UBC Undergraduate Research

Structural Setting of Argentiferous Veins, Cariboo Gold District, East-Central British Columbia Gavin, Rachel A. Mar 31, 2017

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
52966-Gavin_Rachel_EOSC_449_Structural_setting_argentiferous_2017.pdf [ 6.03MB ]
Metadata
JSON: 52966-1.0347675.json
JSON-LD: 52966-1.0347675-ld.json
RDF/XML (Pretty): 52966-1.0347675-rdf.xml
RDF/JSON: 52966-1.0347675-rdf.json
Turtle: 52966-1.0347675-turtle.txt
N-Triples: 52966-1.0347675-rdf-ntriples.txt
Original Record: 52966-1.0347675-source.json
Full Text
52966-1.0347675-fulltext.txt
Citation
52966-1.0347675.ris

Full Text

   Structural Setting of Argentiferous Veins, Cariboo Gold District, East-Central British Columbia  by  RACHEL A. GAVIN    A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF  THE REQUIREMENTS FOR THE DEGREE OF  BACHELOR OF SCIENCE (HONOURS)  in  THE FACULTY OF SCIENCE  (Geological Sciences)       This thesis conforms to the required standard   ……………………………………… Supervisor  THE UNIVERSITY OF BRITISH COLUMBIA  (Vancouver)  MARCH 2017    © Rachel A. Gavin, 2017  ii  ABSTRACT  The Cariboo Gold District (CGD) in east-central British Columbia is a hotbed for gold exploration and production. The Cariboo gold rush began in the late 1850s with the discovery of placer-gold in streams near Likely and the Wells-Barkerville area, and lode-gold was discovered not long after. To date, the CGD has yielded an estimated 118 - 134 tonnes of gold (Levson and Giles, 1993). Although structural controls appear to be similar throughout the CGD, not all mineralized veins are gold-bearing. Silver Mine, Penny Creek, and Cariboo Hudson are three veins in a cluster of argentiferous quartz veins, located 23 km southeast of Barkerville Gold Mines’ Cow Mountain deposit; these veins are dominated by silver, copper, lead, zinc and tungsten minerals with little to no gold mineralization. The Silver Mine vein is the best-exposed vein in the cluster and is the focal point of this study.  The Silver Mine vein is a 2 m wide, steeply-dipping, north-northeast striking, fault-filling Ag-W polymetallic quartz-carbonate vein hosted within the Hardscrabble Mountain succession of the Barkerville subterrane. Structural analysis of the Silver Mine and surrounding veins suggest it may be a ‘strike vein’, similar to the B.C. Vein situated 23 km northwest. The Silver Mine vein may have formed by exploiting a preexisting thrust fault and, under sustained northeast-directed regional shortening, gradually rotating and continuously reactivating an area of rheological contrast at a high angle to the inferred direction of maximum regional stress. Relatively fresh lamprophyre dikes, some containing xenoliths of quartz vein fragments, intrude close to and cross-cut the vein at Silver Mine; Ar40/Ar39 geochronology confirms that these intrusions are ~20 Mya younger than the vein.   The Au-Ag-Pb-Zn ± Cu-W tenor of Silver Mine and nearby veins is distinct from the Au ± Pb-Bi tenor of ore in veins in the Wells-Barkerville camp. Many of the Ag-W polymetallic veins are located within, or very near to, the relatively more carbonaceous and fissile Hardscrabble Mountain Succession, whereas Au veins tend to be hosted by the Downey Succession. Host rock lithology may be an important factor in vein ore mineralogy.      iii  TABLE OF CONTENTS  TITLE PAGE ………………………………………………………………………… i ABSTRACT ………………………………………………………………………… ii TABLE OF CONTENTS …………………………………………………………… iii LIST OF FIGURES ………………………………………………………………… v LIST OF TABLES …………………………………………………………………… vi LIST OF PLATES …………………………………………………………………… vii APPENDICES ………………………………………………………………………viii ACKNOWLEDGEMENTS ………………………………………………………… ix 1.0 INTRODUCTION, METHODS, and PREVIOUS WORK 1.1 Introduction ……………………………………………………………… 1 1.2 Methods ………………………………………………………………… 1 1.3 Previous Work …………………………………………………………… 3 2.0 REGIONAL GEOLOGY 2.1 Regional Geologic Setting ……………………………………………… 4 2.2 Regional Deformational History ………………………………………… 7 2.3 Regional Mineralization ………………………………………………… 9 3.0 MAPPING RESULTS 3.1 Physiography …………………………………………………………… 10 3.2 Silver Mine Overview …………………………………………………… 11 3.3 Unit Descriptions ………………………………………………………… 12 3.4 Structural Geology of Study Area ……………………………………… 19  4.0 GEOCHRONOLOGY and SWIR RESULTS 4.1 Short Wave Infrared Spectrometry ……………………………………… 26  4.2 Ar40/Ar39 Geochronology ………………………………………………… 28 5.0 DISCUSSION 5.1 Comparison to Nearby Mineralized Veins ……………………………… 28 5.2 Formation and Mineralization of Strike Veins …………………………… 32  iv  5.3 Genetic Models for Argentiferous Veins ……………………………… 33  6.0 CONCLUSION 6.1 Summary ………………………………………………………………… 34 6.2 Future Work ……………………………………………………………… 36 REFERENCES CITED ……………………………………………………………… 37         v  LIST OF FIGURES  Figure 1. Geologic map of the Barkerville subterrane, British Columbia …………… 5 Figure 2. Schematic stratigraphic column of the Barkerville subterrane, British Columbia ……………………………………………………………………  6 Figure 3. Block model demonstrating possible mechanism for D4 kink  folds formation ……………………………………………………………………… 8 Figure 4. Block model illustrating regional structural model ………………………… 10 Figure 5. Silver Mine outcrop ………………………………………………………… 12 Figure 6. Carbonaceous metapelite ………………………………………………… 13 Figure 7. Micaceous psammite ……………………………………………………… 14  Figure 8. Quartz-carbonate polymetallic vein ……………………………………… 16 Figure 9. Lamprophyre dike ………………………………………………………… 17 Figure 10. Porphyritic diorite dike …………………………………………………… 18  Figure 11. Map of structural data collection localities ……………………………… 20 Figure 12. Stereographic projections for Silver Mine and minor nearby outcrops …… 21 Figure 13. Microphotographs of micaceous psammite with shear indicators ………… 22 Figure 14. Oriented sample RG16-CB10 …………………………………………… 23 Figure 15. Microphotograph of thin section from RG16-CB10 ……………………… 24 Figure 16. Transport and Rotation model for misoriented sinistral shear …………… 25 Figure 17. Lateral escape model for misoriented sinistral shear …………………… 25 Figure 18. C’-type shear band model for misoriented sinistral shear ………………… 26 Figure 19. Regional map showing relative positions of ‘strike veins’ ……………… 30 Figure 20. Photomicrographs demonstrating vein mineralogy ……………………… 31 Figure 21. Regional map showing trends in ore mineral tenor ……………………… 35                   vi  LIST OF TABLES  Table 1. Short Wave Infrared Spectrometry results ………………………………… 27  Table 2. Preliminary Ar40/Ar39 ages for selected samples …………………………… 28 Table 3. Summary of Ag-bearing vein ore mineralogy and ages …………………… 29     vii  LIST OF PLATES  Plate 1: Geologic map of the Silver Mine study area (back pocket)       viii  APPENDICES  Appendix A. Samples database ……………………………………………………… 39 Appendix B. Ar-Ar data ……………………………………………………………… 47 Appendix C. Short Wave Infrared Spectrometry data ……………………………… 55 Appendix D. Digital appendix including: 1) Field photographs 2) Rock photographs 3) Scanned thin sections 4) Thin section photomicrographs 5) GIS shapefiles 6) Original figures and maps (.ai and .pdf files)   Attached at the back of this thesis.        ix  ACKNOWLEDGEMENTS    This project has been an incredible learning experience, and it would not have been possible without the support of several key people. I am thankful for Barkerville Gold Mines Ltd. for putting me up in their regional exploration camp for the duration of my fieldwork and for providing logistical and technical support. I would especially like to thank Terence Harbort, who was instrumental in the conception of this project.  I would like to express my gratitude to Sara Jenkins for her expert GIS advice, and to Barry Penner, who was always willing to spare some time for thin section suggestions and for general words of wisdom. I would also like to thank Geoscience BC and the Society of Economic Geologists Canada Foundation for their generous financial support to make this project happen.  Last, but not least, I would like to thank my supervisor, Murray Allan. His guidance and inspiration both in and out of the field have been fundamental not only in the completion of this thesis, but also to my overall academic growth.        1  1.0  INTRODUCTION, METHODS, and PREVIOUS WORK   1.1  Introduction  The Cariboo Gold District (CGD) in east-central British Columbia is a hotbed for gold exploration and production. The Cariboo gold rush began in the late 1850s with the discovery of placer-gold in streams near Likely and the Wells-Barkerville area, and lode-gold and sulfide replacement style mineralization was discovered not long after. To date, the CGD has yielded an estimated 118 - 134 tonnes of gold (Levson and Giles, 1993).  Mineralized veins in the CGD are broadly classified as ‘orogenic’. These dominantly quartz-carbonate veins are approximately coeval, and share similar structural controls; however, not all mineralized veins are gold-bearing. Silver Mine, Penny Creek, and Cariboo Hudson are three occurrences with mineralized veins in a cluster of dominantly argentiferous quartz veins, located 23 km southeast of Barkerville Gold Mines’ Cow Mountain deposit; these veins are dominated by silver, copper, lead, zinc and tungsten minerals with little to no gold mineralization. The Silver Mine vein is the best-exposed vein in the cluster and although it is the focal point of this report, Penny Creek veins and other localities in between are also studied. Data and conclusions in this report are a result of mapping, structural analysis, and Ar40/Ar39 geochronology, the main goal being to characterize the geology and structural setting of argentiferous veins in the Cariboo Gold District.    1.2  Methods  Fieldwork  Fieldwork for this project was completed in the summer of 2016 during a visit to Barkerville Gold Mines’ regional exploration camp near Wells, BC. Outcrop mapping of the  2  Silver Mine adit and upper pit area was carried out on August 20th and 21st. Maps were made at 1:100 scale and were scanned, georeferenced and digitized using ArcMap 10.4 software. The objective of mapping was to record relationships between units, structure, and shear sense indicators.  34 rock samples were collected in situ, from float, or from mine waste piles. Thin sections were made from 21 of these samples; 11 samples were selected for Short Wave Infrared Spectrometry; and hydrothermal muscovite and primary biotite from quartz veins and lamprophyres, respectively, were submitted for Ar40/Ar39 geochronology.  Petrography  Billets were cut on saws at UBC and sent to Vancouver Petrographics for thin section preparation. In total, 32 polished thin sections, eight of which are from oriented samples, were made for both reflected and transmitted light microscopy. Oriented thin sections were cut perpendicular to foliations and parallel to lineations to highlight shear sense indicators such as rotated pyrite porphyroblasts. All thin sections were scanned in both Plane Polarized and Cross Polarized Light for reference. Thin sections were observed on a Nikon Eclipse E600 POL polarizing microscope. A dedicated Canon Rebel EOS T21 digital SLR camera mounted on the microscope was used to capture photomicrographs of various scales.  Ar-Ar Geochronology  Two vein samples and two lamprophyre samples were selected for Ar40/Ar39 geochronology. Grains of coarse, hydrothermal muscovite from quartz vein samples and grains of primary biotite from lamprophyre dikes were hand-picked by Murray Allan at UBC and submitted to Dr. Alfredo Camacho at the University of Manitoba for Ar-Ar analysis.     3  Short-Wave Infrared Spectrometry  Eleven hand samples were selected for spectral analysis to aid in determining mineralogy of both host rock and vein material. Host rock samples containing lightly coloured sheet silicates and/or carbonates, and vein samples containing carbonates and/or scheelite were analyzed. Spectral data was collected with a Terraspec using RS3 spectral acquisition software. Spectra were subsequently compared with a library of reference mineral spectra to determine most likely mineralogy using TSG pro software.   1.3  Previous Work  A 180 ft adit was driven along the polymetallic quartz-carbonate vein at Silver Mine in 1980, and production continued for one year (Termuende, 1990). In 1989, the Silver Mine claim was optioned from Chaput Logging by Loki Gold. Between the months of May and November of that year, Loki Gold did field work on many claims in the Craze Creek / Cunningham Creek property, Silver Mine included. Smaller-scale mapping (1:5000) was completed over the entire property, while trenching, larger-scale mapping (1:100 and 1:1000) and soil geochemistry was done at Silver Mine. Diamond drilling was done at other claims on the property, but not at Silver Mine (Termuende, 1990). In 1995, a report by Norian Resources Corp. recommended three diamond drillholes at Silver Mine to determine structure and grade (Blann, 1995), however, no drilling has taken place at the showing.   Barkerville Gold Mines Ltd. currently owns continuous mineral rights to much of the Cariboo Gold belt. They are conducting a multi-year regional soil sampling and prospecting project, as well as airborne magnetics and VTEM surveys. This data is not yet publicly available.       4  2.0  REGIONAL GEOLOGY   2.1  Regional Geologic Setting  The Cariboo Gold District (CGD) is a 60 km-long, north-northwest trending belt of orogenic lode gold and placer gold mineralization in east-central British Columbia (Fig. 1). The town of Wells and the historic town of Barkerville are near the northwestern end of the district, and Cariboo Lake is near the southeastern end. The CGD spans four terranes: Barkerville, Cariboo, Quesnel, and Slide Mountain. The Barkerville subterrane represents the northernmost part of the Kootenay terrane, and is in fault contact with the Cariboo terrane to the east, separated by the east-dipping Pleasant Valley thrust fault (Struik, 1988). The Cariboo terrane is structurally overlain by the Slide Mountain terrane, separated by the gently-dipping Pundata thrust fault. Part of the Slide Mountain terrane also overlaps the eastern edge of the Barkerville subterrane, northwest of Wells (Schiarizza and Ferri, 2003). On its western flank, the Barkerville subterrane is bound by the predominantly arc-derived sedimentary, volcanic and intrusive rocks of the Quesnel terrane (Struik, 1988). The two terranes are separated by the west-dipping Eureka thrust fault.  According to Schiarizza and Ferri (2003) the relationship between Barkerville, Cariboo, and Slide Mountain terranes could be interpreted to reflect early emplacement of the Antler allochthon of Slide Mountain terrane above Cariboo terrane, followed by west-directed thrusting of Cariboo above Barkerville subterrane. An alternate interpretation is that Cariboo was thrust upon Barkerville prior to emplacement of the Antler allochthon (Struik, 1986). Mappable units within the Barkerville subterrane repeat across-strike, supporting the interpretation that the map pattern is the surface expression of a major southwest-verging nappe structure, which is itself folded by the northwest trending Lightning Creek antiform (Fig. 1).  5   Figure 1. Simplified geologic map of the Cariboo Gold District. Cross-sections A through D demonstrate an inferred refolded nappe structure. Upright fold along the Lightning Creek antiform is open to the northwest, and tight to the southeast (Adapted from Schiarizza and Ferri, 2002).  The Barkerville subterrane comprises mainly the Snowshoe Group: these predominantly siliciclastic rocks of Proterozoic to Paleozoic age are interpreted as an outboard facies likely to represent the edge of ancestral North America (Ferri and Schiarizza, 2006; Struik, 1988). There has been much debate about the stratigraphy of the Snowshoe Group; the stratigraphy originally defined and mapped by Struik (e.g. 1988) has been reinterpreted by Ferri and Schiarizza (2003, 2006) based on regional correlations of units with Kootenay terrane rocks in southern British Columbia. According to this most recent reinterpretation, the Snowshoe Group comprises three main compositional packages (Fig. 2), from oldest to youngest:      6  Downey succession: greenish-grey, micaceous quartzite or feldspathic quartzite, phyllite or schist, locally with a distinctive orthoquartzite at the top of the sequence;  Harveys Ridge succession: dark grey to black phyllite, siltstone, quartzite with light grey quartzite and feldspathic quartzite becoming more abundant up section; Goose Peak succession: light grey to light greenish grey quartzite to feldspathic quartzite with interbedded dark grey phyllite and siltstone.     Figure 2. Stratigraphic column of the Snowshoe Group (Adapted from Ferri and Schiarizza, 2006). The Silver Mine vein lies within the Hardscrabble/Harveys ridge package.  A cluster of argentiferous veins is situated near the western edge of the Barkerville subterrane (Study area, Fig. 1), within the Hardscrabble Mountain facies of the Harveys Ridge succession; the Silver Mine vein is the largest, most well-exposed vein in the cluster.    7  2.2  Regional Deformational History  At least two distinct syn- to post-accretionary phases of deformation have been recorded in the Cariboo Gold Belt. Phase one (D1) and phase two (D2) of deformation are thought to have occurred in response to eastward obduction of Nicola Group rocks of the Quesnel terrane onto the Barkerville terrane during the late Early Jurassic to mid-Middle Jurassic (Ferri and Schiarizza, 2006). The fabric produced by phase 1 and phase 2 of regional deformation is intense and overprints evidence for an earlier, pre-accretionary phase of deformation except locally. The phases are outlined below: D1 deformation: This event produced a penetrative, bedding sub-parallel slaty to phyllitic flattening cleavage (S1), that is axial planar to minor isoclinal F1 folds (Rhys and Ross, 2001). Bedding is commonly transposed along S1. Significant, ductile, penetrative shortening is recorded in D1 (Rhys and Ross, 2009). D2 deformation: This event produced a spaced to penetrative northeast-dipping foliation (S2), axial planar to northwest-trending folds and crenulations (Rhys and Ross, 2001). Shallowly plunging, northwest and southeast trending L-S tectonites (defined by mineral stretching lineation L2) result from the intersection between S1 and S2 (Allan, 2017). These L2 features are parallel to axes of F2 folds. F2 folds form the regional recumbent, southwest-verging nappe structures interpreted by Ferri and Schiarizza (2006). Peak metamorphic minerals define S2, suggesting that peak metamorphism occurred during D2 (Rhys and Ross, 2001) D3 deformation: Phyllosilicate-rich units record a spaced, northwest trending, steeply dipping crenulation cleavage (S3). L3 lineations are easily distinguished from L2 lineations because they lack rodding and elongation. D3 deformation produced the Lightning Creek Anticline, a major, northwest trending, open, upright antiform (Rhys and Ross, 2001). D4 deformation: Locally, a fourth phase of deformation is manifested in phyllosilicate-rich rocks as northeast trending kink folds (Rhys and Ross, 2001). These folds may have formed during lateral extrusion against a competent ‘backstop’ (Fig. 3).   8   Figure 3. Block model demonstrating possible mechanism for D4 kink fold formation. Less competent layers (dark grey) are extruded laterally toward the northwest as a result of compression in the southeast; a competent ‘backstop’ initiates a localized compression direction (σ1) parallel to extruding direction, causing less competent layers to buckle and kink (adapted from Allan, 2017).   Structurally late faulting in the CGD is dominated by north- to northeast trending, moderate- to steeply dipping dextral faults that offset lithological boundaries and earlier thrust surfaces (Rhys and Ross, 2009). These predominantly brittle faults displace F2 folds, thus were likely not active prior to D2 deformation (Rhys and Ross, 2001). Importantly, these faults are commonly spatially associated with gold-bearing quartz veins (Mortensen et al., 2011).      9  2.3  Regional Mineralization   Both replacement style mineralization and quartz vein mineralization are prevalent in the CGD; for the purpose of this study, only quartz vein mineralization will be described. Three types of quartz veins are associated with mineralization (Fig. 4), and are outlined below: Diagonal veins: Diagonal veins are east trending, steeply dipping sinistral shear veins that extend 20 - 150 m along strike (Rhys et al., 2009). These veins are cut by north-trending, moderately- to steeply east-dipping, late-D2 faults and associated fault-filling veins. Despite the cross-cutting relationships between the easterly-trending and northerly-trending veins, they are kinematically consistent with a Riedel shear model with northeast-directed shortening. Transverse veins: Transverse veins are coeval with diagonal veins. These are northeast trending extensional veins (Rhys et al., 2009), forming sheeted sets parallel to the direction of greatest stress (σ1). Quartz and/or carbonate in these veins commonly exhibit comb textures, where fibers parallel the opening direction of the veins. These veins are generally orthogonal to L2 lineations, also supporting formation during late D2.  Strike veins: While relatively less common, these veins are the most continuous along strike. These veins strike roughly north-northwest and dip steeply to the northeast, and are parallel or sub-parallel to lithology. These veins are similar to older, barren veins, but mineralized strike veins are less deformed, likely having formed during late D2 (Rhys and Ross, 2001). The BC vein, 3 km southeast of Wells, BC, is the largest and most prominent example of a strike vein. Hosted by the BC fault system, it is steeply northeast-dipping, and extends at least 800 m along strike (Rhys and Ross, 2001). The formation of strike veins is discussed further in section 5.2.    10   Figure 4. Block model illustrating relationships between dextral and sinistral shear veins, extensional veins, and ‘strike’ veins (e.g. B.C. vein and possibly Silver Mine vein). Strike veins are at a high angle to the inferred σ1 direction, striking northwest and dipping steeply toward the northeast, and are approximately parallel to foliations (adapted from Allan, 2017).   3.0  MAPPING RESULTS    3.1  Physiography   The Cariboo was most recently glaciated during the Late Wisconsinan Fraser Glaciation (Levson and Giles, 1993). Ice from the Coast Mountains and the Cariboo Mountains flowed generally toward the northeast and northwest, respectively, with the flow coalescing in the vicinity of the Fraser River and diverting toward the north. During deglaciation ice movement was increasingly topographically controlled, retreating in valleys and eventually breaking up and wasting away (Tipper, 1971).  The Cariboo Gold Belt occupies a region of moderate topographic relief. Quesnel Lake, a topographic low point situated roughly in the middle of the belt, has an approximate     11  surface elevation of 700 m; the peaks of Cow Mountain, Roundtop Mountain, and Spanish Mountain (as local examples) reach elevations of 1780 m, 2400 m, 1580 m respectively. Vegetation is abundant, with deciduous and evergreen trees, shrubs, and low-lying greenery. Rock exposure is generally limited, however, an extensive network of service roads (maintained by logging companies and placer claimholders) gives access to numerous roadcut outcrops. Small-scale historic mine workings such as Silver Mine and Penny Creek, also provide reasonable exposure, and some outcrops are very well-exposed along streams.   3.2  Silver Mine Overview  The Silver Mine is situated at roughly 52°54'28"N, 121°19'55"W, approximately 23 km southwest of Barkerville Gold Mines’ Cow Mountain deposit. From Wells, the site is accessed via the Cunningham Pass forest service road (3100 road) and the Keithley Creek - Barkerville forest service road that branches south off the 3100 road near the 14-km mark. A spur road branches off to the north 14 km down the Keithley Creek - Barkerville road, about 1 km after bending to the east and just before a sharp bend to the southwest where the road crosses Penny Creek. The collapsed adit of Silver Mine’s main exposure is approximately 200m along this spur road, after it diverts uphill to the west, at 5000 ft elevation. The main rock exposure of Silver Mine is a weathered roadside outcrop approximately 50 m long and 10 m high (Fig. 5). The outcrop is weathered and scruffy, especially in the carbonaceous metapelite exposed west of the vein. Foliations are generally steeply dipping toward the northeast, and the vein is roughly parallel to these foliations.  An additional exposure lies 40 m to the north-northwest at approximately 5100 ft elevation. The vein is visible in cross-section at this outcrop as a result of previous mining activities, and it is less weathered than at the lower level. This segment of vein is interpreted to be the along-strike continuation of the vein at the adit level, however, the area between the two exposures is covered with mine waste, colluvium, and dense vegetation so it cannot be traced with certainty.    12   Figure 5. Outcrop at Silver Mine. (I) Outcrop at Silver Mine adit level, 5000 ft elevation, facing north-northwest. (II) Outcrop at Silver Mine upper pit, 5100 ft elevation, facing north-northwest. Units are labelled as follows: (A) Carbonaceous metapelite; (B) Quartz-carbonate polymetallic vein; and (C) Micaceous psammite.  Geological units were inferred between lower and upper outcrops; the vein exposed at the upper level appears to be a continuation along strike of the exposure at the adit level. Structural data were collected and is discussed in section 2.5.     3.3  Unit Descriptions  Carbonaceous Metapelite  Brownish to rusty-orange weathered, fissile to flaggy, dark grey to black metapelite (Fig. 6) occupies the west side (foot wall) of the vein. This unit is variably silicified, with stronger silicification proximal to the diorite dike. Dark grey to black, carbonaceous, fine-grained platy minerals define an undulating, irregular foliation that gives this unit its characteristic colour. Less silicified foliation surfaces have a greasy lustre, but elsewhere the rock is dull to earthy. Variably sized (< 1 mm up to cm scale) foliform quartz veins are abundant, and thinner (1-3 mm wide) quartz veins locally cross-cut the main foliation. Fine-  13  to coarse-grained, subhedral sigmoidal pyrite porphyroblasts are sparsely dispersed throughout the unit. Proximal to the vein, these sigmoidal clasts are clockwise-rotated, indicating a dextral shear sense parallel to the vein.    Figure 6. Carbonaceous metapelite; clockwise from left: 1) Outcrop; knife is placed on the contact with the diorite dike on the far left. This is a relatively more silicified portion of the metapelite, possibly altered as a result of intrusion of the dike. Orange-brown limonite, a weathering product of iron, locally forms layers over the rock. 2) RG16-CB11c (B) (PPL), scanned thin section showing highly deformed and silicified carbonaceous metapelite. Opaque minerals are predominantly carbonaceous platy minerals, however, some pyrite is also present. 3) RG16-CB29 (PPL) less silicified, relatively undeformed carbonaceous metapelite. 2) and 3) represent approximate end-members of the variably silicified and deformed unit.  Micaceous Psammite  Orange to rusty-brown weathered, fissile to flaggy, fine grained, greenish-grey mica-rich psammite (Fig. 7) occupies the east side (hanging wall) of the vein. Light coloured micas define foliations, and foliation surfaces have a silvery sheen. Fine-grained (up to 1 mm), euhedral to subhedral pyrite is abundant and clustered along foliations.    14   Figure 7. Micaceous psammite; Clockwise from left: 1) Outcrop, showing weathering pattern and fissile cleavage. Oriented sample on sample bag is RG16-CB09. 2) RG16-CB07 (PPL), scanned thin section showing foliations defined by alternating light- and dark-coloured micas and other platy minerals, and extensional quartz-carbonate veinlets cutting S0/S1 foliations at a high angle. Euhedral quartz grains form vein walls while large undeformed carbonate fills centres. Opaque minerals are euhedral pyrite, which overprint foliations. 3) RG16-CB09 (PPL), scanned thin section showing typical foliations and gentle drag folds near fractures. Opaque minerals are euhedral pyrite, which overprint foliations.  Proximal to the main vein, this rock is cut by chaotically oriented quartz or quartz-carbonate veinlets. Most of the larger (~ 1 cm wide) veinlets are milky white extensional quartz-carbonate veins, tapering to pointed tips. Some of these veinlets are sparsely mineralized with tetrahedrite and galena. Narrower veinlets (~ 1 mm wide) are glassier and are mineralized with small amounts of pyrite. Coarse-grained (~ 2 mm) euhedral pyrite is concentrated proximal to veinlets and overprints the S0/S1 foliation. Locally, the S0/S1 foliation envelops 1-3 mm ferroan carbonate porphyroblasts, which weather to a rusty brown colour.  Sigmoidal and deltoidal pyrite porphyroclasts are clockwise-rotated proximal to the vein, giving a dextral sense of movement along the vein.    15  Quartz-Carbonate Polymetallic Vein  The main vein is a 1 - 2 m wide quartz-carbonate vein (Fig. 8). The vein is zoned parallel to vein walls giving it a layered appearance, with layers defined by alternating creamy white barren quartz-carbonate material and darker mineralized material. Ore minerals include (in order of decreasing abundance): ● Galena: interstitial (between quartz grains) to blebby, intergrown with tetrahedrite; ● Sphalerite: dark brown, occurring as discrete coarse subhedral to anhedral grains or intergrown with galena and tetrahedrite; ● Tetrahedrite: interstitial (between quartz grains) to blebby, intergrown with tetrahedrite or filling cleavages in galena; ● Scheelite: creamy white to light orange, occurring as discrete patches within quartz-carbonate gangue; ● Arsenopyrite (trace): yellowish-silver, disseminated grains. Locally the vein is stained green and blue by malachite and azurite, respectively, which are weathering products associated with tetrahedrite. Scheelite and arsenopyrite were relatively more abundant in samples collected from a waste pile in Penny Creek.   Lamprophyre Dike  Relatively fresh, brown to rusty-brown, spheroidal-weathering, approximately 1 m wide lamprophyre dike (Fig. 9) appears to cross-cut S0/S1 fabric of carbonaceous metapelite and micaceous psammite, as well as the main vein. The unit is mildly porphyritic; larger phenocrysts are colourless (PPL), subhedral- to euhedral, high relief and high birefringence, and are partially chloritized at their edges. The bodies of the phenocrysts are likely altered as well, possibly to clay minerals. Subhedral biotite phenocrysts are fresher and abundant.  16   Figure 8. Quartz-carbonate polymetallic vein: (I) Outcrop at upper pit of Silver Mine (facing north); notebook for scale. In subsequent images, Mlc = malachite, Ttr = tetrahedrite, Gn = galena, Sp = sphalerite, Sch = scheelite. (II) Hand sample showing zoning on weathered surface (top) and cut surface (bottom); knife for scale. (III) Hand sample showing zoning and comb textured quartz-carbonate gangue on bottom left. (IV) Hand sample showing patches of scheelite and interstitial galena; knife for scale.    17  The groundmass comprises mainly elongated, needle-like feldspar, in some places grown in radiating patterns filling in what may have been miarolitic cavities in the cooling and degassing magma. The lamprophyre is cut by narrow (< 1 mm) carbonate-pyrite extensional veins, with fibers paralleling opening direction.   Figure 9. Lamprophyre dike: (I) Outcrop, above upper pit at Silver Mine (facing north); hammer for scale. Note spheroidal weathering of the dike, and how the dike itself protrudes. (II) Photomicrograph (10x, 2mm FOV) showing characteristic subhedral phenocryst partly altered to chlorite. Dark green-brown, smaller phenocrysts are likely hornblende, and groundmass is predominantly plagioclase; opaque minerals are pyrite. (III) Hand sample, showing cut surface. (IV) Photomicrograph (5x, 4mm FOV) showing radiating needle-like plagioclase and biotite filling in a miarolitic cavity; opaque minerals are pyrite.  Porphyritic Diorite Dike  Highly altered, massive intermediate porphyritic dike, roughly parallel to the quartz-carbonate vein (Fig. 10). Brown to rusty brown weathered, with some lighter orange-brown limonite. Fresh surfaces expose a medium-grey groundmass and abundant 1-2 mm wide  18  euhedral- to subhedral dark green-grey phenocrysts (possibly amphibole) and pervasive pyrite alteration. Most of the phenocrysts are completely altered to a black opaque mineral. Several very thin (< 1 mm) quartz veinlets cut the dike in random orientations. Most phenocrysts are almost entirely altered to an opaque black mineral, but in some less altered phenocrysts, 2nd order birefringence is observed. The groundmass appears patchy, with blobby areas of greenish brown clay (?) alteration taking over fresher microcrystalline feldspar and quartz.   Figure 10. Porphyritic diorite dike; clockwise from left: 1) In outcrop facing north-northwest. Dike is in contact with carbonaceous metapelite (knife is approximately over contact). 2) RG16-CB02 (PPL), photomicrograph showing clusters of white, elongated grains within an extensively pyrite-altered groundmass. Phenocrysts are altered to carbonate(?) minerals (upper 3rd order, pearly birefringence). Disseminated opaque (black) mineral is pyrite. 3) RG16-CB02 (PPL), photomicrograph showing cross-cutting carbonate veins and variably altered phenocrysts. Euhedral, six-sided phenocrysts are extensively altered to unknown opaque (black) mineral.       19  3.4  Structural Geology of Study Area  The main vein at Silver Mine is a steeply northeast dipping, north-northwest striking fault-filling vein, separating the carbonaceous metapelite to the west and the micaceous psammite to the east. On the west side of the vein, foliations are dominantly steeply north-northeast-dipping and on the east side foliations are deflected to the northeast; this shift in strike of foliations as well as abrupt change in lithology is indicative of a fault-filling vein. The deflection of foliations could be explained by drag during dextral movement along the fault, rotating foliations in less competent rocks (e.g. carbonaceous metapelite) towards the shear plane. CS-like fabrics at outcrop scale in carbonaceous metapelites west of the vein also suggest a dextral sense of movement along the vein. Structural data was collected at Silver Mine, Penny Creek, and several minor outcrops nearby (Fig. 11). Data was plotted on stereonets (Fig. 12) in order to compare orientations of features with the regional structural model developed near the Wells-Barkerville area (Rhys, 2009) and recently applied regionally by Murray Allan (Fig. 4). Oriented thin sections from micaceous psammite and carbonaceous metapelite were examined for microstructures to support field interpretations. Details for each are described below: Micaceous Psammite (RG16-CB26): In the micaceous psammite unit east of the vein, a thin section oriented approximately parallel to the kinematic plane shows numerous shear sense indicators (Fig. 13). Deltoidal pyrite porphyroblasts have top-to-the-right and bottom-to-the-left tails, resulting from clockwise rotation along foliation planes. Quartz veinlets subparallel to foliations are asymmetrically boudinaged, and dextrally offset. Larger quartz grains show undulose extinction in crossed polars, and are elongated parallel to foliations. Late extensional carbonate veins cut the rock nearly orthogonal to foliations, and fibrous carbonate material grows perpendicular to vein walls during opening.   20   Figure 11. Map showing relative positions of localities where structural data was collected for this study (green circles). BC Minfile locations are shown as white stars.   All the shear sense indicators in this thin section are relatively reliable and all support dextral shear. The trace of extensional veins on one thin section (RG16-CB26 ts 2, fig. 13) is approximately northeast trending, consistent with the regional structural model under northeast-directed shortening. No evidence for vertical motion was found in this sample.  21   Figure 12. Stereographic projections for Silver Mine and minor nearby outcrops. Data is a combination of measurements taken by Rachel Gavin and Murray Allan. (I) Bedding parallel cleavage (S0/S1) is steeply dipping to subvertical, striking northwest; (II) Stretching/mineral elongation lineations (L2) are parallel to σ3; (III) Dextral strike-slip faults are steeply dipping to subvertical, striking north; (IV) Northerly-striking shear veins show dextral sense of movement while easterly-striking shear veins show sinistral sense of movement; (V) Extensional veins are subvertical and northeast-striking, parallel to σ1; (VI) All veins. Red: extensional veins; black: shear veins; bold black: shear veins measured at Silver Mine. The veins at Silver Mine are more westerly-striking than other nearby dextral shear veins.     22  Figure 13. Scanned oriented thin section (PPL and XPL) showing dextral shear sense indicators. Black boxes indicate field of view of higher magnification photomicrographs A and B; (A) Photomicrograph (5x magnification, PPL) showing asymmetrically boudinaged veinlet (diagonal across left side of photo) and clockwise-rotated δ-type pyrite porphyroblasts. (B) Photomicrograph (5x magnification, PPL) showing late extensional carbonate veinlet cutting S0/S1 fabric and an older, relatively undeformed foliform carbonate vein at a high angle. Inset shows fibrous carbonate texture curving to track opening direction of vein.   Carbonaceous metapelite (RG16-CB10): From the carbonaceous metapelite, an oriented sample was taken from the immediate footwall of the vein (Fig. 14). Shear fabrics from this thin section show a sinistral sense of movement (Fig. 15). Given the orientation of the thin section, a sinistral shear sense does not fit nicely with the regional structural model; with northeast- to east-northeast shortening, we would expect sinistral shear features to trend approximately east-west. Three possible mechanisms for misalignment of sinistral features in carbonaceous metapelite proximal to the vein are offered below.    23   Figure 14. Sequence showing process of collecting oriented sample RG16-CB10. (I) Oriented sample replaced on outcrop. Blue dashed line indicates contact between carbonaceous metapelite (west side) and vein (east side). Facing roughly northwest. (II) Oriented, uncut hand sample. (III) First cut, parallel to lineations and approximately perpendicular to foliations. Epoxy was utilized to hold fragile rock together. (IV) Left: to be submitted for thin section. Right: reference sample; thin section is looking at this plane.    24   Figure 15. Scanned oriented thin section from immediate footwall of main vein. Compositional layering S0/S1 is delineated by dashed blue line; Axial-planar cleavage S2 is delineated by dot-dashed green line; Examples of sinistral shear features are denoted with blue arrows.  The carbonaceous metapelites are highly deformable and incompetent. With progressive deformation, shear features that initially formed in an east-west orientation may move and rotate (Fig. 16). Similar effects are seen in originally northeast-trending extensional veins that are rotated near shear zones. S0/S1 fabrics are rotated clockwise on the west side of the vein. Together, these features are permissive of a transport/rotation model.   Alternatively, the vein may be extending to the north-northwest and south-southeast (assuming the vein is ~orthogonal to σ1). Frictional shear due to the extension of the vein could cause ductile wall rock material to flow along with the vein to accommodate stretching (Fig. 17). Carbonaceous metapelite, being relatively less competent than the micaceous psammite on the opposing side of the vein, would be more likely to flow in a ductile fashion. At any given interface between vein and host rock, local dextral or local sinistral movement could result. Vein extension is also seen in the BC vein, an extensively boudinaged vein structurally similar to Silver Mine (similarities discussed further in section 5.1).  25  Figure 16. Transport and Rotation model with east-northeast directed shortening. Sinistral and dextral features are in blue and red, respectively; the vein is in grey. Sinistral shear features form in an approximately east-west direction (solid lines) and are transported and rotated (dashed lines) proximal to the vein. Inset: S0/S1 foliations are approximately parallel to the vein post-rotation, and still show sinistral shear.  Figure 17. Lateral escape model with east-northeast directed shortening.  Sinistral and dextral features are in blue and red, respectively; the vein is in grey. With progressive deformation, the vein may extend perpendicular to the direction of σ1. Ductile wall material, like the carbonaceous metapelites (solid lines), flow north-northeast or south-southeast to accommodate along-strike extension of the vein. Frictional shear along the vein/wall interface results in either local dextral or local sinistral shear.  This effect would be less noticeable or absent in the relatively more competent micaceous psammite east of the vein (dashed lines).      26  One other possible interpretation of these sinistral fabrics is that they are C’-type shear fabrics resulting from progressive dextral ductile shear, causing CS fabrics to rotate into the shear zone boundary (Fig. 18). Stereographic analysis combined with microstructure analysis support the interpretation that the vein at Silver Mine is a dextral, fault-filling shear vein. However, the Silver Mine vein strikes more to the north-northwest, while other dextral shear veins strike north- to north-northeast.    Figure 18. Thin section reference sample showing interpreted C’ shear band. (I) Progressive deformation in a dextral shear zone causes foliations to rotate parallel to shear zone boundary (adapted from Passchier and Trouw, 1996). (II) Blue dot-dashed lines are interpreted S fabrics; magenta dashed lines are interpreted C’ fabrics; red dashed line is shear zone boundary. Light grey vein material at the top of sample is subparallel to main vein.    4.0  GEOCHRONOLOGY AND SWIR RESULTS   4.1  Short Wave Infrared Spectrometry   Short Wave Infrared Spectrometry (SWIR) is a type of reflectance spectroscopy that uses the short-wave infrared (1.3 - 2.5 µm) wavelength regions of the electromagnetic spectrum to analyze minerals. Certain mineral bonds (for example OH, H2O, and CO3) have distinct reflectance signatures which can be useful tools for mineral identification. SWIR does not work well with darker coloured rocks and minerals, because they are less reflective.   27  The most important absorption features for this study are OH/H2O (~1400 nm), molecular water (~1900 nm), Al-OH bonds (~2200 nm), and CO3 (~2300 nm). Absorption features show up as dips in spectra. Muscovite, for example, contains OH and Al-OH, resulting in major dips at around ~1400 nm and ~2200 nm in its spectrum.  TSG pro software automatically compares collected spectra with a library of reference spectra to determine most likely mineralogy; results are summarized in Table 1. Spectra collected are not easily interpreted by eye, since samples contain more than one mineral. Absorption features from multiple minerals present in a sample interfere with each other and obscure spectral features that may be obvious in spectra from pure mineral specimens.   Sample Rock Type Mineral 1 Mineral 2 RG16-CB01 diorite dike Aspectral NULL RG16-CB01 diorite dike Aspectral NULL RG16-CB07 phyllitic psammite Muscovite Ankerite RG16-CB08 phyllitic psammite IntChlorite Muscovite RG16-CB08 phyllitic psammite IntChlorite Muscovite RG16-CB08 phyllitic psammite Muscovite IntChlorite RG16-CB09 phyllitic psammite Muscovite NULL RG16-CB10 carbonaceous metapelite Dark NULL RG16-CB19 vein Dolomite NULL RG16-CB20 vein Illite NULL RG16-CB21 vein Dolomite NULL RG16-CB21 vein Calcite NULL RG16-CB26 phyllitic psammite Muscovite NULL RG16-CB26 phyllitic psammite Muscovite Ankerite RG16-CB26 phyllitic psammite Muscovite NULL RG16-CB27 carbonaceous metapelite Aspectral NULL RG16-CB29 carbonaceous metapelite Aspectral NULL  Table 1. Summary of results from Short-Wave Infrared Spectrometry on 11 samples. Some rocks, such as the carbonaceous metapelite and the diorite dike, are too dark to be analysed by the TerraSpec instrument and give a null result; these samples are greyed out. Phyllitic psammite: light-coloured phyllosilicates in these samples is most likely muscovite. Some intermediate chlorite is also present. Ankerite may be an alteration product, or may be within a carbonate veinlet. Vein samples: carbonates present are dolomite and calcite, with illite possibly as an alteration product.    28  4.2  Ar40/Ar39 Geochronology   Four samples were processed for Ar40/Ar39 ages; preliminary data is presented in this section (Table 2). Hydrothermal muscovite from Penny Creek and Silver Mine give ages of ~ 136-141 Ma and ~ 135-138 Ma, respectively. Ar40/Ar39 ages were obtained for two nearby auriferous vein showings along Cunningham Creek, namely Hibernian and Jewellery Shop, by Mortensen et al., 2011; Hibernian was dated at 137.4 ± 1.6 Ma and Jewellery Shop was dated at 141.0 ± 1.6 Ma.   Ar40/Ar39 geochronology of primary biotite from two lamprophyre samples near Silver Mine gave ages of ~ 110-115 Ma. As the lamprophyre at Silver Mine appears to be at least 20 m.y. younger than the vein, there is likely no genetic link between lamprophyre magmatism and mineralization at Silver Mine.    Sample ID Rock Type and Location Interpreted Ar40/Ar39 Age (Ma) (i) MA16-CB15 Hydrothermal muscovite from vein; Silver Mine 135 - 138 (ii) MA16-CB21 Hydrothermal muscovite from vein; Penny Creek 136 - 141 (iii) RG16-CB03 Primary biotite from lamprophyre; float at Silver Mine 113 - 115 (iv) RG16-CB06a Primary biotite from lamprophyre; in situ at Silver Mine 110 - 115  Table 2. Summary of preliminary Ar40/Ar39 geochronology results from study area (Allan, pers. comm., 2017).    5.0  DISCUSSION   5.1  Comparison to Nearby Mineralized Veins  The vein at Silver Mine is approximately in the same northwest-striking orientation as the BC vein, and is also along strike with the BC vein itself (Fig. 19). Both veins occupy a fault contact between two lithologies and are semi-concordant with stratigraphy. The BC vein defines the boundary between a black carbonaceous phyllite to the west and a variably  29  chloritic/sericitic/dolomitic phyllite to the east, similar to the lithologies on either side of Silver Mine. Both veins show a dextral sense of movement (Rhys and Ross, 2001) and in the case of the BC vein, a reverse, east-side-up component of movement. Details on the formation of strike veins are found in section 5.2 below. The Au-Ag-Pb-Zn ± Cu-W tenor of Silver Mine and nearby veins is distinct from the Au ± Pb-Bi tenor of ore in the Wells-Barkerville camp. Silver Mine and several veins nearby were trenched and assayed in 1989 and presented by Termuende (1993); a selection of that data is presented in table 3:     Showing Metal Tenor Mineralogy Vein Structure Host rock Ar40/Ar39 age B-Zone Au, Pb ± Zn Py, Apy ± Au NW-striking qtz veins offset by N-trending dextral faults DOWNEY: sericite schist, sericitic qtzite, minor shale  Hibernian Au, Ag, Pb, Zn Py, Gn, Sp, Ttr, Ank ± Apy Subvertical, striking ENE DOWNEY: sericite schist, mudstone 137.4 ± 1.6 Ma * Jewellery Shop Au, Ag, Pb  Py, Apy, Gn ± Ttr, Acan NW-striking qtz veins offset by N-trending dextral faults DOWNEY: graphitic schist, sericitic schist 141.0 ± 1.6 Ma * Penny Creek Au, Ag  cut by N-trending faults sericitic qtzite 135 - 142 Ma † Silver Mine (Portal Area) Ag Gn, Ttr, Mlc, Azr ± Sch, Acan, Bn subvertical, striking NNW HARDSCRABBLE: black shale, sericite schist 135 - 138 Ma † Silver Mine (5100 Pit) Ag, Cu, Pb, Zn Gn, Ttr, Mlc, Azr ± Sch, Acan, Bn subvertical, striking NNW HARDSCRABBLE: black shale, sericite schist 135 - 138 Ma † Varicose Vein Au, Ag   sericite schist, silicified sericite schist  * from Mortensen et al., 2011     † from Allan, M., pers. comm. 2017      Table 3. Summary of Ag-bearing veins in the Cunningham Creek area (After Termuende, 1993).    30   Figure 19. Regional map showing relative positions of BC vein and Silver Mine vein, plus other veins mentioned in this study.    Auriferous veins of the CGD are typically dominated by pyrite, with accessory cosalite (Pb2Bi2S5) as one of the most common accessory sulphides, whereas argentiferous veins in the Silver Mine area contain significant tetrahedrite ((Cu,Fe)12Sb4S13), galena (PbS), sphalerite (ZnS), and scheelite (CaWO4) (Fig. 20); some reports (e.g. Termuende, 1990) have also noted the presence of argentite/acanthite (Ag2S) in the Jewellery Shop and Silver Mine showings.  31   Figure 20. Photomicrographs demonstrating vein mineralogy at Penny Creek and Silver Mine. (I) RG16-CB16 (RL) Photomicrograph, 4x. Interstitial galena (Gn) and tetrahedrite (Ttr) are mutually intergrown. Subhedral pyrite (Py) is disseminated. (II) RG16-CB16 (RL) Photomicrograph, 50x. Anhedral, interstitial galena grows around euhedral pyrite. Covellite(?) is found on the interface between gangue minerals and galena. (III) RG16-CB15b (PPL) and (IV) RG16-CB15b (RL) Photomicrograph, 4x. Tetrahedrite fills fractures in sphalerite (Sp); interstitial galena grows against sphalerite and tetrahedrite; subhedral pyrite grains are found at the interfaces between phases. (V) RG16-CB23 (PPL + RL) Photomicrograph, 4x. Locally, sphalerite grows around scheelite (Sch); scheelite is cut by relatively undeformed carbonate veinlets; galena is interstitial and grows against sphalerite. Scheelite is distinguished from sphalerite by colour (sphalerite is brown-orange) and its varying interference colours, up to first-order yellow (sphalerite is isotropic); this can be seen in (VI).    32  5.2  Formation and Mineralization of Strike Veins   Strike veins (sometimes called ‘A’ veins) in the CGD are generally northwest- to north-northwest trending and continuous along strike for up to hundreds of meters. The BC vein is the best example of a strike vein in the CGD, though smaller strike veins (e.g. Black Bull and Canusa veins) are found nearby. Breccia fragments within the BC vein show rotated S2 fabrics, and relatively undeformed extensional veins locally connect with the vein, suggesting some D2 deformation occurred prior to vein formation. On vein surfaces, striations and rodding parallel to L2 indicate the vein has been subjected to some D2 deformation. The BC vein (and presumably other strike veins in the CGD) is interpreted to have formed during late D2 deformation, possibly during active displacement along the BC fault in which it is hosted (Rhys and Ross, 2001).   The BC vein is a fault filling vein located within the BC fault system, a steeply northeast-dipping fault with gouge fabrics recording both dextral and reverse components of motion during most recent displacement (Rhys and Ross, 2001). The BC vein, and other strike veins, are misoriented with respect to the inferred maximum stress (σ1) direction. In the CGD, strike faults and their associated veins preferentially form in less competent lithologies, suggesting there may be a rheologic control on the formation of these veins (Rhys and Ross, 2001). Planes of rheologic contrast (for example, between the highly deformable carbonaceous metapelites and the more competent psammites) could be the locus for the initiation of a lower-angle thrust fault shear zone, which is continually reactivated and steepened over time as wall rock accommodates some regional shortening (Sibson et al., 1988). Alternatively, normal faults formed during extension could be reactivated as reverse faults if the region is subsequently shortened. Supralithostatic fluid pressures and low confining pressure are required to reactivate severely misoriented reverse faults (Sibson, 1990); evidence for elevated fluid pressure is abundant in the CBD, in the form of extensional northeasterly-striking veins.  Zoning textures (e.g. within the Silver Mine vein) are indicative of episodic faulting and filling (± mineralizing), as in Sibson’s (1988) fault valve model: failure is triggered by crustal pore fluid pressure attaining some critical pressure; dilatancy along the rupture zone  33  causes fluid pressure to drop; hydrothermal minerals precipitate in response to dropping fluid pressure, and seal the fault; the process repeats once the fault is sealed and fluid pressure begins to accumulate once again.     5.3  Genetic Models for Argentiferous Veins   Silver Mine and surrounding argentiferous veins are classified by the British Columbia Geological Survey as polymetallic silver-lead-zinc (± gold) veins. There are three genetic models summarized by Beaudoin and Sangster (1996):  Magmatic differentiation model: Chalcophile elements (e.g. Pb, Zn, Ag) are concentrated in the fluid phase of a differentiating magma and are subsequently expelled to form polymetallic veins, dikes, and associated mafic and ultrapotassic intrusions.  Magmatic-hydrothermal model: Heat from syngenetic intrusions drives the hydrothermal system at moderate temperatures (250-300˚C). Carbonaceous host rocks may play a role in buffering hydrothermal fluids and may also provide a metal source.  Deep metamorphic fluid model: Hydrothermal fluids use deep crustal faults as passages to higher crustal levels, where mixing with upper-crustal fluids and first boiling drives mineral precipitation.  Lamprophyre dikes do cross-cut the main vein at Silver Mine, likely exploiting similar structural weaknesses (i.e. extensional cracks, faults) as veins in the CGD. These intrusions, however, are approximately 20 m.y. younger than the vein; it is very unlikely that they played a role in mineralization. The deep metamorphic fluid model is the only above-mentioned model that is permissive based on the large age difference between lamprophyres and veins. Results of a Pb-isotope study of gold-bearing deposits and occurrences in the CGD indicate that most of the lead in auriferous veins is derived from relatively local sources, either from immediate host rocks or from rock units immediately underlying them (Mortensen et al., 2011); it is possible that the metals in argentiferous veins are also locally     34  sourced. Polymetallic silver and tungsten veins appear to be confined within or nearby the Hardscrabble Mountain succession (Fig. 21), while more gold-rich veins appear to be located in the Downey succession (e.g. Blann, 1995) which also suggests host rock has a strong influence on metal tenor in veins.    6.0  CONCLUSION   6.1  Summary  Silver Mine, situated within the Hardscrabble Mountain succession of the Barkerville subterrane, is a north-northwest striking, steeply northeast-dipping dextral shear vein filling a fault between carbonaceous metapelites to the west and phyllitic psammites to the east. The vein is interpreted to be a strike vein, structurally and temporally similar to the BC vein further to the north, likely formed by reactivation of a pre-existing structure. Under conditions of continuous northeast-directed shortening, it is possible that the Silver Mine vein initiated as a thrust fault along a plane of rheological contrast, and was gradually rotated and continually reactivated as relatively ductile host rock accommodated some regional shortening. Ar40/Ar39 geochronology of hydrothermal muscovite in both Silver Mine and Penny Creek give ages of ~135-142 Ma, similar to nearby gold-bearing veins along Cunningham Creek.  The Silver Mine vein is mineralized with galena, sphalerite, tetrahedrite and scheelite with minor arsenopyrite. Trace malachite and azurite are present as weathering products of tetrahedrite. Texturally, the vein is zoned parallel to vein walls, indicating episodic fracturing and mineralizing events. Northeast-striking lamprophyre dikes cut the vein at Silver Mine, but they are approximately 20 m.y. younger than the vein and would not have played a role in mineralization.  35    Figure 21. Map showing trends of Ag-polymetallic veins and Ag-W bearing veins compared to all other minfile occurrences in the area. Note how both Ag-polymetallic and Ag-W veins are concentrated near the Hardscrabble Mtn succession.  36  Pressurizing metamorphic fluids, possibly scavenging metals from relatively local sources, likely triggered reactivation of the high-angle reverse fault in which the Silver Mine vein resides; dilation along the rupture plane allows hydrothermal minerals to precipitate due to a drop in fluid pressure.  The relatively more carbonaceous and deformable Hardscrabble Mountain succession of the Barkerville subterrane appears to have some influence on metal tenor in the veins it hosts (Fig. 21), also supporting locally sourced fluids.   6.2  Future Work   Argentiferous veins in the CGD warrant further study to determine the extent of mineralization and the origin of metals within them. In order to improve our spatial understanding of the veins, various geophysical methods could be employed. The carbonaceous metapelite that comprises the footwall of the fault would be a suitable target for an electromagnetic (EM) survey. The vein itself may be a suitable target for a resistivity survey. Quartz is resistive and sulfides are conductive, so it may even be possible to see which parts of the vein are mineralized and which parts are barren. Lamprophyre dikes are more magnetically susceptible than host rocks, so a high-resolution ground magnetic survey could help trace such features. It would be useful to investigate the provenance of lead in the argentiferous veins, to determine whether the metal budget of these veins also reflects high Pb-concentrations in the host rock. Pb-isotope signatures could be obtained for different reservoirs, including the Paleozoic Pb-Zn occurrences in the sedimentary sequences hosting the veins, and compared with Pb-isotopes from veins. Additionally, a fluid inclusion study could be performed to determine temperature and pressure of vein formation. Together, these studies would aid in constraining a genetic model for the Ag-rich polymetallic veins.    37  References   Allan, M. (2017): Structural Setting of Gold in the Cariboo; Presentation for EOSC422 at the University of British Columbia, February 6, 2017.  Beaudoin, G. and Sangster, D.F. (1996): Clastic Metasediment-Hosted Vein Silver-Lead-Zinc, in Geology of Canadian Mineral Deposit Types; (ed.) O.R. Eckstrand, W.D. Sinclair, and R.I. Thorpe; Geological Survey of Canada, Geology of Canada vol. 8, pp. 393-398.  Blann, D.E. (1995): Geological Report on the Cunningham Creek Prospect on behalf of Clansmen Resources Ltd.; B.C. Ministry of Energy, Mines and Petroleum Resources, Assessment Report 24 056, 12 p. plus appendices.  Dzick, W. (2015): Technical report on the Cow Mountain property for Barkerville Gold Mines Ltd; NI43-101, 237 p.  Ferri, F. and Schiarizza, P. (2006): Reinterpretation of the Snowshoe Group stratigraphy across a southwest-verging nappe structure and its implications for regional correlations within the Kootenay Terrane; in Paleozoic Evolution and Metallogeny of Pericratonic Terranes at the Ancient Pacific Margin of North America, M. Colpron and J.L. Nelson (ed.), Canadian and Alaskan Cordillera: Geological Association of Canada, Special Paper 45, p. 415–432.  Levson, V.M. and Giles, T.R. (1993): Geology of Tertiary and Quaternary gold-bearing placers in the Cariboo region, British Columbia (93A, B, G, H); BC Ministry of Energy, Mines and Petroleum Resources, Bulletin 89, 202 p.  Mortensen, J.K., Rhys, D.A. and Ross, K. (2011): Investigations of orogenic gold deposits in the Cariboo gold district, east-central British Columbia (parts of NTS 093A, H): final report; in Geoscience BC Summary of Activities 2010, Geoscience BC, Report 2011-1, p. 97–108.  Passchier, C. W., and Trouw, R. A. (1996): Microtectonics, Vol. 2: Springer.  Rhys, D.A., Mortensen, J.K. and Ross, K. (2009): Investigations of orogenic gold deposits in the Cariboo gold district, east-central British Columbia (parts of NTS 093A, H): progress report; in Geoscience BC Summary of Activities 2008, Geoscience BC, Report 2009-1, p. 49– 74.     38  Rhys, D.A. and Ross, K.V. (2001): Evaluation of the geology and exploration potential of the Bonanza Ledge zone, and adja- cent areas between Wells and Barkerville, east-central Brit- ish Columbia; internal company report prepared for International Wayside Gold Mines Ltd., 110 p.  Schiarizza, P. and Ferri, F. (2003): Barkerville Terrane, Cariboo Lake to Wells: a new look at stratigraphy, structure and regional correlations of the Snowshoe Group; in Geological Fieldwork 2002, BC Ministry of Energy, Mines and Petroleum Resources, Paper 2003-1, p. 79–96.  Sibson, R. H., Robert, F., and Poulsen, K. H. (1988): High-angle reverse faults, fluid-pressure cycling, and mesothermal gold-quartz deposits; Geology vol. 16, pp. 551-555.  Sibson, R. H. (1990): Rupture Nucleation on Unfavorably Oriented Faults; in Bulletin of the Seismological Society of America, vol. 80, no. 6, pp. 1580-1604.  Struik, L.C. (1988): Structural geology of the Cariboo Gold Mining District, east-central British Columbia; Geological Survey of Canada, Memoir 421, 100 p.  Termuende, T. (1990): Geological report on the Craze Creek (Cunningham) property for Loki Gold Corporation; BC Ministry of Energy, Mines and Petroleum Resources, Assessment Report 19 793, 21 p. plus maps.  Tipper, H.W. (1971): Glacial Geomorphology and Pleistocene History of Central British Columbia; Geological Survey of Canada, Bulletin 196, 89 p.      39  Appendix A: Sample Database   Sample_ID Source Sampler Time Area Zone RG16-CB01 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB02 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB03 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB04 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB05a BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB05b BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB06 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB07 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB08 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB09 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB10 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB11 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB12 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB13 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB14 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB15 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine    40  Appendix A: Sample Database   Loc_Desc Coord_Notes Sample_Type Unit Adit level; dike in contact with wall rock, west of adit Coordinates obtained from digitized points in ArcMap in situ Diorite Dike Adit level; dike, west of adit Coordinates obtained from digitized points in ArcMap in situ Diorite Dike Float on road between adit level and 5100 pit Coordinates obtained from digitized points in ArcMap float Lamprophyre Float on road between adit level and 5100 pit Coordinates obtained from digitized points in ArcMap float Lamprophyre 5100 pit Coordinates obtained from digitized points in ArcMap float/mine waste Vein 5100 pit Coordinates obtained from digitized points in ArcMap float/mine waste Vein Above 5100 pit Coordinates obtained from digitized points in ArcMap in situ Lamprophyre 5100 pit Coordinates obtained from digitized points in ArcMap in situ Phyllitic psammite Adit level; rough outcrop east of adit Coordinates obtained from digitized points in ArcMap float Phyllitic psammite Adit level; west side of adit near opening Coordinates obtained from digitized points in ArcMap  Phyllitic psammite Adit level; west side of adit near opening Coordinates obtained from digitized points in ArcMap  Carbonaceous metapelite  Coordinates obtained from digitized points in ArcMap a, b, c Carbonaceous metapelite Adit level; waste pile SE of adit Coordinates obtained from digitized points in ArcMap mine waste Vein Adit level; waste pile SE of adit Coordinates obtained from digitized points in ArcMap mine waste Vein Adit level; waste pile SE of adit Coordinates obtained from digitized points in ArcMap mine waste Vein Adit level; waste pile SE of adit Coordinates obtained from digitized points in ArcMap mine waste Vein    41  Appendix A: Sample Database   Sample_Description brown - rusty brown weathered, with some yellow brown (limonite?), cool grey fresh; massive; porphyritic with dark grey 1-2mm phenos and abundant very fine-grained pyrite brown - rusty orange-brown weathered, cool grey fresh; massive; abundant very fine-grained pyrite; thick ~1cm weathering rind; cut with thin (< 1mm) qtz veins rusty brown weathered (limonite?), cool grey fresh; massive; porphyritic with white phenos up to 3mm; contains xenoliths of qtz (vein qtz?) and wall rock rusty brown weathered (limonite?), cool grey fresh; massive; porphyritic with white phenos up to 3mm, larger of which have green in their centres; fewer and smaller phenos on one side (chilled margin) white, coarse-grained qtz containing massive tetrahedrite intergrown with arsenopyrite, disseminated galena white, coarse-grained qtz containing massive tetrahedrite, disseminated galena and small amounts of pyrite brown - rusty orange-brown weathered, cool grey fresh; massive; very fine-grained and mildly porphyritic; contains biotite, minor (secondary?) euhedral pyrite; cut with thin (< 1mm) qtz-py veins; pyrite concentrated around areas of silicification orange-brown - yellowish grey weathered, cool grey fresh; weakly foliated; very fine-grained with abundant fine- to very fine-grained euhedral pyrite; cut by chaotic qtz veins, most of which very roughly follow foliations; thicker (1 - 7mm), milky qtz veins contain trace amounts of tetrahedrite (poss. galena) while thin (< 1mm) more glassy veins contain small amounts of pyrite (uncertain about relative timing of veins). rusty orange-brown weathered, cool grey fresh; well foliated; flaggy cleavage; very fine-grained, with numerous foliform qtz veins up to ~3mm wide pale yellow-orange to orange-brown weathered, greeny grey fresh; very fine grained; fissile - flaggy cleavage; mica(?) defining irregular but mainly parallel foliations; foliation surfaces have soapy lustre while fractured surfaces are dull and earthy;  rusty brown weathered, dark grey fresh; very fine-grained; flaggy cleavage; graphite(?) defining undulating, irregular foliations; foliation surfaces have greasy lustre while other surfaces are dull and earthy; diagenetic qtz veins (parallel to foliations) up to 4mm but mainly < 1mm wide; cut by erratic qtz veinlets up to 7mm wide. rusty yellow - orange-brown weathered, dark grey fresh; very fine-grained; flaggy cleavage; graphite(?) defining foliations; foliation surfaces have greasy lustre while other surfaces are dull and earthy white, coarse-grained qtz containing bands of net-textured(?) - disseminated galena with trace tetrahedrite white, coarse-grained qtz containing bands of massive - dessiminated tetrahedrite white, coarse-grained qtz containing massive tetrahedrite (and associated azurite+malachite staining), disseminated galena white, coarse-grained qtz containing massive tetrahedrite, disseminated galena     42  Appendix A: Sample Database   Rock_Class Datum UTM_Zone UTM_Easting UTM_Northing Igneous NAD83 10N 612,188 5,863,310 Igneous NAD83 10N 612,188 5,863,310 Igneous NAD83 10N 612,175 5,863,330 Igneous NAD83 10N 612,189 5,863,340 Hydrothermal NAD83 10N 612,197 5,863,340 Hydrothermal NAD83 10N 612,197 5,863,340 Igneous NAD83 10N 612,195 5,863,340 Metasedimentary NAD83 10N 612,198 5,863,340 Metasedimentary NAD83 10N 612,226 5,863,300 Metasedimentary NAD83 10N 612,209 5,863,300 Metasedimentary NAD83 10N 612,208 5,863,300 Metasedimentary NAD83 10N 612,187 5,863,320 Hydrothermal NAD83 10N 612,227 5,863,290 Hydrothermal NAD83 10N 612,227 5,863,290 Hydrothermal NAD83 10N 612,227 5,863,290 Hydrothermal NAD83 10N 612,227 5,863,290     43  Appendix A: Sample Database   RG16-CB16 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB17 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB18 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sat Aug 20 Cariboo Silver Mine RG16-CB19 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo  RG16-CB20 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo  RG16-CB21 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo  RG16-CB22 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo  RG16-CB23 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo  RG16-CB24 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo  RG16-CB25 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo  RG16-CB26 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo Silver Mine RG16-CB27 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo Silver Mine RG16-CB28 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo Silver Mine RG16-CB29 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo Silver Mine RG16-CB30 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo Silver Mine RG16-CB31 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo Silver Mine RG16-CB32 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo Silver Mine RG16-CB33 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Sun Aug 21 Cariboo Silver Mine RG16-CB34 no sample     RG16-CB35 BC Orogoenic Gold Project 2016 - Geoscience BC R. Gavin Mon Aug 22 Cariboo Penny Creek     44  Appendix A: Sample Database   Adit level; waste pile SE of adit Coordinates obtained from digitized points in ArcMap mine waste Vein Adit level; waste pile SE of adit Coordinates obtained from digitized points in ArcMap mine waste Vein Adit level; waste pile SE of adit Coordinates obtained from digitized points in ArcMap mine waste Vein Subcrop in stream near Silver Mine Coordinates of general outcrop area float Vein Subcrop in stream near Silver Mine Coordinates obtained from digitized points in ArcMap float Vein Subcrop in stream near Silver Mine Coordinates obtained from digitized points in ArcMap float Vein Subcrop in stream near Silver Mine Coordinates obtained from digitized points in ArcMap float Vein Subcrop in stream near Silver Mine Coordinates obtained from digitized points in ArcMap float Vein Subcrop in stream near Silver Mine Coordinates obtained from digitized points in ArcMap float Vein Subcrop in stream near Silver Mine Coordinates obtained from digitized points in ArcMap float Vein Adit level; above opening to the NE Coordinates obtained from digitized points in ArcMap in situ Phyllitic psammite Adit level; float collected on W side of adit Coordinates obtained from digitized points in ArcMap float Carbonaceous metapelite Adit level; float collected on W side of adit Coordinates obtained from digitized points in ArcMap float Carbonaceous metapelite Adit level; float collected on W side of adit Coordinates obtained from digitized points in ArcMap float Carbonaceous metapelite Adit level; float collected on W side of adit Coordinates obtained from digitized points in ArcMap float Carbonaceous metapelite Adit level; float collected on W side of adit Coordinates obtained from digitized points in ArcMap float Carbonaceous metapelite Adit level; float collected on W side of adit Coordinates obtained from digitized points in ArcMap float Carbonaceous metapelite Adit level; float collected on W side of adit Coordinates obtained from digitized points in ArcMap float Carbonaceous metapelite      Coordinates obtained from digitized points in ArcMap float/mine waste Vein    45  Appendix A: Sample Database   white, coarse-grained qtz containing bands of massive - dessiminated tetrahedrite white, coarse-grained qtz containing intergrown tetrahedrite and net-textured(?) galena white, coarse-grained qtz containing py in bands white, coarse-grained qtz with bands of galena(?) and scheelite white, coarse-grained qtz containing disseminated tetrahedrite and sphalerite, with malachite and azurite staining white, coarse-grained, vuggy qtz with galena and scheelite white, coarse-grained qtz with tetrahedrite(?) and scheelite, with kaolinite white, coarse-grained qtz with galena and scheelite, minor sphalerite white, coarse-grained, vuggy qtz with galena and scheelite  orange- to rusty-brown weathered, greenish-silver fresh; foliated with flaggy cleavage and weak secondary cleavage at ~60 deg. To foliations; micaceous (muscovite) brown weathered, dark grey fresh; dull to earthy lustre (less greasy than some other carb. semipelite samples) fissile to flaggy cleavage, well foliated with kink fold; ~1mm or less py grains with qtz strain shadows brown weathered, dark grey fresh; dull to greasy lustre; fissile to flaggy cleavage, well foliated; ~1mm or less py grains with qtz strain shadows brown weathered, dark grey fresh; dull to earthy lustre (less greasy than some other carb. semipelite samples) fissile to flaggy cleavage, well foliated; ~1mm or less py grains with qtz strain shadows brown weathered, dark grey fresh; dull to earthy lustre (less greasy than some other carb. semipelite samples) fissile to flaggy cleavage, well foliated; ~1mm or less py grains with qtz strain shadows brown weathered, dark grey fresh; dull to earthy lustre (less greasy than some other carb. semipelite samples) fissile to flaggy cleavage, well foliated brown weathered, dark grey fresh; dull to greasy lustre; fissile to flaggy cleavage, well foliated brown weathered, dark grey fresh; dull to greasy lustre; fissile to flaggy cleavage, well foliated; cut with one blobby qtz vein ranging in width from 3mm - 1.5cm  white, coarse grained qtz vein with coarse grained py blebs. Vein chunk is approx. 10cm thick with wall rock on both sides     46  Appendix A: Sample Database   Hydrothermal NAD83 10N 612,227 5,863,290 Hydrothermal NAD83 10N 612,227 5,863,290 Hydrothermal NAD83 10N 612,227 5,863,290 Hydrothermal NAD83 10N 612,294 5,863,055 Hydrothermal NAD83 10N 612,309 5,863,070 Hydrothermal NAD83 10N 612,310 5,863,080 Hydrothermal NAD83 10N 612,309 5,863,070 Hydrothermal NAD83 10N 612,309 5,863,070 Hydrothermal NAD83 10N 612,305 5,863,080 Hydrothermal NAD83 10N 612,304 5,863,070 Metasedimentary NAD83 10N 612,212 5,863,310 Metasedimentary NAD83 10N 612,177 5,863,310 Metasedimentary NAD83 10N 612,182 5,863,310 Metasedimentary NAD83 10N 612,196 5,863,300 Metasedimentary NAD83 10N 612,188 5,863,300 Metasedimentary NAD83 10N 612,180 5,863,310 Metasedimentary NAD83 10N 612,173 5,863,310 Metasedimentary NAD83 10N 612,175 5,863,310      Hydrothermal NAD83 10N 611,495 5,863,040     47  Appendix B: Ar-Ar data   Sample no Mineral  J ± (1s)     RG16-CB06a biotite  1.873E-03 1.474E-06                     Relative Isotopic abundances (fAmps)* Power Ar40 ± Ar39 ± Ar38 ± Ar37 ± (%)  (1s)  (1s)  (1s)  (1s)                   GRAIN 1                  0.50 0.9290 0.0657 0.0962 0.0647 -0.0144 0.0319 -0.0256 0.0244 2.00 286.2063 0.0966 8.9389 0.0600 0.1659 0.0302 0.0673 0.0285 4.00 829.2939 0.1328 27.3711 0.0659 0.3588 0.0308 -0.0472 0.0282 5.00 1133.9860 0.1335 33.2143 0.0711 0.3097 0.0298 0.0126 0.0242          GRAIN 2                  0.50 0.0362 0.0592 -0.1952 0.0670 0.0585 0.0309 -0.0363 0.0267 2.00 15.5323 0.0687 0.6516 0.0611 0.0226 0.0295 0.0195 0.0278 4.00 467.2814 0.1028 14.5612 0.0604 0.1416 0.0325 -0.0389 0.0292 5.00 176.6974 0.0920 4.9596 0.0640 -0.0140 0.0306 -0.0125 0.0261          GRAIN 4                  0.50 6.1172 0.0633 0.2068 0.0706 0.0013 0.0296 0.0316 0.0265 2.00 233.9247 0.0778 6.4750 0.0646 0.0625 0.0299 0.1414 0.0256 4.00 185.6448 0.0791 5.3014 0.0581 0.0646 0.0273 0.2008 0.0265 5.00 7.7635 0.0599 0.1983 0.0612 0.0039 0.0270 0.0317 0.0287          * Corrected for blank, mass discrimination, and radioactive decay    Sensitivity 6.312E-17 ± 1.047E-18 (mol/fAmp)                    48  Appendix B: Ar-Ar data                                               40Ar*/39Ar (K)     Ar36 ± Ca/K ± Cl/K ± ± 40Ar* Age ±  (1s)  (1s)  (1s)  (1s) (%) (Ma) (1s)                                             0.0018 0.0007 -2.860 3.397 -0.479 1.033 3.979 3.505 41.27 13.4 11.8 0.1226 0.0019 0.081 0.035 0.011 0.010 27.951 0.214 87.35 92.1 0.7 0.1216 0.0017 -0.019 0.011 0.000 0.003 28.966 0.090 95.66 95.3 0.3 0.0616 0.0015 0.004 0.008 -0.009 0.003 33.571 0.093 98.39 110.0 0.3                                  -0.0006 0.0007 2.008 1.652 -0.906 0.567 -1.006 1.170 540.47 -3.4 4.0 -0.0019 0.0010 0.323 0.467 0.067 0.134 24.710 2.430 103.72 81.6 7.8 0.0345 0.0012 -0.029 0.022 -0.008 0.007 31.369 0.146 97.81 103.0 0.5 0.0075 0.0008 -0.029 0.060 -0.044 0.018 35.154 0.473 98.73 115.1 1.5                                  0.0080 0.0008 1.660 1.520 -0.039 0.423 18.203 6.522 61.55 60.5 21.3 0.0338 0.0012 0.237 0.043 -0.010 0.014 34.576 0.365 95.76 113.2 1.2 0.0200 0.0011 0.411 0.055 -0.002 0.015 33.901 0.392 96.86 111.1 1.2 -0.0002 0.0007 1.798 1.739 0.022 0.402 39.463 12.570 100.82 128.7 39.6                    49  Appendix B: Ar-Ar data   Sample no Mineral  J ± (1s)      RG16-CB03 biotite  1.896E-03 2.210E-06                         Relative Isotopic abundances (fAmps)* Power Ar40 ± Ar39 ± Ar38 ± Ar37 ± Ar36 (%)  (1s)  (1s)  (1s)  (1s)                      GRAIN 1                    0.50 7.6423 0.0638 0.1868 0.0624 0.0517 0.0294 -0.0206 0.0259 0.0177 1.00 120.8270 0.0770 2.0679 0.0643 0.0185 0.0275 0.0441 0.0281 0.1966 2.00 313.1214 0.0988 8.3080 0.0646 0.1241 0.0319 0.0696 0.0286 0.0922 4.00 345.6150 0.1211 9.8728 0.0626 0.0899 0.0318 0.0828 0.0252 0.0147           GRAIN 2                    0.50 6.5280 0.0691 0.1942 0.0624 0.0619 0.0307 0.0790 0.0267 0.0143 1.00 8.6537 0.0673 0.2365 0.0629 -0.0376 0.0298 0.0053 0.0265 0.0004 2.00 116.4061 0.0767 3.2330 0.0591 0.0703 0.0300 0.0378 0.0258 0.0118 4.00 145.6646 0.0761 4.2184 0.0566 -0.0013 0.0319 -0.0107 0.0279 0.0022           GRAIN 3                    0.50 8.3481 0.0626 0.1608 0.0622 0.0559 0.0298 0.0539 0.0269 0.0229 1.00 30.6838 0.0656 0.8036 0.0641 0.0887 0.0334 0.3755 0.0289 0.0255 2.00 148.3816 0.0716 4.2480 0.0555 0.0847 0.0301 0.1230 0.0256 0.0111 4.00 140.2751 0.0776 4.0719 0.0639 0.0112 0.0325 0.2493 0.0265 0.0071           * Corrected for blank, mass discrimination, and radioactive decay     Sensitivity 6.312E-17 ± 1.047E-18 (mol/fAmp)          50  Appendix B: Ar-Ar data                                            40Ar*/39Ar (K)     ± Ca/K ± Cl/K ± ± 40Ar* Age ± (1s)  (1s)  (1s)  (1s) (%) (Ma) (1s)                                         0.0012 -1.080 1.421 0.714 0.528 12.841 4.833 31.41 43.4 16.1 0.0023 0.208 0.135 -0.061 0.039 30.323 1.031 51.92 100.8 3.3 0.0018 0.082 0.034 0.002 0.011 34.394 0.286 91.31 114.0 0.9 0.0011 0.082 0.025 -0.010 0.010 34.549 0.230 98.75 114.5 0.7                               0.0010 3.993 1.901 0.850 0.547 12.047 4.297 35.81 40.7 14.4 0.0011 0.218 1.112 -0.497 0.397 36.024 9.993 98.50 119.2 32.0 0.0011 0.114 0.079 0.026 0.027 34.916 0.667 97.03 115.6 2.1 0.0008 -0.025 0.066 -0.037 0.022 34.353 0.480 99.55 113.8 1.5                               0.0010 3.298 2.126 0.897 0.656 10.007 4.447 19.27 33.9 14.9 0.0011 4.607 0.522 0.268 0.125 29.033 2.433 75.96 96.7 7.9 0.0009 0.285 0.060 0.021 0.021 34.155 0.466 97.83 113.2 1.5 0.0010 0.604 0.066 -0.028 0.024 33.947 0.556 98.58 112.5 1.8               51  Appendix B: Ar-Ar data   Sample no Mineral  J ± (1s)     MA16-CB21 sericite  0.00187 2.89E-06             Aliquot 1     Relative Isotopic abundances (fAmps)* Power Ar40 ± Ar39 ± Ar38 ± Ar37 ± (%)  (1s)  (1s)  (1s)  (1s)                   0.60 1019.7060 0.1331 28.6609 0.0628 0.2890 0.0279 0.0175 0.0272 0.80 1344.0960 0.1325 36.4138 0.0695 0.4536 0.0307 0.0621 0.0266 1.00 1949.5300 0.1923 50.7843 0.0658 0.5775 0.0323 0.0279 0.0246 1.20 2620.5610 0.2150 66.5312 0.0704 0.7363 0.0292 0.0150 0.0284 1.40 2810.1640 0.2051 69.2039 0.0648 0.8197 0.0316 -0.0078 0.0278 1.60 2640.7630 0.1964 63.4495 0.0763 0.7763 0.0296 0.0426 0.0268 1.80 3026.9280 0.2451 72.2413 0.0664 0.8894 0.0298 0.0338 0.0293 2.00 4493.3170 0.2664 105.8490 0.0751 1.2867 0.0312 0.0273 0.0273 2.50 6468.9710 0.3256 149.7316 0.0804 1.7336 0.0279 0.1259 0.0267 3.00 3936.3470 0.2875 90.3751 0.0740 1.1426 0.0317 -0.0799 0.0271 4.00 686.4806 0.1239 15.6509 0.0663 0.1875 0.0302 -0.0026 0.0301          * Corrected for blank, mass discrimination, and radioactive decay   Sensitivity 6.312E-17 ± 1.047E-18 (mol/fAmp)        52  Appendix B: Ar-Ar data                                               40Ar*/39Ar (K)     Ar36 ± Ca/K ± Cl/K ± ± 40Ar* Age ±  (1s)  (1s)  (1s)  (1s) (%) (Ma) (1s)                       0.0380 0.0011 0.005 0.008 -0.007 0.003 35.168 0.095 98.90 114.9 0.3 0.0151 0.0009 0.014 0.006 0.000 0.002 36.770 0.089 99.67 119.9 0.3 0.0136 0.0009 0.004 0.004 -0.003 0.002 38.289 0.073 99.79 124.7 0.2 0.0110 0.0010 0.001 0.004 -0.003 0.001 39.319 0.069 99.88 128.0 0.2 0.0113 0.0011 -0.001 0.003 -0.001 0.001 40.537 0.068 99.88 131.8 0.2 0.0116 0.0011 0.005 0.004 0.000 0.001 41.544 0.077 99.87 134.9 0.2 0.0114 0.0011 0.003 0.003 0.000 0.001 41.832 0.070 99.89 135.8 0.2 0.0142 0.0011 0.002 0.002 0.000 0.001 42.388 0.066 99.91 137.6 0.2 0.0208 0.0014 0.006 0.001 -0.002 0.001 43.140 0.063 99.91 139.9 0.2 0.0108 0.0009 -0.008 0.003 0.001 0.001 43.497 0.070 99.92 141.0 0.2 0.0034 0.0009 -0.002 0.016 -0.001 0.006 43.774 0.201 99.85 141.9 0.6                        53  Appendix B: Ar-Ar data   Sample no Mineral  J ± (1s)     MA16-CB15 sericite  0.0018682 2.81E-06              Aliquot 1     Relative Isotopic abundances (fAmps)*   Power Ar40 ± Ar39 ± Ar38 ± Ar37 ± (%)  (1s)  (1s)  (1s)  (1s)                   0.60 624.0143 0.1216 16.4920 0.0635 0.1870 0.0307 -0.0432 0.0273 0.80 1127.2590 0.1275 28.7491 0.0671 0.3200 0.0303 -0.0018 0.0270 1.00 1815.7030 0.1764 45.1025 0.0692 0.5957 0.0301 -0.0009 0.0269 1.20 2920.2570 0.2122 70.8310 0.0713 0.7707 0.0285 -0.0572 0.0274 1.40 4259.7120 0.2808 102.0787 0.0742 1.1738 0.0268 0.0214 0.0292 1.60 6017.5080 0.3489 141.5419 0.0754 1.6710 0.0306 -0.0599 0.0263 1.80 5725.4420 0.3630 133.2887 0.0760 1.5540 0.0294 -0.0058 0.0263 2.00 820.2759 0.1468 18.4292 0.0654 0.2972 0.0299 0.0306 0.0291 2.50 565.6137 0.1069 12.2355 0.0611 0.1722 0.0305 -0.0155 0.0277 3.00 211.1870 0.0780 4.0185 0.0601 0.1116 0.0322 -0.0390 0.0243 4.00 135.3280 0.0706 2.9874 0.0671 0.0444 0.0285 0.0168 0.0287          Aliquot 2                  0.60 692.6884 0.1284 17.2228 0.0645 0.2598 0.0302 -0.0020 0.0292 0.80 944.2154 0.1423 23.6368 0.0660 0.2990 0.0309 0.0304 0.0259 1.00 1529.7860 0.1614 37.4688 0.0670 0.4290 0.0311 -0.0065 0.0269 1.20 2756.9490 0.2345 64.9937 0.0671 0.7693 0.0310 0.0334 0.0282 1.30 2917.8760 0.2072 68.9578 0.0731 0.8245 0.0324 0.0039 0.0278 1.40 4095.8700 0.2738 96.9031 0.0712 1.1110 0.0306 -0.0016 0.0276 1.50 7516.9280 0.3460 177.7849 0.0817 2.1628 0.0307 0.0273 0.0291 1.60 5600.9820 0.3044 130.8172 0.0779 1.5279 0.0300 0.0099 0.0269 1.70 1103.4610 0.1359 25.8767 0.0653 0.2491 0.0294 0.0060 0.0296 1.80 600.0206 0.1190 14.1093 0.0638 0.1384 0.0331 0.0214 0.0270 2.00 395.0962 0.0930 9.2407 0.0640 -0.0057 0.0316 0.0175 0.0264 3.00 641.2839 0.1167 14.8298 0.0642 0.2051 0.0309 0.0508 0.0267          * Corrected for blank, mass discrimination, and radioactive decay     Sensitivity 6.312E-17 ± 1.047E-18 (mol/fAmp)      54  Appendix B: Ar-Ar data                                               40Ar*/39Ar (K)     Ar36 ± Ca/K ± Cl/K ± ± 40Ar* Age ±  (1s)  (1s)  (1s)  (1s) (%) (Ma) (1s)                       0.0300 0.0011 -0.022 0.014 -0.004 0.006 37.278 0.151 98.58 121.5 0.5 0.0207 0.0009 -0.001 0.008 -0.004 0.003 38.976 0.098 99.46 126.8 0.3 0.0357 0.0012 -0.001 0.005 0.002 0.002 40.002 0.069 99.42 130.0 0.2 0.0352 0.0013 -0.007 0.003 -0.004 0.001 41.059 0.051 99.64 133.3 0.2 0.0367 0.0014 0.001 0.002 -0.002 0.001 41.601 0.042 99.75 135.0 0.1 0.0583 0.0015 -0.004 0.002 -0.001 0.001 42.369 0.037 99.71 137.4 0.1 0.0356 0.0011 -0.001 0.002 -0.002 0.001 42.853 0.038 99.82 138.9 0.1 0.0038 0.0008 0.013 0.013 0.011 0.005 44.427 0.166 99.87 143.8 0.5 0.0056 0.0008 -0.011 0.019 0.005 0.007 46.068 0.240 99.71 148.9 0.7 0.0043 0.0007 -0.082 0.051 0.045 0.024 52.206 0.806 99.39 167.9 2.5 0.0021 0.0007 0.047 0.082 0.007 0.028 45.075 1.045 99.55 145.9 3.2                                  0.2348 0.0024 -0.001 0.014 0.001 0.005 36.171 0.147 89.98 118.0 0.5 0.0633 0.0014 0.010 0.009 0.000 0.004 39.136 0.115 98.02 127.3 0.4 0.0694 0.0015 -0.002 0.006 -0.003 0.002 40.259 0.078 98.66 130.8 0.2 0.0724 0.0016 0.004 0.004 -0.002 0.001 42.067 0.050 99.22 136.5 0.2 0.0416 0.0013 0.000 0.003 -0.001 0.001 42.113 0.050 99.58 136.6 0.2 0.0409 0.0014 -0.001 0.002 -0.002 0.001 42.120 0.037 99.70 136.7 0.1 0.0462 0.0018 0.001 0.001 0.000 0.001 42.181 0.027 99.82 136.8 0.1 0.0326 0.0014 0.000 0.002 -0.002 0.001 42.718 0.032 99.83 138.5 0.1 -0.0066 0.0011 0.002 0.010 -0.007 0.003 42.695 0.113 100.18 138.5 0.4 -0.0201 0.0012 0.013 0.017 -0.006 0.007 42.925 0.202 100.99 139.2 0.6 -0.0078 0.0010 0.016 0.025 -0.037 0.010 42.982 0.309 100.58 139.3 1.0 0.0018 0.0011 0.029 0.016 0.005 0.006 43.185 0.195 99.92 140.0 0.6               55  Appendix C: Short-Wave Infrared Spectrometry Data        00.020.040.060.080.10.120.140.16350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB01 (a)00.020.040.060.080.10.120.140.16350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB01 (b) 56  Appendix C: Short-Wave Infrared Spectrometry Data        00.050.10.150.20.250.3350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB0700.050.10.150.20.250.30.35350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB08 (a) 57  Appendix C: Short-Wave Infrared Spectrometry Data       00.050.10.150.20.250.30.35350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB08 (b)00.050.10.150.20.250.30.35350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB08 (c) 58  Appendix C: Short-Wave Infrared Spectrometry Data       00.050.10.150.20.250.30.35350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB0900.010.020.030.040.050.060.070.080.090.1350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB10 59  Appendix C: Short-Wave Infrared Spectrometry Data        00.050.10.150.20.250.30.35350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB1900.10.20.30.40.50.60.7350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB20 60  Appendix C: Short-Wave Infrared Spectrometry Data       00.10.20.30.40.50.6350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB21 (a)00.10.20.30.40.50.6350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB21 (b) 61  Appendix C: Short-Wave Infrared Spectrometry Data        00.050.10.150.20.25350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB26 (a)00.050.10.150.20.250.3350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB26 (b) 62  Appendix C: Short-Wave Infrared Spectrometry Data       00.050.10.150.20.250.30.35350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB26 (c)00.010.020.030.040.050.060.070.080.090.1350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB27 63  Appendix C: Short-Wave Infrared Spectrometry Data      00.020.040.060.080.10.120.14350 850 1350 1850 2350ReflectanceWavelength (nm)RG16-CB29 64  Appendix C: Short-Wave Infrared Spectrometry Data   Sample Scan Index Rock_type RG16-CB21 170220_00001.asd.sco FSFR.2106 Int=10.0 sec vein RG16-CB21 170220_00002.asd.sco FSFR.2106 Int=10.0 sec vein RG16-CB07 170220_00003.asd.sco FSFR.2106 Int=10.0 sec phyllitic psammite RG16-CB09 170220_00004.asd.sco FSFR.2106 Int=10.0 sec phyllitic psammite RG16-CB26 170220_00005.asd.sco FSFR.2106 Int=10.0 sec phyllitic psammite RG16-CB26 170220_00006.asd.sco FSFR.2106 Int=10.0 sec phyllitic psammite RG16-CB26 170220_00007.asd.sco FSFR.2106 Int=10.0 sec phyllitic psammite RG16-CB10 170220_00008.asd.sco FSFR.2106 Int=10.0 sec carbonaceous metapelite RG16-CB01 170220_00009.asd.sco FSFR.2106 Int=10.0 sec diorite dike RG16-CB01 170220_00010.asd.sco FSFR.2106 Int=10.0 sec diorite dike RG16-CB08 170220_00011.asd.sco FSFR.2106 Int=10.0 sec phyllitic psammite RG16-CB08 170220_00012.asd.sco FSFR.2106 Int=10.0 sec phyllitic psammite RG16-CB08 170220_00013.asd.sco FSFR.2106 Int=10.0 sec phyllitic psammite RG16-CB20 170220_00014.asd.sco FSFR.2106 Int=10.0 sec vein RG16-CB19 170220_00015.asd.sco FSFR.2106 Int=10.0 sec vein RG16-CB27 170220_00016.asd.sco FSFR.2106 Int=10.0 sec carbonaceous metapelite RG16-CB29 170220_00017.asd.sco FSFR.2106 Int=10.0 sec carbonaceous metapelite     65  Appendix C: Short-Wave Infrared Spectrometry Data   Rock_comments vuggy qtz w/ scheelite? float from subcrop in Penny Ck. SE of Silver Mine vuggy qtz w/ scheelite? float from subcrop in Penny Ck. SE of Silver Mine cut by extensional qtz-carb veinlets; 5100 pit just east of vein very weathered; Silver Mine adit level proximal to vein Silver Mine adit level, just above adit Silver Mine adit level, just above adit Silver Mine adit level, just above adit Silver Mine adit level, just west of vein fresher; Silver Mine adit level west of vein weathered; Silver Mine adit level west of vein fresher; Silver Mine adit level; float from scruffy outcrop east of vein weathered; Silver Mine adit level; float from scruffy outcrop east of vein fresher; Silver Mine adit level; float from scruffy outcrop east of vein float from subcrop in Penny Ck. SE of Silver Mine w/ scheelite? float from subcrop in Penny Ck. SE of Silver Mine Silver Mine adit level; float collected west of vein Silver Mine adit level; float collected west of vein     66  Appendix C: Short-Wave Infrared Spectrometry Data   TSA_S Mineral1 TSA_S Weight1 TSA_S Mineral2 TSA_S Weight2 TSA_S Error Dolomite 1 NULL NULL 232.19 Calcite 1 NULL NULL 236.01 Muscovite 0.762 Ankerite 0.238 126.67 Muscovite 1 NULL NULL 58.553 Muscovite 1 NULL NULL 125.54 Muscovite 0.751 Ankerite 0.249 96.121 Muscovite 1 NULL NULL 141.42 Dark NULL NULL NULL 10000 Aspectral NULL NULL NULL 10000 Aspectral NULL NULL NULL 10000 IntChlorite 0.582 Muscovite 0.418 37.709 IntChlorite 0.56 Muscovite 0.44 36.01 Muscovite 0.51 IntChlorite 0.49 53.005 Illite 1 NULL NULL 492.69 Dolomite 1 NULL NULL 225.31 Aspectral NULL NULL NULL 10000 Aspectral NULL NULL NULL 10000  

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
https://iiif.library.ubc.ca/presentation/dsp.52966.1-0347675/manifest

Comment

Related Items