Master's Thesis

MASTER'S THESIS

Geology of the Salmijärvi Cu-Au deposit

Zimer Sarlus

Master of Science (120 credits) Exploration and Environmental Geosciences

Luleå University of Technology Department of Civil, Environmental and Natural Resources engineering Abstract

The Salmijärvi deposit in northern Norrbotten, Sweden, is a satellite to the giant Aitik deposit and sets 600 m towards the south of Aitik. A recent expansion program in Aitik included the opening of the Salmijärvi mine to meet the increased production demand of 36Mt of ore annually. The new deposit adds 115 Mt of ore to the total resources of Aitik (747 Mt) and expands the mine life with 19 years. This study describes the geology of the Salmijärvi deposit with emphasis on veins, especially mafic veins with a light halo containing abundant ore minerals that are typical of this locality. The information is based on field mapping, drill-core logging, light microscopy, and microprobe analysis. The rocks of Salmijärvi belong to the Porphyrite group and the Kiruna Porphyry group described by Martinsson et al. (1995) and are metamorphosed to amphibolite facies. Several rock units are recognized including amphibole-biotite gneiss, biotite- amphibole gneiss, K feldspar-altered amphibole-biotite gneiss, biotite gneiss, amphibolite, hornblende-banded gneiss, and quartz diorite. The mineralogy is dominated by plagioclase and amphibole with additional biotite, minor quartz and traces of sphene. The deposit is strongly characterized by dark veins composed mainly of magnesio-hornblende making the interior of the veins, and plagioclase forming the surrounding light rims. Ore minerals are chalcopyrite and pyrite containing trace amounts of gold and silver. The ore minerals in the dark veins are generally of larger grain size and surrounded by an oxide rim, while the ore minerals in the matrix have smaller grain size and lack oxide rims. The fluids forming the dark veins has been suggested to be the result of regional metamorphism in addition to the movement of major crustal structure. However, a mafic constituent cannot been excluded. The source of metals in dark veins has not been identified in this study but remobilization of the primary mineralization is suggested as a probable scenario. The Salmijärvi deposit is most likely a product of late stage fluids that either have added or upgraded the Aitik system through remobilization.

Table of contents

1 INTRODUCTION 1

2 REGIONAL GEOLOGY, GEOLOGICAL SETTING AND STRATIGRAPHY OF NORRBOTTEN 3 2.1 METAMORPHISM AND DEFORMATION 7 2.2 MINERALIZATION STYLE AND DEPOSIT TYPES IN NORRBOTTEN 8 2.3 LOCAL GEOLOGY 9

3 METHODS 10

4 GEOLOGY AND PETROGRAPHY OF SALMIJÄRVI 12 4.1 AMPHIBOLE-BIOTITE GNEISS (ABG) 12 4.2 BIOTITE-AMPHIBOLE GNEISS (BAG) 15 4.3 AMPHIBOLE-BIOTITE GNEISS, POTASSIC ALTERED (K-ABG) 15 4.4 BIOTITE GNEISS (BSG) 15 4.5 AMPHIBOLITE (AMPB) 15 4.6 QUARTZ DIORITE (QD) 18 4.7 HORNBLENDE GNEISS OR HB GNEISS (HBG) 19

5 VEINS AND VEINLETS 20 DARK VEINS 20 5.1 HORNBLENDE VEINS WITH A DISTINCT WHITE TO PINKISH HALO (HV1) 20 5.2 HORNBLENDE VEINS WITH NO WHITE HALO (HV2) 20 5.3 HORNBLENDE VEINS AS BLEB/CLUSTER WITH WHITE-PINKISH HALO (HV3) 21 5.4 HORNBLENDE DISCRETE STYLE VEINS (HV4) 21 5.5 PYROXENE VEINS WITH LIGHT HALO (PV) 21 5.6 BIOTITE VEINS (BTV) 21 LIGHT VEINS 23 5.7 ZEOLITE VEINS: (ZV1) 23 5.8 ZEOLITE VEINS: OPEN SPACE FILLINGS (ZV2) 23 5.9 QUARTZ/PLAGIOCLASE VEINS 23 5.10 EARLY QUARTZ VEINS (EQV) 24 5.11 CROSS-STYLE PLAGIOCLASE-QUARTZ VEINS (XPQV) 24 5.12 LATE BARREN QUARTZ VEINS (LBQV) 24 5.13 PLAGIOCLASE QUARTZ VEINS (PQV) 24 5.14 RELATIVE TIMING OF VEIN FORMATION 25 5.15 DARK VEINS 27

6 MINERALIZATION 28

7 GEOCHEMISTRY 32 7.1 MAJOR ELEMENTS 32 7.2 TRACE ELEMENTS 33 7.3 CIPW NORM 33

8 MINERAL CHEMISTRY 38 8.1 AMPHIBOLES 38

8.2 FELDSPARS 39 8.3 ORE MINERALS 40 8.3.1 CHALCOPYRITE (CPY) 40 8.3.2 PYRITE (PY) 41

9 DISCUSSION 44 9.1 MINERALOGY 44 9.2 WHOLE ROCK GEOCHEMISTRY (WR) 44 9.3 MINERAL CHEMISTRY ORIGIN OF DARK VEINS 46 9.4 DARK AND LIGHT VEINS INTERCALATION 48 9.5 ORE MINERALS 50

10 CONCLUSIONS 53

11 RECOMMENDATIONS 54

12 ACKNOWLEDGEMENTS 55

13 REFERENCES 56

14 APPENDIX 1 62

15 APPENDIX 2 64

16 APPENDIX 3 65

17 APPENDIX 4 66

Table of figures

Figure 1.1 A, location of the Salmijärvi deposit within the Fennoscandian shield. B, Salmijärvi and Aitik geology legend. C, Salmijärvi and Aitik geology map. D, interpreted geological profile A-B in Figure 1C, highlighted are the location of drill-cores logged and assayed in this study. Figure 1.1A is modified from Weihed et al. (2005), and Figure 1.1B-D is from Boliden internal reports...... 2

Figure 2.2. General stratigraphy of Northern Norrbotten with main rock units and deformation events (Bergman et al., 2001)...... 7

Figure 2.3 Simplified geological map of northern Norrbotten with major crustal structures. KADZ (Karesuando-Arjeplog deformation zone), NDZ (Nautanen deformation zone), PSZ (Pajala shear zone), KNDZ (Kiruna-Naimakka deformation zone). From Bergman et al., 2001...... 9

Figure 3.1 Map of Salmijärvi deposit and location of open pit samples. The open pit boundaries are represented by thick black lines and ramps by dashed black lines...... 11

Figure 4.1 A, amphibole-biotite gneiss boulder with Hornblende veins type 2. B, amphibole-biotite gneiss groundmass in thin section with two generation of biotite, amphibole completely altered to biotite, K-feldspar altered to sericite and plagioclase also minor titanite. Photo: plane polarized transmitted light. C, potassic altered amphibole-biotite gneiss with epidote showing gneissic texture. D, groundmass mineralogy of biotite-amphibole gneiss Photo: plane polarized transmitted light, E, ore minerals within quartz-plagioclase veins in amphibole- biotite gneiss. Photo: plane polarized, reflected light. F, ore minerals within the groundmass of amphibole-biotite gneiss. Photo: plane polarized, reflected light...... 14

Figure 4.2, A, amphibole clusters within the AMPB. B, hornblende vein type 1 veins curving through ABG and QD rock units. C, paragentic sequence of green minerals within AMPB. D, HBG rock unit with hornblende bands. E, carbonate mineral carrying REEs in amphibole clustesr within AMPB rock unit. F, QD rock unit with chalcopyrite vein, middle left...... 17

Figure 5.1 A, hornblende veins type 1 and hornblende veins type 3 and their typical style of occurrence within the ABG rock unit. B, the hornblende veins type 1 seen in optical microscope with dark interior and distinct lighter halo, plane polarized, transmitted light. C, hornblende veins type 1 with distinct white to pinkish halo. D, hornblende veins type 2 without light halo in K-spar altered ABG rock unit. E, zeolite veins type 1 in two directions with white interior and darker rim of hornblende. F, zeolite veins type 2 occurring in total different fashion compare to zeolite veins type 1...... 22

Figure 5.2. Tentative interpreted paragenetic sequence based on character and style of veins and their relationship observed in outcrops and petrographic microscope...... 25

Figure 5.3 A, crosscutting relationship between hornblende veins type 3, hornblende veins type 1, hornblende veins type 2 and late barren quartz veins in a K-spar amphibole-biotite gneiss. B, a simplified schematic illustration of figure 5.3 A. C, quartz stockwork with early quartz veins crosscut by cross styled quartz veins in QD rock unit. D, cross-styled quartz veins crosscutting hornblende veins type 3 in AMPB rock unit. E, zeolite veins type 1 crosscutting early quartz veins which also show some displacement features and are crosscut by hornblende veins type 1 in ABG rock unit. F, zeolite veins type 1 crosscutting pyroxene veins...... 26

Figure 5.4 Orientation of dark veins in a rose diagram. In total 24 measurements for the dark veins were taken in the field. Dips are ignored...... 27

Figure 6.1 A, chalcopyrite, pyrite and magnetite in matrix of ABG. B, corroded type chalcopyrite overprinted by late euhedral pyrite. C, magnetite in plagioclase quartz veins in HBG. D, magnetite in plagioclase quartz veins in HBG rock unit containing heavy elements such as gold, plane-polarized transmitted light. E, chalcopyrite as free grains in QD matrix. F, large chalcopyrite grain with sphalerite grains along the crack and late euhedral pyrite as inclusion within zeolite veins type 1...... 29

Figure 6.2. Distribution of selected elements across the Salmijärvi rock units. Local coordinates in meters (horizontal scale)...... 30

Figure 6.3. Relationship between copper and gold...... 31

Figure 7.1. Total Alkali versus Silica (TAS) by Cox et al., (1979). The data plot mainly within trachy-Andesite field...... 32

Figure 7.2. Immobile trace elements plotted in classification diagram for volcanics modified by Pearce (1996) after Winchester and Floyd, (1977)...... 33

Figure 7.3. Classic Shand’s diagram (1943) where, three fields (Metaluminous, Peraluminous and Peralkaline) are defined by plotting molecular ratios of major elements against each other. Majority of data plot into the metaluminous field with dispersed pattern stretching toward the peraluminous field. A/CNK=Al2O3 /(CaO + Na2O + K2O), A/NK=Al2O3 /(Na2O + K2O) ...... 34

Figure 7.4. AFM diagram after Kuno (1968) and Irvine and Barager (1971). Majority of data is plotted below the curve dividing the Calc-Alkaline series from the Tholeiitic series...... 35

Figure 7.5. Co-Th plot by Hastie et al., (2007). CA = Calc-alkaline, IAT = Island arc tholeiitic, D/R=Diorite/Rhyolite, H-K = High calk-alkaline, SHO = Shoshanite, BA/A = Basaltic-Andesitic/Andesitic...... 36

Figure 7.6. Ti-Zr discrimination diagram of Pearce (1982) with added data from Salmijärvi, Aitik and surrounding rock units. The yellow and green fields show the extent of Porphyrite and Kirunavaara porphyries group respectively. (Wanhainen et al., 2012 modified from Martinsson and Perdahl (1993, 1995). 37

Figure 8.1 Hornblende classification after Hawthorne (1997). A, hornblende grains within matrix of Salmijärvi rock units, dark veins and zeolite type 1 veins plotting into the magnesiohornblende field. B, hornblende grains of QD matrix plot within the gedrite field...... 38

Figure 8.2 AFM diagram representing hornblende grains analysed in ABG matrix, dark veins and zeolite type 1 veins and QD matrix. All samples apart from the samples of QD matrix plot in a linear trend along the M-F axis. The hornblende samples from QD matrix plot closer to the Alkali (A) corner (red dashed ring). 39

Figure 8.3 Classic feldspars ternary diagram with fields of different plagioclases and potassium rich feldspars. The samples plot in a random fashion within the different fields and show a wide range in composition...... 40

Figure 8.4. Chalcopyrite grains analysed in QD, ABG rock units, hornblende veins (HV) and zeolite type 1 veins (ZV1). The red arrows point out the compositional differences of the trace elements within different type of grains...... 42

Figure 8.5 Pyrite grains analysed in QD and ABG rock units along with hornblende veins (HV) and zeolite type 1 veins (ZV1). The red arrows point out the compositional differences of the trace elements within different type of grains...... 43

Figure 9.1 Diagram showing crystallization time versus vein width contoured for temperature differences. ΔT between country rock and mafic veins (Handy and Streit, 1999)...... 47

Figure 9.2 Diagram showing paragentic sequence of mineral formation, relative age relationship of tectonic, magmatic, metamorphic (shaded area), and mineralization events. Note the timing of the events in red colour (Wanhainen et al., 2012)...... 48

Figure 9.3 A, hornblende veins type 1 displaying parallel reactivation phenomena. B, pyroxene replaced by hornblende at the margins of the pyroxene vein and hornblende at the margins of zeolite vein (top right)...... 49

Figure 9.4. Illustration of remobilization concept modified from Marshal and Gilligan, (1993)...... 51

Figure 9.5 Phase relations in copper-iron-sulphur system at 1000°C, 700°C, 500°C and 300°C. L=Liquid; bnss = bornite solid solution; iss = intermediate solid solution; py = pyrite; po = pyrrhotite; ccp = chalcopyrite; cv = covelite; id= idaite; cc=chalcocite. (Barnes, 1997) ...... 52

1 Introduction

Salmijärvi and Aitik along with Liikavaara and other deposits such as Sorvanen, Nietsajoki etc., are located within the Nautanen field. A man named L Björkqvist after returning back from the United States in 1897 drew attention to this region (Danielson 1987). A year later the Nautanen mining zone was discovered and seven mines were opened. Short after, the incorporated company “Nautanen Kopparfält AB” was started and the town close to the Nautanen hill was rapidly growing with as most 400 residents at the time. Workers strike 1907 lead to termination of the company in 1909. After closure of the company the interest for the area was lost for a few years until P. Geijer in 1917 investigated and geologically described it (Danielson 1987). The history of Aitik and Salmijärvi goes hand in hand and started by the discovery of a chalcopyrite-impregnated boulder in 1930 by Boliden Mineral AB (Zweifel 1976). In 1932, further investigations lead to the discovery of more copper bearing boulders and a small, mineralized outcrop just south of the current mine. Two interesting zones: Aitik and Liikavaara Västra, and Liikavaara Östra (5 km apart), were intersected during the diamond drilling campaign in 1933 to 1936 (Danielson 1987). In outlining the deposit at least ten different geophysical techniques were used over the years (Zweifel 1976). Finally, in 1968, the Aitik mine was opened and put to production by Boliden Mineral AB (Zweifel 1976). The mine produced 2 Mt of ore annually at the initial stage and since then, the production rate has increased dramatically. Salmijärvi is regarded as a satellite deposit to the giant Aitik deposit and sets 600 meters towards south on the same mineralization strike within the southern part of the Norrbotten county (Fig. 1.1). In 2006, an expansion program of Aitik was initiated and in late 2007 geophysical measurements were carried out in Salmijärvi. In the winter of 2010 the first trench was dug and on 21 December 2010 the deposit was test mined. The mine came into full production in 2011 and expanded the mine life of Aitik with 19 years according to the Boliden annual report 2009. Up to date, estimated resources are calculated to 115 Mt of ore and the new open pit will be 1 km long, 800 m wide and 270 m deep when fully mined out. Salmijärvi is very closely related to Aitik but show slightly different characteristics. The deposit clearly lacks an ore-zone defined by lithological rock units such as garnet-bearing biotite schist/gneiss and quartz-muscovite-sericite schist, being the case in Aitik (Wanhainen et al., 2012). Most of the economic ore in Salmijärvi is hosted within the upper portion of amphibole-biotite gneiss (ABG). This rock unit makes the bulk of the footwall and extends towards depth but looses strength in economic minerals. Towards the top it has a sharp contact with barren hornblende-banded gneiss. The ABG is enriched with ore minerals carried within veins and veinlets of intermediate to mafic composition occurring in different shapes and styles. Light and felsic veins are occasionally also enriched with ore minerals.

1 21oE A Geology legend B C Pechenga Quaternary Lapland greenstone Monchegorsk Overburden belt a Tundra Imandra Pana Tundr a Linagranite suit Salmijärvi Pegmatite Portimo Oulanka Haparanda suit Koillismaa Penikat Diorite Skellefte district Raahe-Lado Gabbro

ga z on Burakovo HB gneJss e

Outokumpu Hydrothermal rocks units Tampere Muscovite schist 60oN Biotite schist

Bergslagen Biotite gneJss

Generalized map of the Amphibolite GeneralizedGeneralizedFennoscandian mapmap Shield ofof thethe FennoscandianFennoscandian ShieldShield FSP-EP zone

modifiedmodified fromfrom MapMap ofof thethe Porphyry group FennoscandianFennoscandian ShieldShield scalescale 1:21:2 millionmillion KoistinenKoistinen etet al.al. (2001)(2001) Amphibole-biotite gneJss

00 250250 500 kmkkmm

D A B A B

These veins and veinlets are also present in the footwall of Aitik but are not equally enriched with ore minerals, thus not much attention have been paid on them so far. The objective of this study is to (1) describe the geology (rock types, mineralogy and alteration) of the Salmijärvi deposit. (2) Describe the different style of veins and veinlets and the ore minerals carried within them, and ultimately work out their paragentic sequence and chronological order. Finally, the objective (3) is to correlate the findings into a regional geological context. Acronyms used in this study are summarized in table 1 below.

Table 1. Acronyms used in this study.

Acronyms ABG Amphibole-Biotite gneiss BAG Biotite-Amphibole gneiss K-ABG K-feldspar-amphibole-biotite gneiss AMPB Amphibolite QD Quartz diorite HV Hornblende vein ZV Zeolite vein PV Pyroxene vein PQV Plagioclase-Quartz vein XPQV Crossed- or X-style Plagioclase-Quartz vein BTV Biotite vein EQV Early Quartz vein XQV Crossed-styled Quartz vein

2 2 Regional geology, geological setting and stratigraphy of Norrbotten

The geology of Norrbotten is a product of a complex geodynamic evolution affected by several geological events including macro and micro-continental collision, subduction processes, rifting and associated sub-events that formed the shape of the modern Fennoscandian Shield that occupies northern Europe extending from Norway in west to Russia in east (Weihed et al., 2005). In general, three major geological units constitute the Fennoscandian Shield: the Archaean Basement (>3.0-2.5 Ga), Palaeoproterozoic sedimentary and mafic to intermediate meta-volcanic rocks (2.44- 1.96 Ga), and the Svecofennian (1.96-1.85 Ga) meta-sedimentary and meta-volcanic rocks placed on top of old supracrustal rocks of Palaeoproterozoic age (Fig. 2.1). These rocks host various type of deposits including VMS, IOCG, Ni-Cu-PGE, epithermal lode gold, iron apatite, stratifrom-stratabound base metal, and epigenetic copper gold etc. Short summaries of the rocks belonging to each period mentioned above are presented below together with the tectonic events that played a major role in their formation. The prime aim of the description is to give a general overview of the main rock types found in northern Norrbotten, and the rest of the Fennoscandian Shield is thus not discussed. The oldest rocks found in the Fennoscandian shield are the nuclei’s of the Karelian and Kola cratons that were fragmented and reassembled during the Palaeoproterozoic (Weihed et al., 2005). The Karelian craton was subdivided into Belomorian mobile belt and three complexes: Central Karelian, Lisalmi and Pudasjärvi. Rocks of the central Karelian are dated to 3.05 Ga (Sm-Nd method, Slabunov et al., 2006). However, the oldest rocks of the Karelian craton are found within the central part of the Pudasjärvi complex dated to 3.50 Ga (Lobach- Zhuchenko et al., 1993; Mutanen and Huhma, 2003). Archaean rocks in Norrbotten are mostly found north of Kiruna. These rocks are dominated by deformed granitoids (Ödman, 1957; Öhlander et al., 1987; Martinsson et al., 1999). The composition is mainly tonalitic to granodioritic. These Archaean rocks are younger than those found in the Karelian and Kola cratons. From studies of tonalites, an emplacement age of 2.83 Ga and a metamorphic crystallization age of 2.7 Ga is suggested by Skiöld (1979) and Martinsson et al., (1999). A low content of Ta, Nb, Y, and Th in these rocks is indicative of a destructive plate margin environment of formation. This suggests that the tonalites were formed in a primitive, probably an oceanic arc, setting, while the granodiorites originate from a mature arc setting (Martinsson 2004). Less abundant red granitic intrusions with an age of 2.7 Ga are the youngest rocks from Archaean found in Norrbotten (Skiöld and Page, 1998; Ödman, 1975; Offerberg, 1967). During the period 2.5 – 1.9 Ga several periods of magmatism, denudation and sedimentation took place due to repeated continental rifting events. Hotspot activity is the suggested explanation for the repeated rifting events indicated by intrusion of

3 21oE

Inari BMS Norr- Kola craton botten BMB craton

PC Skellefte CKC

Knaften acarc Savo ac TKS

Umeå IC Karelian craton

Caledonian orogenic belt Keitele Bothnia 60oN Uusimaa Sveconorwegian Bergslagen Orogen

Generalized map of the SvecobaltiaSvecobaltica Fennoscandian Shield Gothian Orogen modified from Map of the Fennoscandian Shield scale 1:2 million Koistinen et al. (2001)

0 250 500 km

Archaean Palaeoproterozoic Igneous rocks and gneiss (3.20_2.50 Ga) Supracrustal rocks (2.50_1.96 Ga) _ Supracrustal rocks (3.20 2.75 Ga) Mafic intrusive rocks (2.50_1.96 Ga) Mesoproterozoic Granulite belt (>1.90 Ga) Rapakivi granite association (1.65_1.47 Ga) Supracrustal rocks (1.96_1.84 Ga) Sedimetary rocks (1.50_1.27 Ga) Igneous rocks (1.96_1.84 Ga) Phanerozoic Granite and migmatite (1.85_1.75 Ga) Caledonian orogenic belt (0.51_0.40 Ga) Igneous rocks, TIB1 (1.85_1.76 Ga) Alkaline intrusions Igneous rocks, TIB2 (1.71_1.66 Ga) Phanerozoic sedimentary rocks Neoproterozoic Sveconorwegian orogenic belt (1.10_ 0.92 Ga), partly reworked Paleo- to Mesoproterozoic rocks

! Figure 2.1 Geological map of the Fennoscandian shield including Kola, Karelian and Norrbotten cratons. Abbreviations: BMB=Belomorian Mobile Belt, CKC=Central Karelian Complex, IC=Iisalmi Complex, PC=Pudasjärvi Complex, TKS=Tipasjärvi–Kuhmo–Suomussalmi greenstone complex. BMS=Bothnian Megashear (Koistinen, 2001).

4 numerous layered mafic igneous complexes (Alapieti and Lahtinen, 2002; Amelin et al., 1995). The intrusions were later deformed and metamorphosed during the Svecokarelian orogeny (1.9 – 1.8 Ga). This episode of events lead to formation of graben structures infilled with poorly sorted clastic sedimentary rocks comprising conglomerates overlained by epiclastics, quartzite, mica schist and carbonate rocks. As the depositional basin became deeper, fine-grained sediments, phyllites and carbonaceous sulphide-bearing black schists were deposited on top (Lehtonen et al., 1998; Hanski et al., 2001; Vaasjoki, 2001). Mafic sills with a zircon age of ca. 2.2 Ga (Skiöld et al., 1988) intruded the lower part of the sequence thus giving a minimum depositional age for this group. The supracrustal rocks mentioned above are collectively named as the Kovo Group defined by Martinsson (1997). These rocks uncomfortably overlay the Archaean basement in the Kiruna area, together with a sequence of tholeiitic meta-basalts and calc-alkaline meta-volcaniclastic rocks. Overlaying the Kovo Group is a 2-4 km thick pile of mafic to ultramafic volcaniclastic rocks defined as the Kiruna greenstone group by Martinsson (1997). The main rock types are meta-basalts, commonly graphite-bearing meta-argillite, crystalline carbonate rock, and ultramafic rocks with minor komatiite, tholeiitic tuff and andesitic to dacitic tuffaceous rocks. Based on petrographical and geochemical properties the Kiruna greenstone group is divided into six subgroups given local names to the different suits found in several areas (Martinsson, 1997). The Svecofennian or Svecokarelian (both names occur in literature) orogeny gave rise to the most intense crustal growth in Palaeoproterozoic at 1.90 – 1.80 Ga. The period was characterized by several accretionary units at three collisional stages at 1.91 to 1.90, 1.89 to 1.88, and 1.86 to 1.84 Ga according to the model presented by Lahtinen (1994). Rocks in the Knaften area (1.95 Ga) south of the Skellefteå district in Sweden and primitive island arc rocks of the Savo Belt (1.92 Ga) in Finland are the oldest documented Svecofennian units in the Fennoscandian Shield (Fig. 2.1) (Korsman et al., 1997; Wasström, 1993). In the Norrbotten and Kiruna area, Svecofennian rocks stratigraphically overlay the Kiruna greenstones. The lowest sequence of the Svecofennian unit comprises old meta-sedimentary rocks consisting of various clastic sequences and locally found calc-silicate (skarn) and rare carbonate rocks. In the Kiruna area the Palaeoproterozoic Greenstone group is overlain by meta-conglomerate (Kurravaara conglomerate) and meta-sandstone (Martinsson and Perdahl, 1993). Higher up in the stratigraphy the Svecofennian meta-volcanic rocks are placed (Fig. 2.2). These meta-volcanic rocks are divided into two groups, the Porphyrite and overlying Porphyry group, originally named by Offerberg (1967) and later reworked and studied by Martinsson and Perdahl (1993, 1995). The Porphyrite group consists of metamorphosed low-titanium andesites, basalts and minor intercalations of felsic tuff and tuffites. Martinsson and Perdahl (1995) suggested that these rocks were formed in a compressional environment based on a high content of alkalis, which is an attribute of anomalous crust rather than enrichment through differentiation. The Porphyry group consists of metamorphosed basalt, trachy-andesite and rhyodacite-rhyolite. Generally, a high-titanium content and zirconium distinguishes the Porphyry group from the underlying Porphyrite group, however both groups show very similar petro-physical properties (Bergman et al., 2001). Younger supracrustal rocks of clastic meta-sedimentary origin atop the meta-volcanic rocks of the Porphyry group. They consist of red meta-sandstone, meta-conglomerate, meta-arkose and quartzite. These rocks are well persevered and 5 show primary structures formed in a continental or near shore environment (Witschard and Zachrisson, 1995a).

Intrusive rocks

The geology of Norrbotten is strongly characterized by different suits of intrusive igneous rocks, in particular suits ranging in age from 1.90 to 1.71 Ga. The oldest plutonic rocks are referred to as the Haparanda suit and are found in the southeastern, northern Norrbotten and northern Finland (Ödman et al., 1949). These rocks range from gabbro to granite in composition but are mostly dominated by diorite- granodiorite. These rocks can be described as greyish in colour, equigranular, and deformed. Their origin is believed to belong to early Svecofennian arc magmatism with an age of ca. 1.90 to 1.88 Ga (Bergman et al., 2001). The Perthite Monzonite suite is dominated by monzonite with varying amounts of gabbro, monzo-gabbro, monzo-diorite, quartz-monzonite, and granite. Characteristic for this suit of rocks are the compositional zoning from a felsic center to more intermediate and mafic outer parts (Kathol and Martinsson, 1999). These intrusions are common in the northwestern part of Norrbotten but rare in the eastern part of the region (Geijer, 1931; Witschard, 1984). A mantle plume origin is suggested for these rocks (Martinsson, 1997). The Perthite Monzonite suite is generally undeformed although magmatic foliation may occur at the contacts. There are at least two generations of intrusive rocks known to belong to the Transscandinavian Igneous Belt (TIB), which mostly occur in the northwestern part of Norrbotten. The TIB is a giant array of large massifs of granitoids rocks and associated mafic intrusions stretching from the southeastern most part of Sweden to the northwestern part of Norway, ranging in age between 1.85 to 1.67 Ga. The TIB event is suggested to have taken place due to eastward subduction (Weihed et al., 2002) possibly during a period of extensional conditions (Åhäll and Larson, 2000). In general, these rocks show different characteristics from subduction related late Palaeoproterozoic to Mesoproterozoic plutonic rocks such as TTG-type (trondhjemite-granodiorite) in Scandinavia. The composition vary from monzonitic or syenitic to quartz monzonitic and granitic (Romer and Wright, 1992; Romer et al., 1994). Many of them have the character of ring dikes with a diameter of 3 to 7 km and locally form concentric composite intrusions with mafic to intermediate phases (Lindroos and Henkel, 1981). The Lina granite covers large areas in northern Norrbotten and show limited compositional variation from granite to pegmatite and aplite. The emplacement age has been determined to 1.79 – 1.78 Ga (Skiöld et al., 1988; Bergman et al., 2001). Variations do exist. This is demonstrated by different generations of intrusives and pegmatites. Tectonically the Lina-type granite is regarded as typical minimum melt granites created by crustal melting. Several theories for the heat source are presented, where a collision event further to the south is suggested by Öhlander and Skiöld (1994) or simultaneous TIB magmatism by Åhäll and Larson (2000). The Lina granite is commonly greyish red, medium-grained and weakly porphyritic. Also other varieties occur described as red, fine-grained and equigranular (Geijer, 1931). The content of mafic minerals are low with biotite being the common phase and muscovite the rare one.

Caledonian nappes

Sedimentary cover Major unconformity Gp Younger meta- Gsg Gabbro, dolerite, metagabbro (Gd) sedimentary rocks Granite-pegmatite ass. (Gp) Granite-syenitoid-gabbroid ass. (Gsg) Minor unconformity Gd

Porphyry group and Older metasedimentary G Granitoids, c. 1.86–1.84 Ga (G) rocks

Pms Perthite monzonite suite (Pms) SVECOFENNIAN

Porphyrite group and Hs Haparanda suite (Hs) Older metasedimentary rocks

Minor unconformity

Greenstone group M Mafic sills and dykes (M) KARELIAN

Kovo Group

Major unconformity

M Ultramafic-mafic intrusions

M Late Archaean granite ARCHAEAN

Granitoid rocks, gneisses Metasupracrustal rocks

= Deformation and metamorphism

Figure 2.2. General stratigraphy of Northern Norrbotten with main rock units and deformation events (Bergman et al., 2001).

2.1 Metamorphism and Deformation Studying the degree of deformation of the Haparanda and Perthite Monzonite suite, Bergman et al., (2001) suggested an event of regional metamorphism and deformation at 1.88 Ga. A second deformation event took place at 1.81 to 1.78 Ga recorded by chronological data from zircons and monazite in the Pajala area (Bergman and Skiöld, 1998). The regional metamorphic pattern varies from high in

7 the east to low in the west. Archaean rocks generally display high-grade metamorphism, but medium-grade metamorphic rocks also exist. Proterozoic high- grade metamorphic rocks are found in the east and south-central parts. The metamorphic grade varies from upper greenschist facies to lower amphibolite facies in Northern Norrbotten. Granulite facies rocks are rare. Characteristic index minerals in pelitic precursors are andalusite and sillimanite (Bergman et al., 2001).

2.2 Mineralization style and deposit types in Norrbotten Northern Norrbotten is an ore district characterized by copper and iron deposits, including several ‘unusual types‘, and regional as well as ore related hydrothermal alteration is dominated by scapolitization and strong alkali metasomatism (Martinsson et al., 1995). Apatite iron ores, with more than 40 known occurrences in northern Norrbotten, are found generally within the Porphyry or Porphyrite group of Svecofennian rocks. However, host rock lithology, host rock relations, host rock alteration, the phosphorous content and associated minor component content may vary from deposit to deposit. These deposits are economically regarded as the most important and produces more than 31 Mt of high-grade ore annually mostly from the famous Kiirunavaara and Malmberget mines (Martinsson, 2004). In addition to the apatite iron ores, the most important metallic deposits have been divided into stratiform-stratabound base metal deposits and epigenetic sulphide deposits. Majority of the base metal deposits are dominated by copper but in some prospects lead and zinc are the dominant commodities. Stratiform base metal and sulphide deposits occur mostly within the volcaniclastic units of Palaeoproterozoic greenstones associated with graphite schists and carbonate rocks (Martinsson, 2004). The only economic stratiform deposit so far in northern Norrbotten is the Viscaria deposit located immediately to the northeast of Kiruna town. Epigenetic copper gold deposits are another group of important deposits in northern Norrbotten, specifically in areas around Kiruna and Gällivare. Several of these types of deposits have been mined during 17th and 18th century. Few important discoveries in later years were the Nautanen and Pahtavaare deposits. However, a far more important discovery was the Aitik deposit in early 1930s with current reserves and resources estimated close to 1000 Mt. The epigenetic copper gold deposits are hosted generally within the highly deformed Svecofennian volcano sedimentary rocks of 1.9 Ga. These deposits are often spatially related to major crustal structures.

8 2.3 Local geology Salmijärvi along with the Aitik deposit is situated within Svecofennian volcano- sedimentary rocks (1.9 Ga) stretching some 40 km in length and having an average width of 5 km, surrounded by younger Lina granite, migmatite and gabbro (Zweifel, 1976; Monro, 1988). The trend of the zone is N20W. These volcano-metasediments belong to the Porphyrite group (Wanhainen and Martinsson, 1999). The volcano- metasediments are folded into a syncline in the eastern part and form an anticline to the west. The Salmijärvi and Aitik deposits are located in the western limb of the anticline. Both of these deposits are trapped between two large regional ductile shear zones. To the east, the Nautanen deformation zone (NDZ) is running in a NNW-SSE direction over a distance of ca. 1500 km and can be traced from lake Lagoda in Russia to the Kiruna District in Sweden (Monro, 1988) (Fig. 2.3). From s-c fabrics in a mylonitised granodiorite east of Gällivare a southwestern-side-up movement for the zone is suggested. Many Cu-Au occurrences are spatially related to the NDZ (Martinsson and Wanhainen, 2004). To the west the Karesuando-Arjeplog deformation zone is found comprised of several ductile to brittle shear zones with an approximate width of 8 km, and s-c fabrics indicate western-side up movement to dextral movement (Bergman et al., 2001). Both of these major deformation zones were active at ca. 1.8 Ga. The bedrock in the area are deformed and metamorphosed to upper amphibolite facies.

Proterozoic metamorphic Allochthonous rocks supracrustal and intrusive (Caledonian orogen) rocks: Sedimentary cover Low-grade (Vendian–Cambrian)

Medium-grade PAC950581 3.8/715 Ductile shear zone High-grade Råsto- Proterozoic intrusive rocks, jaure Naimakka Sample number unmetamorphosed or only 50 km P/T deterPLQDWLRQ NEDUÝ& locally metamorphosed (<1.88 Ga) Archaean rocks (> c. 2.68 Ga) Z

KN Karesuando

PAC961021A STB971001 2.6/615 3.5/665 KADZ

Övre Lannavaara Rensjön Soppero Muonionalusta

Kebnekaise Kiruna PAC940026D Lainio 3.6/570

STB971108 Vittangi 4.0/630 Svappavaara STB951052 6.2/690

Fjällåsen Kä98:4-2 Huuki STB940051 Masugnsbyn 2.6/510 7.5/805 Stora Sjöfallet NDZ A

KADZ STB951021C 4.1/515 Pajala

Malmberget Tärendö A A PSZ Gällivare Figure 2.3 Simplified geological map of northern Norrbotten with major crustal structures. KADZ (Karesuando-Arjeplog deformation zone), NDZ (Nautanen deformation zone), PSZ (Pajala shear zone), KNDZ (Kiruna-Naimakka deformation zone). From Bergman et al., 2001.

9 3 Methods

Samples for petrographic studies and whole rock (WR) lithogeochemical analysis were collected from diamond drill cores and outcrops from the open pit of Salmijärvi in late summer of 2012. In total 1300 meters of core from 4 drill- holes along a profile (Fig. 1.1d) were logged and 24 samples for petrographic analysis and 8 for WR analysis were selected. Parts of the open pit were also mapped and 4 samples (Sal 001-004) for petrographic analysis and 13 samples (Sal 1029-1042) for WR analysis were collected from outcrops (Fig. 3.1). Samples for petrographic analysis were sent to Vancouver Petrographics LTD in Canada for thin section preparation. Samples for whole rock analysis were collected from homogeneous, representative drill core sections of at least 70 cm length and a minimum of 1 kg from the outcrops. All samples were analysed for major elements, trace elements and gold in ALS chemex laboratories, Canada. Major elements were analysed by inductively coupled plasma atomic emission spectrometry (ICP-AES). Trace elements were analysed by inductively coupled plasma mass spectrometry (ICP-MS). Base metals were analysed by four acids, ICP-MS. Gold was analysed by fire assay fusion and ICP-AES and volatiles by aqua regia ICP-MS. Nine thin sections (Sal 002, 1007, 1008,1011,1012,1018,1021,1022,1028) were analysed by EPMA (Electron probe micro-analyser) at Uppsala University in order to confirm the mineralogy observed within the petrographic microscope. In total 24 structural measurements were taken for dark veins and 5 for foliation within the rock units. The locations of all samples collected from the open pit are shown in Figure. 3.1.

L 14

L 15

L 4.1

L с>ŽĐĂƟŽŶ/Ě = Sampled points Scale 1:5000 (cm)

Figure 3.1 Map of Salmijärvi deposit and location of open pit samples. The open pit boundaries are represented by thick black lines and ramps by dashed black lines.

11 4 Geology and petrography of Salmijärvi

Rock units within the Salmijärvi deposit exhibit similar textures and characters as those in the Aitik deposit, described in detail by Wanhainen et al. (2012) and Wanhainen et al. (2003). However, a few rock units present in Aitik are absent within the Salmijärvi deposit and those present in Salmijärvi are: amphibole-biotite gneiss (ABG), biotite-amphibole gneiss (BAG), potassic altered amphibole-biotite gneiss (K-ABG), biotite schist/gneiss (BSG), amphibolite (AMPB) and quartz-monzodiorite (QD) making the main footwall (FW) rocks. The hanging wall (HW) is mainly comprised of hornblende-banded gneiss. Late pegmatite dykes cross cutting several of these rock units are also present. The economic mineralization is held mainly within footwall rocks. The hanging wall is considered uneconomic. All rock units are characterized by vein and veinlets of various compositions and intensity. Each rock unit is described in detail below.

Footwall rocks

4.1 Amphibole-Biotite Gneiss (ABG) The ABG is a green to dark green-grey rock with an average grain size of 2 mm exhibiting an aphanitic texture. The groundmass mainly comprises plagioclase and biotite with additional amphibole, K-feldspar and minor amounts of titanite (sphene) and opaque phases. The opaque phases are pyrite, chalcopyrite and oxides, with the dominant oxide being magnetite. Traces of molybdenite are also observed. Biotite grains in the groundmass occur lathlike elongated, irregularly oriented and partly altered to chlorite. Biotite also occurs in biotite veins and within hornblende veins. At least two generations of biotite are present. The early generation is also partly altered to chlorite and perpendicularly overprinted by a more fresh looking second generation (Fig. 4.1b). The content of biotite varies as much as several percent within the rock unit. It is almost absent, or present in minor amounts, when the rock is strongly sericite altered. Plagioclase is the dominant feldspar phase making the bulk of the rock unit. Several generations are present. The oldest generation is reflected by biotite and quartz grains replacing the primary plagioclase phase, indicating pre- metamorphic origin. Semi-altered grains with inclusions of sericite represent another generation of plagioclase. A late generation of plagioclase occurring as veins with much larger grain size is also observed. Few grains of K-feldspar are present, containing inclusions of biotite, and being associated with chlorite and quartz. Amphibole occurs as irregularly acicular shaped grains partly replaced by chlorite and in some cases completely replaced by biotite giving it a pale brownish colour (Fig. 4.1b). As with biotite, the content of amphibole varies within the matrix. However, it is the main component of the dark veins and is mostly associated with opaque phases.

12 The opaque phases comprise mainly of pyrite, chalcopyrite, pyrrhotite, magnetite and ilmenite (Fig. 4.1e and Fig. 4.1f). They occur as dissemination in the ground mass and as a component of the dark veins throughout the mineralized part of the rock unit. Minor and trace amounts of pyrrhotite, molybdenite, ilmenite and rutile are occasionally related with the main ore mineral phases. The structure of this rock type is strongly defined by dark veins composed mainly of hornblende occurring as stockwork, open spaced and discrete veins. There are also multiple generations of quartz-plagioclase veins present but the frequency is much lower than the hornblende veins, see section 5. In general, this rock type has experienced multiple alteration events, where some parts are strongly leached, silicified, sericitized and potassic altered giving it a white-grey to pale pinkish appearance. Also chlorite, biotite, and epidote alteration phases in minor proportions are observed. A meter section with 2-5 mm large crystals (porphyroblasts) of garnet are observed as dense clusters mostly associated with epidote occurrence. Late meter-wide barren pegmatite dikes are observed as well.

13 a b Bt Hbl

Kfs Hbl

Bt Qz Amp Ttn Pl 200 um

c d Ser

AAmpmp

Pl Ttn

2 cm

Titanite 250 um

e f

c p

200 um 50 um

Figure 4.1 A, amphibole-biotite gneiss boulder with Hornblende veins type 2. B, amphibole-biotite gneiss groundmass in thin section with two generation of biotite, amphibole completely altered to biotite, K-feldspar altered to sericite and plagioclase also minor titanite. Photo: plane polarized transmitted light. C, potassic altered amphibole-biotite gneiss with epidote showing gneissic texture. D, groundmass mineralogy of biotite-amphibole gneiss Photo: plane polarized transmitted light, E, ore minerals within quartz-plagioclase veins in amphibole-biotite gneiss. Photo: plane polarized, reflected light. F, ore minerals within the groundmass of amphibole-biotite gneiss. Photo: plane polarized, reflected light.

14 4.2 Biotite-amphibole gneiss (BAG) This rock unit exhibit the same mineralogy as the ABG rock unit except that the content of amphibole is much higher (Fig. 4.1d). Two generations of plagioclase can be distinguished: one altered, containing inclusions of amphibole and sericite, and one fairly fresh. Both generations have roughly the same size 100-200 um. Epidote as an alteration product within the amphibole veins is fairly common. The matrix contains a slight amount of disseminated pyrite and chalcopyrite grains with fairly small grain size of 35 μm and 30 μm, respectively. The most common veins are the dark veins occurring within rock sections carrying larger grains of pyrite and chalcopyrite with a tight rim of magnetite.

4.3 Amphibole-biotite gneiss, potassic altered (K-ABG) This rock type is strongly potassic altered giving it a grey-pinkish to dark greenish colour characterized by gneissic banding (Fig. 4.1c). The groundmass is mainly composed of plagioclase, amphibole, and titanite with minor amounts of quartz and biotite. An early sericite alteration of the primary plagioclase is overprinted by a late potassic assemblage. Epidote and chlorite are also present as results of amphibole breakdown within the hornblende veins. The rock unit is strongly dominated by dark veins, however light veins are also present. The intensity of dark veins increases towards the contact with amphibole-biotite gneiss. The contact is gradational. In places this rock unit is heavily mineralized with chalcopyrite, pyrite, magnetite and pyrrhotite mostly bound to the dark veins. The ore minerals also occur in the groundmass as dissemination.

4.4 Biotite gneiss (BSG) This rock unit has a grey colour, is fine to medium grained and composed mainly of plagioclase, biotite (partly altered to chlorite), amphibole and rare quartz with accessory titanite. Epidote, scapolite, K-feldspar and sericite are the alteration phases within this rock unit. Traces of scheelite are present as well. Opaque phases are dominated by pyrite, chalcopyrite and magnetite. Chalcopyrite occur as disseminated grains together with pyrite in the matrix. Chalcopyrite and pyrite with a surrounding rim of magnetite is characteristic for opaque phases carried within the dark veins (Fig. 4.1e).

4.5 Amphibolite (AMPB) The amphibolite has a grey-dark green colour. It can be described as a fine- grained rock with 1-5 mm rounded amphibole clusters giving the rock a porphyritic texture (Fig. 4.2a). These phenocrysts contain inclusions of a carbonate mineral containing REEs (Fig. 4.2e). The amphibolite has by Boliden geologists been interpreted to be situated within amphibole-biotite gneiss of the footwall as a rounded body and at the boundary between amphibole-biotite gneiss and hornblende banded gneiss in the hanging wall as a sheet-like body (Fig. 1.1d).

15 The groundmass comprises mainly plagioclase, K-feldspar partly altered to sericite, and elongated biotite grains. Amphibole occurs as irregular crystal phases partly altered to chlorite and biotite. Quartz is present in minor amount. Sericite within grains of plagioclase and feldspar are present with rare epidote grains in the matrix. The large amphibole clusters contain irregular shaped amphibole crystals clearly overprinting the groundmass minerals. The clusters contain opaque phases composed mainly of magnetite. Biotite is common as inclusions with a grain size of 100 μm. The rock unit contains mostly magnetite as disseminated grains within the matrix and within veins of mainly quartz and plagioclase. The magnetite, which is 40–200 μm in size, is also associated mainly with the green minerals. Chalcopyrite and pyrite occur as small grains (25 μm and 50 μm, respectively) disseminated within the matrix. In this rock unit the dark veins referred as hornblende type 3 veins dominate closely followed by cross style quartz veins. However, hornblende type 1 and hornblende type 2 veins are also rather common and minor late barren quartz veins occur as well. The contact with the amphibole-biotite gneiss is gradational.

16 a b

Amp HV1 Bt Bt ABG QD

Opaque phases

250 Um

c d Pl Bt

Amp Ep

Bt Kfs

Bt 250 Um 2 cm

e f

20 um

2 cm

Figure 4.2, A, amphibole clusters within the AMPB. B, hornblende vein type 1 veins curving through ABG and QD rock units. C, paragentic sequence of green minerals within AMPB. D, HBG rock unit with hornblende bands. E, carbonate mineral carrying REEs in amphibole clusters within AMPB rock unit. F, QD rock unit with chalcopyrite vein, middle left.

17 4.6 Quartz Diorite (QD) The quartz diorite has a white-greyish colour with darker patches composed mainly of quartz, K-feldspar, plagioclase and biotite with accessory amphibole associated with the opaque phases. The quartz grains are euhedral with equant shape and an average grain size of 200 μm. Biotite within the matrix has an average grain size of 100 μm and is overprinted and crosscut by a later generation of biotite that is 1-3 mm in grain size and aligned in a N-S foliation direction. The younger biotite generation gives the rock a porphyritic to gneissic mottled character (Fig. 4.2f). K-feldspar grains have a rounded shape, are partly altered to sericite, and contain inclusions of biotite laths. In few cases plagioclase overgrow and replaces K-feldspar grains. Plagioclase that is partly replaced by biotite is the dominant mineral phase within the rock unit. Amphibole is present as potassium and titanium rich gedrite within this rock unit. Titanite as dispersed grains is present in minor proportions. The contact to amphibole-biotite gneiss is sharp, (Fig. 4.2b) and the quartz diorite occurs as xenoliths within the amphibole-biotite gneiss. This rock type crops out in the south-eastern part of the Aitik deposit as well and is described in more detail by Wanhainen et al. (2006). The ore minerals occur as disseminated patches within the groundmass and as a component of light and dark veins. The ore mineral assemblage comprises mainly pyrite, chalcopyrite and magnetite. At least two types of chalcopyrite are present. The first type is anhedral and has a fresher look occurring in the groundmass with no oxide rims The second type has a corroded appearance surrounded by a tight rim of oxides often associated with the amphiboles (Fig. 6.1). This rock unit is in places strongly affected by early quartz veins; cross style quartz veins and zeolite type 1 veins, however dark veins are present as well.

18 Table 2. Main matrix mineralogy of Salmijärvi rock units based on visual estimation from thin- sections, examined in petrographic microscope.

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Hanging wall rocks

4.7 Hornblende gneiss or HB gneiss (HBG) The HBG has a light grey greenish colour, a fine grain size, and is characterized by late veins composed mainly of amphibole in the foliation direction giving it a gneissic texture (Fig. 6.1). Plagioclase, K-feldspar (both partly altered to sericite), biotite, and quartz in minor amounts are the main minerals in the groundmass with accessory tourmaline and titanite. An alteration assemblage consisting of sericite, epidote, and chlorite is present. Strong sericite altered sections and late quartz veins are also characteristic of the rock unit. A chronological sequence of the green minerals can, based on the examination of thin-sections in the petrographic microscope, be seen in the matrix of the hornblende gneiss (Fig. 4.2). Early biotite is overprinted by light green hornblende, which is cut by a darker green amphibole and in turn crosscut by a later generation of biotite. The opaque phases within this rock unit is dominated by magnetite occurring as dissemination and veins showing enrichment close to the latest biotite vein sequence mentioned above. The magnetite contains traces of heavy elements such as e.g. Au, Ag, and Pb. (See section 6). Chalcopyrite rarely occurs as disseminated grains within the matrix.

19 5 Veins and Veinlets

In this section the most common veins and veinlets that characterize the Salmijärvi rock units are presented and described. These veins occur in different styles, from tree-like structures, blebs-clusters, slightly folded to straight arrow shaped, and have different intensity within the different rock units. The most common veins are grouped based on the composition similarity.

Dark veins A network of dark veins with a pronounced white to pinkish halo dominates the texture of the footwall amphibole-biotite gneiss. These veins are also present within other rock units of the Salmijärvi deposit including the quartz-diorite but with lower frequency. These veins show pre-syn and post-metamorphic characteristics. At least five different styles of dark veins are observed and described below.

5.1 Hornblende veins with a distinct white to pinkish halo (HV1) These veins propagate in the foliation direction with arrows branching out almost oblique to perpendicular from the main stream suggesting syn- or late to post-metamorphic conditions (Fig. 5.1a). The center of the veins comprises mainly hornblende with sporadic biotite grains towards the rims. Chlorite and solitary secondary quartz grains are also present in some cases. Titanite is strongly associated with some of these types of veins. The outer part occurring as a light rim around the darker center comprises mainly plagioclase and K-feldspar, both occasionally altered to sericite giving a white to pinkish brownish colour (Fig. 5.1c). Minor quartz grains and rare biotite laths are also present within this white to pinkish halo. In general, hornblende veins type 1 are 1-2 cm wide and heavily mineralized and carry ore mineral assemblages dominated by pyrite, chalcopyrite, magnetite with minor pyrrhotite, and traces of other sulphides as well. Characteristic for the ore minerals within these veins are that in most cases the sulphides are rimmed by oxides, mainly magnetite (Fig. 4.1e).

5.2 Hornblende veins with no white halo (HV2) These hornblende veins are also abundant within the footwall amphibole- biotite gneiss but appear with minor intensity in other rock units as well. These veins lack the typical white to pinkish halo surrounding the hornblende veins type 1 (Fig. 5.1d). These veins propagate as well within the foliation direction and can be over meters long but much thinner, ranging in width between 1-5 mm. The main component within these veins is magnesio-hornblende giving it a dark appearance. This style of veins carry opaque phases mostly concentrated

20 towards the center of the veins. Opaque phases comprise pyrite, chalcopyrite and magnetite. They also show a late stage to post metamorphic characteristics.

5.3 Hornblende veins as bleb/cluster with white-pinkish halo (HV3) These veins lack the distinct sequence of a dark inner core and a light outer rim as previously described hornblende veins type 1 and hornblende veins type 2. The minerals of the darker parts and the minerals of the lighter parts rather intercalate as the veins propagate through the rock unit (Fig. 5.1a). These veins range from a centimeter to a decimeter in size. The darker parts are composed mainly of hornblende partly altered to chlorite, and slightly folded biotite laths indicating syn to post-metamorphic conditions. Larger crystals of biotite partly altered to chlorite are also present. The lighter parts are composed of plagioclase (partly altered to sericite) and solitary quartz grains. In addition to plagioclase and quartz the lighter parts contain cassiterite (Fig. 4.2e). These veins are also mineralized with pyrite and chalcopyrite as main ore constituents but these ore mineral grains are lacking the oxide rim around the grains making them significantly different from hornblende veins type 1, hornblende veins type 2 and hornblende veins type 4. .

5.4 Hornblende discrete style veins (HV4) These veins often have a teardrop shape with a core of hornblende with minor amounts of epidote. The white halo comprises mainly plagioclase and quartz. Biotite laths and titanite grains are also present in minor amounts. These veins are folded in several directions suggesting an early or pre-metamorphic origin

5.5 Pyroxene veins with light halo (PV) Large euhedral to subhedral pyroxene grains constitute the darker interior of the vein containing inclusions of titanite, plagioclase, K-feldspar and biotite. Smaller hornblende grains are restricted to the outer part of the dark interior replacing the pyroxene. The light white to pinkish halo is composed of plagioclase and quartz with minor K-feldspar (Fig. 5.3f and Fig. 9.3).

5.6 Biotite veins (BTV) These veins are very thin, as most 2 mm wide, consisting mainly of biotite laths oriented randomly. The biotite veins are barren and do not carry ore minerals.

21 a b HV vein, the white halo

HV vein inner part

c d

2 cm 2 cm

e f

22 Light veins Felsic veins composed of light-coloured minerals are grouped and described below. Zeolite veins Two different styles of veins with white interior and dark rims are observed and described below.

5.7 Zeolite Veins: (ZV1) These veins are very common in most rock units, but dominates in the amphibole-biotite gneiss of the footwall and has a light interior and dark rims propagating through the rocks as long arrows slightly deformed to undeformed in two main directions (Fig. 5.1e). Different minerals such as zeolite, plagioclase (partly altered to sericite) and minor quartz grains occupy the center of the vein while hornblende is restricted to the outer part forming the darker rim. Few grains of pyroxene as inclusions within the zeolite grains are observed in the core of the veins. A thin line of sericite running along the outer part of the dark hornblende rim at the contact with matrix completes the vein sequence from inside out. These veins range in size from 5-10 mm and carry opaque phases, mainly small pyrite and magnetite grains as inclusions within much larger chalcopyrite grains. Also small sphalerite grains as inclusions within the chalcopyrite are observed (Fig. 6.1f).

5.8 Zeolite veins: open space fillings (ZV2) These veins have the same composition as the zeolite veins type 1 with zeolites making up the center part and amphibole (mainly hornblende) making up the outer darker rims, with sericite forming the lighter halo around the veins. The significant difference between zeolite veins type 2 and zeolite veins type 1 is the shape and style of occurrence. The zeolite veins type 1 reach lengths of several meters but the width is limited to 5-10 mm, while the zeolite veins type 2 are only up to a decimeter long and commonly wider than 5 cm. The zeolite veins type 1 are deformed and in places heavily mineralized (Fig. 5.1f).

5.9 Quartz/Plagioclase veins Several different styles of light veins and veinlets mainly composed of quartz and plagioclase are present within the different rock units of the deposit. These veins are abundant within the quartz diorite but also observed to a minor extent in other rock units. Some of these veins are rich in sulphides and some are barren. Few are discussed below.

23 Quartz stockwork The quartz stockwork is mainly composed of two vein sets, early quartz veins and cross-style plagioclase-quartz veins.

5.10 Early quartz veins (EQV) These veins are approximately 1 cm thick and show displacement features. They constitute the thicker part of the quartz stockwork (Fig. 5.3c and e).

5.11 Cross-style Plagioclase-Quartz veins (XPQV) These veins are a combination of two vein sets where the younger generation crosscuts the older one. Most abundant minerals within the vein-sets are plagioclase accompanied by minor amounts of quartz (Fig. 5.3c and d). The main difference between the older and younger generation is the magnetite content being far more abundant within the younger generation, which also contains some biotite laths. The size of these veins range between 1-4 mm (Fig. 5.3d). These veins carry ore minerals, mainly pyrite and chalcopyrite.

5.12 Late barren quartz veins (LBQV) Late quartz veins, 1-2 mm wide and undeformed to slightly deformed, crosscut most of the dark hornblende veins and zeolite veins. These quartz veins are barren and do not carry economic minerals (Fig. 5.3a).

5.13 Plagioclase quartz veins (PQV) These are very thin (< mm) veins composed mainly of plagioclase with minor quartz occurring in the center of hornblende veins (bands) of HBG rock unit of the hanging wall. These veins are placed in the foliation direction and contain magnetite.

24 5.14 Relative timing of vein formation The relationship between these different type of veins and veinlets are closely studied within the outcrops and sub-crops of the Salmijärvi open pit. Obvious crosscutting relationships between these veins and veinlets are easily observed in macro scale at the outcrops and complemented by observations from the petrographic microscope. An attempt to place these veins on a time line based on crosscutting relationships, and their character and degree of metamorphism are presented in Figure. 5.2.

EARLY RELATIVE TIME LATE

Veins Pre-metamorphic Syn-metamorphic Post-metamorphic

Hornblende Veins type 1

Hornblende Veins type 2

Hornblende Veins type 3

Hornblende Veins type 4

Pyroxene veins

Biotite veins

Zeolite veins type 1

Zeolite veins type 2

Early quartz veins

Late quartz veins

Cross type quartz veins

Plagioclase quartz veins

Figure 5.2. Tentative interpreted paragenetic sequence based on character and style of veins and their relationship observed in outcrops and petrographic microscope.

The oldest veins are the hornblende veins type 3 which are crosscut by hornblende veins type 1 in perpendicularly to oblique fashion. The hornblende vein type 1 are crosscut by hornblende vein type 2, which are crosscut by a late sequence of late barren quartz veins (Fig. 5.3a). A simplified illustration of this relationship is shown in Figure. 5.3b. Cross styled quartz veins are crosscutting the hornblende vein type 3 and are crosscut by zeolite veins type 1, as shown in Figure. 5.3c and d. Zeolite type 1 veins are younger than hornblende veins type 1, pyroxene veins, and quartz stockwork as demonstrated by Figure. 5.3c and f. Cross styled quartz veins are crosscutting the thin biotite veins, and plagioclase- quartz veins are younger than the hornblende veins type 1 as observed in the petrographic microscope.

a b HV2 HV1

K-SPAR ALTERED ABG HV3 HV3 LQV HV3 LQV HV2

HV2 HV1 VEINLET CHRONOLOGY HV3 EARLY HV1 HV2

HV1 LQV LATE LQV

c QD ROCK UNIT d

XQP

EQV XQP HV3

AMPB ROCK UNIT

2 cm

e ABG ROCK UNIT f

ZV1

EQV 1 cm

26 Orientation of veins and structures

5.15 Dark veins During field mapping, the orientation of a limited number of dark veins were measured. The results are presented in a rose diagram (Fig. 5.4) to get a general overview of their distribution. The results indicate two dominant directions: NW-SE and NE-SW. These veins usually crosscut each other and form “X” or cross-styled veining. It has not been possible to predict the chronological sequence between these two vein sets with methods used in this study.

Figure 5.4 Orientation of dark veins in a rose diagram. In total 24 measurements for the dark veins were taken in the field. Dips are ignored.

27 6 Mineralization

The economic mineralization is mainly hosted within ABG, BAG, K-ABG, AMPB, BSG and QD rock units dipping approximately 60° to the west. The HBG unit of the hanging wall is almost barren and not considered economic. The main ore mineral is chalcopyrite accompanied by an opaque mineral assemblage of pyrite, pyrrhotite, magnetite and ilmenite with traces of sphalerite and gold. Silver, nickel, cobalt, antimony, bismuth and tin are elements occurring in trace amounts and carried within the chalcopyrite and pyrite grains. Ore minerals occur disseminated, as clusters and patches within the matrix of the rock units and within the hornblende, plagioclase, quartz and zeolite veins. The latter style of mineralization is quantitatively the most important and in places highly enriched. The amount of ore minerals is generally high close to the hanging wall and pinches out towards depth. Chalcopyrite and pyrite within the groundmass of ABG and QD, and within the hornblende veins and zeolite veins show distinctive variation in chemical composition. At least six chalcopyrite and five pyrite types can be distinguished. (See section 8 Mineral chemistry for details). One general observation is that chalcopyrite and pyrite within most veins are rimmed with oxides, while sulphides within the groundmass commonly lack this oxide rim and are usually much more fine-grained. Gold occasionally occur within the structure of certain types of chalcopyrite and pyrite (See section 8.3 for more details). However, the correlation between copper and gold as presented in Figure 6.3 indicates that gold unrelated to copper also exists. Magnetite occurs as rims around vein sulphides and as disseminated grains throughout the deposit, mainly in association with sulphides and titanite. It is most abundant within HBG and AMPB rock units, where it is commonly carried within the plagioclase quartz veins (Fig. 6.1c). Magnetite within the HBG rock unit exhibits a lamellae texture with dark and creamy white bands. The darker parts contain traces of As, Bi, Cu, Ag, Zn and gold while the light creamy parts contain Pb, Zn and gold but lack As, Bi, Cu and Ag (Fig. 6.1d). The distribution of selected elements such as gold, Cu, Zn, S, and Fe across the main rock units in Salmijärvi are illustrated in Figure. 6.2. The noticeable difference is the high content of Zn and Fe within the HBG rock unit of the hanging wall. Gold and copper show a similar pattern with higher values within ABG and QD rock units.

28 a b

50 Um 50 Um

c d

250 Um 50 Um

e f

ccp

ccp Sphalerite

100 Um 200 Um

Figure 6.2. Distribution of selected elements across the Salmijärvi rock units. Local coordinates in meters (horizontal scale).

30 !"#)*#("#

!#&$"

!#&"

!#%$"

*+"-"+"

!"#$%%&'# !#%" /01234"5*+"-".+6"

!#!$"

!" !" %!!!" &!!!" '!!!" (!!!" $!!!" )!!!" ("#$%%&'#

Figure 6.3. Relationship between copper and gold.

31 7 Geochemistry

In order to classify rock units and put those into a regional geological context a series of diagrams and plots are used based on WR (Whole rock) data collected from logged drill-cores and open pit samples. Results from the WR analysis are summarized in appendix 1.

7.1 Major elements Rock units of the Salmijärvi deposit has experienced several deformation events and is metamorphosed up to amphibolite facies and show strong potassic alteration in places. This is very important to keep in mind when using the TAS (Total Alkali vs. Silica) classification diagram of Cox et al. (1979) (Fig. 7.1), as major elements can be very mobile thus less reliable. The majority of data plot into the trachy-andesite field however exhibiting two distinct groups. The larger group plots close to the gabbro to syeno-diorite field, and the minor group (Sal 006, 1029, 1031, 1036, 1037, 1039,1040) plots close to the Quartz-diorite (granodiorite) field.

Ultrabasic Basic Intermediate Acid 15 Alkaline

Nepheline syenite

Syenite

10 Syenite O 2 K

Syeno Trachy Granite

O Andesite

2 diorite a N Ijolite Quartz Gabbro diorite ABG (granodiorite) 5 HBG Diorite AMPB Gabbro BAG K-Spar ABG

Subalkaline/Tholeiitic QD 0 40 50 60 70 SiO2

Figure 7.1. Total Alkali versus Silica (TAS) by Cox et al., (1979). The data plot mainly within trachy- Andesite field.

32 7.2 Trace elements Trace elements are more suitable to use for classification purposes since these elements are less sensitive for enrichment or depletion during hydrothermal alteration thus stay chemically immobile. The classification diagram of Pearce (1996) after Winchester and Floyd (1977) is currently the most widely diagram used as a proxy to the TAS diagram of Cox et al., (1979). The majority of data plot into the andesitic/basaltic-andesitic field, with exception of samples, sal 1029 and sal 1037 that plot into the rhyolite-dacite and trachy-andesite field, respectively (Fig. 7.2).

Nb Y Zr TiplotmodifiedbyPearce1996

alkali rhyolite

0.500 phonolite

rhyolite trachyte dacite

tephriphonolite trachy T i andesite 0.050 Z r andesite, basaltic andesite ABG alkali foidite basalt HBG AMPB 5

0.005 BAG basalt K-Spar ABG QD 0.001 0.01 0.10 1.00 10.00

Nb Y

Figure 7.2. Immobile trace elements plotted in classification diagram for volcanics modified by Pearce (1996) after Winchester and Floyd, (1977).

7.3 CIPW norm From CIPW norm calculations (Table 3), using the geochemical toolkit of Janousék (2006), the formation of normative corundum within few samples indicate gain of aluminium as an effect of potassic alteration, pushing the affected samples toward the peraluminous field (Fig. 7.3). However, the majority of the samples are dominated by formation of normative anorthite and hypersthene suggesting alumina under-saturation or metaluminous conditions. The alumina deficiency is accommodated in hornblende, titanite and Al-poor biotite. The normative quartz, with silica enriched relative to alkalis, indicate subalkaline rocks further subdivided into calc-alkaline and tholeiitic series.

33 A/CNK A/NK plot (Shand 1943) 7

6 Metaluminous Peraluminous 5 4 A/NK 3 2 1

Peralkaline 0 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 A/CNK

Table 3 Results from CIPW norm calculation using the geochemical toolkit of Janousék (2006).

!"#$%&'() *+,(-)%." Q C Or Ab An Di Hy Ol Il Hm Tn Ru Ap Pr Sum HBG !"#$%&%' 4.499 0.000 7.446 34.778 22.169 7.300 9.867 0.00 0.383 10.700 1.764 0.000 0.497 0.019 99.42 HBG !"#$%&%( 9.740 0.000 17.197 31.985 21.915 7.608 1.455 0.00 0.340 7.310 1.230 0.000 0.379 0.019 99.18 HBG !"#$%&') 28.523 0.000 12.942 24.031 21.030 0.339 5.024 0.00 0.190 6.750 0.319 0.000 0.166 0.019 99.33 AMPB !"#$%&%* 15.995 0.000 25.707 11.593 24.933 5.687 4.786 0.00 0.597 7.850 0.972 0.000 0.403 0.019 98.54 AMPB !"#$%&%+ 6.278 0.263 23.580 30.801 16.590 0.000 8.543 0.00 0.000 9.610 0.000 0.730 0.568 0.220 97.18 AMPB !"#$%&'% 2.997 0.000 11.878 37.062 17.787 5.141 8.950 0.00 0.205 12.900 2.092 0.000 0.711 0.075 99.80 AMPB !"#$%&(, 2.201 0.000 5.496 46.455 20.769 9.924 7.505 0.00 0.361 5.460 1.423 0.000 0.947 0.019 100.56 ABG !"#$%&&* 3.789 0.000 18.202 39.093 14.914 0.000 11.532 0.00 0.000 8.080 0.020 0.992 0.734 0.220 97.58 ABG !"#$%&&+ 17.565 0.622 26.948 28.008 12.269 0.000 4.060 0.00 0.000 6.970 0.000 0.490 0.426 0.169 97.53 ABG !"#$%&'+ 3.377 0.000 12.588 32.578 21.858 5.737 7.677 0.00 0.000 11.300 2.799 0.000 0.734 0.254 98.90 ABG !"#$%&(% 12.928 0.371 24.762 32.070 18.987 0.000 4.160 0.00 0.000 4.460 0.000 0.500 0.545 0.186 98.97 ABG !"#$%&(' 0.000 0.000 18.793 32.070 17.525 9.846 5.460 0.69 0.483 10.500 1.266 0.000 0.640 0.075 97.35 ABG !"#$%&(( 3.810 0.000 21.748 24.708 17.498 18.772 1.834 0.00 0.859 9.960 0.486 0.000 0.545 0.150 100.37 ABG !"#$%&(+ 19.520 0.561 21.334 29.362 12.341 0.000 4.259 0.00 0.000 9.350 0.000 0.430 0.616 0.220 97.99 ABG !"#$%&(- 12.585 0.740 30.258 31.816 8.273 0.000 5.305 0.00 0.000 6.500 0.000 0.480 0.616 0.271 96.84 ABG !"#$%&(. 1.147 0.000 24.466 30.124 17.360 7.854 5.376 0.00 0.000 9.210 1.718 0.000 0.640 0.355 98.25 ABG !"#$%&() 15.292 0.000 18.675 30.801 16.348 2.415 5.904 0.00 0.000 6.900 1.326 0.000 0.450 0.220 98.33 ABG !"#$%&,% 7.291 0.000 14.774 39.432 18.357 0.563 4.945 0.00 0.000 8.680 1.743 0.000 0.640 0.237 96.66 BAG !"#$%&(& 0.975 0.000 9.928 43.916 18.537 2.874 8.357 0.00 0.027 11.000 2.297 0.000 0.616 0.131 98.66 BAG !"#$%&(* 2.967 0.000 20.920 32.070 17.554 6.410 5.721 0.00 0.442 10.250 0.901 0.000 0.853 0.056 98.14 QD !"#$%&,& 15.926 0.000 17.847 34.185 14.829 6.885 1.541 0.00 0.000 5.710 1.203 0.000 0.403 0.406 98.94

34 For further subdivision of subalkaline rocks, the AFM diagram (Fig. 7.4) after Kuno (1968) and Irvin and Baragar (1971) is used. Generally, weight percent (wt%) oxides are used when plotting the data. Using a Trivariate plotting procedure such as AFM diagram may limit the petrogenetic information extracted. In most cases the AFM parameters make up less than 50% of the oxides weight parentages and therefore cannot fully represent the rock chemistry. Keeping this in mind, AFM diagrams have to be interpreted with caution. Most of the samples cluster within the calc-alkaline field but do follow the trend line of tholeiitic series.

Tholeiite Series

Calc alkaline Series

A M

Figure 7.4. AFM diagram after Kuno (1968) and Irvine and Barager (1971). Majority of data is plotted below the curve dividing the Calc-Alkaline series from the Tholeiitic series.

The Co-Th plot by Hastie (2007) acts as a proxy for the K2O-SiO2 diagram by Peccerillo and Taylor (1976) for classifying rock units found within volcanic arc settings. This diagram works well with rocks that have undergone hydrothermal alteration or metamorphism. Usually Co (Cobalt) stays immobile within mafic metamorphic phases such as amphiboles and chlorites. Most of the samples plot within the BA/A (Basaltic-Andesite and Andesite) field. They also cluster in the high K calc-alkaline field but dominantly within the shoshonite field (Fig. 7.5).

35 Co Th plot (Hastie et al. 2007)

H K and SHO 10.00 h

T CA 1.00

ABG HBG IAT 0.10 AMPB BAG K-Spar ABG B BA/A D/R* QD 0.01 70 60 50 40 30 20 10 0 Co

The Ti vs Zr discrimination diagram of Pearce (1982) is mainly constructed for volcanic rocks but is equally suitable for comparison between different rock types. Data for volcanic rocks belonging to the Porphyrite group (light green area) and Kirunavaara porphyries group (light yellow area) and Aitik host and surrounding rocks are added for comparison with rocks of Salmijärvi. Majority of samples from the footwall and hanging wall of Salmijärvi together with data from Aitik plot within the Porphyrite group. However a small increasing pattern can be observed where samples mainly from the AMPB rock unit of Salmijärvi is slightly enriched in Ti and plot in the Kirunavaara porphyries group field.

50000

Aitik host - and surrounding rocks Porphyrite group Kiruna porphyries group AMPB ABG HBG BAG QD Ti

5000

500 10 100 1000 Zr Figure 7.6. Ti-Zr discrimination diagram of Pearce (1982) with added data from Salmijärvi, Aitik and surrounding rock units. The yellow and green fields show the extent of Porphyrite and Kirunavaara porphyries group respectively. (Wanhainen et al., 2012 modified from Martinsson and Perdahl (1993, 1995).

37 8 Mineral Chemistry

In order to confirm the mineralogy observed within the petrographic microscope, to identify odd mineral assemblages, and to distinguish multiple generations of amphiboles in hornblende veins and in the matrix of rock units, mineral chemistry studies were carried out using microprobe analysis. Since amphiboles are a huge family and occur in a wide range of P-T conditions the calculation of a precise mineral might provide information about the origin of the fluids forming these hornblende veins. Additionally, feldspars and main ore mineral constituents such as chalcopyrite and pyrite grains were analysed as well. The analyses were carried out on ABG and QD matrix samples and on a few dark and light veins. The data from EPMA analysis for selected amphiboles, feldspars, and ore minerals are summarized and presented as tables in appendix 2,3 and 4.

8.1 Amphiboles In order to classify amphiboles the nomenclature of amphiboles after Hawthorne (1997) is used. The majority of amphiboles within the matrix of the Salmijärvi rock units, dark veins and zeolite veins type 1 plot within the magnesio-hornblende field with a slight dispersed trend stretching from the actinolite border toward the tschermakite field (Fig. 8.1A). Samples from the matrix of the rock units plot closer to the actinolite field while samples from the dark and zeolite veins type 1 plot closer to the tschermakite field. Amphiboles within the quartz-diorite matrix are distinctively different and plot within the gedrite field (Fig. 8.1B).

A B Quartz diorite

1 1 tremolite 0.90.9 magnesiohornblende tschermakite anthophyllite gedrite actinolite 2+ 2+ e )

0.5 0.5 Mg/(Mg+Fe ) Mg/(Mg+Fe Mg/(Mg+ F ferro- ferro- actinolite ferrohornblende ferrotschermakite anthopyllite ferrogedrite

0 0 8 7.5 7 6.5 6 5.5 8 7.5 7 6.5 6 5.5 Si Si Figure 8.1 Hornblende classification after Hawthorne (1997). A, hornblende grains within matrix of Salmijärvi rock units, dark veins and zeolite type 1 veins plotting into the magnesiohornblende field. B, hornblende grains of QD matrix plot within the gedrite field.

38 To illustrate the trend mentioned above more clearly samples are plotted in an AFM diagram as well (Fig. 8.2). Samples from the quartz-diorite matrix plot closer toward the alkali (A) enriched field, (marked with red dashed ring) while remaining samples plot along the M-F axis with a clear linear trend of increasing Fe content and much less alkali content compared to the quartz-diorite.

A M

8.2 Feldspars In addition to amphiboles that make the bulk of most dark veins, several grains of feldspars were analysed as well. Quartz and feldspars are abundant within the light veins. Cross styled quartz veins of QD stockwork, pyroxene veins within the HBG unit of the hanging wall, and the white halo around the hornblende veins were analysed as well as the matrix of ABG, AMPB and QD rock units. The results are presented in appendix 3 and plotted on a classic ternary Albite, Anorthite and Orthoclase system (Fig. 8.3). Majority of the matrix samples plot along the albite-plagioclase series within the andesine field with an average of An39 counted on 9 grains. Few samples plot within the two-feldspar phase field, ranging from An38 to An73. Samples from the cross-styled quartz veins of the QD stockwork plot within the labradorite field with an average of An55 counted on 3 grains. The samples from the plagioclase- quartz veins of the HBG unit plot within the bytownite field with an average of An71 counted on 3 grains. One sample (Sal 1008) of a zeolite veins type 1 contains pure anorthite with An99.96. The white halo mainly comprises plagioclase, but a later overprint of potassium rich feldspars are observed within and around hornblende veins type 1.

39 An Anorthite 90 Bytownite Plagioclase A 70 Labradorite

50 Andesine Two Feldspars 30 Oligoclase 10 Anorthoclase B High albite Or Ab 10 50 80

Sanadine Figure 8.3 Classic feldspars ternary diagram with fields of different plagioclases and potassium rich feldspars. The samples plot in a random fashion within the different fields and show a wide range in composition.

8.3 Ore minerals Chalcopyrite (Cpy) and pyrite (Py) constitute the bulk of mineralization at Salmijärvi and are thus important to analyse. Microprobe results show that these sulphides contain trace amounts of Ni, Co, Bi, Sn, Sb, Ag and Au in their structures. Several generations of these minerals are present both in the matrix of the rock units and in veins. Due to the extent of this study samples from the matrix of QD and ABG together with samples from the most abundant vein sets (hornblende veins and zeolite veins type 1) were analysed. See appendix 4 for microprobe results.

8.3.1 Chalcopyrite (Cpy) At least 6 distinct different Cpy grains with varying chemical composition are observed. The Cpy within the matrix of the ABG rock unit contain trace amounts of Bi, Ni, Pb, Sb and Ag, but lack Au. However, the Cpy within hornblende veins that characterize the ABG rock unit contain Au in addition to Ag but lack Bi, Ni and Co. There is also a second type of Cpy within hornblende veins that diverge from the general case of sulphides rimmed with oxides within the veins. This generation of Cpy contains Au and Sn in addition to Bi, Pb but lacks Ni, Sb and silver and has a destroyed and corroded appearance (Fig. 6.1b). Cpy within the zeolite type 1 veins lack Ni, Co, Sb and Au but contain Ag, Bi and Pb and trace amounts of sphalerite (Fig. 6.1f). Two different types of chalcopyrite are present within the matrix of the QD rock unit. The first type occur as disseminated grains free of oxide rims and contain Bi and Sn but lack Ag, Ni, Co, Pb, Sb and Au (Fig. 6.1e). The second type

40 contains Au in addition to Bi, Ni and Pb. These relationships are illustrated by a clustered column diagram in Figure. 8.4.

8.3.2 Pyrite (Py) Five different Py grains are observed as well, with the main differences based on their diverging chemical composition. Py within the ABG groundmass is enriched with Bi, Co, Ni, Pb, Sb and Au but lack Ag. Two generations of Py within the hornblende veins are observed. The first generation is rimmed by oxides and contains Ag in addition to Bi, Pb, Sb and Au. The second type is free from the oxide rim and contains traces of Bi, Co, Ni, Pb, Zn and Au but lack Ag. Py within the zeolite type 1 veins lack the distinct oxide rim as well as Au, Ag, Sb and Sn but contain Bi, Co, Ni and Pb. Py within the QD matrix are rimmed with oxides and enriched with Bi, Co, Ni, Pb as well as Ag and Au. Pyrite grains without oxide rims within this rock unit are not analysed. A clustered column diagram (Fig. 8.5) illustrates these relationships.

41 Chalcopyrite within Amphibole - biotite gneiss matrix Chalcopyrite corroded type within Amphibole - biotite gneiss matrix 10 10

Ag 1 Au 1 Ag Bi Au Co Bi Ni Co Pb Ni 0.1 0.1 Pb Sb Sb Sn Sn Zn Zn 0.01 0.01 Cu Cu FeO FeO S S 0.001 0.001

Chalcopyrite within hornblende veins Chalcopyrite within Quartz diorite matrix type 1 10 10 Ag Ag Au Au Bi 1 Bi 1 Co Co Ni Ni Pb Pb 0.1 Sb Sb 0.1 Sn

og (wt%) Sn

L Zn Zn 0.01 Cu 0.01 Cu FeO FeO S S

0.001 0.001

Chalcopyrite within Quartz diorite matrix type 2 Chalcopyrite within zeolite type 1 veins 10 10 Ag Ag Au Au Bi Bi 1 Co 1 Co Ni Ni Pb Pb 0.1 Sb 0.1 Sb Sn Sn Zn Zn 0.01 Cu Cu FeO 0.01 FeO S S

0.001 0.001

43 9 Discussion

In this section not all parts of the results are discussed due to the time limit of the study. Main focus and attention has been paid to mineralogical assemblages, geochemistry, dark veins and their origin, and ore minerals. Correlation between surrounding rock types and rock types found in Salmijärvi has also been discussed.

9.1 Mineralogy Microprobe analyses in addition to petrographic studies indicate that plagioclase and amphibole dominate the mineralogy of the Salmijärvi rocks. Also biotite, quartz, epidote, magnetite, ilmenite, pyrite and garnet are commonly present. These minerals form an assemblage typically found in basic rocks exposed to amphibolite facies metamorphism (Winter, 2001). Metamorphic conditions of 500°C-800°C and 5-11 kilobars pressure are characteristic for amphibolite facies (Barnes, 1997). The peak metamorphic phase at Aitik according to Wanhainen et al. (2012) ranges roughly between 500°C -600°C and 4-5 kilobars pressure. This suggests that the rocks of Salmijärvi also fall into P-T conditions of > 500°C and > 4 kilobars, in accordance with the observed mineralogy.

9.2 Whole rock geochemistry (WR) In the TAS (Total Alkali vs Silica) classification diagram for plutonic rocks by Cox et al., (1979) (Fig. 7.1) the data show a slight dispersed pattern moving away from the gabbro field towards the quartz diorite to syenite field meaning increase in both silica and alkali content. This can be interpreted as a result of primary sericitic and potassic alteration within a porphyry copper system and to a certain extent confirms the observations done in thin-sections. The immobile trace element plots (Zr/Ti vs Nb/Y) (Fig. 7.2) of Pearce (1996) point to an intermediate, andesitic-basaltic to andesitic precursor. Data show a dispersed pattern also here, with the majority of data plotting in the andesitic, basaltic-andesitic field stretched towards the trachy-andesite field. One sample (Sal 1029) plot clearly different from the rest of the samples and ends up in the rhyolite dacite field. This sample belongs to the HBG rock unit, strongly affected by silicification and rich in quartz veins. Compared to the TAS diagram of Cox et al., (1979) the (Zr/Ti vs Nb/Y) classification diagram of Pearce (1996) provides a better basis for rock classification. However, the pattern in Figure. 7.2 indicates that even immobile elements can be mobile at certain P-T conditions. Data plotted in the Co-Th diagram by Hastie et al., (2007) (Fig. 7.5), confirms the basaltic-andesitic trend in line with the AMF diagram of Kuno (1968) and Irving and Barager (1971)(Fig. 7.4), also pointing to a calc-alkaline to shoshonite origin. High-K calk-alkaline magmas are emplaced mainly as batholiths and plutons typically in post-collisional environments during large movements of terranes along major shear zones, more or less directly driven by oblique subduction (Liegéois et al., 1998). This post-collisional plutonism 44 generates high-K calc-alkaline magmas that either evolves or are replaced by alkaline magmatism, often as ring complexes, both marking the end of an orogeny (Liegeois et al., 1987; Sylvester, 1989; Bonin, 1990). According to Skiöld (1988) volcanic rocks of high-K calc alkaline to alkaline chemical characteristics were formed in the northern Baltic shield during a relatively short time interval between 1.91 and 1.86 Ga ago. Intermediate to felsic volcanics and similarly composed plutonic rocks in northern Norrbotten suggests that subduction processes were active ca. 1.90 Ga ago (Perdahl, 1993). At least three collisional events at 1.91 to 1.90, 1.89 to 1.88, and 1.86 to 1.84 Ga are known according to the model presented by Lahtinen (1994). The Ti-Zr diagram of Pearce (1982), (Fig. 7.6), indicates that the Salmijärvi rocks are similar to the Porphyrite group described by Martinsson and Perdahl (1993, 1995). Martinsson and Perdahl (1995) placed the Porphyrite group of rocks in a calc-alkaline volcanic series and suggested that they formed in a compressional environment based on a high content of Al and low Ti and Zr contents. The high content of alkalis was suggested as an attribute of anomalous crust rather than enrichment through differentiation. According to the findings of Perdahl (1995) the Porphyrite group was derived from a heterogeneous source, as the collected data show a wide spread when plotted in Ti-Zr diagram (Fig. 7.6). This is in line with the rocks of Salmijärvi as they also show a scattered pattern when plotted in various classification diagrams. Hence the source of the Salmijärvi rocks can be suggested as heterogeneous and belong either to reworked and replaced high-K calc alkaline magmas or simply calc alkaline magmas formed in a late stage of the Svecofennian orogeny most probable in a compressional environment associated with the subduction activities at ca. 1.90 Ga. The widespread pattern within classification diagrams could also be an affect of white and pinkish alteration rims composed mainly of feldspars around the dark veins. Few samples plot close or into the tholeiitic field (Fig. 7.4) as well as into the WPB and MORB field (Fig. 7.6). These samples might have a different source than discussed above. In research carried out by Perdahl (1995) the Kiruna porphyries plot into the WPB field and he thus suggests a mantle-derived source for the rocks. According to the findings of Perdahl (1995) emplacement of the deviating samples mentioned above into the Kiruna porphyries group might be taken into consideration. In this case the rocks plotting into WPB and MORB field might have a mantle-derived source.

45 9.3 Mineral Chemistry Origin of Dark Veins Taking into account the composition of all dark veins examined in this study, it is confirmed that magnesio-hornblende (hornblende sensu stricto) from the amphibole family is the dominant mafic constituent within the interior of the veins. Since these veins state a hydrothermal origin, understanding the nature of the fluids might lead us to understand the environment and processes giving rise to them. Hence hornblende is discussed in several aspects below. Hornblende or magnesio-hornblende occurrence with addition of biotite and chlorite within veins indicate hydrous water charged origin of fluids. Also the sulphides rimmed with oxides indicate a hydrous and oxidized environment. In a study from Zabargad Island (Red Sea), Agrinier et al. (1993) suggests that hornblende (sensu lato), tremolite and pargasite hornblende mostly occur in narrow shear zones or in veins replacing clinopyroxene. They crystalize at temperatures estimated between 700°C and 450°C, from sodium-potassium- bearing fluids (Agrinier et al., 1993). This is also observed in pyroxene veins of the Salmjijärvi deposit where hornblende replaces pyroxene in the margins of the veins (Fig. 9.3b). The process is also referred to as uralitization, which often is associated with regional, contact or metasomatic metamorphism (Andersson, 1980). Dilek and Robinson (2003) suggests that within shear zones magnesio- hornblende forms after actinolitic hornblende and is later replaced by tschermakite. This compositional variation sequence is observed within the amphiboles of dark veins in the Salmijärvi deposit (Fig. 8.1), once again confirming a hydrothermal origin. Hornblende veins type 1, hornblende veins type 3, hornblende veins type 4 and pyroxene veins display a white to pinkish halo while the hornblende veins type 2 and thin biotite veins do not. Taylor (2009) reported that quartz veins, found in New ST. Patrick copper mine in Queensland, Australia, were given by a dark rim mainly comprised of sericite. The dark rims were suggested as an alteration product of hot fluids passing through the country rock. This type of reasoning fits well with the dark veins in Salmijärvi deposit with white to pinkish rims. The main difference is that these white to pinkish rims comprises plagioclase (An36-39) and alkali-feldspars (Or53-80) (Fig. 8.3). It is convenient to suggest that hydrous sodium-potassium bearing fluids in addition to hornblende will also precipitate feldspars at the margins. Thin biotite veins and hornblende veins type 2 are far too thin and may have formed from low temperature fluids. The heat probably was not sufficient to alter the country rock to the same extent and produce the wide light rims. The alteration halo or rim width depends on the width of the mafic vein and the ΔT between fluid and country rock according to Handy and Streit (1999) (Fig. 9.1).

Figure 9.1 Diagram showing crystallization time versus vein width contoured for temperature differences. ΔT between country rock and mafic veins (Handy and Streit, 1999).

Whether these hydrothermal fluids were derived from magmatic activity or as a product of regional metamorphism is unclear. It is however convenient to predict a regional metamorphic display since no mafic body close enough to the Salmijärvi deposit with preferable size is present or reported so far to produce veins on this scale. Non-less the later option has not to be excluded due to the lack of studies toward the depth in the region. The formation temperature (450°C to 700°C) of hornblende in veins suggested by Agrinier et al. (1993) and the presence of carbonate minerals within the amphibole clusters, (Fig. 4.2e) containing REEs favours the theory of an IOCG overprinting process due to regional metamorphism as described by Wanhainen (2005). Most of the dark veins propagate parallel to foliation direction in NNW to SSE trend in Salmijärvi (Fig. 5.4). Same foliation direction is retained by rock units in the Aitik deposit and surrounding rocks and is described as a product of a regional D2 (second deformation) event by Wanhainen et al. (2012). The D2 deformation event at ca. 1.80 Ga was caused by the east-directed subduction along a N-S oriented continental margin (Weihed et al., 2002). TIB batholiths and Lina granite in Northern Norrbotten are suggested to be a product of this E- W compression (Weihed et al., 2002). Also major shear zones such as KADZ (Karesaundo-Arjeplog Deformation Zone) and NDZ (Nautanen Deformation Zone), were active at ca. 1.80 Ga and suggested to be the result of D2 deformation. The movement of these major crustal features lead to uplift of the Gällivare block according to Wanhainen et al., (2012). Hydrothermal activity of a wide range in composition associated with metamorphism, TIB and Lina magmatism in Northern Norrbotten took place at ca. 1.80 Ga, (Bergman et al., 2001). These fluids are interpreted as responsible for late stage IOCG- mineralization in the area (Billström and Martinsson, 2000).

47 Combining all information above and keeping in mind that dark veins show a late- to post-metamorphic signature propagating in most cases in the foliation direction, the author suggests that these dark veins probably are a result of E-W compression and uplift where the underlying TIB mafic units, and/or mafic successions of the Porphyrite group, acted as a source for mafic fluids rising through the fractures caused by uplift and NNW-SSE movement of the NDZ. The timing of the responsible events is highlighted in Figure. 9.2. This suggests that a magmatic source for the formation of these dark veins cannot be excluded and remains as a subject to discuss further.

TECTONISM Subduction SW-NE D1 Subduction W-E D2 Shear zones D3 D4 Haparanda + Porphyrite group MAGMATISM Perthite monzonite + Kiirunavaara group Jyryjoki Lina TIB1 TIB2 MINERALISATION Porphyry copper Iron-apatite Iron-apatite (regional) IOCG IOCG

Magnetite ? Chalcopyrite ? Pyrite ? Pyrrhotite ? TION Molybdenite ?

MINERALI- S A Bornite ? Gold ? ? Plagioclase Amphibole Pyroxene Quartz Biotite ? ? Microcline

Sericite ? Epidote ? Calcite Garnet TION Scapolite Titanite

TER A Chlorite

A L Muscovite Tourmaline Allanite Apatite Zeolites

Fluorite ? Baryte

Thaumasite ? Anhydrite ?

TIME (Ma) 1900 1800 1700 1600

9.4 Dark and light veins intercalation This study predicts that several generations of dark veins are present and has affected the rock types in the Salmijärvi deposit. Some dark veins are split apart by later light veins mainly composed of plagioclase, e.g. hornblende veins type 1 in the HBG rock unit (Fig. 6.1c). This phenomenon can also be observed in the hornblende veins type 1 in the ABG rock units over short distances (Fig. 9.3a). Taylor (2009) explains this phenomena as structural superimposition- parallel reactivation of veins. It is basically migration and infilling of alteration 48 assemblages caused within the country rock by hot fluids (source of alteration or veins) back into the veins through subsequent fracturing along the central and marginal region of the vein.

a 1

bb ABG matrix Zeolite vein

HBL HBL

Pyroxene vein

500500 umum

49 9.5 Ore Minerals Main economic minerals within the deposit are chalcopyrite and pyrite with a variable amount of gold and other trace elements bound within their structures. From mineral chemistry results, it is clear that both of these sulphides show slightly different compositions within different rock units and veins. However, the variation in chemical composition has to be interpreted by caution due to the errors that might arise from electron beam overlapping, which could lead to higher values for trace elements. The ore minerals occur as cloths, veins and dispersed grains within the matrix and within veins of varying composition. In most cases, the sulphides occurring within veins are rimmed by oxides, mainly magnetite. According to Barnes (1997), metal oxides coexist with metal sulphides that have formed during the major phases of ore deposition. However, metal oxides along with other secondary mineral phases may also form through alteration of the primary ore minerals, e.g. during retrograde metamorphism (Barnes, 1997). Ore minerals found in the veins have a much larger grain size compared to the ore minerals found in the matrix of the rock units (Fig. 4.1). Also the ore minerals in the veins have a more equant grain size and straightened grain boundaries. Remobilization during prograde metamorphism is a suggested explanation according to Marshall et al., (2000). Deformation in response to deviatoric stress is an integral part of remobilization during regional metamorphism. Thus remobilization itself can be divided into chemical, transitional and physical process (Mookherjee, 1976). This idea was pursued by Marshal and Gilligan (1987) but modified the approach by adopting solid-state mechanical transfer, liquid-state chemical transfer and mixed-state transfer. Metamorphic remobilization encloses the concept of parent or source concentration of economic value, modification involving translocation or transfer processes and a daughter or product concentration (Marshall and Gilligan, 1987, 1993) (Fig. 9.4). The daughter might reflect different chemical composition due to internal mobilization or may be spatially separate from the parent through external remobilization. High rate of internal solid-state transfer or translocation might lead to formation of remobilized deposits that is mainly composed of secondary daughter mineralization but contain remnants of primary parent mineralization as well (McClay, 1991; Larocque et al., 1993; Bodon and Valenta, 1995). Remobilization can lead to concentration of various components resulting in upgrading the ore involving grain-size coarsening and formation of discrete new minerals (Marshal et al., 2000). Coarser grain size reduces cost and improves recovery and can be pointed as beneficiation improvements in terms of economical net return and profit.

50 Product Source or parent or daughter mineralization Transfer/Modi!cation mineralization

“Primary” Processes of Remobilized Deposit Remobilization Deposit

Figure 9.4. Illustration of remobilization concept from Marshal and Gilligan, (1993).

Increased metamorphism create more complex internal chemistry within the remobilized ore minerals involving formation of discrete minerals containing certain trace elements (eg., Te Ni, Sb, Ag and Bi) (Cook 1996). This argument can be regarded as strong candidate for explanation of chemical variation within the pyrite and chalcopyrite grains analysed in the Salmijärvi rocks (Fig. 8.4 and Fig. 8.5). Other changes induced by metamorphism are the conversion of pyrite into pyrrhotite and generation of pyrrhotite through sulfidation of Fe; this becomes very obvious at upper greenschist-amphibolite facies (Vokes, 1976). Some pyrrhotite replacing pyrite within the hornblende veins (Fig. 4.1e) have been observed in Salmijärvi. This can be interpreted as an indication of the degree of metamorphism experienced by the rocks of Salmijärvi and that the dark veins containing these ore minerals are either a product or subjected to the degree of regional metamorphism mentioned above. In the copper-iron-sulphur system, the general phase relationships are shown at 1000°C, 700°C, 500°C and 300°C in Figure. 9.5. As seen in Figure. 9.5c, the chalcopyrite and pyrite stability fields emerge firstly at temperatures around 500°C and lower. Assuming that pyrite and chalcopyrite in dark veins were deposited simultaneously, either leached out from the host rock or another distal source, the temperature gradient range would still be somewhere between 500°C- to (<700°C) in order for them to coexist. This might give us a hint of the peak temperature range for the deposition or remobilization of these sulphides within dark veins but no good clues for the source of the ore minerals.

51 a b s

c d

52 10 Conclusions

Results from this study indicates that rocks of the Salmijärvi deposit falls into the same category as rocks of the Aitik deposit and Porphyrite group described by Martinsson and Perdahl (1995). These rocks have suffered multiple deformation events and metamorphism including prograde and retrograde phases. The rocks are metamorphosed to amphibolite facies, which is confirmed by the mineral assemblages observed. Apart from the primary veining and stockwork system hydrous sodium-potassium rich fluids of late syn- to post- metamorphic origin of ca.1.80 Ga. has altered these rocks and led to formation of common dark veins. The light rims around these veins are a product of alteration as the hot fluids passed through the country rock. Fluids of this late stage IOCG character seem to have played an important role, either in adding metals to the Aitik system at 1.8 Ga, or (more probable) in upgrading the system through remobilization, thus forming the southern extension.

53 11 Recommendations

In order to clarify the source of ore minerals (pyrite and chalcopyrite) within the syn- to post-metamorphic veins and in the matrix of the host rocks, a more detailed study of the main ore minerals is suggested. Furthermore, a wider study of the zeolite veins might be important since they occur abundantly in most of the rock units and in addition to pyrite, chalcopyrite and gold, also carry traces of sphalerite. Finally, the understanding of the multiple generations of hornblende veins and their style of occurrence would benefit from more detailed observations and dating in order to put them in a regional context with more accuracy than was possible in this study. A more detailed study of the hornblende banded gneiss of the hanging wall would also be relevant since it contains magnetite and traces of gold.

54 12 Acknowledgements

This project would have not been possible without the guidance and help of several special individuals who have in one way or another contributed and provided valuable assistance in the preparation and completion of this study. I wish to thank, first and foremost, my supervisors Dr. Christina Wanhainen and Professor Pär Weihed for unreserved support and tireless review of the written part. I owe my deepest gratitude to Boliden mineral AB for the financial support and especially Gregory Joslin for his openhearted support during the entire project. I would also like to thank Sofia Höglund for the effort and help with drillcores.

I would also like to express my gratitude for the encouraging staff at the ore division, individuals, who in one way or another helped and gave support. Last but not least, my family and closest friends, thank you for everything.

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61 14 Appendix 1

Major and trace element analysis of Salmijärvi rock units. HBG: Hornblende gneiss, AMPB: Amphibolite, ABG: Amphibole-Biotite gneiss, BAG: Biotite- Amphibole gneiss, QD: Quartz diorite. LOI: Loss on ignition. Major element and S data is shown in wt. %. Trace elements are shown in ppm.

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

2A% &-&& &-&& &-&& &-&& &-%& &-&' &-&' &-&* &-'' &-&( &-&, 2B %-(& %-+& &-.& %-'& %-'& ,-,& %'-%& '-)& %-%& '-)& %-*& >+ '.(-&& (,*-&& *,&-&& ',*&-&& /.)-&& )/)-&& %/&-&& '*&-&& %''*-&& .,*-&& %()*-&& >/ &-&+ &-&/ &-&, &-'& &-., &-') &-'( &-,( %-', &-(+ &-'. 5 &-&% &-%, &-%& &-&, &-&% &-&% &-&% &-&% &-&% &-&% &-&' 5) ((-&& ,,-/& %%*-*& ,,-'& )/-.& +&-+& ((-/& **-'& *'-(& +'-(& ,*-'& 5: %'&-&& %&&-&& ,&-&& '/&-&& ,&-&& %/&-&& *&-&& (&-&& ,&-&& ,&-&& (&-&& 5B )-(* +-)' .-,/ /-&' %&-'& ,-%' (-'( %%-)& (-,, +-&+ ,-*+ C' (-*% (-(. %'-+* '-/) (-'' (-+& '-&/ (-%* %-/* ,-+, %-)% D: '-&' %-// )-&' %-+( %-.' '-&, %-%' %-.% &-)( '-*/ %-&% DA %-%) %-(( %-'/ %-&+ %-,. %-*' &-)% %-%/ &-)( %-.) &-)+ E+ %)-%& '%-,& '.-(& '&-.& '%-.& '&-,& %)-+& ',-)& '(-&& '%-+& ''-(& EF (-*+ (-)' %&-*& (-(' ,-*+ ,-%& '-.' (-)& '-*% *-,& '-,. GH '-.& (-/& %(-(& (-(& '-+& '-/& '-)& (-)& (-,& (-.& (-'& G7 &-&% &-&% &-&% &-&% &-%' &-&% &-&% &-&+ &-'. &-&( &-(& G" &-., &-+) '-/& &-+& &-+* &-.+ &-() &-+' &-(+ &-), &-(* ?+ %+-*& '(-%& +&-&& '(-)& *(-+& (/-*& %(-+& ',-'& '.-+& (%-*& ''-'& ?A &-(& &-'. %-,( &-'+ &-', &-(% &-%. &-'. &-%+ &-(. &-%* 8I ,-.& +-+& ',-&& .-.& +-'& +-(& ,-&& +-)& +-/& .-(& +-+& 8F %+-+& '%-/& *(-'& %)-)& ,&-%& ',-&& %.-%& '+-,& ''-&& (&-(& '&-,& <: ,-%, *-*+ %(-/* *-'+ %%-'& +-,. ,-%( .-&% +-%% .-++ *-%) !I %'&-&& %%(-*& /*-/& '('-&& %+.-&& +)-,& ,,-&& %/%-&& %+*-*& .*-.& %,&-&& * &-&% &-&% &-&% &-&% &-(% &-&, &-&% &-+/ %-/, &-(% &-(% *I &-,) &-)' &-'( &-'+ &-%& &-+& &-/' &-(( &-(' &-). &-,+ *) &-'& &-,& %-%& &-*& '-(& &-.& &-'& %-)& (-*& %-+& %-(& *, (-,. ,-(' %%-(* (-.+ +-(& ,-(* (-') ,-/, (-,) *-/& (-*. *. %-&& %-&& (-&& %-&& '-&& %-&& ,-&& ,-&& *-&& %-&& %-&& *: (.(-&& '%*-&& %&/-&& ()(-&& *.)-&& )%&-&& /.&-&& ,((-&& *&,-&& +&)-&& ,/'-&& ;+ &-(& &-*& %-.& &-.& &-(& &-,& &-(& &-,& &-,& &-*& &-,& ;I &-*. &-+% %-/' &-*% &-+' &-+' &-(+ &-** &-(' &-/' &-(' ;) &-&% &-&% &-&% &-&% &-&) &-&. &-&' &-&* &-+) &-&+ &-&. ;J '-+) *-,, ''-/& +-,( )-*' +-%% ,-+% +-%% *-&/ *-/, *-.( ;- &-*& &-*& &-*& &-)& &-*& &-*& &-*& &-*& &-*& &-*& &-*& ;, &-(% &-'/ %-(/ &-'* &-'. &-(' &-%) &-'. &-%* &-() &-%. K %-%& '-'' /-') (-,) '-)+ '-(* %-&) ,-/. *-(& '-'& %-.& L '')-&& %,.-&& *+-&& %.+-&& %)*-&& '.&-&& %+*-&& '',-&& /+-&& '/*-&& %&+-&& M %-&& '-&& '-&& '-&& *-&& %-&& %-&& ,-&& +*-&& %-&& /-&& N %)-.& %/-.& /,-)& %.-&& %.-)& '&-(& %'-&& %.-*& %&-%& '*-(& %&-*& NI %-// %-., )-&. %-+& %-*+ %-), %-&+ %-.% &-)' '-,+ &-)* O: %&&-&& %,&-&& *'&-&& %(&-&& %&&-&& %%&-&& %(&-&& %*&-&& %(&-&& %,&-&& %(&-&&

62 Appendix 1. Cont.

ABG ABG ABG ABG ABG ABG ABG BAG BAG QD !"#$%&'( !"#$%&') !"#$%&*% !"#$%&'+ !"#$%&', !"#$%&'- !"#$%&'' !"#$%&'& !"#$%&'. !"#$%&*& .%/( .'/' ../- ,&/+ ,%/* ,&/) .*/% .(/+ .'/* ,(/. %,/% %,/- %-/% %./* %*/- %./. %./( %-/%. %,/. %./'. %&/. +/(% )/,) ,/+ +/'. ,/. +/+, %% %&/(. ./-% ,/) ,/') */- */.. (/)' (/&% )/)' ./*) ./+' ./'* */*( '/,( (/&+ (/)( %/-% (/%' */(' '/)+ '/*+ %/+ '/-+ '/., */,, '/,* '/*- '/-, (/+( ./%+ '/-+ */&* '/%) */%* (/. '/%, '/,% ./%( '/,) %/,) '/.* '/&( &/&% &/&% &/&% &/&% &/&% &/&% &/&% &/&% &/&% &/&% &/-- &/- &/-% &/.* &/*' &/*) &/,. &/+. &/, &/*+ &/(- &/(% &/%* &/%' &/%' &/%, &/*+ &/&+ &/(* &/(* &/(- &/(- &/(- &/%+ &/(, &/(, &/(' &/(, &/', &/%- &/&, &/&) &/&, &/&- &/&* &/&. &/&, &/&+ &/&- &/&- &/%' &/%+ &/%( &/%, &/%, &/(, &/%) &/&* &/'* &/(( &/,- &/)) (/(- %/&' %/)+ %/(' %/( &/(( &/-, %/'( +)/%- ++/(. ++/&% ++/.& ++/++ +)/(- %&%/-* +)/+. ++/() %&&/')

&/&'' &/&,* &/&,( &/&-, &/%++ &/&%) &/&.) &/&%. &/&%( &/%)% %/- '/% , (/) */) (/' (/* (/+ */% (/% %&.. %.,& +,& %(+. %()& (%-& %*&. '*) ()&& %--& &/(( &/) &/+* &/-+ (/,% &/' &/.+ &/%' &/'' %/%. &/&% &/&, &/&( &/&- &/&% &/&% &/&. &/&% &/&' &/%% +&/+ +'/. +-/. -)/' ,,/, *,/+ +,/% ,' %%,/. '. ,& .& .& *& '& '& *& '& ,& ,& ./-. */,* */.- */.. %/'' */%) %/&) (/'* (/' &/-) '/() '/%. */%+ (/*% (/,) %/)) */%+ */*% '/.) %/) %/)' %/-. (/'' %/*( %/.* %/%- (/(+ (/.+ %/)+ %/&' %/*- %/.- %/,) %/%. %/() &/-- %/-) %/,% (/'% &/-- %+/+ %)/) ('/- %)/, %)/+ %+/. %+/) %+/' %-/, (&/, */*, */%+ ./'- '/% '/.. (/&( ./(+ */), ./-% (/( (/% (/( (/* (/, '/- */' ( (/) (/* '/' &/&( &/&+) &/*-+ &/%%' &/&,. &/&(. &/&+( &/&'' &/&(' &/'', &/,* &/,( &/)( &/*) &/.( &/'+ &/) &/)) &/,, &/'. -&/* .&/* *+/, *%/' '%/, ('/% .'/* ()/. ,,/+ %-/' &/(- &/(, &/'* &/(% &/(( &/(( &/'' &/'+ &/(, &/%, ./* ./- ,/) ,/) -/* )/+ */) -/. -/% ,/- **/+ ',/. *./% ()/+ ()/- %-/' *(/' (+ .%/( %, %(/(. %&/&. %%/+ )/&, -/** */+ %%/* -/(. %'/. */&* %-&/. %((/. %((/. %&'/. +&/( %*-/. %&+ .,/- +(/% ,,/* &/&* &/%+ (/.' &/%' (/%+ &/)( &/&) &/&- &/&' &/,( &/* %/,) %/(% %/&) %/&% &/%% %/&+ &/)+ &/.. %/&+ &/. &/) '/. &/- %/) &/+ &/, &/- &/* (/+ ,/'% ./-) -/'- */'- */) (/- -/&( ./+* )/(, (/+( ( % * % ( ' ( ( ( ( .*( ,)- .*( ,*, '-, *(+ .*% --, ,&, ,,+ &/' &/' &/* &/. &/. &/, &/' &/. &/' &/* &/.. &/., &/-% &/*% &/*, &/(+ &/-% &/-( &/,- &/'( &/&' &/% &/(% &/% %/.+ &/(. &/&. &/&( &/&% &/%+ ,/+* %&/). +/-, %'/' -/, )/+* )/+, -/&( +/(* , &/. &/. &/. &/. &/. &/. &/. &/. &/. &/. &/(- &/(+ &/', &/(( &/(* &/(% &/') &/'+ &/() &/%- %/.* %/), '/-* (/(' (/,% (/)* %/-+ %/+' %/-% (/*, (.* (%, %(& %.. ++ ), (%+ (-% (%- %&- % ' ( ' . (( % % , , (&/% %-/, ((/) %'/) %./- %%/, (*/. (./- %+/, %&/+ %/,- %/,. (/%. %/'- %/*' %/(+ (/&. (/* %/,' &/+. +& +& %&& +& %,& %)& )& %%& %%& %.&

63 15 Appendix 2

Microprobe analyses of amphiboles within host rocks; dark vein and zeolite type 1 veins.

!"#$%&'() %%*+,-./%%0"1% %%%*(23%% %%%4(23%% %%%5.326% %%%7/%%%% %%%8'2%%% %%%892%%% %%%:+2%%% %%%0+32%% %%%;32%%% %%%:<326% !!"#$%&!! =>? *+.%@A@3 BC1C@ A1DE F163 @B13@ A1BE @613D @@1E6 @1AF A16@ A1A@ GC1DB =>? *+.%@A@3 BG1EC A13E C1AA @616@ A1D6 @B1BD @31B@ A1F6 A13B A1AA GF1CA 58H> *+.%@A3@ BE1G3 A1EF C1FG @E1F3 A1B3 @@1E@ @@1GG @1@E A1CA A1A6 GF136 58H> *+.%@A3@ BG13E A13C E1B@ @D1CC A13C @61AF @31@6 A1FA A1DB A1AA GF1D3 58H> *+.%@A3@ BF1GF A13@ E1E@ @E1A3 A16B @31F6 @3136 A1G@ A1BC A1A6 GF1E6 58H> I+.%@A3@ BC1EB A13C C1DF @E1FE A1B@ @31AC @31@B A1G3 A1DD A1A@ GF1BE 58H> *+.%@A3@ BC1AA A1EB C1GG @C1E3 A16A @@1GB @@1GB @13@ A1E3 A1A@ GG13C 5>? *+.%AA3 DA1B3 A136 B133 @D13E A1D6 @61BF @@1G6 A1DB A163 A1A@ GE1GB 5>? *+.%AA3 BD1CF A1E3 F1@6 @C1BA A1GE @@13B @@1EG @13C A1CD A1AB GC1FF 5>? *+.%AA3 BB1@E A1BG G1BA @G1AC A1CA G1FD @@1AB @16F @1AA A1AA GC1AG 5>? *+.%AA3 BB1AA A1EF G16@ @F13E A1CC @A16C @@1BF @16D @1AE A1AA GC13F 5>? *+.%@A33 DA136 A16D D1GG @61GG A1D6 @B1AG @31EA A1CD A1BB A1A3 GF1GG 5>? *+.%@A33 BG1EE A1BE E1@@ @B1BE A1E@ @61GA @313F A1CB A1D6 A1AB GF1CG 5>? *+.%@A33 DA1AB A16A D1DG @61BA A1EE @B1EA @31DB A1FA A16F A1AA GF163 5>? *+.%@A33 DA1ED A13B D1EC @61AF A1D3 @61G6 @31DC A1C6 A1BE A1A@ GC1FE 5>? *+.%@A3F BE1E3 A1DE F1FF @D1FE A133 @31A6 @@1FF @1@G A1D@ A1AA GC1CD JK *+.%@A@F 6C1@A @1GD @B1AB @G1DD A1DB @31@E A1A@ A1AB F16G A1A6 G61F@ JK *+.%@A@F 6C1C@ 313G @B1BB @G1BC A1DF @@1DB A1A@ A1AG F1DB A1AA GB1EC JK *+.%@A@F 6F1A3 @1GC @B1D6 3A1AG A1EF @@1GB A1A3 A1AF G13C A1AD GE1EB

64 16 Appendix 3

Microprobe analysis of feldspars in host rocks, dark veins, and zeolite type 1 veins.

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

65 17 Appendix 4

Microprobe analysis of representative pyrite and chalcopyrite grains within host rocks, dark veins, and zeolite type 1 veins. 5958 5955 5955 594< 5955 4968 5955 59== 5955 5958 5955 5954 =7966 ;5974 0A@()? */0+ 4549<6 123%4584 0-I%L?(' CBA *+, 595: 5955 5955 5985 5955 5955 5954 59:= 595: 5955 5955 <79:< :5955 :=974 :89<6 /2)@(G 123%4544 CBA *+, 5955 5955 595: 5948 5955 5955 5955 59=4 5958 5955 5955 <<957 :59=4 :=9=7 ::9>4 K*I= 123%4544 0A *+, 5955 5955 5957 5946 5955 59:7 595: 59;6 5955 5955 5958 5955 =>9>> ;:9:: K*I: 454988 123%4544 @(P N()D%"G(O?% 0A *+, 595: 5955 595: 5957 5955 5955 5955 59=5 5958 5955 5955 5954 ;:958 =>9=6 K*I8 45595> N()D"&)% 123%4544 "G(O?%@(P *+, 5958 5955 595< 594= 5955 5955 5955 5948 5955 5954 5955 :898: <5967 :4954 8694; K*I4 C0E%.F1 123%4544 CBA *+, 5955 5955 5958 594< 5955 5955 595= 598= 5954 5955 5955 5955 ;:9=7 =698= K*I: 45498: 123%558 0A *+, 5958 5955 5955 5955 5955 5955 59=; 59=7 595: 5955 5955 5955 :79>= >597; K*I: 4559=> 123%558 0A *+, 5955 5955 5955 5957 5955 5955 5955 59=6 5955 5955 5955 5955 ;:984 =>9<5 4559>7 123%558 /2)@(G -. CBA 5955 5955 5955 5956 5955 5955 5955 59:8 5958 5955 5955 :=944 <<98< ::9;< :4946 /2)@(G 123%4547 -. CBA 5955 5955 5956 595: 5955 5955 5954 59:= 5955 5955 5955 ::98: ::9:: :=95; /2)@(G 45495; @(P 123%4547 N()D%"G(O?% 0A -. 5954 5955 5954 59:8 5955 595: 5948 59;4 5955 5955 598= 5955 ;59<7 <<9:= =694: /2)@(G @(P 123%4547 N()D%"G(O?% -. CBA 5955 5955 5955 594; 5955 5955 5955 59:> 5955 5958 5955 ::94< <<96= ::98: :8975 /2)@(G N()D"&)% "G(O?%@(P 123%4547 0A JI4% *+, 595: 5955 595; 598: 5955 5955 5955 59;: 5955 5955 5955 5955 ;:98= =>97> 4559<= 123%4557 JI4 1BD *+, 5955 5955 4955 5955 5955 5954 5955 598< 5955 5956 594< 5968 >;985 ::956 4559;> 123%4556 0A JI4 *+, 5955 5955 5955 5984 5955 5954 5954 59:> 5955 5955 5955 598= =6958 ;:95> 4559<4 123%4556 JI4 CBA *+, 5958 5955 5955 5985 5955 5955 5955 594= 5955 5955 5955 :=94> :494> :=9;< 45598> 123%4556 !"#$%&'() !"#$%&'() /2)@(GHI?(' '''*+'''' '''*,'''' '''*-'''' '''./'''' '''01'''' '''0)'''' '''0-'''' '''2&3''' '''(/'''' '''45'''' '''!''''' '''!5'''' '''!6'''' '''76'''' ''8)9"%'' /('?@23%)AB? FG)@2%('M" ! !