.00 DGN OL-KR9 238.00 275.60 VGN OL-KR9 275.60 304.10 DGN OL-KR9 304.10 328.40 PGR OL-KR9 328.40 352.80 DGN OL-KR9 352.80 370.10 PGR OL-KR9 370.10 461.15 DGN OL-KR9 461.15 475.30 MGN OL-KR9 475.30 551.80 VGN OL-KR9 551.80 560.85 PGR OL-KR9 560.85 601.25 DGN
OL-KR10 40.50 75.00 DGN OL-KR10 75.00 128.70 VGN OL-KR10 128.70 136.10 PGR OL-KR10 136.10 146.30 VGN OL-KR10 149.80 161.85 MGN OL-KR10 161.85 202.60 DGN OL-KR10 202.60 246.60 PGR OL-KR10 246.60 277.10 VGN OL-KR10 277.10 336.85 DGN OL-KR10 336.85 349.05 PGR OL-KR10 349.05 364.95 DGN OL-KR10 364.95 466.30 VGN OL-KR10 466.30 482.50 MGN OL-KR10 482.50 614.30 VGN
OL-KR11 40.30 152.50 VGN OL-KR11 152.50 180.20 DGN OL-KR11 180.20 192.05 PGR 373 APPENDIX V Simplified lithology from drillholes, continued
OL-KR11 192.05 199.00 DGN OL-KR11 199.00 208.00 PGR OL-KR11 208.00 305.37 VGN OL-KR11 305.37 330.35 PGR OL-KR11 330.35 441.20 VGN OL-KR11 441.20 461.05 TGG OL-KR11 461.05 825.10 VGN OL-KR11 825.10 848.72 PGR OL-KR11 848.72 853.90 MGN OL-KR11 853.90 881.75 PGR OL-KR11 881.75 899.10 DGN OL-KR11 899.10 921.00 PGR OL-KR11 921.00 949.30 MGN OL-KR11 949.30 977.50 PGR OL-KR11 977.50 1002.11 TGG
OL-KR12 40.20 57.00 PGR OL-KR12 57.00 87.90 DGN OL-KR12 87.90 133.20 VGN OL-KR12 133.20 143.20 PGR OL-KR12 143.20 186.00 VGN OL-KR12 186.00 197.00 PGR OL-KR12 197.00 208.10 DGN OL-KR12 208.10 225.30 PGR OL-KR12 225.30 268.30 DGN OL-KR12 268.30 281.35 TGG OL-KR12 281.35 294.50 VGN OL-KR12 294.50 371.55 DGN OL-KR12 371.55 383.15 TGG OL-KR12 383.15 406.65 DGN OL-KR12 406.65 495.40 TGG OL-KR12 495.40 509.70 VGN OL-KR12 509.70 522.60 PGR OL-KR12 522.60 536.90 VGN OL-KR12 536.90 545.10 PGR OL-KR12 545.10 551.10 VGN OL-KR12 551.10 567.10 PGR OL-KR12 567.10 589.15 VGN OL-KR12 589.15 600.30 DGN OL-KR12 600.30 616.40 PGR OL-KR12 616.40 626.80 MGN OL-KR12 626.80 634.30 DGN OL-KR12 634.30 644.50 PGR OL-KR12 644.50 654.40 VGN OL-KR12 654.40 679.75 DGN OL-KR12 679.75 795.34 VGN
OL-KR13 2.30 68.05 50 DGN OL-KR13 68.05 106.10 95 PGR 374 APPENDIX V Simplified lithology from drillholes, continued
OL-KR13 106.10 115.70 40 DGN OL-KR13 115.70 150.60 95 PGR OL-KR13 150.60 188.00 50 DGN OL-KR13 188.00 268.70 15 VGN OL-KR13 268.70 271.28 98 PGR OL-KR13 271.28 410.00 10 TGG OL-KR13 410.50 489.85 35 VGN OL-KR13 489.85 500.21 95 PGR
OL-KR14 6.20 95.35 65 VGN OL-KR14 95.35 153.65 95 PGR OL-KR14 153.65 282.70 25 VGN OL-KR14 282.70 293.90 90 PGR OL-KR14 293.90 300.75 20 VGN OL-KR14 300.75 311.10 95 PGR OL-KR14 311.10 354.50 35 VGN OL-KR14 354.50 368.30 95 PGR OL-KR14 368.30 389.95 10 TGG OL-KR14 389.95 411.35 20 VGN OL-KR14 411.35 448.00 10 TGG OL-KR14 448.00 462.20 25 VGN OL-KR14 485.70 508.85 98 PGR OL-KR14 508.85 514.10 15 VGN
OL-KR15 39.90 61.54 40 DGN OL-KR15 61.54 88.78 95 PGR OL-KR15 88.78 96.40 50 DGN OL-KR15 96.40 108.90 15 TGG OL-KR15 108.90 293.25 45 VGN OL-KR15 293.25 306.60 90 PGR OL-KR15 306.60 359.65 30 VGN OL-KR15 359.65 395.35 20 TGG OL-KR15 395.35 423.75 95 PGR OL-KR15 423.75 463.30 10 MGN OL-KR15 463.30 478.90 40 DGN OL-KR15 478.90 505.00 97 PGR OL-KR15 505.00 518.85 14 VGN
OL-KR16 40.37 86.65 60 DGN OL-KR16 86.65 117.75 98 PGR OL-KR16 117.75 141.90 55 DGN OL-KR16 141.90 170.20 40 VGN
OL-KR17 40.00 48.80 98 PGR OL-KR17 48.80 56.55 40 VGN OL-KR17 56.55 80.22 95 PGR OL-KR17 80.22 88.00 45 DGN OL-KR17 88.00 105.20 5 MGN OL-KR17 105.20 157.13 30 VGN 375 APPENDIX V Simplified lithology from drillholes, continued
OL-KR18 39.84 58.40 50 VGN OL-KR18 58.40 79.00 95 PGR OL-KR18 79.00 85.00 70 TGG OL-KR18 85.00 91.90 30 DGN OL-KR18 91.90 100.40 40 VGN OL-KR18 100.40 123.85 90 PGR OL-KR18 123.85 125.49 30 VGN
OL-KR19 40.60 79.95 10 VGN OL-KR19 79.95 87.40 100 PGR OL-KR19 87.40 132.25 20 VGN OL-KR19 132.25 139.00 3 TGG OL-KR19 139.00 146.00 30 VGN OL-KR19 157.40 162.45 15 TGG OL-KR19 162.45 175.30 20 VGN OL-KR19 175.30 182.50 5 TGG OL-KR19 182.50 224.80 15 VGN OL-KR19 224.80 233.04 95 PGR OL-KR19 233.04 259.00 5 MGN OL-KR19 259.00 287.65 25 VGN OL-KR19 287.65 295.61 80 PGR OL-KR19 295.61 364.05 25 VGN OL-KR19 364.05 372.05 5 MFGN OL-KR19 372.05 464.15 20 VGN OL-KR19 464.15 470.70 20 QGN OL-KR19 470.70 478.55 95 PGR OL-KR19 478.55 484.35 5 MGN OL-KR19 484.35 490.10 50 VGN OL-KR19 490.10 500.40 10 MGN OL-KR19 500.40 544.34 25 VGN
OL-KR20 40.78 43.93 25 DGN OL-KR20 43.93 51.35 10 QGN OL-KR20 51.35 63.60 35 VGN OL-KR20 63.60 87.60 100 PGR OL-KR20 87.60 96.35 30 VGN OL-KR20 96.35 104.10 98 PGR OL-KR20 104.10 144.15 25 VGN OL-KR20 144.15 162.95 95 PGR OL-KR20 162.95 181.70 50 DGN OL-KR20 181.70 199.05 95 PGR OL-KR20 199.05 251.40 20 VGN OL-KR20 251.40 359.20 5 TGG OL-KR20 359.20 480.00 30 VGN OL-KR20 480.00 494.72 8 MGN
OL-KR21 2.95 19.30 90 PGR OL-KR21 19.30 57.20 30 VGN 376 APPENDIX V Simplified lithology from drillholes, continued
OL-KR21 57.20 82.40 95 PGR OL-KR21 82.40 111.20 5 TGG OL-KR21 111.20 120.45 10 MGN OL-KR21 120.45 160.70 40 VGN OL-KR21 162.55 183.10 30 VGN OL-KR21 183.10 197.00 95 PGR OL-KR21 197.00 301.08 30 VGN
OL-KR22 40.66 109.25 70 DGN OL-KR22 109.25 138.20 30 VGN OL-KR22 138.20 374.95 50 DGN OL-KR22 374.95 424.50 35 VGN OL-KR22 424.50 483.96 10 MGN OL-KR22 483.96 500.00 35 VGN
OL-KR22B 8.15 20.75 75 PGR OL-KR22B 20.75 45.55 75 DGN
OL-KR23 40.40 185.10 70 DGN OL-KR23 185.10 203.75 70 PGR OL-KR23 203.75 302.10 50 DGN
OL-KR23B 3.75 45.12 65 DGN
OL-KR24 0.00 27.10 65 DGN OL-KR24 27.10 40.15 35 VGN OL-KR24 45.20 99.05 50 DGN OL-KR24 99.05 116.50 30 VGN OL-KR24 116.50 124.10 5 MFGN OL-KR24 124.10 150.48 30 VGN OL-KR24 150.48 308.80 60 DGN OL-KR24 308.80 326.00 40 VGN OL-KR24 326.00 368.75 70 DGN OL-KR24 368.75 399.05 30 MGN OL-KR24 399.05 413.60 85 PGR OL-KR24 413.60 539.30 40 VGN OL-KR24 539.30 548.05 98 PGR OL-KR24 548.05 551.11 30 VGN
OL-KR25 40.22 56.60 40 VGN OL-KR25 56.60 130.85 60 DGN OL-KR25 130.85 140.90 80 PGR OL-KR25 140.90 247.25 55 DGN OL-KR25 247.25 258.00 80 PGR OL-KR25 258.00 301.00 70 VGN OL-KR25 301.00 319.60 50 DGN OL-KR25 319.60 332.80 70 PGR OL-KR25 332.80 357.80 60 DGN OL-KR25 357.80 392.85 25 VGN 377 APPENDIX V Simplified lithology from drillholes, continued
OL-KR25 392.85 400.20 70 DGN OL-KR25 400.20 437.95 15 VGN OL-KR25 437.95 462.45 95 PGR OL-KR25 462.45 604.87 35 VGN
OL-KR26 0.40 103.00 60 DGN
OL-KR27 40.06 111.60 70 DGN OL-KR27 111.60 136.70 0 KFP OL-KR27 136.70 156.20 5 TGG OL-KR27 156.20 276.55 65 DGN OL-KR27 276.55 288.20 20 MGN OL-KR27 288.20 304.30 60 DGN OL-KR27 304.30 318.80 85 KFP OL-KR27 318.80 362.00 60 DGN OL-KR27 362.00 401.60 98 PGR OL-KR27 401.60 426.70 40 DGN OL-KR27 426.70 440.30 95 KFP OL-KR27 440.30 465.40 30 DGN OL-KR27 465.40 473.15 5 MFGN OL-KR27 473.15 485.00 70 PGR OL-KR27 485.00 493.30 5 MGN OL-KR27 493.30 550.84 20 VGN
OL-KR28 40.06 98.30 70 DGN OL-KR28 98.30 162.70 45 VGN OL-KR28 162.70 369.20 70 DGN OL-KR28 369.20 507.50 40 VGN OL-KR28 507.50 520.80 55 DGN OL-KR28 520.80 559.87 100 PGR OL-KR28 559.87 642.30 35 VGN OL-KR28 642.30 656.33 5 MFGN
OL-KR29 40.02 222.45 60 DGN OL-KR29 222.45 240.75 40 VGN OL-KR29 240.75 282.80 50 DGN OL-KR29 282.80 325.60 5 MFGN OL-KR29 325.60 345.80 10 MGN OL-KR29 345.80 355.70 5 MFGN OL-KR29 355.70 372.80 5 MGN OL-KR29 372.80 384.40 10 MFGN OL-KR29 384.40 454.05 30 VGN OL-KR29 454.05 514.70 25 MGN OL-KR29 514.70 523.40 98 PGR OL-KR29 523.40 543.60 35 VGN OL-KR29 543.60 582.40 60 DGN OL-KR29 582.40 649.00 40 VGN OL-KR29 649.00 652.95 65 DGN OL-KR29 652.95 870.18 35 VGN 378 APPENDIX V Simplified lithology from drillholes, continued
OL-KR29B 0.87 45.60 60 DGN
OL-KR30 0.96 4.20 70 DGN OL-KR30 4.20 27.65 2 TGG OL-KR30 27.65 37.90 90 PGR OL-KR30 37.90 60.15 65 DGN OL-KR30 60.15 70.30 30 VGN OL-KR30 70.30 98.28 60 DGN
OL-KR31 40.10 204.45 70 DGN OL-KR31 204.45 219.15 80 PGR OL-KR31 219.15 340.15 50 DGN
OL-KR31B 5.40 45.18 60 DGN
OL-KR32 0.00 119.70 50 DGN OL-KR32 119.70 139.90 90 PGR OL-KR32 139.90 142.15 80 DGN OL-KR32 142.15 151.80 10 TGG OL-KR32 151.80 191.81 25 VGN
OL-KR33 40.10 46.40 80 PGR OL-KR33 46.40 104.40 45 VGN OL-KR33 104.40 116.95 100 PGR OL-KR33 116.95 125.60 15 TGG OL-KR33 125.60 130.20 100 PGR OL-KR33 130.20 141.00 15 VGN OL-KR33 143.05 266.50 5 TGG OL-KR33 266.50 311.02 40 VGN
OL-KR33B 4.73 13.35 10 MGN OL-KR33B 13.35 45.53 0 PGR
OL-KR34 2.60 100.07 70 DGN
OL-KR35 1.70 100.87 70 DGN
OL-KR36 0.00 205.17 70 DGN
OL-KR37 39.96 75.80 60 DGN OL-KR37 75.80 105.90 35 VGN OL-KR37 105.90 138.60 75 PGR OL-KR37 138.60 179.50 10 TGG OL-KR37 179.50 350.00 65 DGN
OL-KR37B 2.17 45.10 60 DGN
OL-KR38 0.00 59.00 75 DGN 379 APPENDIX V Simplified lithology from drillholes, continued
OL-KR38 59.00 81.10 30 VGN OL-KR38 81.10 145.20 60 DGN OL-KR38 145.20 159.85 45 VGN OL-KR38 159.85 163.75 70 DGN OL-KR38 163.75 203.95 99 PGR OL-KR38 203.95 231.70 70 DGN OL-KR38 231.70 241.40 40 MGN OL-KR38 241.40 346.60 65 DGN OL-KR38 346.60 354.90 98 PGR OL-KR38 354.90 373.95 40 VGN OL-KR38 373.95 383.85 55 DGN OL-KR38 383.85 403.10 98 PGR OL-KR38 403.10 491.00 25 VGN OL-KR38 491.00 527.50 98 PGR OL-KR38 527.50 530.60 60 DGN
OL-KR39 40.07 61.90 20 VGN OL-KR39 61.90 72.05 0 KFP OL-KR39 72.05 79.70 100 PGR OL-KR39 79.70 106.45 5 MGN OL-KR39 106.45 144.40 98 PGR OL-KR39 144.40 172.60 25 VGN OL-KR39 172.60 190.00 70 DGN OL-KR39 190.00 222.40 20 VGN OL-KR39 222.40 237.90 10 MGN OL-KR39 237.90 251.00 98 PGR OL-KR39 251.00 285.10 25 VGN OL-KR39 285.10 297.30 75 PGR OL-KR39 297.30 314.05 40 VGN OL-KR39 314.05 324.40 80 PGR OL-KR39 324.40 473.10 30 VGN OL-KR39 473.10 496.90 97 PGR OL-KR39 496.90 502.97 25 VGN
OL-KR39B 0.20 3.98 97 PGR OL-KR39B 3.98 45.11 70 DGN
OL-KR40 40.16 65.50 50 DGN OL-KR40 65.50 126.70 0 KFP OL-KR40 126.70 153.60 60 DGN OL-KR40 153.60 169.80 15 TGG OL-KR40 169.80 216.40 70 DGN OL-KR40 216.40 238.90 0 KFP OL-KR40 238.90 375.80 65 DGN OL-KR40 375.80 390.20 85 PGR OL-KR40 390.20 406.60 80 DGN OL-KR40 406.60 459.70 98 PGR OL-KR40 459.70 478.15 0 KFP OL-KR40 478.15 529.20 60 DGN 380 APPENDIX V Simplified lithology from drillholes, continued
OL-KR40 529.20 538.00 0 TGG OL-KR40 538.00 540.20 100 PGR OL-KR40 540.20 543.40 0 KFP OL-KR40 543.40 568.40 2 MFGN OL-KR40 568.40 571.60 0 KFP OL-KR40 571.60 587.20 20 VGN OL-KR40 587.20 595.53 99 PGR OL-KR40 595.53 617.40 25 VGN OL-KR40 617.40 630.50 99 PGR OL-KR40 630.50 751.75 25 VGN OL-KR40 751.75 791.60 100 PGR OL-KR40 791.60 928.15 20 VGN OL-KR40 928.15 937.20 100 PGR OL-KR40 937.20 988.35 15 VGN OL-KR40 988.35 1017.20 85 PGR OL-KR40 1017.20 1030.51 20 VGN
OL-KR41 39.65 46.50 VGN OL-KR41 46.50 84.00 PGR OL-KR41 84.00 101.50 VGN OL-KR41 101.50 111.50 DGN OL-KR41 111.50 126.60 VGN OL-KR41 126.60 135.70 DGN OL-KR41 135.70 160.80 VGN OL-KR41 160.80 174.60 PGR OL-KR41 174.60 181.65 VGN OL-KR41 181.65 191.50 PGR OL-KR41 191.50 238.30 VGN OL-KR41 238.30 271.60 TGG OL-KR41 271.60 300.15 VGN OL-KR41 300.15 363.55 DGN OL-KR41 363.55 401.42 VGN
OL-KR41B 4.05 12.40 VGN OL-KR41B 12.40 33.10 DGN OL-KR41B 33.10 45.60 VGN
OL-KR42 40.02 57.35 DGN OL-KR42 57.35 71.70 PGR OL-KR42 71.70 79.50 VGN OL-KR42 79.50 124.20 DGN OL-KR42 124.20 162.80 VGN OL-KR42 162.80 175.60 DGN OL-KR42 175.60 221.55 VGN OL-KR42 221.55 272.70 DGN OL-KR42 272.70 285.50 VGN OL-KR42 285.50 295.90 DGN OL-KR42 295.90 304.30 VGN OL-KR42 304.30 310.25 DGN 381 APPENDIX V Simplified lithology from drillholes, continued
OL-KR42 310.25 329.90 VGN OL-KR42 329.90 337.90 DGN OL-KR42 337.90 360.20 VGN OL-KR42 360.20 375.00 DGN OL-KR42 375.00 385.00 MGN OL-KR42 385.00 392.85 TGG OL-KR42 392.85 398.00 PGR OL-KR42 398.00 400.85 VGN
OL-KR42B 2.60 24.75 DGN OL-KR42B 24.75 32.20 PGR OL-KR42B 32.20 45.00 DGN
OL-KR43 40.35 42.60 VGN OL-KR43 42.60 87.60 TGG OL-KR43 87.60 167.40 VGN OL-KR43 167.40 174.35 MFGN OL-KR43 174.35 215.35 VGN OL-KR43 215.35 234.20 DGN OL-KR43 234.20 245.35 DGN OL-KR43 245.35 317.40 VGN OL-KR43 317.40 347.00 DGN OL-KR43 347.00 492.60 VGN OL-KR43 492.60 544.40 PGR OL-KR43 544.40 603.85 VGN OL-KR43 603.85 615.65 PGR OL-KR43 615.65 653.90 VGN OL-KR43 653.90 669.95 DGN OL-KR43 669.95 694.95 VGN OL-KR43 694.95 731.55 DGN OL-KR43 739.20 746.70 VGN OL-KR43 746.70 751.75 DGN OL-KR43 751.75 768.15 VGN OL-KR43 768.15 797.25 PGR OL-KR43 797.25 805.85 DGN OL-KR43 805.85 833.85 VGN OL-KR43 833.85 842.35 DGN OL-KR43 842.35 899.85 VGN OL-KR43 899.85 914.30 DGN OL-KR43 914.30 927.55 TGG OL-KR43 927.55 940.25 PGR OL-KR43 940.25 1000.26 VGN
OL-KR43B 1.95 45.01 TGG 382 383 APPENDIX VI
Assessment of the applicability of lineament data in the brittle deformation zone modelling
The lineament interpretation data of the Olkiluoto area comprises both geophysical and topographic data (Korhonen et al. 2005). The geophysical data included magnetic and electromagnetic (EM) data from aerogeophysical surveys, magnetic, EM, and seismic data from ground surveys, and acoustic data from a marine survey. The topographic data was composed of two digital elevation models and 5-metre elevation contours. The digital elevation models used were the 25-metre pixel-size National Land Survey (NLS) digital elevation model (DEM) of Finland and a detailed DEM of the Olkiluoto island. The lineament interpretation was performed in three phases according to the methodologies developed by the Swedish Nuclear Fuel and Waste Management Co. (SKB) and described in the method descriptions SKB MD 120.001 (Metodbeskrivning för lineamentstolkning baserad på topografiska data) and SKB MD 211.003 (Metodbeskrivning för tolkning av flyggeofysiska data). In the first phase, each method- specific data set was interpreted separately. In the next phase, those method-specific lineaments that describe the same linear feature were coordinated. Finally, the coordinated lineaments assumed to describe the same linear feature were linked into a single lineament. The method-specific lineament interpretation has a total of 1334 lineaments, which dropped to 998 lineaments in the coordinated lineament interpretation phase. The final lineament interpretation of the Olkiluoto study site has 609 linked lineaments (Figure 1). 384 APPENDIX VI
1520000 1525000 1530000 6795000 6795000 6790000 6790000
1520000 1525000 1530000 Linked lineaments Low uncertainty (< 1.5) 012345 Medium uncertainty (1.5 - 2.5) km High uncertainty (> 2.5)
Figure 1. Linked lineaments classified by their uncertainties (Korhonen et al. 2005).
A lineament is a straight or curved feature, which can be seen, e.g., in topographic maps, aerial photographs or aeromagnetic maps. A key question is: Are the lineaments surface expressions of deformation zones? To answer this question, the interpreted lineaments were checked against the investigation trenches at the Olkiluoto site. Out of 61 method specific lineaments intersecting the investigation trenches, only 18 intersect the trenches in places with observed brittle fault or joint intersection. Using the lineament direction and the dip obtained from the observed faults or joints in the trench intersection, these 18 lineaments were modelled in 3D to check whether they could be connected to the brittle joint or fault intersections in the drillholes. The results were very contradictory. With the used dip direction and dip, lineaments intersect a variable amount of drillholes but only in a few of them at brittle fault or joint intersections could 385 APPENDIX VI be found (Table 1). Moreover, because of the location of the drillholes, only a few of them could possibly be connected to a lineament. Even if there was a matching intersection in the drillhole, its orientation based on the orientation of the faults, does not often match with the orientation of the lineament. However, four topographic and surface magnetic lineaments intersecting the investigation trenches could have been modelled as brittle fault zones (Table 2). Brittle fault zone OL-BFZ041, which has been modelled on the basis of drillhole data from seven drillholes, has been connected to the surface magnetic lineament and brittle fault intersection in OL-TK8. Brittle fault zone OL-BFZ067 modelled in drillhole OL-KR12 has been connected to the surface magnetic lineament intersecting investigation trench OL-TK4 at the location of the brittle fault intersection. Brittle fault zone OL-BFZ109 connects the surface magnetic and topographic lineament, brittle joint intersections in investigation trench OL-TK2 and brittle joint intersection drillhole OL-KR7. Brittle fault zone OL-BFZ110 connects the topographic lineament, brittle fault intersection in investigation trench OL-TK8 and brittle joint and fault intersections in drillholes OL-KR13 and OL-KR19. However, due to miss-match to the adjacent drillholes, the modelled brittle fault zones can not be as long as interpreted in the lineament interpretation (see Table 1).
Also all the brittle fault zones modelled on the basis of only the drillhole data have been checked against the lineament data but the correlation has been rather poor. Only brittle fault zones OL-BFZ099 and OL-BFZ106 could have been connected to the interpreted lineaments (Table 2).
The results of the comparison of the lineaments, trenches and the drillholes indicate that from all the method-specific lineaments, the surface magnetic lineaments are likely candidates for a brittle deformation zone. However, most of the interpreted lineaments, at least within the well-characterised area, seem to be features other than zones of brittle deformation. It can be speculated that at least part of the geophysical lineaments reflect the ductile deformation features (see Section 3.2.2) or lithological boundaries. Many of the NW-SE trending topographic lineaments may be due to glacial phenomena. The use of lineaments in the future modelling of the brittle deformation needs a thorough analysis, e.g., by targeted drilling, trenching, validated geophysics, and so on. Table 1. Lineaments intersecting the investigation trenches in places with observed brittle deformation intersection. The lineaments have been extended to boreholes using the dip from the intersections in the trenches. LINKED = linked lineament, SURFMAGN = surface magnetic lineament, TOPO = topographic lineament, GTKMGN = aeromagnetic lineament.
LINEAMENT LINEAMENT LINEAMENT STRUCTURAL INTERSECTION IN WIDTH DIP DIP DESCRIPTION CALCULATED OBSERVED STRUCTURAL REMARKS TREND LENGTH THE TRENCH IN THE DIRECTION (TRENCH) DRILLHOLE INTERSECTIONS IN THE TRENCH INTERSECTIONS DRILLHOLES LINKED 61 3354 BJI_OL-TK2_P25_260_P25_300 6.34 159 30 Fracture zone, KR10 70.84 OL_KR7_BJI_8265_8330 No structural 0474 BJI_OL-TK2_P25_990_P25_1010 in which the KR14 13.56 OL_KR30_BFI_8109_8348 intersections in (SURFMAGN BJI_OL-TK2_P25_1135_P25_1195 rock is in small KR24 233.79 OL_KR29_BJI_25147_25184 adjacent trench 0166, TOPO BJI_OL-TK2_P26_360_P26_686 fragments. KR28 270.43 TK4. 0118) KR29 233.06 Consequently, KR30 88.16 only KR4 195.15 intersections in KR7 78.98 KR7 and KR29 KR8 498.82 possible. Intersection in KR30 modelled
as OL-BFZ056 386 (120-150/10- 15°). SURFMAGN 175 299 BJI_OL-TK3_P10_240_P10_280 0.4 122 36 >20 fractures/40 KR19 137.12 No intersections 0049 cm in the KR20 50.18 MGN/PGR contact (122/36°) SURFMAGN 84 737 BFI_OL-TK3_P44_118_P44_128 0.1 254 83 3-10 cm wide Not calculated The lineament 0009 sinistral fault (see remarks). almost with 10-15 cm perpendicular apparent to the displacement observed fault! (254/83°) APPENDIX VI SURFMAGN 61 874 BFI_OL-TK4_P17_110_P17_200 0.9 155 80 An intensely KR1 16.27 OL_KR12_BFI_50500_50600 No structural 0012 fractured, KR12 510.28 OL_KR7_BFI_69410_70210 intersections in strongly KR14 317.87 adjacent trench weathered KR15 317.83 TK2. Modelled crushed fault KR7 694.00 as OL-BFZ067 zone with in KR12 with sinistral sense reduced length. of faulting.
SURFMAGN 177 250 BJI_OL-TK4_P27_805_P27_895 0.9 140 60 Migmatitic mica Not calculated The difference 0047 gneiss is slightly (see remarks). between the to strongly intersection weathered and and the intensely lineament is fractured along 53°! the foliation planes and the contacts of the granite
leucosome 387 veins. TOPO 0124 92 881 BJI_OL-TK4_P48_137_P48_297 1.6 180 85 Ca. 1.6 m wide KR7 252.65 OL_KR25_BFI_34700_35225 Intersection in fracture zone in KR25 337.94 KR25 part of the mica gneiss, KR28 482.51 site-scale fault A completely KR4 519.31 zone OL- weathered, 80 BFZ098 cm wide zone in oriented the contact 155/20°. between the mica gneiss and the granite pegmatite. APPENDIX VI SURFMAGN 62 1572 BJI_OL-TK4_P58_520_P58_870 3.9 140 50 Strongly KR22 175.02 OL_KR22_BFI_18845_20050 No structural 0167 BJI_OL-TK4_P58_965_P58_1098 weathered KR24 150.41 OL_KR25_BJI_9445_9730 intersection in migmatite has KR25 90.93 KR27 OL_KR27_BFI_42709_43342 KR28. intensely broken 439.52 KR28 OL_KR4_BFI_8154_8239 Consequently, along the 206.10 KR29 only foliation planes 138.61 KR4 85.70 intersections in or narrow KR9 296.72 PH2 KR22, KR25 biotite-rich 108.55 ONKALO and KR27 melanosome 240.89 possible. The schlieren intersection in between the KR22 modelled granite veins. as OL-BFZ060 (127/32°), in KR25 as OL- BFZ055 (138/78°) and in KR4 as OL- BFZ018 (139/15°). SURFMAGN 121 821 BJI_OL-TK4_P76_1030_P78_590 10.1 In P76, the Does not intersect Local
0170 diatexite is the drillholes. weathering in 388 strongly OL-TK4. weathered and broken into small fragments. In places, the rock is totally weathered into a clayey mass. In P77, the diatexite is less weathered than before and composed of blocks of rocks, ranging from 1 m3 to 2.5 m3. Between the blocks, there is APPENDIX VI either wide, open fractures or strongly weathered rock, which is broken to small fragments.
SURFMAGN 48 502 BFI_OL-TK7_P8_347_P8_400 0.53 85 75 Brittle fault zone Not calculated OL-BFZ100. 0011 with calcite and (see remarks). The difference chlorite coated in orientation fractures between the oriented ca. intersection 085/75° and the 389 lineament is 53°! SURFMAGN 1 693 BJI_OL-TK7_P17_263_P17_315 0.62 255 77 A narrow No intersections. 0115 fractured zone with four tight fractures steeply dipping to the WSW. APPENDIX VI LINKED 99 9683 BFI_OL-TK8_P52_075_P52_155 0.8 171 58 A sheared KR1 717.71 OL_KR12_BFI_58240_58410 No structural 0145 (TOPO intersection KR11 261.25 OL_KR13_BFI_40941_42389 intersections in 0128 containing 15 KR12 577.74 OL_KR19_BFI_9945_10309 adjacent trench GTKMAGN fractures, KR13 386.72 OL_KR20_BJI_46362_47071 TK9. No 0174) several of them KR19 99.52 OL_KR21_BFI_27577_28100 structural with slickenside KR2 412.69 intersection in surface. KR20 488.83 KR2. KR21 269.63 Consequently, KR33 230.26 only KR5 204.38 intersections in KR13, KR19, KR20 and KR21 possible. Intersection in KR12 modelled as OL-BFZ094 (117/74°), in KR13 as OL- BFZ045 (101/67°), in KR19 as OL- BFZ044 390 (144/37°), KR21 as OL- BFZ005 (165/34°) and KR20 as OL- BFZ065 (099/38°). LINKED 74 937 BJI_OL-TK8_P20_285_P20_837 5.48 168 35 Intersection of KR1 172.37 KR10 OL_KR12_DSI_14400_15054 No structural 0261 (TOPO weathered, 310.04 KR12 OL_KR13_BJI_3385_4604 intersection in 0125) sheared and 149.57 KR13 OL_KR14_BFI_21755_21913 KR2. crushed rock. 53.12 KR14 OL_KR20B_BJI_3950_4215 Consequently, The zone is 212.04 KR15 only approx. 5.5 m 192.89 KR2 96.69 intersections in wide and shows KR20 37.00 KR13 and a ca. 3 m thick KR20B 39.61 KR20 possible. regolith on both KR24 525.32 Intersection in sides of the pit. KR28 500.55 KR13 is part of APPENDIX VI KR29 517.80 OL-BFZ008 KR32 69.25KR4 (157/10°). 440.35KR7 343.54 SURFMAGN 62 530 BJI_OL-TK8_P150_510_P150_661 1.51 1 75 The contact Does not intersect 0024 between the the drillholes. grey gneiss and granite pegmatite is intensely fractured.
SURFMAGN 90 347 BFI_OL-TK8_P126_223_P126_353 1.3 192 82 An E-W trending KR6 250.87 No intersections 0054 intersection striking parallel to the foliation. It is 1.3 m wide and the rock is very soft and strongly sheared. SURFMAGN 84 2152 BFI_OL-TK8_P27_197_P27_257 1.4 192 80 The intersection KR1 815.10 OL_KR13_BFI_36275_37446 Subhorizontal 0157 is in the contact KR11 483.97 (086/12°) between the KR13 384.99 fracture zone 391 granite KR2 524.15 (15 cm) parallel pegmatite and KR20 330.59 to the foliation diatexitic gneiss. KR21 73.75 in OL-TK13. Intersection in KR13 modelled as OL-BFZ028 (268/82°) and OL-BFZ092 (109/40°). LINKED 136 6072 BJI_OL-TK8_P43_113_P43_148 0.35 57 85 The intersection KR2 844.32 No intersections 0122 (TOPO is slightly KR12 619.49 0472, brecciated and GTKMAGN contains quartz, 0015 ) chlorite and epidote. APPENDIX VI LINKED 107 3131 BJI_OL-TK8_P71_130_P71_250 1.2 210 40 An intersection KR1 557.1 OL_KR13_BFI_27840_28810 No structural 0317 (TOPO BJI_OL-TK8_P75_204_P75_280? with altered and KR13 296.41 OL_KR14_BFI_44500_44908 intersection in 0074) crushed rock KR14 439.82 OL_KR15_BFI_49350_49650 KR2 and KR5. striking parallel KR15 475.71 OL_KR19_BJI_12263_12492 Consequently, to the foliation. KR19 130.86 OL_KR20_BFI_42690_43114 only KR2 305.12 OL_KR33_BFI_28678_28815 intersections in KR20 433.58 KR13, KR19 KR21 297.82 and KR20 KR33 297.09 possible. KR5 231.65 Intersection in KR7 687.22 KR20 belongs to site-scale structure OL- BFZ099 (160- 170/30-40°). LINKED 119 2344 BFI_OL-TK8_P126_223_P126_353 1.3 192 82 An E-W trending KR6 201.37 OL_KR6_DSI_20470_21666 HSP-reflectors 0208 (TOPO intersection HSP3_19 0070) parallel to the (203/80°) and foliation. It is 1.3 HSP3-20 m wide and the (225/60°)
rock is very soft 392 and strongly sheared. APPENDIX VI 393 APPENDIX VI Table 2. Modelled fault zones connecting lineaments, trench intersections and drillhole intersections.
LINEAMENT TRENCH INTERSECTION DRILLHOLE INTERSECTION DIP DIP MODELLED DIR FAULT ZONE SURFMAGN BJI_OL- OL_KR13_BFI_16378_17647 156 31 OL-BFZ041 0051 TK8_P86_300_P86_510 OL_KR6_BFI_480_1395 OL_KR19B_BFI_4045_4505 OL_KR32_BJI_17526_17678 OL-KR41 213.45-214.55 RiIII OL-KR42 310.01-314.15 RIIII OL-KR42 314.15-315.57 RiIV
SURFMAGN BFI_OL- OL_KR12_BFI_50500_50600 150 45OL-BFZ067 0012 TK4_P17_110_P17_200 LINKED 0255 No intersections OL_KR4_ BFI_75770_762.70 165 40 OL-BFZ099 (TOPO 0069 & OL_KR1_ BFI_525.20_526.20 0076, OL_KR1_ BFI_538.60_539.63 GTKMAGN0126)) OL_KR2_ BFI_47100_47235, OL_KR2_DSI_46749_47380 OL_KR3_ BJI_47050_47140, OL_KR3_DSI_47070_47290 OL_KR6_ BFI_12322_12945 OL_KR6_ BFI_11753_11805 OL_KR7_ BFI_68990_69200 OL_KR7_ BFI_69410_70210 OL_KR19_ BFI_25335_25982, OL_KR19_BJI_23839_25860 OL_KR33_ BFI_27591_28043 OL_KR33_ BFI_28678_28815 OL_KR43 100 - 101 OL_KR13 BFI__44550_46800 OL_KR13_ BFI_47500_48052 OL_KR20 BFI__41059_42445 OL_KR20_ BFI_42690_43114 OL_KR13 BFI__58240_58410 OL_KR5 BFI__26945_27085 OL_KR5_ BFI_27897_28244 OL_KR11 BFI__62502_62647 OL_KR29_ BFI_74570_74730 OL_KR29_ BFI_77651_78102, OL_KR29_BJI_76280_76365
LINKED 0582 No intersections OL_KR22_BFI_4280_7315 057 48 OL-BFZ106 (SURFMAGN OL_KR27_BFI_12816_12960 0173, TOPO O126, SEISMIC0048) LINKED 0474 BJI_OL- OL_KR7_BJI_8265_8330 OL_KR29_BJI_25147_25184 159 30 OL-BFZ109 (SURFMAGN TK2_P25_260_P25_300 0166, TOPO BJI_OL- 0118) TK2_P25_990_P25_1010 BJI_OL- TK2_P25_1135_P25_1195 BJI_OL- TK2_P26_360_P26_686 LINKED 0317 BJI_OL- OL_KR13_BFI_27840_28810 OL_KR19_BJI_12263_12492 210 40 OL-BFZ110 (TOPO 0074) TK8_P71_130_P71_250 BJI_OL- TK8_P75_204_P75_280? 394 395 APPENDIX VII
ID OL-BFZ099
Dimensions 2600 m in E-W direction 1700 m in N-S direction Description OL-BFZ099 is a gently dipping, medium angle thrust fault, with an approximate dip of 40 degrees towards SE and modelled trace length of 2700 m in E-W-direction and 1700 m in N-S-direction. The fault zone is geologically pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, alteration and varying amounts of incohesive fault breccias and gouges (i.e. crushed rock). According to the RG-classification system, the core consists of RiIII, RiIV and RiV-sections, i.e. densely fractured sections (RiIII), clay- filled sections (RiIV) and clay structures (RiV). The widths of fault core intersections of the zone vary from 1 to 13 meters, the average width being 4.9 meters. A majority of the core intersections fall into the RiIII-category of the RG- classification, but in few intersections also RiIV and RiV-sections occur. This corresponds to the variation on the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone also shows recurrent movement, in addition to ductile precursors, as shown in many drillcore intersections by reactivated cataclasites.
The width of the influence zone of OL-BFZ099 is in average 44.3 m but varies from a maximum of 103 m (KR20) to a minimum of 11 m (KR29). The characteristic features of the influence zone are the abundance of slickensides, pervasive illitisation, kaolinisation and sporadical fracture-controlled sulphidisation and, in many cases, subsidiary core sections. In most cases, the existence of slickensides has been the limiting criteria for the definition of the influence zone, although a clear increase in fracture frequency is also a characteristic property of the zone. However, in drillholes KR11 and KR20 only very few slickensides exist and KR29 is an exception, as there are no slickensided fractures. The location of KR29 is furthest to the south and it is possible to argument whether this zone continues there or are we at the tip of the zone, represented by abundant fracturing corresponding to horsetail splay or similar structure. In most drill hole intersections the zone has an increased hydraulic conductivity, mainly in or close to the core sections. However, hydraulic conductivity is not a characteristic feature for this zone. The main rock type of zone is usually veined gneiss and pegmatitic granite. In many cases the core sections are at or close to the contact of these rock types.
The average width of the hanging wall influence zone is 16 m, the highest values being at drill holes KR29, KR1, KR31 and KR5. KR29 was the most southern borehole, a possible tip area, and rest of the boreholes are located at the north- western part of the investigation area. The average width of the footwall influence zone is 23.1 meters. In general, the footwall influence zone is somewhat wider than the hanging wall’s. 396 APPENDIX VII
Geometry of the Gently dipping, medium angle thrust fault with a dip direction/dip of approximately zone 174/34
Core OL-KR1 524-526.20 OL-KR19 253-261 intersections OL-KR2 471-473 OL-KR20 416-429 OL-KR3 470-473 OL-KR29 777-781 OL-KR4 756-764 OL-KR33 275.50-279.00 OL-KR5 278-283 OL-KR43 100-101 OL-KR6 124-129 OL-KR7 690.50-692.02 OL-KR11 623-627 OL-KR12 581-584 OL-KR13 450-460
Zone of OL-KR1 490-545 OL-KR19 230-265 influence OL-KR2 458-493 OL-KR20 402,5-438 intersections OL-KR3 462.5-474 OL-KR29 743-786 OL-KR4 750-820 OL-KR33 266-305 OL-KR5 249-304 OL-KR6 93-144 OL-KR7 685-724 OL-KR11 615-650 OL-KR12 561,5-602,5 OL-KR13 440-498 Applied data Mise-á-la-masse Earthing OL-KR4 Connection OL-KR1 527, OL-KR2 470, OL- 759 to KR3 465-475, OL-KR6 120, OL- KR19 240, OL-KR33 278, OL- KR43 100 3D-seismics Juhlin & Cosma (2007) Gefinex Jokinen & Lehtimäki (2004) Confidence High (3) Class of the zone Site-scale deformation zone
Comparison to Updated version of OL-BFZ099 presented in the Geological Site model v.0 geological Site (Paulamäki et al. 2006) model v. 0 Updates - Updated, version 1.0 version history Compilation 22.11.2007 date and Jussi Mattila & Liisa Wikström compiled by 397 APPENDIX VII
ID OL-BFZ002
Dimensions 2600 m in E-W direction 1700 m in N-S direction Description OL-BFZ002 is a gently dipping, low angle thrust fault, with an approximate dip of 30 degrees towards SE and modelled trace length of 2400 m in E-W-direction and 1300 m in N-S-direction. OL-BFZ002 and OL-BFZ099 are considered as two splays of a one single zone, and they combine into a single zone at the central part of the Site volume. Similarly to OL-BFZ099, OL-BFZ002 is geologically pronounced, the fault core being well-developed and characterised by abundant fracturing, clay-filled fractures and slickensides, alteration and varying amounts of incohesive fault breccias and gouges (i.e. crushed rock). According to the RG-classification system (Gardemeister et al. 1976), the core consists of RiIII, RiIV and RiV-sections, i.e. densely fractured sections (RiIII), clay-filled sections (RiIV) and clay structures (RiV). The thicknesss of fault core intersections of the zone vary from 1 to 8 meters, the average thickness being 4.5 meters. As for the OL-BFZ099, majority of the core intersections fall into the RiIII-category of the RG-classification, but in few intersections also RiIV and RiV-sections occur, mainly in the central part of the investigation area. Again, this corresponds to the variation on the relative proportions of fault breccia and fault gouge, fault breccia being the most common type of fault rock. The zone also shows recurrent movement, in addition to ductile precursors, as shown in many drillcore intersections by reactivated old and welded fractures and cohesive breccias.
The width of the influence zone BFZ002 is in average 43.5 m but varies maximum being 75 m (KR2) and minimum being 11 m (KR29). The width of the main core is in average 4,5 m. The average width (the intersection length at the drill hole) of the upper influence zone is 16.2 m and the average width of the lower influence zone is 22.7 m. In general the upper influence zone is somewhat wider than the lower one. One reason probably is that in some places the two separate splays have in fact one larger connected influence zone.
The fault system forms two splays at the northern part of the island but conjoin to form one fault between boreholes KR2 and KR12 (two separate) respective KR4 and KR7 (one fault), i.e. in the middle of the island. The influence zones are difficult to separate at around KR2 and KR12 and as a consequence they are quite large at this point. Furthermore, in both cases the separation of influence zones appeared to be quite artificial.
The modelled zone seems to be located close by or at the contact between the gneisses and larger pegmatitic granite body, at least in the central part of the island. In many intersections right at the modelled influence zone the rock type is varying between pegmatitic granite and gneisses. In KR12 the whole zone, including both splays, is located under the large tonalitic gneiss. However, in KR5 and KR11 no such rock type contact is seen but the whole zone is located at the gneiss.
The characteristics for this influence zone are the abundance of slickensided fractures, pervasive illitisation and in all cases more than one core section. The existence of slickensided fractures has been the limiting criteria for the influence 398 APPENDIX VII zone. Also the clear increase in fracturing seems to describe the zone. However, in KR11 only very few slickensided fractures exists and KR29 is an exception with no slickensided fratures. The location of KR29 is furthest south and it can be discussed does this zone continue there or are we at the tip of the zone and there is only fracturing, like horsetail splay, connecting it to the rest of the zone. Also KR11 is located quite far in the north-eastern corner of the investigation area and it can be discussed if the characteristics of this zone are less prominent at that location.
Alteration is also a characteristic feature describing this zone. It appears either as pervasive illitisation in the host rock around the core or abundant fracture-controlled kaolinisation, illitisation and in some intersections also sulphidisation. In KR12 the pervasive illitisation continues further up to the upper splay, but the influence zone has been limited based on lesser fracturing and especially only single slickensided fractures between the influence zones at 590 – 630 m. However, as mentioned earlier this is very artificial limit and the influence zone could continue here to combine both splays if defining it primary based on alteration.
Usually this zone has increased hydraulic conductivity mainly at or close to core sections, but in most intersections also single water conductive features are met in the influence zone, especially in places with pervasive alteration. KR11 and KR3 are exceptions being slightly conductive only at the core.
The geophysical anomalies, the acoustic long normal and short normal, are used to characterise and define this zone. In many cases they seem to describe the influence zone as well as core sections. One probable reason for this could be difference in porosity in the altered sections, which might be explanation for the description of the influence zone.
The intersection of KR3 is quite special case in many ways. It has very narrow influence zone (11,5 m) based on slickensided fractures, which has been the special feature for this modelled zone, and used in defining the limits for the influence zone. However, based on pervasive illitisation the influence zone could be from 420 to 502, i.e. altogether 82 meters, which would be the second largest influence zone for the modelled BFZ002. Reason for not to use the alteration as a limiting characteristric is that it is met in many boreholes, but not in all of them, and for this reason is handled more like a second important character together with hydraulic conductivity, while slickensided fractures are the primary character for this zone.
Another drill hole intersections for this zone with narrow influence zone are KR29 (the southernmost drill hole described earlier) and KR11 (35 m), rest of the influence zones are over 30 m. This has probably something to do with the location of the drill hole being furthers away in northeast. Though, based on one drill hole no definite conclusions about the characteristics of this major zone in the eastern part of the island cannot be made. 399 APPENDIX VII
Geometry of the A gently dipping, low angle thrust fault with an approximate dip direction/dip of zone 20/160
Core OL-KR1 611-618 OL-KR43 340-341 intersections OL-KR2 600-607 OL-KR3 470-473 OL-KR4 756-764 OL-KR5 481-483.5 OL-KR6 468-471 OL-KR7 690.50-692.02 OL-KR11 623-627 OL-KR12 665-673 OL-KR19 464-466 OL-KR29 777-781 Influence zone OL-KR1 593-649 OL-KR29 775-786 intersections OL-KR2 568-643 OL-KR43 not defined, no data OL-KR3 462,5-474 OL-KR4 750-820 OL-KR5 460-510 OL-KR6 435-479,5 OL-KR7 685-724 OL-KR11 615-650 OL-KR12 643,5-675,5 OL-KR19 440-494 Applied data Mise-á-la-masse Earthing OL-KR4 Connection OL-KR1 527, OL-KR2 470, OL- 759 to KR3 465-475, OL-KR6 120, OL-KR19 240, OL-KR33 278, OL-KR43 100 3D-seismics Juhlin & Cosma (2007) Gefinex Jokinen & Lehtimäki (2004) Confidence High (3) Class of the zone Site-scale deformation zone
Comparison to Updated version of OL-BFZ002 presented in the Geological Site model v.0 geological Site (Paulamäki et al. 2006) model v. 0 Updates - Updated, version 1.0 version history Compilation 22.11.2007 date and Jussi Mattila & Liisa Wikström compiled by 400 APPENDIX VII
ID OL-BFZ056
Dimensions 930 m in E-W direction 750 m in N-S direction Description Gently dipping thrust fault with an approximate dip of c. 10 - 15 degrees towards SSE. The fault is located just some tens of meters below fault OL-BFZ018 and is subparallel to it. The core of the fault is 0,1 – 1,4 m thick with increased fracturing and slickenside fractures. The core zone is also frequently hydraulically conducting. Alteration data related to this zone indicates fracture-controlled kaolinisation, illitisation and sulphidisation. Occasionally, illitisation is also pervasive. The fault is intersected by 21 drillholes. The core is characterized by brittle fault intersections, RiIII-IV-sections or core loss in 13 drillholes. In 8 drillholes (OL-KR2, OL-KR10, OL-KR12, OL-KR14, OL-KR25, OL-KR37, OL-KR9 and OL-KR4) significant geological evidences are lacking, however the fault is delineated to them according to its general geometry, geophysical and/or hydraulic results. Geophysically, the fault can be observed frequently as a P-wave minimum and an electric conductor. Geometry of the fault is based mainly on combining Mise-a-la-masse results to geological observations in the drillholes and in the ONKALO tunnel.
The fault intersects the ONKALO tunnel with an oblique angle at chainage c. 1045 m related to a brittle fault intersection ONK-BFI-104500-110850. The core of the zone is 10-20 cm wide and consists of a main fracture/fault that can be followed in both tunnel walls. The affected zone is over 5 m wide though, consisting of conjugate fractures. The main fracture is hydraulically conductive. Within the whole intersection (1045 – 1108.5 m), there are many other long and sub-horizontal fractures in the zone and several shorter vertical fractures that join the horizontal ones.
The BFZ056 (R19C) is located in the lower part of the “surface bedrock”. Above the zone rock is often clearly more fractured and the hydraulical measurements shows almost a continuously hydraulically conductivity. Underneath this zone rock becomes less fractured and hydraulically conductive. This phenomenon is valid especially for the ONKALO area of the zone (drill holes OL-KR4, OL-KR14, OL- KR22, OL-KR23, OL-KR25, OL-KR28, OL-KR31, KR36, OL-KR38). Probably because of this phenomenom the lower limit for the influence zone was usually easier to define than the upper limit.
This modelled zone has many drill hole intersections, total 21, but only 18 of them have been considered in the description of the influence zone because there was some part of the data missing in the dismissed drill holes. The width of the influence zone of BFZ056 is in average 16 m but varies maximum being 40 m (KR11) and minimum being 4 m (KR24 and PH5). In general the lower influence zone is somewhat wider than the upper one. Commonly the whole influence zone is wider in the eastern part of the investigation area (KR11, KR9, KR27 and KR31 and KR22) than in the central part of the investigation area above the ONKALO.
The modelled zone seems to be located mainly at the diatexitic or veined gneiss, but in few places the modelled main core section is located at the contact between either of gneisses and pegmatitic granite bodies.
The main defining characteristic for this influence zone is elevated hydrological conductivity both at the core and in the influence zone. Some of the drill hole 401 APPENDIX VII intersections are geologically clear zone intersections and some are geologically insignificant, but have a clearly elevated hydraulic conductivity, like KR4, KR14 and KR37. In five drill holes, KR4, KR9, KR31, KR37 and KR38, the hydraulic conductivity is not only concentrated on the core sections but distributed along the whole influence zone. Usually the highest hydraulic conductivity is at the core sections and close by in the influence zone. In addition also altered sections have often elevated hydraulic conductivity compared to the unaltered rock.
Alteration in this zone appears as all types of alteration from fracture alteration to pervasive alteration. The most altered drill holes are KR11 (pervasive illitisation and kaolinisation), KR22 (pervasive sulphidisation and fracture kaolinisation), KR30 (pervasive kaolinisation and fracture illitisation, KR36 (pervasive sulphidisation and fracture illitisation) and KR27 (pervasive illitisation). Drill holes KR11, KR22 and KR27 represent the eastern part of the well-investigated area and KR30 and KR36 are located on the central investigation area above the ONKALO volume. However, the most common feature is no alteration at the drill hole intersections (KR4, KR14, KR24, KR25, KR28, KR31 and KR37) of this zone in the central part above the ONKALO area.
A slight increase in fracturing is clear in every drill hole along this zone, but mainly significant increase in fracturing is seen only around the core sections. Slickensided fractures are met in all other drill holes except KR4, KR23 and KR30, i.e. in some drill holes in the central part of the area. The slickensided fractures are in most cases concentrated close to the core sections, though single ones can be found in the whole influence zone.
The geophysical anomalies, the acoustic long normal and short normal minimum and single point resistance minimum are very important tools to define this influence zone. In most cases they seem to describe the whole defined influence zone. The P- wave velocity is mainly describing the core sections.
Generally, based on geological core logging, the drill hole intersections represent brittle deformation zone and in one drill hole, KR4, high-grade shear zone intersection has been met. Based on rock engineering classification these intersections are usually classified as RiIII-sections, but in two drill holes, KR11 and KR36, also RiIV-sections are met.
It is kept in mind that the defined intersections in KR10, KR11 and KR12 are very close to the surface and for this reason some part of data is missing and can also be misinterpreted.
The influence zone in drill hole KR27 is especially difficult to define because of continuously increased fracturing, existence of slickensided fractures and many core section in this part of the drill hole. This is probably an effect of the modelled vertical zones in this area and makes the definition of influence zone uncertain. However, the orientation of fracturing has been taken into account while defining the zone. 402 APPENDIX VII
Geometry of the Gently dipping semiplanar feature. Dip direction/dip c. 150/10-15. zone
Core OL-KR2 24.54 - 25.75 OL-KR30 82.5-83.2 intersections OL-KR10 76.5 - 77 OL-KR31 174.6-175.4 OL-KR11 114.2-115.5 OL-KR36 154.7-155.9 OL-KR12 39.1 - 40.5 OL-KR37 168 - 169 OL-KR14 50 - 51 OL-KR38 122.22 - 122.54 OL-KR22 144.9-145.6 OL-KR9 197-198 OL-KR23 195.3-196.1 OL-KR40 283.73 - 284.78 OL-KR24 115.3-115.8 OL-KR42 57.7-58.18 OL-KR25 119 - 120 OL-KR4 116.1 - 116.3 OL-KR27 283.0-283.5 ONK-PH5 57.09 - 57.2 OL-KR28 172.6-172.7 ONKALO 1045.4 – 1045.7 Zone of OL-KR2 Not determined OL-KR30 80-92,5 influence OL-KR10 73-89 OL-KR31 163-179,5 intersections OL-KR11 104-144 OL-KR36 152-162,5 OL-KR12 Not determined OL-KR37 167,5-176 OL-KR14 47.5-56 OL-KR38 112-126 OL-KR22 136,5-162,5 OL-KR9 196.5-228 OL-KR23 192,5-207,5 OL-KR40 266-287 OL-KR24 112,5-116,5 OL-KR42 Not determined OL-KR25 112,5-125,5 OL-KR4 108-117,5 OL-KR27 274-296,5 ONK-PH5 56-60 OL-KR28 170-185 Applied data Mise-á-la-masse Earthing KR4 80 KR23 220
KR25 122 KR23 220 KR27 250-305 KR28 180
KR28 179 KR24 134 3D-seismics Juhlin & Cosma (2007) Gefinex
Gently dipping conductors Paananen et al. 2006 nearby Confidence High (3) Class of the zone Site-scale deformation zone
Comparison to Updated version of OL-BFZ056 presented in the Geological Site model v.0 geological Site (Paulamäki et al. 2006) model v. 0 Updates - Updated, version 1.0 version history Compilation 16.11.2007 date and Markku Paananen & Liisa Wikström compiled by 403 APPENDIX VII
ID OL-BFZ018
Dimensions 1300 m in E-W direction 700 m in N-S direction Description Gently dipping thrust fault with an approximate dip of c. 15 degrees towards SE. The core of the fault is 0.1 – 4 m thick with increased fracturing and occasional slickenside fractures. The fault is located just some tens of meters above fault OL- BFZ056 and is subparallel to it. Alteration data related to this zone is rather contradictory, however, mostly fracture-controlled kaolinisation, illitisation and sulphidisation is observed. In places, the alteration is also pervasive. The fault is intersected by 20 drillholes. The core is characterized by brittle fault intersections or RiIII-IV-sections in 14 drillholes. In 6 drillholes (KR14, KR23, KR28, KR31, KR35 and KR36) significant geological evidences are lacking, however the fault is delineated to them according to its general geometry and geophysical results. In most drillholes, the core of the fault is also hydraulically conducting. Geophysically, the fault can be observed frequently as a P-wave minimum and an electric conductor. Geometry of the fault is based mainly on combining Mise-a-la-masse and VSP results to geological observations in the drillholes.
In the ONKALO tunnel, the fault can be observed at the chainage of c. 950 – 963 m, related to a long brittle fault intersection, located at 931.90 – 963.00 m. The intersection angle between the fault and the tunnel is rather oblique. The fault intersection is undulating, slickensided and contains 3-40 cm thick fillings of chlorite, clay, pyrite, calcite, graphite, and kaolinite. In the thickest parts, the filling contains some broken rock fragments and thick clay fillings. The fault is also hydraulically conductive.
No influence zone has been determined for this zone.
Geometry of the Gently dipping semiplanar feature, dip direction/dip c. 140/15. zone Core OL-KR11 114.20-115.50 OL-KR36 94 - 95 intersections OL-KR14 12-16 OL-KR37 123.3-123.8 OL-KR22 109-112 OL-KR38 88.1-88.7 OL-KR23 136 - 137 OL-KR4 81.5-82.4 OL-KR24 93.5 - 95 OL-KR7 19 – 20 OL-KR25 96-97 OL-KR8 121.25-121.35 OL-KR27 261.4-261.6 OL-KR9 149.0 - 149.3 OL-KR28 154.5 - 155.5 OL-KR40 273.87 - 273.96 OL-KR31 144 - 144.4 ONK-PH4 85.53 - 85.68 OL-KR34 78.3-78.8 ONKALO 952.9 – 954 OL-KR35 93.5 - 94.5 Zone of Not determined influence intersections Applied data Mise-á-la-masse Earthing OL-KR4 80 Connection OL-KR22 150,OL-KR28 155, to OL-KR24 90
OL-KR8 162 OL-KR22 75-160
OL-KR25 122 OL-KR27 250
OL-KR27 262 OL-KR40 290 404 APPENDIX VII
3D-seismics Juhlin & Cosma (2007) Gefinex
Gently dipping conductors Paananen et al. 2006 nearby Confidence High (3) Class of the Site-scale deformation zone zone Comparison to Updated version of OL-BFZ018 presented in the Geological Site model v.0 geological Site (Paulamäki et al. 2006) model v. 0 Updates - Updated, version 1.0 version history Compilation 16.5.2007 date and Markku Paananen compiled by 405 APPENDIX VII
ID OL-BFZ080
Dimensions 1290 m in NE-SW direction 1175 m in NW-SE direction Description Gently dipping thrust fault with an approximate dip of c. 20 degrees towards SE. It is located only some tens of meters below another site-scale subparallel fault zone OL- BFZ098. The core of the fault is 0.2 – 8.58 m thick, with a typical thickness of c. 1 m. The fault is intersected by 21 drillholes, and in 9 drillholes a previously determined geological intersection (BFI or BJI) was associated with the zone. According to the RG-classification system, the core consists of densely fractured sections (RiIII) and clay-filled sections (RiIV) in most of the intersecting drillholes. Hydraulic conductivity is often also elevated. In three drillholes (KR1, KR13 and KR15) there are no clear geological indications of a deformation zone at the intersections. However, according to geophysical and hydraulic results, slickensided fractures and the general geometry of the fault, it has been delineated also to these drillholes. Based on Sampo Gefinex results, fault pair OL-BFZ098 and OL-BFZ089 may extend farther in the NW, at least to KR3. This continuation is now indicated as a separate fault OL-BFZ040.
There are not many indications of hydrothermal alteration related to the core of this fault. Kaolinisation is most common (pervasive as well as fracture-controlled). Furthermore, there is occasional illitisation and sulphidisation. Geophysically, the zone is observed in several drillholes as a P-wave minimum and an electric conductor. Its geometry is strongly based on Mise-a-la-Masse and Sampo Gefinex results and several VSP reflectors. The seismic reflectors detected from the ground surface are strongly concentrated to the upper fault zone OL-BFZ098.
There are no tunnel observations of this fault zone yet. Based on the modelled geometry, the fault would intersect the tunnel at chainage c. 3290 – 3293 m.
The BFZ080 seems to form a lower part of the double-sided fault system together with the zone BFZ098, and the separation of influence zones between BFZ098 and BFZ080 appeared to be quite artificial in many places.
This modelled zone has totally 21 drill hole intersections, but only 20 of them have been considered in the description of the influence zone because the newest drill hole intersection KR42 has not yet been logged similarly as older drill holes to be included here. The width of the BFZ080 influence zone is in average 30.25 m but varies maximum being 82 m (KR13) and minimum being 7.5 m (KR14). The width of the main core is in average 2 m. The average width (the intersection length at the drill hole) of the upper influence zone is 12.3 m and the lower influence zone is 16.4 m. In general the lower influence zone is somewhat wider than the upper one.
The modelled zone seems to be located only in few drill hole intersections, at KR25, KR27 and KR28, entirely at one rock type, i.e. at veined gneiss. In most cases it is located in the contact of gneiss respective large body of pegmatitic granite and in many cases the rock types are varying intensively in the contact area.
The main defining characteristic for this influence zone is the hydrological conductivity both at the core and in the influence zone. The highest values are usually in the core section, but clearly elevated values are seen in the influence zone 406 APPENDIX VII as well. A special case is KR8 where there is no hydrological conductivity at the most crushed section (RiIV), but conductivity is concentrated more or less into the RiIII-classified sections around the main core. Furthermore, only minor elevation or no hydraulic conductivity at the core section at KR12, KR15, KR27, KR39 and KR40 is met. These sections have still been interpreted to belong to this zone mainly based on geometry and other properties of the zone. The modelled intersection at KR27 is located at the end of the drill hole and the zone seems to continue further and reasoning has been that it can be conductive further down.
KR8 is a special case in other respect as well, the TDS-value seems to clearly increase at the core section in 550 m. The same phenomenom is met also in KR29 and KR38. Vice versa, in KR4, the measured TDS-value decreases back to the normal level in the influence zone of BFZ080. The increase in the same drill hole was detected in the upper zone BFZ098.
The geophysical anomalies, the acoustic long normal and short normal minimum, are very important tools to define this influence zone. In most cases they seem to describe the influence zone together with the hydraulic conductivity while the fracturing has been decreasing and there is no other significant features identifiable. In general the geophysical anomalies are often very continuous covering also the upper zone BFZ098. In those cases the upper limit for the influence zone has been artificially cut.
Alteration is also a characteristic feature describing this zone. It appears either as pervasive kaolinisation (KR1, KR2), illitisation (KR4, KR8, KR10, KR38, KR39) or sulphidisation (KR39) around the core or abundant fracture controlled kaolinisation and sulphidisation. Alteration is not met at all in KR14, KR24, KR25, KR27 and KR39. In few cases, like in KR1, alteration has been the main characteristic of the zone and defines the influence zone.
The increase in fracturing has not been as clear phenomenon in this zone as it is in BFZ002 and BFZ099, but in many boreholes it is more prominent than in BFZ098. However, a clear increase in fracturing may describe part of the influence zone in certain drill holes (KR7, KR9 and KR38), but it cannot be taken as a defining factor because it is not always distinctive for this zone. In some drill holes fracturing increases only slightly compared to averagely fractured rock mass. In addition, often the more fractured part of the intersection is concentrated very closely around the core, but still the alteration or hydraulically conductive fractures for instance continue further and the influence zone limit is defined based on them. Also amount of shear fractures, i.e. the slickensided fractures, is not increased as clearly characteristically as it is for the BFZ099 and BFZ002, however. The slickensided fractures are in most cases concentrated close to the core sections, though certain intersections have been defined based on their abundance. The very special cases are intersections at KR1 and KR38 without any mapped slickensided fractures.
The main type of intersections based on Ri-classification is RiIII. In addition, RiIV- class intersection can be found in 6 of 20 intersections (KR7, KR8, KR29, KR38, KR39 and KR40). For this modelled zone only drill hole intersection at KR38 has a short section, which belongs to class RiV. In addition, the modelled intersection at KR1 and KR15 has no core section defined. It is interpreted that this zone has not gone through as much movement neither has been exposed to as much strain as 407 APPENDIX VII
BFZ099 and BFZ002.
Generally, the geological logging has described the zone to be either brittle fault zone intersection or brittle joint zone intersection, but in one drill hole intersections, in KR13, a semi-brittle deformation zone intersection and in KR2 and KR12 a high- grade ductile deformation zone intersection has been mapped in addition to brittle fault zone and brittle joint zone intersections. At the modelled intersection in KR23 and KR27 no geological core section has been defined.
As a whole the intersection at KR14, in the central part of the investigation area, seems to be minor and quite insignificant with very little hydraulic conductivity and very few fractures. Instead, the intersection at KR29 and KR38 are significant based on existence of RiIV-classified core section in addition to many RiIII-sections, clearly increasing fracturing and elevated hydraulic conductivity. In KR29 (the southern most drill hole) also increased number of shear fractures exists.
Geometry of the zone Gently dipping semiplanar feature, dip direction/dip c. 140/20.
Core OL-KR1 176.3-177.4 OL-KR29 336.5-336.7 intersections OL-KR2 208.31-208.92 OL-KR38 383.5-384.8 OL-KR10 326.0-326.4 OL-KR39 178.94-187.52 OL-KR12 271.87 - 272.97 OL-KR4 370.1-370.6 OL-KR13 189.3-189.8 OL-KR40 630.4-631.2 OL-KR14 217.55 - 219.13 OL-KR7 285.7-287.8 OL-KR15 201.1-202.44 OL-KR8 552.8-555.3 OL-KR22 423.9-425.3 OL-KR9 473.7-474.9 OL-KR24 397.0-397.9 OL-KR42 272.83-279.55 OL-KR25 369.9-370.9 OL-KR27 547.38-549.59 OL-KR28 445.4-445.7 Zone of OL-KR1 175-188.5 OL-KR29 302-357 influence OL-KR2 206-275 OL-KR38 372-393 intersections OL-KR10 318-333 OL-KR39 167,5-192,5 OL-KR12 254-275 OL-KR4 353-390 OL-KR13 OL-KR40 624-638 OL-KR14 215-222.5 OL-KR7 260-310 OL-KR15 Part of BFZ098’s influence zone OL-KR8 533-570 OL-KR22 409-435 OL-KR9 468-503,5 OL-KR24 377,5-401,5 OL-KR42 No data yet OL-KR25 363-386,5 OL-KR27 537-550 OL-KR28 445.4-445.7 Applied data Mise-á-la-masse Earthing KR4 368 Connection KR24 395 to KR7 285
KR25 383 KR28 440
KR29 335 KR4 355 3D-seismics Juhlin & Cosma (2007) 408 APPENDIX VII
Gefinex
Strong indications Paananen et al. 2006 Confidence High (3) Class of the Site-scale deformation zone zone Comparison to Updated version of OL-BFZ080 presented in the Geological Site model v.0 geological Site (Paulamäki et al. 2006) model v. 0 Updates - Updated, version 1.0 version history Compilation 25.11.2007 date and Markku Paananen & Liisa Wikström compiled by 409 APPENDIX VII
ID OL-BFZ098
Dimensions 1230 m in NE-SW direction 1100 m in NW-SE direction Description Gently dipping thrust fault with an approximate dip of c. 25 degrees towards SE. It is located only some tens of meters above another site-scale subparallel fault zone OL- BFZ080. The core of the fault is 0.1 – 2.7 m thick, with a typical thickness of 1 m. Geologically OL-BFZ098 is not as distinct as OL-BFZ099 or OL-BFZ002. The fault is intersected by 23 drillholes, and in 12 drillholes a previously determined geological intersection (BFI or BJI) was associated with the zone. According to the RG-classification system, the core consists of densely fractured sections (RiIII) and clay-filled sections (RiIV) in most of the intersecting drillholes. Also, hydraulic conductivity is frequently elevated at the main core. Based on Sampo Gefinex results, fault pair OL-BFZ098 and OL-BFZ089 may extend farther in the NW, at least to KR3. This continuation is now indicated as a separate fault OL-BFZ040.
In some drillholes, the fault core is characterized by pervasive or fracture-controlled illitisation, kaolinisation and sulphidisation or weathering. Geophysically, the zone is observed in several drillholes as a P-wave minimum and an electric conductor. Its geometry is strongy based on Mise-a-la-masse results, seismic reflectors revealed by VSP, 3D and 2D reflection surveys and Sampo Gefinex conductors.
The width of the influence zone of OL-BFZ098 is in average 39.6 m, varying from 15 m (KR22) to 72.5 m (KR7). It is usually characterized by increased fracturing, slickenside fractures, elevated hydraulic conductivity, alteration and geophysical anomalies.
There are no tunnel observations of this fault yet. According to the modelled geometry, the main core would intersect the ONKALO tunnel at chainage c. 3138 – 3141 m.
The BFZ098 seems to form an upper part of the double-sided fault system together with the zone BFZ080. The lower limit for the influence zone of BFZ098 seems to be difficult to separate, especially in the central and western part of the well-investigated area from the upper influence zone of BFZ080. Accordingly, the influence zone in the eastern part of the well-investigated area seems to be clearly thinner.
This modelled zone has the most drill hole intersections, total 23, but only 22 of them has been considered in the description of the influence zone because the newest drill hole intersection KR42 has not yet been logged similarly with older ones to be included here. The width of the influence zone of BFZ098 is in average 31.4 m but varies maximum being 76 m (KR16) and minimum being 7 m (KR8). The width of the main core is in average 0.9 m but varies between in maximum 2 m (KR12) and in minimum 0.1 m (KR10). The average width (the intersection length at the drill hole) of the upper influence zone is 19.9 m and the lower influence zone is 10.8 m. In general the upper influence zone is somewhat wider than the lower one.
The modelled zone seems to be located mainly at the diatexitic or veined gneiss, but in some places the contact between gneiss and larger pegmatitic granite bodies seems to be close by.
The main defining characteristic for the influence zones in many intersections is a 410 APPENDIX VII continuous hydrological conductivity both at the core section and in the influence zone. In few drill holes, for instance KR14 and KR27, the influence zone has increased hydraulic conductivity caused by single conductive fractures, often also alteration at the same place, without any signs of larger core sections in vicinity. However, usually the highest conductivity is measured at or close to the core sections. Few exceptional drill holes are KR9 with hydraulic conductivity only at the main core and KR12 with very limited hydraulic conductivity at the core or very close by. A special feature at KR4 is clearly increasing TDS at the modelled drill hole intersection while it disappears in the main core section of the following modelled zone BFZ080.
The geophysical anomalies, the acoustic long normal and short normal minimum, are very important tools to define this influence zone. In most cases they seem to describe the influence zone together with the hydraulic conductivity while the fracturing has decreased and no other significant features are identifiable. In addition the geophysical anomalies often continue further down and covers also another zone ending at the end of the lower influence zone for BFZ080. In those cases the lower limit for the influence zone has been artificially cut.
Alteration is also a characteristic feature describing this zone. It appears either as pervasive kaolinisation or illitisation around the core or abundant kaolinisation, sulphidisation and illitisation in fractures. A section with pervasive sulphidisation is also met in KR40. Alteration is not seen in the intersections of KR4, KR10, KR14, KR24, KR27 and KR29, i.e. in the ONKALO area, but is abundant east and north of the ONKALO area.
Increase in fracturing has not been as clear phenomenon in this zone as it is in BFZ002 and BFZ099. However, a clear increase in fracturing may describe the zone in certain drill holes, but it cannot be taken as a defining factor because it is not always distinctive for this zone. In some drill holes fracturing increases only slightly compared to averagely fractured rock mass. In addition, often the more fractured part of the intersection is concentrated very closely around the core, but still the alteration or hydraulically conductive fractures continue further and the influence zone limit is defined based on them. Also amount of shear fractures, i.e. the slickensided fractures, is not increased as characteristically as it is for the BFZ099 and BFZ002. The slickensided fractures exist and in most cases are concentrated close to the core sections, though single ones can be found in the whole influence zone. In some drill holes, like KR27, there are few slickensided fractures indicating the core section, but no mapped core or Ri-section.
As mentioned earlier in the case of KR14 and KR27 drill hole intersections are without any clear core section. The main type of intersections based on Ri- classification is RiIII. In addition, RiIV-class intersection can be found in KR7, KR8, KR25, KR28, KR38, KR39 and KR40. For this modelled zone there is no drill hole intersection, which would belong to class RiV. It is interpreted that this zone has not gone through as much movement neither has been exposed to as much strain as BFZ099 and BFZ002.
Generally, the geological logging has described the zone to be either brittle fault zone intersection or brittle joint zone intersection, but in three drill hole intersections, in KR7, KR10 and KR12, located in the central part of the well-investigated area, a 411 APPENDIX VII
high-grade ductile deformation zone intersection has also been mapped in addition to brittle fault zone.
The defined intersection in KR1, KR2 and KR39 are very close to the surface and for this reason the upper limit for the influence zone seems to be difficult to define and may seem to be quite artificial, especially in the case of KR39.
Geometry of the Gently dipping semiplanar feature, dip direction/dip c. 150/25. zone
Core OL-KR1 142-143 OL-KR39 147.0-148.0 intersections OL-KR10 271.5-271.6 OL-KR4 313.4-314.0 OL-KR14 183-184 OL-KR40 611.8 - 611.9 OL-KR2 106.7 - 107.2 OL-KR7 227.1-228.5 OL-KR22 390.8-391.5 OL-KR8 452.7-453.1 OL-KR23 427.6-428.5 OL-KR9 444.2-445.1 OL-KR24 330-331.5 OL-KR42 197.7-198.8 OL-KR25 350.5-350.8 OL-KR12 144 - 146 OL-KR27 516.8 - 517.8 OL-KR15 148.2 - 148.8 OL-KR28 388-389.8 OL-KR16 127.5 - 130.2 OL-KR29 251.5-251.8 OL-KR17 128.9 - 129.5 OL-KR38 307.4-308.3 Zone of OL-KR1 100 – 167 OL-KR39 114 – 160 influence OL-KR10 238 – 275,5 OL-KR4 298-352 intersections OL-KR14 178,5-187,5 OL-KR40 598 – 616.5 OL-KR2 94 -117 OL-KR7 191 – 257.5 OL-KR22 382.5 – 397.5 OL-KR8 448 – 455 OL-KR23 420 – 431 OL-KR9 437-450 OL-KR24 294-332.5 OL-KR42 Not determined OL-KR25 340-355 OL-KR12 125– 170 OL-KR27 505 – 522.5 OL-KR15 117,5-150 OL-KR28 379 - 395 OL-KR16 82,5 – 158,5 OL-KR29 240,5-261 OL-KR 17 106-144,5 OL-KR38 305 – 356.5 Applied data Mise-á-la-masse Earthing KR4 314 Connection KR1 160 to KR14 215 KR2 75-125 KR28 390
KR28 442 KR23 435
KR29 335 KR7 220 3D-seismics
Strong reflections Juhlin & Cosma 2007 Gefinex
Strong indications Paananen et al. 2006 412 APPENDIX VII
Confidence High (3) Class of the Site-scale deformation zone zone Comparison to Updated version of OL-BFZ098 presented in the Geological Site model v.0 geological Site (Paulamäki et al. 2006) model v. 0 Updates - Updated, version 1.0 version history Compilation 22.11.2007 date and Markku Paananen & Liisa Wikström compiled by Local-scale brittle deformation zones
ID Size Geology Confidence Drillhole Core intersections Orientation (dip Geophysics (m) direction/dip°)
OL-BFZ003 c. 680 x 300 m KR5: Densely-fractured intersection in the veined gneis (VGN). Part of Medium KR5 405.8-409.5 164/25 KR5: resistivity the fractures are parallel to foliation and part of them are cross-cutting KR19 412.4-413.1 minimumimum foliation and the core in low angle. There is an older small-scale KR19: P-wave breakage, which is welded. The intersection of these two fracture minimumimum orientations has obviously gathered fluids, because it seems to be VSP III KR5 429 m: remarkably altered compared to its surroundings, for example, strong 229/50° pervasive kaolinization can be noticed. VSP I KR19 398 m: KR19: The intersection contains old, welded fractures with calcite 175/39° infillings. The intersection contains 14 joints.The fractures dip VSP I KR19 430 m: directions are towards SE with moderate dip. The rock in the 115/56° intersection is more fractured at 412.36-413.11 m (10 fractures). The VSP III KR19 412 m: majority of the fractures (8) in the intersection exhibit a slickenside 252/74° surface, with the striation direction towards E with almost horizontal plunge. At 413.11-413.20 m and 414.62 m the fractures show water conductivity (kaoline infilling). 413 OL-BFZ005 666 x 240 m Old welded, calcite bearing fractures, which have been reactivated later. Medium KR13 KR14 322-324 164/34 P-wave minimumimum Slickesides and occasionally clay infilling and signs of high hydraulic KR15 KR19 446.4-448.1 VSP KR19 159 m: 155/10° conductivity. KR21 449.9-451.9 VSP KR14 439 m: 160/38° 155.3-155.8 VSP KR13 320 m: 149/65° 277.0-278.0 and 144/56°
OL-BFZ006 500 x 412 m The fault is composed of old, welded, calcite and mica bearing Low KR19 114.3-114.8 235/45 P-wave minimum, fractuResistivity The feldspars are altered (sericitized). Most of the KR32 175.25 - 176.78 susceptibility maximum fractures show signs of water conductivity (kaoline infillings). and resistivity minimum in Occasionally gouges (small rock particles in gray clay matrix). The rock KR19 is mainly composed by slightly altered VGN. In KR19 the fractures are randomly orientated, but in KR32 they are mainly dipping to south.
OL-BFZ007 300 x 193 m The fault is mainly composed of old, welded, calcite bearing fractures, Low KR19B 19.3-20.7 108/33 some of which have been reactivated later. The fractures are randomly
orientated. Two slickenside surfaces, one (at 23.15 m) with the striation APPENDIX VIII direction towards SE with almost horizontal plunge and another slickenside-surface (at 23.17 m), which is shattered. The rock in the intersection is evenly fractured (app. 8 fractures/m). Most of the fractures show signs of water conductivity (kaoline infillings). OL-BFZ008 400 X 295 m Densely fractured zone. In KR2, the fractures are parallel and Medium KR2 45.56-46.68 157/10 Resistivity minimum in concordant with foliation, in KR13 there are two fracture sets, one KR13 36.5-38.7 KR2 horizontal and one vertical with a N-S trend and in KR32 the fracture KR32 39.8-42.25 P-wave minimum, caliper orientations are scattered. Old and welded fractures where calcite are maximum and density present. In KR2, pyrite coatings and illite are visible on fracture minimum in KR13 surfaces. In KR32 also kaolinite and clay infillings. Signs of Weak P-wave minimum in reactivation and hydraulic conductivity. KR32
OL-BFZ009 425 x 394 m KR13: Most fractures have dip direction towards SSW with quite a Medium KR13 223.2-225.02 171/27 Resistivity minimum in moderate dip. The fractures with slickenside surfaces show movements KR19 Single fault at 89.58 KR21 of E-W trend with moderate dip. The intersection contains 6-10 KR21 205.1-207.0 VSP II KR13 220 m: fractures/m. There are no signs of water conductivity in fractures. 164/75° KR21: VGN is moderately kaolinitized, epidotized and sericitized at VSP II KR13 224 m: places, at 216-218 m a section of coarse grained pegmatitic granite 260/79° (PGR) occurs. The fractures are quite randomly orientated but one set parallel to the foliation can be distinguished (dip/dipdirection 21/180). Slickensides with striations in a N-S direction usually plunging about 40 degrees towards north. The movement has often been sinistral. The joints often have infillings of kaolinite and calcite. Some fractures show signs of water conductivity and have thick greyish clay infillings.
OL-BFZ010 400 x 395 m PGR containing voluminous mica-rich parts, around which the rock has Low KR3 159.0-161.2 190/50 P-wave and resistivity
slipped and plenty of slickensides were born. Slight alteration, some minimum, caliper and 414 pyrite on fracture surfaces and sporadic illite-coatings. magnetic maximum VSP I KR3 165 m: 174/15°
OL-BFZ011 500 x 500 m VGN and a cross-cutting narrow pegmatite. Fractured, slickensides, Low KR9 149.0 - 149.3 095/15 P-wave and resistivity sulphide-fillings and porosity. Fractures are quite parallel. No open KR40 203.55 - 204 minimum fracturesistivity VSP II KR9 140 m: 170/39° OL-BFZ012 500 x 350 m Mostly VGN and short sections of PGR and grey-red, fine- to medium- Low KR27 93.1 - 95.7 128/53 P-wave and resistivity grained, sheared rock that resembles VGN. VGN is greenish in colour minimum due to propable illite alteration. PGR exhibits a red oxidation (paleo). Caliper and magnetic Strong alteration and paleo-shearing, which propably has been maximum. reactivated later. The rock is partly porous, because of the mineral leaching. Gouges with unidentified clay minerals. Some slickenside surfaces but no directions can be observed. Indications of water flow.
The fractures mostly follow the foliation in VGN, but the grey-red, fine- APPENDIX VIII to medium-grained rock exhibit several fracture directions. Randomly oriented fractures, welded by calcite. OL-BFZ013 122 x 714 m K-feldspar porphyric tonalitic-granodioritic-granitic gneiss (TTG). The Medium KR27 128.23 80/69 Resistivity minimum, K-feldpar porphyrs are 0.5-3 cm. Water conducting fractures containing KR40 129.6 magnetic maximum greenish "silt-sand". No alteration observed. Old, randomly oriented fractures, welded by calcite. The fractures are randomly orientated.
OL-BFZ015 590 x 571 m Chlorite-, calcite- and illite-coated fracturesistivity In places the Low KR8 304.8-306 091/64 P-wave and resistivity feldspars of granitic veins in mica gneiss are greenish due to strong minimum, illitisation. The core of the zone is mostly composed of a quartz vein. Caliper max. Cavities, which are filled by some mineral (quartz?). Many steeply MAM KR8 310 -> dipping slickensides. A single water-conductive fracture. KR28 245 & 368 m VSP III KR8 294 m: 160/19° OL-BFZ016 500 x 500 m The fault is within the diatexitic gneiss (DGN), with some short sections Low KR8 379.2-379.8 355/34 P-wave and resistivity of mafic gneiss (MFGN). Old and welded fractures where calcite is minimum, present. These old fractures have partly been reactivated later. The Magnetic maximum intersection contains 50 joints. The rock is most fractured in section MAM KR8 380 m -> 379.18-379.80, containing 18 fracturesistivity Dip directions of the KR27 431 m fractures are towards the NNW, with moderate to steep dip. Numerous VSP II KR8 368 m: slickenside surfaces with a NE-SW striation trend. The movement on 345/63° surfaces is random.
OL-BFZ017 332 x 312 m The fault lies inside the brittle joint intersection BJI_OL_KR23_04410- Low KR23 48.0-51.0 230/09 P-wave and resistivity
05580. Fracture density is approximately 10 fractures per meter. The minimum, 415 rock contains large amounts of old and healed fractures (paleofractures) Caliper maximum, with calcite or mica infillings. Some "younger" joints are probably old occasionally magnetic joints that have been reopened either naturally or mechanicaly during maximum the drillings. The joints usually have chlorite or clay infillings. Signs of water conductivity.
OL-BFZ020 400 x 400 m The fault lies within the VGN and PGR. PGR sections have old welded Low KR25 576.2-576.9 194/33 P-wave and resistivity calcite-bearing fracturesistivity Several slickenside surfaces, but the minimum orientation of the striation varies. Some of the fractures are water Caliper and magnetic conducting. These fractures contain kaolinite and grayish clay infillings. maximum
OL-BFZ022 150 x 150 m The fault is within the MFGN. Several slickensides. RiIII-zone and Low KR29 324.0-325.0 050/21 P-wave and resistivity elevated hydarulic conductivity. minimum MAM KR29 335 -> KR8 APPENDIX VIII 495, KR24 358, KR28 446, KR4 360, KR7 240 m Conductor OL-MAM-018 OL-BFZ024 500 x 500 m The fault is within the DGN, with a short section of PGR. Some of the Low KR29 557.0 - 558.3 139/47 P-wave and resistivity feldspars are altered to illite. A few old and welded fractures with minimum calcite infillings. Some of the fractures contain kaolinite and illite Caliper maximum infillings. These fractures show signs of water conductivity and some of MAM KR29 553 m -> them also exhibit green-grey clay infillings. There is, however, no KR4 490 m indication of water flow in the flow measurements. The main dip direction is towards E with a moderate dip.
OL-BFZ025 450 x 310 m KR15: The plagioclases of the VGN are slightly altered to Medium KR15 327.1-330.1 183/37 P-wave and resistivity sericite/epidote. The intersection contains a quartz vein with sphalerite KR2 219.5-222.1 minimum and chalcopyrite. It also contains a few old and welded fractures with Magnetic maximum calcite infillings. The fractures dip direction and dip is scattered, with a VSP II KR2 205 m: concentration of fractures showing a dip direction towards SSW with a 213/64° moderate dip. The fractures are partly parallel to the foliation. Occasional gouge (dark grey clay infilling), no water conductivity data. Several slickenside surfaces, having a striation direction from E to S, with a moderate plunge. KR2: Sheared mica-prevailing rock and cross-cutting pegmatite are broken. Old thin fractures healed by calcite are cross-cutting core in low angle and are almost perpendicular to foliation. Younger fractures follow the foliation. Strong illitisation, also kaolinite can be seen as powderised spots on fracture surfaces.
OL-BFZ028 300 x 300 m The fault is mainly composed of clearly foliated TGG and one section Medium KR13 368-369 269/82 P-wave and resistivity 416 of quartz. The fault is relatively unfractured but contains signs of paleo- minimum shearing with old welded fractures with greyish matrix and calcite Caliper maximum infillings. The fractures have a random direction with steep dip. Several VSP II KR13 379 m: slickenside surfaces which are randomly orientated (moderate dip). 270/83° Occasional signs of water conductivity.
OL-BFZ030 c. 850 x 360- KR33: The intersection IS composed of VGN and DGN containing 55 Medium KR33 278.6-280.6 c. 100/45 P-wave minimum, 400 m fractures, some of which are slickensides. Fracture density is varying KR39 450.4-450.8 magnetic maximum inside the intersection and also technical breaking occurs in two 10-15 KR2 Single fault at 199.33 Caliper maximum cm sections. Core loss in two depths (15 cm and 20 cm). Carbonate, VSP II KR2 205 m: kaolinite and illite infillings. Faults in two different direction. Clear 213/66° pressure shadow carbonates in one fault in drillhole direction. Some old MAM KR33 270-275 -> welded fracturesistivity Not clear main directions of fracturing. High KR4 760 content of blueish pinitized cordierite with grain size of 1-10 mm. In appearances of K-feldspar grains also indicators of ductile shear. APPENDIX VIII
OL-BFZ031 500 x 495 m The rock is composed of MGN. In the fault, a couple of slickenside Low KR33 286.8 - 288.1 109/66 P-wave minimum fractures with strong striation. Fractures in different directions but usually dipping to ESE following the foliation (66/121°). A lineation on slickenside surface 30/180°. Slight kaolinite alteration. OL-BFZ034 405 x 116 m The rock is mostly composed of DGN, with some small sections of Low KR25 165.8 - 166.0 62/10 Resistivity minimum, VGN and quartz gneiss (QGN). The rock is irregular and no clear KR28 Single fault at 179.13 Magnetic maximum foliation can be observed. The fractures are randomly orientated with a Density & caliper nearly horizontal dip. Several fractures with slickenside surfaces. The maximum lineation on the slickenside surface has a trend varying from NW to NE, Conductor OL-GEOF-001: with variable plunge. The slickenside surfaces mostly show a KR25 118.4 – 125 m, KR4 movement: dextral from above, sinistral from the east and sinistral from 134 – 141 m, KR28 177.7 the south. A few old and welded fractures with calcite are present. – 179.9 m, KR22 189.4 – Occasional signs of water conductivity. 194.4 m, KR23 197.8 – 201 m, KR37 226.1 – 227.5 m, KR38 133.3 m – 137.3 m and KR24 131.6 – 135.2 m and possibly 292.4 – 293.1 m and 304.8 – 305.9 m in drillhole KR27
OL-BFZ035 100 x 92 m Highly fractured fault within the DGN, also a few old, welded, calcite- Low KR31 41.0-43.1 166/84 Several caliper anomalies and pyrite-bearing fractures occur. The fractures are randomly orientated with moderate dip. The core of the fault is strongly crushed. According to the water conducting measurements, these grey clay- bearing fractures of the fault core have acted as a water channel. 417 OL-BFZ036 650 x 150 m The rock is mainly composed of VGN and some sections of massive Low KR14 473.1-473.6 (3 group B 118/40 Weak P-wave and PGR. Densely fractured fault zone, the fractures showing a dip direction faults) resistivity minimum towards ENE with a moderate dip. Several fractures with a slickenside VSP I KR14 440 m: surface, which have a striation direction towards NE with a moderate 160/36 plunge. Three of these slickenside surfaces indicate a movement: VSP II KR14 510 m: sinistral from above, dextral from the east and dextral from the south. 160/74 No signs of water conductivity.
OL-BFZ039 c. 1040 x 360 m The intersection in KR29 is composed of VGN and DGN, with some Low KR29 543.8 - 546.4 133-140/40 P-wave minimum in KR7 short sections of PGR. The feldspars are often altered to illite. The KR7 Single fault at 473.92 Weak resistivity minimum intersection contains a few old and welded fractures with calcite and and magnetic maximum in pyrite infillings, especially in the PGR. Several of the fractures contain KR29 kaolinite and illite infillings. Accordingly, a majority of the fractures MAM KR29 557 m -> show signs of water conductivity and some of them also have green- KR4 490 m and KR7 410 grey clay infillings. There is, however, no indication of water flow in m the flow measurements. The intersection exhibits 61 fractures, with a Conductor OL-MAM005 APPENDIX VIII dip direction towards SE with a moderate dip. The rock is more fractured in section 543.80-547.12 m (37 joints). The intersection exhibit 29 fractures with a slickenside surface, which have a striation direction varying from SE to SW, with a moderate plunge. OL-BFZ041 700 x 700 m Clay- and grain-filled fractures, slickensides and weathering as well as High KR6 KR13 10.9-11.8 156/31 P-wave & resistivity porosity. Some fracture coatings are rusty. Within the VGN there is a KR19B KR32 167.9-170.0 minimum in places strong shearing in narrow zones. Moderate to strong fracture-controlled KR41 KR42 44.6-46.2 MAM KR13 150-290 m -> kaolinisation and pervasive illitisation. A few old, "welded" fractures 175-177 KR25 518 m with calcite infilling occur, which have reactivated later. In KR19B at 213.4-214.5 40.69-41.35 m, 42.97-43.41 m and 44.80-44.85 m, the fractures show 314.1-315.6 water conductivity (kaolinite infilling). RiIV zones in KR41 and KR42.
OL-BFZ043 250 x 335 A set of parallel quite steeply-dipping (78/115°) slickensides in KR10, High KR10 271.5-271.6 087/83 Microearthquake has which cross-cut the foliation. Slight pyrite coatings on fracture surfaces. ONKALO 1363.31-1364.11 occurred in the fracture of the ONKALO tunnel. The intersection in ONKALO is composed of one main fault (87/100°), which crosscuts the whole tunnel. This fault contains a ca. 15 cm wide section of epidote altered rock around the fracture in the left wall. As fracture filling it contains calcite, quartz, epidote and unidentified clays with a maximum thickness of 30 mm. Striation striation could not be determined from the slickenside surface, but the fracture has faulted to MGN inclusions dextrally when viewed from south to north in the left wall. In addition to the main fault the intersection contains several conjugate fractures either combining with the main fault or in the near vicinity of it. These fractures mainly have an undulating smooth profile and mainly contain calcite and epidote as fracture filling. This gives an indication of some kind of a hydrothermal alteration within this zone. The intersection contains a ca. 1.40 m wide “damage zone” with 418 approximately equal extent on both sides of the main fault.
OL-BFZ044 420 x 155 The fault zone is composed of VGN, which contains a few old, welded, Medium KR19 99.5-101.9 146/37 P-wave and resistivity calcite-bearing fractures, which have been reactivated later. Some of minimum the slickenside fractures seem to be created into paleo-fractures, which MAM KR19 105-135 -> may have been reactivated. In section of 102.28-102.52 m there are KR25 383 & 518 water conductive fractures (three fractures). Pervasive illitisation occur.
OL-BFZ045 535 x 290 The fault zone is mainly composed of strongly foliated (sheared) VGN, Medium KR13 409.8-410.5 101/67 Clear P-wave and which is intensely fractured (16 fractures/m) at 409.79-410.50 m and 10 resistivity minimum cm core loss has occurred. At this place the rock is water conductive. Density minimum
Caliper maximum APPENDIX VIII VSP II KR13 410 m: 130/63
OL-BFZ046 750 x 200 The fault zone is composed of MGN, which exhibits a few old, welded, Low KR15 495.5-496.4 135/76 No clear indications calcite-bearing fracturesistivity The fractures (13) dip towards the SE with horizontal to steep dip, being parallel to the foliation. The majority of the fractures in the intersection contains slickenside surfaces (9) with a NE-SW trend. OL-BFZ048 776 x 400 A slightly sheared and deformed (semi-brittle) fault zone within the Medium KR8 KR27 348.6-349.2 155/42 P-wave & resistivity DGN containing old and welded fractures, which have partly been KR40 292.8-294.1 minimumimum reactivated later. The slickenside surfaces are usually planar and parallel 401.34-402.1 KR27: mag max. to the foliation. The slickensides have a lineation with a NE-SW trend MAM KR27 250-305 -> and often contain some carbonate, pyrite and clay minerals. Many KR25 122 fractures show signs of water conductivity. MAM KR27 296 m -> KR8 245 VSP II KR8 360 m: 345/62
OL-BFZ049 410 x 200 Densely-fractured intersection in VGN. Random fracturing with Low KR6 506.9-508.8 091/18 (P-wave minimum, mag fractures parallel to and crosscutting the foliation. An older small-scale max.) microfracturing and -breakage, which is welded. On slickensides, VSP I KR6 500 m: 255/70 graphite-coatings can be seen. Drilling-induced splitting of the core sample.
OL-BFZ050 560 x 110 DGN and VGN are the main rock types in the zone. The feldspars are Medium KR16 127.5-130.2 112/50 KR16: resistivity slightly altered to sericite. The fault zone contains a few old and KR17 KR32 128.3-129.8 minimum, mag. max. welded fractures with calcite infillings. The average fracture frequency 86.8-88.0 KR17: P-wave, res & isf 3.5 fractures/m.The water conductivity measurements show signs of density minimumimum, water flowing at several places in KR16 and KR17, showing kaolinite mag & caliper max. and gray-green clay infillings. KR32: P-wave & resistivity minimumimum
OL-BFZ053 c. 1080 x 495 m The intersection in KR27 contains roughly 1 slickenside surface per Medium KR27 304 - 306 120/60 - 130/80 Resistivity minimum,
meter and has not a particularly high fracture density. The section and KR40 789.58 - 796.69 magnetic maximum 419 its surrounding rocks contain some healed fractures with calcite KR27 296 m ->ground infillings. Some old and healed fractures may have been reactivated. surface and KR8 245 m The slickenside surfaces often occur parallel to the foliation (NW-SE) and normaly have lineations with a NE-SW trend. The slickensides often contain some carbonates. The rocktype is mainly DGN but in the center of this intersection there is a section of PGR. The rock is cohesive but some small parts show signs of semi-brittle deformation with angular feldspar crystals (5 mm). RiIV zone in KR40.
OL-BFZ055 c. 1030 x 640 m The intersection in KR27 contains coarse-grained, deformed PGR and Medium KR23 175.97 - 176.83 138/78 KR23: P-wave and lies inside the semi-brittle intersection SFI_OL_KR27_42600-43990 . KR27 429 - 431.5 resistivity minimum The section contains 55 joints, of which 12 have slickenside surfaces. KR40 919.36 - 920.79 KR27: resistivity minimum Most fractures have a NE-SW strike, the slickensides have lineations MAM KR27 431 m -> showing movement in a N-S direction. The fractures usualy have KR4 265 m, KR8 380 m, infillings of calcite and pyrite. The section has a underlying older brittle KR9 385 m, KR40 575 - APPENDIX VIII deformation that may have been reactivated during the formation of this 580 m, KR41 165 m?, intersection. Some technical reopening of the old and healed fractures KR42 220 m? may have occured during the drillings. Core loss at 175.97-176.83 m in KR23. RiIV zone in KR40. OL-BFZ058 c. 530 x 490 m KR22: The intersection is composed of DGN and a couple of short Medium KR22 83.7 - 84.1 119/47 KR22 and KR27: P-wave sections of MGN and VGN. The intersection contains 179 fractures and KR27 338.2 - 339.8 & resistivity minimum, has an average density of 7 fractures/m. Of these fractures at least 16 KR31 103.9 - 104.8 magnetic maximum are slickensides. There is only one set of joints with dip/dip directions MAM KR27 338 m -> of about 20/115° (often parallel to the foliation.). The slickensides have KR8 315 m, KR9 300 - lineations indicating horizontal movement in a NE-SE direction. Some 310 m, KR40 550 m, old and healed fractures with calcite infillings occur. Signs of water KR41 90 m?, KR42 205 - conductivity are observed in some fractures throughout this intersection. 230 m?, ground surface KR27: This brittle fault intersection contains DGN and lies inside the semi-brittle fault intesection BFI_OL_KR27_33385-34842. Fractures and slickensides usually have a NE-SW direction but lineations occure in random directions. The fracures often have some greyish clay infilling, some contain carbonates or grafite. Some of the fractures (with clay infillings) are water conductive. KR31: The intersection is composed of DGN with short section of QGN.
The QGN is slightly altered. The intersection contains a lot of old and welded fractures where calcite and pyrite are present. These old fractures have partly been reactivated later. The fractures show an NE-SW strike, with varying dip. The fractures seem to follow the foliation. The intersection contains 39 joints, with an average of 7 fractures/m. The rock is fractured throughout the intersection. Many of these fractures exhibit signs of water conductivity . 420
OL-BFZ059 c. 300 x 190 m The fault zone contains 61 joints and has an average density of 8 Low KR22 139.9-140.8 145/55 P-wave & resistivity fractures/m. The dominating jointset has a dip/dip directions of about minimum 30/130° but some other directions do occur. At least 8 fractures have Magnetic maximum slickenside surfaces. The slickensides have lineations in variying MAM KR22 150 m -> directions but most have a moderate plunge and are NE-SW trending. KR4 80 m Some old and healed fractures with pyrite infillings are present. Many fractures have graphite infillings. No signs of water conductivity were observed. APPENDIX VIII OL-BFZ060 c. 360 x 330 m KR22: The intersection contains DGN with a slightly banded texture. Medium KR22 194.4 - 195.5 127/32 KR22: P-wave & The intersection contains 79 fractures and has an average joint density KR28 172.6 - 173.2 resistivity minimum, of 6-7 joints/m. At least 10 of these fractures have slickenside surfaces. magnetic maximum Some old and healed joints with calcite infillings occur in the beginning KR28: P-wave minimum, of this intersection. The direction of the joints is a bit variating but one caliper maximum clear jointset parallel to the foliation is distinguished (20/150 °). The MAM KR28 179 m -> slickensides have nearly horizontal striations and most are NE-SW KR22 190 m, KR23 225 trending. Most fractures have calcite and pyrite infillings. No signs of m, KR4 135 m, KR24 134 water conductivity were observed. Some mechanical fracturing of the m old and healed fractures may have occured during the drillings. KR28: Mainly VGN with short sections of PGR and MGN. In VGN (from 170.21 to 173.50 m) there are about 7 fractures/ 1 metre. Two slickenside surfaces are also observed. They seem to be created into paleo-fractures, which may have been reactivated.There are red feldspar crystals (rounded) in VGN. Old welded fractures with biotite, pyrite and calcite infillings are observed. In some places, feldspars are sericitised. At 172.65-172.70 m crushed drillcore. At 173.50- 174.00 MGN contains some old welded calcite-bearing fractures. At 174.00-174.12 m several fractures in random directions. In depth of 174.12-174.90 VGN contains some NE striking slickensides. At 174.90-175.85 m PGR contains some fractures in random orientation and old welded calcite bearing fractures. At 175.85-178.00 m VGN contains only a few fractures in random orientation. In sections of 168.50-171.99 m and 172.90-173.16 m there 421 are water conductive fractures.
OL-BFZ063 475 x 250 m The intersection in KR14 at 446.40-446.83 m is intensely fractured and Medium KR14 KR2 446.4-446.9 266/66 KR14 P-wave & resistivity partly crushed and contains ca. N-S striking, steeply dipping 396.1-396.9 minimum fracturesistivity In KR2 there is a cluster of N-S striking, steeply KR2 resistivity dipping fractures at 396.1-396.9 m. minimumimum VSP I KR14 445 m: 160/38 VSP II KR2 390 m: 145/42
OL-BFZ064 645 x 200 m The zone shows partial shearing, old microfracturing and -breccia, Medium KR1 641.0-642.2 158/40 P-wave minimum which are welded in places by strong silicification. Illitisation occurs KR2 603.6-604.6 both in VGN and PGR. The old welded fracture system is quite vertical and in places opened by drilling. In younger phase there is a faulting in
the direction of the foliation aided by graphite-bearing layers and partly APPENDIX VIII by illite, which can be seen on slickensides. In KR2, the most broken core of the section joins the location of the old microbreccia, graphitic section and illitisation at dept of 603.60 - 604.55 m.No water- conductivity. OL-BFZ065 c. 600 x 600 m KR19: The intersection is composed of VGN with a short section of Low KR19 534.5 - 535.5 098/38 KR19: resistivity PGR. The intersection contains 35 fractures, which dip towards the E KR20 450 - 451.3 minimum, magnetic and the SE with moderate dip. Most of the fractures follow the foliation. maximum Four fractures in the intersection exhibit a slickenside surface, with the KR20: resistivity striation direction towards the NE with moderate plunge. The fractures minimum, magnetic at 533.28-533.32 m, 533.38 m, and 533.91 m show water conductivity maximum (kaoline infilling). At 533.27-533.37 m there is weathered and altered VSP I KR19 539 m: VGN. The intersection also contains old, welded fractures with calcite 217/48° infillings. KR20: The intersection is composed of VGN and contains 6 joints, which are randomly oriented, with a concentration showing a dip direction towards the NE with a moderate dip. The rock is evenly fractured.Four slickenside fractures have SSE trend with almost horizontal to moderate plunge. The intersection contains a few old, calcite bearing, welded fractures. There are no signs of water conductivity.
OL-BFZ066 150 x 150 m A cluster of 6 faults at 46.65-53.76 m in KR4. Low KR4 51.0-52.5 181/49
OL-BFZ067 240 x 295 m A clean-cut fault zone in KR12, in which the fractures are mainly Medium KR12 72.9-73.5 150/45 P-wave minimum in KR12 slickensides with some calcite and sulphides on fracture planes and thin TK4 P17 1.1-2.0 Surface magnetic clayey coatings. Alteration includes at least illite and possible kaolinite. lineament SURFMAGN Slickensides are partly on foliation planes, partly cross-cutting core 0012
sample and foliation in low angle. Some slickensides have graphite- 422 fillings. Drilling has also effect on core splitting. 4 to 5 water- conductive fractures are observed with flow meter. An intensely fractured, strongly weathered, crushed fault zone in TK4 with 20 fractures/90 cm. The fracture pattern in the PGR indicates sinistral sense of faulting along the fault zone.
OL-BFZ068 380 x 145 m The intersection is composed mainly of VGN with a short section of Low KR20 70.6-71.4 158/42 P-wave minimum QGN. In VGN there are old, welded fractures, bearing green unidentified mineral. The intersection contains 21 fractures, which dip towards the SE with moderate dip. At 71.13-71.37 m and 71.79 m there are water conductive fractures. Some mechanical fracturing has occured during the drillings.
OL-BFZ069 460 x 310 m The intersection contains 16 fractures of which 10 have slickenside Low KR13 475.1-475.7 055/50
surfaces. The PGR within the zone does not contain any joints and is APPENDIX VIII also totally undeformed. The slickenside surfaces have lineations in random directions but most plunge towards the south. The F_vector shows a sinistral-dextral-sinistral pattern in most of the faults. No signs of water conductivity occur. OL-BFZ070 420 x 215 m Short section of slickensides occurring in slightly sheared migmatite. Low KR10 505.0-506.0 145/22 P-wave minimum Main part of fractures are slickensides, which are closely parallel to KR12 499.5-499.9 each other and the foliation.
OL-BFZ072 540 x 230 m The intersection in KR13 is composed of VGN with some short sections Low KR13 250.1-250.9 157/42 P-wave minimum of PGR. Both rock types are evenly fractured and contain old and MAM KR13_150-290 m welded fractures where calcite is present. The fractures strike parallel to from KR25_518 m the foliation with a moderate dip towards SSE. VSP KR13 250 m: 180/5°
OL-BFZ074 150 x 150 m Brittle fracturing upon the old sheared, brecciated and welded section. Low KR8 80.0-83.5 043/51 P-wave minimum At a depth of 82.30 m, a high water-conductivity linked to one remarkably large open fracture. Majority of the brittle phase fractures are rather parallel.
OL-BFZ078 570 x 350 m The intersection in KR19 contains old, welded fractures with calcite Low KR13 319-322 104/35 VSP KR13 317.5 m: infillings. Some of these welded fractures have been reactivated later. KR19 182.4-184.8 150/65° The intersection contains 45 joints.The fractures dip towards the NE and KR21 could not be determined VSP KR19 172 m: 220/35° the SE with a moderate dip. The majority of the fractures exhibit a slickenside surface, with the striation direction towards the SE with moderate plunge. At 182.00-183 m and 184.26-184.76 m the fractures show water conductivity (kaoline infilling). In KR13, the intersection contains 14 joints, app. 2-3 fractures/m. The slickenside surfaces are randomly orientated with a moderate dip. The rock (TGG) is strongly foliated. 423
In KR21, the rock in the intersection is composed of strongly banded VGN, which is slightly kaolinitised. The intersection contains 58 joints that usually occur parallel to the foliation. The joints often have infillings of kaolinite and calcite, many healed fractures occure. No kinematic indicators.
OL-BFZ081 430 x 170 4 to 5 single slickensides cross-cutting each other in high angle in Medium KR10 109.7-110.5 122/20 Weak P-wave minimum KR10. Some of the slickensides are parallel to foliation, some of them ONKALO 1159.3-1159.8 (45/121°) cross-cuts foliation. On one slickenside there is a thin pyrite- coating. Fault vector directions are almost parallel and trending to east. Long continuous fault oriented 20/111° in ONKALO in chainage 1155 m with a visible trace length of over 31 m, which splits into two separate fractures towards the end. The fracture follows a zone of KFP that may have been formed under ductile conditions. The KFP zone varies in width from 10-200 cm. The surrounding rocks are VGN with APPENDIX VIII some PGR dykes. The fault cuts through the foliation of the surrounding rocks. At 1184.3 m, the fracture is leaking water from the right side of the tunnel roof (dripping). OL-BFZ082 490 x 160 The intersection is composed of VGN, which contains old, welded, Low KR19 202.3-202.9 170/45 P-wave minimum calcite-bearing fractures. One thick (1 cm), calcite and kaoline-bearing VSP KR19 204.4 m: fracture at 202.50 m (45/170°) has reactivated later, and this has been 168/23° interpreted to be the core of the fault zone. The intersection contains 19 randomly oriented fractures. Most of the fractures show signs of water conductivity (kaoline infillings).
OL-BFZ083 440 x 160 The intersection is composed of VGN, which contains a few old, Low KR19 209.86-211.53 170/45 P-wave minimum welded, calcite-bearing fractures. Some of them have been reactivated later. The intersection consists about 7 fractures/m. Some of the slickenside fractures seem to be created into paleofractures which have been reactivated. At 209.86-209.89 there are two water conductive fractures.
OL-BFZ084 930 x 660 m KR1: Fractures parallell with foliation are abundantly present as well as Medium KR1 108.6-109.9 182/60 P-wave minimum fractures perpendicular to foliation. Macadam-looking core sample, KR3 159.0-161.7 VSP II-III KR1 105-110 however, show some slickensided surfaces. TV-image shows 2 - 3 clear KR7 409.3-410.4 m: 131/62° open fractures. Fracture surfaces carry powder-like clay minerals. KR39 186.4-187.5 VSP KR13 165 m: 175/15° Porosity and seriticisation (zinnwaldite) are detected. Two remarkable TK2 P6 8.5-8.8 water-flow anomalies are situated in this section. KR3: Pegmatite containing voluminous mica-rich parts, around which the rock has slipped and plenty of slickensides were born. Slight alteration, some pyrite on fracture surfaces and sporadic illite-coatings. 424
KR7: A short breakage, which is strongly aided by drilling. Strong geophysical anomalies, except water-conductivity which is insignificant. Older strong ductile shear is visible. TK2: Dextral fault zone upon a high-grade ductile shear zone precursor. The ductile shear zone has been reactivated and the resulting fractures are subsequently healed and welded by calcite and pyrite.
OL-BFZ086 220 x 90 m KR15: The central part of the intersection (148.40-148.60 m) is badly Medium KR15 148.2-148.8 149/34 P-wave minimum crushed and contains a few gouges with unidentified clay mineral (dark KR17 128.9-129.5 gray in colour) and these gouges are also water conductive. KR17: The rock is intensly fractured at 124.30-124.70 m and 128.90- 129.45 m. These sections show signs of water flowing, containing kaolinite and grey-green clay infilling. The latter section also contains APPENDIX VIII 20 cm core loss.
OL-BFZ087 475 x 250 m The intersection contains old, welded fractures with calcite infillings. Low KR19 177.4-178.8 073/24 P-wave minimum Some of these welded fractures have been reactivated later. The majority of the fractures in the intersection exhibit a slickenside surface, with the striation direction towards the SE with moderate plunge. At 182.00-183 m and 184.26-184.76 m the fractures show water conductivity (kaoline infilling). OL-BFZ091 157 x 100 The intersection is mainly composed of PGR, which contains a section Low KR29 849.2-849.5 020/47 MAM KR29_855 m from (849.26-849.53 m) with soft and crushed rock. This section is 27 cm KR4_760 m, weak thick and it is propably water-conductive. The whole intersection has 25 fractures and some of them contain illite and kaolinite infillings, indicating waterflow, although this is not shown in the flow measurements. 10 of these fractures contain a slickenside surface.
OL-BFZ092 510 x 260 m KR13: The intersection is relatively unfractured but contains signs of Medium KR13 363.2-363.7 109/40 KR13: P-wave, resistivity paleoshearing with old welded fractures with greyish matrix and calcite KR19 211.3-212.2 and density minimum, infillings. The intersection contains 51 joints, app. 4 fractures/m. The KR20 179.3-180.0 caliper maximum fractures have a random direction with steep dip. The intersection KR19: P-wave and exhibits 11 slickenside surfaces, which are randomly orientated resistivity minimum (moderate dip). At 363.23-363.70 m the drill core is chrushed and KR20: P-wave and shows signs of water conductivity. resistivity minimum KR19: The intersection contains a few old, welded, calcite bearing fractures. Some of them have been reactivated later. The intersection consists about 7 fractures/m (14 fractures altogether). The fractures are randomly oriented. Four slickenside surfaces are also observed (NE and SE oriented). Some of them seem to be created into paleofractures, which have been reactivated. At 209.86-209.89 m there are two water conductive fractures. KR20: The intersection contains a few old and welded fractures where calcite are present. The whole intersection contains 29 joints.Fractures dip between E and SE with a dip varying from almost horizontal to 425 moderate. The intersection contains one slickenside surface at 181.05 m (SE trend, moderate plunge). Between 179.88 m and 180.26 m there are fractures showing signs of water conductivity.
OL-BFZ094 220 x 100 m Short brittle section in fine-grained mica-rich rock with scarce or no Low KR12 582.4-584.1 117/74 neosome. The rock changes in the bottom of the section into cordierite- bearing gneiss. Brittle section covers an old welded microfracturing and -breccia of some early brittle deformation stage. Fractures and slickensides carry voluminous fillings.
OL-BFZ095 370 x 130 m The intersection is mainly composed of VGN with a short section of Low KR19 75.9-77.0 093/13 PGR. The rock contains old, welded, calcite bearing fractures. Here and there the feldspars are altered (sericitised?). Most of the fractures have APPENDIX VIII dip direction towards the SE with a moderate dip. The rock in the intersection is evenly fractured having an average of 10 fractures/m. The fractures at 76.00-77.00 m show signs of water conductivity (kaoline infillings). At 76.71 m there is 0.07 m core loss. OL-BFZ096 430 x 200 m Mica-rich migmatite displays an old welded microfracturing and - Low KR12 203.2-204.5 244/85 P-wave minimum breccia, which has later broken. Slickensides with fillings of calcite and VSP II KR12 205 m: small fragments cemented by hard clay. 213/65°
OL-BFZ097 100 x 100 A set of faults (13 slickensides) at 51.65-54.52 m dominated by faults Low KR4 51.7-54.5 156/47 dipping moderately to the SE-SSE (group E).
OL-BFZ100 750 x 340 m The fault consists of a clearly definable core and transition zone; the High KR22 338.20-339.6 098/67 MAM from the ground core has a varying width of 0.15 to 2 metres and has in places strongly KR23 372.52-373.04 surfase to ONKALO developed schistose fabric with associated slickensided surfaces. KR25 217.32-217.93 Quartz, pyrite, chalcopyrite, graphite, galena and talc mineralisations KR26 96.73-97.94 can be observed within the fault core. Pyrite mineralisation occurs KR28 181.50-182.95 within cavities associated with quartz-filled tension veins.Chalcopyrite KR34 49.66-50.61 seems to be associated with calcite-filled fractures/tension veins. The KR37 55.57-57.01 fault zone shows sinistral sense of movement by numerous kinematic KR42 191.01-194.36 indicators. PH1 152.72-154.11 PH4 27.01-30.57 ONK 128.5-129.3 ONK 521.5-523.0 ONK 900.2-906.4 (core?) ONK 1592.9-1595.0 (core?) ONK 1819.0-1831.0 (core?) TK7 TK11 426 OL-BFZ101 40 x 70 Brittle fault intersection, which is visible across the whole tunnel and High c. 140/15 GPR indications from has a trace length of more than 40 meters. The fault plane has an OL-PP40 17.95-18.55 TK7, mapping sections average dip/dip direction of 10/151. The width of the zone is OL-PP41 27.10-27.57 P10-P11 approximately 2 meters. The fault has partly a semi-brittle character as OL-PR5 4.20-4.61 the foliation near the fault shows well-developed deflection and thus OL-PR6 5.52- 6.00 indicating that the hanging wall of the fault has moved towards west OL-PR7 10.62-11.10 (reverse fault). The fault plane crosscuts the foliation. Accordingly, OL-PR8 12.70-13.21 sense-of-movement viewed from south is sinistral. The fault has a well OL-PR9 11.27-11.79 developed 10-30 cm wide core, which contains of intensively crushed OL-PH1 98.59-99.76 rock (0.1-30 mm in diameter) and greenish clay. The core can be OL-TK7 P10-P11 defined as fault breccia, as most of the material consists of rock pieces ONKALO 66 - 68 (70-80%).The fault has also an intensively altered "transition intersection" in which the rock is quite homogenous K-feldspar porphyric tonalite/granodiorite; the K-feldspar phenocrysts are 5-50 mm in diameter and are both eu- to subhedral. The width of this K-feldspar porhyritic zone is 0.2-2 m in the hanging wall and approximately 1 meter in the footwall. The zone has gradational contacts to the VGN, APPENDIX VIII which is the main rock type of the fault area. OL-BFZ102 380 x 315 ONKALO 240.0-282.0: Sheared and altered zone, the clearest High ONKALO could not determined 110-170/40-60 Zone of low P-wave alterations are visible in the kaolinisation of feldspar grains and ONKALO could not determined velocity in the seismic P- chloritisation of biotite. Rotation is visible in the feldspar grains. The TK4 could not determined velocity map. Anomalies direction of shearing is 47/125°, which is same as the direction of the in the magnetic ground foliation. The intersection is visible across the whole tunnel. In some survey and the horizontal- parts there is strongly sheared and mylonitized sections. Plenty of pale loop EM data. kaoline veins/grains. ONKALO 449.7-453.8: Sheared and altered zone. The rock is intensively kaolinitised. In the center of this intersection there is a strongly sheared zone, the width of which varies 30-100 mm. This sheared zone is greenish and composed of kl, bt, ka and sv. Some sand fragments are also present. The direction of shearing is 56/158°, which is same as the direction of the foliation. The intersection is visible across the whole tunnel. The surrounding rock is also pervasively kaolinitised and has some rotated grains. One undulating slickensided fracture with an uncertain lineation (24/240°) is also present. TK4, P58- P59: Strongly altered (chlorite, kaolinite, illite) and weathered migmatite has intensely broken along the foliation planes or narrow biotite-rich melanosome schlieren between the granite veins.
OL-BFZ104 645 x 300 m Graphite-rich section ("graphite schist") in mica-rich gneiss. Core Low KR2 1039.4-1040.9 189/43 P-wave minimum sample has totally splitted during the drilling. In number of graphitic VSP KR2 1010 m: 170/37°
pieces slickensides can be detected and some sulphides occur together 427 with graphite .
OL-BFZ105 700 x 280 m Mica-rich, small-grained rock, where graphite-bearing sections are Low KR11 895.5-896.0 189/43 P-wave minimum slickensided. Between graphitic sections there are thin (1 - 2 mm) pyrrhotite stripes and layers. Slickensides are subparallel and concordant with foliation. Under brittle features there is a small section of high-grade ductile shear. TV image shows one open fracture in the very top of the section, however, with no water conductivity. APPENDIX VIII OL-BFZ106 670 x 210 m KR22: Inside the section lies the semi-ductile intersection Medium KR22 46.0-48.0 057/48 P-wave minimum, surface SFI_OL_KR22_04335-06530. The dip direction of the fractures are KR27 93.1-95.7 magnetic lineament mainly towards the E and SE. A few old, "welded" fractures with calcite SURFMAGN 0173, infilling are present. The intersection contains several slickensides seismic lineament between 46.00-48.00 m. Slickensides follow the foliation. The lineation SEISMIC 0048. on the slickenside surfaces often has a NE-SW trend with varying plunge and they contain graphite and chlorite. The beginning of this section is badly crushed (partly mechanical). Signs of water conductivity were observed in sections 50.00-51.20 m and 66.53-67.12 m. The fractures in the former section contains greenish clay (1 mm thick, unidentified) and the latter graphite, kaolinite and some unidentified greenish clay. KR27: The intersection contains mostly VGN with short sections of PGR and a grey-red, fine-medium grained, sheared rock that resembles VGN at 86.31-88.03 m and 92.80-94.25 m. The VGN is greenish in colour, due to propable illite alteration. The PGR exhibits a red oxidation (paleo). The intersection is strongly altered and shows a paleoshearing, which propably later has been reactivated. The rock is partly porous, because of the mineral leaching. The rock exhibits in one joint a black mineral (goethite?) and a few gouges with unidentified clay minerals. The intersection contains some slickenside surfaces but no directions can be observed. Water flowing has been determined in following fractures: 84.60 m, 86.40 m, 88.00 m, 89.80 m, 92.75 m and 95.50 m. The fractures mostly follow the foliation in VGN, but the grey-red, fine- to 428 medium- grained rock exhibit several fracture directions. The intersection also contains old, randomly oriented "welded" fractures; fractures are welded by calcite.
OL-BFZ107 730 x 350 m Plenty of slickensides and a short section of graphite-filled slickensides. Low KR12 745.2-747.2 188/52 P-wave minimumi Core sample is badly splitted. There seems to be an old fracture set and microbreccia cross-cutting the foliation, but that is healed by calcite. A strong ductile shear in narrow zones (10 - 20 cm).
OL-BFZ108 680 x 240 m Short fault in mica-rich gneiss. An old small-scale microfracturing - Medium KR6 366.7-367.0 180/30 P-wave minimum breccia, which is welded. Graphite is detected on younger slickensides parallel to the foliation. In the bottom part, there is a gouge with plenty
of graphite and in situ sheared rock fragments. APPENDIX VIII
OL-BFZ109 845 x 200 m TK2: Several narrow parallel fracture zones concordantly with the Medium KR7 82.7-83.1 157/33 Surface magnetic foliation. The total width of the fracture zone in mapping sections P25- TK2 Could not be lineament SURFMAGN P26 is about 6 m. determined 0166. KR7: Short set of parallel fractures in the VGN. One slickenside and P-wave minimumimum in few open fractures. Slightly porous and altered looking intersection. KR7. OL-BFZ110 540 x 460 m TK13: Rock contains old and welded fractures with thin calcite Medium KR13 279.1-280.4 210/40 P-wave minimum in KR13 infillings. The fractures have a direction parallel to the foliation (E-W KR19 122.75-123.05 and KR19. trend) with moderate dip towards the S. The intersection contains 51 TK8 P71 1.3-2.5 fractures, app. 8 fractures/m. TK19: The rock contains old, welded, calcite-bearing fractures. The feldspars in PGR are altered (sericitised). The intersection contains 26 fractures (ca. 8 fractures/m). At 122.75-123.05 m there are two gouges (small rock particles in dark gray clay matrix). At 122.64-123.05 m and 124.69-124.81 m the fractures show signs of water conductivity (kaoline infillings).
TK8: An intersection with altered and crushed rock, which strikes parallel to the foliation.
OL-BFZ111 49 x 39 m KR24: RiIII 8.08-11.04 m. Medium KR24 KR38 7.44 237/77 ONKALO: long fractures in ONKALO near KR24. ONKALO 23.97 KR38: The brittle joint intersection OL-KR38_BJI 22.75-24.95 contains a few old and healed fractures with calcite fillings. The intersection is intensely fractured at 23.92-24.37 m (contact of MFGN and DGN), with 11 fractures. Some of the fractures contain kaolinite fillings. The fracture fillings indicate that the fractures at 23.97 m and 24.22 m are water conductive and this is supported by the flow measurement data. The fractures are randomly orientated. Some mechanical fracturing has
occured during the drilling. Feldspars in DGN are altered having a 429 yellow-greenish colour.
OL-BFZ112 100 x 100 m The brittle fault zone intersection ONK-BFI-24250-28700 is composed High ONKALO 264-265 009/17 of a single subhorizontal chlorite- and clay-filled fracture. This fracture has a trace length of approximately 50 m and it is visible in both walls. This subhorizontal fracture (17/009°) was observed from chainage 242- 287 m. The thickness of the clay and chlorite filling in the fracture varies from 5 mm to 5 cm; accordingly the Joint alteration numbers (Ja) also varies between 6-8. The clay-filled fracture is surrounded by a 40 cm wide zone of soft and weathered rock in the latter part (chainage 280-285 m) of the intersection. APPENDIX VIII OL-BFZ113 54 x 73 m ONK-BFI-29200-29500: Chainage 292.00–295.00 contains a BFI, High ONKALO 293 - 294 273/42 which comprises several moderately dipping illite-, chlorite- and clay- filled fractures. The thickness of the clay and chlorite filling in the fracture varies from 3 mm to 3 cm; accordingly the Joint alteration numbers (Ja) also varies between 4-8. The rock surrounding the main fracture is altered and weathered; this zone of weathered rock is approximately 65 cm wide. The main fracture has dip/dip direction of 42/273° and it is visible across the tunnel, reaching the roof at chainage 305 m. The latter part of the intersection shows several similar illite-, chlorite- and clay-filled fractures and some of them also contain graphite. However, the collection of detailed mapping data was inhibited by the poor rock quality in this section.
OL-BFZ114 141 x 112 m The brittle fault zone intersection ONK-BFI-30950-31100 is composed Medium ONKALO TK4 310-311, 406-407 160/36 of four slickensided fractures. The fractures in the intersection show a P50 3.9 foliation parallel direction, with an intermediate dip. A 10 cm wide zone of soft and weathered rock surrounds the main fracture (36/153°) in the intersection. These fractures have a trace length of approximately 10 m and they are visible in both walls. They contain kaolinite, chlorite, illite, pyrite, graphite and clay fillings. The thickness of the fillings varies from 12 mm to 2 cm; accordingly the Joint alteration numbers (Ja) also varies between 4-8. Chainage 394.00–407.00 contains a brittle fault zone intersection, which comprises several foliation parallel moderately dipping slickenside fractures. These fractures have graphite, chlorite, 430 pyrite, kaolinite and unidentified clay fillings. The thickness of the fillings varies from 10-60 mm and accordingly the Ja value varies from 4-8. In addition to these foliation parallel fractures, also a few vertical slickenside fractures are present with a dip/dip direction of 89/116°, 85/105° and 85/128°. The intersection is visible across the whole tunnel and the main fracture (50/138°) has a 10-50 cm wide zone of soft and weathered rock that surrounds it. Stretching lineations is visible the foliation parallel fracture planes and have a plunge/trend of 70/188°, 02/048° and 12/030°. Some of the vertically dipping fractures show sinistral sense of movement.
TK4, P50: Foliation-parallel fracture oriented 30/145° at x=6792176.574,y=1525871.308,z=2.288 and a foliation-parallel, clay- filled fracture 40/145° at x=6792178.564, y=1525871.507, z=2.136. APPENDIX VIII OL-BFZ115 50 x 50 m ONK-BFI-32440-32800: The brittle fault zone intersection ONK-BFI- High ONKALO 326-327 158/50 32440-32800 consists of several undulating slickensided fault planes with main orientation 50/158°. The deformation zone intersection is visible across the whole tunnel. The right wall contains two separate fault zones that merge to one fault zone in the roof and in the left wall. Fractures are greenish in colour, having graphite, calcite, pyrite, chlorite and unidentified clay fillings, with thickness that varies from 1 mm to 10 cm. In addition there are some shorter fractures (length less than 50 cm) with carbonate and pyrite fillings. Lineation on the slickenside planes has a plunge/trend of 31/112°. Kinematic indicators give the following senses of movement: dextral from above, dextral from the south, and neutral from the east.
OL-BFZ116 100 x 100 m ONK-BFI-41000-41995: The intersection consists of five long High ONKALO 417.5-418.5 065/85 slickensided fracture surfaces with several small slickenside fractures connecting them. These fractures have a subvertical dip and the main fracture has the the dip/dip direction 85/065°. The fractures have epidote, calcite, chlorite, pyrite, kaolinite, biotite, graphite, illite and unidentified clay fillings. The thickness of the filling varies from 0.2-10 mm. Five lineations from slickenside surfaces of the main fracture have plunge/trend 35/330°, 18/251°, 33/286° 10/233° and 21/321°, but the sense-of-shear varies. The foliation is bended in the intersection and it has a steeper dip within the intersection than outside it. Within the intersection there are 5 fractures with a wet surface. The intersection is 431 visible across the whole tunnel.
OL-BFZ117 100 x100 m ONK-BFI-51610-51720: Brittle fault intersection. In right wall there is High ONKALO 516.10-517.20 235/79 a few vertical joints that join in the roof, forming a 30 cm wide KR25 69.17-70.61 intersection. In the left tunnel wall, this intersection consist again of few separated fractures. These undulating slickenside fractures have a greenish/greyish black colour with kl,gr,sk,cc,ka and sv infillings. The thickness of the infilling varies 1-30 mm. The fractures also have some crushed rock fragments with a diameter of 5 mm. The dip/dip direction of the fractures is 79/233° and the lineation has a plunge/trend of 21/036°. Some less than 50 cm long fractures are associated to the main fractures. KR25: single fault plane oriented 74/250° at 69.2 m. APPENDIX VIII OL-BFZ118 167 x 162 m ONK-BFI-71310-71805: Six single slickenside surfaces that cut the High ONKALO 713.10-718.95 041/68 tunnel. Only few SS surfaces combine. Fracture fillings (1-40 mm): SK, CC, KA, KV, KL, CUS, SV. Thick (~5 cm) CC, KV filling in one fracture. Fracture orientations: 83/081, 82/073, 72/086 (right wall). Orientations are similar in the left wall.Left-handed movement observed in PGR vein on the right wall. OL-BFZ119 201 x 274 m ONK-BFI-126900-129400: The core of the intersection is composed of High ONKALO 1293-1294 352/60 a tunnel crossing fracture (TCF) oriented 70/322°. It contains calcite, TK4 P48 1.37-2.97 pyrite, kaolinite and unidentified clay minerals. The intersection also terminates at the location of the core (no "damage zone" after the core). The intersection contains a quite extensive "damage zone" that occurs before the actual core of the fault zone. This "damage zone" contains smooth and slickenside fractures that contain mica (chlorite and biotite) and clay (illite and kaolinite) minerals. The intersection is located in the DGN and therefore the foliation (banding) is irregular, giving no indication of bending of the foliation. Within the DGN there are mica gneiss inclusions, which mainly are more densely fractured than the surrounding rock. The striation measured from the slickenside plane of this fracture, show the plunge/trend of 57/265°. Kinematic indicators give the following senses of movement: sinistral from above, dextral from the east and dextral from the south. BJI_OL-TK4_P48_137_P48_297: Ca. 1.6 m wide fracture zone occurs in the MGN, which contains at least 10 fractures. The main fracture orientations (dip/dip direction) are 65/342° and 85/210°. The rock is broken to small fragments. An altered, completely weathered, 80 cm wide zone in the contact between the MGN and the PGR.
OL-BFZ120 203 x 261 m ONK-BFI-131200-131980: The intersection is composed of one main High ONKALO 1310.76-1312.81 347/85 432 fault (88/337°), which crosscuts the whole tunnel. This fault contains a TK4 P41 1.07-1.88 ca. 10 cm wide section of crushed rock in the left wall, and it branches into two fractures in the right wall. As fracture filling it contains calcite, kaolinite, illite and unidentified clays with a maximum thickness of 10 mm. Striation (7/247°) on this slickenside surface gives the following sense of movement: sinistral from above, neutral from the east and dextral from the south. In addition to the main fault, the intersection contains two slickenside fractures combining with the main fault. One of these shows the same sense of movement as the main fault. However, bended foliation indicates different sense of movement: dextral from above, sinistral from east. The left wall contains a ca. 5 m long “damage zone” before the main fault, which is clearly more fractured than the surrounding rock.The intersection ends to a large vertically dipping slickenside fracture, which covers the whole right wall. TK4: Five fractures with dip/dip direction of 80/335° within the PGR in mapping section P41 at 1.07 - 1.88 m. APPENDIX VIII OL-BFZ121 215 x 140 m ONK-BFI-160800-161300: The Intersection is composed of several High ONKALO 1605.87-1610.03 097/84 subvertical, undulating slickenside fractures. The most densely fractured ONKALO 1799.35-1805.52 area is on the left wall between chainages 1610-1612 where the fracture spacing is ca. 10- 40 cm. The main fractures are oriented 79/096° at 1600 m, 85° at 1605 m, which are tunnel cutting fractures, and 86/075° at 1610 m. There are also some shorter fractures, which have nearly the same orientation as the long ones. Fractures have mostly less than 2 mm filling. The fractures commonly contain calcite, pyrite and chlorite but also epidote, kaolinite and clays exists. ONK-BFI-179700-180900: This intersection is composed of several sub vertical, long, slickensided, tunnel cutting fractures. The main fractures are 72/096° at 1785 m, 72/103° at 1800 m and 62/286° at 1795 m. These fractures typical contain calcite, epidote, chlorite and quartz infillings. Surrounding rock often seems to be slightly epidotized near these fractures.
OL-BFZ122 217 x 248 m ONK-BFI-176450-176650: The intersection consists of two long Medium ONKALO 1764.5-1766.5 007/51 fractures and several shorter ones, which joins the long ones. The long KR22 338.2-339.6 fractures 40/001° in chainage 1760 m and 57/072° in 1765 m joins in the roof and only the former visible in both walls. The latter fracture is seen only in the left wall. There are also some porphyric rock sections particularly around fracture in chainage 1760 m These porphytic areas are ca.10 cm wide and contains average 0,5-1,5 cm wide K-feldspar grains in fine-grained ground mass. Otherwise the rock is unaltered 433 DGN with some mica gneiss/QGN inclusions and some quite narrow PGR veins. There is also some moisture in the roof around the zone. OL_KR22_BFI_33765_34045: Between 338.50 m and 340 m the rock is slightly sheared.The intersection contains 34 fractures and has an average fracture density of 12 fractures/m. At least 10 of these fractures have slickenside surfaces but the drillcore is so shattered near the slickensides that measurements could only be carried out on 3 slickenside fractures (one fracture with dip/dip direction 39/002°). Some old and healed fractures with calcite infillings occur and some mechanical fracturing of them may have occured during the drilling.The direction of the fractures is so variating that no clear fracture sets can be distinguished. The measured slickensides are also randomly orietated. Many fractures have calcite and epidote infillings. No signs of water conductivity were observed. APPENDIX VIII OL-BFZ123 487 x 522 m OL-KR10_BFI 271.47-271.59: A set of parallel slickensides, which Medium KR10 271.5-271.6 124/77 cross-cuts ductile foliation. Presumably slickensides are quite steeply- KR28 568.37-568.69 dipping. On fracture surfaces a slight pryite coatings. KR42 300.32-300.5 KR28: RiIV 568.37-568.69, RiIII 565.2-567.29 ONKALO 1315.0 KR42: RiIII 299.75-302.65 ONK-BFI-132240-132850The intersection is composed of three separate undulating slickenside fractures. These fractures are all sub- vertically dipping but there orientation varies. The main fracture 74/124° at 1315 m is a vertically dipping and sub-parallel with the tunnel, covering the whole right wall. Two conjugate fractures (86/248° at 1320 m and 68/094° at1320 m) from the left wall joins the main fracture in the beginning of the roof on the right hand side. A 10-30 cm wide alteration zone surrounds the rock around these two conjugate fractures. The alteration may be an epidote alteration. Striation (15/190) on the main slickenside surface gives the following sense of movement; dextral from above, neutral from the east and dextral from the south. One of the conjugate fractures shows same sense of movement. The main fracture contains chlorite and pyrite fillings, while the conjugate fractures contain quartz, epidote, chlorite, calcite and unidentified clay fillings. 434 APPENDIX VIII A list of modifications applied for zones in the version 1.0 model
Zone Drillhole intersection, Site Orientation, Drillhole intersection, new model Orientation, Changes made compared to the Model v.0 Model v.0 new model model v.0 (Paulamäki et al. 2006) OL-BFZ001 OL_KR6_BFI_50596_50933 224/11 Removed from the model and replaced by OL-BFZ049.
OL-BFZ002 OL_KR1_BFI_61030_61920 180/17 OL-KR4_ BFI_75770_76270 Average dip Extended to several drillholes: KR2 – OL_KR19_BFI_46475_46532 OL-KR1 611 - 618 direction/dip KR7, KR11, KR12, KR29, KR43. Site- OL_KR19_BFI_47667_47793 OL-KR2_ BFI_60080_60477 165/20 scale fault zone. OL-BFZ062 and OL- OL-KR3_ BJI_47050_47140 BFZ093 are incorporated. OL-KR3_ DSI_47070_47290 OL-KR6_ BJI_46884_46974 OL-KR7_ BFI_68990_69200 OL-KR7_BFI_69410_70210 OL-KR19_ BFI_46475_46532 OL-KR19_ BFI_47667_47793
OL-KR19_ BFI_48461_48892 435 OL-KR43 340 - 341 OL-KR12_ BFI_66480_66580 OL-KR29_ BFI_74570_74730 OL-KR29_ BFI_77651_78102 OL-KR29_ BJI_76280_76365 OL-KR5_ BFI_48178_48335 OL-KR11_ BFI_62502_62647
OL-BFZ003 OL_KR19_BFI_41236_41462 252/38 OL_KR19_BFI_41236_41462 157/25 Re-modelled as a group C fault with an OL_KR5_BFI_40580_40962 orientation 157/25. Extended to OL- KR5replacing OL-BFZ037.
OL-BFZ004 OL_KR13_BFI_31880_32 210/17 - - Incorporated into OL-BFZ099 in OL- APPENDIX IX 500 KR19 and OL-BFZ005 in OL-KR13 OL_KR19_BFI_25335_25 982
OL-BFZ005 OL_KR13_BFI_31880_32500 167/28 OL_KR13_BFI_31880_32500 c. 165/34 OL-BFZ004, OL-BFZ052 and OL- OL_KR14_BFI_44500_44908 OL_KR14_BFI_44500_44908 BFZ075 were incorporated OL_KR15_BFI_44962_45600 OL_KR15_BFI_44962_45600 OL_KR19_BJI_15517_15698 OL_KR19_BJI_15517_15698 OL_KR21_BFI_27577_28100 OL_KR21_BFI_27577_28100
OL-BFZ006 OL_KR19_BJI_11400_11568 235/45 OL_KR19_BJI_11400_11568 235/45 Extended to OL-KR32 OL_KR32_BJI_17526_176 78 OL-BFZ007 OL_KR19B_BJI_1870_2362 108/33 OL_KR19B_BJI_1870_2362 108/33 No changes
OL-BFZ008 OL_KR13_BJI_3385_4604 107/10 OL_KR13_BJI_3385_4604 c. 157/10 Extended to OL-KR2 and OL-KR32 OL_KR2_BFI_4556_4668 OL_KR32_BJI_3975_4270 OL-BFZ009 OL_KR21_BFI_20484_22070 173/26 OL_KR21_BFI_20484_22070 171/27 Extended to OL-KR13 Single fault plane at OL-KR19 OL_KR13_BFI_22025_22596 89.58 m. Single fault plane at OL-KR19 89.58 m.
OL-BFZ010 OL_KR3_BFI_15820_16275 190/50 - - Incorporated into OL-BFZ084. 436
OL-BFZ011 OL_KR9_BFI_14733_14956 - - Extended to OL-KR40. Incorporated into site-scale fault zone OL-BFZ018 OL-BFZ012 OL_KR27_BFI_8450_9650 176/32 OL_KR27_BFI_8450_9650 128/53 Orientation changed
OL-BFZ013 OL_KR27_BFI_12816_12960 080/69 OL_KR27_BFI_12816_12960 080/69 Extended to OL-KR40 OL-KR40 630.39-631.23 RiIII OL-BFZ014 OL_KR27_BFI_33519_33994 Incorporated into OL-BFZ058. OL-BFZ015 OL_KR8_BFI_30393_30675 092/64 OL_KR8_BFI_30393_30675 092/64 OL-BFZ103 is incorporated
OL-BFZ016 OL_KR8_BFI_37600_38300 205/23 OL_KR8_BFI_37600_38300 355/34 Orientation changed
OL_KR23_SFI_4030_5966 232/9 OL_KR23_SFI_4030_5966 232/9 No changes OL-SFZ017 APPENDIX IX
OL-BFZ018 OL_KR4_BFI_8154_8239 150/36 OL_KR11_BFI_11372_11803 c. 139/15 Extended to numerous drillholes and to OL_KR22_BJI_14965_15280 OL_KR14 12-20 the ONKALO access tunnel: site-scale OL_KR24_BJI_11255_11620 OL_KR23 133-139 fault zone. OL-BFZ011 and OL- OL_KR25_BJI_9445_9730 OL_KR24 RiIII 94.02-94.35 BFZ051 incorporated. OL_KR28_BFI_17021_17830 OL_KR23 133-139 OL_KR24 RiIII 94.02-94.35 OL_KR25 BJI_9445_9730 OL_KR28 134-157 OL_KR31 143-145 OL_KR34 RiIV 78.32-78.83 OL_KR35 90-96 OL_KR36 94-96 OL_KR37 RiIII 123.32-123.83 OL_KR38 RiIV 88.15-88.75 OL_KR4_BFI_8154_8239 OL_KR7_DSI_260_4255 OL_KR8_BFI_12040_12370 OL_KR9_BFI_14733_14956 OL_KR40 RiIV 273.87-273.96 ONK_PH4 RiIII 84-85.53 ONK-BFI-93190-96300
OL-BFZ019 OL_KR14_BFI_21755_21913 263/14 - - Incorporated into new site-scale fault 437 zone OL-BFZ080. OL-BFZ020 OL_KR25_BFI_57155_57800 188/46 OL_KR25_BFI_57155_57800 194/33 Orientation slightly changed
OL-BFZ021 OL_KR29_BJI_25147_25184 133/26 - - Incorporated into site-scale fault zone OL-BFZ098. OL-BFZ022 4 single fault planes at OL- 050/21 4 single fault planes at OL-KR29 050/21 No changes KR29 321.1 – 324.8 m 321.1- 324.8 m OL-BFZ023 OL_KR29_BFI_53300_54855 130/39 - - Same as OL-BFZ039. Removed from the model. OL-BFZ024 OL_KR29_BJI_55676_56035 139/47 OL_KR29_BJI_55676_56035 139/47 No changes
OL-BFZ025 OL_KR15_BFI_32308_33200 198/32 OL_KR15_BFI_32308_33200 192/35 Extended to OL-KR2. OL_KR2_BFI_22027_22320 APPENDIX IX OL-BFZ026 OL_KR1_BFI_53860_53963 179/53 - - Incorporated into site-scale fault zone OL-BFZ099. OL-BFZ027 OL_KR19_BFI_29270_29612 180/31 - - Incorporated into site-scale fault zone OL-BFZ099. OL-BFZ028 OL_KR13_BFI_36275_37446 269/82 OL_KR13_BFI_36275_37446 269/82 No changes OL-BFZ029 OL_KR20_BFI_44963_45264 081/28 Incorporated into OL-BFZ065.
OL-BFZ030 OL_KR33_BFI_27591_28043 117/51 OL_KR33_BFI_27591_28043 102/46 Orientation changed due to orientation single fault 102/48 at 199.8 m in KR3 of the faults in the core zone. Extended RiIV at 450.4-450.8 in KR39. to OL-KR3 and OL-KR39. OL-BFZ031 OL_KR33_BFI_28678_28815 107/53 OL_KR33_BFI_28678_28815 109/66 Orientation slightly changed.
OL-BFZ032 OL_KR20_BFI_41059_42445 155/19 - - Incorporated into site-scale fault zone OL-BFZ099. OL-BFZ033 OL_KR2_BFI_47100_47235 065/40 OL_KR2_BFI_47100_47235 125/35 Determined only in OL-KR2, OL_KR14_BFI_44500_44908 intersection in KR14 is incorporated into OL-BFZ005. OL-BFZ034 OL_KR25_BFI_16459_17200 113/7 OL_KR25_BFI_16459_17200 062/10 Orientation changed. Single fault plane at OL-KR28 179.13 OL-BFZ035 OL_KR31_BJI_4070_4400 165/89 OL_KR31_BJI_4070_4400 166/84 Orientation slightly changed.
OL-BFZ036 OL_KR14_BFI_46985_47623 118/40 OL_KR14_BFI_46985_47623 118/40 No changes made. 438 OL-BFZ037 OL_KR33_BFI_27591_28043 098/45 - - Intersection in OL-KR33 incorporated OL_KR5_BFI_40580_40962 into OL-BFZ030. Connection to OL- OL_KR19_BFI_48461_48892 KR5 and OL- KR19 removed. OL-BFZ038 OL_KR20_BFI_41059_42445 174/28 - - Incorporated into site-scale fault zone OL-BFZ099. OL-BFZ039 OL_KR29_BFI_53300_54855 130/40 OL_KR29_BFI_53300_54855 130/40 No changes made. Single fault plane in OL-KR7 Single fault plane in OL-KR7 at 473.92 at 473.92 m m OL-BFZ040 OL_KR3_BJI_4630_4880 155/37 OL_KR3_BJI_4630_4880 146/45 Extended to OL-KR39. Orientation RiIV at 182.52-184.5 m in KR39. slightly changed. OL-BFZ041 OL_KR13_BFI_16378_17647 153/41 OL_KR13_BFI_16378_17647 156/31 Extended to investigation trench OL- OL_KR6_BFI_480_1395 TK8 and drillholes KR6, KR12, KR19,
OL_KR19B_BFI_4045_4505 KR32, KR41 and KR42. Replaces OL- APPENDIX IX OL-TK8_BJI_300_510 BFZ047 in KR6 and KR19. Connected Single faults at 283.9-291.2 m in KR12 to surface magnetic lineament Single faults at 163.7-174.6 m in KR32 SURFMAGN0051. RiIII/RiIV at 213.45-214.55 m in KR41 RiIII 310.01-314.15 m and RiIV at 314.15-315.57 m in KR42 OL-BFZ042 OL_KR13_BFI_44550_46800 129/35 - - Incorporated into site-scale fault zone OL-BFZ099. OL-BFZ043 OL_KR10_BFI_27147_27159 115/78 OL_KR10_BFI_27147_27159 c. 124/77 Extended to OL-KR28, OL-KR42 and KR28 RiIV 568.37-568.69 the ONKALO tunnel. KR42 RiIII 299.75-302.65 ONK_BFI_132240_132850 OL-BFZ044 OL_KR19_BFI_9945_10309 146/37 OL_KR19_BFI_9945_10309 146/37 No changes made. OL-BFZ045 OL_KR13_BFI_40941_42389 140/37 OL_KR13_BFI_40941_42389 101/67 Orientation changed due to orientation of the faults in the core zone. OL-BFZ046 OL_KR15_BFI_49350_49650 130/83 OL_KR15_BFI_49350_49650 130/83 No changes made. OL-BFZ047 OL_KR6_BFI_480_1395 154/19 - - Incorporated into OL-BFZ041. OL_KR19B_BFI_4045_4505 OL-BFZ048 OL_KR8_BFI_34848_35265 155/42 OL_KR8_BFI_34848_35265 155/42 Extended to OL-KR27, where OL- OL-KR27_BFI_29280_29410 BFZ057 and OL-BFZ061 incorporated RiIV at 401.34-402.13 in KR40. into OL-BFZ048. Extended to OL- KR40. OL-BFZ049 OL_KR6_BFI_50596_50933 090/20 OL_KR6_BFI_50596_50933 090/20 No changes made. 439 OL-BFZ050 OL_KR16_BFI_11968_13469 112/50 OL_KR16_BFI_11968_13469 112/50 Extended to OL-KR32. OL_KR17_BFI_12350_13092 OL_KR17_BFI_12350_13092 RiIII at 86.79-88.15 m in KR32 with one measured fault 111/45. OL-BFZ051 OL_KR4_BFI_8154_8239 105/8 - - Incorporated into site-scale fault zone OL_KR8_BFI_13822_13994 OL-BFZ018 OL-KR24: ca. 16 fractures at 94-95 m OL-BFZ052 OL_KR15_BFI_44962_45600 170/44 Incorporated into OL-BFZ005. OL-BFZ053 OL_KR27_BFI_30256_32607 133/84 OL_KR27_BFI_30256_32607 120-134/62-76 Extended to OL-KR40. RiIV at 789.58-796.69 m in KR40
OL-BFZ054 OL_KR27_SFI_33385_34842 121/56 - - Incorporated into OL-BFZ058 APPENDIX IX OL_KR27_BFI_33519_33994 OL-BFZ055 OL_KR27_BFI 4270943342 130/72 OL_KR27_BFI 4270943342 138/78 Extended to OL-KR23 and OL-KR40. OL_KR27_SFI_ 42600_43990 OL_KR27_SFI_ 42600_43990 OL-KR23 Core loss 175.97-176.83 OL-KR40 RiIV 919.36-920.79 OL-BFZ056 OL_KR27_SFI_27485_28824 148/45 OL-KR2 25.45 – 25.75 120-150/10-15 Extended to numerous drill holes and to OL_KR27_BFI_27751_28440 OL-KR10 76.5 – 77 the ONKALO access tunnel: site-scale OL_KR11_BFI_11372_11803 zone. OL-KR12 39.1 - 40.5 OL-KR14 50 –51 OL_KR22_BFI_13880_14605 OL-KR23 RiIII 195.33 – 196.11 OL_KR24_BJI_11255_11620 OL-KR25 119 – 120 OL_KR27_BFI_27751_28440 OL-KR28_BFI_17021_17830 OL_KR30_BFI_8109_8348 OL-KR31 RiIII 174.63 – 175.36 OL_KR36_BFI_15360_15680 OL-KR37 168 – 169 OL-KR38 core loss 122.22 – 122.54 OL-KR9 197 – 198
OL-KR40 RiIII 283.73 – 284.78 440 OL-KR42 RiIII 57.7 – 58.18 OL-KR4 116.1 – 116.3 ONK-PH5 core loss 57.09 – 57.2 ONK-BFI-104500-110850
OL-BFZ057 OL_KR27_BFI_29270_29612 170/25 - - Incorporated into OL-BFZ048. OL-BFZ058 OL_KR22_BFI_7790_10300 120/40 OL_KR22_BFI_7790_10300 119/47 Extended to OL-KR27, OL-BFZ054 OL_KR31_BFI_8600_9000 OL_KR27_BFI_ 33519_33994 incorporated. OL_KR31_BJI_10250_10800 OL_KR31_BFI_10250_10800
OL-BFZ059 OL_KR22_BFI_13880_14605 140/47 OL_KR22_BFI_13880_14605 145/55 Orientation slightly changed.
OL-BFZ060 OL_KR22_BFI_18845_20050 130/34 OL_KR22_BFI_18845_20050 c. 127/32 No changes. OL_KR28_BFI_17021_17830 OL_KR28_BFI_17021_17830 APPENDIX IX
OL-BFZ061 OL_KR27_BFI_29270_29612 127/59 - - Incorporated into OL-BFZ48. OL-BFZ062 OL_KR5_BFI_48178_48335 142/35 - - Incorporated into site-scale fault zone OL-BFZ002. OL-BFZ063 OL_KR14_BFI_44500_44908 266/66 OL_KR14_BFI_44500_44908 266/66 Extended to OL-KR2. single faults at 396.1-396.9 m in OL- KR2 OL-BFZ064 OL_KR2_BFI_60080_60477 158/40 OL_KR2_BFI_60080_60477 158/40 Extended to OL-KR1. OL_KR1_BFI_64040_64220. OL-BFZ065 OL_KR19_BFI_53327_53591 099/38 OL_KR19_BFI_53327_53591 099/38 Extended to OL-KR20 replacing OL- OL_KR20_BFI_44963_45264 BFZ029.
OL-BFZ066 A cluster of 6 faults of fault 181/49 A cluster of 6 faults of fault group B at 181/49 No changes made. group B at 46.65-53.76 m in 46.65-53.76 m OL-KR4 OL-BFZ067 OL_KR12_BFI_7375_8020 120/36 OL_KR12_BFI_7375_8020 150/45 Extended to OL-TK4. Orientation OL-TK4_P17_110_P17_200. changed to the orientation of the surface magnetic lineament SURFMAGN0012. OL-BFZ068 OL_KR20_BJI_7008_7290 158/42 OL_KR20_BJI_7008_7290 158/42 No changes made. OL-BFZ069 OL_KR13_BFI_47500_48052 056/54 OL_KR13_BFI_47500_48052 055/50 Orientation slightly changed. OL-BFZ070 OL_KR12_BFI_50500_50600 145/22 OL_KR12_BFI_50500_50600 145/22 Extended to OL-KR10. 441 RiIII at 499.5-499.9 m in OL-KR10 OL-BFZ071 OL_KR15_BFI_32308_33200 170/26 Incorporated into OL-BFZ025. OL-BFZ072 OL_KR13_BFI_24584_25500 143/41 OL_KR13_BFI_24584_25500 157/42 Orientation changed due to orientation of the faults in the core zone. OL-BFZ073 OL_KR7_BFI_22701_22880 150/47 - - Incorporated into site-scale fault zone OL_KR7_DSI_22701_23035 OL-BFZ098. OL-BFZ074 OL_KR8_BJI_8000_8380 043/51 OL_KR8_BJI_8000_8380 043/51 No changes made. OL-BFZ075 OL_KR14_BFI_44500_44908 172/32 - - Incorporated into OL-BFZ005. OL_KR15_BFI_44962_45600 OL-BFZ076 OL_KR13_BFI_44550_46800 148/36 - - Incorporated into site-scale fault zone OL-BFZ099. OL-BFZ077 OL_KR7_BFI_40925_41040 170/45 - - Incorporated into OL-BFZ084.
OL-BFZ078 OL_KR19_BFI_17458_18675 137/33 OL_KR19_BFI_17458_18675 104/35 Orientation changed due to orientation APPENDIX IX of the faults in the core zone. OL-BFZ079 OL_KR5_BFI_26945_27068 161/27 - - Incorporated into site-scale fault zone Single group B faults in KR20 OL-BFZ099. at 412 m OL-BFZ080 OL_KR25_BJI_36931_37320 120/23 OL-KR1 175 - 188 Average dip Site-scale fault zone labelled OL- OL-KR2 207 - 212 direction/dip BFZ080 and covering drillholes KR1, OL_KR10_BFI_ 32600_ 32745 140/20 2, 4, 7-10, 12-15, 22-25, 27-29, 38-39, OL-KR12 271 - 273 40 and 42. OL-KR13 188.5 - 190.5 OL_KR14_ BFI_21755_21913 OL-KR15 201 - 203 OL_KR22_BJI_42335_42565 OL-KR23 448 - 460.25 OL-KR24 395 - 399 OL_KR25_BJI_36931_37320 OL-KR27 545 - 549.6 OL-KR28 440 - 448 OL_KR29_BJI_33355_33775 OL_KR38_BJI_37253_39262 OL-KR39 178 - 188 OL-KR4 365 - 370.57 OL-KR40 625 - 631.24
OL_KR7_BFI_28570_28640 442 OL_KR7_BFI_28732_28870 OL_KR8_BJI_54200_56200 OL_KR9_BFI_47676_47935 OL-KR42 272.8 - 279.6
OL-BFZ081 OL_KR10_BFI_10970_11045 121/47 OL_KR10_BFI_10970_11045 135/20 Orientation changed due to orientation Single long fracture in ONKALO of the faults in the core zone. chainage 1163 m Connected to tunnel crosscutting fracture in ONKALO. OL-BFZ082 OL_KR19_BJI_20234_20286 161/23 OL_KR19_BJI_20234_20286 170/45 Orientation changed due to orientation of the faults in the core zone. OL-BFZ083 OL_KR19_BFI_20986_21153 169/45 OL_KR19_BFI_20986_21153 169/45 No changes made. OL-BFZ084 OL_KR3_BFI_15820_16275 182/64 OL_KR3_BFI_15820_16275 182/60 Extended to drillholes OL-KR1, OL- OL_KR1_BFI_10851_11036 KR7, OL-KR39 and investigation APPENDIX IX OL_KR7_BFI_40925_41040 trench OL-TK2. RiIV at 186.55-187.52 in OL-KR39 OL-TK2 BFI_OL- TK2_P6_854_P6_904 OL-BFZ085 OL_KR1_BFI_10851_11036 185/58 - - Incorporated into OL-BFZ084. OL-BFZ086 OL_KR17_BFI_12350_13092 141/37 OL_KR17_BFI_12350_13092 149/34 Extended to OL-KR15. OL_KR15_BJI_14820_14880 OL-BFZ087 OL_KR19_BFI_17458_18675 073/24 OL_KR19_BFI_17458_18675 073/24 No changes made. OL-BFZ088 OL_KR10_BFI_10970_1104 069/45 - - Incorporated into OL-BFZ081. OL-BFZ089 OL_KR15_BFI_32308_33200 152/84 - - Incorporated into OL-BFZ025. OL-BFZ090 OL_KR14_BFI_46985_47623 137/71 - - Incorporated into OL-BFZ036 (KR14) OL_KR15_BFI_49350_49650 and OL-BFZ046 (KR15). OL-BFZ091 OL_KR29_BFI_84830_85197 020/47 OL_KR29_BFI_84830_85197 020/47 No changes made. OL-BFZ092 OL_KR13_BFI_36275_37446 111/38 OL_KR13_BFI_36275_37446 109/40 No significant changes. OL_KR19_BFI_20986_21153 OL_KR19_BFI_20986_21153 OL_KR20_BJI_17760_18105 OL_KR20_BJI_17760_18105
OL-BFZ093 OL_KR4_BFI_79100_79200 139/29 - - Incorporated into site-scale fault zone OL_KR7_BFI_68990_69200 OL-BFZ002 OL_KR29_BFI_74570_74730 OL-BFZ094 OL_KR12_BFI_58240_58410 117/74 OL_KR12_BFI_58240_58410 117/74 No changes made. OL-BFZ095 OL_KR19_BJI_7506_7730 093/13 OL_KR19_BJI_7506_7730 093/13 No changes made. 443 OL-BFZ096 OL_KR12_BFI_20245_20600 244/85 OL_KR12_BFI_20245_20600 244/85 No changes made. OL-BFZ097 A set of faults (13 156/47 A set of faults (13 slickensides) at 156/47 No changes made. slickensides) at 51.65-54.52 m 51.65-54.52 m dominated by group E dominated by group E faults. faults. OL-BFZ098 OL_KR1_BJI_14118_14395 140 – 160/15-30 OL_KR1_BJI_14118_143.95 Average Extended to several drillholes: site- OL_KR14_BFI_21755_21913 OL_KR10_BFI_27147_27159 orientation c. scale fault zone. BFZ021 and BFZ021 OL_KR22_BFI_33765_34045 OL-KR14 180 - 186 155/20 are incorporated. OL_KR29_BJI_33046_33086 OL-KR2 98 - 125 OL_KR3_BJI_4630_4880 OL-KR22 385 - 393.06 OL_KR4_BFI_31340_31615 OL-KR23 422 - 430 OL_KR7_BFI_28732_28870 OL-KR24 325 - 335 OL_KR25_BFI_34700_35225
OL-KR27 505 - 520 APPENDIX IX OL-KR28 388 - 390 OL_KR29_BJI_25147_25184 OL_KR38_BFI_30732_30855 OL-KR39 146.88 - 151.1 OL_KR4_BFI_31340_31615 OL-KR40 600 - 612.85 OL_KR7_BFI_22701_22880 OL_KR8_BJI_45047_45460 OL_KR9_BJI_44420_44510 OL-KR42 191.07 - 198.8 OL-KR12 159 - 169 OL-KR15 166 - 170 OL-KR16 150 - 152.5
OL-BFZ099 OL_KR1_BFI_52520_52620 160-170/30-40 OL_KR4_ BFI_75770_762.70 160-170/30-40 Some drillhole intersections changed, OL_KR11_BFI_62502_62647 OL_KR1_ BFI_525.20_526.20 extended to OL-KR43. Site-scale fault OL_KR12_BFI_58240_58410 OL_KR1_ BFI_538.60_539.63 zone. BFZ004, BFZ026, BFZ 027, BFZ OL_KR13_BFI_44550_46800 OL_KR2_ BFI_47100_47235, 032, BFZ 038, BFZ 042, BFZ 076 and OL_KR19_BFI_25335_25982 OL_KR2_DSI_46749_47380 BFZ 079 were incorporated. Connected OL_KR2_BFI_50404_50795 OL_KR3_ BJI_47050_47140, to linked lineament LINKED0255 OL_KR20_BFI_44963_45264 OL_KR3_DSI_47070_47290 (GTKMAGN 0126, TOPO O069) OL_KR29_BFI_84830_85197 OL_KR6_ BFI_12322_12945
OL_KR33_BFI_27591_28043 OL_KR6_ BFI_11753_11805 444 OL_KR33_BFI_28678_28815 OL_KR7_ BFI_68990_69200 OL_KR4_BFI_75770_76270 OL_KR7_ BFI_69410_70210 OL_KR5_BFI_26945_27068 OL_KR19_ BFI_25335_25982, OL_KR5_BFI_27897_28244 OL_KR19_BJI_23839_25860 OL_KR6_BFI_11753_11805 OL_KR33_ BFI_27591_28043 OL_KR6_BFI_12322_12945 OL_KR33_ BFI_28678_28815 OL_KR7_BFI_68990_69200 OL_KR43 100 - 101 OL_KR7_BFI_69410_70210 OL_KR13 BFI__44550_46800 OL_KR13_ BFI_47500_48052 OL_KR20 BFI__41059_42445 OL_KR20_ BFI_42690_43114 OL_KR13 BFI__58240_58410 OL_KR5 BFI__26945_27085 OL_KR5_ BFI_27897_28244 APPENDIX IX OL_KR11 BFI__62502_62647 OL_KR29_ BFI_74570_74730 OL_KR29_ BFI_77651_78102, OL_KR29_BJI_76280_76365 OL.BFZ100 OL_KR25_BJI_9445_9730 c. 090-120/55- OL_KR22_BFI_33765_34045 098/67 Extended to OL-KR22 and ONKALO OL_KR26_BJI_9580_9825 70 OL_KR25_BJI_9445_9730 chainages 900.2-906.4, 1592.9-1595.0 OL_PH1_BFI_15164_15432 OL_KR26_BJI_9580_9825 and 1819.0-1831.0 m. OL_TK11_BFI_C20_S25 OL_PH1_BFI_15164_15432 OL- OL_TK11_BFI_C20_S25 TK7_P8_BFI_347_P8_400 OL-TK7_P8_BFI_347_P8_400 ONK_BFI_12850_12930 ONK_BFI_12850_12930 ONK_BFI_52150_52300 ONK_BFI_52150_52300 ONK_BFI_90020_90640 ONK_BFI_159290_159500 ONK_BFI_181900_183100 OL-BFZ101 ONK_BFI_7000_7190 c. 116/11 ONK_BFI_7000_7190 c. 140/15 Orientation slightly changed. OL_PH1_97.77 _ 99.85 OL_PH1_97.77 _ 99.85 OL-PP40 17.85 – 18.53 OL-PP40 17.85 – 18.53 OL-PP41 27.10 – 27.89 OL-PP41 27.10 – 27.89 OL-PR5 4.24 – 4.64 OL-PR5 4.24 – 4.64
OL-PR6 5.55 – 6.00 OL-PR6 5.55 – 6.00 445 OL-PR7 7.56 – 8.09 OL-PR7 7.56 – 8.09 OL-PR8 11.90 – 12.30 OL-PR8 11.90 – 12.30 OL-BFZ102 ONK_DSI_24000_28230 110-170/40-60 ONK_DSI_24000_28230 ONK_DSI_44970_45330 ONK_DSI_44970_45330 OL-BFZ103 OL_KR6_BFI_50596_50933 097/61 - - Incorporated into OL-BFZ015. OL-BFZ104 OL_KR2_BFI_103930_104095 189/43 New OL-BFZ105 OL_KR11_BFI_89550_89840 189/43 New 0L-BFZ106 OL_KR22_BFI_4280_7315 057/48 New. Connected to surface magnetic OL_KR27_BFI_8450_9650 lineament SURFMAGN0012. OL-BFZ107 OL_KR12_BFI_74510_75094 188/52 New OL-BFZ108 OL_KR6_BFI_36622_36710 180/30 New OL-BFZ109 BJI_OL-TK2_P25_260_P25_300 157/33 New. Connected to linked lineament BJI_OL-TK2_P25_990_P25_1010 LINKED 0474 (SURFMAGN 0166, APPENDIX IX BJI_OL-TK2_P25_1135_P25_1195 TOPO 0118). BJI_OL-TK2_P26_360_P26_686 OL_KR7_BJI_8265_8330 OL-BFZ110 BJI_OL-TK8_P71_130_P71_250 210/40 New. Connected to topographic OL_KR13_BFI_27840_28810 lineament TOPO 0074. OL_KR19_BJI_12263_12492 OL-BFZ111 KR38_BJI 22.75-24.95 237/77 New
OL-BFZ112 ONK-BFI-24250-28700 009/17 New ONK-HGI-24000-28230 OL-BFZ113 ONK-BFI-29200-29500 273/42 New OL-BFZ114 ONK-BFI-30950-31100 160/36 New ONK-BFI-39400-40700 OL-BFZ115 ONK-BFI-32440-32800 158/50 New OL-BFZ116 ONK-BFI-41000-41995 065/85 New OL-BFZ117 ONK-BFI-51610-51720 235/79 New OL-BFZ118 ONK-BFI-71310-71805 041/68 New OL-BFZ119 ONK-BFI-126900-129400 352/60 New BJI_OL-TK4_P48_137_P48_297 OL-BFZ120 ONK-BFI-131200-131980 347/85 New OL-BFZ121 ONK-BFI-160800-161300 097/84 New ONK-BFI-179700-180900 446 OL-BFZ122 OL_KR22_BFI_33765_34045 007/51 New ONK-BFI-176450-176650 OL-BFZ123 KR10_BFI 271.47-271.59 124/77 New ONK-BFI-132240-132850 APPENDIX IX OLKILUOTO
Site Model V.1
Vertical Section X = 1525000
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss 447 Pegmatitic granite Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1525200
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss 448 Pegmatitic granite Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1525400
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 449 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1525600
LEGEND
Veined gneiss Diatexitic gneiss 450 Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1525800
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite 451 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1526000
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 452 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1526200
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 453 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1526400
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 454 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1526600
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 455 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1526800
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 456 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section X = 1527000
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 457 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6791500
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 458 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6791700
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 459 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6791900
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite 460 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6792100
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 461 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6792300
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 462 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6792500
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 463 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6792700
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 464 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6792900
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 465 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6793100
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 466 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6793300
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 467 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Vertical Section Y = 6793500
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss
Pegmatitic granite 468 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = 0
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 469 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -100
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 470 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -200
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 471 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -300
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 472 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -400
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 473 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -500
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 474 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -600
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 475 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -700
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 476 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -800
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 477 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1
Planview Z = -900
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase Brittle deformation zone 478 Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1 Site-scale zones
Vertical Section BFZ099 X = 1525600
LEGEND
Veined gneiss BFZ098 Diatexitic gneiss Mica gneiss TGG gneiss BFZ080 Pegmatitic granite 479 BFZ002 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1 Site-scale zones
BFZ018 Vertical Section X = 1526000 BFZ056 LEGEND
BFZ099 Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite BFZ098 480 BFZ002 Diabase BFZ080 Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1 Site-scale zones
Vertical Section BFZ018 X = 1526400 BFZ056 LEGEND
BFZ098 Veined gneiss Diatexitic gneiss Mica gneiss BFZ099 TGG gneiss Pegmatitic granite BFZ080 481 Diabase Brittle deformation zone Projection of ONKALO
BFZ002 Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1 Site-scale zones
Vertical Section Y = 6792100 BFZ018 LEGEND BFZ098 BFZ056 Veined gneiss BFZ080 Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite 482 Diabase Brittle deformation zone Projection of ONKALO
BFZ099
BFZ002 Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1 Site-scale zones
Vertical Section BFZ018 Y = 6792500 BFZ056 LEGEND
Veined gneiss Diatexitic gneiss BFZ098 Mica gneiss BFZ080 TGG gneiss Pegmatitic granite 483 Diabase Brittle deformation zone Projection of ONKALO BFZ099 BFZ002 Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1 Site-scale zones
Vertical Section Y = 6792900
LEGEND
Veined gneiss
BFZ099 Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite 484 BFZ002 Diabase Brittle deformation zone Projection of ONKALO Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1 Site-scale zones
Planview BFZ099 Z = -100
LEGEND
Veined gneiss Diatexitic gneiss Mica gneiss TGG gneiss Pegmatitic granite Diabase BFZ098 Brittle deformation zone 485 Projection of ONKALO
BFZ056
BFZ018 Vertical andhorizontalprofiles of thefaultzones APPENDIX X OLKILUOTO
Site Model V.1 Site-scale zones
Planview Z = -500
LEGEND
Veined gneiss Diatexitic gneiss BFZ002 Mica gneiss TGG gneiss Pegmatitic granite Diabase BFZ099 Brittle deformation zone 486 Projection of ONKALO
BFZ080
BFZ098 Vertical andhorizontalprofiles of thefaultzones APPENDIX X 487
Tables for the definition of influence zone in each drill hole intersection
For each modelled site-scale fault zone an influence zone has been defined. The influence zone intersection has been interpreted based on WellCAD-logs and the main characteristics of the zone are described in the following tables. Each table describes for each drill hole intersection the upper and lower limit of the main modelled core, the upper and lower limit of the influence zones around the main modelled core and description of the main characteristics for the intersection in question. The main modelled core is the one used for building the solid APPENDIX XI describing the modelled fault zone in 3D modelling. The influence zone may contain additional cores, which are described in the description column. The upper influence zone can also be called hanging wall and the lower influence zone footwall. The whole influence zone includes both the upper and the lower influence zones. BFZ002 Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR4 756 764 750 820 6 8 56 70 Zone includes 3 BFI sections and 4 RiIII-IV -sections. The main core is the upper one with BFI- and RiIII-IV- sections. Most of the zone has fracture kaolinisations and fracture controlled or pervasive illitisation. Increased fracturing and slickensided-fractures describe the zone. They exist concentrated around the core and as single slickensided fractures in the whole zone. The whole zone has long normal and P-wave velocity anomalies mainly decribing the cores. The hydraulic conductivity has increased at the main core. The zone is located at the beginning of the larger pegmatite body.
KR1 611 618 593 649 18 7 31 56 The zone is described by increasing fracturing and alteration. The main modelled zone consists of RiIII-section with core loss, increased fracturing, elevated hydraulic conductivity and pervasive illitisation and kaolinisation. While major part of the main core is missing, consequently also also geological section interpretation is missing. Slickensided fractures are exceptionally rare for this zone, but if existing are located mainly close to the cores and in the lower altered section. The upper RiIII-section at 594 m with core loss is also slightly hydraulically conductive. Another BFI section at 640-642 m coincides with RiIII-section. This section is covered by section of pervasive kaolinisation, illitisation and fracture controlled sulphidisation at 636-648 m. This altered section covers also two other RiIII-sections, one int the beginning of the altered section and one at 645 m. Finally, at the end of altered section a concentration of slickensided fractures exists. The rock types of the zone changes from the upper limit of the influence zone downwards from veined gneiss to diatexitic gneiss to TTG gneiss and again veined gneiss. The upper part of the zone can be clearly seen in long normal and short normal anomalies as well in P-wave veocity anomaly, but the P-wave velocity anomaly describes the lower part of the influence zone better. A special phenomenom is the decreasing TDS-value from the beginning of the influence zone to the end of the zone. 488 KR2 600 607 568 643 32 7 36 75 The main core, at 600-607 m, consists of BFI together with 2 RiIII-sections, clearly increased fracture frequency, pervasive illitisation and fracture controlled kaolinitisation at 598-622 m and increased hydraulic conductivity. The whole influence zone is determined based on increased number of slickensided fractures and slightly elevated hydraulic conductivity not only in cores but in the whole influence zone. Based on long normal and short normal anomalies the zone is from 502 to 715 m, but has been cut off based on slickensided fractures and elevated hydraulic conductivity. Additional core section exists at 631-633 m (RiIII and elevated hydraulic conductivity). The upper limit of the influence zone is quite artificial! The main rock type of the zone is diatexitic gneiss, but short sections of pegmatitic granite exists at and close to the main core section.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR3 470 473 462.5 474 7.5 3 1 11.5 The whole influence zone includes short sections of HSI and BJI, increased number of slickensided fractures, pervasive kaolinitisation and fracture controlle illitisation. The main modelled core section is BJI section without any Ri-section. The HSI section at 471-473 m covers it. Both alteration types continue and cover a large area of 430-502 m. However, this influence zone has not been extended to cover the whole area, but more presice part of the core sections and slickensided fractures. The alteration is covered in the alteration model. lGeophysical anomalies are not clear and are probably affected by the large altered area. The upper limit of the influence zone begins right under the pegmatitic unit being totally in a veined gneiss.
KR6 468 471 435 479.5 33 3 8.5 44.5 The main modelled core section is BJI, which coincides with RiIII-section and elevated hydraulic conductivity. APPENDIX XI Another RiIII-section at the end of the influence zone consists of RiIII-section with core loss, concentration of slickencided fractures and elevated hydraulic conductivity. Both core sections are covered by section of fracture controlled kaolinisation and illitisation at 463-477 m. Slightly elevated hydraulic conductivity is also measured at 440 m in the place of somewhat increased fracturing and few slickensided fractures. Geophysical anomalies, long normal and short normal indicate the whole influence zone, but the anomaly is larger than this zone. The upper limit of the zone is located in pegmatitic granite, which shortly changes to veined gneiss, which is the main rock type. The main feature of the zone is increased fracturing and slickensided fractures. KR7 690.5 692.02 685 724 5.5 1.52 31.98 39 The main modelled core section consists of BFI and RiIII-V-section also covered by pervasive illitisation between 688-695m. Another BFI section underneath the main core covers HGI section and two RiIII-sections at the both ends of BFI. Yet three more RiIII-sections are located at the influence zone, but they are not mapped as geological core sections. Fracturing has increased in the whole influence zone. Another section of pervasive illitisation at 706-717 m cover two of the three RiIII-sections. Slickensided fractures continue through the whole influence zone. The major part of the zone is located at veined gneiss, but both ends are characterised by pegmatitic granites changing with gneisses.This section at the drill hole has not been measured because drill hole was plugged by dropping stones from the drill hole walls. Anyhow, based on drilling information this section is conductive.
Description of the zone of influence Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
Hole to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR19 464 466 440 494 24 2 28 54 The main modelled core consists of BFI sections and RiIV-section with increased fracturing. The main core is located on a short section of mica gneiss inside the pegmatitic granite. The main core section is covered by pervasive illitisation and fracture controlled sulphidisation at 461-472 m. The main core is not hydraulically conductive, but the lower end of the altered section has slightly elevated conductivity and from the upper end of the section to the upper limit of the influence zone hydraulic conductivity has been elevated without any special geological feature except sparce fracturing. The whole zone can be seen in long normal and short normal anomalies, but the anomaly seems to continue downwards after the zone. The main rock type at the upper part of the influence zone is veined gneiss, which changes trough varying pegmatitic granite, quartz gneiss and diatexitic gneiss to mica gneiss.
KR43 340 341 no data no data no data 1 no data no data no data 489
KR12 665 673 643.5 675.5 21.5 8 2.5 32 The main modelled core is BFI-sections together with RiIII-V-section and core loss at the same place. The main core has also elevated hydraulic conductivity and conetrations of slickensided fractures around it. Additional RiIII-section five meters deeper has no hydraulic conductivity, but increase of slickensided fractures around it. The upper most core at 649 is also RiIII-section with elevated conductivity as well as the lower one at 654. The whole zone is covered by large section of pervasive illitisation and fracture controlled kaolinisation. Hydraulic conductivity increases in the core section. The whole zone can be seen in short normal and long normal anomalies and the P-wave velocity anomaly describes the core sections. Pervasive illitisation continues in the both sides of the zone, but because geophysical anomaly and clearly increased fracturing are decreased has influence zone not been continued. There are some single slickensided fractures above the zone and the continuous pervasive illitisation until the modelled upper splay of the same zone. Probably both these sections have affected each others and have some connection in this part of the rock and the limit of the influence zone is quite artificial. Pervasive illitisation has been shown in the alteration model. The main rock type changes from pegmatitic granite to veined gneiss to varying diatexitic gneiss and pegmatite and finally ends at diatexitic gneiss.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR29 777 781 775 786 2 4 5 11 The main modelled core section consists of RiIV-V sections together with two short sections of fracture
controlled illitisation. Water conductive fractures are located at or close by the core. Slickensided fractures don't APPENDIX XI exists at this intersection. It also looks quite meager compared to other intersections of this zone. Core section can be clearly seen in P-wave velocity anomaly. There are another BFI-core and RiIII-V -section 10 m above this and further another RiIII 15 m above, but these are not included into this zone because rock between these cores is almost fractureless. KR5 481 483.5 460 510 21 2.5 26.5 50 The main modelled core section is both BFI section with coinciding RiIV -section and concentration of slickensided fractures. The main core section is covered by pervasive illitisation and fracture controlled kaolinisation, but no elevated hydraulic conductivity is measured. Another RiIII-section above the main core has elevated hydraulic conductivity. Also an elevated hydraulic conductivity at 460 m is included into this influence zone. The fracturing has increased around the core sections and slickensided fractures are characteristical for the whole influence zone. The geophysical anomaly is difficult to interpret for this zone. TDS-value is elevated in both conductive sections! The main rock type is veined gneiss.
KR11 623 627 615 650 8 4 23 35 The main modelled core consists of BFI section with coinciding RiIII- and RiIV-sections and clear concentration of slickensided fractures and minor elevation in hydraulic conductivity. The fracturing has not increased clearly except around the core, but few concentrations of slickensided fractures exists. This intersection is not altered at all as the rest of the drill hole intersections belonging to this zone. The geophysical anomaly, long normal and short normal minimum, shows clearly the core sections.The main rock type is veined gneiss.
Averages 16.2 4.5 22.7 43.5
BFZ099 Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone 490 KR4 756 764 750 820 6 8.0 56 70 Zone includes 3 BFI sections and 4 RiIII-IV -sections. The main modelled core is the upper BFI- and RIIII-IV- sections with slightly increased hydraulic conductivity. The second BFI section at 770 is very short section without hydraulic conductivity or any Ri-sections. The following RiIII-section at 775-777 is RiIII-section with minor increase in hydraulic conductivity. The lowest BFI section coincides with the RiIII-section and covers a short section of mica gneiss inside the larger pegmatitic unit. The lower most RiIII-section is also in a mica gneiss covered by setion of pervasive illitisation and fracture controlled kaolinisation at 802-811 m. In addition a very minor elevation in hydraulic conductivity has been measured. Most of the zone has fracture controlled kaolinitisation and illitisation or pervasive illitisation. Increased fracturing and slickensided fractures describe the zone. Slickensided fractures are mainly concentrated around the core and as single slickensided fractures in the whole zone. The whole zone is visible in geophysical anomalies, mainly long normal, short normal, and P- wave velocity minimum is mainly concentrated on core sections. The hydraulic conductivity has slightly increased at the main core. The influence zone is located at the beginning of the larger pegmatite body starting at the veined gneiss and through short sections of stromatic, diatexitic and mica gneiss into pegmatitic granite
KR1 524 526.2 490 545 34 2.2 18.8 55 The whole influence zone includes 3 RiIII-sections and two BFI-sections. The main modelled core is BFI section with RiIII-section and core loss. Hydraulic conductivity has elevated in the main core and around it. Another RiIII-section with core loss is located above the main modelled core at the contact of pegmatitic granite and veined gneiss. A minor hydraulic conductivity has been measured at it. Another BFI section together with RiIII- section is at 538-540. This core section and it's surroundings are hydraulically conductive. Slickensided fractures are concentrated around the core sections but single ones also exists between the cores. Geophysical anomalies, long normal and short normal, are visible at the main core section, but P-wave velocity reacts also to the whole zone. Very large influence zone based on slickensided fractures and alteration. The APPENDIX XI upper limit of the influence zone begins right under the large pegmatitic unit located mainly in a veined gneiss. There are short sections of pegmatitic granites, varing from 2 to 7 meters, above the upper RiIII-section. KR2 471 473 458 492 13 2.0 19 34 The main modelled core section is BFI section with RiIII-section, but no elevated hydraulic conductivity! The HSI-section at 467,5-473 covers this core. Slickensided fractures exists along the whole influence zone but are concentrated on the influence zone above the main core and in the pegmatitic granite unit, at 478-486 m, which is also pervasively illitised.Fracturing has increased slightly around the core section and in the pervasively illitised section. Geophysical anomalies, long normal and short normal, indicate the main core section and altered section, but don't describe the whole influence zone. At the end of the influence zone a change in the foliation direction is seen. The whole influence zone is located on veined gneiss except for the pervasively illitised part, which covers the granitic pegmatitic unit. The upper limit of the zone begins right after the pegmatitic unit and the fracture controlled alteration is interpreted to belong to this pegmatitic unit and is not included into this influence zone. The hydraulic conductivity has been slightly elevated at the pervasively illitised section and at the end of influence zone in fractured part.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR3 470 473 462.5 474 7.5 3.0 1 11.5 The whole influence zone includes short sections of HSI and BJI, increased number of slickensided fractures, pervasive kaolinitisation and fracture controlle illitisation. The main modelled core section is BJI section without any Ri-section. The HSI section at 471-473 m covers it. Both alteration types continue and cover a large area of 430-502 m. However, this influence zone has not been extended to cover the whole area, but more presice part of the core sections and slickensided fractures. The alteration is covered in the alteration model. lGeophysical anomalies are not clear and are probably affected by the large altered area. The upper limit of the influence zone begins right under the pegmatitic unit being totally in a veined gneiss. 491
KR6 124 129 93 144 31 5.0 15 51 The first 10 meters of the large influence zone is located in a pegmatitic granite and rest of it in the mica gneiss. Very short section of tonalitic gneiss is also seen at 115 m. The main modelled core section consists of BFI with RiIII-section and large core loss (3 m). The whole core is hydraulically conductive. A short section of BFI is located above the main modelled core at 117,5-118 m. Also this core is hydraulically conductive. Pervasive illitisation at 117-130 m covers both core sections. Another pervasive illitised part begins from the upper influence zone and continues almost up to the surface. However the upper limit to the influence zone is put vere the slickensided fractures ceases. Same is valid for the lower limit of the influence zone. The main core sections can be seen in the geophysical anomalies, mainly in short normal and long normal, but the whole zone is difficult to define based on geophysics. The main characteristics is the slickensided fractures and alteration.
KR7 690.5 692.02 685 724 5.5 1.5 31.98 39 The main modelled core section consists of BFI and RiIII-V-section also covered by pervasive illitisation between 688-695m. Another BFI section underneath the main core covers HGI section and two RiIII-sections at the both ends of BFI. Yet three more RiIII-sections are located at the influence zone, but they are not mapped as geological core sections. Fracturing has increased in the whole influence zone. Another section of pervasive illitisation at 706-717 m cover two of the three RiIII-sections. Slickensided fractures continue through the whole influence zone. The major part of the zone is located at veined gneiss, but both ends are characterised by pegmatitic granites changing with gneisses.This section at the drill hole has not been measured because drill APPENDIX XI hole was plugged by dropping stones from the drill hole walls. Anyhow, based on drilling information this section is conductive. Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR19 253 261 230 265 23 8.0 4 35 The whole influence zone has clearly elevated fracturing, pervasive alteration and hydraulic conductivity. The main modelled section at 253-260 is BFI and covers two short sections of RiIV-sections at both ends of the BFI. Both RiIV-sections are also hydraulically conductive. A long section of BJI at 238-248 m is also hydrologically conductive and includes slickensided fractures. The pervasive alteration, both illitisation and sulphidisation at 230-260 m, define the major part of the influence zone. The first five meters of the upper influence zone is located on pegmatitic granite and the rest of the zone is on mica gneiss.Hydraulic conductivity has increased along the both core sections. The core sections are also visible as a geophysical anomalies, mainly short normal and long normal, but also in P-wave velocity. Compact influence zone.
KR33 275.5 279 266 305 9.5 3.5 26 39 The main modelled core section consists of BFI section with concentration of slickensided fractures and elevated hydraulic conductivity. Another core underneath the main core at 287-288 m is also hydraulically conductive. Yet another hydraulically conductive section is located at 294 m, but no core exists at the same location. The influence zone is characterised by clearly increased fracturing and slickensided fractures. Geophysical anomalies, long normal and P-wave velocity minimum, describe mainly the area between cores. The main rock type is veined gneiss, but the core sections are located both sides of short pegmatitic unit. Another short pegmatitic unit is at the end of the influence zone. There is no alteration in this section.
KR43 100 101 no data no data no data 1.0 no data no data no data
KR13 450 460 440 498 10 10.0 38 58 The main modelled core section cosists of extremely large BFI section and covers three RiIII-sections and clearly elevated fracturing as well as concentration of slickenside fractures. Also fracture controlled kaolinisation and illitisation are abundant at the core. The main core has somewhat elevated hydraulic conductivity. The
pervasive illitisation continues through the whole influence zone. Another BFI section at 475-481 m is not 492 conductive, but has concentrations of slickensided fractures. At the lower part of the influence zone one RiIII- section has no corresponding geological section, but somewhat increased hydraulic conductivity. Geophysical anomalies, mainly short normal, long normal and P-wave velocity minimum, describe part of the zone. The upper limit for the influence zone begins from the short section of pegmatitic granite, but the main rock type is veined gneiss. The main modelled core section includes also a short section of pegmatitic granite. Also the lower BFI section includes short sections of pegmatite. Finally, the lowest RiIII-sections is located close to the contact of veined gneiss and pegmatitic granite , which covers the rest of the influence zone.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR20 416 429 385 488 31 13.0 59 103 The special characteristics of the influence zone are increased fracturing, slickensided fractures, pervasive illitisation and kaolinisation at 411-430. The main modelled core consists of two long sections of BFI (at 410- 425 m and 427-431 m) and four RiIII-IV -sections. In addition the main core section has elevated hydraulical conductive. The influence zone can be seen in geophysical anomalies, long normal and short normal minimum. The P-wave velocity anomaly shows mainly the core sections. The influence zone can start later, at 410 m, but slickensided fracture at 403 has been connected to this zone because it seems to be connected based on long
normal and short normal anomalies. The slickensided fractures continue further down until the end of the drill APPENDIX XI hole. The upper influence zone begins from the veined gneiss and continues varying between pegmatitic granite and veined gneiss. The lower influence zone is covered by quartz gneiss. The especially large geological core sections are somewhat doubtful, but the influence zone is anyhow quite compact. KR12 581 584 567 590 14 3.0 6 23 The main modelled zone consists of BFI section, which coincides well with RiIII-section with core loss and increased concentration of slickensided fractures. Above the main modelled core hydrological conductivity has been slightly elevated. The upper most RiIII-section, above the main modelled core section, is slightly hydraulically conductive. Another RiIII-section at 590 m has no slickensided fractures and very minor increase in hydraulic conductivity, but is located right at the contact of pegmatitic granite and diatexitic gneiss. The whole zone is covered by pervasive illitisation and fracture controlled kaolinisation. This zone is seen in geophysical anomalis, mainly in short normal and long normal minimum. The zone has not been continued to cover the whole pervasive altered section of drill hole, but only clearly more fractured part. The influence zone begins from the pegmatitic granite, which changes into veined gneiss and back to pegmatitic section. The main modelled core is located on mica gneiss, which in turn changes to pegmatite and further to diatexitic gneiss. Finally the infleunce zone is finnished at the pegmatitic part. The TDS-value increases along the influence zone.
KR5 278 283 249 304 29 5.0 21 55 Influence zone begins right after large TTG-gneiss lickensided. The main modelled coreis BFI section covering the RiIII-section. It is hydraulically conductive and slickensided fractures are concetrated above it. A section (16 m) of pervasively illitisation and fracture controlled kaolinisation at 279-295 m covers the main core section. The upper BFI core is also RiIII-section and has elevated hydraulic conductivity and concentration of slickensided fractures. In addition one HGI section is located at 257-267 m. The elevated hydraulic conductivity is measured right bove it. A special phenomenom is decreasing DS-value along the influence zone. The zone has clearly increased fracturing around the cores. Increased slickensided fractures are concentrated around the cores, but some single one are at the both ends of the zone. The whole zone is clearly seen in long normal and short normal anomalies. The main rock type is veined gneiss, which changes toa short section of granitic pegmatite under the main core section. 493
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR11 623 627 615 650 8 4.0 23 35 The main modelled core consists of BFI section with coinciding RiIII- and RiIV-sections and clear concentration of slickensided fractures and minor elevation in hydraulic conductivity. The fracturing has not increased clearly except around the core, but few concentrations of slickensided fractures exists. This intersection is not altered at all as the rest of the drill hole intersections belonging to this zone. The geophysical anomaly, long normal and short normal minimum, shows clearly the core sections.The main rock type is veined gneiss.
KR29 777 781 775 786 2 4.0 5 11 The main modelled core section consists of RiIV-V sections together with two short sections of fracture controlled illitisation. Water conductive fractures are located at or close by the core. Slickensided fractures don't exists at this intersection. It also looks quite meager compared to other intersections of this zone. Core section can be clearly seen in P-wave velocity anomaly. There are another BFI-core and RiIII-V -section 10 m above this and further another RiIII 15 m above, but these are not included into this zone because rock between these cores is almost fractureless. APPENDIX XI
Averages 16.0 5.2 23.1 44.3
BFZ056 Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR2 24.54 25.75 1.21 Data is missing, no B-borehole exists.
KR10 76.5 77 73 89 3.5 0.5 12 16 Part of the data is missing like hydraulic measurements because of the long casing. There is no clear core section, but fracturing has increased a little and there is few slickensided fractures as well as open fractures along the zone. Fracture alteration, kaolinisation exists between the depth of 75 and 86 meters. At the beginning of the influence zone the diatexitic gneiss changes through short section of pegmatitic granite into veined gneiss. Foliation at the influence zone is somewhat diffuse but the orientation above and underneath is more stable.
KR11 114.2 115.5 104 144 10.2 1.3 28.5 40 Part of the data is missing for this section because of the long casing which ends after the core section and may cause some misinterpretation mainly in hydraulic measurements. There are measurements of quite high hydraulic conductivity right after the casing indicating that casing might leak, however, this is the place for the modelled zone as well so the measured high conductivity might also be natural. The main core is BFI and consists of cruched rock (RiIII-IV). Around the core, in the whole influence zone the fracturing has increased and both slickensided and an open fracture exists. The core section is covered by pervasive illitisation and a section between 136-141 meters is covered by pervasive kaolinisation, which is main reason why influence zone is extended down to 144 instead of 135 where fracturing and especially slickensided fractures cease. The upper limit for the influence zone is based on increased fracturing, which clearly starts at the beginning of the zone. The main rock type is veined gneiss, but two longer pegmatitic units exists. Both long normal and short normal anomalies seem to indicate almost the whole zone. 494
KR12 39.1 40.5 No data No data No data 1.4 No data No data Data is missing, no B-borehole.
KR14 50 51 47.5 56 2.5 1 5 8.5 Short, geologically insignificant section were the measured hydraulic conductivity has increased significantly. Increased fracturing and few slickensided fractures, but no alteration neither clear core section exists. The upper part of the zone is located in the veined gneiss and the lower part in the tonalitic gneiss. Geophysical measurements don't give any clear anomalies at the place of the zone except right at the "core section" where hydraulic conductivity has increased.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR22 144.9 145.6 136.5 162.5 8.4 0.7 16.9 26 Geologically meaningful zone. The main core section, at 145 meters, is represented both as BFI- and RiIII- sections and have elevated hydraulic conductivity. The whole zone is characterised by increased fracturing and existens of slickensided fractures. Also both pervasive sulphidisation and fracture kaolinisation are characteristics for the whole intersection. There are two types of geological cores, BFI at 138-146 and BJI at 149-153. In addition there is altogether three RiIII-sections which coincides with the geological cores. Slickensided fractures have concentrated on core sections but there are still single slickensided fractures all the way through influence zone, as a matter of fact the lower limit for the influence zone is defined based on APPENDIX XI existence of slickensided fractures. The upper limit for the influence zone coincide with alteration and slickensided fracture as well as increased fracturing. The upper limit of the zone is defined quite close to the contact of veined gneiss and diatexitic gneiss, which is the dominant rock type in the rest of the zone. Hydraulic conductivity has increased between 145 and 153, i.e. both lower RiIII-sections are conductive. The whole influence zone can be seen as an anomaly in geophysical measurements, i.e. long-normal, short normal and single point have clearly decreased in the whole influence zone, but the anomalies are lesser at the end of the zone. KR23 195.3 196.1 192.5 207.5 2.8 0.8 11.4 15 Geologically clearly divaricate zone with two core section with elevated hydraulic conductivity. The influence zone is characterised by elevated fracturing around the core. Area between the RiIII-sections is altered consisting of fracture kaolinisation, illitisation and sulphidisation, which does that both cores have been included into the same influence zone. There are two RiIII-sections, but no geological core section. Fracturing has clearly increased around these sections, but there are no slickensided fractures. Hydraulic conductivity has been measured at the RiIII-sections. The long normal and short normal anomaly covers the whole influence zone. Single point and P-wave velocity are describing the increased fracturing. The upper core section coincides with the contact of tonalitic gneiss and veined gneiss. The lower core section is close to the contact of the short section of pegmatitic granite and veined gneiss, but clearly underneath it in the veined gneiss part.
KR24 115.3 115.8 112.5 116.5 2.8 0.5 0.7 4 A short, but clear zone. The high hydraulic conductivity is the main character of this zone. There is one RiIII- section, which seems to be the most conducting place and BJI-section, which covers almost the whole zone. Fracturing has clearly increased at the zone and there are few slicken sided fractures as well. The zone is on the veined gneiss but the lower end consists of pegmatitic granite. The most fractured section is on the veined gneiss, but close to the contact of these two rock types. The zone can be seen in a p-wave velocity anomaly (other geophysical data seems odd, is there a level correction?).
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR25 119 120 112.5 125.5 6.5 1 5.5 13 A very short geologically insignificant section, which have high hydraulic conductivity in two places. Difficult to limit the upper influence zone, but it has been extended to cover the slickensided fracture and the geophysical anomaly. The fracturing has not incresed significantly, but there are few slickensided fractures. Measured 495 hydraulic conductivity is high in two places, at 119 and 124 m. The whole zone is in a diatexitic gneiss. In geophysics long normal and short normal anomalies are present at the hydraulically conductive sections. After the second evaluation the RiIII-section at 114-115 m was included into the influence zone. Probably it is the main core geologically and the the core at 119 m is part of the lower influence zone which is water conductive. Anyhow, the main core has been kept as it was modelled.
KR27 283 283.5 274 296.5 9 0.5 13 22.5 Geologically clearly important divaricate zone. This zone includes four RiIII-sections, two BFI-sections and one large, from 275 to 287 meters, semi-brittle fault intersection. The BFI-intersections include both two RiIII- sections respective. The major part of the zone has clearly increased fracture frequency and there are slickensided fractures, though mainly concentrated on core intersections. This zone is hydraulically conductive and conductivity has concentrated on core sections. From 277 to 285 m the core is pervasively illitised. The rock is less fractured and there are no alteration in the pegmatitic part of the rock from 287 to 292 m. The rock types in the zone, from upper limit to lower, are diatexitic gneiss, mica gneiss, pegmatitic granite and finally diatexitic gneiss again. The rock type might affect (control) certain characteristics of the zone like alteration and fracturing. The second core begins from the contact of pegmatitic granite and diatexitic gneiss. The main part of the zone can be seen in the geophysical anomalies, mainly short normal and long normal. The palce of the main core is difficult to define as well as the influence zone. It could be easily continued downwards, but the vertical zone BFZ053 is interpreted to cover the lower part of this long influence zone down to 347 m.
KR28 172.6 172.7 170 185 2.6 0.1 12.3 15 Clear geological zone located completely in veined gneiss. Main part of the zone around the core has APPENDIX XI increased fracturing and slickensided fractures are abundant. This is the main reason, together with the single water leaking fractures, why the lower limit of the influence zone has been extended down to 185 m, and not cut off earlier. The main core is represented by RiIV-section surrounded by RiIII-sections in both sides and followed by two RiIII-sections deeper down. All these Ri-sections are included into the geological BFI-section between 170 and 177 m. The whole core is hydraulically conductive. Geophysically this zone seems not to be very clear, but can be interpreted to be the latter part of the large anomaly (long normal and short normal), which ceases at the end of this zone, though continuing further up from the upper limit of the influence zone. Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR30 82.5 83.2 80 92.5 2.5 0.7 9.3 12.5 The whole influence zone is completely located in a diatexitic gneiss. Fracturing has increased clearly in the upper part of the zone. The main core is the upper RiIII-section, which is also marked as a BFI-section. Some meters deeper there is another RiIII-section. There are none slickensided fractures in the zone. Both core sections are hydraulically conductive as well as a short section at 92 meters, which is the main reason for the extended influence zone. There are pervasive kaolinisation and fracture illitisation at the core sections. Geophysical anomaly (short normal and long normal) can be seen at the place of the main core section, but P- wave velocity describes the whole zone best.
KR31 174.6 175.4 163 179.5 11.6 0.8 4.1 16.5 The whole influence zone is very clear and it is located completely in diatexitic gneiss. The zone is characterised by slightly increased fracturing and the main core is RiIII-section with short section of core loss, few slickensided fractures and high hydraulic conductivity. There are also another concentration of slickensided fracture at the beginning of the influence zone. The characteristics for the zone is elevated hydraulic conductivity through out the whole influence zone. The whole influence zone can be seen in the P-wave velocity anomalies and the core sections also in long normal, short normal and single point measurements.
KR36 154.7 155.9 152 162.5 2.7 1.2 6.6 10.5 The whole influence zone is located on a diatexitic gneiss. The main core is represented by both RiIV- section and BJI-section. Fracturing has increased clearly at the core section, but otherwise it is low. There are also few single slickensided fractures at the end of the zone. The main core has fracture illitisation and in addition lower down exists two short sections of pervasive sulphidisation. The lower altered section together with slickensided fractures is the reason for the extended lower influence zone. The hydraulic conductivity is concentrated in the upper part of the influence zone, mainly at the core section and the section of the upper pervasive sulphidisation. The main core section is clearly seen in the P-wave velocity anomaly. Additionally both the core and the altered sections are also seen in long normal, short normal and single point anomalies. Underneath this 496 section rock looks really good!
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR37 168 169 167.5 176 0.5 1 7 8.5 This is not a meaningful geological zone, but it has high hydraulic conductivity. It is located at the end of long tonalitic gneiss around the short pegmatitic section. There are very few fractures and only one single slickensided fracture. This section is difficult to detect from the geophysical anomalies. The only characteristics is elevated hydraulic conductivity. Geologically the reason for this zone (place) is probably the existence of pegmatitic granite inside the larger tonalitic unit, at least these coincide well.
KR38 122.22 122.54 112 126 10.22 0.32 3.46 14 The main core section consists of core loss and hydraulic conductivity. A geological BFI-section, one meter downwards, has also slickensided fractures and elevated hydraulic conductivity. The whole zone is located in diatexitic gneiss. Fracturing has increased, especially around the core (core loss) somewhat. There are fracture illitisation between 112,5 and 118 meters. The main characteristic of the zone is elevated hydraulic conductivity along the whole influence zone. The upper part, mainly the altered part, can be clearly seen as a
geophysical anomaly, mainly long normal, short normal and single point anomalies, but the lower influence APPENDIX XI zone as well as the core have no clear geophysical anomaly. KR9 197 198 196.5 228 0.5 1 30 31.5 The modelled main core section, located close to pegmatitic granite and diatexitic gneiss contact, is geologically insignificant with slight increase in fracturing . Most of the zone is located at the diatexitic gneiss except short sections of pegmatitic granite in the beginning of the zone and in the middle of the zone. Fracturing has increased slightly. There is one RiIII-section, which is probably the main core of the zone instead of the modelled one. There are no geological core sections. Slickensided fractures are concentrated on the main core, but few single ones are detected along the whole influence zone. The RiIII-section is altered, both fracture kaolinisation and sulphidisation. There is slightly elevated hydrological conductivity along the whole zone. The whole zone can be seen in geophysical aomalies, SN and LN, and the most fractured part also in single point measurements. The main characteristics for the zone is alteration and hydraulic conductivity through the whole zone. Based on modelled core the influence zone should be very minor, just few meters, but in this case the more probable geological feature underneath has been taken into account in the influence zone.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR40 283.73 284.78 266 287 17.73 1.05 2.22 21 Diatexitic gneiss is the main rock type at the zone, but there is a short section (5 m) of pegmatitic granite at the end of the zone, where also the main core section is located. There are 3 RiIII-section at the zone, but the latest one has been signed as the main core because of hydraulic conductivity, rest of the Ri-sections are not conductive. The Ri-sections also coinside with two sections of fracture illitisation. There are no geological core sections. Fracturing has increased slightly, especially around the cores and there are few single slickensided fractures. In fact the slickensided fractures together with clear geophysical anomaly are the reasons for the extended upper influence zone. The lower influence zone has been extended to include a short section of core loss underneath the main core. There is elevated hydraulic conductivity only at the main core. The whole influence zone can clearly be seen as a geophysical anomaly, long normal, short normal and single point anomalies cover almost the whole zone, however the anomaly decreases towards the end of the zone and is quite insignificant at the main core section! The main characteristic of the zone is the clear geophysical 497 anomaly.
KR42 57.7 58.18 No data
KR4 116.1 116.3 108 117.5 8.1 0.2 1.2 9.5 Geologically very insignificant section, but meaningful hydrological feature. At the main core the hydraulic conductivity is the main feature and it defines the whole zone. Fracturing is very insgnificant and there are no slickensided fractures, but few open fractures concentrated close to HGI-intersection at the depth of 111-112 meters. Long normal anomaly gives some indication of the main core. The influence zone has been limited based on hydraulic conductivity, all other characteristics are insignificant. The influence zone is located at the veined gneiss first two meters and the rest of the zone is in a diatexitic gneiss. The contact between veined and diatexitic gneiss seems to be hydraulically conductive. The section underneath, between 129-164 meters, is altered with fracture kaolinite and sulphides and there is also higher hydraulic conductivity at the depth of 142 meters. This part is not included into any zone because of good rock otherwise.
PH5 57.09 57.2 56 60 1.09 0.11 2.8 4 Data is missing partly. The main characteristic is the high hydraulic conductivity at the marked core section, which in fact is a place for core loss. Fracturing has increased slightly at two places. This zone is located at the diatexitic gneiss, but it's upper limit is at the contact of the larger granitic section (including parts of veined
gneiss). Geologically not significant place but clearly elevated hydraulic conductivity. APPENDIX XI
Averages 5.74 0.79 9.55 16.00
BFZ080 Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR1 176.3 177.4 175 188.5 1.3 1.1 11.1 13.5 The modelled main core section has no Ri- or geological sections. Fracturing has increased somewhat but there is no slickensided fractures at the zone. Between 176-182 m pervasive kaolinisation exists. Hydraulic conductivity has increased between 176 and 188 meters. The whole zone can clearly be seen in long normal and short normal as well as in P-wave velocity anomalies. This zone is minor and the characteristic of it is increased hydraulic conductivity. The rock type is pegmatitic granite and the anomalous part, including core section, of the zone is concentrated on a short section of mica gneiss inside the large pegmatitic granite.
KR2 208.31 208.92 206 275 2.31 0.61 66.08 69 The modelled main core section consists of RiIII-section with core loss and few slickensided fracures. This place does not seem as important as the following core sections between 217 and 225 meters with major increase in fracturing, BFI section and hydraulic conductivity. However both cores belong to a long section of increased fracturing and especially increased amount of slickensided fractures. The lower limit is cut at the depth of 275 m because the slickensided fractures seem to cease there even though they continue at 282,5, but these fractures somehow seem to belong to the place where increased fracturing is concentrated in the upper contact of tonalitic gneiss and has probably something to do with it or belong to another zone. Also in the same place the geophysical anomaly, long normal, arises back at the background level. The whole influence zone consists of seven RiIII-sections and two short sections of core loss. The zone consists of two BFI, one BJI and one HGI sections. Between depths 214-260 m the rock is pervasively kaolinised. The altered part is also hydraulically conductive both at core sections but also around them, highest conductivity being around the depth 236 m. The whole influence zone can be seen as geophysical anomaly in long normal. The major part of the zone is concentrated on the veined gneiss, but the most broken part is where pegmatites and mica gneiss vary in between the veined gneiss.
KR10 326 326.4 318 333 8 0.4 6.6 15 The main modelled core consists of RiIII- and BFI sections and elevated hydraulic conductivity. Around the core 498 the rock has been altered: pervasive illitisation and fracture kaolinisation. The altered part 318-330 is hydraulically conductive, the highest being at the core section. Fracturing has increased some (but not remarkably) and few single slickensided fractures exists. The slight anomaly of long normal and short normal can be seen. The whole zone has concentrated on diatexitic gneiss, but in the middle of the zone right above the core short pegmatitic part exists.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR12 271.87 272.97 254 275 17.87 1.1 2.03 21 The main modelled core section consists of RiIII-section and concentration of slickensided fractures. In addition, another core section is located about 10 m above main modelled one. The whole zone can be seen as a geophysical anomaly in short normal and long normal measurements. The amount of slickensided fractures has increased both at the cores and between them. This is an exceptional intersection for the whole modelled zone, because there is no increased hydraulic conductivity! The lower influence zone is artificially cut, because another broken section between 300-345 probably causes that elevated fracturing continues to the next zone. The zone is mainly located on a diatexitic gneiss, but the last few meters are in tonalitic gneiss.
KR13 189.3 189.8 184 266 5.3 0.5 76.2 82 The main modelled core sections is at 189 m, with slightly increased fracturing and elevated hydraulic conductivity, but no geological core section. This place is close to the contact of above located diatexitic gneiss and veined gneiss. The main geological core is probably at the depth of 216-219. The marked section is SBI APPENDIX XI with RiIII-section and core loss, the highest hydraulic conductivity and the strongest P-wave velocity anomaly in the whole zone. The whole influence zone includes 8 RiIII-sections, one SBI, one BJI and two BFI sections. The most part of itha both fracture kaolinisation and illitisation. The main geological core has the highest hydraulic conductivity. The whole influence zone can be seen in both long normal and short normal anomalies. The fracturing has increased in the major part of the zone and the slickensided fractures are abundant in the whole zone. Very large and significant zone! KR14 217.55 219.13 215 222.5 2.55 1.58 3.37 7.5 The main core is BFI section with a minor increase in fracturing, with few slickensided fractures, minor increase in hydraulic conductivity and long normal and short normal anomaly located mainly above the core section in the upper influence zone. The altered section above is not included into this core because this seems very insignificant place.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR15 201.1 202.44 179 205 22.1 1.34 2.56 26 This main modelled core section consists of only few single fractures and geophysical long normal and short normal anomaly. Very insignificant place! The main characteristics of the zone is strong alteration: around the modelled core, between 196-205 m, pervasive kaolinisation and sulphidisation and between 179-206 m pervasive illitisation and fracture controlled kaolinisation and sulphidisation. The geophysical anomaly describes the zone and based on it the upper limit for the influence zone could be extended to 160 m, but this is not done, because there is no other continuous features. The main rock type is veined gneiss, but a short section of pegmatitic granite occurs between 188-193 m. This zone is not hydraulic conductive!
KR22 423.9 425.3 409 435 14.9 1.4 9.7 26 The main modelled core consists of one BJI section and RiIII-sections with the core loss and elevated hydraulic conductivity. The main core is located at the lithological contact; veined gneiss changes through short section of pegmatitic granite and mafic gneiss to a mica gneiss. About 5 m above the core the rock has both fracture controlled kaolinisation and sulphidisation in about 10 m section. Fracturing has increased, but only one single slickensided fractures exists in the altered section. Hydraulic conductivity has increased at the core and in a short section about 10 m downwards. The influence zone is based on fracturing, alteration, hydraulic conductivity and the clear continuous geophysical anomaly, both long normal and short normal. The geophysical anomaly continues further down including the slightly elevated hydraulic conductivity at 444 m but
it has not been included into the influence zone because there are no other characteristic features continuing. 499
KR24 397 397.9 377.5 401.5 19.5 0.9 3.6 24 The main modelled core consists of RiIII-section and elevated hydraulic conductivity. Ten meters above it is a core loss section and some meters above it over 5 m long section of RiIII. At the same place there is also on single slickensided fracture, but no hydraulic conductivity.The influence zone is located at the mica gneiss and pegmatitic granite. The main core is located at the short section of mafic gneiss and veined gneiss inside the pegmatitic granite. Fracturing has increased only slightly around the core. The geophysical anomaly, acoustic short normal and long normal cover the whole influence zone.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR25 369.9 370.9 363 386.5 6.9 1 15.6 23.5 The main modelled core consists of RiIII-section and clearly elevated hydraulic conductivity. The lower part of the RiIII-section has a short section of core loss. The BJI section covers the depth of 369-373 m including the main modelled core. Hydraulic conductivity is also elevated at the depth of 366 m and slightly elevated at the depth of 386 m. Fracturing has increased around the core section, but only minor increase in the whole influence zone can be seen. Only few single slickensided fractures exists in the whole zone. The whole influence zone is seen as a geophysical anomaly, both short normal and long normal minimum. The whole influence zone is located in a veined gneiss. The lower limit of the influence zone is extended to cover the single hydraulic conductivity at 386 m. APPENDIX XI
KR27 547.38 549.59 537 550 10.38 2.21 0.41 13 This zone is at the final end of the drillhole and the drillhole has probably been finished in the middle of the zone. The main modelled core consists of RiIII-section and increased fracturing around it, but no geological core. Also some slickensided fractures exists. There is no hydrological conductivity measured at this place. The geophysical anomaly, long normal and short normal minimum, covers most of the zone. The upper limit for the influence zone is defined based on single slickensided fracture and the geophysical anomaly which starts at 537 m yet no increased fracturing continues this far up. The whole zone is located at the veined gneiss. KR28 445.4 445.7 442.5 452.5 2.9 0.3 6.8 10 The main modelled core consists of RiIII-section with clearly elevated hydraulic conductivity at the both sides of the core section and increased fracturing and slickensided fractures around the core! Fracturing has only very slightly increased in the influence zone. The geophysical anomaly, long normal and short normal minimum, are describing the whole zone and based on this the lower influence zone could have been extended down to 475 m. The whole influence zone is located at the veined gneiss.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR29 336.5 336.7 302 357 34.5 0.2 20.3 55 Compared to many other intersections of this deformation zone this is clearly significant place. There is two BJI- sections mapped at the same place where the major part of the RiIII-IV sections are located. The modelled main core consists of RiIV-section sourrounded by RiIII-sections at both sides and fracture controlled illitisation. In addition 4 RiIII-section are located close to the main core. The main modelled core has clearly increased hydraulic conductivity. The geophysical anomalies, long normal, short normal and P-wave velocity minimum, cover major part of the zone, but increasing fracturing is the main describing feature for the whole influence zone. Amount of slickensided fractures have also increased, however not so much at the main core, but rather at the both ends of the influence zone. The zone is located close to the lower part of a large mafic gneiss body, following about 20 m section of varying mica gneiss and pegmatitic granite. The main core is located at this varying section. The lower end of the influence zone is again located in the mafic gneiss. TDS-value has increased slightly at the main modelled core section. Influence zone could be also somewhat shorter in both ends, but somehow the included slickensided "areas" are limits to really good, almost fractureless rock around the zone, so they are included into the influence zone.
KR38 383.5 384.8 372 393 11.5 1.3 8.2 21 This is a significant geological intersection as above. The main modelled core consists of RiIV-section with high hydraulic conductivity. The main core is located at the altered section, pervasive illitisation between 382 and 387,5 m. Almost the whole influence zone between 372 and 392,5 m is logged as BJI section. In addition to the main core this influence zone includes one RiV-section at 380 m with surrounding RiIII-section at both sides, 500 another RiIV-section at around 375 m and two additional RiIII-sections. At the depth of 387 m also core loss exists. The whole influence zone is mainly described by increased fracturing but no slickensided fractures exists. Hydraulic conductivity is concentrated on the main core, the upper most RiIV-section an the lower most RiIII-section with core loss. The RiV-sections is not hydraulically conductive. The whole zone, especially the core sections, can be seen at the geophysica anomalies, mainly the long normal minimum, but also in short normal minimum. In addition P-wave velocity minimum seems to describe the zone. The main core is located at the contact of diatexitic gneiss and pegmatitic granite. The whole diatexitic gneiss is covered by the influence zone and the upper most RiIV-section is at the contact between mica gneiss and diatexitic gneiss. About 10 m down from this zone there is another RiIII-section at the contact of pegmatitic granite and veined gneiss (403 m), but it is not included into this zone because there is the 10 m distance between, and the place right at the contact is suspicious. Also geophyical anomalies between this section and the influence zone above are not clearly continuous. A slight increase can be seen in TDS-values measured at the main core section.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR39 178.9 187.5 167.5 192.5 11.4 8.6 5.0 25.0 The main modelled core consists of 3 RiIV-sections, pervasive alteration, both illitisation and sulphidisation, increased fracturing and slickensided fractures at the core. There is no clearly elevated hydraulic conductivity at this section, however, a flow measurement 2/0.25m has some slightly elevated values at the main core. The APPENDIX XI upper influence zone is extended to cover an additional RiIV-section at 168, mainly because the continuous geophysical anomaly consisting of long normal, short normal and single point minimum. Major part of the zone is located on a diatexitic gneis, but the upper core section is at veined gneiss. KR4 370.1 370.6 353 390 17.1 0.5 19.4 37 The main modelled core consists of RiIII-section, elevated hydraulic conductivity and few single slickensided fractures at the upper influence zone. Fracturing has increased slightly around the core. Altered section, pervasive illitisation between 356-360 m, with elevated hydraulic conductivity and slickensided fractures are included into the influence zone, even though it is exatly 10 m from the main core, because it seems to belong to the same geophysical anomaly, i.e. long normal minimum. Also the lower limit of the zone has been extended to include the slightly increased fracturing between 380 and 390 m, because of slightly elevated hydraulic conductivity between this part and the core. There is one single slickensided fracture in this section less than 10 m apart from the slickensided fractures around the main core. The strongly varying long normal anomaly covers the whole influence zone starting already from the beginning of the above zone (BFZ098) at 298 m and continuing down to 440 m. The major part of the zone is located on a mica gneiss but the main core and the largest increase in fracturing is located at or very close to the contacts of small tonalitic gneiss.The lower section of inreased fracturing is at the diatexitic gneiss. The elevated TDS-value from the zone above (BFZ098) decreases back to normal values at the end of this influence zone.
KR40 630.4 631.2 624 638 6.4 0.8 6.8 14 The main modelled core consists of RiIV-section (no geological core mapping done for the cores yet) with clearly increased number of slickensided fractures. The core is located at the contact between the pegmatitic granite and veined gneiss! Fracturing around the core and in the influence zone has increased slightly and there are single slickensided fractures both above and underneath the core section. The upper part of the influence zone is covered by strongly varying long normal and short normal anomaly, which even out at the end of the zone. There is no hydraulic conductivity at the zone.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone
KR7 285.7 287.8 260 310 25.7 2.1 22.2 50 The main modelled core consists of two short BFI sections and three RiIV-sections. Both above and 501 underneath the main core exists one more RiIII-section. The main core is located at the contact between pegmatitic granite and veined gneiss. Especially the upper part of the influence zone, which is located on a pegmatitic granite, has increased fracturing and elevated hydraulic conductivity. The slickensided fractures are concentrared to the lower part of the influence zone at the contact between diatexitic gneiss and mica gneiss, where both fracturing and hydraulic conductivity have increased. The rock type underneath the core is veined gneiss, diatexitic gneiss and mica gneiss. Two altered sections, both fracture controlled sulphidisation, at 265- 275 and 288-301, exists. The whole zone is mainly described by increased hydraulic conductivity, both at the core and around it, though the most part of the altered areas are not conductive! The whole influence zone is covered by geophysical anomaly, bothlong normal and short normal minimum, which continues clearly upwards and also downward. At the lower end of the influence zone there is special feature for the foliation orientation! Very artificial upper limit - could be connected to the zone (BFZ098).
KR8 552.8 555.3 533 570 19.8 2.5 14.7 37 The main modelled core consists of one RiIV- and 2 RiIII-sections. The same area is also covered by BJI section. The main part of the core has been pervasive illitised. Both the core and the influence zone are hydrologically conductive, especial phenomenon is the conductivity in RiIII-sections but none right at the RiIV- section! Clearly increased fracturing is one the main characteristics of this influence zone, but the lower end of the zone has been extended to cover the hydraulically conductive section at 568-570 m. There is only few single slickensided fractures at the core. Based on fracture orientation in a lower hemisphere stereogram, the main dip direction is towards North! Both short normal and long normal anomalies are clear at the whole influence zone and based on these geophysical anomalies as well as P-wave velocity logging the upper limit has been extended to cover this anomaly even though fracturing clearly decreases at 535 m. At 550 m there is APPENDIX XI also some kind of increase in borehole conductivity (EC) and in TDS. The whole section is located under the long section of mica gneiss, which changes through intensive variation of pegmatitic granite, mica gneiss, diatexitic gneiss and quartz gneiss to the long section of pegmatitic granite, and the deformation zone intersection is right at the varying rock type unit. KR9 473.7 474.9 468 503.5 5.7 1.2 28.6 35.5 The main modelled core consists of two RiIII- and one BFI section. Fracturing has increased and there is plenty of slickensided fractures. Almost the whole zone has been pervasive illitised and there is also fracture controlled kaolinite. Hydraulic conductivity has increased in the influence zone and at the upper RiIII-section. The main part of the zone has a clear short normal and long normal anomalies. Both the upper and lower limit for the whole zone is diffuse and quite artificial: it could be combined to the closest influence zone above and just 15 m underneath fracturing increases again with pervasive alteration and plenty of slickensided fractures. However, because there is some kind of "quiet" area between the limit to the lower influence zone and the lower fractured area, it has not been included into this zone. The main core is at the varying rock type contact where mica gneiss changes through pegmatitic granite and diatexitic gneiss to veined gneiss.
KR42 272.83 279.55 No data No data No data 6.72 No data No data No data
Average 12.31 1.48 16.46 30.25
BFZ098 Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone
KR1 142 143 100.0 167.0 42.0 1.0 24.0 67.0 Large influence zone combining two core sections. The main feature is almost continuously elevated 502 hydrological conductivity along the influence zone. The main rock type is veined gneiss, but in the middle of the zone, at the place of the main core, there is pegmatitic granite and short sections of quarts gneiss and mica gneiss. At the place of the second core, at 108-110 m, a short section of mica gneiss is present. The main modelled core consists of BJI and RiIII-section, increased fracturing and hydraulic conductivity. The pervasive illitisation covers the depth of 135-144, i.e. also the main modelled core section. The core section above, at 108-110 m, is included into this zone because of continuous hydraulic conductivity between these two cores. This core consists of BFI and RiIII-section and elevated hydraulic conductivity. Above this core, between 101- 108 m, a section of pervasive kaolinisation and fracture illitisation and sulphidisation is present. Between the cores, at 126-129 m, a short section of fracture kaolinisation and sulphidisation exists. The slickensided fractures exists only sparsely in the whole influence zone, except a concentration close to the upper core, so this is not the defining characteristics for this zone. Based on short normal and long normal measurements the influence zone could be started at least already from 80 m, but for this section the water conductivity has been chosen as a main defining character.
KR10 271.5 271.6 238.0 275.5 33.4 0.1 4.4 37.5 The main rock type along the zone is veined gneiss, but the main modelled core is in mica gneiss and the beginning of the zone is dominated by pegmatitic granite. Large influence zone has been extended to cover the hydraulic conductivity above the main core. The main core consists of BFI and RiIII-sections, but is also covered by longer section 268-276 of HSI. The amount of fracturing doesn't increase significantly in this place except the main core section. Above the main core section, at 261 m, a short RiIV-section together with increased slickensided fractures and elevated hydraulic conductivity exists. The amount of slickensided fractures is increased above the main core, but cease underneath it. The main modelled core is not hydraulically conductive. The influence zone is hydraulically conductive above the upper core at 261 m. Based on long normal and short normal the whole zone could start at 250 and end at 280, but the upper influence APPENDIX XI zone is extended further up because of slightly elevated hydraulic conductivity and the lower one is cut somewhat shorter, because all other characteristics cease. The main characteristics of this influence zone is a minor increase of fracture frequency, hydraulic conductivity at the upper part of the influence zone and increased slickensided fracturing, mainly around core sections, but also some single ones in the upper influence zone. Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR14 183 184 178.5 187.5 4.5 1.0 3.5 9.0 The whole zone is located in a veined gneiss. The main modelled core consists of RiIV-section with short section of core loss and clearly increased hydraulic conductivity, but mapped geological intersection is missing. The minor increase in slickensided fractures exists around the core and the single slickensided fractures exists in the upper influence zone, but none in the lower one. The fracture frequency has not increased significantly except right at the core but some increase can be noticed compared to the rest of the drillhole which is very sparcely fractured. The short normal and long normal show the lower limit for the influence zone, but based on geoophysical anomaly its difficult to define the upper influence zone because it could be continued to further up to the depth of 115 m. The whole section is located on a veined gneiss. Above the zone there is a section of pervasive illitisation, but it has not been included into this zone because fracturing and geophysical anomalies are minor.
KR2 106.7 107.2 94.0 117.0 12.7 0.5 9.8 23.0 The whole zone i located on a veined gneiss except last two meters at the pegmatitic granite. There is no Ri- sections or geological core section at the modelled core, but the concentration of concentration of slickensided fractures exists together with increased hydraulic conductivity. The depth at 98-117 is marked by pervasive kaolinisation and fracture controlled illitisation. At this same section and some meters above, up to 94 m, an increased hydraulic conductivity is characteristic. The fracturing has been slightly increased in the whole influence zone. In long normal and short normal anomalies the whole section can be seen between depths of 95 to 122 m. The last five meters of the anomaly are clearly seen as an anomaly but there is nothing special, except some fractures, is seen in geology so the zone is ended some meters earlier covering the couple of open fractures. The upper influence zone could be continued to the beginning of the drillhole based on continuous increase in fracturing and pervasive alteration. However, it is more possible that it is the influence zone of the closest core section above, at the depth of 45-47 m. Also this depth is still controlled by the surface phenomenon like increase in fracturing and higher hydraulic conductivity.Based on this the limit of the upper influence zoneis set at 106 m. 503
KR22 390.8 391.5 382.5 397.5 8.3 0.7 6.0 15.0 Rock type of the influence zone varies a lot, changing from mica gneiss to diatexitic gneiss to mafic gneiss and then varying between veined and mica gneiss to the end of the zone. There are two RiIII-sections, but no geological core intersection. However a few slickensided fractures close to the modelled core, at 390,8-391,5 m, and clearly increased hydraulic conductivity characterise the modelled core. The section at 385 to 395 has pervasive illitisation and sulphidisation and fracture kaolinisation. Fracturing has increased between 383 and 394. The upper RiIII-section is located at 386-387 close to the main modelled core. The whole zone can be clearly seen in long normal and short normal between 380 and 397. The whole influence zone is mainly described by increased fracturing, pervasive alteration and high hydraulic conductivity at the core. Based on long normal and short normal anomalies the lower influence zone does not continue further even though the single (2) slickensided fractures continue, because they are interpreted to belong to the next core section at 425.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR23 427.6 428.5 420.0 431.0 7.6 0.9 2.5 11.0 The rock type of the zone is veined gneiss.The modelled core section consists of RiIII-section, without geological core section, and clearly increased fracturing and hydraulic conductivity at the core. The upper RiIII- section at 422,5 seems to belong to the same zone with few slickensided fractures around the core, but no APPENDIX XI hydraulic conductivity. No alteration is visible in the whole zone. No long normal or short normal measurements exists. The zone is quite short and sharp. KR24 305 306 294.0 332.5 11.0 1.0 26.5 38.5 The modelled main core section has increased fracturing, slickensided fractures and clearly elevated hydraulic conductivity.The influence zone starts with the diatexitic gneiss and changes through short sections of pegmatitic granite and tonalitic gneiss into veined gneiss and back again to the diatexitic gneiss. Another core section at 330-331,5 has concentration of slickensided fractures around it, short section of increased fracturing and clearly elevated hydraulic conductivity. The slickensided fractures are distinct for the zone but the most significant is the number of sections with high hydraulic conductivity. The short normal and long normal anomalies show mainly the lower RiIII-section. The high hydraulic conductivity is the significant marker of this influence zone, not only in the core but also in the influence zone.
KR25 350.5 350.8 340.0 355.0 10.5 0.3 4.2 15.0 The rock type of the zone is diatexitic gneiss.The core section contains two RiIII-sections, the lower one partly being also RiIV, and one BFI-section. The modelled main core section is the lower one at 350 m. The whole zone is clearly seen as long normal, short normal and P-wave velocity anomaly. Also the fracturing has increased at the zone. The number of slickensided fractures have increased at the modelled main core section and in the lower influence zone. The most significant feature for this whole zone is high hydraulic conductivity both at the core and in the influence zone. Above the influence zone there is a long section with increased fracturing at 310-330. Anyway there is no clear core section and there is also about 10 m "fresh" rock between so it has not been included. This more fractured sections covers the pegmatitic granite sections which might be reason for increased fracturing.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR27 516.8 517.8 505.0 522.5 11.8 1.0 4.7 17.5 The rock type of the whole zone is veined gneiss. There is no clear core section at this place, but the whole 504 zone is described with slightly increasing fracturing, increased number of slickensided fractures and increased hydraulic conductivity. The modelled core section, at 516-517 m, has increased fracturing and concentration of slickensided fractures. The geophysical anomalies, long normal, short normal and single point anomalies, clearly indicate the whole zone except the upper hydrological section. The upper influence zone has been extended to cover the elevated hydrological conductivity and the lower influence zone is extended to cover the single slickensided fracture, because they seem to be characteristic for this zone.
KR28 388 389.8 379.0 395.0 9.0 1.8 5.5 16.0 The rock type of the whole zone is veined gneiss. The main modelled core consists of two RiIV-sections, increased fracturing including slickensided fractures and high hydraulic conductivity. Section between 380-390 m is marked with fracture kaolinisation and sulphidisation. The whole zone is described by long normal and short normal anomalies and especially the main core section also by P-wave velocity anomaly.
KR29 251.5 251.8 240.5 261.0 11.0 0.3 9.2 20.5 The zone starts with the short section of mafic gneiss and then continues as a diatexitic gneiss until end of the zone. The main modelled core consists of short BJI-section, RiIII-section with core loss, high hydraulic conductivity and slickensided fractures around it. The influence zone consists also another RiIII-section with slickensided fractures at 260 m, reason for the extension of the influence zone. Hydraulic conductivity has
mainly concentrated on the main core and few meters underneath it, between 254-256 m. A very minor APPENDIX XI increase in fracturing is visible compared to very fresh rock around this area, but the increase is not significant and has mainly concentrated around the core sections. The short normal and long normal anomalies are covering the upper influence zone clearly, but the limiting factor for the lower one has been the lower core section. Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR38 307.4 308.3 305.0 356.5 2.4 0.9 48.2 51.5 A section of many cores, increased fracturing and hydraulically conductive parts of the rock, which was very difficult to separate into smaller zones, so it has been kept as one large one. The main rock type is diatexitic gneiss, but at the end of the zone, last 5 meters, it changes to pegmatitic granite, which might be the reason for the increased fracturing at the end of zone. The main modelled core, at 307-308 m, consists of BFI and RiIV- sections and elevated hydraulic conductivity. The main core is the uppermost one of seven Ri-sections and the only BFI-section in the zone. Three other ones are BJI-sections. The three upper sections belong to class RiIV and the four lower ones are RiIII. Between 335 and 345 meters. In the upper part of the whole zone it seems like the strain has been more concentrated on three more deformed/crushed RiIV-section while at the lower part of the zone the increased fracturing is more significant phenomenon. Hydraulic conductivity has clearly increased in many places, however concentrated mainly in the core sections. Long normal and short normal anomalies show clear anomaly at the core sections but the whole influence zone is difficult to distinquish based on geophysics. There is another similar type of zone with many cores and hydraulic conductivity at 372-392 m named BFZ080 (R20B) underneath this one. These two are difficult to separate because of somewhat increased fracturing between (360-370) them.
KR39 147 148 114.0 160.0 33.0 1.0 12.0 46.0 Both fracturing and hydraulic conductivity have increased especially in the upper part of the drill hole and it is difficult to draw a limit for the influence zone. The upper part of the zone is located on a pegmatitic granite and the main core section is underneath the contact between the pegmatite and the veined gneiss. There is a short section of mica gneiss close to contact. The main modelled core consists of RiIV-section, core loss section, short section of pervasive illitisation and high hydraulic conductivity. The whole influence zone covers one RiIII- section and two RiIV-sections and core loss at respective place. The fracture frequency is elevated in the whole zone. Between 120 ad 137 m rock is characterised by fracture illitisation and at 115 by fracture kaolinisation (the upper limit for the influence zone is extended to cover it). The whole zone is characterized by elevated hydraulic conductivity. There is few slickensided fractures and some clay-filled fractures. A special feature is the
absence of hydraulic conductivity in the middle part of the altered zone, which is about 10 m wide. The upper 505 hydraulically conductive part of the influence zone is seen in geohpysical anomalies (long normal, short normal and P-wave velocity) as well as the lower part of the zone, but the altered part seems not to be so anomalous. The lower limit to the zone includes the clay-filled fractures, but is then cut where the fracturing almost ceases and the geophysical anomaly ends. However, fracturing increases soon again at 168 m (less than 10 m to the lower limit of this influence zone), but this part has been interpreted to belong to the next influence zone covering the BFZ 080 (R20B). As a conclusion, these two influence zone could be put together to one large one. The upper limit to the influence zone is also quite diffuse and the zone could be continued up to the surface based on continuous increase in fracturing, continuously elevated hydraulic conductivity and anomalous geohysics. Anyway, it has not yet been done, becuase it is interpreted to belong to the surface phenomenom, so the cut off of the upper limit to the inf luence zone is quite artifical. APPENDIX XI Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR4 313.4 314 298.0 325.0 15.4 0.6 11.0 27.0 The rock type is diatexitic gneiss through the whole zone. The main modelled core consists of both RiIII- and BFI sections with clearly increased fracturing and hydraulic conductivity. There is no other cores in this zone. There are single slickensided fractures. The most significant feature is elevated hydraulic conductivity both in the core and in the influence zone. The elevated conductivity has been measured from 298 m to the end of the zone (and continues even further). The upper limit for the influence zone is based on hydraulic conductivity, because increased fracturing at 290-291 m has not been included into the zone while it is interpreted to have to do with the short section of pegmatitic granite between the diatexitic gneiss. The slightly elevated hydraulic conductivity continues down to the next major core which has been named BFZ080 (R20B). The lower limit for the influence zone is very artificial and could be easily continued downwards. The long normal anomaly is describing the whole zone, however this zone seems to belong to the larger area of unstable anomalous part of the rock between 285-442 m. A special issue in this section is the clearly elevated TDS-value measured starting at this section and continuing to the next core at 370, after which it decreases back to normal.
KR40 611.8 611.9 598.0 616.5 13.8 1.1 4.6 18.5 The main modelled core, at 611 m, consists of RiIV-section and elevated hydraulic conductivity. There is also another RiIV-section, at 605-607 m, included into the influence zone also with elevated hydraulic conductivity. Both cores are covered by the pervasive sulphidisation and fracture illitisation between 604 to 616 m. The whole influence zone is characterised with increasing fracturing, increased amount of slickensided fractures, alteration and elevated hydraulic conductivity at the altered part of the zone. Also anomalous short normal and long normal sections start at the beginning of this influence zone, but seems to continue further down covering also the next core section (BFZ080 or R20B). Based on geophysics these two zones could be put together, but at this drill hole they are clearly separated and there is no increased fracturing och hydraulics between the cores. There is again pegmatitic rocks above the whole zone, but this time it is not specially fractured and it is not included into this zone. The rock type of the whole zone is veined gneiss.
KR7 227.1 228.5 191.0 257.5 36.1 1.4 29.0 66.5 Rock types along the zone vary so that all of them are represented, but at least at the beginning the veined 506 gneiss seems the most dominant one and the mica gneiss is the most dominant at the end of the section. Exceptionally large section of mafic gneiss (202-213 m) is in the middle of the zone. The main modelled core consists of RiIV-, BFI and HSI sections with elevated hydraulic conductivity. There is also shorter section of RiIII above the main core. Between 218 and 235 m the drillcore has both fracture kaolinisation and sulphidisation. The main part of the influence zone is described by clearly elevated hydraulic conductivity and increased fracturing, also single slickensided fractures exists. In the upper part of the influence zone there is a short section of pegmatitic granite with increased fracturing together with the short section of fracture kaolinisation. The geophysical log, long normal and short normal, is anomalous mainly between 210 and 240 m and at the end of the influence zone. The lower limit for the influence zone includes the hydraulic conductivity and one single slickensided fracture. This zone could be continued based on continuing fracturing, hydraulic conductivity and long normal and short normal anomalies to include the next main core at 285 m (included into BFZ098 (R20B)). The lower limit of this influence zone is at the moment quite artificial and should probably be modified to be one large influence zone described by significantly elevated water conductivity throughout the whole zone.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR8 452.7 453.1 448.0 455.0 4.7 0.4 1.9 7.0 The rock type along the zone is diatexitic gneiss. The main modelled core consists of BJI and short RiIV- and RiIII-sections and elevated hydraulic conductivity. Hydraulic conductivity has increased also in the beginning of the influence zone. The whole influence zone is characterised by somewhat elevated fracturing, short normal
and long normal anomaly and few single slickensided fractures. Quite short zone! APPENDIX XI
KR9 444.2 445.1 437.0 450.0 7.2 0.9 4.9 13.0 The rock type is diatexitic gneiss. The main modelled core consists of BJI and RiIII-section, clearly increased fracturing and elevated hydraulic conductivity. The whole zone is described by increased fracturing and increased number of slickensided fractures. The core section has a clear geophysical anomaly (long normal, short normal, single point resistivity and P-wave velocity). The hydraulic conductivity is clearly concentrated on the core section and as a special phenomenom the messured TDS-value increases in this core section . For this zone the slickensided fractures are more pronounced than hydraulic conductivity. KR12 144 146 125.0 170.0 19.0 2.0 24.0 45.0 The main rock type is veined gneiss, but there is also pegmatitic granite at 133-143 m and a short section at 153-154 m. The main modelled core section consists of RiIII-section and elevated hydraulic conductivity. In addition, the core section belongs to the HSI section at 144-151 m. This zone is described by increased fracturing, increased amount of slickensided fractures close to core and alteration in the most part of the zone, but only few places with slightly elevated hydraulic conductivity. Another RiIII-section at 128-129 m exists with fracture sulphidisation, but no elevated conductivity. The depth of 133-143 m has pervasive illitisationand 143- 170 m fracture sulphidisation. The whole zone can be seen in geophysical long normal and short normal anomalies. The zone has been extended down to 170 m because of fracture sulphidisation and somewhat increased fracturing. Also the geophysical anomaly supports this. Based on this the lower influence zone is quite large and could probably been cutt off already at 154 m. Alteration is the main characteristic of this zone.
KR15 148.2 148.8 117.5 150.0 52.3 0.4 -20.2 32.5 The whole section is at veined gneiss. The main modelled core section consists of BJI and RiIIV-section and core loss at the same place. Fracturing has increased at the core, but there is no hydraulic conductivity. As a general, fracturing has slightly increased along the influence zone. There is also single slickensided fractures along the zone. The pervasive illitisation and kaolinisation between 136-145 m, and fracture kaolinisation and sulphidisation at 130-136 m are characteristics for this zone. Hydraulic conductivity has been elevated in the upper part of the influence zone, above the main alteration. Geophysical anomaly, long normal, short normal and single point resistivity, end very clearly where the influence zone is defined to be finished, but based on geophysics, the upper influence zone could be extended couple of meters further up.
Description of the zone of influence Hole Upper limit Lower limit Upper limit Lower limit Width of Width of Width of Width of
to core to core to inf.zone to inf.zone upper inf.zone core lower inf.zone whole inf.zone KR16 127.5 130.2 82.5 158.5 69.3 0.8 5.9 76.0 The upper part of the zone is composed of pegmatitic granite, which changes trough short section of tonalitic gneiss to diatexitic gneis and finally at the end of the section to veined gneiss. The main modelled core section consists of long section of BFI (120-135) with slight increase in fracturing and hydraulic conductivity. There is also a clear increase in slickensided fractures at the core section. In addition, two places of core loss exists at 507 the end of the influence zone. The increased fracturing and hydraulic conductivity continues to the surface and has partly been interpreted as a surface phenomenon, so this influence zone could be continued to the surface, but has been limited to the end of the pervasive alteration. The pervasive alteration right above the core consists of illitisation and has also continuously elevated hydraulic conductivity. The geophysical measurements don't react to the pervasive alteration, but the lower part of the influence zone has clearly anomalous long normal, short normal and single point measurements, which continue to the end of the drill hole. Very large influence zone probably because of surface phenomenom, which makes it difficult to define the upper limit for it.
KR17 128.9 129.5 106.0 144.5 22.9 0.6 15.0 38.5 This core section is both geologically and hydrologically significant. In the beginning of the influence zone there is a short section (2 m) of changing rock type from mica to diatexitic to veined gneiss, which then continues further down to the end of the zone. The main modelled core consists of RiIII-section, core loss and BFI section together with elevated hydraulic conductivity. The BFI section covers also another RiIII-section three meters above the main modelled core. The whole BFI section has elevated hydraulic conductivity. In the upper part of the influence zone the alteration is strong, both pervasive kaolinisation and illitisation and in addition also fracture sulphidisation. As mentioned, elevated hydraulic conductivity covers the whole influence zone from 123 m downwards, i.e. from the beginning of the BFI section. The upper influence zone has been extended up to 106 m because of strong alteration, but is limited after the alteration even though elevated hydraulic conductivity continues, because it is interpreted to be the surface phenomenom. Fracturing has increased around the core section, but is in an average level in the upper part of the influence zone, i.e. in the altered part. Slickensided fractures exists in the core sections and continue as a single slickensided fractures even further down. The whole influence zone can be seen in the geophysical anomalies, long normal, short normal APPENDIX XI and single point measurements.
KR42 197.7 198.8 No data No data No data 0.6 No data No data No data
Average 19.9 0.9 10.8 31.4 508 509 APPENDIX XII 510