DOCSLIB.ORG

Clay Veins: Their Occurrence, Characteristics, and Support

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Clay Veins: Their Occurrence, Characteristics, and Support Bureau of Mines Report of Investigations/ 1987 Clay Veins: Their Occurrence, Characteristics, and Support By Frank E. Chase and James P. Ulery UNITED STATES DEPARTMENT OF THE INTERIOR Report of Investigations 9060 Clay Veins: Their Occurrence, Characteristics, and Support By Frank E. Chase and James P. Ulery UNITED STATES DEPARTMENT OF THE INTERIOR Donald Paul Hodel, Secretary BUREAU OF MINES Robert C. Horton, Director Library of Congress Cataloging in Publication Data : Chase, Frank E. Clay veins : their occurrence, characteristics, and support. (Report of investigations/United States Department of the Interior, Bureau of Mines ; 9060) Bibliography: p. 18-19. Supt. of Docs. no.: I 28.23: 9060. 1. Ground control (Mining) 2. Clay veins. 3. Coal mines and mining-Safety measures. I. Ulery, J. P. (James P.) 11. Title. 111. Series: Report of investigations (United States. Bureau of Mines) ; 9060. TN23.U43 86-600245 CONTENTS Page Abstract ....................................................................... Introduction................................................................... Clay vein origins .............................................................. Clay vein occurrences.......................................................... Depositional setting and interpretations ....................................... Clay vein composition.......................................................... Coalbed and roof rock characteristics .......................................... Roof support................................................................... Prediction and mine plan modifications ......................................... Conclusions and recommendations................................................ References..................................................................... ILLUSTRATIONS Clay vein occurrence map for the Eastern United States .................... Single-feeder clay vein ................................................... Multiple-feeder clay vein ................................................. Coalbed bedding plane warping in proximity to a clay vein ................. Clay-vein-associated fracture plane ....................................... Clay-vein-related fault plane ............................................. Major and minor slickenside plane sets associated with a large clay vein .. Clay-vein-associated slickenside plane sets displaying a "V-up" pattern ... Steel mats effectively controlling fragmented clay vein roof with slickensides............................................................. Rib-line clay vein ........................................................ Clay-vein-associated fracture and fault plane bolting diagrams ............ Roof trusses effectively controlling clay-vein-disturbed roof ............. Histogram of bimodal clay vein distribution............................... Rose diagram of multidirectional clay vein distribution ................... Distribution of clay veins on a synclinal flank ........................... Schematic drawing illustrating up-dip shifting of clay-vein-disturbed rock ..................................................................... Distribution of clay veins and paleochannels in mine workings ............. TABLE 1 . Roof instability associated with different clay vein strikes.............. UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT feet m meter inch Pet percent inch per day CLAY VEINS: THEIR OCCURRENCE, CHARACTERISTICS, AND SUPPORT By Frank E. Chase1and James P. Uleryl ABSTRACT Clay veins found in coal mines have caused numerous injuries and fa- talities. These structures plague all phases of mining, including entry development, pillar recovery, and panel extraction. Clay veins also in- crease production costs and may disrupt or halt mining. These detri- mental aspects have prompted the Bureau of Mines to investigate the physical characteristics of and roof instability problems associated with clay veins. This was accomplished by observing and mapping clay veins in surface and underground mi-nes. The occurrence and origins of clay veins were also investigated to determine predictive capabilities. The investigators found that clay veins normally occur in more stable, less rapidly subsiding coal basins. Clay veins result when tensile stresses develop fissures which are later infilled. These fissures can be propagated by compactional processes and/or tectonic stresses active during and subsequent to coalification. The Bureau also found that associated faults, fractures, and slicken- side planes commonly parallel clay veins and disrupt the lateral con- tinuity of the immediate and, sometimes, main roof. When clay veins parallel or subparallel the direction of face advance, the roof is seg- mented into cantilever beams, causing unstable conditions. Consequent- ly, the strata on either side of the clay veins should be bolted and strapped together to form a beam. '~eolo~i4t,Pittsh~~rgh Research Center, Rurenu of Mines, Pittshrrrqh, PA. INTRODUCTION Accidental roof falls continue to be Previous studies have indicated that a major cause of injuries and fatal- clay veins (also referred to as clay ities in underground coal mines (26).- dikes, horsebacks, or mudslips) were The Bureau of Mines, in keeping with formed by either compactional processes its goal of promoting a safer work envi- or tectonic stresses. Occurrence infor- ronment, has conducted several in-mine mation collected during this investi- investigations to determine the geo- gation seems to confirm both theories. logic structures and conditions respon- Furthermore, since clay veins are ac- sible for accidental roof falls. These tually infilled fissures, the authors studies have confirmed that many roof contend that any compactional process or falls can be correlated with specific ground stress capable of developing a geologic features. Moreover, the Bu- fissure, or fracture that can later reau's investigations have enabled lim- widen, can result in the Eormation of a ited prediction of occurrences of these clay vein. hazardous geologic features in [lnlni i~ed portions of the coalbed. CLAY VEIN ORIGINS Clay veins are infilled f issllres. Gresley (z), and Oldham (E), have These fissures developed when tensile attributed fissures to earthquake dis- stresses ruptured the coa,l and adjacent turbances, which are often related to sediments during or after the coalifica- tectonic activity. tion process. Previous studies have in- Fissures may be infilled as a result of dicated that the fissures responsible for gravity, downward-percolating ground wa- clay vein formation can be propagated by ters, or compactional pressures which compactional processes and/or tectonic cause unconsolidated clays or thixotropic (regional or mountain-building) stresses sands to flow into the fissures. This active during and subsequent to coalifi- latter (plastic-f low) nethod of infilling cation. Theories advocating cornpaction occurred in the Upper Freeport Coalbed in suggest that the fissures resulted from Garrett County, MD, where high compres- the unequal shrinkage of peat (24) or sive st rc?.;l;cs have pressure-injected un- from differential compaction (iy 30). consolidated underclays into fissures Proponents for a tectonic origin inchl-de associated with floor heave. Some of ?kCulloch (14), Price (221, and Smith the fissures intersect coal ribs, forming (25). other investigators , including mining-induced clay veins. CLAY VEIN OCCURRENCES Clay veins occur in the United States, mine observations. Other clay vein oc- the United Kingdom, Czechoslovakia, New currence information uas obtained from Zealand, and elsewhere. This investi- the Mine Safety and 'riealtl~Administration gation was limited to the eastern United (MSHA), State enforcement agencies, State States (fig. 1) and includes portions of the Arkoma, Illinois, Northern and South- 3~lthough sedimentary dike or clastic ern Appalachian, and Warrior Coal Basins. dike is the more exact geologic term for The information shown in figure 1 was an approximately vertical, tabular, sed- compiled by Bureau personnel based on imentary infilled discontinuity, the term "clay vein" is used here because it is 2~nderlinednumbers in parentheses re- firmly es tahlished in the coalfields that fer to items in the list of references at have the greatest incidence of related the end of this report. injuries and fatalities. FIGURE 1.-Clay vein occurrence map for the Eastern United States, after McNeal (75). geological surveys, and mine personnel containing clay veins were deposited in throughout the eastern and central United various marine and nonmarine environ- States. ments. Individual roof rock types con- Distribution data indicate that clay taining clay veins incllide thin, massive, veins commonly occur with varying Ere- or interbedded limestnnes, mudstones, quency in the Illinois and Northern sandstones, shales, and siltstones; how- Appalachian Coal Basins fig 1 The ever, clay veins occur less frequently immediate and main roofs above co:ilheds under massive sandstone units. DEPOSITIONAL SETTING AND INTEKPRE'rATIONS Depositional conditions in the investi- widespread presccvat ion of fossilized gated portions of the Illinois and North- trees 1cettl.ehottoms). This is consis- ern Appalachian Basins were similar in tnt with information the Bureau has col- that both basins were deposited on more lected in the Southern Appalachian and stable (less rapidly subsiding) platforms i-Jarrior Basins. with correspondingly slower rates of sed- Depositional conditions
Load more

Recommended publications
  • Significance of Brittle Deformation in the Footwall
    Journal of Structural Geology 64 (2014) 79e98 Contents lists available at SciVerse ScienceDirect Journal of Structural Geology journal homepage: www.elsevier.com/locate/jsg Significance of brittle deformation in the footwall of the Alpine Fault, New Zealand: Smithy Creek Fault zone J.-E. Lund Snee a,*,1, V.G. Toy a, K. Gessner b a Geology Department, University of Otago, PO Box 56, Dunedin 9016, New Zealand b Western Australian Geothermal Centre of Excellence, The University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia article info abstract Article history: The Smithy Creek Fault represents a rare exposure of a brittle fault zone within Australian Plate rocks that Received 28 January 2013 constitute the footwall of the Alpine Fault zone in Westland, New Zealand. Outcrop mapping and Received in revised form paleostress analysis of the Smithy Creek Fault were conducted to characterize deformation and miner- 22 May 2013 alization in the footwall of the nearby Alpine Fault, and the timing of these processes relative to the Accepted 4 June 2013 modern tectonic regime. While unfavorably oriented, the dextral oblique Smithy Creek thrust has Available online 18 June 2013 kinematics compatible with slip in the current stress regime and offsets a basement unconformity beneath Holocene glaciofluvial sediments. A greater than 100 m wide damage zone and more than 8 m Keywords: Fault zone wide, extensively fractured fault core are consistent with total displacement on the kilometer scale. e Fluid flow Based on our observations we propose that an asymmetric damage zone containing quartz carbonate Hydrofracture echloriteeepidote veins is focused in the footwall.
    [Show full text]
  • Geology of the Kranzberg Syncline and Emplacement Controls of the Usakos Pegmatite Field, Damara Belt, Central Namibia
    GEOLOGY OF THE KRANZBERG SYNCLINE AND EMPLACEMENT CONTROLS OF THE USAKOS PEGMATITE FIELD, DAMARA BELT, CENTRAL NAMIBIA by Geoffrey J. Owen Thesis presented in fulfilment of the requirements for the degree Master of Science at the University of Stellenbosch Supervisor: Prof. Alex Kisters Faculty of Science Department of Earth Sciences March 2011 i DECLARATION By submitting this thesis electronically, I declare that the entirety of the work contained therein is my own, original work, that I am the sole author thereof (save to the extent explicitely otherwise stated), that reproduction and publication thereof by Stellenbosch University will not infringe any third party rights and that I have not previously in its entirety or in part submitted it for obtaining any qualification. Signature: Date: 15. February 2011 ii ABSTRACT The Central Zone (CZ) of the Damara belt in central Namibia is underlain by voluminous Pan-African granites and is host to numerous pegmatite occurrences, some of which have economic importance and have been mined extensively. This study discusses the occurrence, geometry, relative timing and emplacement mechanisms for the Usakos pegmatite field, located between the towns of Karibib and Usakos and within the core of the regional-scale Kranzberg syncline. Lithological mapping of the Kuiseb Formation in the core of the Kranzberg syncline identified four litho-units that form an up to 800 m thick succession of metaturbidites describing an overall coarsening upward trend. This coarsening upwards trend suggests sedimentation of the formation’s upper parts may have occurred during crustal convergence and basin closure between the Kalahari and Congo Cratons, rather than during continued spreading as previously thought.
    [Show full text]
  • Silica Gel Formation During Fault Slip: Evidence from The
    *Manuscript Publisher: GSA Journal: GEOL: Geology Article ID: G34483 1 Silica gel formation during fault slip: Evidence from the 2 rock record 3 J.D. Kirkpatrick1*, C.D. Rowe2, J.C. White3, and E.E. Brodsky1 4 1Earth & Planetary Sciences Department, University of California–Santa Cruz, 1156 5 High Street, Santa Cruz, California 95064, USA 6 2Department of Earth & Planetary Sciences, McGill University, 3450 University Street, 7 Montréal, QC H3A 0E8, Canada 8 3Department of Earth Sciences, University of New Brunswick, 2 Bailey Drive, 9 Fredericton, New Brunswick E3B 5A3, Canada 10 *Current address: Department of Geosciences, Colorado State University, 1482 Campus 11 Delivery, Fort Collins, Colorado 80523, USA. 12 ABSTRACT 13 Dynamic reduction of fault strength is a key process during earthquake rupture. 14 Many mechanisms causing coseismic weakening have been proposed based on theory 15 and laboratory experiments, including silica gel lubrication. However, few have been 16 observed in nature. Here we report on the first documented occurrence of a natural silica 17 gel coating a fault surface. The Corona Heights fault slickenside in San Francisco, 18 California, is covered by a shiny layer of translucent silica. Microstructures in this layer 19 show flow banding, armored clasts and extreme comminution compared to adjacent 20 cataclasites. The layer is composed of ~100 nm to 1 µm grains of quartz, hydrous 21 crystalline silica, and amorphous silica, with 10–100 nm inclusions of Fe oxides and 22 ellipsoidal silica colloids. Kinematic indicators and mixing with adjacent cataclasites Page 1 of 15 Publisher: GSA Journal: GEOL: Geology Article ID: G34483 23 suggest the shiny layer was fluid during fault slip.
    [Show full text]
  • Structural Control of Uranium-Bearing Vein Deposits and Districts in the Conterminous United States
    Structural Control of Uranium-Bearing Vein Deposits and Districts in the Conterminous United States GEOLOGICAL SURVEY PROFESSIONAL PAPER 455-G Prepared on behalf of the U.S. Atomic Energy Commission Structural Control of Uranium-Bearing Vein Deposits and Districts in the Conterminous United States By FRANK W. OSTERWALD GEOLOGY OF URANIUM-BEARING VEINS IN THE CONTERMINOUS UNITED STATES GEOLOGICAL SURVEY PROFESSIONAL PAPER 455-G Prepared on behalf of the U.S. Atomic Energy Commission UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1965 UNITED STATES DEPARTMENT OF THE INTERIOR STEWART L. UDALL, Secretary GEOLOGICAL SURVEY Thomas B. Nolan, Director For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 30 cents (paper cover) CONTENTS Page Abstract___________________________________ 121 Structural environment of uranium districts..__________ 134 Introduction.______________________________________ 121 Districts adjacent to large-scale structural features.- 136 Shape of uranium-bearing veins_____________________ 122 Districts in crystalline-rock masses.______________ 140 Internal structure of ore shoots within veins._________ 123 Districts with linked tension fractures between Structural control of deposits-___-__-__-_____-_.______ 123 large-scale faults or shear zones_______________ 141 Fractures and fracture zones_____________________ 123 Summary. ___________________-__--_-__--_-___--____ 142 Fractures cutting favorable host rocks..___.______- 130 Literature cited__________________________________ 144 ILLUSTRATIONS Page FIGUBE 44. Sketch showing structural characteristics of pitchblende-bearing veinlets between footwall and hanging wall seams, Carroll mine.______--_-_________________________________________-_____-____--_-----__------- 123 45-46. Photographs of 45. Brecciated fault contact between steeply dipping Paleozoic(?) limestone and granitic rocks of Cretace- ous(?) age, at Hoping No.
    [Show full text]
  • Seismic Moment and Recurrence: Microstructural and Mineralogical
    Seismic Moment and Recurrence: Microstructural and mineralogical characterization of rocks in carbonate fault zones and their potential for luminescence and ESR dating Evangelos Tsakalosa,b,*, Maria Kazantzakia, Aiming Linb, Yannis Bassiakosa, Eleni Filippakia , Nishiwaki Takafumib a Laboratory of Luminescence dating, Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research, N.C.S.R. “Demokritos”, Athens, 153 10, Greece b Department of Geophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan *Corresponding Author: Evangelos Tsakalos, Laboratory of Luminescence dating, Institute of Nanoscience and Nanotechnology, National Centre for Scientific Research, N.C.S.R. “Demokritos”, Aghia Paraskevi, 153 10, Athens, Greece. E-mail: [email protected]; Tel.: +306974561999. Keyword: fault rocks; fault mirrors; carbonate fault zones; absolute dating; mineralogy; microstructural analysis Abstract: The important question of absolute dating of seismic phenomena has been the study of several researchers over the past few decades. The relevant research has concentrated on “energy traps” of minerals, such as quartz or feldspar, which may accumulate chronological information associated with tectonic deformations. However, the produced knowledge so far, is not sufficient to allow the absolute dating of faults. Today, Luminescence and Electron Spin Resonance (ESR) dating methods could be seen as offering high potential for dating past seismic deformed features on timescales ranging from some years
    [Show full text]
  • Middle-Upper Miocene Stratigraphy of the Velarde Graben, North-Central New Mexico: Tectonic and Paleogeographic Implications D
    New Mexico Geological Society Downloaded from: http://nmgs.nmt.edu/publications/guidebooks/55 Middle-Upper Miocene stratigraphy of the Velarde Graben, North-Central New Mexico: Tectonic and paleogeographic implications D. J. Koning, S. B. Aby, and N. Dunbar, 2004, pp. 359-373 in: Geology of the Taos Region, Brister, Brian; Bauer, Paul W.; Read, Adam S.; Lueth, Virgil W.; [eds.], New Mexico Geological Society 55th Annual Fall Field Conference Guidebook, 440 p. This is one of many related papers that were included in the 2004 NMGS Fall Field Conference Guidebook. Annual NMGS Fall Field Conference Guidebooks Every fall since 1950, the New Mexico Geological Society (NMGS) has held an annual Fall Field Conference that explores some region of New Mexico (or surrounding states). Always well attended, these conferences provide a guidebook to participants. Besides detailed road logs, the guidebooks contain many well written, edited, and peer-reviewed geoscience papers. These books have set the national standard for geologic guidebooks and are an essential geologic reference for anyone working in or around New Mexico. Free Downloads NMGS has decided to make peer-reviewed papers from our Fall Field Conference guidebooks available for free download. Non-members will have access to guidebook papers two years after publication. Members have access to all papers. This is in keeping with our mission of promoting interest, research, and cooperation regarding geology in New Mexico. However, guidebook sales represent a significant proportion of our operating budget. Therefore, only research papers are available for download. Road logs, mini-papers, maps, stratigraphic charts, and other selected content are available only in the printed guidebooks.
    [Show full text]
  • Anja SCHORN & Franz NEUBAUER
    Austrian Journal of Earth Sciences Volume 104/2 22 - 46 Vienna 2011 Emplacement of an evaporitic mélange nappe in central Northern Calcareous Alps: evidence from the Moosegg klippe (Austria)_______________________________________________ Anja SCHORN*) & Franz NEUBAUER KEYWORDS thin-skinned tectonics deformation analysis Dept. Geography and Geology, University of Salzburg, Hellbrunnerstr. 34, A-5020 Salzburg, Austria; sulphate mélange fold-thrust belt *) Corresponding author, [email protected] mylonite Abstract For the reconstruction of Alpine tectonics, the Permian to Lower Triassic Haselgebirge Formation of the Northern Calcareous Alps (NCA) (Austria) plays a key role in: (1) understanding the origin of Haselgebirge bearing nappes, (2) revealing tectonic processes not preserved in other units, and (3) in deciphering the mode of emplacement, namely gravity-driven or tectonic. With these aims in mind, we studied the sulphatic Haselgebirge exposed to the east of Golling, particularly the gypsum quarry Moosegg and its surroun- dings located in the central NCA. There, overlying the Lower Cretaceous Rossfeld Formation, the Haselgebirge Formation forms a tectonic klippe (Grubach klippe) preserved in a synform, which is cut along its northern edge by the ENE-trending high-angle normal Grubach fault juxtaposing Haselgebirge to the Upper Jurassic Oberalm Formation. According to our new data, the Haselgebirge bearing nappe was transported over the Lower Cretaceous Rossfeld Formation, which includes many clasts derived from the Hasel- gebirge Fm. and its exotic blocks deposited in front of the incoming nappe. The main Haselgebirge body contains foliated, massive and brecciated anhydrite and gypsum. A high variety of sulphatic fabrics is preserved within the Moosegg quarry and dominant gyp- sum/anhydrite bodies are tectonically mixed with subordinate decimetre- to meter-sized tectonic lenses of dark dolomite, dark-grey, green and red shales, pelagic limestones and marls, and abundant plutonic and volcanic rocks as well as rare metamorphic rocks.
    [Show full text]
  • U. S. Department of Agriculture Technical Release No
    U. S. DEPARTMENT OF AGRICULTURE TECHNICAL RELEASE NO. 41 SO1 L CONSERVATION SERVICE GEOLOGY &INEERING DIVISION MARCH 1969 U. S. Department of Agriculture Technical Release No. 41 Soil Conservation Service Geology Engineering Division March 1969 GRAPHICAL SOLUTIONS OF GEOLOGIC PROBLEMS D. H. Hixson Geologist GRAPHICAL SOLUTIONS OF GEOLOGIC PROBLEMS Contents Page Introduction Scope Orthographic Projections Depth to a Dipping Bed Determine True Dip from One Apparent Dip and the Strike Determine True Dip from Two Apparent Dip Measurements at Same Point Three Point Problem Problems Involving Points, Lines, and Planes Problems Involving Points and Lines Shortest Distance between Two Non-Parallel, Non-Intersecting Lines Distance from a Point to a Plane Determine the Line of Intersection of Two Oblique Planes Displacement of a Vertical Fault Displacement of an Inclined Fault Stereographic Projection True Dip from Two Apparent Dips Apparent Dip from True Dip Line of Intersection of Two Oblique Planes Rotation of a Bed Rotation of a Fault Poles Rotation of a Bed Rotation of a Fault Vertical Drill Holes Inclined Drill Holes Combination Orthographic and Stereographic Technique References Figures Fig. 1 Orthographic Projection Fig. 2 Orthographic Projection Fig. 3 True Dip from Apparent Dip and Strike Fig. 4 True Dip from Two Apparent Dips Fig. 5 True Dip from Two Apparent Dips Fig. 6 True Dip from Two Apparent Dips Fig. 7 Three Point Problem Fig. 8 Three Point Problem Page Fig. Distance from a Point to a Line 17 Fig. Shortest Distance between Two Lines 19 Fig. Distance from a Point to a Plane 21 Fig. Nomenclature of Fault Displacement 23 Fig.
    [Show full text]
  • Viewing Many Matrix Texture
    Hashimoto and Yamano Earth, Planets and Space 2014, 66:141 http://www.earth-planets-space.com/66/1/141 LETTER Open Access Geological evidence for shallow ductile-brittle transition zones along subduction interfaces: example from the Shimanto Belt, SW Japan Yoshitaka Hashimoto* and Natsuko Yamano Abstract Tectonic mélange zones within ancient accretionary complexes include various styles of strain accommodation along subduction interfaces from shallow to deep. The ductile-brittle transition at shallower portions of the subduction plate boundary was identified in three tectonic mélange zones (Mugi mélange, Yokonami mélange, and Miyama formation) in the Cretaceous Shimanto Belt, an on-land accretionary complex in southwest Japan. The transition is defined by a change in deformation features from extension veins only in sandstone blocks with ductile matrix deformation (possibly by diffusion-precipitation creep) to shear veins (brittle failure) from shallow to deep. Although mélange fabrics represent distributed simple to sub-simple shear deformation, localized shear veins are commonly accompanied by slickenlines and a mirror surface. Pressure-temperature (P-T) conditions for extension veins in sandstone blocks and for shear veins are distinct on the basis of fluid inclusion analysis. For extension veins, P-T conditions are approximately 125 to 220°C and 80 to 210 MPa. For shear veins, P-T conditions are approximately 185 to 270°C and 110 to 300 MPa. The P-T conditions for shear veins are, on average, higher than those for extension veins. The temperature conditions overlap in the range of approximately 175 to 210°C, which suggests that the change from more ductile to brittle processes occurs over a range of depths.
    [Show full text]
  • Structural Study of the Ogama-Rockland Gold Deposit, Southeastern Margin of the Ross River Pluton, Rice Lake Greenstone Belt, Southeastern Manitoba (NTS 52L14) by X
    ERRATUM Report of Activities 2012 Manitoba Innovation, Energy and Mines Manitoba Geological Survey GS-5 Structural study of the Ogama-Rockland gold deposit, southeastern margin of the Ross River pluton, Rice Lake greenstone belt, southeastern Manitoba (NTS 52L14) by X. Zhou, S. Lin and S.D. Anderson Reprinted with revisions, 2012. The following figure has been revised (page 66): Figure GS-5-5: Outcrop photographs of fault-fill veins in the area of Ogama-Rockland gold deposit: a) thin, laminated quartz vein in a discrete ductile shear zone; b) example of a possible conjugate shear zone and fault-fill vein system. GS-5 Structural study of the Ogama-Rockland gold deposit, southeast- ern margin of the Ross River pluton, Rice Lake greenstone belt, southeastern Manitoba (NTS 52L14) by X. Zhou1, S. Lin1 and S.D. Anderson Zhou, X., Lin, S. and Anderson, S.D. 2012: Structural study of the Ogama-Rockland gold deposit, southeastern margin of the Ross River pluton, Rice Lake greenstone belt, southeastern Manitoba (NTS 52L14); in Report of Activities 2012, Manitoba Innovation, Energy and Mines, Manitoba Geological Survey, p. 59–67. Summary Research and Development grant The Archean Rice Lake greenstone belt is the most from the Natural Sciences and important lode gold district in Manitoba and lies in the Engineering Research Council of Canada in partnership western part of the Uchi Subprovince of the Superior with Bison Gold Resources Inc. and with in-kind support Province. Unlike most gold deposits in the Rice Lake belt, from the Manitoba Geological Survey. which are hosted by layered gabbro sills, basalt flows or In the first field season of what is designed as a three- volcaniclastic rocks, the Ogama-Rockland gold deposit is year mapping project, the first author carried out 1:1000 hosted by granitoid intrusive rocks.
    [Show full text]
  • Slickensides and Slickenlines
    CORRESPONDENCE 319 References Cann, J. R. 1969. Spilites from the Carlsberg Ridge, Indian Ocean. /. Petrology 10,1-19. Chinner, G. A. & Fox, J. S. 1974. The origin of cordierite-anthophyllite rocks in the Land's End aureole. Geol. Mag. Ill, 397-408. Floyd, P. A. 1965. Metasomatic hornfelses of the Land's End aureole at Tater-du, Cornwall. /. Petrology 6, 223-45. Floyd, P. A. 1968. Distribution of Cu in the basic hornfelses of the Land's End aureole, Cornwall and other chemically similar rocks. Geochim. cosmochin. Ada 32, 879-96. Floyd, P. A. & Lees, G. J. 1972. Preliminary petrological and geochemical data on the Cudden Point greenstone. Proc.Ussher Soc. 2, 421-3. Melson, W. G. & van Andel, J. H. 1966. Metamorphism in the Mid-Atlantic Ridge, 22° N. latitude. Marine Geol. 4, 165-86. Melson, W. G., Thompson, G. & van Andel, T. H. 1968. Volcanism and metamorphism the Mid-Atlantic Ridge, 22° N. latitude. /. Geophys Res. 73, 5925-41. Morton, R. D. & Smith, D. G. W. 1971. Differentiation and metasomatism within a Carboniferous spilite-keratophyre suite in S.W. England. Spec. Paper Mineral. Soc. Japan, 1, 127-33. Tilley, C. E. 1935. Metasomatism associated with the greenstone-hornfelses of Kenidjack and Botallack, Cornwall. Mineralog. Mag. 24, 181-202. Vallance, T. G. 1965. On the chemistry of pillow lavas and the origin of spilites. Mineralog. Mag. 34, 471-81. Vallance, T. G. 1967. Mafic rock alteration and isochemical development of some cordierite-anthophyllite rocks. /. Petrology 8, 84-96. Vallance, T. G. 1969. Spilites again: some consequences of the degradation of basalts.
    [Show full text]
  • Fluid History of the Sideling Hill Syncline, Hancock County, Maryland
    FLUID HISTORY OF THE SIDELING HILL SYNCLINE, HANCOCK COUNTY, MARYLAND William J. Lacek A Thesis Submitted to the Graduate College of Bowling Green State University in Partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 2015 Committee: John Farver, Advisor, Charles Onasch, Margaret Yacobucci ii ABSTRACT John Farver, Advisor Fluid inclusion microthermometry was employed to determine the fluid history of the Sideling Hill syncline in Maryland with respect to its deformation history. The syncline is unique in the region in that it preserves the youngest rocks (Mississippian) in the Valley and Ridge Province and is the easternmost exposure of Mississippian rocks in this portion of the Central Appalachians. Two types of fluid inclusions were prominent in vein quartz: CH4-rich and two-phase aqueous with the former comprising about 60% of the inclusions observed. The presence of the two fluids in inclusions that appear to be coeval indicates that the migrating fluid was a CH4- saturated aqueous brine that was trapped immiscibly as separate CH4-rich and two-phase aqueous inclusions. Cross cutting relations show that at least two generations of veins formed during deformation. Similarities in chemistry of the inclusions in the different vein generations suggests that a single fluid was present during deformation. Older veins were found to have formed at depths of at least 5 km while younger veins formed at minimum depths of 9 km. Overburden for older veins is attributed to emplacement of the North Mountain Thrust (NMT) sheet (~6 km thick). The thickness of the Alleghanian clastic wedge is calculated to be ~2.5 km in the Appalachian Plateau which accounts for most of the remaining overburden in younger veins.
    [Show full text]