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Geological setting of the Hedley gold skarn camp with specific reference to the French mine, south-central… Dawson, Garnet Linn 1994

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GEOLOGICAL SE flING OF TIlE HEDLEY GOLD SKARN CAMPWITH SPECIFIC REFERENCE TO THE FRENCH MINE, SOUTH-CENTRAL BRITISH COLUMBIAbyGARNET LINN DAWSONB.Sc., The University ofManitoba, 1981A THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFMASTER OF SCIENCEinTHE FACULTY OF GRADUATE STUDIES(Department of Geological Sciences)We accept this thesis as conformingto the required standard:THE UNIVERSITY OF BRITISH COLUMBIAJuly 1994©Garnet Linn DawsonIn presenting this thesis in partial fulfillment of therequirements for an advanced degree at the University of BritishColumbia, I agree that the Library shall make it freely availablefor reference and study. I further agree that permission forextensive copying of this thesis for scholarly purposes may begranted by the head of my department or by his or herrepresentatives. It is understood that copying or publication ofthis thesis for financial gain shall not be allowed without mywritten permission.(Signature)Department of____________________pThe University of British ColumbiaVancouver, CanadaDate 5LHABSTRACTThe Hedley gold skarn camp in south-central British Columbia is the second largest goldproducer in the province. From the period 1902 to 1955 about 51 million grams (1.6 million ounces) ofgold were produced from four gold bearing skarn deposits; over 95% of this came from the Nickel Plateand Mascot mines that mined underground a large skarn deposit centered on Nickel Plate Mountain. TheNickel Plate deposit was reopened in 1987 as a large tonnage, low grade open pit deposit; from 1987 tothe end of 1993, 18.6 million grams (0.54 million ounces) of gold were recovered from 7 236 430 tonnesmilled. The French mine produced 1.36 million grams of gold from 69 508 tonnes of ore during theperiods 1950 to 1955, 1957 to 1961, and in 1983.The camp is underlain predominantly by the sedimentary facies of the Late Triassic Nicola Groupthat unconformably overlies more deformed oceanic rocks of the middle to late Paleozoic Apex Mountaincomplex. The sedimentary facies of the Nicola Group is subdivided into four sedimentary and onevolcaniclastic formation that were deposited in a north trending, westward deepening, fault controlledbasin along the eastern margin of the main Nicola arc in Quesnellia. They are represented by: (i)siltstones and thick limestones as the shallow water Hedley formation, (ii) siltstones and thin limestonesas the intermediate depth Chuchuwayha formation, and (iii) argillite and rare limestone as the deeperwater Stemwinder formation. Collapse of this basin is marked by deposition of the Copperfield breccia,which separates the Hedley, Chuchuwayha and Stemwinder formations from the overlying volcaniclasticsof the Whistle formation. The Copperfield breccia is a limestone breccia that represents a catastrophicmassive gravity slide deposit derived from uplifted and faulted reef material with a provenance to the east.The overlying Whistle formation forms an extensive unit that grades from thinly laminated tuffaceoussiltstones at its base to massive alkalic and subalkalic intermediate to mafic ash. Three periods ofcalcalkaline intrusive activity and associated mineralization recognized are: (i) Late Triassic Hedleyintrusions (gold skarn), (ii) Early Jurassic Bromley batholith - Mount Riordan stock (minor W-Cu andindustrial garnet skarns), and (iii) Middle Jurassic Cahill Creek pluton (minor W-Mo porphyry andskarn), Lookout Ridge pluton and rhyolite porphyry dykes.111Hedley intrusions form a texturally diverse suite of intermediate to mafic calcalkaline dykes, sillsand stocks that are spatially and temporally associated with gold skarn mineralization. Features such aswavy sill contacts, destruction of sedimentary structures, peperite, quench textures, sedimentary dykes,and preliminary U-Pb zircon dates suggest that they preferentially intruded unconsolidated to poorlyconsolidated siltstone between beds of lithilled limestone in the Hedley formation. Implications of thissynsedimentaiy sill interpretation are: (i) contemporaneous sedimentation and intrusive volcanism, (ii) anextensional setting, and (iii) a shallow depth of intrusion and associated skarn formation. In addition, thisinterpretation helps to explain and integrate the lithologic, stratigraphic and structural controls to goldskarn mineralization in the camp.At the French mine gold-arsenopyrite-telluride mineralization is associated with skarn zones onboth sides of limestone - biotitic aphyric intrusion contacts. The skarn displays consistent mineralogicalzoning from (i) biotitic aphyric intrusion, (ii) orthoclase (endoskarn), (iii) Mg-rich clinopyroxene(endoskarn), (iv) Fe-rich clinopyroxene (endoskarn and exoskarn spanning the aphyric - limestonecontact) and (vi) Fe-rich garnet (exoskarn). Quartz, calcite, vesuvianite, scapolite, arsenopyrite, Cu and Fesuiphides, tellurides and associated gold occur in microfractures and vugs between the iron-rich garnet ±pyroxene skarn. This mineralogical zoning is complicated locally by crosscutting hydrothermaloverprinting. Late stage, retrograde alteration is limited, and is represented by minor replacement ofgarnet and clinopyroxene by chlorite ± actinolite ± titanite ± epidote.ivTABLE OF CONTENTSPageTITLE PAGE i.ABSTRACT U.TABLE OF CONTENTS iv.LIST OF TABLES vi.LIST OF FIGURES viii.LIST OF PLATES xi.ACKNOWLEDGMENTS XV.CHAPTER 1.0 INTRODUCTION ICHAPTER 2.0 REGIONAL GEOLOGY 5CHAPTER 3.0 GEOLOGY OF THE HEDLEY GOLD SKARN CAMP 63.1 Introduction 63.2 Apex Mountain Complex (unit 1) 93.3 Nicola Group 10Hedley formation (unit 2) 11Chuchuwayha formation (unit 3) 12Stemwinder formation (unit 4) 12Copperfield breccia (unit 5) 12Whistle formation (unit 6) 133.4 Hedley intrusions (unit 7) 17Stemwinder stock 21Toronto stock 21Nickel Plate sill complex 233.5 Bromley batholith (unit 8) 293.6 Mount Riordan stock (unit 9) 293.7 Cahill Creek pluton (unit 10) 303.8 Lookout Ridge pluton (unit 11) 313.9 Rhyolite porphyry (unit 12) 313.10 Skwel Peken formation (unit 13) 333.11 Minor intrusions 353.12 Structure 373.13 Galena lead isotopes 423.14 Discussion 45CHAPTER 4.0 GEOLOGY OF THE FRENCH MINE GOLD SKARN 544.1 Introduction 544.2 Geology of the French - Good Hope mine area 554.2.1 Apex Mountain complex (unit 1) 584.2.2 Nicola Group (units 2-6) 644.2.3 Intrusive units (units 7-12) 654.2.4 Structure 694.3 Phyric and aphyric Hedley intrusions (unit 7) 734.3.1 Detail description 734.3.2 Petrochemistry 784.3.3 Discussion 84PageV4.4 Alteration and mineralization of the French mine 914.4.1 Skarn association with sills and dykes 914.4.2 Endoskarn 924.4.3 Exoskarn 964.4.4 Discussion 102CHAPTER 5.0 CONCLUSIONS 1065.1 Geological Setting of the Hedley gold skarn camp 1065.2 Geological setting of the French mine gold skarn 1095.3 Gold skarn mineralization of the French mine 1115.4 Model for Hedley-type gold skarns 113REFERENCES 115APPENDIX A: Fossil descriptions and ages of microfossils from the Hedley area, south-centralBritish Columbia. 129APPENDIX B: Isotopic analyses (U-Pb zircon, K-Ar biotite hornblende and amphibole, and galenalead) from the Hedley area, south-central British Columbia. 135APPENDIX C: Lithogeochemical analyses from the Hedley area, south-central British Columbia. 145APPENDIX D: Electron microprobe analyses from the Hedley area, south-central BritishColumbia. 167VILIST OF TABLESPageTable 1.1: Production of gold, silver and copper from skarn deposits, Hedley area, south-central BritishColumbia. 2Table 3.1: Table of formations relating the different use of lithologic and formational names in theHedley area, south-central British Columbia. 7Table 3.2: Summary of stratigraphy, chemistry and tectonic setting of the Hedley area, south-centralBritish Columbia. 46Table 4.1: Mineralogy of infiltrational skarn within (endoskarn), and adjacent (exoskarn) to biotiticphyric and aphyric Hedley intrusions, French mine, south-central British Columbia. 99Appendix ATable A. 1: Fossil descriptions and ages of microfossils from the Apex Mountain complex and the NicolaGroup, Hedley area, south-central British Columbia. 131Appendix BTable B. 1: U-Pb analysis of zircon fractions from intrusive and extrusive rocks in the Hedley area, south-central British Columbia. 138Table B.2: K-Ar (biotite, hornblende and amphibole) and U-Pb (zircon) analyses of intrusive rocks in theHedley area, south-central British Columbia. 142Table B.3: Galena-lead isotope Jfl for the Nickel Plate gold skarn and the Copper Mountain copper-gold porphyry deposit, south-central British Columbia. 144Appendix CTable C. 1: Major element and CJPW normative mineralogy of volcanic and intrusive rocks from theHedley area, south-central British Columbia. 147Table C.2: Trace element analyses of volcanic and intrusive rocks from the Hedley area, south-centralBritish Columbia. 153Table C.3: Major element analyses and CIPW normative mineralogy of phyric and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia. 159Table C.4: Trace element analyses of phyric and aphyric Hedley intrusions from the French Mine area,south-central British Columbia. 163Appendix DTable D. 1: Electron microprobe analyses of igneous garnet from minor intrusion near Skwel Kwel PekenRidge, Hedley area, south-central British Columbia. 169Table D.2: Electron microprobe analyses of garnet from the French mine, south-central BritishColumbia. 179vi’PageTable D.3: Electron microprobe analyses of clinopyroxene from the French mine, south-central BritishColumbia. 193Table D.4: Electron microprobe analyses of suiphide minerals from the French mine, south-centralBritish Columbia. 205Table D.5: Electron microprobe analyses of gold from the French mine, south-central British Columbia. 206Table D.6: Electron microprobe analyses of telluride minerals from the French mine, south-centralBritish Columbia. 207VuLIST OF FIGURESPageFigure 1.1: Regional geology of the Hedley gold skarn camp, south-central British Columbia (modifiedfrom Ray et al., 1988). 4Figure 3.1: Sample locations are plotted for: whole rock chemical analyses (W: Table C. 1 and C.2),microfossils (F: Table A. 1), zircon U-Pb dates (Z: Table B. 1, Fig. 3.10), biotite K-Ar dates (B:Table B.2), hornblende K-Ar dates (H: Table B.2), amphibole K-Ar dates (A: Table B.2), andmineral deposits. 15Figure 3.2: Total alkali vs. silica diagram (TAS: compositional fields defined by Cox et at., 1979) withplot ofvolcanic rocks from the Hedley area, south-central British Columbia. 18Figure 3.3: Total alkali vs. silica plot (TAS: Irvine and Baragar, 1971) of rocks from the Hedley area,south-central British Columbia. 18Figure 3.4: Total alkali, total iron, magnesium diagram (AFM: Irvine and Baragar, 1971) of subalkalicrocks from the Hedley area, south-central British Columbia. 19Figure 3.5: Titanium, zirconium, yttrium diagram (Pearce and Cann, 1973) of rocks from the Hedleyarea, south-central British Columbia. 19Figure 3.6: Niobium, zirconium, yttrium plot (Nb*2 - Zr/4- Y: Meschede, 1986) of rocks from theHedley area, south-central British Columbia. 20Figure 3.7: MORB normalized (see Pearce, 1983, for normalizing factors) trace element plot of rocksfrom the Hedley area, south-central British Columbia compared to modern day calcalkalineisland arc basalts (triangle = data from Sun, 1980). 20Figure 3.8: Chemical composition of intrusive rocks from the Hedley area, south-central BritishColumbia plotted on normative diagram (Streckeisen and Lemaitre, 1979). 27Figure 3.9: Total alkali vs. silica diagram (compositional fields defined by Middlemost, 1985) of intrusiverocks from the Hedley area, south-central British Columbia. Squares = Hedley intrusions;triangles = Mount Riordan stock; asterisks = Cahill Creek pluton. 27Figure 3.10: U-Pb concordia diagrams of zircon analyses from intrusive and extrusive rocks in the Hedleyarea, south-central British Columbia (J. Gabites, written communication, 1993). 28Figure 3.11: K20vs. Si02 diagram (Gill, 1981) for the Skwel Peken formation, Hedley area, south-central British Columbia. 32Figure 3.12: Compositions of garnet expressed as the end members: AL (almandine) + PY (pyrope), SP(spessartine), and GR (grossularite) + AD (andradite) from a rhyolite dyke near Skwel PekenRidge, Hedley area, south-central British Columbia. 32Figure 3.13: Schematic cross-sections of the eastern rifted margin of the Nicola basin during formation ofmajor units in the Hedley area, south-central British Columbia. 39Figure 3.14: Cross-section A-A’ through Stemwinder and Nickel Plate Mountain (see Fig. 1.1 for sectionlocation) showing Hedley anticline and reverse faults related to Lower Jurassic to Cretaceous (?)compression. 40ixFigure 3.15: Stereoplots of structural measurements from the Nicola Group, Hedley area, south-centralBritish Columbia. 41Figure 3.16: Galena lead isotopes (Table B.3) from the Nickel Plate gold skarn and Copper Mountaincopper-gold porphyiy deposit, south-central British Columbia. 44Figure 3.17: Conodont ages from sedimentary formations in the Nicola Group, Hedley area, south-centralBritish Columbia. 50Figure 3.18: U-Pb and K-Ar dates for intrusive and extrusive rocks in the Hedley area, south-centralBritish Columbia. 50Figure 4.1: Local Geology of the French - Good Hope mine area, south-central British Columbia. 56Figure 4.2: East- west cross-sections A-A’ and B-B’ (see Fig. 4.1 for section locations) through theFrench- Good Hope mine area, south-central British Columbia. 57Figure 4.3: Stereoplots of structural measurements from the French- Good Hope mine area, south-centralBritish Columbia 72Figure 4.4: Detailed geology of the French Mine, south-central British Columbia. 74Figure 4.5: North - south cross-section A-A’ (see Fig. 4.4 for section location) through the French mine,south-central British Columbia. 75Figure 4.6: Plot of sample locations for whole rock chemical analysis (W: Tables C.3 and C.4). 82Figure 4.7: Chemical composition of Hedley intrusions (unit 7) French Mine area, south-central BritishColumbia. 83Figure 4.8: Total alkali vs. silica plot (compositional fields defined by Middlemost, 1985) of phyricHedley intrusions from the French mine area, south-central British Columbia. 83Figure 4.9: Si02 vs. log (Zr/Ti02)plot (Winchester and Floyd, 1977) of hornblende phyric and aphyricHedley intrusion from the French mine area, south-central British Columbia. 85Figure 4.10: Total alkali vs. silica plot (TAS: Irvine and Barager, 1971) of phyric and aphyric Hedleyintrusions from the French mine area, south-central British Columbia. 85Figure 4.11: AFM diagram (Irvine and Baragar, 1971) of subalkalic phyric and aphyric Hedley intrusionsfrom the French mine area, south-central British Columbia. 86Figure 4.12: Triaxial TiIlOO - Zr - *3 plot (Pearce and Cairn, 1973) of phyric and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia. 86Figure 4.13: Triaxial TiJlOO - Zr - Sr12 plot (Pearce and Cann, 1973) of phyric and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia. 87Figure 4.14: Ternary diagram showing the composition of garnet from skarn at the French mine, south-central British Columbia. 94Figure 4.15: Ternary diagram showing the composition of clinopyroxene from skarn at the French mine,south-central British Columbia. 94IPageFigure 4.16: Schematic section showing skarn alteration within, and adjacent to phyric and aphyricbiotitic Hedley intrusions, French Mine, south-central British Columbia. 98xlLIST OF PLATESPageFrontispiece: Aerial photograph (looking north; 1985) of the Hedley area, south-central BritishColumbia. Hedley township is in the lower left foreground on the north side of the SimilkameenRiver and Highway 3, which transects the map area. N = Nickel Plate mine (before open pit); F =French mine; G = Good Hope mine. Distance from French mine to Nickel Plate is about 5 km. ii.Plate 3.1: Copperfield breccia of angular to rounded clasts of limestone in a limey-tuffaceous matrix(unitS: Fig. 1.1). Outcrop is along Whistle Creek road, 4 km west of Hedley township. 14Plate 3.2: Photomicrograph (transmitted light, crossed polars, field of view = 1.25 mm) of plagioclaseaugite phyric andesite tuft Whistle formation (unit 6: Fig. 1.1). 14Plate 3.3: Whistle formation andesite lapilli tuff containing clasts of hornblende phyric andesite-basalt(unit 6: Fig. 1.1). Outcrop is along the Whistle Creek road, 4 km west of Hedley township. 16Plate 3.4: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of plagioclasehornblende phyric quartz diorite of the Stemwinder pluton. Plagioclase and poikilitic hornblendecrystals are strongly zoned (unit 7: Fig. 1.1). 16Plate 3.5: Bleached hornblende phyric quartz diorite cut by fractures with calcite + garnet + pyroxeneenvelopes (unit 7: Toronto stock, Fig 1.1). Outcrop is along Princeton portal road, Nickel Platemountain. 22Plate 3.6: Nickel Plate sill complex (unit 7) intruding limestones and siltstones of the Hedley formation(unit 2: Fig. 1.1). Note that the sills (brown) are thin where the limestones and siltstones (grey)are thinly bedded (middle-right of photograph) and thick where the limestones and siltstones arethickly bedded (middle of photograph). Photograph was taken looking north from Highway 3,one kilometre east of Hedley township. 22Plate 3.7: Hedley quartz diorite sill (unit 7) intruded into limestone of the Hedley formation (unit 2: Fig.1.1). Note irregular wavy lower contact of sill. Outcrop is along the Princeton portal road, NickelPlate mountain. 24Plate 3.8: Hedley quartz diorite sill (unit 7) in siltstones and limestone of the Hedley formation (unit 2:Fig. 1.1). Note the bleached white clasts of Hedley quartz diorite (globular peperite) within greylimestone near the sill contact. Outcrop is along the Princeton portal road, Nickel Platemountain. 24Plate 3.9: Hediley quartz diorite sill (unit 7) in siltstone and limestone of the Hedley formation (unit 2,Fig. 1.1). Cooling joints perpendicular to sill contacts are prominent. Outcrop is along thePrinceton portal road, Nickel Plate mountain. 25Plate 3.10: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of hornblendeporphyritic Hedley diorite sill (unit 7: Fig. 1.1). Hornblende crystals are zoned. 25Plate 3.11: Photomicrograph (transmitted light, crossed polars, field ofview = 5.0 mm) of quartzporphyry (unit 12: Fig. 1.1). Embayed quartz phenocrysts occur in a fine grained quartzofeldspathic matrix. 34Plate 3.12: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of dacitic ashtuff from lower unit of the Skwel Peken formation (unit 13a: Fig. 1.1). 34xl’Plate 3.13: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of andesitecrystal tuff from the upper unit of the Skwel Peken formation (unit 13b: Fig. 1.1). 36Plate 3.14: Photomicrograph (transmitted light, crossed polars, field of view = 0.625 mm) of an igneousgarnet from a rhyolite intrusion near Skwel Kwell Peken Ridge (minor intrusion: not shown atscale ofFig. 3.1). 36Plate 3.15: Asymmetric minor fold within thinly bedded siltstones of the Hedley formation (unit 2: Fig.1.1). The axial plane strikes northeast and dips steeply west. Photograph was taken lookingnorth, approximately 1 km north of Hedley township along Bradshaw creek. 43Plate 3.16: Duplex like structures within Chuchuwayha formation (unit 3: Fig. 1.1) probably related toLower Jurassic thrust faults. Photograph was taken looking north from Highway 3 at Hedleytownship. 43Plate 4.1: Photoniicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of silistone fromthe Apex Mountain complex cut by irregular veinlets of mosaic quartz (unit 1: Fig. 4.1). Veinletsmay represent dewatering structures formed during sediment compaction and diagenesis. 59Plate 4.2: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 nun) of biotite +cordierite altered argillite and siltstone from the Apex Mountain complex (unit 1: Fig. 4.1). 59Plate 4.3: Photomicrograph (transmitted light, crossed polars, field of view = 1.25 mm) of cordieriteporphyroblasts in siltstones of the Apex Mountain complex (unit 1: Fig. 4.1). Cordierite isanhedral to subhedrai and contains numerous inclusions of biotite, quartz and rarely garnet; somegrains exhibit sector twinning. 60Plate 4.4: Photomicrograph (transmitted light, crossed polars, field of view = 1.25 mm, field of view =5.0 mm) of clear to pink subhedral garnet crystals in siltstone from the Apex Mountain complex(unit 1: Fig. 4.1). Garnet is surrounded by biotite and quartz. 60Plate 4.5: Photomicrograph (transmitted light, crossed polars, field ofview = 5.0 mm) of hornblendephyric andesite to basaltic volcanic rock from the Apex Mountain complex (unit 1: Fig. 4.1).Hornbiende phenocrysts are partly altered to brown biotite and ilmenite. 62Plate 4.6: Photomicrograph (transmitted light, crossed polars, field ofview = 5.0 mm) of chert pebbleconglomerate from the Apex Mountain complex (unit 1: Fig. 4.1). Recrystallized chert ciast is ina fine grained matrix of quartz, feldspar, biotite, tremolite-actinolite, muscovite, chlorite andopaque minerals. 62Plate 4.7: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of chert from theApex Mountain complex (unit 1: Fig. 4.1). Spherical microcrystalline quartz grain (<3 mmacross) may represent radiolarian tests. 63Plate 4.8: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 nun) of serpentinizedultramafic (durute) from the Apex Mountain complex (unit 1: Fig. 4.1). Sheared and fracturedolivine is altered to chrysotile and magnetite. 63Plate 4.9: Photograph of Copperfield breccia at the French mine (unit 5: Fig. 4.1). The limey tuffaceousmatrix is altered to garnet and the limestone clasts are altered to marble and/or wollastonite. Thisskam apparently is a metamorphic reaction skarn formed by the intrusion of the adjacent CahillCreek pinion (unit 10). 66xl”PagePlate 4.10: Photomicrograph (transmitted light, crossed polars) of hornblende granodiorite from theCahill Creek pluton (unit 10: Fig. 4.1). Hornblende crystals are altered to brown biotite, chlorite,carbonate and sphene. 66Plate 4.11: Quartz + actinolite + epidote ± molybdenite ± scheelite veins related to the aplite phase of theCahill Creek pluton (unit 10: Fig. 4.1). Veins cross-cut garnet skarn related to intrusion of theolder Hedley intrusions (unit 7); the protolith to the garnet skarn is Hedley formation limestones(unit 2). Photograph is from the southern end of the Good Hope open pit. 68Plate 4.12: Rhyolite porphyry (unit 12: Fig. 4.4) containing phenocrysts of quartz, plagioclase andorthoclase in an aphanitic groundmass. Photograph is along the upper haulage track west of the3920 Level adit. 68Plate 4.13: Photomicrograph (transmitted light, crossed polars, field ofview = 5.0 mm) of quartz rhyoliteporphyry (unit 12: Fig. 4.4). 70Plate 4.14: Quartz diorite of the Hedley intrusions contains numerous malic xenoliths and forms a stocklike body at the French mine (unit 7: Fig. 4.4). Photograph is of outcrop along road 50 mnorthwest of the Cariboo adit, French mine. 70Plate 4.15: Photomicrograph (transmitted light, crossed polars, field ofview = 5.0 mm) of hornblendephyric Hedley intrusion (unit 7: Fig. 4.4). Euhedral hornblende crystals are partly replaced byfine grained biotite. 76Plate 4.16: Photograph across aphyric - hornblende phyric contact (dashed lines), Hedley intrusion (unit7: Fig. 4.4). Contact is gradational over 10’s of centimetres. Outcrop is along upper haulage trackimmediately east of the “open” stopes. 76Plate 4.17: Aphyric Hedley sills (unit 7: Fig. 4.4) enveloped by a 1cm rim of structureless Hedleyformation siltstone (unit 2). Note the irregular wavy sill contact. Outcrop is along upper haulagetrack immediately west of the 3920 Level adit. 77Plate 4.18: Possible globular peperite along contact of Hedley formation siltstone (unit 2: Fig. 4.4) andaphyric Hedley sill (unit 7). Exposure is on the back of the Granby adit, approximately 75 metresfrom the portal. 77Plate 4.19: Photomicrograph (transmitted light, crossed polars, field ofview = 5.0 mm) of flow bandedaphyric Hedley sill (unit 7: Fig. 4.4). Sample is from lower stope of the French mine. 79Plate 4.20: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of quenched,glassy, aphyric Hedley sill (unit 7: Fig 4.4) with well developed perlitic cracks. Sample is fromlower stope, French mine. 79Plate 4.21: Photomicrograph (transmitted light, crossed polars, field of view 5.0 mm) of quenchedaphyric Hedley sill (unit 7: Fig. 4.4). These radiating splays of acicular plagioclase crystals witha common nucleation point are called “bow-tie” texture (Lofgren, 1974). Sample is from lowerstope, French mine. 80Plate 4.22: Photomicrograph (transmitted light, crossed polars, field ofview = 5.0 mm) of aphyricHedley sill (unit 7: Fig. 4.4). Plagioclase crystals have altered glass cores. Such textures aredescribed as “belt-buckle” texture (Bryan, 1972). Sample is from lower stope, French mine (Fig.4.5). 80xivPlate 4.23: Photomicrograph (transmitted light, crossed polars, field ofview = 1.25 mm) of mosaicquartz vesicles and microveinlets (on right) in aphyric Hedley sill (on left:: unit 7, Fig. 4.4).Sample is from lower stope, French mine (Fig. 4.5). 81Plate 4.24: Thin centimetre scale aphyric basalt sill (unit 7: Fig. 4.4) within structureless Hedleyfonnation siltstone (unit 2). Photograph is from lower stope in the French mine (Fig. 4.5). 81Plate 4.25: Microveinlets with successive mineralogical envelopes of pale green clinopyroxene and pinkorthoclase cross-cutting brown biotite altered aphyric Hedley intrusion (unit 7: Fig. 4.4). Notewhere fracture density is high, individual envelopes encroach on each other to form massiveorthoclase + clinopyroxene endoskarn. Sample is from waste dump, French mine. 95Plate 4.26: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of isotropiceuhedral garnet overprinting clinopyroxene skarned Hedley formation siltstone (unit 2: Fig. 4.4).Sample is from lower stope, French mine (Fig. 4.5). 95Plate 4.27: Photomicrograph (transmitted light, crossed polars, field of view = 1.25 mm) of sectortwinned, optically zoned anisotropic garnet (<2 mm). The anisotropic nature of these garnetsmay be caused by minute amounts of water in their crystal structure. Protolith of this sample isuncertain, but is likely Hedley formation limestone (unit 2: Fig. 4.4). Sample is from lower stope,French mine (Fig. 4.5). 100Plate 4.28: Photomicrograph (transmitted light, field of view = 1.25 mm) of isotropic subhedral toeuhedral garnet with calcite + silica + vesuvianite infihling growth zones parallel to the crystalmargin. Protolith of this sample is likely Hedley formation limestone (unit 2: Fig. 4.4). Sample isfrom the lower stope, French mine (Fig. 4.5). 100Plate 4.29: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of optically zonedvesuvianite crystals in a vein cross-cutting garnet ± clinopyroxene skarn. Protolith of this sampleis likely Hedley formation limestone (unit 2: Fig. 4.4). Sample is from the lower stope, Frenchmine (Fig. 4.5). 101Plate 4.30: Photomicrograph (reflected light, field of view = 0.3 00 mm) of chalcopyrite exsolutionlamellae in bornite infilling vugs between garnet crystals. Protolith of the sample is likely Hedleyformation limestone (unit 2: Fig. 4.4). Sample is from the waste dump, French mine. 101Plate 4.31: Photomicrograph (reflected light, field of view = 5.0 mm) of gold (Au: Au7993,joseite (J),bismuthinite (B), actinolite (A), and calcite (C) infilling vugs between garnet (G) crystals.Protolith of the sample is Hedley formation limestone (unit 2: Fig. 4.4). Sample is from lowerstope, French mine (Fig. 4.5). 103xvACKNOWLEDGMENTSI would like to thank those from the Department of Geological Sciences, The University ofBritish Columbia (UBC), from the British Columbia Geological Survey Branch (BCGS) of the B.C.Ministry of Energy, Mines and Petroleum Resources and from industry that I have come in contact withover the last few years who have generously shared their ideas and time with me. In particular, I wouldlike to thank Dr. Gerry Ray (BCGS) and Dr. Cohn Godwin (UBC). Much of the data and many of theideas presented here were a result of a regional mapping program I had the opportunity to work on withGerry. Cohn supervised, edited and re-edited my thesis and put up with my antics over the too long periodit took to finish this project. I would also like to thank Anne Pickering and Ian Webster for help in and outof the field, Janet Gabites, Peter van der Hayden and Don Murphy for the U-Pb zircon analyses, and MattiRaudsepp for the electron microprobe analyses. My friends Craig, Andy, Wendy and Tracy are thankedfor offering welcome diversions and getting me through those angst ridden times. Finally, I would like tothank my parents for their unconditional support and encouragement.Field and financial support for this study was generously provided by International CoronaCorporation (now Homestake Canada Inc.), British Columbia Geological Survey Branch of the B.C.Ministry of Energy, Mines and Petroleum Resources, A.E. Aho Scholarship and a G.R.E.A.T Award fromthe Science Counsil of B.C. Cambria Geological Ltd. provide a place from which to work and use ofsoftware and plotting equipment during writing.1GEOLOGICAL SETTING OF THE HEDLEY GOLD SKARN CAMP WITH SPECIFICREFERENCE TO THE FRENCH MINE, SOUTH-CENTRAL BRITISH COLUMBIACHAPTER 1.0 INTRODUCTIONHedley gold camp in south-central British Columbia is 240 km east of Vancouver and 40 kmsoutheast of Princeton (inset, Fig. 1.1; NTS Maps 92HJ8E and 82E/5W; centered near 49° 21’ N, 1200 05’W). Access is by a number of gravel roads off Highway 3, which passes through the middle of the studyarea.The camp is the second largest gold producer in the province and the largest gold skarn inCanada. From the period 1902 to 1955 about 51 million grams of gold were produced from four goldbearing skarn deposits (Table 1.1, Fig. 1.1). Over 95% of this came from the Nickel Plate and Mascotmines, which worked a large skarn deposit centered on Nickel Plate mountain. Early studies of thesedeposits include: Camsell (1910), Warren and Cununings (1936), Warren and Peacock (1945), Billingsleyand Hume (1941), Dolmage and Brown (1945), Lee (1951) and Lamb eta!. (1957). Bostock (1930, 1940a,1940b) completed the first regional mapping of the camp.Renewed interest in the Nickel Plate deposit took place in the early 1980’s following increasedgold prices (Simpson and Ray, 1986). The Nickel Plate mine was reopened by Mascot Gold MinesLimited (now Corona Corporation) in August 1987 as a large tonnage low grade open pit gold deposit.Metals recovered from 1987 to 1990 total 7 145 kg of gold and 7 168 kg of silver (Table 1.1). Ettlinger eta!. (1992) examined skarn evolution and hydrothermal characteristics of the Nickel Plate deposit.The geology, geochemistry and structural setting of the Hedley gold skarns were recentlyexamined by the British Colombia Geological Survey Branch (Ray et a!., 1986, 1987, 1988, 1993; Rayand Dawson, 1994). This work is summarized in Chapter 3.0.Table1.1:Productionof gold,silverandcopperfromskarndeposits,Hedleyarea,south-centralBritishColumbiaDepositOremilledGold(kg)Silver(kg)Copper(tonnes)Reference’(twines)29839007236358619019417064161981a18571NANAb69371707NAaNickel Plate1904-1963Nickel Plate1987-1993HedleyMascot1936-1949NickelPiatetotal10839277672145868981a,bFrench29450786NANAa1950-1955French3562055045NAa1957-1961French44382613520a1982-1983Frenchtotal69508136220a1.References:a=BCEMPRMINFILE; b=HomestakeCanadaInc.(GregLang,writtencommunication,1994);cNationalMineralInventoty(NMI92H18-Au3).180Table1.1:Productionofgold,silver andcopperfromskarndeposits,Hedleyarea,south-cent.ralBritishColumbia(continued)....DepositOremilledGold(kg)Silver(kg)Copper(tonnes)Reference’(tonnes)14934241684716NANAa89NANAc771190.6aCanty1939-41GoodHope1946-1948GoodHope1982GoodHopetotal111151661190.6a,cTOTAL:109213936875861671001.6a,b,c4Figure 1.1: Regional geology of the Hedley gold skarn camp, south-central British Columbia (modifiedfrom Ray et a!., 1988). Sills and dykes are not shown at this scale. Inset map shows Hedley campto be in the Intermontane Belt (Monger et aL, 1982). Map units are: 1 = Apex Mountaincomplex, 2= Hedley formation, 3 = Chuchuwayha formation, 4= Stemwinder formation, 5 =Copperfield breccia, 6= Whistle formation, 7= Hedley intnisions, 8= Bromley batholith, 9=Mount Riordan stock, 10 = Cahill Creek pluton, 11 = Lookout Ridge pluton, 12 = Rhyoliteporphyry, 13a = Skwel Peken formation (lower felsic unit), 13b = Skwel Peken formation (upperintennediate unit). Mineral deposits (crossed shovel and pick) are: 1 = Nickel Plate mine, 2 =French mine, 3 = Canty mine, 4= Good Hope mine, 5 Banbury mine, 6= Peggy mine. Linetypes are: thick continuous = faults, medium continuous = geological contacts, thin continuous =rivers, long-short dash = Highway 3, short dash = gravel roads.5CHAPTER 2.0 REGIONAL GEOLOGYHedley gold camp lies within Quesnellia in the Intermontane Belt of the Canadian Cordillera(inset, Fig. 1.1). Quesnellia, an accreted terrane, comprises Paleozoic to Jurassic marine volcanic andsedimentary rocks, and comagmatic intrusions formed in island arc and marginal basin enviromnents(Monger et a!., 1982), In southern British Columbia, the Late Triassic Nicola Group lies west of, and restswith depositional unconformity on, the deformed Paleozoic Harper Ranch Group (Monger, 1985). TheHarper Ranch Group is correlative with the Apex Mountain complex in the Hedley area (Milford, 1984).Late Triassic subduction of the Pennsylvanian to Triassic Cache Creek Group resulted ininitiation of the Nicola arc (Monger, 1985). Rocks of this arc are dominantly Late Triassic Nicola Group,which has been divided into three volcanic facies and one sedimentary facies (Preto, 1979; Monger, 1985,1989; Mortimer, 1987).The sedimentary facies in the Hedley area, however, probably formed in a back-arc basin east ofthis arc (Monger, 1985). Sedimentary rocks consist of Upper Triassic Carnian to Norian clastic sediments,limestone and tuff They are intruded by synsedimentary sills, dykes and stocks.6CHAPTER 3.0 GEOLOGY OF THE HEDLEY GOLD SKARN CAMP3.1 IntroductionHedley gold camp is underlain by middle to late Paleozoic Apex Mountain complex, sedimentaryfãcies of the Late Triassic Nicola Group, and Middle Jurassic Skwel Peken formation. Late Triassic toTertiary intrusive rocks ranging from gabbro to rhyolite have intruded the above section (Fig. 1.1). Table3.1 outlines the stratigraphic names used here. These names are related to those in Ray and Dawson(1994).Whole rock compositions (53 samples) of intrusive and extrusive rocks were measured to classiI’them chemically and compare their trends to those in known tectonic settings. Tables C. 1 and C.2presents major, minor and trace element chemistry along with their calculated CIPW (Cross, Iddings,Pirsson and Washington) normative mineralogy. Sample locations are plotted on Figure 3.1.Conodonts extracted from limestone units in the Nicola Group and the underlying ApexMountain complex constrain the age of the various sedimentary units. Samples, located on Figure 3.1,were identified by M.J. Orchard and E.C. Prosh (written communications, 1988), Geological Survey ofCanada (Table A. 1).U-Pb analyses of zircons from four intrusive rocks and one volcanic rock (Table B. 1; located inFig. 3.1), and previously published K-Ar (biotite, hornblende and amphibole) and U-Pb (zircon) analyses(Table B.2; located in Fig. 3.1) constrain the timing of magmatic events in the Hedley area. U-Pb data inTable B. 1 are plotted on concordia diagrams (Fig. 3.10).Lead isotope analyses of galena from three samples within the Nickel Plate open pit are in TableB.3 and plotted on conventional Pb-isotope diagrams in Figure 3.16. These data, compared to threesamples from the Copper Mountain copper-gold porphyry gold deposit, help constrain the origin ofhydrothermal fluids responsible for gold skarn mineralization.Table3.1:TableofformationsrelatingthedifferentuseageoflithologicandformationalnamesintheHedleyarea,south-central BritishColumbia.FossilagesandradiometricdatesarelistedandreferencedinTablesA.1,B.1andB.2.RayandDawson(1994)Thispaper(seeFig.1.1)Date1 orAge2(Bulletin87)MiddleJurassic(163-187Ma)Unit15:SkwelPekenformationUnit14:QuartzporphyzyUnit13:LookoutRidgeplutonUnit12:CahillCreekplutonUnit13:SkwelPekenformation—------IntrusiveContactUnit12:RhyoliteporphyryUnit11:LookoutRidgeplutonUnit10:CahillCreekpluton<187±9MaZ(Fig.3.lOf)-Allenianoryounger154.5+81-43MaZ(Fig.3.lOe)-Kimmeridgian164.5±4.8Mab(TableB.2)-Callovian168.8±9.3MaZ(Fig.3.lOd)-Bathonian159.9±2.9to174.5±5.2(TableB.2)-OxfordiantoBathonian153.4±4.6to161.3±1b(TableB.2)-KimmeridgiantoOxfordianEarlyJurassicUnit11:MountRiordanstock(187-208Ma)LateTiiassic(208-230Ma)Unit10:BromleybatholithUnit9:Hedleyintrusions----------IntrusiveContactUnit9:MountRiordanstockUnit8:Bromleybatholith----------IntrusiveContactUnit7:Hedleyintrusions194.6±1.2MaZ(Fig.3.lOc)-Pliensbachian193.0±1.0MaZ(TableB.2)-ToarciantoPliensbachian185.7±2.8to188.1±5.8Ma1(TableB.2)-AlleniantoToarcian173.4±4.7to180.9±5.4Mab(TableB.2)-BatholniantoBajocian<215.4±4MaZ(Fig.3.lOb)-Norianoryounger175.0±5.4to195.0±9.0Maa(TableB.2)-BatholniantoPliensbachian----------IntrusiveContact——----1.Z=u-Pbzirconanalysis;h=K-Arhomblendeanalysis;b=K-Arbiotiteanalysis;aK-Aramphiboleanalysis;=fossil.2.TimescaleusedisafterArmstrongetat.,1988.-JTable3.1:TableofformationsrelatingthedifferentuseageoflithologicandformationalnamesintheHedleyarea,south-central BritishColumbia(continued)....RayandDawson(1994)Thispaper (seeFig.1.1)DateorAge2(Bulletin 87)Unit7:WhistleformationUnit6:WhistleformationUnit3:FrenchMineformationUnit5:CopperfieldbrecciaLateCarniantoEarlyNorian(TableA.1)Unit5:StemwinderformationUnit 4:StemwinderformationLateCamiantoLateNorian1’(TableA.1)Unit6:ChuchuwayhaformationUnit3:ChuchuwayhaformationEarlytoMiddle Norian(TableA.1)Unit4:HedleyformationUnit2:HedleyformationEarlytoMiddleNoriaJ (TableA.1)------—Unconfonnity?----------MiddletoLateUnit8:UncertainpositionUnit 1:ApexMountaincomplexOrdovician,EarlytoLateDevonian,PaleozoicMiddletoLateTriassiJ(TableA.1)Unit2:OregonClaimsformationUnit1: ApexMountaincomplex93.2 Apex Mountain complex (unit 1)The Middle to Late Paleozoic Apex Mountain complex rocks (unit 1: Table 3.1) are the oldestand most strongly deformed in the Hedley area. They crop out (Fig. 1.1) along and east of Cahill Creeknorth of the Similkameen River, east of the Cahill Creek pluton south of the Similkameen River, and in asmall fault slice west of the Bradshaw fault. The complex consists of: (i) mafic volcaniclastic rocks, (ii)thin bedded siltstone, (iii) limestone, (iv) argillite, (v) chert, and (vi) greenstone.Mafic volcaniclastic rocks are exposed (Fig. 1.1) east of the Nickel Plate mine along CahillCreek, in the vicinity of the Good Hope and French mines, and in a small exposure west of the Bradshawfault. This unit consists of massive to weakly laminated dark green to black ash tuff with lesser amounts oflapilli tuff. In areas of poor exposure, these tuffs are difficult to distinguish from tuffs in the youngerWhistle formation. However, tuffs in the Apex Mountain complex are darker, and contain rare grains ofmosaic quartz and local interbeds of chert pebble conglomerate. The tuffs have a crystal assemblage ofhornblende (<10 mm), augite (<1 mm) and plagioclase (<4 mm) within an ash matrix. Lapilli are mainlyhomolithic, but rare clasts of limestone and chert occur.Thin bedded siltstone is associated with minor argillite and rare chert pebble conglomerate. Itcrop out (Fig. 1.1) northwest of Winters Creek and west of the Similkameen River. The siltstones consistof broken and rounded grains of mosaic quartz and feldspar, with minor clay, sericite, chlorite, titaniteand opaque minerals. Near the contact of the Cahill Creek pluton these sedimentary rocks are locallyhornfelsed to biotite + cordierite + muscovite + garnet. Subparallel alignment of red biotite and muscovitein argillaceous layers impart a moderate foliation.Limestone is relatively rare but widespread throughout the Apex Mountain complex. It occurs asdisrupted blocks or as thin horizons within mafic volcaniclastic rocks west of the French mine (Fig. 1.1).The disrupted blocks are <10 m in diameter and probably olistoliths. Bedding in the fine grained maficvolcaniclastic rocks that surround these blocks is often contorted; this suggests the tuffs wereunconsolidated when the limestone blocks were deposited. Thicker limestone units occur north of themouth of Winters Creek, and between Larcan and Paul Creek south of the Similkameen River. The10limestone north of Winters Creek forms a large cliff that is recrystallized to marble, locally contains skarnand is malachite stained. South of the Similkameen River the limestone, also recrystallized to marble, isup to 60 m thick and traceable for over 1 km along strike. Fossils from limestone beds throughout thestratigraphy [based on limited sampling during this study (Table A. 1, Fig. 3.1) and previous work(Milford, 1984)] were Ordovician, Early to Late Devonian, Carboniferous and Middle to Late Triassic.Rocks in the western part of the complex are younger, but structurally underlie older rocks in the east(Milford, 1984).Argillite is massive to weakly foliated. It crops out east of Winters creek. This unit containsminor interbeds of siltstone and rare beds of chert.Chert occurs predominantly south of Bradshaw Creek where it is interbedded with greenstone. Inthin section it consists of fine grained quartz with minor tremolite-actinolite, chlorite, biotite, epidote,titanite, carbonate, plagioclase and opaques.Greenstone forms discontinuous units up to 100 m thick throughout the complex, and as thickerbodies at the headwaters of Bradshaw Creek where they are intimately associated with coarse grainedhornblende gabbro and diorite. From thin sections, the hornblende phenociysts (<1 cm) are partiallyreplaced by chlorite, tremolite-actinolite and minor biotite. The altered matrix consists of plagioclase,chlorite, epidote, biotite, sericite, carbonate, titanite, rutile and opaque minerals.3.3 Nicola Group (units 2 to 6)Sedimentary facies of the Late Triassic Nicola Group can be divided informally into foursedimentary units--Hedley formation, Chuchuwayha formation, Stemwinder formation and Copperfieldbreccia--and the volcaniclastic Whistle formation. The shallow water Hedley formation, the intermediatedepth Chuchuwayha formation and the deep water Stemwinder formation are facies equivalents,representing deposition across a westerly sloping and fault controlled basin margin. Nicola Groupunconformably overlies the Apex Mountain complex elsewhere in southern British Columbia. However, in11the Hedley area the relationship at this contact is not everywhere clear as it is commonly faulted, intrudedby the Cahill Creek pluton, or poorly exposed. Collapse of the basin in Late Triassic time is marked bydeposition of the Copperfield breccia followed by volcaniclastic and pyroclastic deposits of the Whistleformation.Hedleyformation (unit 2) is best exposed north of the Similkameen River, between the Bradshawand Cahill Creek faults, where it is at least 500 m thick (Fig. 1.1). East of the Cahill Creek fault, the unitabruptly thins to less than 50 m thick where it is preserved at the Good Hope and French mines. South ofthe Similkameen River, the unit is bounded by the Bradshaw fault or overlain by the Whistle formation(western map area of Fig. 1.1), and intruded by the Cahill Creek pluton (eastern map area).The formation comprises a mixed sequence of clastic sedimentary rocks and limestone. Finelylaminated white to beige siltstones are interbedded with minor black argillite that locally display gradedbeds, scour and fill structures, and flames and cross-bedding that indicate deposition by westerly directedpaleocurrents. Laminated to massive beds of white to grey limestone are generally <10 m thick and formboth continuous and discontinuous horizons within the siltstones. Some beds, such as the Sunnysidelimestone described by Bostock (1930), are up to 75 m thick and can be followed along strike for over 1km. Diagenesis and metamorphism have destroyed many of the primary textures and structures in thelimestones making interpretation of their depositional environment difficult. Some beds locally containcrinoid ossicles, solitary corals, bivalve fragments and belemnites. Conodonts from limestones in this unitare Late Triassic and Early to Middle Norian (Table A. 1, Fig. 3.1). Interbedded polymictic conglomerate,grit and limestone crop out near the base of the Hedley formation along the southeast slope of Nickel Platemountain. This conglomerate has a maximum thickness of 100 m and can be followed along strike for 1km. It contains subrounded, pebble sized clasts of grey to cream coloured chert and minor limestone,volcanic, argillite and siltstone within a silty calcareous matrix. This unit may represent a fan depositdeveloped along the edge of the Cahill Creek normal fault. Tuffaceous horizons occur near the top of theformation close to the contact with the overlying Whistle formation.12Chuchuwayhaformation (unit 3) forms a wedge shaped unit bounded by the Chuchuwayha faultto the west and the Bradshaw fault to the east (Fig. 1.1). The northern part of this unit is intruded by theLookout Ridge pluton. The unit is a minimum of 1 500 m thick.This formation consists of thin bedded, pale calcareous siltstone, minor black argillite and greyimpure limestone, and rare chert pebble conglomerate. The formation resembles Hedley formation, butlacks thick and extensive limestone beds. Limestone beds in the Chuchuwayha formation are generallyless than 5 m thick and often have graded beds containing chert clasts, broken bivalve shells and crinoidossicles. Conodonts from these limestone beds are Late Triassic and range from Early to Middle Norian(Table A.1, Fig. 3.1).Stemwinderformation (unit 4) is bounded by the Chuchuwayha fault to the east, intruded by theBromley batholith and Lookout Ridge pluton to the north, and by a tongue of the Cahill Creek pluton tothe south (Fig. 1.1). Western exposures are overlain by the Whistle formation. The bottom of theStemwinder formation is not exposed, however the unit is a minimum of 1 500 m thick.The formation consists of thinly bedded black calcareous argillite, lesser amounts of palecalcareous siltstone, and minor dark grey to black impure limestone. A number of sedimentary structures--such as overturned flames, cross-bedding and scour and fill textures preserved in the finely laminatedsediments--indicate deposition by westerly directed paleocurrents. Rare limestone beds, up to 3 m inthickness, often contain graded chert pebbles. Conodonts from these limestone beds are Late Triassic andrange from Late Carnian to Late Norian (Table A. 1, Fig. 3.1). Rare andesite ash tuff occurs near the top offormation close to the contact with the overlying Whistle formation.Copperfield breccia (unit 5) often forms a coherent but discontinuous stratigraphic unit. Locallyit forms several horizons separated by tuffaceous sediments. The unit varies from less than 15 to 200 m inthickness. It is well exposed 4.3 km west of Hedley, south of the Larcan stock, and in the vicinity of theNickel Plate, Good Hope and French mines (Fig. 1.1). This unit was first described by Bostock (1930) andthought to be a tectonic breccia related to a subsidiary splay of the nearby Bradshaw thrust fault(Billingsley and Hume, 1941).13Limestone clasts within a calcareous tuffaceous matrix characterize the Copperfield breccia(Plate 3.1). The clasts are angular to rounded, poorly sorted, boulder to pebble sized, and mainlylimestone. Bivalves and conodonts from a limestone clast were Late Triassic and range from Late Carnianto Early Norian (Table A. 1, Fig. 3.1). Minor clasts include: argillite, siltstone, chert, and felsic tointennediate volcanic and intrusive rocks. The matrix consists of fine grained carbonate, chert, limestone,siltstone and tuffWhistleformation (unit 6) is widespread throughout the Hedley map area (Fig. 1.1). It consists ofthinly bedded tuffaceous siltstone and argillite near its base, but grades up section into massive greenandesitic ash and lapilli tuff, and minor breccia. The unit is a minimum of 1 000 m thick and usually isseparated from underlying formations--Hedley, Chuchuwayha and Stemwinder--by the Copperfieldbreccia.Thin bedded tuffaceous siltstone and argillite overly the Copperfield breccia. Individual beds areoften graded with sharp feldspar rich bases and diffuse argillaceous tops. Rare cross-bedding and obliqueflame structures indicate initial sedimentation in the Whistle formation was by westerly directed turbiditycurrents, similar to the underlying formations. Higher in the stratigraphy, the thin bedded tuffaceoussediment are intercalated with massive to weakly bedded ash tuff. These units gradually grade upwardsinto ash, lapilli and tuffbreccia, which probably represent water settled pyroclastic fall deposits (Cas andWright, 1987).Most of these ash tuffs contain a crystal assemblage of plagioclase (An40), augite and rarehornblende within a fine grained tuffaceous matrix (Plate 3.2). Plagioclase crystals (<2 mm) are subhedralto euhedral and display reverse oscillatory zoning. Augite crystals are subhedral to euhedral (<1 mm).Accessory and trace minerals include quartz, chlorite, carbonate, epidote, titanite and opaque minerals.Lapilli tuff and minor tuffbreccia form extensive, massive units (Plate 3.3). Clasts are mostlyrounded to angular and andesite to basalt in composition. Rare clasts of dacite, siltstone and limestoneoccur.Whole rock analyses of ash tuff from the Whistle formation are mainly basalt with somebordering the andesite fields of the TAS (total alkalis vs. silica) diagram in Figure 3.2 (Cox et al., 1979).14Plate 3.1: Copperfield breccia of angular to rounded clasts of limestone in a limey-tuffaceous matrix(unit 5: Fig. 1.1). Outcrop is along Whistle Creek road, 4 km west of Hedley township.Plate 3.2: Photomicrograph (transmitted light, crossed polars, field of view 1.25 mm) of plagioclaseaugite phyric andesite tufT, Whistle formation (unit 6: Fig. 1.1).15492w:/( \ /I \\ / ., --+W30-- -—--:‘“-r IF-_‘1.I.F 3-\ \ +F24 \\ \ ‘, >e\‘—+W46, \ 7.VancoerKflornetres J(\ Hedley area49’1 7 ) It 49i5Figure 3.1: Sample locations are plotted for: whole rock chemical analyses (W: Table C. 1 and C.2),microfossils (F: Table A. 1), zircon U-Pb dates (Z: Table B. 1, Fig. 3.10), biotite K-Ar dates (B:Table B.2), hornblende K-Ar dates (}{: Table B.2), amphibole K-Ar dates (A: Table B.2), andmineral deposits (crossed shovel and pick: 1 Nickel Plate mine, 2 French mine, 3 = Cantymine, 4 = Good Hope mine, 5 = Banbury mine, 6 = Peggy mine). Line types are: thin continuousrivers, long-short dash = Highway 3, short dash = gravel roads.16Plate 3.3: Whistle formation andesite lapilli tuff containing clasts of hornblende phyric andesite-basalt(unit 6: Fig. 1.1). Outcrop is along the Whistle Creek road, 4 km west of Hedley township.Plate 3.4: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of plagioclasehornblende phyric quartz diorite of the Stemwinder pluton. Plagioclase and poikolitic hornblendecrystals are strongly zoned (unit 7: Fig. 1.1).17They span the alkalic and subalkalic boundaiy on the TAS diagram in Figure 3.3 (Irvine and Baragar,1971). The subalkalic samples plot in the calcailcaline field on a AFM (total alkali, total iron, magnesium)diagram in Figure 3.4 (Irvine and Baragar, 1971).Relatively immobile trace element plots do not clearly define the tectonic environment of theserocks. On the TiJlOO - Zr - *3 diagram in Figure 3.5 (Pearce and Cairn, 1973) the samples plot mainlyin the lAB (island arc basalt) field. On the Nb*2 - Zr14 - Y diagram of Figure 3.6 (Meschede, 1986) thesamples plot mainly in the N- MORB (mid-ocean ridge basalt, normal-type) field; one analysis plots onthe border of the P-MORB field (mid-ocean ridge basalt, plume-type). However, the rocks are enriched inL1LE (large ion lithophile elements: Sr, K, Rb, Ba and Th) similar to modern calcalkaline island arcs(Fig. 3.7: Pearce, 1983). This LILE enrichment can reflect contributions from the subduction zone to themantle wedge during magma generation (Wilson, 1989). Most of the immobile elements (e.g. Nb, Zr, Tiand Y) have low values of about 1 that consequently parallel MORE trends. This indicates that theimmobile elements were not markedly modified by subduction processes.3.4 lledley intrusions (unit 7)Hedley intrusions (unit 7) form dykes, sills and stocks that intrude the Nicola Group and theunderlying Apex Mountain complex. The Aberdeen, Stemwinder, Toronto, Banbuiy, Pettigrew andLarcan stocks (Fig. 1.1) form elongate to round bodies that follow east-west to northwest trendingfractures. The stocks, equigranular in texture, are quartz diorite to gabbro in composition. They arehornblende, plagioclase and rarely augite phyric in a fine grained quartzo-feldspathic groundmass. Dykesand sills have a similar composition to the stocks, but are markedly porphyritic. Dykes, rare compared tosills, mostly follow west-northwest fractures (similar to the stocks). Sills are best developed within theHedley formation and are spatially and temporally associated with gold skarn mineralization. TheStemwinder and Toronto stocks, and the associated sill complex exposed on Nickel Plate mountain, aredescribed below.181715. 10c’J(‘1CFigure 3.2: Total alkali vs. silica diagram (TAS: compositional fields defined by Cox et at, 1979) withplot ofvolcanic rocks from the Hedley area, south-central British Columbia. Circles = Whistleformation tuffs (mainly basalt); crosses = Skwel Peken formation (lower unit tuffs: dacite);diamonds = Skwel Peken formation (upper unit tuffs: andesite).Figure 3.3: Total alkali vs. silica plot (TAS: Irvine and Baragar, 1971) of rocks from the Hedley area,south-central British Columbia. Circles = Whistle formation tuffs; squares Hedley intrusions;triangles = Mount Riordan stock; asterisks = Cahill Creek pluton; crosses = Skwel Pekenformation (lower unit tuffs); diamonds = Skwel Peken formation (upper unit tuffs). Samples aredominantly subalkaline.34 40 60 10 16S1 (t Z)201614=10c’J-aC’-’C35 48 45 50 55 60 65 70 75 80 85S1 (wt Xl19A: Na20 + K20F: FeOM: MgOFigure 3.4: Total alkali, total iron, magnesium diagram (AFM: Irvine and Baragar, 1971) of subaficalicrocks from the Hediley area, south-central British Columbia. Circles = Whistle formation tuffs;squares = Hedley intrusions; triangles = Mount Riordan stock; asterisks = Cahill Creek pluton;crosses = Skwel Peken formation (lower unit tuffs); diamonds = Skwel Peken formation (upperunit tuffs). Samples are dominantly calcalkaline.Zr Y3Figure 3.5: Titanium, zirconium, yttrium diagram (Pearce and Cann, 1973) of rocks from the Hedleyarea, south-central British Columbia. Circles = Whistle formation tuffs; squares = Hedleyintrusions. Most analyses are compatible with an origin within an island arc. One sample ofWhistle formation plots within an ocean floor environment, indicating that it may be more‘primitiv&.Ti / 100tBasoit20vZr / 4Nb * 2Ridge Bsoit — PI.ur’e typeRidge Basoit- Norrut typeyFigure 3.6: Niobium, zirconium, yttrium plot (Nb*2- Zr/4 - Y: Meschecle, 1986) of rocks from theHedley area, south-central British Columbia. Circles = Whistle formation tuffs. The primitive‘nature’ of Whistle formation noted in Figure 3.5, is clear by its plotted position within the fieldfor mid-ocean ridge basalt of the normal type. Note that on this diagram it does not look like ithas volcanic arc characteristics. Thus, it may have a marginal basin affinity..1Figure 3.7: MORB normalized (see Pearce, 1983, for normalizing factors) trace element plot of rocksfrom the Hedley area, south-central British Columbia compared to modem day calcalkalineisland-arc basalts (triangle = data from Sun, 1980). Circles = Whistle formation tuffs; squares =Hedley intrusions; asterisks = Cahill Creek pluton; crosses = Skwel Peken formation (lower unittuffs); diamonds = Skwel Peken formation (upper unit tuffs). Note common enrichment in LILE(large ion lithophile elements: Sr to Th).PLate ALkaLine Basaltte ThoteiitelOSr K B Th 1 Nb Ce P Zr HF Sr Ti I t’b21Stemwinder stock, about 2 km north of Hedley township (Fig. 1.1), forms a subhorizontal body 2km long by <1 km wide that is elongate in a west-northwest direction. The mainly quartz diorite stock ismassive, medium grained and equigranular to weakly porphyritic. It consists of plagioclase (An),hornblende, microcline, orthoclase, quartz and minor augite (Plate 3.4). Plagioclase crystals are subhedralto euhedral (<4 mm) and show normal and reverse oscillatory zoning. The poikilitic hornblende crystalsare subhedral to euhedral (<3 mm). Rare augite phenocrysts are anhedral to subhedral (<1 mm) and arepartly replaced by hornblende. Accessory minerals include titanite, apatite, zircon and opaque minerals.Toronto stock, about 2 km northeast of Hediley township (Fig. 1.1), forms a subhorizontal body1.5 km long by 500 m wide that is elongate in a west-northwest direction. It is not known whether thestock is: (i) a composite body comprised of numerous dykes that fed the nearby sills, or (ii) one large bodywith numerous apophyses that formed sills in the adjacent sediments. The former interpretation ispreferred. Limited access to the area around the Toronto stock (because of active mining) preventeddetailed mapping, however Bostock (1929) traced several sills back to their source in the stock.The stock is a massive, medium grained, equigranular quartz diorite. It consists of hornblende,plagioclase (An40), orthoclase, quartz and rarely augite. Hornblende crystals are euhedral (<5 mm) andpoikilitic. Plagioclase crystals are subhedral to euhedral (<4 mm) and show reverse oscillatory zoning.Accessory and trace minerals include: biotite, zircon, apatite, titanite and opaques.A colour, compositional and textural zoning in the stock was recognized by Dolmage and Brown(1945). The lower exposed part of the stock consists of dark equigranular quartz diorite. An intermediatezone consists of augite diorite, and an upper zone is a pale homblende porphyritic gabbroic phase.However, the pale colour and porphyritic nature of the upper part of the stock is a result of groundmassreplacement by fine grained orthoclase, albite and quartz during skarn alteration (Plate 3.5). In addition,much of the pyroxene in the upper part of the stock appears to be secondary replacement of homblende.22Plate 3.5: Bleached hornblende phyric quartz dionte cut by fractures with calcite + garnet + pyroxeneenvelopes (unit 7: Toronto stock, Fig 1.1). Outcrop is along Princeton portal road, Nickel Platemountain.Plate 3.6: Nickel Plate sill complex (unit 7) intruding [imestones and siltstones of the Hedley formation(unit 2: Fig. 1.1). Note that the sills (brown) are thin where the limestones and siltstones (grey)are thinly bedded (middle-right of photograph) and thick where the limestones and siltstones arethickly bedded (middle of photograph). Photograph was taken looking north from Highway 3,one kilometre east of Hedley township.23Nickel Plate sill complex is exposed over a vertical distance of 1 000 m on the cliffs 1 km east ofHedley township (Fig. 1.1, Plate 3.6). At this locality, the sills vary from <ito 75 m in thickness, aretraceable along strike for over 2 km and comprise up to 40% of the stratigraphy. Because of its bandedappearance the mountain was called ‘kyish-ming’ (banded) by the natives and ‘Striped Mountain’ byDawson (1877). The striped appearance is caused by rusty weathering dark brown sills separated by greylimestones and siliciclastics. In thinly bedded mixed limestone and siltstone sections, the sills aregenerally numerous and thin (ito 5 m). In thicker limestone units they are less frequent and much thicker(>50 m). Individual sills vary from flat planar sheets to bodies that pinch, swell and bifurcate. They oftenthicken where they step across (probably up) stratigraphy. Sill contacts vary from straight to irregular(Plate 3.7), gradational and are brecciated rarely (Plate 3.8). Dolmage and Brown (1945) describe somegabbro contacts as gradational because it is locally difficult to define a precise contact between theintrusion and sediment. They attributed the gabbro composition and gradational contacts to assimilationof limey sediments by quartz diorite. Brecciated contacts are infrequent, but were observed by most of theearlier workers. Camsell (1910) describes short intervals along intrusion margins where the intrusion andsiliciclastics are mixed or gradational making it difficult to place a contact over a few metres. Similargradational contacts, described by Billingsley and Hume (1941), underlie the base of the ‘Upper Purple’ore in the Nickel Plate mine. They described quartz diorite porphyry underlying the southern part of theore zone that grades into a fine grained breccia in the central part. The breccia consists of fine grainedchert (siliciclastics) in a groundmass of fine grained secondary quartz that is intrusive in nature, sendingoff numerous apophyses across and along bedding. These gradational contacts, described by the aboveprevious workers, are interpreted to be related to synsedimentary sill intrusion (see peperitic marginsbelow). A brecciated contact observed along the Princeton portal road (this study) consists of rustyweathering quartz diorite clasts (< ito 50 cm) hosted in siltstones of the Hedley formation up to 2 m fromthe sill contact. This brecciated contact and those described by previous workers are interpreted as peperite(see Section 4.3.3). Cooling joints perpendicular to sill contacts locally are developed within the sills(Plate 3.9).24Plate 3.7: Hedley quartz diorite sill (unit 7) intruded into limestone of the Hedley formation (unit 2: Fig.1.1). Note irregular wavy contact of sill. Outcrop is along the Princeton portal road, Nickel Platemountain.Plate 3.8: Hedley quartz diorite sill (unit 7) in siltstones and limestone of the Hedley formation (unit 2:Fig. 1.1). Note the bleached white clasts of Hedley quartz dionte (globular peperite) within greylimestone near the sill contact. Outcrop is along the Princeton portal road, Nickel Platemountain.25Plate 3.9: Hedley quartz diorite sill (unit 7) in siltstone and limestone of the Hedley formation (unit 2,Fig. 1.1). Cooling joints perpendicular to sill contacts are prominent. Outcrop is along thePrinceton portal road, Nickel Plate mountain.Plate 3.10: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of hornblendeporphyritic Hedley diorite sill (unit 7: Fig. 1.1). Hornblende crystals are zoned.26The sills consist of hornblende (± augite) and plagioclase porphyritic quartz dionte. Thepoikilitic hornblende crystals are euhedral (<5 mm) and zoned (Plate 3.10). The plagioclase (An40)issubhedral to euhedral (<3 mm) and normally zoned. Rare augite crystals are <2 nun in diameter. Thegroundmass consists of a fine grained intergrowth of plagioclase with minor quartz, microcline andorthoclase. Accessory minerals include titanite, carbonate and opaques. Opaque minerals include pyrite,ilmenite, magnetite, pyrrhotite and arsenopyrite.Samples from the Hedley intrusions on a normative mineralogy diagram (Fig. 3.8: Streckeisenand Lemaitre, 1979) vary from quartz diorite to gabbro. They also plot mainly in the quartz diorite fieldon a TAS diagram (Fig. 3.9: Middlemost, 1985) and are generally subalkalic, although two samplesplotted in the aikaline field (Fig. 3.3). The subalkalic samples, all calcalkaline when plotted on a AFMdiagram, show a depletion in iron typical of calcailcaline differentiation (Fig. 3.4).Subvolcanic rocks are plotted on tectonic discrimination diagrams constructed for volcanic rocksin Figures 3.5 and 3.7. On Figure 3.5 (TiJlOO - Zr - Y*3) the data plots in both the island arc basalt andcalcalkaline basalt fields. These rocks are similar to those from modem day calcalkaline island arcs whenplotted on a spiderdiagram plot (Fig. 3.7; Sun, 1980).U-Pb analysis of zircon from the Hedley intrusive suite (Fig. 3.1: sample Hd-81 and Hd-273;Table B. 1) gave inconclusive ages due to lead loss and lead inheritance. One sample collected from theToronto stock contained insufficient zircon for analysis. Four fractions obtained from the Stemwinderstock (sample Hd-8 1) were inconclusive due to combined lead loss and inheritance of Paleozoic or olderzircon (Table B. 1, Fig. 3. lOa). If the intrusion is Triassic or younger, a three stage lead evolution isimplied by the old 207Pb/6 ages. The intrusion is most likely between 175 ± 0.6 Ma (youngest206Pb/38Uage) and 219 ± 11 Ma(207Pb/6 age of most concordant fraction). Sample Hd-273 fromthe relatively mafic quartz diorite phase of the Banbuiy stock gave a maximum age of 215.4 ± 4.0 Ma (J.Gabites, written conununication, 1993) based on five fractions. This age is given by the upper intercept ofan isochron (least squares regression) that passed through zero and the hvo non-magnetic fractions (‘aand ‘b’) that show the least inheritance (Table B. 1, Fig. 3. lOb). Two fine magnetic fractions (‘d’ and ‘e’)plot below concordia indicating inheritance of Cambrian or older zircon as well as lead loss. This suite27A\GRTLflanor thI-te/<northIte + orthoclase)Figure 3.8: Chemical composition of intrusive rocks from the Hedley area, south-central BritishColumbia plotted on normative diagram (Streckeisen and Lemaitre, 1979). Squares Hedleyintrusions; triangles = Mount Riordan stock; asterisks = Cahill Creek pluton.Figure 3.9: Total alkali vs. silica diagram (compositional fields defined by Middlemost, 1985) of intrusiverocks from the Hedley area, south-central British Columbia. Squares = Hedley intrusions;triangles = Mount Riordan stock; asterisks = Cahill Creek pluton.1-’£+LaNC0NL0•1ocJ+(‘-I42 SO 60SO2 (o-tZ7028to ,or. 1, Là tol,)0.0204, a is Oh o.n 0.021.,. •2S 0.20 0 22 C l•aO’pb/ a20 tolpb/ ?.20c. d.I? V20’Pb/ “u 20Pb/ Ue. P.005’I,,,,18711-9 52: : 0- - -101Pb7 t”u Pb! 9”UFigure 3.10: U-Pb concordia diagrams for analyses of zircons (J. Gabites, written communication, 1993),from intrusive and extrusive rocks in the Hedley area, south-central British Columbia. Samplesare located on Figure 3.1; zircon analyses are in Table B. 1. (a) Zircons are from quartz diorite,Stemwinder stock (unit 7, sample lId-Si). A minimum date of 175 ± 0.6 Ma is indicated. (b)Zircons are from quartz diorite, Banbury stock (unit 7, sample Hd-273). By extrapolation to zeroa 215±4 Ma age is indicated. (c) Zircons are from granodiorite, Mount Riordan stock (unit 9,sample Hd-406). An age of 194.6 ± 1.2 Ma with inheritance of 1719 ± 138 Ma is implied. (d)Zircons are from granodiorite, Cahill Creek pluton (unit 10, sample Hd-80). An age of 168.8 ±9.3 Ma is indicated. (e) Zircons are from quartz rhyolite porphyiy (unit 12, sample Hd-272). Adate of 154.5 + 8/43 Ma with inheritance of 391 + 2661-214 Ma is indicated. (f) Zircons arefrom quartz-feldspar dacite tuff, lower unit of Skwel Peken formation (unit 13a, sample Hd-271).An age of 187 ± 9 Ma is indicated.29does not cross-cut the Bromley batholith which has a minimum age of 193 ± 1 Ma (Table B.2). Previouslypublished K-Ar (amphibole) analyses from the Hedley intrusive suite (Toronto stock, 4 samples;Stemwinder stock, 1 sample) yielded dates that range from 175.0 ± 5.4 to 195.0 ± 6.0 Ma (Table B.2).3.5 Bromley batholith (unit 8)Bromley batholith (unit 8) forms a large body that intrudes the Nicola Group in the northwestcorner of the map area (Fig. 1.1). It consists of pale pink to grey, medium to coarse grained, equigranulargranodiorite. The crystal assemblage consists of hornblende, biotite, plagioclase (An30), orthoclase andquartz. Accessory minerals include sericite, apatite, epidote, carbonate and opaque minerals. The marginof the batholith, generally granodiorite, is locally diorite to quartz diorite in composition. Country rockssurrounding the batholith are biotite hornfelsed up to 1 000 m from the contact.Previously published dates (Table B.2) from the Bromley batholith are 173.4 ± 4.7 to 180.9 ± 5.4Ma (two K-Ar biotite analyses), 185.7 ± 2.8 to 188.1 ± 5.8 Ma (two K-Ar hornblende analyses) and 193.0± 1.0 Ma (U-Pb zircon analysis). The 20 Ma difference between the minimum K-Ar (biotite) and U-Pb(zircon) date likely represents partial resetting by the Cahill Creek pluton. Rocks of the Bromley batholithare similar in texture and composition to those of the Mt. Riordan stock. The later has an equivalent U-Pbzircon date of 194.6 ± 1.2 Ma.3.6 Mount Riordan stock (unit 9)Mount Riordan stock (unit 9) forms a small body in a area of poor exposure in the northeastcorner of the map area (Fig. 1.1). It is predominantly a medium to coarse grained, equigranulargranodiorite to tonalite that contains rare mafic xenoliths. The phenocrystic assemblage consists of:hornblende, biotite, plagioclase (An30), orthoclase and quartz. Accessory minerals include: carbonate,30sericite, epidote, chlorite, titanite, apatite, zircon and opaques. The stock is spatially related to tungsten-copper skarn mineralization and the Crystal Peak industrial garnet skarn at Mt. Riordan (Ray et at.,1992).Whole rock analysis of samples from the Mount Riordan stock plot in the tonalite field in Figures3.8 and 3.9. They are subalkalic (Fig. 3.3) and calcalkaline (Fig. 3.4).U-Pb anaylsis of zircon from the stock (Fig. 3.1: sample Hd-406) gave an age of 194.6 ± 1.2 Ma(3. Gabites, written communication, 1993). This age is defined by the lower intercept of an isochronpassing through an abraded magnetic and non-magnetic fraction (Table B. 1, Fig. 3. lOc). The fractionscontain inherited old zircon with an average age of 1719 ± 138 Ma.3.7 Cahill Creek pluton (unit 10)Cahill Creek pluton (unit 10) forms a large irregular body in the center of Figure 1.1. It has alaccolith like shape in cross-section and commonly occupies the contact between the Apex Mountaincomplex and the overlying Nicola Group. It is a massive, medium to coarse grained, equigranulargranodiorite to quartz monzodiorite that is characterized by about 5% mafic xenoliths up to 30 cm indiameter. Aplite forms irregular bodies along the upper contact of the pluton as well as small dykes inadjacent country rocks. The main body consists of: plagioclase (An20), orthoclase, quartz, hornblende andbiotite. Plagioclase crystals have both normal and reverse oscillatory zoning. Accessory and trace mineralsinclude: carbonate, sericite, chlorite, epidote, titanite, apatite, zircon and opaques. Locally, minormolybdenum-tungsten-quartz mineralization occurs as microveins and veins within aplite and adjacentcountry rocks.Samples plot in the quartz monzodiorite and granodiorite fields on the normative mineralogydiagram of Figure 3.8. They also plot in the quartz monzodiorite to granodiorite fields on the TASdiagram of Figure 3.9. The pluton is subalkalic (Fig. 3.3) and calcalkaline (Fig. 3.4).31U-Pb analysis of zircon from the pluton (Fig. 3.1, Table B. 1: sample Hd-80) gave an age of 168.8± 9.3 Ma (J. Gabites, written communication, 1993). This age is the upper intercept of an isochron (leastsquares regression) passing through zero and four fractions (Table B. 1, Fig. 3. lOd). Three of the fourfractions have lost lead, however the rock does not appear to contain inherited zircon. Previouslypublished K-Ar dates (Table B.2) for this body are 153.4 ± 4.6 to 161.3 ± 3.4 (eight K-Ar biotite analyses)and 159.9 ± 2.9 to 174.5 ± 5.2 (three K-Ar hornblende analyses).3.8 Lookout Ridge pluton (unit 11)Lookout Ridge pluton (unit 11) forms an elongate body in an area of poor exposure in thenorthern part of Figure 1.1. It is an isolated body related to the Osprey Lake batholith that occurs 10 km tothe north. The pluton consists mainly of massive, medium to coarse grained, orthoclase porphyritic quartzmonzonite. The phenocrystic assemblage consists of orthoclase (<30 mm), microcline, perthite, quartzand biotite. Accessory minerals include carbonate, sericite, chlorite, apatite, zircon and opaque minerals.The pluton is locally bordered by a thin unit of coarse grained hornblende-biotite diorite that mayrepresent a marginal phase.3.9 Rbyolite porphyry (unit 12)Rhyolite porphyry (unit 12) occurs as rare isolated dykes throughout the map area. The dykes aretypically less that 3 m thick. However, immediately west of Skwel Kwel Peken Hill, a 100-200 m thickbody occurs along the upper contact of the Cahill Creek pluton for 3.3 km (Fig. 1.1). It is pale pink to buffin outcrop, leucocratic, fine grained to aphanitic and is quartz-feldspar±biotite phyric. Quartz phenocrystsare anhedral to subhedral (<4 mm) and often have embayed rims (Plate 3.11). Plagioclase (An20)phenocrysts are subhedral to euhedral (<4 mm).3260Figure 3.11: K20vs. Si02 diagram (Gill, 1981) for the Skwel Peken formation, Hedley area, south-central British Columbia. Crosses (unit 13a) plot as dacite; diamonds (unit 13b) plot as medium-K andesite.Figure 3.12: Compositions of garnet expressed as the end members: AL (almandine) + PY (pyrope), SP(spessartine), and GR (grossularite) + AD (andradite) from a rhyolite dyke near Skwel PekenRidge, Hedley area, south-central British Columbia. Data is from Table D.1. Thesegarnets(circles: cores and rims) are compared to gannets from the Upper Cretaceous Capooserhyolite (boxes) and to garnet fields from a number of other geological settings (Andrew, 1988and references therein). Rims are relatively spessartine rich (Mn) compared to cores. P = plutonicfield; V = volcanic field; G greenschist field; A = amphibolite field.43532515.50Bo.soit_si_ )ccrt.H+ + +Lo —K50 65AL ÷ PYsP GR+AD33Rare flakes of biotite (<3 mm) are partially altered to chlorite. The groundmass consists of an intergrowthof quartz and feldspar. Accessoiy minerals include zircon and opaque minerals.U-Pb zircon analysis of zircon from the intrusion (Fig. 3.1, Table B. 1: sample Hd-272) gives adate of 154.5 + 8/-43 Ma (J. Gabites, written conununication, 1993). This age is the lower intercept of theisochron (least squares regression) passing through three fractions (Table B. 1, Fig. 3. lOe). The averageage of inherited zircon in fractions ‘a’, ‘c’ and ‘d’ is 391 + 266/-214 Ma. Fraction ‘b’ that plots well belowconcordia suggest it contains inherited zircon of a much older age than the other fractions.3.10 Skwel Peken formation (unit 13)Skwel Peken formation (unit 13) occurs in two separate outliers centered on Lookout Ridge andSkwel Kwel Peken Ridge (Fig. 1.1). It is a Middle Jurassic felsic to intermediate volcaniclastic unit thatoverlies the Whistle formation. Two distinct stratigraphic units, a lower and upper one, are recognized.The lower stratigraphic unit (unit 13 a), about 1 500 m thick, consists of massive, grey to maroon,feldspar-quartz phyric dacitic ash and lapilli tuff, and minor bedded tuffaceous siltstone, dust tuff andcrystal tuff. The ash tuff (Plate 3.12) contains a crystal assemblage of quartz (<2 mm), orthoclase (<3 mm)and plagioclase (<2 mm: ‘2o). The groundmass is a fine grained intergrowth of feldspar, quartz,devitrified glass, chlorite, epidote and opaque minerals. Contact with the underlying Nicola Group wasnot observed.The upper stratigraphic unit (unit 13b) occurs in the southern outlier, immediately west of SkwelKwel Peken Ridge. About 200 m thick and overlying the lower unit, it consists of massive dark greenplagioclase phyric andesite to basaltic crystal ash tuff and lapilli tuff. The plagioclase phenocrysts (<5mm: An20)exhibit normal and reverse oscillatory zoning (Plate 3.13). The matrix consists of a finegrained intergrowth of quartz, orthoclase, plagioclase, devitrified glass, chlorite and opaque minerals.34Plate 3.11: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of quartzporphyry (unit 12: Fig. 1.1). Embayed quartz phenocrysts occur in a fine grained quartzofeldspathic matrix.Plate 3.12: Photomicrograph (transmitted light, crossed polars, field of view 5.0 mm) of dacitic ashtuff from lower unit of the Skwel Peken formation (unit 13a: Fig. 1.1).35Whole rock analysis of samples from the felsic lower unit of this formation plot in the dacite fieldon the TAS diagram of Figure 3.2. The intermediate upper unit of this formation plots in the andesitefield on Figure 3.2. The formation is subalkalic (Fig. 3.3) and calcalkaline (Fig. 3.4).On a tectonic discrimination diagram constructed for intermediate rocks (Gill, 1981), both unitsof the Skwel Peken formation plot in the medium-K calcailcaline field (Fig. 3.11); the lower unit ismedium-K dacite and the upper unit is andesite. Incompatible element patterns of the Skwel Pekenformation (lower and upper unit) are similar to modem day calcalkaline island arcs (Figure 3.7).U-Pb analysis of zircon from the Skwel Peken formation-lower unit (Fig. 3.1, Table B. 1: sampleHd-271) gave a maximum date of 187 ± 9 Ma (J. Gabites, written communication, 1993). This estimate ofage is the upper intercept of an isochron passing through zero, the fine magnetic fraction, and the abradedcoarse non-magnetic fraction (Table B. 1, Fig. 3. lOf). The non-magnetic fraction ‘a’ contains inheritedzircon of Paleozoic or older age and has lost lead. The formation is probably the extrusive equivalent of asuite of Middle Jurassic intrusions that include the rhyolite porphyry, and the Cahill Creek and LookoutRidge plutons. Mineralogically and texturally these volcanic rocks resemble the rhyolite porphyry that is154.5 + 81-43 Ma (Table B.1, Fig. 3.lOe).3.11 Minor intrusionsMinor, narrow dykes less than 5 m thick are exposed throughout the map area (Fig. 1.1). Theircompositions range from basalt to rhyodacite.Several dark green andesite to basalt dykes in the vicinity of the Nickel Plate mine wereemplaced along north to northeast trending fractures. Characterized by chilled margins and carbonateamygdules, they probably represent feeder-dykes to the Tertiary Marron volcanics that locally crop out inthe area. Phenocrysts consist of sub-parallel twinned plagioclase (An40)and minor chioritized hornblendein a fine grained groundmass of feldspar and opaque minerals. Trace to accessory minerals includetitanite, rutile, epidote, ilmenite, apatite and clinozoisite.36Plate 3.13: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of andesitecrystal tuff from the upper unit of the Skwel Peken formation (unit 13b: Fig. 1.1).Plate 3.14: Photomicrograph (transmitted light, crossed polars, field of view 0.625 mm) of an igneousgarnet from a rhyolite intrusion near Skwel Kwell Peken Ridge.37A grey, fine grained to aphanitic, leucocratic rhyolite dyke that contains rare garnet crystals cropsout on Skwel Kwel Peken Ridge. This unit is spatially related to the Skwel Peken formation. The easterncontact of this body south of Skwel Kwel Peken Ridge is irregular and marked by weak flow banding thatdips moderately westward. The phenocryst assemblage of: orthoclase (<3 mm), biotite (<2 mm) andgarnet (<2 mm) is in a altered groundmass of fine grained: quartz, plagioclase (An10), orthoclase,muscovite, chlorite, epidote, zircon and opaque minerals. Altered orthoclase phenocrysts are oftensericitized. The pink, anhedral to euhedral, isotropic garnet crystals are commonly fractured and havecorroded margins (Plate 3.14). Microprobe analysis from core to rim across several crystals (Table D. 1,Fig. 3.12) indicate that some have almandine (iron and magnesium rich) cores and spessartine(manganese rich) rims, a zonation typical for igneous garnets (Green, 1977). Some crystals were unzonedalmandine. The chemistry of these garnets are compared to garnets from the Upper Cretaceous Capooserhyolite and garnets from a number of other geological settings (Andrew, 1988) in Figure 3.12. They fallwithin the plutonic field as defined by Andrew (1988) and references therein, but show a greater range inend member composition (about 45%) from core to rim as compared to garnets from the Capoose rhyolite(<5%). Progressive enrichment in manganese from core to rim may be a result of crystal fractionation,because apart from garnet, manganese is not a principal constituent of other igneous silicates (Miller andStoddard, 1981 in Andrew, 1988).3.12 StructureApex Mountain complex, not examined in detail during this study, exhibits several features notobserved in the overlying Nicola Group rocks. The greenschist metamorphic grade is higher than inNicola rocks (Monger, 1985). Polyphase deformation is indicated by tight to isoclinal folds with northeaststriking, steeply dipping axial planes and subhorizontal fold axes that are overprinted by broad open foldswith steeply dipping, northerly striking axial planes (Milford, 1984).38Nicola Group records Late Triassic extension and a Lower Jurassic to Cretaceous(?)compressional history. The overlying Skwel Peken formation was also affected by the Mesozoiccompression. Features related to Tertiary extension were not recognized in the Hedley area. Such featuresin the Okanagan area to the east are manifested as low angle detachment and high angle normal faultsthat preserve Tertiary volcanic and epiclastic rocks (Tempelman-Kluit and Parkinson, 1986).The Late Triassic extensional event produced northeasterly strildng normal faults and west-northwesterly striking fracture zones, The major normal faults from east to west are the Cahill Creek,Bradshaw and Chuchuwayha faults (Figs. 1.1 and 3.13). These are deep crustal faults that are rooted inthe Apex Mountain complex. They mark the eastern edge of a westerly sloping basin margin.Displacement on these faults during Late Triassic sedimentation, Carnian to Norian, formed a steppedseafloor of successively westward down dropped blocks. This is reflected in the deepening facies changesrepresented by the sequence of formations: Hedley to Chuchuwayha to Stemwinder. The vertical tosubvertical west-northwesterly striking faults controlled emplacement of some Hedley intrusions.Small upright ‘crumples’ with a wavelength of 30 m and amplitude of 3-5 m plunge 20-30° to thenorthwest (Dolmage and Brown, 1945). Hedley sills and adjacent sediment commonly are folded by these‘crumples’; rarely dykes at a low angle to bedding crosscut these folds (Billingsley and Hume, 1941). Suchstructures are economically important because many of the Nickel Plate orebodies form along their axes.The origin of these crumples is uncertain, however they may form by local compression associated withsill injection.Lower Jurassic to Cretaceous(?) compression produced a number of structures. Major onesinclude a district wide asymmetric anticline called the Hedley anticline (Billingsley and Hume, 1941),asymmetric minor folds, reverse faults and easterly directed thrust faults (Fig. 3.14).The axial plane of the Hedley anticline dips steeply west. Its trace lies along Cahill Creek east ofthe Nickel Plate mine (Fig. 1.1). Bedding dips are: moderately to steeply west in the western portion of themap area, subhorizontal in the central part of the map area around Nickel Plate mine, and vertical tosteeply overturned east of Cahill Creek. Poles to bedding in the Nicola Group (stereoplot: Fig. 3.15)indicate a subhorizontal fold axis with a moderate to steeply west dipping axial plane that strike 202°39(0)(b)(c)(ci)West EostR1 jet). P’l Copp.rfl.4d r1Stemwind.r F”9Chucbuwoiia F’1 H.dley f9Ap.x gountain222i foanation LJ breccia LLJ focmotion LJ fomotion L__J foanation .Z2J complexQ-JKlometresFigure 3.13: Schematic cross-sections of the eastern rifled margin of the Nicola basin during formation ofmajor units in the Hedley area, south-central British Columbia. (a) Extensional faults related torifling associated with the Late Tnassic Nicola arc. (b) Westerly directed paleocurrents produceda number of facies changes represented by the shallow water Hedley formation (siltstone andthick limestone), the intennediate Chuchuwayha formation (siltstone and thin limestone), and thedeeper water Stemwinder formation (argillite and rare thin limestone) during Late Triassic,Carnian to Norian, time. (c) Copperfield breccia (limestone breccia) formed a thin laterallyextensive unit that separated the overlying volcaniclastics from the underlying sedimentaiyfades. Seismic shock related to earthquakes associated with volcanism may have triggered thebreakup of reefal material to form this mass flow deposit. (d) Whistle formation (intermediatevolcaniclastics) mark the gradual change from westerly directed clastic sedimentation to airfalldeposits where facies changes are not recognized.-Sea eveI-1OO0m 79777 v997c’J977 ‘7 97 V 9 777 ‘7 77VV779VV7VVVV’7VV99VV7V99VV9777VVVVv v- v j49Vç,Vç,v VVVc7VVvvc’vc’’7 vvvc\ k’7799977vv9v7-\ VVVVVVVVVV ‘7VS’’7VV V\799’ ‘7V797V7V7799777‘V99VVV79’VVV79V777’799V97V79797V999VV 77999 ‘79VVVV vc’cc7’v79v7vV 9c’79 c’v7 ‘797972799 — VVVVV VVV2’7 999772729999’79ç’ç’99— Sea Level— Stemwlnder formation cuctuwa>ia formation Hedey frnotlon• 1 000m II ..._ej: ..97299cVV7VVV9V7VVV-- - - - VVV7VVVVVVVVVVVV799VVVVV29799 7999979929792’797’79 V7299V7’7VVVVVV‘7997 .7779 VV799VV7V9V2VVCopp.rfeld breccia-Sea Levelii!!—__—.=---_____:___J.vvvV99997vv977997 9799 9 V Vvvvv vvvv’7Vvvvv9vvv7799 VVV77VVVVVVVVV’:-: 79 9799 vvvvvV2vvvvvv9v92997— --— VVVVVVVVVV\ V9797 ‘7 97 972’9777797997 979VVVV9V9V9$VV’97 97977777 V 777‘79 99 9 9 77 7 777 VV79977- 9777779777’799v7VV 7 9 ‘7 ‘7 9 ‘7 7 9 7 7EV V V V 9 V 9VVV7VV 7 V V40Figure 3.14: Cross-section A-A’ through Stemwinder and Nickel Plate Mountain (see Fig. 1.1 for sectionlocation) showing Hedley anticine and reverse faults related to Lower Jurassic to Cretaceous (?)compression. Map units are: 1= Apex Mountain complex, 2= Hedley formation, 3 =Chuchuwayha formation, 4= Stemwinder formation, 5= Copperfield breccia, 6 Whistleformation, 7 = Hediley intrusions, 8 Bromley batholith, 10 Cahill Creek pluton. Line typesare: dots = stratigraphy, medium dash = geological contacts.41(0)(b)NFigure 3.15: Stereoplots of structural measurements from the Nicola Group, Hedley area, south-centralBritish Columbia. (a) Poles to bedding (1414 measurements). (b) Poles to axial planar cleavage(18 measurements). The average of these axial planar cleavage measurements strikes 2320 anddips 7g0 northwest.N42(average of 1414 measurements). Axial planar cleavage associated with this fold is poorly developed; itstrikes 232° and dips 78° west (average of 18 measurements). Asymmetric minor folds (Plate 3.15) arerare but widespread. Their orientations mimic the district wide Hedley anticline.Reverse faults mark compressional reactivation of many of the Late Triassic normal faults. Forexample, uplift on the west side of the Bradshaw fault may be up to 200 m based on the displacement ofthe contact of the Cahill Creek pluton and the Nicola Group (Fig. 3.14).Westerly dipping, easterly directed thrust faults have been identified underground at the NickelPlate and French mine, but are not observed on surface. Duplex like structures (Plate 3.16), observed oncliffs northwest of Hedley township, may be related to thrust faulting.3.13 Galena lead isotopesGalena lead isotope ratios from the Nickel Plate gold skarn and the Copper Mountain copper-gold porphyiy deposit are presented in Table B.3. The data (provided by C.I. Godwin, Department ofGeological Sciences, The University of British Columbia, written communication, 1994), are plotted onconventional lead-lead diagrams in Figure 3.16. These two deposits are compared because they both: (i)represent large deposits of gold, (ii) are of similar Jurassic age, (iii) were formed by intrusive activity, and(iv) were generated within Quesnellia.Generally, the galena lead isotope data for these two deposits are similar. The data plot betweenupper crustal lead characterized by the shale curve (Fig. 3.16, SH: Godwin and Sinclair, 1982) and mantlelead (MN: Zartman and Doe, 1981). This is characteristic of lead mixed between reservoirs in an orogeneor island arc setting. (Straight lines joining the present day ends of the mantle model and the shale curvemodels approximate the mixing trends involved in orogene lead.) The average composition of galena leadfrom Copper Mountain and Hedley is a good representation of Late Triassic to Lower Jurassic (ca. 208Ma) lead on an orogene like growth curve for Quesnellia.43Plate 3.15: Asymmetric minor fold within thinly bedded siltstones of the Hedley fonuation (unit 2: Fig.1.1). The axial plane strikes northeast and dips steeply west. Photograph was taken lookingnorth, approximately 1 km north of Hedley township along Bradshaw creek.Plate 3.16: Duplex like structures within Chuchuwayha formation (unit 3: Fig. 1.1) probably related toLower Jurassic thrust faults. Photograph was taken looking north from Highway 3 at Hedleytownship.4420.2020.460• 20.72S20.98S2 1.2421.5087 86 85 84 83 82 81 80.0 20’Pb/06P 100.015.4517.5 20.5Figure 3.16: Galena lead isotopes (Table B.3) from the Nickel Plate gold skarn and Copper Mountaincopper-gold porphyry deposit, south-central British Columbia. Generally, the isotope data plot asorogene lead characterized as a mixture between upper crustal lead represented by the shale curve(SH: Godwin and Sinclair, 1982) and mantle lead (MN: Zartman and Doe, 1981). Straight linesjoining the present day ends (n = now or 0 Ga) of the mantle models and the shale curve modelsapproximate the mixing involved in orogene or island arc lead. The probably lower crustalBluebell curve model (BB: Andrew et a!., 1984) does not appear to characterize the lead from thedeposits. n now, 0.0 Ga. p base of Permian, 0.29 Ga. c = base of Cambrian, 0.57 Ga. 4 204error is much less than 0.1% 2o error.403938153Copper Mountain SH *Hedley ******** P*n** CMNnxxX BB15.6515.5516.5 19.545Neither the shale curve model (SM) or mantle model (MN) are likely to relate very closely ordirectly to the plumbotectonic environment (Doe and Zartman, 1979) of Quesnellia. Consequently, the ageof the deposit can not be even approximately estimated from the framework models. In addition, theprobably lower crustal Bluebell curve model (BB: Andrew et al., 1984) does not appear to characterize thelead.The Copper Mountain lead is slightly more primitive that the Nickel Plate data; that is, it appearsto have a slightly greater mantle component. This suggests that the large alkalic porphyry system atCopper Mountain had relatively limited access to upper crustal components. On the other hand, thesediments involved in skam mineralization at Hedley might have contributed the slightly morepronounced upper crustal components.3.14 DiscussionThe Middle to Late Paleozoic Apex Mountain complex (unit 1) consists of mafic volcanic, chert,limestone and siliciclastic rocks, and forms the lowest stratigraphic unit in the Hedley area (Table 3.2).East of Winters Creek (Fig. 1.1), Milford (1984) interprets the complex to be an accretionary prismformed above an eastward dipping subduction zone. In this area, individual structural units in the ApexMountain complex young to the east. However, the overall package of rocks youngs westward (Milford,1984). Progressive eastwardly directed underthrusting and accretion ofyounger slices of ocean crust isresponsible for the northeastly striking shallowly dipping isoclinal folds (Milford, 1984). West of WintersCreek, the complex forms the eastern rifted basin margin on which sediments of the Nicola Group weredeposited.Late Triassic Nicola Group forms a north trending belt of rocks in southern British Columbiathat represents an island arc succession formed above an easterly dipping subduction zone (Monger, 1985;Mortimer, 1987). East of the main volcanic arc, a back-arc basin developed and is characterized by clasticsedimentary rocks, limestone and synsedimentary intrusions (Table 3.2: units 2 to 7). The Hedley areaTable3.2:Summaryofstratigraphy,chemistryandtectonicsettingoftheHedleyarea,south-central BritishColumbia.NamelUnit:Date1/AgeFieldRockChemicalRockMagmaDiscriminationRemarksFormationNameNameSeriesDiagramsSkwel Peken13bandesiteashtoandesite(Fig.subalkalic,continental arc?-subaerial depositionformation(upperlapillituff3.2)calcalkaline(Fig.3.7)unit)(Figs.3.3and3.4)Skwel Peken13a<187±9MaZdaciteashtolapillidacite(Fig.3.2)subalkalic,continental arc?-subaqueoustosubaerialformation(lowertuffcalcalkaline(Fig.3.7)depositionunit)(Figs.3.3-extrusiveequivalentofquartzand3.4)rhyoliteporphyry?Rhyolite12154.5+81-43MaZquaporphyry—----—-intrusiveequivalentofSkwelporphyryPekenformation?Lookout Ridge11164.5±4.8Mabquartzmonzonite------—-satelite bodytoOspreyLakeplutonbatholith10kmtothenorthCahillCreek10168.8.0±9.3MaZgranodiontegranodioritesubalkalic,continental arc?-laccolith-likebodyintrudednearpluton(Figs.3.8andcalcalkaline(Fig.3.7)ApexMountaincomplex-Nicola3.9)(Figs.3.3Groupunconformityand3.4)MountRiordan9194.6±1.2MaZgranodioritetonalite(Figs.3.8subalkalic,islandarc(Fig.-satelite bodytoBromleybatholithstockand3.9)calcalkaline3.7)(Figs.3.3and3.4)1.Z=u-Pbzirconanalysis,b=K-Arbiotiteanalysis,‘=fossil.C’Table3.2:Suinmaiyof stratigraphy,chemistryandtectonicsettingof theHedleyarea,south-central BritishColumbia(continued)...NamelUnit:Date1/AgeFieldRockChemicaiRockMagmaDiscriminationRemarksFormationNameNameSeriesDiagramsBromley8193±1 Magranodiorite——-—batholithHedleyintrusions7193±1to215.4±quartzdionte,quartzdioritesubalkalic,islandarc(Figs.-sill complexandstocks, minor4Ma1gabbro(Figs.3.8andcalcalkaline3.5and3.7)dykes;sillscontemporaneouswith3.9)(Figs.3.3sedimentationand3.4)Whistle—andesite tuffandandesite(Fig.alkalictoislandarc(Figs.source(NicolaGroup:easternformationsiltstone3.2)subalkalic3.5,3.6and3.7)volcanicfades)(Fig.3.3)Copperfield5LateCarnian-limestonebreccia———-seismicallytriggered(7)massbrecciaEarlyNorianflowderivedfromlimestonereefto(circa. 225Ma)theeast(Apex Mountaincomplex)Stemwinder4LateCarnian-argillitetsiltstone,———-depositedbywesterlydirectedformationLateNoriaJlimestonepaleocurrents (deeperwaterfacies)(circa. 220Ma)Chuchuwayha3Early-Middlesiltstone argi1lite,———-depositedbywesterlydirectedformationNoriant’(circa. 220limestonepaleocurrents (intermediate waterMa)facies)Table3.2:Sumniaiyofstratigraphy,chemistiyandtectonicsettingof theHedleyarea,south-central BritishColumbia(continued)....Name/Unit:Date1/AgeFieldReckChemicaiRockMagmaDiscriminationRemarksFonnationNameNameSeriesDiagramsHedleyformation2Early-Middlesiltstone ±———-depositedbywesterlydirectedNorian(circa. 22Olimestone,argillitepaleocurrents (shallowwaterMa)facies);hostseconomicgoldskarnsApexMountain1Ordovician,mafictuff,siltstone,———-ophiolitecomplex,accretionarycomplexDevonian,limestone,argillite,prismCarboniferous,chert,greenstoneMiddle-LateTriassiJ0049represents the eastern rifled margin of this basin. West of Hedley, much of this basin has been obscured byJurassic and Cretaceous intrusions (Table 3.2: units 8 to 13).The westward dipping basin margin apparently was controlled by normal faults such as theCahill Creek, Bradshaw and Chuchuwayha faults (Fig. 3.13). Displacement on these faults influencedsedimentation during Carnian to Norian times (Fig. 3.17). Westerly directed turbidity currents deposited:(i) siltstones and thick limestones as the shallower water Hedley formation (unit 2), (ii) siltstones and thinlimestones as the intermediate Chuchuwayha formation (unit 3), and (iii) argillite and rare limestones asthe deeper water Stemwinder formation (unit 4). Continued uplift and nondeposition or erosion issuggested by the thin, poorly preserved Hedley formation east of the Cahill Creek fault. The elasticsediments and limestone were probably derived from uplifted chert beds and limestone reefs in the ApexMountain complex along the basin margin to the east.Collapse of this Late Triassic basin is marked by deposition of the Copperfield breccia (unit 5)which separates the Hedley, Chuchuwayha and Stemwinder formations from the overlying volcaniclasticsof the Whistle formation. It occurs as a nearly continuous unit and appears to be a catastrophic massivegravity slide deposit derived from uplifted and faulted brittle reef material that has a provenance to theeast. Seismic shocks related to earthquakes associated with the start of volcanism may have contributed tothe generation of this unit. The relatively short lived basin (<20 Ma based on the range of conodont ages,Fig. 3.17) is similar to modern back-arc basins (Molnar and Atwater, 1978). Similar limestone brecciasare recorded in the Carboniferous to Permian Akiyoshi tenane of southwestern Japan (Kanmera and Sano,1991) and in Tertiary basins off the Nicaraguan Rise in the western Caribbean Sea (Hine et a!., 1992). Inthe Nicaraguan basin, one limestone breccia is approximately 120 m thick, extends 27 km along slope andapproximately 16 km out into the basin--similar to dimensions of the Copperfield breccia.The overlying Whistle formation (unit 6) tuffs are alkaline to subalkaline and have an island arctrace element signature similar to the eastern volcanic facies (Mortimer, 1987) of the Nicola Group. Thefinely laminated tuffaceous siltstone rapidly grades upwards into massive ash and lapilli tufl The tuffswere derived from airfall through water. Absence of major variations in facies and limestone units in the50dz4.e21DVest10 Torarcian. Pli.rbach1an st,incei tkn H,dIW nationEarlytorma200 Sinn,urian-,— HtongianNotionI P8 IP5 P4; Camlon I P14 PL (23C —Lodinion rio I P17P9 ru P7I4Iddl.AiihIafl240— —02.2o2 ..-Figure 3.17: Conodont ages from sedimentary formations in the Nicola Group, Hedley area, south-centralBritish Columbia. Data are from Table A. 1. Sample locations are shown on Figure 1.1. Note thatthe age range for the Hedley intrusions—based on a maximum age determined by U-Pb zircondating and a minimum age determined by contact relationships—is permissible with its intrusioninto unconsolidated Nicola Group sediments.a,0a,U04-.00a,0)0I.,a,01-0- W0-Id-0‘ HI120[3014015016017o1800 190210220230EarlyLateMiddleEarlyLabMiddle-5Q0DV4cTAiTtC-)p0 (00x0C30I3BIxIII”I.tIIIxIII,13p.1-S-5Figure 3.18: U-Pb and K-Ar dates for intrusive and extrusive rocks in the Hedley area, south-centralBritish Columbia Horizontal tick and vertical bar represents date and error of analysis,respectively. Data are from Table B. 1 and B.2. Locations are plotted on Figure 3.1.51Whistle formation tuffs suggests sea floor topography changed from a fault bounded basin to a relativelysmooth featureless surface after deposition of the Copperfield breccia.Late Triassic to possibly Early Jurassic calcalkaline quartz diorite to gabbro Hedley intrusions(unit 7) form porphyritic sills and dykes, and equigranular stocks. Many of the larger dykes and stocks(e.g. Stemwinder and Toronto stocks) were emplaced along east-west to northwest fractures that areperpendicular to northeast striking normal faults. These structures may reflect transform faults associatedwith Late Triassic rifling.Sills are best developed in the shallow water Hedley formation where they comprise up to 40% ofthe stratigraphic section, and are spatially and temporally associated with gold skarn mineralization onNickel Plate mountain. Sills are commonly <2 m thick in the thinly bedded siltstone and limestone.However, in the thick bedded limestone the sills are up to 75 m thick. Individual sill contacts vary fromplanar to highly irregular; they rarely are gradational or brecciated (peperite).The above morphological features and the indicated Late Triassic age of the sills, based onpreliminary U-Pb zircon dates (Fig. 3.18), suggest the sills were synsedimentary and emplaced intounconsolidated to poorly consolidated sediment. The apparent lithological control on sill thickness andfrequency in the Hedley formation may result from exclusion of sills from those limestone units thatdiagenetically lithilied quickly after deposition. Lithification of limestone on the seafloor is geologicallyinstantaneous, involving time spans on the order of 10 to 10 000 years (Choquette and James, 1987). Thesills, therefore, preferentially invaded the wet unconsolidated to poorly consolidated siltstone. Thepreponderance of sills over dykes is additional evidence that the sediments were not completely lithifiedduring sill intrusion (Lee, 1951). Lithified sediments fracture as a result of deformation associated withmagma emplacement; thus dykes are as likely to form as sills. Lack of sills in the Stemwinder formationmay be related to the increased lithostatic and hydrostatic pressure associated with the thicker sedimentarypile and deeper water environment (cf Kokelaar, 1982).The Early Jurassic Bromley batholith (unit 8) and Mount Riordan stock (unit 9) are calcalkalinegranodiorite to tonalite. They crop out along the northern boundary of the map area. The Mount Riordan52stock is spatially and temporally related to Cu-W mineralization and industrial garnet skarn on MountRiordan (Ray et al., 1992).The age and calcalkaline chemistry of the Bromley batholith and Mount Riordan stock in theHedley area may be explained by a change from moderate or steep to shallow east dipping subduction inthe Early Jurassic (Parrish and Monger, 1991). This would result in an eastward widening of the arc. TheEarly Jurassic calcailcaline low-K magmatism (i.e. Bromley batholith and Mount Riordan stock) in theHedley area and the high-K magmatism (i.e. Rossland volcanics) in southeastern British Columbia mayrepresent parallel belts equivalent to the magmatic belts documented by Mortimer (1987) in the LateTriassic Nicola Group farther west (Parrish and Monger, 1991). A similar interpretation of shallowingsubduction may be valid in explaining the juxtaposition of the slightly younger, probably Late Triassic,calcalkaline Hedley intrusions in a back-arc extensional setting.Middle to Late Jurassic calcalkaline magmatism is represented by the Cahill Creek pluton (unit10), Lookout Ridge pluton (unit 11), rhyolite porphyry (unit 12) and their extrusive equivalent--SkwelPeken formation (unit 13). The Cahill Creek pluton is quartz monzonite to granodiorite and has alaccolith like shape in cross-section. This shape suggests it rose diapirically to the unconformity betweenthe Apex Mountain complex and the Nicola Group. At this horizon it intruded laterally. Aplite phases atthe top of the stock and rhyolite porphyry dykes in the nearby country rocks formed as the main bodycrystallized. Minor W-Mo porphyry style mineralization is spatially and temporally associated with theaplite and overprints earlier gold skarn mineralization. Rhyolite porphyry dykes are texturally andmineralogically similar to the lower unit of the Skwel Peken formation. They presumably representsubvolcanic feeder dykes between the Skwel Peken volcanics and the deeper level Cahill Creek pluton.The consanguineous relationship among the granodiorite, aplite and rhyolite porphyry dykes was firstnoted by Camsell (1911).Skwel Peken formation consists of a lower unit of massive to bedded tuffaceous siltstone anddacitic tuff that is overlain by an upper unit of massive feldspar phyric andesite tufT. The formation wasdeposited in a nonmarine, shallow water to subaerial environment, which in part may explain its lack ofpreservation. It represents the first example of mid-Jurassic volcanism recognized in south-central BritishColumbia--although plutonism of this age is common and widespread in the Canadian Cordillera.Early to Middle Jurassic magmatism coincides with a change from extensional to compressionaltectonics as Quesnellia became accreted to North America. By about 185 Ma there was more than 200 kmof tectonic overlap such that, based on Nd-Sr isotopic data (Ghosh, 1990), the eastern margin of NorthAmerica reached at least to the Okanagan valley. Structures related to this compressional event includethe Hedley anticline and associated minor folds, reverse faults (reactivated normal faults) and thrustfaults.5354CHAPTER 4.0 GEOLOGY OF THE FRENCH MINE GOLD SKARN4.1 IntroductionThe abandoned French mine, 1 km southeast of the Nickel Plate mine, is the second largest goldproducer in the Hedley camp. It is located 240 km east of Vancouver and 40 km southeast of Princeton insouth-central British Columbia (inset, Fig. 1.1; NTS Maps 92HJ8E and 82E/5W; centered near 49° 19’30”N and 1200 01’ W).The original showing, discovered in 1905 by F.H. French, consisted of bornite + chalcopyritemineralization at the western extremity of a skarn zone in close proximity to a fault (French fault).Development work up to 1917 included an 11 metre adit and a 2.5 metre cross-cut and two lower adits,which failed to intersect mineralization. The property lay dormant until 1949 at which time it wasoptioned by the Kelowna Exploration Company who operated the nearby Nickel Plate mine illingsley eta!., 1949). Diamond drilling was completed in 1949 and underground development and production beganin 1950. Seasonal production totaled 27-36 tonnes per day and was hauled to the company mill in Hedley.Mining ceased in 1955 when the nearby Nickel Plate mine and mill shut down (Hedley, 1955; Lamb,1957); underground development up to this time included 310 m of drifting, 30 m of raising and 1 500 mof diamond drilling. Cariboo Gold Quartz Mining Company acquired the controlling interest in theproperty in 1956 and formed French Mines Ltd. to operate it. They completed underground developmentand mining up to 1961 and also constructed a 45 tonne/day ‘cyanide’ mill at Hedley. Development workduring this period included 910 m of drifting, 235 m of crosscutting, 275 m of raising and 4 400 m ofdiamond drilling. Grove Explorations Limited optioned the property in 1976 and completed geologicalmapping and rock sampling (Sharp, 1976; Westervelt, 1978a, 1978b; Stacey and Goldsmith, 1980),geophysical (electromagnetic and induced polarization) surveys (White, 1976) and diamond drilling(Stacey and Goldsmith, 1981). A potential reserve of 8 731 tonnes grading 5.1 g/t gold, 102.9 g/t silverand 2% copper that could be mined by open cuts and shallow underground workings was outlined (Sharp,1976). In 1983 some 1 497 tonnes of this ore was mined and milled at the Dankoe mill 64 km to the east(Godfrey, 1983). In 1988, Corona Corporation (formerly Mascot Gold Mines Ltd.) completed property55scale geological mapping, soil geochemistry and diamond drilling (Hammack, 1988; D. Bordin, personalcommunication, 1988, 1989). Production figures between 1950 and 1961, and in 1983 are incomplete,however British Columbia Geological Survey Branch M1NFILE data indicates 1 362 kg of gold, 180 kg ofsilver and 20 tonnes of copper were recovered from approximately 69 508 tonnes of ore (Table 1.1).Gold skarn mineralization at the French Mine is spatially and temporally related to aphyricbasalt sills (Hedley intrusions) hosted within shallow water siltstone and limestone of the Late TriassicHedley formation. The significant difference between the geology of the French mine and the nearbyNickel Plate mine is that gold skarn mineralization is associated with quartz diorite porphyry sills (Hedleyintrusions) at Nickel Plate mine. Morphological features of the phyric and aphyric sills, and preliminaryU-Pb zircon dates of the phyric intrusions support a model whereby the sills intruded Hedley formationsediments soon after deposition while poorly consolidated (Dawson et a!., 1990a and 1990b). Thisinterpretation has important implications with respect to the physical and chemical conditions during goldskarn formation. This chapter focuses on emplacement and chemistry of the sill complex, and zoning ofcaic-silicate alteration and associated gold mineralization about these sills. Data is from surface mapping,core logging, petrographic studies, and whole rock and electron microprobe analysis.4.2 Geology of the French- Good Hope mine areaThe French - Good Hope mine area occurs along the eastern rifled margin of the north trendingelongate Nicola back-arc basin (Monger 1985). This basin is underlain by oceanic rocks of the Middle toLate Paleozoic Apex Mountain complex on which sediments, sills and dykes of the Late Triassic NicolaGroup were deposited (Figs. 4.1 and 4.2). Post Nicola intrusive rocks occur as plutons and dykes. Latefaulting and folding is minor.56i Ic‘11--(—z________________________‘1 fI\ 6‘4, 6 ‘‘. ‘—G0OD HOPE10 / 6 - 1 0,5_ MINE—/ 10STD______ \ 1Cahill Creek luton 6 61 4Q2C£ 0 •, /4 —,6A&///1 / / //5)%// -10 6 I s12s10,f_/75- I, / 11//FRENCH MINE..> j4.( 1 e•-I4( — / /I——-—_ ‘ 10//10—_-Figi e 4.4/ 1 ° 1° Imeesc”s1‘c,.’10IIs1& 0 -/II10 I10// /I ,0 F 8/ 8 q1/ 0—Figure 4.1: Local Geology of the French- Good Hope mine area, south-central British Columbia. Mapunits are: 1 = Apex Mountain complex, 2 = Hedley formation, 5 Copperfield breccia, 6=Whistle formation, 7= Hedley intrusions, 10= Cahill Creek pluton. Line types are: thick dash =faults, medium dash = geological contacts, thin dash = gravel roads, thin continuous = rivers.Diamond drill holes, drilled in 1987-1989 by Corona Corporation are located and labeled. Cross-sections A-A’ and B-B’ are in Figure 4.2. French mine is detailed in Figure 4.4.57Section A — A’1600rn —:1z10I —i-__r—BOO—--—-— I C 3O 4QSection B — B’l600rn —1400m—l2OCn — -n-______g2___< 11QOQm______j_1 10aao ---— 1o — --—--------— IFigure 4.2: East - west cross sections A-A’ and B-B’ (see Fig. 4.1 for section locations) through theFrench - Good Hope mine area, south-central British Columbia. Map units are: 1= ApexMountain complex, 2= Hedley formation, 5= Copperfield breccia, 6 Whistle formation, 7=Hedley intrusions, 10= Cahill Creek phzton. Line types are: thick dash = faults, medium dash =geological contacts. Diamond drill holes drilled in 1987-1989 by Corona Corporation areidentified.584.2.1 Apex Mountain complex (unit 1)Apex Mountain complex (unit 1) consists of: (i) siliciclastic rocks, (ii) andesitic to basalticvolcanic rocks (greenstone), and minor (iii) chert pebble conglomerate, (iv) chert, (v) limestone, and (vi)ultramafic rock. The oceanic character is defined locally by the presence of mafic pillowed flows and chert(Milford, 1985). These units are detailed below and in Figures 4.1 and 4.2.Siliciclastic rocks crop out northwest of Winters Creek and southeast of the Cahill Creek plutonwhere they form a northeast striking, moderately dipping, west facing unit. Siltstone and argillite consistof mosaic quartz and minor plagioclase, apatite, white mica, clays, organic material and opaque minerals.Irregular veinlets (<1 mm) of mosaic quartz (<0.1 mm) may represent dewatering structures formedduring compaction and diagenesis of the sediment (Plate 4.1). These units were probably derived fromuplifted and eroded older portions of the Apex Mountain complex. They were deposited as turbidites alongthe west sloping basin margin.A metamorphic assemblage of biotite + cordierite + garnet overprints these rocks between thelower contact of the Cahill Creek pluton and Winters Creek. Biotite (<0.03 mm) forms pervasiverandomly oriented reddish brown flakes that are best developed in fine grained argillaceous layers (Plate4.2). Cordierite (<0.5 mm) occurs as weakly aligned anhedral to subhedral grains that contain numerousinclusions of biotite, quartz and rarely garnet (Plate 4.3). Garnet (<0.3 mm) forms rare anhedral tosubhedral pale pink grains surrounded by biotite and quartz (Plate 4.4). The distribution of metamorphiccordierite + garnet in siliciclastic units below the Cahill Creek pluton indicates that these rocks underwenthigher grade metamorphism associated with a deeper structural level than rocks overlying the pluton.Andesitic to basaltic volcanic rocks (greenstone) are associated with minor siltstone, limestone,chert and ultramafic rock, and form a heterogeneous sequence that underlies the French - Good Hopemine area. Road exposures west of the French mine consist of massive to wealdy layered brown biotiticvolcanic rock that contain phenocrysts of hornblende, and rarely, plagioclase. These units, interpreted tobe mainly tuffs with lesser flows or shallow sills, are occasionally separated by interfiow lenses oflimestone or siltstone. Some units are similar to aphyric basalt sills (Hedley intrusions) hosted within59Plate 4.1: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of siltstone fromthe Apex Mountain complex cut by irregular veinlets of mosaic quartz (unit 1: Fig. 4.1). Veinletsmay represent dewatering structures formed during sediment compaction and cliagenesis.Plate 4.2: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of biotite +cordierite altered argillite and siltstone from the Apex Mountain complex (unit 1: Fig. 4.1).60Plate 4.3: Photomicrograph (transmitted light, crossed polars, field of view 1.25 mm) of cordeiriteporphyroblasts in siltstones of the Apex Mountain complex (unit 1: Fig. 4.1). Cordierite isanhedral to subhedral and contains numerous inclusions of biotite, quartz and rarely garnet; somegrains exhibit sector twinning.Plate 4.4: Photomicrograph (transmitted light, crossed polars, field of view = 1.25 mm, field of view =5.0 mm) of clear to pink subhedral garnet crystals in siltstone from the Apex Mountain complex(unit 1: Fig. 4.1). Garnet is surrounded by biotite and quartz.61Hedley formation at the French mine, however their distribution in the Apex Mountain complex is poorlyunderstood because of poor exposure and pervasive biotite alteration associated with contactmetamorphism by the Cahill Creek pluton. Poorly bedded units that contain volcanic clasts may behyaloclastites derived from the associated volcanic units. From thin section, the volcanic rocks consist ofhornblende and minor plagioclase phenocrysts in a fine grained plagioclase - glass matrix. Hornblende(<10 mm) is euhedral and partially to completely replaced by brown biotite and ilmenite (Plate 4.5).Plagioclase (<2 mm: An40) is subhedral and partly altered to fine grained clay minerals. The matrixconsists of acicular feldspar microlites and glass overprinted by fine grained biotite and white mica.Accessory minerals include clinopyroxene, ilmenite and opaque minerals.Chert pebble conglomerate forms rare, resistant, discontinuous beds throughout the section. Thebeds are generally <3 m thick and can be followed along strike for up to 50 m. Clasts (<1 cm) of finegrained mosaic quartz are subangular and matrix supported (Plate 4.6). The matrix consists ofmicrociystalline quartz and feldspar that is overprinted by brown biotite, acicular actinolite-tremolite,white mica (muscovite), chlorite and opaque minerals. These deposits may represent coarse grained debrisflows that filled channels that mark pathways where sediments were discharged from an uplifted anderoded Apex Mountain complex. The sediments were discharged toward the west into the deeper basin.Chert occurs as rare, thin discontinuous grey to white beds within laminated siltstones. Beds are<2 m thick and traceable along strike for up to 10 m. They consist of microcrystalline quartz, rarefeldspar, and opaque minerals, and are overprinted by fine grained brown biotite. Locally, sphericalmosaic quartz clasts (<3 mm) are preserved in fine grained laminae. These laminae show the leastevidence of recrystallization and the contained round clasts likely represent radiolarian tests (Plate 4.7).The chert represents rare periods of quiescence when chemical precipitation occurred without beingdiluted by siliciclastics.Limestone recrystallized to marble occurs as rare disrupted blocks and thin beds within andesiticto basaltic rocks immediately west of the French mine. The disrupted blocks (<5 m) are interpreted to be62Plate 4.5: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of hornblendephyric andesite to basaltic volcanic rock from the Apex Mountain complex (unit 1: Fig. 4.1).Homblende phenociysts are partly altered to brown biotite and ilmenite.Plate 4.6: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of chert pebbleconglomerate from the Apex Mountain complex (unit 1: Fig. 4.1). Reciystallized chert clast is ina fine grained matrix of quartz, feldspar, biotite, tremolite-actinolite, muscovite, chlorite andopaque minerals.- -,63Plate 4.7: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of chert from theApex Mountain complex (unit 1: Fig. 4.1). Spherical microcrystalline quartz grain (<3 mm) mayrepresent radliolarian tests.Plate 4.8: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of serpentirnzedultramafic (dunite) from the Apex Mountain complex (unit 1: Fig. 4.1). Sheared and fracturedolivine is altered to chrysotile and magnetite.64olistoliths derived from carbonate reefs somewhere to the east. Bedding in the tuffs underlying the blocksis locally disrupted. Thin discontinuous limestone beds separate some of the volcanic horizons. Such bedsare <3 m thick, traceable for up to 50 m, and often contain graded chert clasts and broken shell fragments.Ultramafic rock was intersected from 49.4 to 55.4 m in drill hole GN89-62 collared 200 mnortheast of the French mine (Fig. 4.1). It occurs as fine grained to aphanitic black and white boudinagedbands <5 mm thick in hand sample. From thin section, the rock, originally probably dunite, consistsmainly of sheared and fractured olivine altered to chrysotile and magnetite (Plate 4.8). This rock-type wasnot identified during surfiice mapping, and therefore, the extent of this minor unit is unknown.4.2.2 Nicola Group (units 2-6)Nicola Group (units 2-6: Section 3.3) forms a westerly, shallow dipping unit that unconformablyoverlies the Apex Mountain complex (Figs. 4.1 and 4.2). In the French- Good Hope mine area, it consistsof the Hedley formation (unit 2), Copperfield breccia (unit 5) and Whistle formation (unit 6). These unitsare detailed below.Hedleyformation (unit 2) forms a thin discontinuous unit <50 m thick of interbedded siltstone,limestone and minor argillite. Siltstones are white and consist of recrystallized microcyrstalline quartz.Limestone forms massive to weakly bedded units that are recrystallized to marble. The unit is preserved inpaleotopographic lows around the French and Good Hope mine along the westerly sloping basin edge.West of the Cahill Creek fault this unit dramatically thickens to over 500 m where it hosts gold skarnmineralization at the Nickel Plate deposit.Copperfield breccia (unit 5) overlies the Hedley formation and Apex Mountain complex. It variesfrom <10 m to 100 m in thickness. The unit consists of massive to bedded limestone breccia andconglomerate with minor interbeds of thinly laminated limestone. Limestone makes up 95% of the clasts;they are <5 to 50 cm in diameter, subangular to subrounded, and both clast and matrix supported. Rareclasts of tuft argillite and aphyric basalt occur within this unit. In the vicinity of the Good Hope - French65mine area, the limey tuffaceous matrix is altered to brown garnet ± clinopyroxene reaction (orbimetasomatic diffusion) skarn (Rose and Burt, 1979); the limestone clasts and beds are altered to whitemarble and wollastonite (Plate 4.9). This reaction skarn, is likely caused by the Cahill Creek pluton,which underlies much of the French - Good Hope mine area. It was previously called the Pinto formationand was thought to be a tectonic breccia related to thrust faulting (Hedley, 1955). A similar tectonicorigin, related to the Bradshaw thrust fault (Billingsley and Hume, 1941) was given for the limestonebreccia (Copperfield breccia) overlying the Nickel Plate deposit. However, mapping by Ray eta!. (1986)interpret this unit to be a massive gravity slide deposit formed by breakup of reefal material with aprovenance to the east. It marks the change from westerly directed clastic sedimentation (units 2-4) tovolcaniclastic and pyroclastic rocks of the Whistle formation (unit 6). Seismic activity (i.e. earthquakes)related to the onset of volcanism may have been responsible for basin collapse and deposition of this unit.Whistleformation (unit 6) conformably overlays the Copperfield breccia. The unit has amaximum thickness of about 200 m in the French - Good Hope mine area. It consists of thin beddedtuffaceous siltstone that grades upward into massive andesitic to basaltic ash and lapilli tufl The lowerpart of the unit is markedly epiclastic and exhibits features that indicate the unit is right-way-up (e.g.graded beds, flame textures and load casts). Paleocurrent directions are predominantly from the east.Biotite + potassium feldspar + clinopyroxene hornfels is common in the lower sedimentary section of thisunit where it is in close proximity to the Cahill Creek pluton.4.2.3 Intrusive units (units 7-12)Hedley intrusions (unit 7), Cahill Creek pluton (unit 10), and rhyolite porphyry (unit 12) occur inthe French - Good Hope area. These units are described below and in Figures 4.1 and 4.2. Units 8, 9 and11 were not noted in the French - Good Hope area, but occur regionally (see Sections 3.5, 3.6 and 3.8,respectively).66Plate 4.9: Photograph of Copperfield breccia at the French mine (unit 5: Fig. 4.1). The limey tuffaceousmatrix is altered to garnet and the limestone clasts are altered to marble and/or wollastonite. Thisskarn apparently is a metamorphic reaction skarn formed by the intrusion of the adjacent CahillCreek pluton (unit 10).Plate 4.10: Photomicrograph (transmitted light, crossed polars) of hornblende granodiorite from theCahill Creek pluton (unit 10: Fig. 4.1). Homblende crystals are altered to brown biotite, chlorite,carbonate and sphene.67Hedley intrusions (unit 7) form phyric and aphyric dykes, sills and stock like bodies that arespatially and temporally associated with gold skarn mineralization in the French- Good Hope mine area(Fig. 4.1). The phyric intrusions valy from equigranular quartz diorite to hornblende porphyries. Aphyricintrusions form thin sills, dykes or margins to hornblende phyric intrusions. Both the hornblende phyricand aphyric intrusions are similar to units in the Apex Mountain complex described in Section 4.1.Cahill Creek pluton (unit 10) forms a large body that occupies the western portion of the maparea. Flat lying to shallow dipping tongues from this body intrude along or close to the contact betweenthe Apex Mountain complex and the overlying Nicola Group in the eastern part of the map area (Figs. 4.1and 4.2). Siliciclastics of the Apex Mountain complex below and to the east of the intrusion are biotite +cordierite + garnet hornfelsed. Tuffaceous siltstones (Whistle formation) and limestone breccia(Copperfield breccia) of the Nicola Group, above and to the west of the intrusion, are altered to cabsilicate reaction skarn. The pluton is medium grained, equigranular, biotite-hornblende granodiorite tomonzodiorite. It consists of: plagioclase (An20), orthoclase, quartz, biotite and hornblende. Accessoiyminerals include apatite, zircon and opaque minerals. Plagioclase crystals exhibit normal and reversezoning, their cores are preferentially altered to sericite. Hornblende crystals are pseudomorphed by brownbiotite, which is altered to chlorite + carbonate + titanite (Plate 4.10).Aplite occurs as discrete lenses along the upper contact of the pluton, and as isolated dykes in thesurrounding country rocks. It consists of fine grained quartz, plagioclase (An10)and orthoclase.Accessory minerals include: muscovite, chlorite, apatite, titanite, zircon and opaque minerals. W-Momineralization is spatially and temporally related to this intrusion. It occurs as disseminations and veins ofquartz ± actinolite, epidote, molybdenite and scheelite in the aplite and adjacent country rocks (Plate4.11). At the French and Good Hope mines, the close proximity to the upper contact of the Cahill Creekpluton has caused the earlier gold skarn to be overprinted by this mineralization. Rock chip samples froma drift and incline above the Granby adit near the French fault returned 36 m grading 0.68% W03 and 15m grading 0.58% W03, respectively (Westervelt, 1978a).Rhyolite porphyry (unit 12) occurs as isolated thin dykes (<3 m thick) throughout the map area.They are white to beige, massive and have phenocrysts of quartz, plagioclase and orthoclase (Plate 4.12).68Plate 4.11: Quartz + actinolite + epidote ± molybdetute ± scheelite veins related to the aplite phase of theCahill Creek pluton (unit 10: Fig. 4.1). Veins cross-cut garnet skarn related to intrusion of theolder Hedley intrusions (unit 7); the protolith to the garnet skarn is Hedley formation limestones(unit 2). Photograph is from the southern end of the Good Hope open pit.Plate 4.12: Rhyolite porphyiy (unit 12: Fig. 4.4) containing phenoczysts of quartz, plagioclase andorthoclase in an aphanitic groundmass. Photograph is along the upper haulage track west of the3920 Level adit.69Quartz phenocrysts (<3 mm) are anhedral to subhedral and occasionally have resorbed rims. Plagioclase(<2 mm: An10)and orthoclase (<2 nun) phenocrysts are subhedral and partially altered to clay andcarbonate. Groundmass consists mainly of fine grained myrmekite (Plate 4.13). Accessory mineralsinclude: biotite, titanite, zircon, carbonate, clays, chlorite and opaques. These dykes are interpreted to befeeders between the Cahill Creek pluton and the overlying Skwel Peken formation volcanics that crop outon Lookout Mountain 7 km north of the French mine.4.2.4 StructureStructural elements identified (Figs. 4.1 and 4.2) include: (i) northeast striking steeply dippingfaults, (ii) northeast striking moderately west dipping faults, and (iii) minor open folds. These are detailedbelow.Northeast striking steeply dippingfaults include the Cahill Creek, Good Hope, French and Gulchfaults. The Cahill Creek fault is a northeast striking, steeply dipping normal fault related to Late Triassicextensional tectonics. This fault influenced sedimentation during Carnian to Norian time. Hedleyformation, less than 50 metres thick east of this fault, dramatically thickens to over 500 metres west of thefault. Other northeast striking faults such as the Good Hope, French and Gulch faults are poorly defined.The Good Hope fault forms a strong linear depression that strikes northeast to east and separates the GoodHope mine area in the north from the French Mine area to the south. The fault was not observed inoutcrop, however a topographic trace of the fault indicates it is steeply dipping to the south. Movement onthe fault appears to be right lateral, mainly strike-slip, and in the order of 1 000 m based on thedisplacement of a Cahill Creek granodiorite dyke that outcrops west of the French and Good Hope mines(Figs. 4.1 and 4.2). The French fault is mapped in roadcuts at the French mine where it strikes 055° anddips 75° southeast; in a small crosscut north of the Granby adit it strikes 055° and dips 60° southeast. Thefault has approximately 1 m of clay gouge and separates aphyric Hedley intrusion (unit 7) from skarnaltered limestones and siltstones (unit 2); displacement across the fault is uncertain, but appears to be70Plate 4.13: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of quartz rhyoliteporphyry (unit 12: Fig. 4.4).Plate 4.14: Quartz diorite of the Hedley intrusions contains numerous mafic xenoliths and forms a stocklike body at the French mine (unit 7: Fig. 4.4). Photograph is of outcrop along road 50 mnorthwest of the Cariboo adit, French mine.71minor. The Gulch fault was not observed in outcrop, however, it forms a linear depression on surface thattrends north-northeast. Underground the fault was mapped in the Cariboo adit and the lower stope whereit strikes 0280 and dips 800 east (Fig. 4.4). It forms a two metre thick sheared and brecciated zone with upto 1.0 m of clay gouge. A 1 m thick intermediate to mafic dyke infills the fault and has beenhydrothermally altered to clay. Displacement across the fault is uncertain.Northeast striking moderately west dipping faults are represented by the Cariboo fault (2000/400west). It was intersected in a small drift east of the Cariboo adit (Fig. 4.4), but was neither identified onsurface nor were linears identified on aerial photographs where the fault would project to surface.Underground the fault has slickensides that indicate mainly dip slip movement. It separates skarn alteredHedley formation sediments from the underlying Apex Mountain complex. An underground drill program(1 000 m in 7 drill holes) to test the panel below the Cariboo thrust failed to intersect skarn altered Hedleyformation sediments (Stacey and Goldsmith, 1981). All holes encountered chlorite + serpentinite alteredmafic volcanics and sediments, and minor limestone--presumably of the Apex Mountain complex. Mostholes terminated in the Cahill Creek granodiorite.Minor open folds occur throughout the Nicola Group in the French- Good Hope mine area (Figs.4.1 and 4.2). Overall the Nicola Group forms a northeast striking and shallowly westward dipping unitthat unconformably overlies more structurally deformed Apex Mountain complex. This generalrelationship of shallowly dipping units above the Cahill Creek pluton and steeply dipping units below thepluton was noted by Hedley (1955). Stereoplot of poles to bedding (Fig. 4.3a) in the Nicola Group indicatethat the unit strikes 226° and dips 18° northwest (average of 68 measurements). Locally, in the Frenchmine area (Fig. 4.4), Nicola Group bedding strikes east-northeast and dips shallowly about 30° to thenorthwest. Fold axes are subhorizontal and strike northeast. Stereoplots of poles to bedding (Fig. 4.3b) inthe Apex Mountain complex indicate that the unit strikes northeast and dips moderately to steeply eastand west. The best fit girdle of the poles to bedding strikes 313° and dips 82° northeast suggestingshallow northeast plunging folds. Thus folding in the Apex Mountain complex and the Nicola Group aresimilar in strike of axial planes. However, folding in the Nicola Group is more open.72(a)(b)NNFigure 4.3: Stereoplots of structural measurements from the French- Good Hope mine area, south-centralBritish Columbia: (a) poles to bedding (68 measurements) from the Nicola Group; (b) poles tobedding (27 measurements) from the Apex Mountain complex.734.3 Phyric and aphyric Hedley intrusions (unit 7)4.3.1 Detailed descriptionHedley intrusions (unit 7) form sills, dykes and irregular stock like bodies in the French - GoodHope mine area (Fig. 4.1). They vary from: (i) fine to medium grained quartz diorite to (ii) hornblendephyric tachylitic basalt to (iii) aphyric tachylitic basalt. The hornblende phyric and aphyric intrusions areunique to the French Mine area, whereas quartz diorite occurs throughout the district.Fine to medium grained quartz diorite forms a large sill (<50 m thick) that intrudes along ornear the contact of the Copperfield breccia and Whistle formation northeast of the French mine. At theFrench mine, it forms a stock like body containing numerous mafic xenoliths (Plate 4.14), and a numberof smaller dykes and sills (Figs. 4.4 and 4.5). It consists of hornblende (<3 mm) and plagioclase (<2 mm:An40)phenocrysts in a fine grained matrix of plagioclase, orthoclase and quartz. Accessory mineralsinclude biotite, zircon, apatite, titanite and opaque minerals. A sample collected from the quartz dioritestock like body for U-Pb zircon dating contained insufficient zircon for analysis.Hornblende phyric tachylitic basalt occurs as sills and dykes within the Hedley formation at theFrench mine (Figs. 4.4 and 4.5). Euhedral hornblende (<1 cm) and rare plagioclase crystals (<3 mm)occur in a fine grained matrix of feldspar microlites, glass and opaque minerals (Plate 4.15). Thehornblende phenocrysts are partly to completely pseudomorphed by fine grained brown biotite.Aphyric tachylitic basalt occurs as thin brown sills, dykes or as margins to phyric sills (Plate4.16) and stock like bodies within the Hedley formation at the French mine. Stock like bodies exposed inunderground stopes may be composite bodies consisting of numerous dykes that fed the adjacent sills (Fig.4. 16a). Thin beds of structureless Hedley formation siltstone and limestone separate the sills; these bedsvary from <0.5 to 3 m thick (Plate 4.17). The sills are <2 cm to a few metres in thickness. Irregular upperand lower contacts with pronounced lobes, fingers and stringers commonly thicken, thin, twist and turnover distances of <1 m. Along one sill contact, spherical clasts of basalt are surrounded by Hedleyformation sediment (Plate 4.18). These admixtures of igneous clasts enclosed within sediment and up to20 cm from the sill contact are interpreted to be globular peperite (see Section 4.3.3).74Figure 4.4: Detailed geology of the French Mine, south-central British Columbia. Map units are: 1 =Apex Mountain complex, 2= Hedley formation, 5= Copperfield breccia, 6= Whistle formation,7’ Hedley intrusions, 10= Cahill Creek pluton. Rock abbreviations are: M = marble, Mbx =marble breccia, Sist = siltstone, Bat = mafic ash tuff, Cht = chert, Bin = aphyric mafic intrusion,hBin = hornblende phyric mafic intrusion, Aat = intermediated ash tuft; Ga = garnetite skarn, Di= diorite, Gd = granodiorite. Line types are: thick dash = faults, medium dash geologicalcontacts, thin dash = gravel roads, dash-dot underground workings. The collar of diamond drillhole GN89-63 is marked. Contours are in feet above sea level.75Figure 4.5: North- south cross-section A-A’ (see Fig. 4.3 for section location) through the French mine,south-central British Columbia. Map units are: 1= Apex Mountain comple; 2= Hedleyformation, 5 = Copperfield breccia, 6= Whistle formation, fl Hedley intrusions, 10 = CahillCreek pluton. Rock abbreviations are: M = marble, Mbx = marble breccia, Sist = siltstone, Bat =mafic ash tuft; Cht = chert, Bin = aphyric mafic intrusion, hBin = hornblende phyric maficintrusion, Mt = intermediated ash tiM, Ga = garnetite skarn, Di = diorite, Gd = granodiorite.Line types are: thick dash = faults, medium dash = geological contacts, dash-dot = undergroundworkings.76Plate 4.15: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of hornblendephyric Hedley intrusion (unit 7: Fig. 4.4). Euhedral hornblende ciystals are partly replaced byfine grained biotite.Plate 4.16: Photograph across aphyric- hornblende phyric contact (dashed lines), Hedley intrusion (unit7: Fig. 4.4). Contact is gradational over 10’s of centimetres. Outcrop is along upper haulage trackimmediately east of the “open” stopes.77Plate 4.17: Aphyric Hedley sills (unit 7: Fig. 4.4) enveloped by a 1cm rim of structureless Hedleyformation siltstone (unit 2). Note the irregular wavy sill contact. Outcrop is along upper haulagetrack innnediately west of the 3920 Level adit.Plate 4.18: Possible globular peperite along contact of Hedley formation siltstone (unit 2: Fig. 4.4) andaphyric Hedley sill (unit 7). Exposure is on the back of the Granby adit, approximately 75 metresfrom the portal.78Aphyric intrusions vaiy in texture from altered glass to randomly oriented microlites ofplagioclase and ilmenite in an altered glass matrix. The glass can be flow banded and folded (Plate 4.19),or massive with well developed perlitic cracks (Plate 4.20). Plagioclase (<1 mm) forms radiating splays ofacicular crystals that have a common nucleation point (bow-tie texture [Lofgren, 1974]: Plate 4.21). Thesecrystals in cross-section (belt-buckle texture [Bryan]: Plate 4.22) have cores of altered glass. Ilmeniteoccurs as acicular crystals (<1 mm) and as a fine grained dusting throughout the matrix. In some thinsections, vesicles and irregular microveinlets of mosaic quartz cut the altered glass matrix (Plate 4.23).These irregular structures, interpreted as sedimentary dykelets, formed as a result of siltstone or silica richfluids infilling fractures created by quenching of the basalt during intrusion.4.3.2 PetrochemistrySixteen samples of Hedley intrusion were analyzed and are used to: (i) compare the compositionof the phyric and aphyric bodies, (ii) chemically classify the rocks, and (iii) compare their compositionswith those of known tectonic settings. Most of the phyric intrusions are overprinted by biotite; glass in theaphyric intrusions has been replaced by biotite, chlorite, actinolite-tremolite, clays and unknown finegrained minerals. Alteration likely affected the major element chemistry; therefore classification schemesusing these elements may be suspect. Immobile trace elements, relatively unaffected by hydrothermal andlow grade metamorphic processes, are used in some of the diagrams below. Tables C.3 and C.4 presentsmajor element chemistry along with their calculated Cross, Iddings, Pearson and Washington (CIPW)normative mineralogy, and trace element chemistry, respectively. Sample locations are plotted on Figure4.6.Quartz diorite (field name, unit 7, Fig. 4.1 and Map 1) plots in the quartz diorite field on anormative mineralogy diagram (Fig. 4.7: Streckeisen and Lemaitre, 1979). On a total alkali vs. silica(TAS) diagram (Fig. 4.8: Middlemost, 1985) it plots in the monzodiorite, quartz monzodiorite and quartzdiorite fields. These samples have higher Na20values (average of fourteen analyses 4.5%) compared to79Plate 4.19: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of flow bandedaphyric Hedley sill (unit 7: Fig. 4.4). Sample is from lower stope of the French mine.h-a( 1’q -,-‘. ft f J. ‘-‘ i’-:; dpj -f:c:;-. ‘q.aPlate 4.20: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of quenched,glassy, aphyric Hedley sill (unit 7: Fig 4.4) with well developed perlitic cracks. Sample is fromlower stope, French mine.80Plate 4.21: Photomicrograph (transmitted light, crossed polars, field of view 5.0 mm) of quenchedaphyric Hedley sill (unit 7: Fig. 4.4). These radiating splays of acicular plagioclase crystals witha common nucleation point are called “bow-tie” texture (Lofgren, 1974). Sample is from lowerstope, French mine.Plate 4.22: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of aphyricHedley sill (unit 7: Fig. 4.4). Plagioclase crystals have altered glass cores. Such textures aredescribed as “belt-buckle” texture (Bryan, 1972). Sample is from lower stope, French mine.Plate 4.23: Photonucrograph (transmitted light, crossed poiars, field of view = 1.25 mm) of mosaicquartz vesicles and microveinlets (on right) in aphyric Hedley sill (on left: unit 7, Fig. 4.4).Sample is from lower stope, French mine.Plate 4.24: Thin centimetre scale aphyric basalt sill (unit 7: Fig. 4.4) within structureless Hedleyformation siltstone (unit 2). Photograph is from lower stope in the French mine.81J )82I ) / I I-—--•4. I7 --, Iz /y(5750 / ‘N ( S7500A AL ) \ /,“ / OOD HOPE// / - MINEs’ro o ) N.. sioooir / - / 42CJ/—_*1 4_) -512: / S1250(— I___/ IO)FRENCH MINESFig re 4.3 °?‘ °S15 ) S10/.--.- /‘ / 49C ,// I §Figure 4.6: Plot of sample locations for whole rock chemical analysis (W: Tables C.3 and C.4).QAM1t GRNflJRtTE 1aLtT2.5S’YtNITC SYDrtE. 9 .JH]rTIt 20 ) 40 50 60 10 00 90 iuOonorthfte/(onorthlte + orthoc(se)Figure 4.7: Chemical composition of Hedley intrusions (unit 7) French Mine area, south-central BritishColumbia. Analyses of Table C.3 are plotted on a normative diagram (Streckeisen and LeMaitre,1979). Open squares = aphyric basalt; crosses = homblende phyric basalt; circles quartzdiorite; triangles = Copper Mountain stock.Figure 4.8: Total alkali vs. silica plot (compositional fields defined by Middlemost, 1985) of phyricHedley intrusions from the French mine area, south-central British Columbia. Analyses fromTable C.3 suggest that compositions vaiy from monzodiorite to quartz diorite and quartzmonzodiorite. Circles quartz diorite; triangle = Copper Mountain stock. However, addition ofNa20from alteration is suspected (see text).8304,of0N4,0N4.,L0:501510C’,1-C’,050 60 ;o 70 9084samples collected from sills and stocks west of the French- Good Hope mine area, which plot in thequartz diorite field (average of 27 analysis = 3.2%). This elevation in Na20likely reflects albitizationassociated with skarn alteration and does not necessarily represent a change in magma chemistry withinthe district.Hornblende phyric and aphyric basalt intrusions (field names) plot mainly in the basalt andandesite fields in Figure 4.9 (Winchester and Floyd, 1977). One sample of aphyric basalt plots on the lineseparating the subalkaline basalt field from the alkaline basalt field.Most samples on a TAS diagram are subalkaline (Fig. 4.10: Irvine and Baragar, 1971), however,two samples of hornblende phyric basalt plot in the alkaline field. They are similar to a sample from theCopper Mountain stock, a Late Triassic to Early Jurassic alkalic body spatially associated with porphyryCu-Au mineralization, approximately 40 km to the west. However, all subalkalic samples in Figure 4.10are calcalkaline on a total alkali, total iron and magnesium (AFM) diagram (Fig. 4.11: Irvine andBarager, 1985).Samples were plotted on tectonic discrimination diagrams constructed for volcanic rocks. Mostplots indicate the Hedley intrusions are similar to calcalkaline basalts common to arc environments. Onthe TiJlOO - Zr - *3 triangular diagram (Fig. 4.12: Pearce and Cann, 1973) samples plot mainly in thecalcalkaline basalt (CAB) and island arc basalt (lAB) field; however, some samples plot in the withinplate basalt (WPB) field. On the TiIlOO - Zr - Sr/2 triangular diagram (Fig. 4.13: Pearce and Cairn, 1973)samples plot in both the CAB and JAB field.4.3.3 DiscussionHedley intrusions form a texturally diverse suite of intermediate to malic calcalkaline rocks. Agerelationships between the quartz diorite and the hornblende phyric and aphyric intrusions is problematic.It is not known whether the quartz diorite represents a magma pulse from a more crystallized portion of8580757065- 60Cu504540Figure 4.9: Si02 vs. log (Zr/Ti02)plot (Winchester and Floyd, 1977) of homblende phyric and aphyricHedley intrusion from the French mine area, south-central British Columbia. This plot ofanalyses from Table C.3 suggest that both these units are andesitic basalt. Open squares =aphyric basalt; crosses = hornblende phyric basalt.Cu-4-CU70 75 80 85Figure 4.10: Total aficali vs. silica plot (TAS: Irvine and Barager, 1971) of phyric and aphyric Hedleyintrusions from the French mine area, south-central British Columbia. Analyses from Table C.3indicate that both these units are generally subalkalic. Some aphyric basalt, hornblende phyricbasalt and quartz diorite analyses straddle the alkalic boundaiy. Open squares = aphyric basalt;crosses = hornblende phyric basalt; circles = quartz diorite; triangle = Copper Mountain stock.Zr /1TO2 1 10181614121035 40 45 50 5[P tX)86N2D + K?OFeD’Figure 4.11: AFM diagram (Irvine and Baragar, 1971) of subalkalic phyric and aphyric Hedley intrusionsfrom the French mine area, south-central British Columbia. Analyses from Table C.3 indicatethat both units are, overall, calcalkaline (cf Figs 4.10 and 4.11). Open squares aphyric basalt;crosses = hornblende phyric basalt; circles = quartz diorite; triangles = Copper Mountain stock.Zr Y’3Figure 4.12: Triaxial Ti/100 - Zr - Y*3 plot (Pearce and Cann, 1973) of phyric and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia. Analyses from Table C.3indicate that overall, the units have a calcalkaline signature (cf Fig. 4.9). Open squares aphyricbasalt; crosses = hornblende phyric basalt; circles = quartz diorite; triangles = Copper Mountainstock.MgOT / 100Bsat87Sr / 2Figure 4.13: Triaxial TiJ100 - Zr - Sr/2 plot (Pearce and Cairn, 1973) of phyric and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia. Analyses from Table C.3indicate that overall, the units have a calcaikaline island arc basalt signature (cf Figs. 4.9 to4.12). Open squares = aphyric basalt; crosses = hornblende phyric basalt; circles = quartz diorite;triangles = Copper Mountain stock.n / 100Zr88the same magma chamber as the hornblende phyric and aphyric basalt, or represents a magma pulse froman unrelated magma chamber.The identification of the aphyric basalt units as intrusive and intimately associated with skamalteration is significant in that these units were mapped by previous workers as hornfelsed sediment, tuffor flows. Because gold skarn mineralization is intimately related to aphyric basalt sills, and related stocksor dykes, this new interpretation has important implications as to the timing and depth of skarn formationat the French mine and at other skarn deposits in the Hedley camp. Additionally, this interpretation maybe important in regional skarn exploration programs where a mineralizing intrusion has not beenidentified.Aphyric basalt sills at the French mine exhibit a number of features that support intrusion of wetunconsolidated to poorly consolidated Hedley formation sediment. Features described in Section 4.3.1include: (i) destruction of sedimentary structures, (ii) wavy sill contacts, (iii) globular peperite, (iv)quench textures, and (v) sedimentary dykes. Experimental studies documenting these phenomena arelacking. However theoretical studies (Kokelaar, 1982 and 1986) and magma-water experiments (Sheridanand Wohletz, 1983; Wohletz, 1983 and 1986; Wohletz and MCQueen, 1984a and 1984b) involvingdifferent water to melt ratios, explain different types of interactions, contact configurations and clast types.It is assumed here that wet sediment with a high water content behaves in a manner similar to themagma-water experiments.Intrusion into wet sediment is accomplished by local fluidization of sediment and subsequentremoval of pore water as steam (Kokelaar, 1982). Fluidization is “the mixing of gas and loose fine grainedmaterial so that the whole flows like a fluid” (Reynolds, 1954; Bates and Jackson, 1987). It requires acertain minimum vapor flow velocity and is dependent on vapour density, sediment particle size andparticle size distribution (Kokelaar, 1982). Precise conditions under which fluidization takes place aredifficult to determine; however, expansion of the liquid responsible for fluidization decreases towards thecritical point for water. For seawater, the critical point is 312 bars (assuming 3.45% solutes that are 100%NaCl). This is equivalent to 3.1 km of seawater or 1.6 km of wet sediment (assuming a density of 2g/cm3;Kokelaar, 1982). At a pressure greater than the critical point for seawater, expansion to dense89supercritical vapour is only moderate. In such a case, there would be no fluidization, because the vapourpressure would be insufficient to overcome the ambient hydrostatic pressure caused by the overlyingsediment and water column. Vapour flow as a result of temperature and pressure gradients entrains andmoves sediment laterally along the sill contact until the vapour condenses, at which point the sediment isdeposited. Room for the sill is made by transport of sediment along the sill margin and by water removedas steam (Kokelaar, 1982).Magma that comes into contact with wet sediment, therefore, can form steam bubbles thatcoalesce along the contact to form a thin vapour film. This vapour film is metastable, expanding andcontracting on a millisecond or microsecond scale. Such an oscillating film may remain hydrodynamicallystable and insulate the magma from the wet sediment, thus preventing hydroclastic fragmentation bythermal shocking caused by rapid contraction upon cooling. However, if enough heat energy is transferredto the vapour film, differences in density between the wet sediment, vapour film and magma can producea number of instabilities. Three recogiiized instabilities have been termed: (i) Landua, (ii) Taylor, and (iii)Kelvin-Helmholtz (cf Wohletz, 1986). Instabilities lead to the bulk mixing of magma and wet sediment.If the distortion of the magma surface is sufliciently violent, the magma may detach from the sill to formclasts (globular peperite) in the surrounding sediment (Fig. 4. 16a). Continued oscillation can produceclasts that are mixed with the fluidized sediment by “oscillation pumping” (Busby-Spera and White,1986). The drop like shape of the globular peperite is a result of surface tension effects; they are bestdeveloped in fine grained, well sorted loosely packed sediment where grain by grain entrainment of theenclosing sediment can occur within the vapour film. Globular peperites are more often basalt incomposition because they have a low viscosity, and are more easily detached and mixed with the fluidizedsediment than higher viscosity magmas such as rhyolite.Globular peperite, similar to the interpreted exposure in the French mine workings (Plate 4.18),are interpreted by Busby-Spera and White (1987) to be an example of a fuel-coolant interaction (FCI); finegrained sedimentary particles are viewed as accidental components of the fluid. Fuel coolant interactionsresult from hot fluid (fuel) coming into contact with a cooler liquid (coolant) whose vaporizationtemperature is less that the fuel temperature. FCI’s range from nonexplosive vapourization of coolant90along the coolant - fuel interface, to highly explosive interactions. In the later case rapid mixing of thefuel and coolant is accompanied by rapid exchange of heat between the fuel and coolant. This causessudden vaporization of the coolant and explosive disruption of the system. Most research on FCPs hasfocused on developing fluid instability and detonation theories for rapid boiling processes that lead tohazardous conditions in nuclear reactors, liquid natural gas, and pulp and metal smelter industries(Wohletz, 1986).The complex, irregular, wavy and bulbous sill-sediment contacts observed at the French mine(Plate 4.18) are thought to be caused by the above instabilities and by the low viscosity of the basalticmagma. The highly fluidized Hedley formation sediment allowed protrusions of the magma in anydirection into the sediment (Plate 4.17). Lack of intimate intermixing of magma and wet sediment alongmost sill contacts suggest one or more of the following: (i) the sediment contained insufficient water, (ii)the overlying hydrostatic and/or lithostatic pressure was too high, or (iii) the magma solidffied beforeglobular peperite could form. What is interpreted as globular peperite can be observed at the French minealong one sill contact (Plate 4.18) and along the Princeton Portal road (1 km west) where Hedley quartzdiorite forms a sill complex that is exposed over a distance of 1 000 m (Plate 3.8). Sediment reconstitutionby fluidization surrounding the aphyric basalt sills may have caused the normally thinly laminated Hedleyformation siltstone to be structureless (white rims in Plates 4.17 and 4.24).Thin centimeter-scale sills or dykes up to 0.5 m long are extruded from larger metre-scale bodiesunderground at the French mine (Plate 4.24). Steam moving away from the larger sill or dyke contact intosediment allows thin stringers of magma within the outward rushing fluidized sediment to form these thinintrusions. In such cases, steam does not leave the sill-sediment interface until the host being penetrated isnear the boiling temperature appropriate for that depth; when boiling in the host occurs the vapourimmediately condenses (Kokelaar, 1982).Flow banding was observed at thin section scale at the margins of some sills (Plate 4.19). It islikely a result of continued movement accompanied by addition of magma within the sill interior duringsolidification of the sill margin.91Microveinlets and vesicles of quartz cutting the sills are interpreted to be fluidized Hedleyformation siltstone dykelets injected along fractures formed when the protective vapour film was disrupted(Plate 4.23). Quenching combined with continued magma movement in the sill interior resulted infracturing of the sill margin. Injection of fluidized siltstone into low pressure fractures may be responsiblefor these sedimentary dykelets.Quench, skeletal plagioclase textures (Plates 4.21 and 4.22) are common in rift environmentssuch as mid-oceanic ridges or marginal basins where magma is intruded along fractures into water orunconsolidated wet sediment (Wilson, 1989; Busby-Spera and White, 1987). Crystals develop surface tovolume ratios that are dependent on the growth and diffusion rate allowed by the physical conditionsaccompanying crystallization (Bryan, 1972). Growth of plagioclase in quench glass (aphyric basalt sills)occurs under supercooled conditions in which the high viscosity of the melt significantly reduces thediffusion rate. Under these conditions, the ratio of the diffusion rate of the solute atoms in the liquid to thegrowth rate of the crystal is significantly less than unity. According to the theory of spherulite growth(Keith and Padden, 1963) as applied to silicate systems (Lofgren, 1971b), the most efficient growth formis one in which the surface to volume ratio is a maximum; which results in the skeletal plagioclasecrystals observed in some sills. These observations agree with experimental work by Lofgren (1974) andLofgren and Donaldson (1975) where plagioclase morphology is described as a function of diffusion andgrowth rates.4.4 Alteration and mineralization at the French mine4.4.1 Skarn association with sills and dykesGold skarn mineralization is spatially and temporally associated with phyric and aphyric Hedleyintrusions hosted within limestone and siltstone of the Hedley formation. Skarn alteration is zonedoutward at the centimetre to metre scale from aphyric and hornblende phyric basalt sill or dyke contactsand is strongly dependent on protolith composition. Except for some pillars in the lower stope, most of the92economic gold skarn was removed during mining. Therefore, the overall mineralogical zonation acrossthe deposit is unknown. Individual skarn zones appear to be contained within box like zones formedbetween sills, and close to sill and intersections with dykes (Fig. 4. 16b). Sulphide mineralization isgenerally <1%, however along the French fault and in skarn zones up to 50 m east of the fault, sulphidemineralization is >5% and comprises mainly bornite and chalcopyrite. Historically, this higher sulphidemineralization--called the ‘West Copper Zone--was not mined because it consumed cyanide, whichlowered precious metal recoveries in the milling process (Sharp, 1976).Hedley formation in the vicinity of the French mine (Fig. 4.4) strikes east and dips gently north.Mine workings (Figs. 4.4 and 4.5) consist of two bedding parallel stopes that are open to surface andaccessed by three haulage adits (Kelowna, Cariboo and Granby). Stopes up to 225 m long and 2-15 mhigh extend from surface to 90 m down dip. They generally dip shallowly to the north. However, wheresills apparently step-up stratigraphy the stopes are steeper. The two main stopes are separated by 2-8 m ofbiotite-rich aphyric Hedley sills and unmineralized Hedley formation sediment. Copperfield brecciacommonly forms the back of the upper stope. Mineralization is terminated against the steep French faulton the west, and bottoms on, or is cut off on the east, by the moderate (400) west dipping Cariboo fault(Fig. 4.4). Other northeast faults identified underground have displaced mineralization by <3 m.Skarn in the French mine can be classified as: (I) endoskarn, formed within the aphyric or phyricintrusions, or (ii) exoskarn, formed in the carbonate rich sediments adjacent to the sills. The features ofthese types of skarn are detailed below.4.4.2 EndoskarnPhyric and aphyric Hedley intrusions exhibit varying degrees of endoskarn replacement.Endoskarn occurs as: (i) pervasive biotitization, and as successive mineralogical envelopes formed around(ii) microveinlets, and (iii) margins of aphyric intrusions.93Pervasive biotitization occurs in a stock like body of quartz diorite that crops out at the Caribooadit and in hornblende phyric and aphyric basalt sills and dykes in and around the French mine (Fig. 4.4).Alteration in the quartz diorite ranges from fine grained brown biotite replacement along hornblendecrystal margins to complete pseudomorphing of the crystal. Associated with this potassic alteration isvariable replacement of the matrix by fine grained albitic plagioclase, orthoclase and quartz resulting in a‘bleached’ appearance to the intrusion. Hornblende phyric and aphyric basalt intrusions are overprinted byfine grained brown biotite that gives these rocks a dark purplish brown colour (Plate 4.15), which iscommon to many hornfelsic rocks.Microveinlets with successive mineralogical envelopes cross-cut the pervasive biotite alterationin the hornblende phyric and aphyric basalt intrusions. The microveinlets (<3 mm) are randomly orientedand consist of chlorite, epidote, clinozoisite, titanite and opaque minerals. Successive mineralogicalenvelopes (<5 cm) around these microveinlets consists of grossular garnet (Ad20-5:Fig. 4.14, TableD.2), clinopyroxene (Hd65-100:Fig. 4.15, Table D.3) and orthoclase (Plate 4.25). The succession ofmineralogical envelopes record changing fluid conditions and interactions through time and space.Consequently, some microveinlets have oniy partially developed mineralogical envelopes. In suchexamples, envelopes about the microveinlet can consist of 1 envelope (orthoclase) or 2 envelopes(orthoclase: outer envelope and clinopyroxene: inner envelope). Locally, where the frequency ofmicroveinlets is high and alteration envelopes encroach on each other, massive orthoclase +clinopyroxene skarn makes protolith identification difficult. The microveinlets, interpreted to have formedduring quenching and fracturing of the intrusion, were subsequently infiltrated by hydrothermal fluidsand/or unconsolidated sediments. Garnet skarn is locally developed where fluidized limestone is injectedinto microfractures (see Section 4.3.1) or where adjacent limestone was affected by the magma during sillintrusion.Margins ofthe aphyric intrusions record a mineralogical zoning that is similar to zoning aroundmicroveinlets. Fine grained pink orthoclase and pale green clinopyroxene form thin parallel envelopes (<3cm) along the margins of the biotitic intrusions, Sills intruding limestone commonly develop a firstenvelope of pale reddish brown garnet parallel to the intrusion margin. Where sills intrude siltstones the94pyADFigure 4.14: Temaiy diagram showing the composition of garnet from skarn at the French mine, south-central British Columbia. Data are from Table D.2. Garnets in samples ND 170 (circles) andGD6.8 (crosses) have an aphyric basalt (unit 7) protolith and samples ND267 (triangles) and8969B (squares) have a limestone (unit 2) protolith. Garnets with the aphyric basalt protolithtend to be more grossular.DIFigure 4.15: Ternary diagram showing the composition of clinopyroxene from skarn at the French mine,south-central British Columbia. Data are from Table D.3. Pyroxenes in samples HD17O (circles)and GD 10.4 (triangles) have an aphyric basalt (unit 7) protolith, and sample 8%9A (crosses) hasa limestone (unit 2) protolith.95Plate 4.25: Microveinlets with successive mineralogical envelopes of pale green clinopyroxene and pinkorthoclase cross-cutting brown biotite altered aphyric Hedley intrusion (unit 7: Fig. 4.4). Notewhere fracture density is high, individual envelopes encroach on each other to form massiveorthoclase + clinopyroxene endoskarn. Sample is from waste dump, French mine.Plate 4.26: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of isotropiceuhedral garnet overprinting clinopyroxene skarned Hedley formation siltstone (unit 2: Fig. 4.4).Sample is from lower stope, French mine.96first envelope along the intrusion margin is clinopyroxene that expands outward into the sediment; thismakes definition of the contact difficult. However, the mineralogical envelopes formed along the intrusionmargin generally mimic the intrusion contact exactly. In some exposures, the sill contact is highlyirregular and so are the corresponding mineralogical envelopes.4.4.3 ExoskarnExoskarn formed by hydrothermal fluids associated with the Hedley intrusions is confined mainlyto the Hedley formation at the French mine and forms a continuum from (i) recrystallization and reaction(bimetasomatic diffusional) skarn developed next to sill margins, and (ii) infiltrational skarn developedalong sill contacts, sill-dyke intersections, fold hinges, and bedding and fracture planes. Reaction skarnsoperate on the centimetre scale and are mainly isochernical in nature (Korzhiniskii, 1965; Thompson,1959; Rose and Burt, 1979; Vidale, 1969). They form by diffusional processes within a pore fluid inresponse to thermal and chemical gradients between different lithological units. Reaction skarns arecharacterized by: (i) pale caic-silicates, (ii) form over a few centimetres to 10’s of centimetres, and (iii)original sedimentary structures are recognizable. Metasomatic infiltrational skarns form by the addition(Fe, Mg, Si, Ai and other cations) and removal (Ca) of constituents by a hydrothermal fluid in response topressure and thermal gradients, such that, the original bulk composition of the rock is changed. They arecharacterized by: (i) dark calc-silicates, (ii) form over 10’s of centimetres to metres, and (iii) originaltextures and sedimentary structures are destroyed.Recrystallization and reaction skarn varies from: (i) recrystallization of siltstone and marble afew centimetres from the sill contact, where the sills are thin and uncommon, to (ii) completerecrystallization of siltstone and limestone beds to fine grained mosaic quartz and coarse grained marble,respectively, where the sills are thick or abundant (Plate 4.24). In some exposures, pale, fine grainedorthoclase + clinopyroxene + garnet skarn forms in impure siliciclastics and limestone laminae or at the97contacts of different lithologic units. In these examples, primary textures such as bedding, clasts, etc., aregenerally preserved.JnJIltrational skarn forms the majority of caic-silicate alteration associated with gold skarnmineralization at the French mine. Fractures and contacts of sills and dykes acted as conduits orimpermeable barriers along vhich hydrothermal fluids--responding to chemical, temperature and pressuregradients--were directed (Fig. 4. 16b, Table 4.1). Pale to medium green, fine grained clinopyroxene (11d65-Hd100:Fig. 4.15, Table D.3) forms along the contact of biotitic aphyric basalt intrusions and in siltstonesadjacent to the intrusion contact. Reaction between the fluids responsible for clinopyroxene deposition andthe biotite rich aphyric sills produced a thin envelope of pale pink orthoclase, as previously described inSection 4.2.2. With time and changing fluid conditions, the outward expanding clinopyroxene zonecommonly changes to darker and presumably more iron rich hedenbergitic pyroxene and dark brownandraditic garnet (Ad50-100:Fig. 4.14, Table D.2). Andraditic garnet (<3 nun) is generally isotropic,subhedral to euhedral and clear to reddish brown in thin section (Plate 4.26). Rare, sector twinned,optically zoned anisotropic andraditic garncts (<2 mm) may be a result of small amounts of water in thecrystal structure (Plate 4.27; Meagher, 1980). In some garnet skarn, calcite ÷ silica + vesuvianite +opaque minerals replaces and/or inlills growth zones along the margin of the crystal and in vugs betweencrystals (Plate 4.28). Other minor minerals identified infilling or replacing these open spaces include:actinolite, titanite, wollastonite, clinozoisite, epidote, chlorite, axinite and scapolite (this study and Lamb,1957). Vesuvianite (<3 mm) occurs as subhedral to euhedral grains replacing garnet crystals (Plate 4.28)and as zoned crystals in veinlets cutting garnet ± clinopyroxene skarn (Plate 4.29). Space between garnetcrystals is apparently created by a volume reduction association with the replacement of limestone bygarnet. Except for minor replacement of clinopyroxene and garnet by actinolite + chlorite + titanite +epidote, most of these hydrous-hydroxyl minerals are confined to vugs or fractures with little or nodestruction of earlier mineral assemblages (Plate 4.31).Opaque minerals generally make up <1% of the gold skarn mineralization, except along or 50 meast of the French fault where sulphides (mainly bornite and chalcopyrite) are >5% of the skarn (WestCopper zone). Gold mineralization in most of the mine is intimately associated with arsenopyrite and— ——.-•-.r-’1- + + ++ + + + -f ++ + + + 4___--t,-—.-,Figure 4.16: Schematic section showing skarn alteration within (endoskarn), and adjacent (exoskarn) tophyric and aphyric biotitic Hedley intrusions, French mine, south-central British Columbia. Linetypes are: solid line = protolith contact, dashed line = interpreted contact, dash-dot line =alteration contact. (a) Intrusion of sills into wet unconsolidated to poorly consolidated sediment.Note the wavy sill contacts and peperite formed along some sill contacts. Abbreviations are: Pmmagma pressure, P1= overlying load of sediment and hydrostatic pressure, and T = tensilestrength of sediment. (b) Alteration envelopes within and adjacent to intrusion contacts formedby hydrothermal fluids moving through calcareous sediments within box like zones between sillsand dykes. Table 4.1 describes the mineralogical envelopes from the enlarged area across thesediment - sill contact (cf Plate 4.25).98‘I Li_iI ‘A ‘I_-I I III’I! II II IPepenteStratgrophy:LI -Hey - baeLI— fonnation - dtatoneHe (onnotion - mestone- —_ + •—; - — -.+ -f + + + ++ + + + -F--__‘-f 7—..d99Table 4.1: Mineralogy of inifitrational skarn within (endoskarn), and adjacent to (exoskarn) biotiticphyric and aphyric Hedley intrusions, French mine, south-central British Columbia.Envelope1 DescriptionA Pale pink, fine grained K-feldspar endoskarn replacement of biotitic aphyric basaltintrusion.B Pale green, fine grained, iron poor clinopyroxene endoskarn replacement ofbiotiticaphyric basalt intrusion.C Pale brown, fine grained iron poor grossular garnet (Ad.<50)endoskarn replacement ofbiotitic aphyric basalt intrusion.1 Dark brown, coarse grained iron rich garnet (Ad50..100)and lesser dark green, iron-richclinopyroxene exoskarn replacement of limestone; garnet crystals commonly areeuhedral, sector twinned and anisotropic.1. See Figure 4.16 and Plate 4.25 for location and character of envelopes.100Plate 4.27: Photomicrograph (transmitted light, crossed polars, field of view = 1.25 inni) of sectortwinned, optically zoned anisotropic garnet (<2 mm). The anisotropic nature of these garnetsmay be caused by minute amounts of water in their ciystal structure. Protolith of this sample isuncertain, but is likely Hedley formation limestone (unit 2: Fig. 4.4). Sample is from lower stope,French mine.Plate 4.28: Photomicrograph (transmitted light, field of view 1.25 mm) of isotropic subhedral toeuhedral garnet with calcite + silica + vesuvianite infiuing growth zones parallel to the crystalmargin. Protolith of this sample is likely Hedley formation limestone (unit 2: Fig. 4.4). Sample isfrom the lower stope, French mine.101Plate 4.29: Photomicrograph (transmitted light, crossed polars, field of view = 5.0 mm) of opticaliy zonedvesuvianite crystals in a vein cross-cutting garnet ± clinopyroxene skarn. Protolith of this sampleis likely Hedley formation limestone (unit 2: Fig. 4.4). Sample is from the lower stope, Frenchmine.Plate 4.30: Photomicrograph (reflected light, field ofview 0.3 00 mm) of chalcopyrite exsolutionlamellae in bornite infilling vugs between garnet crystals. Protolith of the sample is likely Hedleyformation limestone (unit 2: Fig. 4.4). Sample is from the waste dump, French mine.,T.e‘4 1,:.102minor amounts of bismuth tellurides. Limited polished section examination and electon microprobeanalysis of opaque minerals identified the following minerals in decreasing order of abundance:chalcopyrite, bornite, arsenopyrite, pyrrhotite, pyrite, magnetite, covellite, cobaltite, erythrite, malachite,azurite,joseite (Bi4+Te2Swhere x 0-0.3 and may contain some Se and Pb), bismuthinite, nativebismuth and native gold. Minerals not identified in this study, but identified by previous workers include:maldonite, wittichenite, kiaprothite, calcocile, loellingite-safflorite, hedleyite, gersdorfite, scheelite andmolybdenite (Lamb, 1957; Hogan, 1953; Wober, 1990). Bornite (Table D.4) occurs interstitial to and inveins cutting garnet skarn in the West Copper zone. Chalcopyrite occurs as exsolution lamellae in or asmargins to the bornite (Plate 4.30). Arsenopyrite is subhedral to euhedral and commonly contains veryfine grained inclusions. Visible gold (Au7993:Table D.5), joseiteb and bismuthinite (Table 4.6),actinolite and calcite infills vugs between iron-rich andraditic garnet (Ad50_100:Table D.3, Plate 4.31).Gold with trace Cu and/or Hg appears to have a higher Au:Ag ratio than where these elements are absent[Table 4.5: 10.4 ± 1.0 (standard deviation) vs. 4.0]. At least two populations of gold fineness areindicated. Note that gold is from the same sample but that the two grains analyzed are different.4.4.4 DiscussionHydrothermal fluids moved through box like zones between impermeable dykes and sills or alongfractures and bedding planes. As a result of temperature and pressure gradients a number of expandingcontemporaneous alteration fronts responsible for the observed mineralogical zoning were produced(Fig.4.16b, Table 4.1). Infiltrational skarns (Korzhiniskii, 1965, Thompson, 1959) are defined below, as(i) endoskarn where formed in an aphyric basalt protolith, and (ii) exoskarn where formed in thesedimentary units.Gradients in the composition of the hydrothermal fluid at each zonal front in the infiltrationalskarn is reflected in a distinct mineralogical zonation. At the French mine, the skarn displays a consistent103Plate 4.31: Photomicrograph (reflected light, field of view 5.0 mm) of gold (Au: Au7993,joseite (J),bismuthinite (B), actinolite (A), and calcite (C) infilling vugs between garnet (G) crystals.Protolith of the sample is Hedley formation limestone (unit 2: Fig. 4.4). Sample is from lowerstope, French mine.104mineralogical zoning from aphyric basalt to orthoclase endoskarn, Mg-rich clinopyroxene endoskarn, Fe-rich clinopyroxene endoskarn and exoskarn (spans the aphyric basalt - limestone contact) and Fe-richgarnet exoskarn. Minerals within each zone have nearly constant compositions because chemicalgradients in the fluid within each zone are weak or absent (mosaic equilibrium of Thompson, 1959).Initial hydrothermal fluids moving along microfractures or intrusion margins remove iron and magnesiumfrom biotite to form orthoclase. As the concentration of iron and magnesium increases in thehydrothermal fluid, diopsidic pyroxene is deposited to form the next mineralogical envelope becausemagnesium is more strongly partitioned into the silicate phase than iron at higher temperatures (Eugsterand Ilton, 1983). With time, the fluid becomes cooler and more iron-rich, and hedenbergitic pyroxeneand/or andraditic garnet are deposited to form the innermost envelope of the microfracture, or theoutermost envelope from the intrusion margin. In addition to fluid conditions (composition, temperatureand pressure), the protolith has an important influence on mineral composition. Early, pale brown garnetsreplacing aphyric basalt intrusion are typically aluminum-rich grossular (Ad2050:Fig. 4.14, Table D.2),whereas later, darker brown garnets replacing marble are iron-rich andradite (Ad50100:Fig. 4.14, TableD.2).As the hydrothermal fluids cooled, quartz, calcite, hydrous-hydroxyl minerals, suiphides,tellurides and associated gold were deposited in microfractures to form microveinlets or to infill vugsbetween the Fe-rich garnet ± pyroxene skarn. Vugs, probably created by volume reduction associated withformation of the infiltrational skarn, are greatest in limestone. Volume changes associated withmetasomatic processes at the Nickel Plate deposit (Wagner, 1989) suggest that the siliciclastic andlimestone units underwent volume reductions of 30-65% and 80%, respectively. Studies to veri1 thesesubstantial volume reductions during skarn alteration are currently in progress (1991) at the University ofWaterloo (Dr. E.C. Appleyard, personal communication to G.E. Ray). This may be largely responsible forthe lithological control to suiphide and associated gold mineralization. Additionally, the more reducedhedenbergite skarn would locally buffer hydrothermal fluids causing the precipitation of these lowertemperature minerals. Iron depleted hydrothermal fluids caused by precipitation of iron-rich pyroxene andgarnet may be responsible for the low sulphur content minerals such as bornite and pyrrhotite. There is a105close spatial association between arsenopyrite, tellurides, vesuvianite, scapolite and gold. This suggeststhat arsenic, tellurium and chlorine may be important complex forming elements in the transportation ofgold in the French skam system. The above mineralogical zoning is complicated locally by cross-cuttinghydrothermal overprinting.Retrograde alteration is negligible. This may indicate that the hydrothermal system cooledrelatively quickly through the temperature range that these minerals ciystallized at, allowing insufficienttime for replacement of surrounding skarn assemblages. The rapid cooling of the hydrothermal system isconsistent with the shallow environment envision for the intrusion of Hedley sills into wet unconsolidatedto poorly consolidated sediment.Relevant modern day analogies to the French mine skarn occur in the Atlantic II Deep, Red Sea(Zierenberg and Shanks, 1983), and the Guaymas Basin, Gulf of California (Einsele et at., 1980). In theAtlantis II Deep, an assemblage of hematite + magnetite + pyroxene (solid solution between acmite,diopside and hedenbergite) with minor amounts of actinolite, ilvaite, albite (An0_40), quartz, chalcopyrite,anhydrite, smectite, talc, chlorite, sphene and andraditic garnet occur in unconsolidated sediments close tobasalt sills. Minor amounts of actinolite form overgrowths on the surface of the pyroxene grains, andapparently precipitated late in the paragenetic sequence. In the Guaymas Basin, an assemblage of epidote,albite and chlorite occurs near sills but is thought to be related to a longer lived heat source at depth.106CHAPTER 5.0 CONCLUSIONSThe Hedley camp in south-central British Columbia contains a number of economicallysignificant gold skarns. Although gold skarns have been mined in the Hedley camp since the early 1900’s,little was published on them and they were not recognized as a distinct class of ore deposit in the review ofskarns by Einaudi et al., 1981. However, since that time a number of discoveries such as Fortitude (Myersand Meinert, 1991), McCoy (Brooks eta!., 1991), Crown Jewel (Hickey, 1990), and the reopening ofNickel Plate (Ray et al., 1986) has resulted in these deposits being recognized as important sources of goldand viable exploration targets.In this study, the geological setting of the Hedley camp has been outlined and the lithologic,stratigraphic and structural controls to gold skarns in the camp have been discussed (Section 5.1).Alteration and mineralization around one of these skarns--French Mine--is described (Sections 5.2 and5.3). Finally, a model for Hedley-type gold skarns is presented (Section 5.4) that links skarn generation toformation of a sill sediment complex.5.1 Geological setting of the Hedley gold skarn campThe Hedley gold skarn camp in south-central B.C. occurs along the eastern rifted margin of amarginal basin east of the main Nicola arc in Quesnellia. Rocks in this basin are predominantlysedimentary facies of the Late Triassic Nicola Group (Figs. 1.1 and 3.18: units 2-6) and synsedimentaryintrusions (unit 7). These unconformably overlie more deformed oceanic rocks of the Middle to LatePaleozoic Apex Mountain complex (unit 1). West of Hedley, much of this basin is obscured by Jurassic(units 8-12) and Cretaceous intrusions.The Nicola Group is subdivided into four sedimentary and one volcaniclastic formation. Thethree youngest sedimentary formations, based on Late Triassic conodonts (Carnian to Norian: M.J.Orchard, written communication, 1988) and paleocurrent indicators, are facies equivalents representing107deposition across a north trending, westward deepening, fault controlled basin margin. They arerepresented by: (i) siltstones and thick limestones as the shallow water Hedley formation (Fig. 3.17: unit2), (ii) siltstones and thin limestones as the intermediate depth Chuchuwayha formation (unit 3), and (iii)argillite and rare limestone as the deeper water Stemwinder formation (unit 4). Collapse of this basin ismarked by the deposition of the Copperfield breccia (unit 5) which separates the Hedley, Chuchuwayhaand Stemwinder formations from the overlying volcaniclastics of the Whistle formation (unit 6). TheCopperfield breccia is a limestone breccia that appears to represent a catastrophic massive gravity slidedeposit derived from uplifted and faulted reef material with a provenance to the east. Seismic shockrelated to earthquakes associated with the start of volcanism may have been responsible for the generationof this unit. The overlying Whistle formation forms an extensive unit that grades from thinly laminatedtuffaceous siltstones at its base, to massive intermediate to mafic ash and lapilli tuffs. The tuffs aresubalkalic and alkalic, and have an island arc trace element signature. Absence of facies changes andlimestone units, and the change from thinly laminated turbiditic sediments to thick bedded airfallvolcanics in the Whistle formation suggests that sea floor topography varied from a fault bounded basin toa relatively smooth featureless surface after deposition of the Copperfield breccia.Three intrusive episodes recognized in the Hedley area are: (i) Late Triassic Hedley intrusions(Fig. 1.1: unit 7), (ii) Early Jurassic Bromley batholith (unit 8) and Mount Riordan stock unit 9), and (iii)Middle Jurassic Cahill Creek pluton (unit 10), Lookout Ridge pluton (unit 11), rhyolite porphyry dykes(unit 12) and their extrusive equivalent, Skwel Peken formation (unit 13).Hedley intrusions (Fig. 1.1: unit 7) occur as quartz diorite to gabbro dykes, sills and stocks.Chemically they overall are calcalkaline and have an island arc trace element signature. Stocks and dykesoccur throughout the Nicola Group; however sills are best developed in the shallow water Hedleyformation where they form a sill complex centered about the Toronto stock. It is uncertain if the Torontostock represents a composite body consisting of numerous dykes that fed the adjacent sills or if the stockwas intruded as one large body with numerous apophyses that form sills in the adjacent sediments;however, the former interpretation is preferred. The sills, exposed over a vertical distance of 1 000 m,make up to 40% of the stratigraphy, and arc spatially and temporally associated with gold skarn108mineralization. The sills are commonly thin (<2 in) where they intrude thinly bedded limestone andsiltstone, but are thick (75 m) where they intrude thick bedded limestone. Individual sill contacts varyfrom planar to highly irregular, and rarely, are brecciated. The indicated Late Triassic age of the sills(maximum age of 217.5 ± 4.2 Ma, 3. Gabites, written communication, 1993; minimum age of 193 ± 1 Mabased on cross-cutting relationships with the Bromley batholith), and the above morphological features,suggest they were emplaced into unconsolidated siltstone units that occur between limestones thatdiagenetically lithified quickly after deposition. Lack of sills in the Stemwinder formation may have beena function of the increased lithostatic and hydrostatic pressure associated with a thicker sedimentary pileand deeper water.The Early Jurassic Bromley batholith (Fig. 1.1, unit 8: 193 ± 1 Ma, Parrish and Monger, 1991)and a satellite body called the Mount Riordan stock (Fig. 1.1, unit 9: 194.4 ± 3.8 Ma, 3. Gabites, writtencommunication, 1993) are calcalkaline granodiorite to tonalite. The Mount Riordan stock is spatially andtemporally related to Cu-W mineralization and industrial garnet skarn on Mount Riordan.The Middle Jurassic Cahill Creek pluton (Fig. 1.1, unit 10: 170.0 ± 9 Ma, 3. Gabites, writtencommunication, 1993) is calcalkaline, quartz monzonite to granodiorite and commonly separates theNicola Group from the underlying Apex Mountain complex. The lacolith like shape in cross-sectionsuggests that the intrusion rose diapirically to the Nicola Group - Apex Mountain complex unconformitywhere it intruded laterally. Aplite phases at the top of the stock and dykes in the surrounding countryrocks formed as the main body crystallized. Minor W-Mo porphyry style mineralization is spatially andtemporally associated with the aplite. Rhyolite porphyry dykes (unit 12: 155 ± 10 Ma, 3. Gabites, writtencommunication, 1993) presumably represent feeders between the deeper level Cahill Creek pluton and theSkwel Peken formation. The Skwel Peken formation consists of a lower unit of massive to bedded dacitictuff (unit 13a: maximum age of 186 ± 11 Ma, J, Gabites, written communication, 1993) and an upper unitof massive feldspar phyric andesite tuff (unit I 3b) that unconformably overlies the Nicola Group. Theformation is interpreted to have been deposited in a non-marine, shallow water to subaerial environment.Nicola Group rocks record Late Triassic extensional and Lower Jurassic to Cretaceouscompressional histories. Northeasterly striking normal faults and west-northwesterly striking fracture109zones are products of Late Triassic extension. The major normal faults from east to west are the CahillCreek, Bradshaw and Chuchuwayha faults. Displacement on these faults during Late Triassic (Carnian toNorian) time formed a stepped seafloor of successively westward down dropped blocks. This is reflectedby the successively deepening facies changes represented in the Hedley, Chuchuwayha and Stemwinderformations. West-northwesterly striking fracture zones may reflect transform faults along which somedykes and stocks of Hedley intrusion were emplaced.Structures associate with Lower Jurassic to Cretaceous compression include a district wideanticline called the Hedley anticline, asymetric minor folds, reverse faults, and possibly, easterly directedthrust faults. The axial plane of the Hedley anticline strikes northeast and dips steeply west; its trace liesalong Cahill Creek just east of Nickel Plate mine. Asymetric minor folds on the Hedley anticline occurthroughout the district. Reverse faults mark compressional reactivation of many of the Late Triassicnormal faults. Duplex like structures observed northwest of Hedley township, and west dipping low anglefaults mapped underground at the Nickel Plate and French mine may reflect easterly directed thrust faults.Galena lead isotope ratios from the Nickel Plate gold skarn mine were compared with the CopperMountain copper - gold porphyry deposit. In general, the galena lead isotopes from both deposits are verysimilar and plot between upper crustal lead characterized by the shale curve and mantle lead. This isindicative of lead mixed between reservoirs in an orogene or island arc setting. Present framework modelsdo not appear to characterize the lead, and therefore, the age of the deposits cannot be determined fromgalena lead isotopes. Copper Mountain lead is slightly more primitive than Nickel Plate lead suggesting it,comparatively, had less access to upper crustal components.5.2 Geological setting of the French mine gold skarnThe French mine occurs east of the Cahill Creek fault along the eastern rifled margin of thenorth trending elongate Nicola back-arc basin. In this area, the Late Triassic Nicola Group (Fig. 4.1: units1102, 5 and 6) forms a northeast striking, shallow dipping sequence that unconformably overlays stronglydeformed oceanic rocks of the Middle to Late Paleozoic Apex Mountain complex (unit 1).Apex Mountain complex (Fig. 4.1: unit 1) consists of siliciclastics, andesite to basalt volcanicsand subvolcanic intrusions, and minor chert pebble conglomerate, chert, limestone and ultramafic rock.Bedding in these units strikes northeast and dips steeply east and west; the best fit girdle of poles tobedding strikes 313° and dips 82° southwest suggesting shallowly northeast plunging folds.Nicola Group consists of the Hedley formation (Fig 4.1: unit 2), Copperfield breccia (unit 5) andWhistle formation (unit 6). Bedding in these units strikes 226° and dips shallowly west; locally at theFrench mine, bedding strikes east-northeast and dips shallowly (300) north. The Hedley formation forms athin (<50 m) discontinuous unit of interbedded siltstone, limestone and minor argillite preserved inpaleotopographic lows along the westerly sloping basin edge. West of the Cahill Creek fault, this unitdramatically thickens to over 500 m where it hosts gold skarn mineralization at the Nickel Plate deposit.Copperfield breccia is 10 - 100 m thick and overlies the Hedley formation and Apex Mountain complex. Itconsists of massive to bedded limestone breccia and conglomerate with minor interbeds of thinlylaminated limestone. Whistle formation forms a 200 m thick unit that conformably overlays theCopperfield breccia. It consists of interbedded tuffliceous siltstone that grade into massive andesite tobasaltic ash and lapilli luff.Two intrusive episodes are recognized in the French mine area. These are: (i) Late TriassicHedley intrusions (Fig. 4.1: unit 7), and (ii) Middle Jurassic Cahill Creek pluton (unit 10) and rhyoliteporphyiy dykes (unit 12).Hedley intrusions (Fig. 4.1: unit 7) form a texturally diverse suite of intermediate to maficcalcailcaline dykes, sills and stock like bodies that are spatially and temporally associated with gold skarnmineralization. Phyric intrusions consist of quartz diorite and hornblende basalt porphyries. The aphyricintrusions, previously mapped as horufelsed tuffaceous sediments, form thin basalt sills, dykes or marginsto hornblende phyric basalt porphyries. The homblende phyric and aphyric intrusions are unique to theFrench mine area. It is uncertain if the quartz diorite represents a magma pulse from a more crystallizedportion of the same magma chamber as the hornblende phyric and aphyric basalt, or represents a magma111pulse from an unrelated magma chamber. Features such as wavy sill contacts, destruction of sedimentarystructures, globular peperite, quench textures and sedimentary dykes suggest that the aphyric basalt sillsintruded wet unconsolidated to poorly consolidated siltstone and limestone of the Hedley formation. Thisinterpretation implies that the Hedley formation, Hedley intrusions and associated gold skarn areessentially contemporaneous and form at re!atively shallow depths.Cahill Creek pluton (Fig. 4.1: unit 10) forms a sheet like body in the French mine area thatintrudes at or near the Nicola Group - Apex Mountain complex unconformity. Contact metamorphism hasaltered the siliciclastics in the Apex Mountain complex, below and east of the pluton, to biotite +cordierite + garnet. The limestone breccia (Copperfield breccia) and tuffaceous siltstone (Whistleformation) of the Nicola Group above the pluton have been altered to caic-silicate reaction skarn. Thepluton is medium grained, equigranular, biotite-hornblende granodiorite to monzodiorite; minor aplitephases form along the upper contact and as dykes in the surrounding country rocks. W-Mo mineralizationassociated with this intrusion forms disseminations and veins of quartz ± actinolite, epidote, molybdeniteand scheelite in the aplite and adjacent country rocks. The close proximity of the French and Good Hopemines to the upper contact of the Cahill Creek plu ton apparently caused the earlier gold skarn to beoverprinted by this W-Mo mineralization.Rhyolite porphyry dykes (Fig. 4.1: unit 12) are isolated and thin (<3 m thick). They areinterpreted to be feeders between the deeper level Cahill Creek pluton and the overlying Skwel Pekenformation volcanics that crop out on Lookout Mountain, which is 7 km north of the French mine.5.3 Gold skarn mineralization of the French mineGold skarn mineralization at the French mine is hosted in siliciclastics and limestone of theHedley formation (Fig. 4.3: unit 2). Skarn can be classified as endoskarn and exoskarn. Most gold occursin infikrational exoskarn. Mine workings consist of two bedding-parallel stopes that are separated bybiotite rich aphyric Hedley sills or unaltered Hedley formation (Fig. 4.4). Copperfield breccia conunonly112forms the back of the upper stope. Mineralization is terminated against the steep French fault on the west,and bottoms on, or is cut off on the east by the shallowly west dipping Cariboo fault.Endoskarn consists of: (i) pervasive biotitization and successive mineralogical envelopes formedaround (ii) microveinlets and (iii) intrusion nmrgins. The microveinlets are randomly oriented and consistof: chlorite, epidote, clinozoisite, titanite and opaque minerals. Successive mineralogical envelopes aroundthese microveinlets consist of iron-poor grossular garnet, clinopyroxene and orthoclase. The microveinletsare interpreted to have formed along fractures that were generated by quenching during intrusion and thatwere subsequently infiltrated by hydrothermal fluids and/or fluidized sediment. Garnet skarn is bestdeveloped where fluidized limestone is injected into microfractures or where limestone was ingested bythe magma during sill intrusion. Margins of the aphyric intrusions have a similar mineralogical zoning asthe microveinlets. Fine grained orthoclase and clinopyroxene form thin (<10 cm) parallel envelopes alongthe margins of the biotitic intrusions. Sills intruding limestone commonly develop garnet envelopes (<50cm). However, where sills intrude siltstone the clinopyroxene envelope along the intrusion marginexpanded outwards (<10 cm) into the sediment making identification of the contact difficult.Exoskarn forms a continuum from: (i) recrystallization and reaction (bimetasomatic diffusional)skarn along intrusion margins, to (ii) metasornatic infiltrational skarn formed along sill contacts, sill-dykeintersections, fold hinges, and bedding and fracture planes. Diffusional skarn varies from: (i)recrystallization a few centimetres from the intrusion margin where the bodies are thin and infrequent, to(ii) complete recrystallization of siltstone and limestone beds forming fine grained mosaic quartz andcoarse grained marble adjacent to thick or abundant sills.Infiltrational exoskarn forms the majority of caic-silicate alteration associated with gold skarnmineralization at the French mine (Fig. 4. 16b, Table 4.1). The skarn displays consistent mineralogicalzoning outward from aphyric basalt to orthoclase endoskarn, Mg-rich clinopyroxene endoskarn, Fe-richclinopyroxene endoskarn and exoskarn (spans the aphyric basalt - limestone contact) and Fe-rich garnetexoskarn. Hydrothermal fluids moving through box like zones between impermeable dykes and sills, oralong fractures and bedding planes as a result of temperature and pressure gradients. A a number ofexpanding contemporaneous alteration fronts produced the observed mineralogical zoning. This113mineralogical zoning is interpreted to be the result of initial hydrothermal fluids removing iron andmagnesium from biotite to form orthoclase from the remaining potassium. As the iron and magnesiumincrease in the hydrothermal fluid, diopsidic pyroxene is deposited to form the next mineralogicalenvelope. This is likely because magnesium is more strongly partitioned into the silicate phase than ironat higher temperatures (Eugster and Ilton, 1983). With time and distance, the iron rich fluids becomecooler and iron-rich hedenbergitic pyroxene andlor andraditic garnet were deposited to form the envelopeoutermost from the intrusion margin. Quartz, calcite, hydrous-hydroxyl minerals, arsenopyrite, copperand iron suiphides, tellurides and associated gold are deposited in microfractures and vugs between iron-rich garnet ± pyroxene skarn as the hydrothermal fluids cooled. Vugs, probably created by volumereduction associated with the infiltrational skarn, are greatest in the limestone and may be responsible forthe lithological control to suiphide and associated gold mineralization. This simple mineralogical zoningis commonly only partially developed. Locally, it is overprinted by subsequent hydrothermal fluids,possibly related to multiple magma pulses associated with sill formation.5.4 Model for Hedley-type gold shamsRegional mapping in the Hedley camp (Ray and Dawson, 1994) and more detailed studies at theNickel Plate Ettlinger eta!., 1992) and French mine (this study) has identified a number of features thatcharacterize Hedley-type gold skarns. These features are:1. The back arc or marginal basin setting is marked by rift related faults along the basin edge thatinfluence sedimentation and guide intrusions into siliciclastics and carbonates.2. Calcalkaline, intermediate to mafic, synsedimentary intrusions directed along these faults intoshallow water siliciclastics and carbonates, formed small stock like bodies, sill complexes andminor dykes. The stock like bodies may be composite in nature and consist of numerous dykesthat fed the adjacent sills. Sill complexes are confined to shallow water environments (<3 km)because in deeper water environments the overlying hydrostatic and lithostatic pressure is greater114than the pressure of the magma; in such cases, magma is confined to fractures as dykes or smallstocks. The sills are commonly thin and numerous in thinly bedded siltstone and limestone, andthick and infrequent in thickly bedded limestone; this suggests that some of the limestones mayhave lithifled quickly after deposition, and thus, excluded intrusion of the sills. The structural,lithological and stratigraphic control of skarns documented in the Hedley camp is a function offeatures outlined above.3. Economic gold skarns apparently are related to the stocks and adjacent sills. Individual sillsacted as impermeable barriers along which hydrothermal fluids moved. However, sill complexes,such as that exposed on Nickel Plate Mountain, indicate areas of high heat flow and proximity toa large heat source that may have added components to skarn formation. Thus, features such assill-dyke intersections, abnipt changes in sill orientation, fractures, small crump1e& related to sillintrusion and close proximity to the marble line (outer boundary of the exoskarn envelope) aresecondary controls to skarn formation.4. Thermal diffusional skarn (hornfels) is characterized by biotite, K-feldspar, quartz, diopsidicpyroxene and grossular garnet; mineralogy is highly dependent on protolith composition.5. Infiltrational skarn consists dominantly of hedenbergitic pyroxene, andraditic garnet and lesseramounts of vesuvianite, scapolite, axinite, calcite, quartz, wollastonite, epidote, actinolite,apatite, titanite, rutile and other trace minerals. Sulphides are typically reduced, low sulphurassemblages of arsenopyrite, pyrrhotite, bornite, chalcopyrite, bismuth tellurides, native gold andbismuth. Suiphides in general make up <10% of the skarn.6. Retrograde alteration is negligible in the Medley gold skarns, which is consistent with theshallow environment of formation envisioned for these skarns.115REFERENCESAllan, IF., Gorton, M.P., Cousens, B.L., and Leg 127 Shipboard Party (1990): Geochemistry andcharacter of rocks collected by ODP Leg 127 from the Yamato Basin, eastern Japan Sea:implications for back-arc spreading processes. GAC-MAC Annual Meeting, Programs withAbstracts, Geological Association of Canada, Vol. 15, p. A2.Andrew, A., Godwin, C.I., and Sinclair, A.J. (1984): Mixing line isochrons: a new interpretation ofgalena lead isotope data from southeastern British Columbia. Economic Geology, Vol. 79, pp.919-932.Andrew, K.P. 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Samples were dissolved in acetic acid in the field and the residues were sent to theGeological Survey of Canada for separation, picking and identification. Conodonts and other microfossilswere recovered from all major stratigraphic units (fable A.1). Samples collected east of the Cahill Creekfault, in the Good Hope - French mine area, are highly altered and no recognizable inicrofossils wererecovered from units in this area. Determinations (written communication, 1988) were by M.J. Orchard(Nicola Group- units 2-5) and E.C. Prosh (Apex Mountain complex), Geological Survey of Canada,Vancouver, British Columbia.130TableA.1:FossildescriptionsandagesofmicrofossilsfromtheApexMountaincomplexandtheNicolaGroup,Hedleyarea,south-centralBritishColumbia.Numberof speciesidentifiedareinbracketsatendof name.Alldeterminations(writtenconununications,1988)werebyM.J.Orchard(NicolaGroup-units2-5)andE.C.Prosh(ApexMountaincomplex-unit1),GeologicalSurveyofCanada,Vancouver,BritishColumbia.FIELDNO.GSCNO.UTMCOORDINATES:UNIT2FOSSILAGEDATE3CAl4MAPNO.1EASTNORTH(Ma)HD-45C-10330070790054705005Bayozoans?, ichthyolithsLateTriassic:2275F1Conodonts:MetapolygnathusCarnianpolygnathiformis(Burdurov&Stefanov)(4)HD-47C-14339870780054704105Ichthyoliths,shellmaterialLateTriassic:2295F2Conodonts:MetapolygnathusnodususprobablyLateCarnianHayashi(2)HD-48C-10372470780054704005PelecypodsLateTriassic:2205F3Conodonts:EpigndolellatriangularislateEarlyNorian(Burdurov)(3)HD-112C-10373570895054727504Conodonts:EpigondolellatriangularisLateTriassic2205F4(Budurov)Neogondolellanaviculalate EarlyNorianHD-135C-10373970823054660754Conodonts:EpigondolellatriagularisLateTriassic:220-5F5(Burdurov)(4);Neogondella?sp. (1)lateEarlyNorianND-49C-10372570790054702504RamiformelementsLateTriassic2115F6Conodonts:EpigondolellabidentataLateNorian(Mosher)(5); Neogondolellasp. (25)1.Mapnumberis plottedonFigure3.1.2.UnitisidentifledinTable3.1andonFigure1.1.3.Timescaleusedisafter Armstrometal.,1988.DateisassignedageusedinFigure3.17.4.CAlis colourindexthatreflectsmetamorphicgrade(Rejebianetal.,1987).5=300-4800C;6=360-550°C;7490-720°C;8=>600°C.TableA.1:FossildescriptionsandagesofmicrofossilsfromtheApexMountaincomplexandtheNicolaGroup,Hedleyarea,south-centralBritishColumbia(continued)...FIELDNO.GSCNO.UTMCOORDINATES:UNIT2FOSSILAGEDATE3CAl4MAPNO.1EASTNORTH(Ma)HD-57C-l0372770950054696954Conodonts:MetapolygnathusnodosusLateTriassic:2285.5F7(Hayashi)(4)LateCarnianHD-51C-14339970800054695404Ramiformelements,ichthyolithsLateTriassic2135Fgspicules,shellmaterialMiddle-LateNorianConodonts:Epigondolellasp.(1)HD-56C-10372670883054695104Conodonts:MetapolygnathusLateTriassic:2285F9M.communisti (Hayashi) (2)1probablyLateCarnianHD-8C-10372871037054714804Conodonts:Mefapolygnathus?sp.(1)LateTriassic:2275F10VprobablyCarnianHD-28C-l0372970918054719954Ramiformelements(1)LateTriassic:2255F11Conodonts:MetapolygnathuspnmutusLateCarnian-Early(Mosher)(3)NorianHD-20C-10372371120254728113Pelecypods,ranüformelements(1)LateTriassic:2205F12Conodont:Epigondolellasp.(3)Early-MiddleNorianHD-19C-l0372271150054725203Ramiformelements(8)LateTriassi:2205F13Conodont:EpigondolellatriagularislateEarlyNorian(Budvrov)(42)TableA.1:FossildescriptionsandagesofmicrofossilsfromtheApexMountaincomplexandtheNicolaGroup,Hedleyarea,south-centralBritishColumbia(continued)...FIELDNO.GSCNO.UTMCOORDINATES:UNiT2FOSSILAGEDATE3CAl4MAPNO.’EASTNORTH(Ma)HD-12C-14339771120054717703SpiculesLateTriassic:2225F14Conodonts:Epigondolellaabneptis(1)EarlyNorianHD-106C-10373271357054702702Conodonts:Epigondoleliasp.(3)LateTriassic:2197-8F15Early-MiddleNorianHD-260C-10374671503054713502IchthyolithsLateTriassic:2205F16Conodonts:Epigondolellaabneptissubsp.lateEarlyNorianAOrchard(4)HD-118C-10373671481054715002IchthyolithsLateTriassic2145.5-6F17Conodonts:Epigondolellaabneptissubsp.A.Orchard(4);Epigondolellatriangularis(Budurov)(5)HD-120C-10373771435054711652IchthyolithsLateTriassic:2196?F18Conodonts:Epigondolellasp.Early-MiddleNorianHD-305C-10375071571054733002SpongespiculesLateTriassic:2225-7F19Conodonts:Epigondolellaabneptissubsp.EarlyNorianA.Orchard(6);Epigondolellatriangularis(Budurov)(11);Metapolygnathussp.(2)TableA.1:Fossildescriptionsandagesof microfossils fromtheApexMountaincomplexandtheNicolaGroup,Hedleyarea,south-central BritishColumbia(continued)....FIELDNO.GSCNO.MAPNO.1UTMCOORDINATES:UNIT2FOSSILAGEDATE3CAl4EASTNORTH(Ma)C-10299671182754702382Ichthyoliths,rantiformelements(1)LateTriassic2226-7F20Conodonts:EpigondolellasabneptisEarlyNorianHuckriede(18)HD-651C-15376071795054622201Brachiopods,tentaculitids, phosphaticDevonian465F21tubes(?)HD-652C-15376171795054622201Tentaculitids(?)Cambrian-Devonian465F22HD-653C-15376271795054622201Brachiopods,tentaculitids(7),phosphaticDevonian465F23tubesFJD-186C-10329971440054615501Ichthyolith(recrystallized)IndeterminateF24HD-46C-14340070780054704101IchthyolithsIndeterminateF25APPENDIX B: Isotopic analyses (U-Pb zircon, K-Ar biotite hornblende and amphibole,and galena lead) from the Hedley area, south-central British Columbia.Appendix B contains infonnation on sampling procedures, analytical methods, and tables of U-Pb zircon analyses of intrusive (units 7, 9, 10 and 12) and tuffaceous (unit 13) rocks from the Hedley area(Ray and Dawson, 1994; Table B.1) and galena lead analyses of mineralization from the Nickel Plate andCopper Mountain mines (this study, Table B.3). Previously published K-Ar (biotite, hornblende andamphibole) and U-Pb (zircon) analyses of intrusive (units 7, 8, 11 and 12) rocks from the Hedley area arein Table B.2. Sample locations are on Figure 3.1.135136U-Pb Zircon AnalysesSampling ProcedureFive samples, each approximately 50 kg, were collected from intrusive and extrusive rocks in theHedley area, south-central British Columbia. Samples were sent to Fipke Laboratories in Kelowna wherethey were crushed and split into various size fractions and magnetic susceptibilities. Zircons from thesesamples were hand picked under a binocular microscope by G.E. Ray and G.L. Dawson. Two additionalsamples of Hedley quartz diorite (unit 7) were collected from the Toronto stock and a stock like body nearthe French mine. These samples were processed at The University of British Columbia similar to themethod described above; however they contained insufficient zircon for analysis.Analytical MethodsAnalysis of zircons were completed at The University of British Columbia by P. Van der Heyden,D. Murphy and 3. Gabites. Some fractions were abraded using air abrasion techniques (Krogh, 1973) toimprove concordance. Chemical dissolution and mass spectrometry are modified from proceduresdescribed by Parrish and Krogh (1987), and employed a mixed 205Pb- 233U- 235U spike. Zircons weredissolved in small volume teflon capsules contained in a large Parr bomb (Parrish, 1987). Both U and Pbwere eluted into the same beaker, and loaded and run together on the same Re filament with silica gel andphosphoric acid.. The mass spectrometer used is a Vacuums Generator Isomass 54R solid source with aDaly collector to improve the quality of measurement of the low intensity 204PB signals. Error in U-Pbages were obtained by individually propagating all the calibration and measurement uncertainties throughthe entire age calculation and summing the individual contributions to the total variance (Roddick, 1987).The decay constants used for the age calculation are those recommended by TUGS Subcomission onGeochronology (Steiger and Jager, 1977). Concordia intercepts are based on a York (1969) regressionmodel and the Ludwig (1980) error logarithm. Errors reported for the raw U-Pb data are one sigma; thosefor final ages and those shown on concordia plots for two sigma (95% confidence limits).137Galena Pb AnalysesSampling ProcedureTwo samples of galena were collected from skarn mineralization in the northern and central pitat the Nickel Plate mine. Clean cubes of galena were handpicked under a binocular microscope, rinsed inultrapure water to minimize contamination from other lead bearing sources and placed in sinai! beaker fordissolutiolLAnalytical MethodsAnalysis of galena was completed at The University of British Columbia by A. Pickering and J.Gabites using mass spectrometiy and the silica gel-phosphoric acid method described by Cameron eta!.(1969). Galena is dissolved in high purity 2-normal hydrochloric acid and evaporated to diyness to obtainlead chloride. The lead chloride etystals are washed several times in 4-normal hydrochloric acid and thenredissolved in ultrapure water. One microgram of lead from the lead chloride solution is combined withphosphoric acid and silica gel and loaded onto a clean, single, rhenium filament. The loaded filament isrun in a Vacuum Generators Ltd. Isomass 54R solid source mass spectrometer interfaced with a HewlettPackard-85 computer. Ratios of the various lead isotopes, i.e. 207Pb/6,208Pb/6 andare measured at least five times for each data blocL A minimum of six data blocks aretaken for each sample run. At the end of the run, the raw data is converted to ratios of: 206P’j/4Pb207Pb/4,208Pb/4,207PB/6band208Pb/. Reported results represent the normalizedmeans of the calculated ratios. Within-nm precision is usually better than 0.01 percent standard deviation.Absolute variation in duplicate analyses is generally less than 0.10 percent. Errors associated with massspectrometly of lead isotopes (nm instability, 204Pb error and fractionation error) are monitored byrepeated measurement of standards and duplicate analysis. For a complete description of these errors andof standards used the reader is referred to Godwin eta!. (1988).TableB.1:U-Pbanalysesof zirconfractionsfromintrusiveandtuffaceousrocks intheHedleyarea,south-central BritishColumbia.SamplelocationsareonFigure3.1. U-Pbanalysisof eachrockunitareplottedonconcordiadiagrams(Fig.3.10).AnalysesarebyP.Vander Heyden,D.MurphyandJ.Gabites(writtencommunications,1989to1990),GeochronometryLaboratory, TheUniversityof BritishColumbia,Vancouver, B.C.Fraction’Concentration2PbIsotopeAbundanceMeasuredAtomicRatios(datesMa)4(MagneticWtUPb207Pb20Pb204Pb206Pb/4b206Pb/38U207Pb/35U207Pb/6bproperties)(mg)(ppm)(ppm)Date±1SDDate±1 SDDate±1 SD(MeshSize)206Pb=100PicogramsofblankPb3SKWELPEKENFORMATION(HD-271;Z1,Fig.3.1;unit13;5461080N,707800E):NM2A/1°0.42295.15.56899.98610.025315380.02227±0.000220.1596±0.00080.05198±0.00051-100+200m50142.0±1.4150.3±0.7284.3±22ABRM1.5A13°0.43729.56.133013.5910.078210550.02445±0.000060.1680+0.00070.04984±0.00012-200+325m37155.7±0.4157.7±0.6187.5±5.6NM2A/1°0.22838.17.69616. 17890.18422600.02593±0.000060.1783±0.00210.04989±0.00056-100+200m200165.0±0.4166.6±1.8189.9±26.5ABRRHYOLITEPORPHYRY(HD-272;Z2,Fig.3.1;unit12;5463220N,705720E):NM2A/1°1.6104226.36.736114.02280.10758650.02381±0.000120.1694±0.00090.05159±0.000 10-100+200m200151.7±0.8158.9±0.8267.9±4.4ABR 1.M, NM=magneticandnonmagneticfractionsseparatedonFranzisodynamicseparator at indicatedamperageandangleof sidetilt.ABR=abradedfraction.2.UandPbconcentrationsarccorrectedforblankPb.3.Isotopiccompositionofvariable blankis206:207:208:204=17.75:15.50:37.30:1.00. CommonPbassumedtobeStaceyandKramers(1975) modelPbof 190+80Maage.4.IUGSconventional decayconstants(SteigerandJager,1977) are:238U=1.55125*1040a,235U9.8485*1040a,238U/5137.88atomratio.0TableB. 1:U-Pbanalysesof zirconfractionsfromintnisiveandtuffaceousrocksintheHedleyarea,south-centralBritishColumbia(continued)...Fraction’Concentration2PbIsotopeAbundanceMeasuredAtomicRatios(datesMa)4(MagneticWtUPb207Pb208Pb204Pb206Pb/4b206Pb/38U207Pb/35U207Pb/6bproperties)(mg)(ppm)(ppm)Date±1SDDate±1 SDDate±ISD(MeshSize)206Py10PicogramsofblankPb3RHYOLITEPORPHYRY(ND-272;Z2,Fig.3.1;unit12; 5463220N,705720E):M2AJ1°2.1125131.35.902512.5160.068914170.02425±0.00015-20080154.5±0.9ABR0.02523±0.00013160.6±0.60.02717±0.00030172.8±1.9N,715050E):0.02060±0.00008131.4±0.50.02238±0.00006142.7±0.40.02303±0.0002080146.8±1.30.02554±0.00022162.6±1.4M2AJ1°2.1156744.37.913717.33520.2006484-200m200NM2AJ1°3.9109731.76.654614.33020.1131854-100+200m200CAHILLCREEKPLUTON(HD-80;Z3,Fig.3.1;unit10;5469140M2AJ3°3.278518.48.014719.17200.2051478-200+325m120NM2A/1°3.251311.65.291611.87880.01934056-100+200m120NM2AI1°2.554612.75.106612.23320.01285871-200+325mABRNM2AJ1°4.840410.55.141412.45440.01325018-100+200200ABR0.1641±0.00110.04907±0.00012154.2±1.0151.0±5.80.1727±0.00120.04965±0.00020161.8±1.0178.7±9.20.1870±0.00210.04992±0.00026174.1±1.8191.3±12.00.1420±0.00180.05002±0.00056134.9±1.6195.7±26.40.1546±0.00450.05008±0.00138145.9±3.9198.8±650.1562±0.00150.04919±0.00016147.4±1.3156.7±7.80.1742±0.00130.04947±0.00017163.1±1.4170.2±8.0TableB.1:U-PbanalysesofzirconfractionsfromintrusiveandtuffaceousrocksintheHedleyarea,south-centralBritishColumbia(continued)...Fraction1Concentration2PbIsotopeAbundanceMeasuredAtomicRatios(datesMa)4(MagneticWtUPb207Pb208Pb204Pb206Pb/4b206Pb/38U207Pb/35Uproperties)(mg)(ppm)(ppm)Date±1SDDate±1SDDate±1SD(MeshSize)206P’.1yPicograinsofblankPb3MOUNTRIORDANSTOCK(HD.406;Z4,Fig.3.1;unit9;54761119N,288478E):NM2AJ1°0.91916.56.587212.0630.081710780.03274±0.000090.2435±0.0010.05392±0.00011+200m37207.7±0.6221.2±0.8367.8±4.7ABRM1.5A/3°0.42508.57.678014.7350.17425170.03127±0.000080.2209±0.00110.05123±0.00018-200m37198.5±0.5202.6±0.9251.1±7.9ABRBANBURYSTOCK(HD-273;Z5;Fig.3.1;unit7;5470950N,708310E):M2A/l°1.0152439.05.984016.61060.056815210.02387±0.000040.1695±0.00030.05150±0.00004-200m200152.1±0.2159.0±0.3263.4±1.6M2A/1°0.4112431.75.664115.8890.026231730.02678±0.000170.1937±0.00080.05262±0.00012-20037170.4±1.0180.9±..2.0320.5±15ABRNM2A/1°2.092627.05.216714.17100.011057740.02833±0.000090.1975±0.00070.05056±0.00007-200m200180.1±0.6183.0±0.6220.6±3.2NM2A/1°0.4117434.95.210615.77110.011427940.02847±0.000060.1980±0,00050.05043±0.00006-100+200m200181.0±0.4183.4±0.4214.9±2.9TableB.1:U-PbanalysesofzirconfractionsfromintrusiveandtuffaceousrocksintheHedleyarea,south-central BritishColumbia(continued)....Fraction1Concentration2PbIsotopeAbundanceMeasuredAtomicRatios (datesMa)4gneticWtup,207p’,,208pi32O4pi206PbI4b206Pb/38U207Pb/35U207Pb/6bproperties)(mg)(ppm)(ppm)Date±1SDDate±1SDDate±1SD(MeshSize)206Pb=100PicogranisofblankPb3STEMWNDERSTOCK(HD-81; Z6,Fig.3.1;unit7;5472310N,711500E):NM2A/3°2.044012.65.475814.39830.020435150.02758±0.000070.1969±0.00080.05177±0.00016-100+200m120175.4±0.5182.5±0.7275.3±6.9NM2AI.50.489327.66.625119.90950.10727210.02778±0.000090.1935±0.00080.05051±0.00012-200+325m200176.6±0.6179.6±0.7218.6±5.4M2A/3°1.687926.15.748617.40020.042620990.02782±0.000 100.1965±0.00100.05124±0.00018-200+325m120176.9±0.6182.2±0.6251.5+8.2M2A/0.5°0.442113.46.642618.13660.10356000.02898±0.000080.2047±0.00170.05124±0.00039-100+200m200184.2÷0.5189.1+1.5251.7+17.5TableB.2:OtherK-Ar(biotite, hornblendeandamphibole)andU-Pb(zircon)analysesofintrusiverocksintheHedleyarea,south-central BritishColumbia.DataareincorporatedwithdatafromTableB.IinFigure3.18.SampleNo.MapNo.1UTMCoordinatesUnitMineralDateanderrorReferenceNorthingEasting(Ma)2Hedleyintrusions:21aA154717507146257amphibole175.2±5.2RoddicketaL,19722lbA254717507146257amphibole180.7±5.8Roddicketal.,197222A354718507144507amphibole193.0±6.0Rodd.icketah,197224A454718257141007amphibole195.0±6.0RoddicketaL,197226aA554719007152257amphibole175.0±5.4Roddicketah,197226bA654719007152257amphibole184.0±7.4Roddicketa!.,197228A754731757125257amphibole187.8±5.8Roddicketal.,1972Bromleybatholith:8H154735007065258hornblende186.1±5.6Roddicketah,19729B154745007085758biotite180.9±5.4Roddicketal.,19729H254745007085758hornblende188.1±5.8Roddickeral.,19728-2Z754738507053008zircon193.0±1.0ParrishandMonger,19918-2H354738507053008hornblende185.7±2.8Monger,19898-2B254738507053008biotite173.4±4.7Monger,1989CahillCreekpluton:1B3546960071382511biotite158.4±4.8Roddicketah,1972IaB4546960071382511biotite153.4±4.6Roddicketah,1972lbB5546960071382511biotite154.4±4.6RoddicketaL,19721.MapnumberisplottedonFigure3.1.2.Allanalyseshavebeencorrectedtomoderndayconstants.TableB.2:OtherK-Ar(biotite,homblendeandamphibole)andU-Pb(zircon)analysesof intrusiverocksintheHedleyarea,south-cent.ralBritishColumbia(continued)....SampleNo.MapNo.’UTMCoordinatesUnitMineralDateanderrorReferenceNorthingEasting(Ma)2CahillCreekpluton:2H4546945071430011hornblende159.9±2.9Roddicketat.,19723B6546962571480011biotite160.9±4.8Roddicketat.,19724B7547020071582511biotite160.4±4.8Roddicketat.,19725B8547207571345011biotite161.3±3.Roddicketat.,19725H5547207571345011hornblende162.8±5.0Roddicketat.,19726B9547002571515011biotite158.6±4.8Roddicketat.,19727H6546875070915011hornblende174.5±5.2Roddicketa!.,197210B10546800070982511biotite155.9±4.8Roddicketat.,1972LookoutRidgepluton:13B11547602571257512biotite164.5±4.8Roddicketa!.,1972TableB.3:Galenaleadisotopedata’fortheNickel PlategoldskarnandtheCopperMountaincopper-goldporphyrydeposit,south-centralBritishColumbia.DataareplottedonFigure3.16.Sample206PbI204Pb207Pb/204Pb208Pb/204Pb207Pb/206Pb*100208Pb/206Pb*10NickelPlate(Li)230302-00118.75915.63138.44183.32920.49330302-00218.72415.60538.35483.34320.48630302-00318.73115.60738.36883.32120.48430302-AVG318.73815.61438.38883.33120.488CopperMountain30445-00118.67415.57138.18483.38320.44930445-00218.67815.56438.18383.32820.44430445-00318.66315.56438.16183.39520.44830445-AVG318.67215.56638.17683.36920.447MEAN±STDDEV418.70±0.0315.59±0.0038.28±0.1183.35+0.0320.47+0.021.SampleswereanalyzedbyAnnePickeringandJanetGabites,GeochronometryLaboratory,Department ofGeological Sciences,TheUniversityofBritishColumbia,Vancouver, B.C.,Canada.AvacuumGenerators Ltd. Isomass54Rsolidsource,singlefilament(silicagelmethod),massspectrometerwasused.Errorsattwosigmaarelessthan0.0 1%.2.SamplenumberLi is plottedonFigure3.1.3.AVG3istheaverageof thethreeanalysestabulatedimmediatelyabove.4.MEAN±STDDEVisthemeanandstandarddeviationof the6analysesabove.APPENDIX C: Lithogeochemical analyses from the Jiedley area, south-central BritishColumbia.Appendix C contains information on sampling procedure, analytical method, and tables of majorand minor element analyses with their calculated CIPW normative mineralogy for intrusive (units 7,9and 10) and extrusive (units 6, 13a and 13b) units in the Hedley area (Ray and Dawson, 1994; TablesC.1.and C.2), and from phyric and aphyric Hedley intrusions (unit 7) in the French mine area (this study;Tables C.3 and C.4), south-central British Columbia. Sample locations are on Figures 3.1 and 4.6,respectively.145146Sampling ProcedureOne to two kg samples were collected from unaltered intrusive and extrusive rocks in the Hedleyarea (Tables C. 1 and C.2), and from phyric and aphyric Hedley intrusions in the French mine area (TablesC.3 and C.4). Samples in Tables C. 1 and C.2 were prepared at the B.C. Energy, Mines and PetroleumResources Laboratory where they were crushed to chip size in a jaw crusher, and split and pulverized in atungsten carbide ring mill.Samples in Tables C.3 and C.4 were prepared at The University of British Columbia where theywere crushed to chip size in a jaw crusher, pulverized in a tungsten carbide ring mill for two minutes andreduced to a 100-200 gm sample by repetitive splitting. The jaw crusher was cleaned with a wire brushand compressed air, the ring mill was cleaned with water and compressed air, and the splitter andsampling trays were cleaned with paper towels and compressed air between each sample run.Analytical MethodsMajor oxides in Table C. 1 were determined by fused disk X-ray fluorescence (XRF) at B.C.Energy, Mines and Petroleum Resources Laboratory. Loss on ignition (LOT) was calculated after heatingpredried samples to 1050°C for four hours. Precision for major elements averages 5% relative error.Trace elements in Table C.2 were determined by fused disk XRF (Co, Cr, Hg, Sb, Ba, Sr, Te, Rb,Y, Zr, Nb, Ta, U and Th), flame atomic spectroscopy absorption (ASS; Ag, Cu, Pb, Zn, Ni, Mo, As andBi) and fire assay - atomic absorption spectroscopy (AAS) finish (Au) at the B.C. Energy, Mines andPetroleum Resources Laboratory. Precision for trace elements averages 5% relative error.Major oxides in Table C.3 were determined by fused disk XRF at the Cominco Laboratory. LOlwas calculated after heating predried samples to 1050°C for four hours.Trace elements in Table C.4 were determined by fused disk XRF at the Cotninco Laboratory (Rb,Sr, Nb, Zr, Y and Ba) and the B.C. Energy, Mines and Petroleum Resources Laboratory (Cr, Ti, V. La,Ce), by atomic absorption spectrometry at the B.C. Energy, Mines and Petroleum Resources Laboratory(Ni, Co, Cu, Pb, Zn, Mo and As), and by induced coupled plasma (ICP) at the Acme Labs Ltd. (Bi, Te).147Table C.l: Major element analyses and C1PW normative mineralogy of volcanic and intrusive rocks from theHedley area, south-central British Columbia. Major element values are in weight percent Analyses were by fuseddisk XRF completed at the B.C. Ministay of Energy, Mines and Petroleum Resources Laboratoiy, Victoria, B.C.Loss on ignition (LOl) was calculated after heating predried samples to 10500 C for four hours. Fe203 isexpressed as total iron. Symbols <H, tN and “*“ denote below detection limit, not analysed and lab duplicate,respectively.FIELD NO. 521 522 523 525 526 50 52 60 60MAP NO. 1 Wi W2 W3 W4 W5 W6 W7 W8 W8LAB NO. 34188 34175 34176 34178 34179 30825 30826 30827 30843NORTHING 5454200 5470132 5469954 5469562 5469332 5469906 5469964 5472322 5472322EASTING 700385 706060 705870 704891 704753 707907 707558 711537 7115376 6 6 6 6 7 7 7 7Si02 48.27 45.56 50.29 55.89 49.55 54.21 54.29 56.81 57.24Ti02 0.72 0.79 0.77 0.66 0.94 0.79 0.83 0.60 0.62A1203 15.51 16.62 17.86 15.38 15.72 19.20 19.53 17.50 18.01Fe203m 10.94 10.11 9.00 7.04 10.34 9.25 8.11 7.03 7.13MnO 0.19 0.21 0.18 0.16 0.19 0.17 0.15 0.12 0.13MgO 8.51 4.67 3.85 3.58 5.57 4.49 3.24 3.81 3.86CaO 11.58 10.91 8.00 7.04 6.86 9.90 9.16 7.98 8.04Na20 2.04 2.80 4.16 3.91 3.51 2.69 3.12 3.03 3.04K20 0.53 2.05 1.16 1.52 2.21 0.83 0.93 1.64 1.650.14 0.26 0.16 0.30 0.27 0.23 0.26 0.15 0.15LOl 1.20 5.55 3.81 4.52 4.47 1.68 1.25 0.97 0.96SUM 99.63 99.53 99.24 100.00 99.63 103.44 100.87 99.64 100.83CIPW Normative Minerals3Q 0.00 0.00 0.00 8.85 0.00 10.08 10.47 12.75 12.50C 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Z 0.01 0.01 0.01 0.02 0.01 0.01 0.01 0.01 0.01OR 3.20 12.98 7.23 9.45 13.82 4.84 5.53 9.86 9.80AB 17.61 17.14 37.11 34.82 31.43 22.43 26.56 26.04 25.81AN 32.24 28.64 28.09 20.98 21.82 37.31 36.77 29.76 30.73NE 0.00 4.47 0.00 0.00 0.00 0.00 0.00 0.00 0.00DI 21.65 22.42 10.32 11.13 9.99 7.48 5.64 7.36 6.47HY 14.79 0.00 7.73 8.96 8.71 7.55 5.50 6.23 6.65OL 3.10 6.59 2.77 0.00 6.11 0.00 0.00 0.00 0.00MT 5.66 5.50 4.81 3.76 5.55 6.22 5.17 4.83 4.83CM 0.06 0.01 0.00 0.01 0.03 0.00 0.00 0.01 0.01Hlvf 0.00 0.00 0.00 0.00 0.00 2.09 2.15 L67 1.68IL 1.39 1.61 1.54 1.32 1.89 1.48 1.59 1.16 1.18A? 0.34 0.66 0.40 0.75 0.68 0.54 0.62 0.36 0.36SUM 100.06 100.02 100.02 100.04 100.04 100.02 100.02 100.03 100.031. Map number is plotted on Figure 3.1.2. Unit is identified in Table 3.1 and on Figure 1.1.3. CIPW Normative Minerals are Q-quartz, C- corundum, Z-zircon, OR-orthoclase, AB-albite, AN-anorthite, NEnepheline, DI-diopside, HY-hypersthene, OL-olivine, MT-magnetite, CM-chromite, HM-hematite, IL-ilimenite,AP-apatite.148Table C. 1: Major element analyses and CIPW normative mineralogy of volcanic and intrusive rocks from theHedley area, south-central British Columbia (continued)...FIELDNO. 62 64 65 66 67 68 69 70 71MAP NO.’ W9 W10 Wil W12 W13 W14 W15 W16 W17LAB NO. 30829 30831 30832 30833 30834 30835 30836 30837 30838NORTHING 5472771 5473042 5473143 5473242 5473346 5473415 5473809 5473907 5473410BASTING 711930 711770 711562 711419 711319 711212 711096 710966 711060UNiT2 7 7 7 7 7 7 7 7 7Si02 54.08 52.94 59.48 53.27 50.82 59.46 54.27 49.13 55.92Ti02 0.68 0.65 0.53 0.72 0.65 0.51 0.64 0.80 0.58A1203 18.35 19.89 17.86 19.02 20.24 17.99 19.33 20.18 18.41Fe203m 8.77 7.93 6.41 8.75 8.39 5.83 7.66 9.07 7.27MnO 0.17 0.15 0.11 0.16 0.17 0.13 0.17 0.16 0.14MgO 4.03 4.04 2.51 3.93 4.18 2.88 3.27 5.09 3.13CaO 9.25 10.15 6.66 9.12 10.30 7.24 9.19 11.46 8.14Na20 2.91 3.40 3.28 3.10 2.90 3.72 3.20 2.55 3.22K20 1.11 1.24 2.00 1.35 0.75 2.01 1.55 1.17 1.660.16 0.19 0.14 0.17 0.20 0.15 0.20 0.18 0.17LOl 1.03 1.10 1.00 1.32 1.24 0.87 1.12 1.51 1.26SUM 100.54 101.68 99.98 100.91 99.84 100.79 100.60 101.30 99.90CIPW Normative Minerals3Q 9.99 4.13 16.18 7.38 5.54 12.60 8.04 1.53 11.18C 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Z 0.01 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01OR 6.62 7.31 11.98 8.04 4.51 11.92 9.24 6.96 9.9824.81 28.67 28.09 26.41 24.95 31.56 27.28 21.68 27.68AN 33.99 35.23 28.45 34.23 40.67 26.52 34.06 40.36 31.37NE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00DI 8.72 10.68 3.17 7.95 7.75 6.62 8.22 12.14 6.64HY 6.07 5.08 4.86 6.17 6.99 4.12 4.39 7.11 4.84OL 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00MT 6.26 5.48 4.45 6.09 6.07 4.03 5.40 6.11 5.17CM 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01HM 1.87 1.75 1.47 1.97 1.78 1.31 1.68 2.16 1.60IL 1.30 1.23 1.02 1.38 1.25 0.97 1.22 1.53 1.12AP 0.38 0.45 0.34 0.41 0.48 0.36 0.48 0.43 0.41SUM 100.02 100.02 100.02 100.02 100.02 100.02 100.02 100.03 100.03149Table C. 1: Major element analyses and CIPW normative mineralogy of volcanic and intrusive rocks from theHedley area, south-central British Columbia (continued)...FIELD NO. 72 73 73* 156 157 158 159 161 162MAP NO.1 W18 W19 W19 W20 W21 W22 W23 W24 W25LAB NO. 30839 30840 30844 31849 31850 31851 31852 31854 31855NORTHING 5473200 5473215 5473215 5470521 5470666 5471625 5472167 5471068 5471111EAST]NG 710980 711065 711537 712967 712905 712191 712424 714497 713668IJMT2 7 7 7 7 7 7 7 7 7Si02 54.85 57.68 55.38 54.83 55.56 53.33 55.61 54.12 53.36TiC)2 0.65 0.67 0.66 0.67 0.66 0.56 0.61 0.65 0.68A1203 18.72 18.60 18.61 18.81 18.71 19.24 18.38 18.22 18.57Fe2O3m 8.08 7.91 8.05 7.98 7.53 8.19 7.35 8.32 7.31MnO 0.15 0.15 0.15 0.14 0.16 0.14 0.12 0.14 0.12MgO 3.54 3.10 3.06 4.83 4.16 4.45 3.69 4.10 4.23CaO 8.73 8.23 8.00 8.00 7.13 9.47 8.12 8.32 8.32Na2O 3.06 3.22 3.21 3.20 3.28 2.77 2.91 2.72 2.77K20 1.65 1.80 1.78 0.64 1.37 1.17 100 1.01 1.100.18 0.21 0.21 0.14 0.17 0.17 0.15 0.16 0.16LOI 1.17 1.26 1.15 1.42 1.82 1.36 1.35 1.11 2.69SUM 100.78 102.83 100.26 100.66 100.55 100.85 99.29 98.87 99.31CIPW Normative Minerals3Q 9.40 12.05 10.45 10.72 10.82 8.35 13.80 12.48 10.87C 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00z 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01OR 9.82 10.51 10.65 3.83 8.23 6.98 6.06 6.13 6.76AB 26.06 26.89 27.47 27.35 28.17 23.62 25.20 23.60 24.31AN 32.68 30.58 31.47 35.43 32.77 36.89 34.93 35.41 36.29NE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00DI 7.57 6.51 5.67 2.91 1.56 7.27 4.12 4.56 4.24HY 5.36 4.60 5.08 0.80 9.79 7.80 7.50 8.36 8.96OL 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00MT 5.67 5.36 5.64 5.50 5.23 6.00 5.13 5.95 4.95CM 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 0.01HM 1.78 1.77 1.81 1.85 1.74 1.64 1.73 1.87 1.89IL 1.24 1.26 1.27 1.28 1.27 1.07 1.19 1.27 1.34AP 0.43 0.49 0.50 0.33 0.41 0.41 0.36 0.39 0.39SUM 100.02 100.02 100.02 100.02 100.03 100.02 100.02 100.02 100.02150Table C. 1: Major element analyses and CIPW normative mineralogy ofvolcanic and intrusive rocks from theHediley area, south-central British Columbia (continued)...FIELD NO. 163 164 218 334 767 381 406 77 78MAP NO.1 W26 W27 W28 W29 W30 W31 W32 W33 W34LAB NO. 31856 31857 31858 33914 34198 34197 33916 30845 30846NORTHING 5471489 5472219 5471860 5473601 5474500 5475550 5476119 5468971 5469056BASTING 713725 712174 715260 282307 711050 287800 288478 715093 715086jNrr2 7 7 7 7 9 9 10 10Si02 54.13 56.38 54.31 54.25 53.68 64.02 63.27 61.29 61.13Ti02 0.62 0.58 0.61 0.65 1.04 0.48 0.48 0.66 0.65203 17.55 18.37 18.29 17.92 16.72 16.60 16.88 18.34 18.17Fe2O3m 6.64 6.29 6.01 7.59 10.11 5.53 5.51 5.46 5.34MnO 0.09 0.10 0.07 0.16 0.17 0.10 0.09 0.11 0.12MgO 3.99 3.41 3.83 3.71 4.84 2.15 2.23 1.83 1.84CaO 6.48 7.10 7.45 7.83 8.00 5.25 5.31 4.81 4.86Na20 4.79 4.06 3.34 3.87 3.26 3.13 3.53 4.39 4.39K20 2.13 1.01 2.08 2.54 1.36 2.09 1.56 2.44 2.48‘2OS 0.16 0.17 0.18 0.19 0.20 0.11 0.12 0.13 0.13LOl 1.75 1.28 2.43 0.62 0.56 0.72 0.75 0.99 0.79SUM 98.33 9875 98.60 99.33 99.94 100.18 99.73 100.45 99.90CIPW Normative Minerals3Q 1.14 10.48 7.56 3.88 8.26 22.53 21.32 12.59 12.37C 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.04 0.00Z 0.01 0.01 0.01 0.00 0.00 0.00 0.00 0.04 0.04OR 13.08 6.15 12.83 15.17 8.11 12.46 9.35 14.57 14.86AB 42.05 35.31 29.44 33.09 27.84 26.72 30.28 37.47 37.60AN 20.85 29.73 29.97 24.28 27.23 25.30 25.91 23.22 22.82NE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00DI 8.89 4.16 5.69 8.27 8.96 0.21 0.00 0.00 0.59HY 6.19 6.80 7.30 5.51 8.01 8.38 8.69 7.34 7.06OL 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00MT 4.43 4.23 3.84 5.30 6.39 3.24 3.24 3.19 3.13CM 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00HM 1.77 1.61 1.74 1.72 2.73 0.00 0.00 0.00 0.00IL 1.22 1.13 1.21 1.25 1.99 0.92 0.92 1.26 1.25Al’ 0.39 0.41 0.44 1.58 0.48 0.26 0.29 0.31 0.31SUM 100.03 100.02 100.03 100.03 100.01 100.01 100.01 100.04 100.04151Table C. 1: Major element analyses and CIPW normative mineralogy of volcanic and intrusive rocks from theHedley area, south-central British Columbia (continued)...FIELD NO. 79 80 717 514.15 514.6 151 152 171 172MAP NO.1 W35 W36 W37 W38 W39 W40 W41 W42 W43LAB NO. 30847 30848 34181 35229 35234 31860 31861 31863 31864NORTHING 5469056 5469196 5470427 5469300 5469300 5461980 5461900 5461155 5461223EASTING 715086 715086 715746 717700 717700 708800 708770 707726 707744UNiT2 10 10 10 10 10 13a 13a 13a 13aSi02 60.00 60.54 64.72 63.82 63.01 62.51 62.45 62.77 65.21Ti02 0.71 0.66 0.50 0.50 0.53 0.51 0.49 0.54 0.48A1203 18.12 18.67 16.33 18.06 17.80 18.14 19.15 18.61 18.17Fe2O3m 5.70 5.23 4.80 4.06 4.32 5.33 3.60 5.06 5.30MnO 0.13 0.11 0.11 0.08 0.09 0.10 0.12 0.11 0.11MgO 2.09 1.80 1.56 1.08 1.25 0.69 0.55 0.93 0.89CaO 5.24 4.96 3.95 3.85 4.01 3.93 3.88 4.71 4.17Na20 4.26 4.25 3.80 4.32 4.35 3.73 4.72 3.73 3.651(20 2.43 2.59 2.87 2.89 2.89 1.39 1.59 1.49 1.490.17 0.10 0.13 0.12 0.13 0.16 0.17 0.15—LOl 1.08 0.80 1.35 1.31 1.53 1.62 1.06 0.98 1.03SUM 99.93 99.71 100.12 100.09 99.91 98.11 97.78 99.08 100.50CIPW Normative Minerals3Q 11.28 11.85 20.36 17.45 15.88 26.18 20.13 23.61 27.29C 0.00 0.10 0.10 1.13 0.55 3.89 3.13 2.72 3.35Z 0.04 0.04 0.00 0.00 0.00 0.02 0.03 0.02 0.02OR 14.60 15.55 17.22 17.34 17.41 8.56 9.75 9.02 8.88AB 36.59 36.47 32.65 37.09 37.51 32.82 41.38 32.27 31.10AN 23.49 24.30 19.04 18.59 19.41 19.19 18.80 22.89 19.85NE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00DI 1.44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00HY 7.46 7.15 6.54 4.77 5.36 4.77 3.28 5.08 5.17OL 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00MT 3.36 3.08 2.83 2.39 2.55 3.21 2.16 3.00 3.09CM 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00HM 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00IL 1.37 1.27 0.96 0.96 1.03 1.01 0.96 1.05 0.92AP 0.41 0.24 0.31 0.29 0.31 0.39 0.42 0.36 0.36SUM 100.05 100.04 100.01 100.01 100.01 100.03 100.03 100.03 100.03152Table C. 1: Major element analyses and CIPW normative mineralogy of volcanic and intrusive rocks from theHedley area, south-central British Columbia (continued)....FIELD NO. 173 309 527 528 529 530 531 532MAP NO.1 W44 W45 W46 W47 W48 W49 W50 W51LAB NO. 31865 32194 34189 34190 34191 34192 34193 34194NORTHING 5461355 5475072 5460444 5460808 5460913 5459828 5462426 5462517BASTING 707602 716367 703502 703772 703834 703409 706268 706356T.TfI2 13a 13a 13b 13b 13b 13b 13b 13bSi02 64.99 62.08 61.11 60.67 59.03 58.56 60.69 60.80TiO2 0.49 0.47 0.65 0.63 0.65 0.75 0.61 0.58A1203 18.13 17.25 17.16 16.00 16.48 17.18 17.18 16.83Fe2O3m 4.28 5.13 6.69 6.71 6.95 7.73 6.93 6.45MnO 0.13 0.14 0.12 0.12 0.19 0.17 0.17 0.19MgO 0.94 1.44 1.46 2.32 2.40 2.58 2.38 2.37CaO 3.95 5.74 5.82 5.18 5.58 6.39 5.65 5.93Na20 3.79 4.02 3.21 3.15 3.12 3.25 3.45 3.531(20 1.57 1.47 1.78 1.96 2.02 1.94 1.90 1.920.15 0.12 0.17 0.16 0.17 0.18 0.16 0.16LOl 1.52 1.16 1.68 2.04 2.47 0.75 1.04 1.26SUM 99.94 99.02 99.85 98.94 99.06 99.48 100.16 100.02C]PW Normative Minerals3Q 26.94 18.75 20.03 19.60 16.92 13.95 16.46 16.22C 3.44 0.00 0.00 0.00 0.00 0.00 0.00 0.00Z 0.02 0.02 0.02 0.02 0.03 0.02 0.02 0.02OR 9.47 8.91 10.76 12.01 12.42 11.67 11.38 11.54AB 32.67 34.87 27.79 27.63 27.46 27.99 29.58 30.37AN 18.97 25.30 27.79 24.60 26.01 27.04 26.13 24.82NE 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00DI 0.00 2.53 0.51 0.78 1.34 3.31 1.00 3.30HY 4.69 5.38 7.96 10.22 10.48 10.15 10.32 8.91OL 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00MT 2.53 3.05 3.47 3.53 3.67 3.99 3.56 3.33CM 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01NM 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00IL 0.95 0.91 1.26 1.24 1.28 1.45 1.17 1.12AP 0.36 0.29 0.41 0.39 0.42 0.43 0.38 0.39SUM 100.03 100.02 100.03 100.03 100.03 100.02 100.03 100.03153Table C.2: Trace element analyses of volcanic and intrusive rocks from the Hedley area, south-central BritishColumbia. Analyses were completed at the B.C. Miiustiy of Energy, Mines, and Petroleum Resources Laboratoiy,Victoria, B.C. Values are in parts per million. Symbols M<H, U_ and “‘i’” denote below detection limit, not analysedand lab duplicate, respectively.FIELD NO. 521 522 523 525 526 50 52 60 60*MAP NO.1 Wi W2 W3 W4 W5 W6 W7 W8 W8LAB NO. 34188 34175 34176 34178 34179 30825 30826 30827 30843NORTHING 5454200 5470132 5469954 5469562 5469332 5469906 5469964 5472322 5472322EAST.[NG 700385 706060 705870 704891 704753 707907 707558 711537 711537liMIT2 6 6 6 6 6 6 7 7 7Au———— <5 21 6 6 49Ag-- —— 400 <300 <300 <300 <300Cu 120 69 104 103 12 7 28 25 30Pb 23 7 5 5 <3 4 4 5 3Zn 90 90 90 103 93 82 59 58 71Co 32 23 22 33 34 30 36 37 37Ni 14 2 23 38 10 7 16 12 4Mo <8 <8 <8 <8 <3 <3 <3 <3 <3Cr———— <3 <25 58 64 <25Hg———— <25 <25 25 40 <25As 7.4 6.2 4.7 5.9 <10.0 <10.0 <10.0 <10.0 <10.0Sb 0.6 1.0 0.8 0.8 <10.0 <10.0 <10.0 <10.0 <10.0Ba 1067 715 1391 2136 940 962 1140 1160 862Sr—-- —— 575 614 450 438 546Bi <3 <3 <3 <3 <3 <3 <3 <3 <3TeRb—--—— 5 3 35 41 22Y 19 19 26 23 12 14 13 10 12Zr 46 48 80 64 48 55 61 64 52Nb 1 1 7 1 <3 <3 <3 <3 <3Ta— ——— <4 <4 <4 — <4U—— —— <2 <2 <2 <2 <2Th— ——— 29 23 30 24 251. Map number is plotted on Figure 3.1.2. Unit is identified in Table 3.1 and on Figure 1.1.154Table C.2: Trace element analyses of volcanic and intrusive rocks from the Hedley area, south-central BritishColumbia (continued)...FJELDNO. 62 64 65 66 67 68 69 70 71MAP NO.’ W9 W10 Wil W12 W13 W14 W15 W16 W17LAB NO. 30829 30831 30832 30833 30834 30835 30836 30837 30838NORTH1NG 5472771 5473042 5473143 5473242 5473346 5473415 5473809 5473907 5473410EASTING 711930 711770 711562 711419 711319 711212 711096 710966 711060UNIT2 7 7 7 7 7 7 7 7 7Au 49 5 22 9 16 15 19 11 6Ag <300 <300 <300 <300 <300 <300 <300 <300 <300Cu 30 7 5 9 15 8 28 60 8Pb 3 3 6 9 4 3 3 3 3Zn 71 59 50 74 62 42 57 60 51Co 37 35 32 32 30 29 30 31 31Ni 4 4 2 4 7 4 3 6 4Mo <3 <3 <3 <3 <3 <3 <3 <3 <3Cr <25 <25 <25 <25 <25 <25 <25 42 32Hg <25 <25 30 30 25 <25 25 50 30As <10 <10 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0 <10.0Sb <10 <10 <10.0 <10.0 <10.0 15.0 <10.0 <10.0 <10.0Ba 862 1307 1300 918 606 1154 1232 1088 <40Sr 546 810 333 494 653 380 520 466 708Bi <3 <3 <3 <3 <3 <3 <3 <3 <3Te— — — —— — — ——Rb 22 17 29 22 18 27 21 35 39Y 12 13 18 14 12 14 15 13 12Zr 52 47 81 53 40 68 50 44 66Nb <3 <3 <3 <3 <3 <3 <3 <3 <3Ta <4 <4 <4 <4 <4 <4 <4 <4 <4U <2 2 <2 <2 <2 <2 <2 1 <2Th 25 28 23 32 23 25 19 35 23155Table C.2: Trace element analyses of volcanic and intrusive rocks from the Hedley area, south-central BritishColumbia (continued)...FIELD NO. 72 73 73* 156 157 158 159 161 162MAP NO.’ W18 W19 W19 W20 W21 W22 W23 W24 W25LAB NO. 30839 30840 30844 31849 31850 31851 31852 31854 31855NORTHING 5473200 5473215 5473215 5470521 5470666 5471625 5472167 5471068 5471111BASTING 710980 711065 711065 712967 712905 712191 712424 714497 713668UNIT2 7 7 7 7 7 7 7 7 7Au 8 5 10 <30 <30 <30 <30 <30 <30Ag <300 <300 <300 <10 <10 <10 <10 <10 <10Cu 11 6 5 22 13 30 12 22 4.6Pb <3 5 7 23 9 13 12 14 13Zn 58 60 61 93 87 92 71 58 58Co 31 27 28 41 33 35 32 37 38Ni 3 3 2 25 9 13 8 11 11Mo <3 <3 <3 <3 <3 <3 <3 <3 5Cr <25 <25 <25 52 31 34 23 35 28Hg 25 25 40 <10 <10 28 10 23 13As <10.0 <10.0 <10.0 93.5 14.0 5.4 1.7 12.6 165.0Sb <10.0 <10.0 <10.0 2.5 1.1 <1.0 <1.0 1.0 1.1Ba 1014 1273 1200 756 811 854 652 653 1040Sr 519 484 494 841 667 636 654 679 819Bi <3 <3 <3 8 <5 <5 <5 <5 <5Te— —— <5 <5 <5 <5 <5 <5Rb 26 29 28 14 32 28 30 23 32Y 12 16 17 11 14 13 13 13 14Zr 56 70 70 53 59 51 67 60 59Nb <3 <3 <3 <3 <3 <3 <3 <3 <3Ta 1 <4 <4 <4 <4 <4 <4 <4 <4U <2 <2 2 <2 1 <2 1 <2 3Th 27 27 30 25 22 16 25 18 23156Table C.2: Trace element analyses of volcanic and intrusive rocks from the Hedley area, south-central BritishColumbia (continued)...FIELD NO. 163 164 218 334 767 381 406 77 78MAP NO.1 W26 W27 W28 W29 W30 W3 1 W32 W33 W34LAB NO. 31856 31857 31858 33914 34198 34197 33916 30845 30846NORTHING 5471489 5472219 5471860 5473601 5474500 5475550 5476119 5468971 5469056BASTING 713725 712174 715260 282307 711050 287800 288478 715093 7150867 7 7 7 7 9 9 10 10AuAgCuPbZnCoNiMoCrHgAsSbBaSrBiTeRbYZrNbTaUTh<5—<300-7 127 770 4424 112 8<10 <10— 177.5 2.71.1 <0.5— 1360<3 <323 20— 98— 7<20——20——10——61——— 33 295 48 4<2——— 10 4H——0.5——— 1297 1333— 432 421<10——— 57 61— 21 25— 209 217— <1 4191 <30 <30 20<10 <10 <10 <30016 18 73 1121 18 15 1057 48 76 6029 30 29 379 10 8 22<3 <3 <3 823 19 21 3521 12 11 <109.0 11.1 120.0 21.31.7 <1.0 2.0 1.21441 1022 1520 978920 837 676 67812 11 9 <5<5 <5 <5 <550 30 50 2214 12 14—59 63 59—<3 <3 <3—<4 <4————— <4 <4<2 <2 <2—--—— <2 <221 22 17———— 20 23AuAg———-Cu—— 6 10Pb—— 15 17Zn—— 65 46Co 30 26 8 7Ni 1 5 3 <3Mo—— 1 <10Cr 20 1 4—Hg——--As——— 7Sb—— 0.5 0.5Ba 1319 1390 1510—Sr 423 425 329--Bi--— <3 <5Te———--Rb 56 49 73--Y 24 22 22—Zr 218 216 172—Nb <1 1 6--Ta <4 <4 ——UThTable C.2: Trace element analyses of volcanic and intrusive rocks from the Hedley area, south-central BritishColumbia (continued)...157FIELD NO. 79 80 717 151 152 171 172MAP NO.’ W35 W36 W37 W38 W39 W40 W41 W42 W43LAB NO. 30847 30848 34181 35229 35234 31860 31861 31863 31864NORTHING 5469056 5469196 5470427 5469300 5469300 5461980 5461900 5461155 5461223EASTING 715086 715086 715746 717700 717700 708800 708770 707726 707744iNTl’2 10 10 10 10 10 13a 13a 13a 13a————— <30 <30 <30 <30-- <10 <10 <10 <108 18 12 14 99 16 16 13 1346 105 72 83 749 28 28 37 24<3 6 6 7 4<10 <3 <3 <3 <3— <10 <10 11 11— <10 <10 18 <105 3.2 1.7 1.7 1.02 <1.0 <1.0 <1.0 <1.0— 937 946 926 1028-- 632 596 532 543<5 <5 <5 <5 5-- <5 <5 <5 <5— 33 24 30 30— 19 23 22 17— 110 133 113 93— 1 <3 <3 <3— <4 <4 <4 6<2 <2 10 -- — <2 2 3 623 26 13— — 22 22 26 24158Table C.2: Trace element analyses of volcanic and intrusive rocks from the Hedley area, south-central BritishColumbia (continued)....FIELD NO. 173 309 527 528 529 530 531 532MAP NO.1 W44 W45 W46 W47 W48 W49 W50 W5 1LAB NO. 31865 32194 34189 34190 34191 34192 34193 34194NORTIIING 5461355 5475072 5460444 5460808 5460913 5459828 5462426 5462517EASTING 707602 716367 703502 703772 703834 703409 706268 706356uNIT2 13a 13a 13b 13b 13b 13b 13b 13bAu 35Ag <10— ——— ———Cu 6 — 26 36 38 20 12 25Pb 12 — 36 15 18 14 20 17Zn 73— 75 77 83 93 99 88Co 24 — 14 14 14 16 12 12Ni 6 — 2 2 <2 <2 5 12Mo <3 — <10 <10 <10 35 10 40Cr <10 — 18 12 16 6 19 28Hg 12— ——— ———As 2.5— 2.4 2.6 3.0 2.3 2.7 5.0Sb 1.0 — <0.5 0.6 0.6 0.6 0.7 1.1Ba 1211— ——— ———Sr 538——— ——— —Bi <5— 3 <3 4 4 3 <3Te <5—— ——— ——Rb 34 20 ——— ———Y 17 16 23 21 30 24 22 26Zr 106 96 121 116 123 105 105 113Nb <3 <3 4 1 15 2 5 12Ta <4 <4—— ————U 2 <2—— ————Th 20 21—— ————159Table C.3: Major element analyses and CIPW normative mineralogy of phyric and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia. Major element values are in weightpercent. Analyses were by fused disk XRF completed at the Cominco Laboratoty, Vancouver, B.C. Losson ignition (LOl) was calculated after heating predried samples to 1050°C for four hours. Fe203 isexpressed as total iron. Symbols”<”, “—“, “$“, “#“ and “*“ denote below detection limit, not analysed,field duplicate, field duplicate - chrome grinder and lab duplicate, respectively.FIELD NO. 2-2 12-1 12-2 12-5 12-15 12-15$ 124 124$MAP NO.1 Wi W2 W3 W4 W5 W5 W6 W6LAB NO. 40412 40413 40414 40425 40429 40424 40423 40420NORTHING 5467915 5467755 5467755 54.67740 5468025 5468025 5467690 5467690LASTING 716890 716435 716435 716350 716455 716455 716385 716385uNIT2 7 7 7 7 7 7 7 7ROCK Bin Bin Bin Bin Bin Bin hEm hEmTYPE3Si02 49.73 57.36 54.61 48.08 55.01 53.97 56.14 56.30Ti02 0.66 0.52 1.30 1.59 1.53 1.42 0.87 0.89A12O3 15.03 18.12 14.73 15.59 14.63 14.72 17.87 18.23Fe0(T) 7.05 5.75 10.75 11.08 10.29 10.50 9.14 9.22MnO 0.15 0.09 0.20 0.19 0.18 0.17 0.21 0.21MgO 4.27 3.31 6.88 6.94 6.52 6.97 3.98 4.21CaO 18.10 6.66 7.46 12.05 7.42 7.55 4.92 4.39Na20 2.72 4.54 2.96 2.83 3.21 3.27 5.69 5.63K20 0.50 2.42 0.44 0.57 0.67 0.57 0.57 0.770.29 0.15 0.18 0.16 0.19 0.17 0.19 0.21LOI 0.86 0.75 0.45 0.34 0.37 0.30 0.26 0.27SliM 99.36 99.67 99.96 99.42 100.02 99.61 99.84 100.33CIPW Nonnative Mineralogy4Q 0.00 2.17 6.89 0.00 6.44 4.35 0.36 0.52C 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.57Z 0.01 0.01 0.02 0.03 0.03 0.02 0.02 0.02OR 2.96 14.32 2.60 3.38 3.97 3.37 3.37 4.56AB 17.69 38.41 25.04 23.33 27.16 27.67 48.14 47.63AN 27.35 22.00 25.62 28.17 23.56 23.83 21.59 20.70NE 2.88 0.00 0.00 0.33 0.00 0.00 0.00 0.00DI 38.43 7.90 7.68 24.39 9.22 9.60 1.56 0.00WO 4.65 0.00 0.00 0.00 0.00 0.00 0.00 0.00HY 0.00 11.06 25.37 0.00 22.72 24.09 19.80 21.21OL 0.00 0.00 0.00 12.61 0.00 0.00 0.00 0.00MT 1.53 1.25 2.34 2.41 2.24 2.28 1.99 2.01CM 0.01 0.00 0.04 0.07 0.04 0.04 0.01 0.01IL 1.25 0.99 2.47 3.02 2.91 2.70 1.65 1.69Al’ 0.69 0.36 0.43 0.38 0.45 0.40 0.45 0.50CC 1.07 0.39 0.34 0.34 0.34 0.34 0.00 0.00SUM 98.54 98.86 98.86 98.46 99.08 98.71 98.94 99.411. Map number is plotted on Figure 4.6.2. Unit is identified in Table 3.1 and on Figure 4.1.3. Field classification of rock types are: Bin=aphyric basalt intrusion, bBm=hornblende phyric intrusion,qDi’=quartz diorite.4. CIPW Normative Minerals are: Q=quartz, Z=zircon, OR=orthoclase, AB’=albite, AN=’anorthite,NE=’nepheline, D1=diopside, WO=wollastonite, HY=hypersthene, OL”olivine, MT=magnetite, CM”cbiomite,IL=ilimenite, AP=apatite, CC=calcite.160Table C.3: Major element analysis and CJPW normative niineralogy of phyric and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia (continued)...FIELD NO. 12-11 12-16 89-36 89-37 89-37$ 2-3 2-3# 2-3#MAPNO.1 W7 W8 W9 W10 W10 Wil Wil WilLAB NO. 40428 40432 40435 40436 40442 40415 40418 40443NORTHING 5468325 5467765 5468000 5468000 5468000 5468068 5468068 5468068EASTING 716340 716395 716875 716875 716875 717320 717320 717320UNIT2 7 7 7 7 7 7 7 7ROCK hBin liBin liBin hBin hBin qDi qDi qDiTYPE3SiO2 54.22 55.59 49.74 54.01 55.08 60.68 60.70 60.15Ti02 0.98 0.94 0.95 0.84 0.84 1.16 1.24 1.25A1203 16.75 17.04 17.68 17.00 17.20 14.58 14.75 14.52Fe(T) 10.61 9.12 8.43 7.86 7.05 9.56 9.85 9.92MaO 0.23 0.19 0.13 0.11 0.10 0.19 0.18 0.18MgO 4.46 4.38 4.52 3.58 3.93 2.72 3.07 2.95CaO 6.45 5.09 9.30 7.61 7.56 4.88 3.66 3.68Na2O 4.23 5.57 4.11 4.23 4.71 5.34 5.93 5.77K2O 1.20 0.78 2.03 2.88 2.57 0.39 0.48 0.49P2S 0.21 0.16 0.21 0.17 0.18 0.19 0.20 0.18LOI 0.28 0.39 2.33 0.68 0.55 0.28 0.10 0.23SUM 99.62 99.25 99.43 98.97 99.77 99.97 100.16 99.32CIPW Normative Minerals4Q 1.03 0.00 0.00 0.00 0.00 11.05 8.52 8.95C 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Z 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02OR 7.11 4.61 12.03 17.05 15.22 2.31 2.85 2.90AB 35.79 47.13 24.47 34.96 38.19 45.18 50.17 48.82AN 23.23 19.26 23.86 18.95 18.25 14.68 12.23 12.29NE 0.00 0.00 5.58 0.45 0.90 0.00 0.00 0.00DI 6.47 4.47 17.73 15.10 15.31 7.04 3.97 4.12WO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00HY 20.29 17.07 0.00 0.00 0.00 13.92 16.56 16.25OL 0.00 1.55 8.82 7.62 7.41 0.00 0.00 0.00MT 2.31 1.98 1.83 1.71 1.53 2.08 2.14 2.16CM 0.01 0.01 0.01 0.01 0.01 0.00 0.00 0.02IL 1.86 1.79 1.80 1.60 1.60 2.20 2.35 2.37AP 0.50 0.38 0.50 0.41 0.43 0.45 0.48 0.43CC 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00SUM 98.62 98.28 96.66 97.86 •98.86 98.94 99.30 98.33161Table C.3: Major element analysis and CIPw normative mineralogy of phync and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia (continued)...FIELD NO. 6-5 6-5$ 6-5# 65* 6-7 6-7$ 8-1 8-iSMAP NO.’ W12 W12 W12 W12 W13 W13 W14 W14LAB NO. 40417 40416 40444 40411 40419 40422 40421 40427NORTHING 5467735 5467735 5467735 5467735 5467750 5467750 5467675 5467675BASTING 716385 716385 716385 716385 716360 716360 716375 716375uNrr2 7 7 7 7 7 7 7 7ROCK qDi qDi qDi qDi qDi qDi qDi qDiTYPE3SiO2 49.03 49.54 49.35 48.98 54.31 54.31 54.32 54.61Ti02 2.08 2.08 2.08 2.10 0.92 0.92 1.75 1.76A12O3 15.60 15.21 15.04 15.50 17.54 17.58 15.83 15.62Fe0(T) 11.56 11.27 11.34 11.62 8.91 8.85 9.07 9.18MaO 0.15 0.15 0.14 0.14 0.15 0.15 0.12 0.12MgO 6.55 6.35 6.27 6.51 4.36 4.38 5.81 6.00CaO 8.54 9.07 9.21 8.47 5.65 5.45 6.48 6.64Na2O 3.60 3.61 3.65 3.55 4.89 4.92 3.81 3.95K2O 1.55 1.14 1.12 1.54 2.04 2.02 1.12 1.080.44 0.46 0.42 0.46 0.17 0.17 0.31 0.31WI 0.86 0.92 0.84 0.70 0.79 0.86 0.87 0.79SUM 99.96 99.80 99.46 99.57 99.73 99.61 99.49 100.06CIPW Normative Minerals4Q 0.00 0.00 0.00 0.00 0.00 0.00 3.61 2.97C 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00Z 0.03 0.03 0.03 0.03 0.02 0.02 0.02 0.02OR 9.18 6.75 6.64 9.12 12.07 11.95 6.62 6.39AB 29.00 30.54 30.88 29.59 41.37 41.63 32.24 33.42AN 21.87 21.97 21.38 21.85 20.03 20.06 22.85 21.76NE 0.79 0.00 0.00 0.24 0.00 0.00 0.00 0.00DI 14.79 16.72 17.99 14.41 6.43 5.56 6.34 7.86WO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00flY 0.00 2.89 0.85 0.00 5.26 6.11 20.33 20.19OL 15.16 11.72 12.66 15.24 9.28 8.94 0.00 0.00MT 2.51 2.45 2.47 2.53 1.94 1.92 1.97 2.00CM 0.01 0.01 0.02 0.01 0.01 0.01 0.05 0.05IL 3.95 3.95 3.95 3.99 1.75 1.75 3.32 3.34AP 1.05 1.09 1.00 1.10 0.41 0.41 0.74 0.74CC 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00SUM 98.34 98.13 97.87 98.11 98.55 98.36 98.10 98.74162Table C.3: Major element analysis and CIPW normative mineralogy of phyric and aphyric Hedleyintrusions from the French Mine area, south-central British Columbia (continued)....FIELD NO. 81* 89-35 89-35$ 89-136 89-136$MAP NO.’ W14 W15 W15 W16 W16LAB NO. 40431 40433 40437 40434 40434NORTIIING 5467675 5468000 5468000EASTING 716375 716875 716875uNiT2 7 7 7ROCK qDi qDi qDiTYPE3Si02 54.19 57.45 57.38 54.09 54.04Ti02 1.79 0.52 0.52 0.52 0.52A1203 15.59 18.27 18.01 18.73 18.56Fef1’) 9.22 6.35 5.73 6.79 6.70MnO 0.13 0.07 0.08 0.19 0.20MgO 5.93 3.47 3.49 3.22 3.26CaO 6.63 6.59 6.59 7.86 7.87Na2O 4.00 4.67 4.44 3.86 3.98K20 1.09 1.57 1.95 2.98 2.750.31 0.15 0.14 0.32 0.33LOl 0.87 1.03 1.04 1.53 1.50SUM 99.75 100.14 99.37 100.09 99.71CIPW Normative Minerals4Q 2.39 3.53 3.82 0.00 0.00C 0.00 0.00 0.00 0.00 0.03Z 0.02 0.01 0.01 0.03 16.27OR 6.45 9.30 11.54 17.63 33.67AB 33.84 39.51 37.57 32.66 24.72AN 21.42 24.33 23.54 25.05 0.00NE 0.00 0.00 0.00 0.00 10.58DI 8.10 6.53 7.28 10.34 0.00WO 0.00 0.00 0.00 0.00 4.91HY 19.92 12.84 11.77 4.29 4.48OL 0.00 0.00 0.00 5.02 1.46MT 2.01 1.38 1.25 1.48 0.00CM 0.05 0.00 0.00 0.00 0.00IL 3.40 0.99 0.99 0.99 0.99AT’ 0.74 0.36 0.34 0.76 0.79CC 0.00 0.00 0.00 0.00 0.00SUM 98.35 98.80 98.10 98.25 97.90163Table C.4: Trace element analyses of phyric and aphyric Hedley intrusions from the French Mine area,south-central British Columbia. Values are in parts per million. Analyses were by Cominco Laboratory(Rb, Sr, Nb, Y, Ba, Sn), B.C. Ministry of Energy, Mines and Petroleum Resources Laboratory (Cr, Ni, (Do,Cu, Pb, Zn, Mo, As, Zr, Ti, V. La, Ce) and Acme Labs Ltd. (Bi, Te). Symbols “—s, N$fl I$II and “*“denote below detection limit, not analysed, field duplicate, field duplicate - chrome grinder and labduplicate, respectively.FIELD NO. 2-2 12-1 12-2 12-5 12-15 12-15$ 12-4 124$MAP NO.1 Wi W2 W3 W4 W5 W5 W6 W6LAB NO. 40412 40413 40414 40425 40429 40424 40423 40420NORTHING 5467915 5467755 5467755 5467740 5468025 5468025 5467690 5467690EASTING 716890 716435 716435 716350 716455 716455 716385 716385UNIT2 7 7 7 7 7 7 7 7ROCK Bin Bin Bin Bin Bin Bin hBin hBinTYPE3Cr 59 19 206 318 195 202 33 30Ni 17 3 82 106 67 84 <3 <3Co 46 36 43 44 39 43 26 20Cu 17 49 6 114 42 64 17 14Pb 8 13 5 <3 8 8 10 6Zn 97 38 89 80 83 83 75 85Bi 0.1 0.2 0.1 0.1 0.2 0.1 0.3 0.1Mo <10 <10 <10 <10 <10 <10 <10 <10As 368 28 28 64 5 5 2 2Te 0.1 0.2 0.4 0.1 0.4 0.1 0.3 0.1Rb 16 51 11 25 37 10 15 16Sr 939 712 244 379 394 350 590 547Nb <10 <10 12 17 11 15 <10 <10Zr 57 64 124 159 129 117 91 87Ti 3957 3117 7793 9532 9172 8513 5216 5336Y 20 15 26 26 27 27 25 26Ba 131 1309 120 256 286 245 288 322Sn <10 <10 <10 <10 <10 <10 <10 <10V 263 164 225 234 237 240 252 252La 17 <15 27 23 15 <15 <15 <15Ce 39 <15 24 42 28 23 28 231. Map number is plotted on Figure 4.6.2. Unit is identified in Table 3.1 and on Figure 4.1.3. Field classification of rock types are: Bin=aphyric basalt intrusion, hBin=hornblende phyric basaltintrusion, qDi”quartz diorite.164Table CA: Trace element analysis of phyric and aphyric Hedley intrusions from the French Mine area,south-central British Columbia (continued)...FIELDNO. 12-11 12-16 89-36 89-37 89-37$ 2-3 2-3# 2-3#MAPNO.1 W7 W8 W9 W10 W10 Wil Wil Wi!LAB NO. 40428 40432 40435 40436 40442 40415 40418 40443NORTHING 5468325 5467765 5468000 5468000 5468000 5468068 5468068 5468068EASTING 716340 716395 716875 716875 716875 717320 717320 7173207 7 7 7 7 7 7 7ROCK hBin hBin hBin hEm hBin qDi qDi qDiTYPE3Cr 37 41 35 31 29 17 17 80Ni <3 <3 <3 <3 <3 <3 <3 <3Co 26 23 21 20 17 30 24 16Cu 28 37 78 172 76 17 7 10Pb 10 8 11 8 18 <3 <3 5Zn 122 68 120 81 66 74 60 61Bi 0.2 0.2 0.1 0.2 0.1 0.1 0.1 0.1Mo <10 <10 <10 <10 <10 <10 <10 <10As 1 4 8 19 11 1 1 1Te 0.4 0.4 0.1 0.2 0.1 0.3 0.1 0.4Rb 35 <10 80 67 81 <10 21 <10Sr 456 782 789 583 674 151 172 179Nb <10 <10 <10 <10 <10 <10 <10 <10Zr 86 78 94 83 81 112 107 109Ti 5875 5635 5695 5036 5036 6954 7434 7494Y 28 24 28 21 26 39 33 39Ba 844 647 1260 1195 1085 120 230 225Sn <10 <10 <10 <10 15 <10 <10 <10V 300 280 276 245 241 154 160 158La 20 <15 17 <15 15 16 <15 <15Cc 30 21 29 27 18 <15 <15 20165Table C.4: Trace element analysis of phyric and aphyric Hedley intrusions from the French Mine area,south-central British Columbia (continued)...FIELD NO. 6-5 6-5$ 6-5# 65* 6-7 6-7$ 8-1 8-ISMAPNO.1 W12 W12 W12 W12 W13 W13 W14 W14LAB NO. 40417 40416 40444 40411 40419 40422 40421 40427NORTHING 5467735 5467735 5467735 5467735 5467750 5467750 5467675 5467675EAST1NG 716385 716385 716385 716385 716360 716360 716375 716375UNIT2 7 7 7 7 7 7 7 7ROCK qDi qDi qDi qDi qDi qDi qDi qDiTYPE3Cr 54 52 83 52 40 40 247 239Ni 61 58 61 60 <3 <3 87 83Co 43 45 42 40 21 18 32 32Cu 65 89 84 64 18 19 33 25Pb 6 8 10 5 3 15 8 6Zn 86 75 79 83 65 70 123 114Bi 0.2 0.3 0.2 0.3 0.2 0.2 0.1 0.2Mo <10 <10 <10 <10 <10 <10 <10 <10As 3 3 3 3 5 11 2 2Te 0.2 0.1 0.1 0.1 0.1 0.2 0.1 0.1Rb 50 28 54 35 30 24 <10 15Sr 677 695 699 674 672 690 974 949Nb 28 28 29 35 <10 <10 <10 <10Zr 141 141 138 142 78 79 85 85Ti 12470 12470 12470 12589 5515 5515 10491 10551Y 23 27 25 24 20 23 19 17Ba 717 534 513 711 2326 2260 544 528Sn <10 <10 <10 <10 <10 <10 <10 <10V 213 203 224 213 284 279 104 110La 34 35 41 38 <15 16 <15 <15Ce 58 67 66 67 16 25 24 30166Table C.4: Trace element analysis of phyric and aphyric Hedley intrusions from the French Mine area,south-central British Columbia (continued)....FIELD NO. 8_1* 89-35 89-35$ 89-136 89-136$MAP NO.1 W14 W15 Wl5LAB NO. 40431 40433 40437 40441 40434NORTHING 5467675 5468000 5468000EASTTNG 716375 716875 716875IJNIT2 7 7 7ROCK qDi qDi qDiTYPE3Cr 239 19 19 19 17Ni 82 <3 <3 3 3Co 33 22 24 19 21Cu 26 57 47 72 115Pb 5 3 8 53 11Zn 116 31 32 76 68Bi 0.2 0.1 0.1 0.2 0.1Mo <10 <10 <10 <10 <10As 2 7 5 2 3Te 0.3 0.1 0.2 0.1 0.1Rb 24 54 51 43 54Sr 952 689 754 1043 1076Nb <10 <10 <10 <10 <10Zr 87 64 69 140 139Ti 10731 3117 3117 3117 3117Y 17 12 13 19 18Ba 535 1087 1294 848 796Sn <10 <10 <10 <10 <10V 98 164 163 215 204La <15 <15 <15 15 <15Ce 15 21 20 23 22APPENDIX D: Electron microprobe analyses from the Hedley area, south-central BritishColumbia.Appendix D contains information on the sampling procedure, analytical method and tables ofelectron microprobe data (Ray and Dawson, 1994 and this study) for igneous garnet (Table D. 1), skarngarnet (Table D.2), skarn clinopyroxene (Table D.3), suiphide minerals(Table D.4), native gold (TableD.5) and telluride minerals (Table D.4).167168Sampling ProcedureThis study incorporates analyses (HI) prefix) from a regional mapping program (Ray andDawson, 1994) and additional analyses (thout HD prefix) from this study. Garnets from a minorintrusion (Table D. 1) were chosen to determine their composition and to compare with garnetcompositions from other geological environments. Samples from the French mine were chosen todetermine the composition of skarn related garnet (Table D.2), clinopyroxene (Table D.3), suiphides(Table D.4), gold (Table D.5) and unknown telluride (Table D.6) minerals. Samples containing mineralsof interest were prepared as polished thin sections and carbon coated. Prior to carbon coating, the sectionswere examined under a petrographic microscope and minerals of interest were marked to assist in locatingthe minerals when the section was loaded into the probe.Analytical MethodQuantitative and semi-quantitative analyses were done on a fully automated CAMECA SX-50microprobe operating in wavelength-dispersive (WDS) mode. Garnet and dinopyroxene were analyzedwith an accelerating potential of 15 kV, a beam current of 20 nA and a beam width of 2 ji. Suphides,tellurides and gold were analyzed with an accelerating potential of 20 kV, a beam current of 30 nA and abeam width of 5 i. UBC standards of similar composition to the mineral of interest were used.Microprobe data from samples prefixed with ‘HEY were reduced using the CAMECA Georef Program.Raw data from the remainder of the samples were reduced using a spreadsheet program developed atWashington State University.169Table D. 1: Microprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge , Hedleyarea, south-central British Columbia. Three part analytical number indicates sample number (first number),grain number (second number) and beam position (third number; letter c = core, m = margin and absent = notidentified).Analytical No. HD329-1-1 H1)329-1-2 HD329-1-3 HD329-1-4 HD329-l-5m HD328-1-lcWeight percent:FeO 29.29 28.94 29.41 13.66 13.71 29.19Fe203 0.62 0.76 0.89 0.14 0.36 0.90Si02 36.31 36.51 36.35 35.97 35.62 36.58CaO 3.22 3.26 3.33 2.25 2.20 3.19A1203 20.23 20.14 20.17 20.23 20.07 20.11Ti02 0.28 0.20 0.24 0.05 0.04 0.24MgO 2.72 2.66 2.78 0.15 0.17 2.75MnO 6.21 6.14 6.14 5.90 6.22 6.11Total 98.88 98.61 99.31 78.35 78.39 99.07Cations based on 12 oxygens:Fe2+ 2.003 1.980 2.005 1.079 1.087 1.990Fe3+ 0.038 0.047 0.055 0.0 10 0.026 0.055Si4+ 2.969 2.988 2.963 3.399 3.378 2.982Ca2+ 0.282 0.286 0.291 0.228 0.224 0.279Ai3+ 1.949 1.942 1.938 2.253 2.243 1.932Ti4+ 0.017 0.012 0.015 0.004 0.003 0.015Mg2+ 0.332 0.324 0.338 0.021 0.024 0.334Mn2+ 0.430 0.426 0.424 0472 0.500 0.422Sum 8.020 8.005 8.027 7.466 7.485 8.009Mole percent’:AD 2.39 2.70 3.11 0.54 1.20 3.18GR 6.56 6.56 6.14 6.12 5.21 5.76PY 10.92 10.77 11.08 0.62 0.69 11.07SP 14.17 14.15 13.90 60.98 61.26 13.98AL 65.96 65.82 65.77 31.75 31.63 66.001. Abbreviations are: Al) = andradite, GR = grossular, PY pyrope, SP spessartine, AL = alinandite.170Table D. 1: Microprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge , Hedleyarea, south-central British Columbia (continued)...Analytical No. BD328-1-2 HD328-1-3 HD328-1-4 HD328-1-5m HD328-2-lc HD328-2-2Weight percent:FeO 28.97 29.37 29.47 14.49 28.25 29.10Fe203 0.35 0.72 0.84 0.14 0.67 0.47Si02 36.33 36.67 36.72 36.03 36.70 36.18CaO 3.10 3.38 3.34 0.24 3.20 3.08A1203 20.11 20.29 20.24 20.45 20.17 20.17Ti02 0.21 0.25 0.30 0.04 0.22 0.22MgO 2.79 2.80 2.83 0.26 2.67 2.67MnO 6.07 5.78 5.79 5.69 6.45 6.02Total 97.93 99.26 99.53 77.34 98.33 97.91Cations based on 12 oxygens:Fe2+ 1.994 1.996 1.999 1.154 1.933 2.006Fe3+ 0.022 0.044 0.05 1 0.010 0.041 0.029Si4+ 2.991 2.980 2.978 3.431 3.003 2.982Ca2+ 0.273 0.294 0.290 0.024 0.281 0.272A13+ 1.95 1 1.943 1.935 2.295 1.945 1.959Ti4+ 0.013 0.015 0.018 0.003 0.014 0.014Mg2+ 0.342 0.339 0.342 0.037 0.326 0.328Mn2+ 0.423 0.398 0.398 0.459 0.447 0.420Sum 8.010 8.011 8.011 7.414 7.990 8.010Mole percent’AD 2.98 2.65 3.09 0.50 2.47 1.86GR 6.59 6.81 6.30 6.01 7.00 6.89PY 11.21 11.23 11.33 1.04 10.89 10.85SP 13.87 13.18 13.16 59.39 14.95 13.93AL 65.36 66.13 66.11 33.06 64.69 66.47171Table D. 1: Microprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge , Hedleyarea, south-central British Columbia (continued)...Analytical No. ND328-2-3 I-1D328-2-4 HD328-2-5m I{D328-3-lc IH[D328-3-2 H1)328-3-3Weight percent:FeO 28.92 29.18 13.98 28.73 29.18 29.00Fe203 0.68 0.71 0.23 0.59 0.51 0.58Si02 36.43 36.34 35.80 36.72 37.00 36.62CaO 3.28 3.40 2.05 3.07 3.02 2.97A1203 20.06 20.23 20.14 20.25 20.52 20.22Ti02 0.33 0.25 0.08 0.26 0.21 0.23MgO 2.78 2.82 0.16 2.77 2.70 2.74MnO 5.82 6.05 5.95 6.31 6.53 6.12Total 98.30 98.98 78.39 98.70 99.67 98.48Cations based on 12 oxygens:Fe2+ 1.983 1.992 1.107 1.960 1.974 1.984Fe3+ 0.042 0.044 0.016 0.036 0.031 0.036Si4+ 2.987 2.967 3.389 2.996 2.993 2.996Ca2+ 0.288 0.297 0.208 0.268 0.262 0.260A13+ 1.938 1.946 2.247 1.947 1.956 1.949Ti4+ 0.020 0.015 0.006 0.016 0.013 0.014Mg2+ 0.340 0.343 0.023 0.337 0.326 0.334Mn2+ 0.404 0.418 0.477 0.436 0.447 0.424Sum 8.003 8.023 7.473 7.997 8.00 1 7.998Mole percent1:AD 2.70 2.61 0.88 2.30 1.93 2.21OR 6.50 6.87 5.11 6.35 6.55 6.20PY 11.31 11.27 0.67 11.27 10.83 11.17SP 13.45 13.75 60.94 14.59 14.92 14.17AL 66.03 65.49 32.40 65.50 65.78 66.25172Table D. 1: Microprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge, Hedleyarea, south-central British Columbia (continued)...Analytical No. HD328-3-4 HD328-3-5m HD328-4-lc HD328-4-2 HD328-4-3 HD328-4-4Weight percent:FeO 28.88 29.01 29.14 29.21 29.00 13.83Fe203 0.66 0.70 0.54 0.67 0.62 0.33Si02 36.60 36.60 36.71 36.60 36.73 35.83CaO 3.36 3.36 3.09 3.36 3.33 2.10A1203 20.19 20.24 21.45 20.23 20.31 20.20Ti02 0.24 0.27 0.16 0.24 0.18 0.12MgO 2.83 2.78 2.72 2.70 2.77 0.14MnO 5.70 6.06 6.42 5.80 5.63 6.65Total 98.46 99.02 100.23 98.81 98.57 79.20Cations based on 12 oxygens:Fe2+ 1.974 1.976 1.958 1.994 1.979 1.088Fe3+ 0.04 1 0.043 0.033 0.04 1 0.038 0.023Si4+ 2.992 2.981 2.949 2.987 2.997 3.370Ca2+ 0.294 0.293 0.266 0.294 0.291 0.212A13+ 1.945 1.943 2.03 1 1.946 1.953 2.239Ti4+ 0.015 0.017 0.010 0.015 0.011 0.008Mg2+ 0.345 0.338 0.326 0.328 0.337 0.020Mn2+ 0.395 0.418 0.437 0.401 0.389 0.530Sum 8.001 8.009 8.009 8.005 7.996 7.490Mole percent’AD 2.46 2.61 1.93 2.48 2.24 1.24GR 7.05 6.78 6.79 6.99 7.24 4.78PY 11.48 11.18 10.94 10.93 11.22 0.57SP 13.15 13.87 14.65 13.34 13.42 61.76AL 65.85 65.55 65.69 66.26 65.89 31.64173Table D. 1: Microprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge, Hedleyarea, south-central British Columbia (continued)...Analytical No. 1103284-Sm HI)328-5-lc 1{D328-5-2 HD328-5-3 110328-54 HD32$-5-SmWeight percent:FeO 14.57 29.00 28.77 29.27 28.71 12.46Fe203 0.00 0.78 0.55 0.72 0.34 0.20Si02 36.16 36.50 36.39 36.46 36.48 35.84CaO 1.71 3.40 3.40 3.36 3.42 2.42A1203 20.48 20.19 20.25 20.30 20.32 20.21Ti02 0.21 0.26 0.24 0.28 0.25 0.07MgO 0.22 2.67 2.74 2.83 2.69 0.14MnO 5.64 6.32 6.16 6.22 5.90 7.15Total 78.99 99.12 98.50 99.44 98.11 78.49Cations based on 12 oxygens:Fe2+ 1.143 1.977 1.970 1.990 1.969 0.984Fe3+ 0.000 0.048 0.034 0.044 0.021 0.014Si4+ 3.391 2.976 2.979 2.964 2.992 3.386Ca2+ 0.172 0.297 0.298 0.293 0.301 0.245A13+ 2.263 1.940 1.954 1.945 1.964 2.250Ti4+ 0.015 0.016 0.015 0.017 0.015 0.005Mg2+ 0.03 1 0.325 0.334 0.343 0.329 0.020Mn2+ 0.448 0.436 0.427 0.428 0.410 0.572Sum 7.463 8.014 8.012 8.024 8.000 7.477Mole percent’:AD 0.39 2.84 2.14 2.68 1.51 0.75GR 4.45 6.65 7.43 6.61 8.20 6.32PY 0.92 10.73 11.06 11.27 10.97 0.56SP 60.37 14.43 14.14 14.06 13.66 63.57AL 33.87 65.35 65.24 65.38 65.65 28.80174Table D.1: Microprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge, Hedleyarea, south-central British Columbia (continued)...Analytical No. HD328-6-lc 1-11)328-6-2 HD328-6-3 HD328-6-4 HD328-6-5m HD328-7-lcWeight percent:FeO 29.12 28.38 29.14 29.27 29.22 29.07Fe203 0.51 0.72 0.94 0.82 0.80 0.88Si02 36.28 36.52 36.91 36.54 36.38 36.55CaO 3.31 3.39 3.32 3.27 3.35 3.30A1203 20.34 20.11 20.12 20.09 20.04 20.07Ti02 0.20 0.24 0.22 0.28 0.26 0.24MgO 2.80 2.74 2.78 2.83 2.77 2.82MaO 6.10 6.23 5.62 5.65 5.56 5.76Total 98.66 98.33 99.05 98.75 98.38 98.69Cations based on 12 oxygens:Fe2+ 1.993 1.944 1.981 1.999 2.004 1.986Fe3+ 0.03 1 0.044 0.058 0.050 0.049 0.054Si4+ 2.969 2.992 3.001 2.984 2.983 2.986Ca2+ 0.290 0.298 0.289 0.286 0.294 0.289A13+ 1.962 1.941 1.928 1.934 1.937 1.933Ti4+ 0.012 0.015 0.013 0.017 0.016 0.015Mg2+ 0.342 0.335 0.337 0.345 0.339 0.343Mn2+ 0.423 0.432 0.387 0.391 0.386 0.399Suni 8.022 8.00 1 7.993 8.006 8.008 8.005Mole percent’:AD 1.91 2.65 3.28 3.02 2.93 3.13GR 7.38 6.98 6.15 6.16 6.51 6.18PY 11.22 11.16 11.29 11.44 11.25 11.41SP 13.92 14.40 12.95 12.97 12.82 13.24AL 65.57 64.81 66.33 66.42 66.49 66.04175Table D. 1: Microprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge, Hedleyarea, south-central British Columbia (continued)...Analytical No. HD328-7-2 HJ)328-7-3 HD328-7-4 HD328-7-5m HD328-8-lc HD328-8-2Weight percent:FeO 12.09 13.64 14.35 14.71 28.98 29.69Fe203 0.35 0.16 0.40 0.14 0.41 0.74Si02 36.06 35.68 36.32 35.64 36.52 36.64CaO 2.46 2.25 1.86 1.80 3.26 3.25A1203 20.23 20.11 20.12 20.14 20.35 20.27Ti02 0.06 0.07 0.21 0.15 0.24 0.32MgO 0.13 0.17 0.18 0.19 2.79 2.86MnO 6.88 5.84 5.91 5.63 5.90 5.71Total 78.26 77.92 79.35 78.40 98.45 99.48Cations based on 12 oxygens:Fe2+ 0.954 1.085 1.123 1.166 1.982 2.015Fe3+ 0.025 0.011 0.028 0.010 0.025 0.045Si4+ 3.403 3.392 3.398 3.379 2.987 2.974Ca2+ 0.249 0.229 0.186 0.183 0.286 0.283Ai3+ 2.250 2.253 2.219 2.251 1.962 1.939Ti4+ 0.004 0.005 0.015 0.011 0.015 0.020Mg2+ 0.019 0.024 0.025 0.027 0.340 0.346Mn2+ 0.550 0.470 0.468 0.452 0.409 0.393Sum 7.455 7.470 7.463 7.480 8.005 8.014Mole percent’:AD 1.19 0.65 1.65 0.73 1.69 2.81GR 5.99 5.96 3.60 4.41 7.52 6.15PY 0.51 0.71 0.74 0.79 11.29 11.42SP 62.63 60.93 60.78 60.06 13.60 12.98AL 29.68 31.75 33.22 34.02 65.91 66.64176Table D. 1: M.icroprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge, Hedleyarea, south-central British Columbia (continued)...Analytical No. HD328-8-3 HD328-8-4 HD328-8-5m HD328-9-lc HD328-9-2 HI)328-9-3Weight percent:FeO 29.46 29.17 29.37 28.88 28.89 28.85Fe203 0.89 0.49 0.73 0.58 0.90 0.58Si02 36.78 36.71 36.60 36.63 36.68 36.57CaO 3.34 3.36 3.44 3.23 3.28 3.40A1203 20.23 20.27 20.26 20.25 20.11 20.37Ti02 0.35 0.27 0.18 0.26 0.24 0.25MgO 2.79 2.76 2.77 2.76 2.72 2.64MnO 6.08 5.42 5.55 6.06 6.24 6.62Total 99.92 98.45 98.90 98.65 99.06 99.28Cations based on 12 oxygens:Fe2+ 1.993 1.993 2.002 1.972 1.968 1.963Fe3+ 0.054 0.030 0.045 0.036 0.055 0.036Si4+ 2.975 2.998 2.984 2.991 2.988 2.975Ca2+ 0.289 0.294 0.300 0.283 0.286 0.296Ai3+ 1.928 1.951 1.947 1.949 1.931 1.953Ti4+ 0.021 0.017 0.011 0.016 0.015 0.015Mg2+ 0.336 0.336 0.337 0.336 0.330 0.320M_n2+ 0.416 0.375 0.383 0.419 0.431 0.456Sum 8.013 7.994 8.009 8.001 8.004 8.015Mole percent’:AD 3.32 2.03 2.55 2.25 3.20 2.19GR 5.83 7.47 7.17 6.85 6.02 7.30PY 11.13 11.24 11.17 11.18 10.99 10.59SP 13.78 12.55 12.71 13.97 14.31 15.07AL 65.93 66.71 66.39 65.75 65.47 64.85177Table D. 1: Microprobe analysis of igneous garnet from minor intrusion near Skwel Peken Ridge, Hedleyarea, south-central British Columbia (continued)...Analytical No. 111)328-9-4 HD328-9-5m HD328-10-lc HD328-10-2 Fll)328-10-3 H1)328-10-4Weight percent:FeO 14.09 14.54 29.52 29.54 27.27 29.67Fe203 0.46 0.07 0.50 0.41 1.17 0.77Si02 35.80 36.18 36.40 36.53 36.56 36.59CaO 2.13 1.72 3.18 3.14 3.25 3.55A1203 20.04 20.32 20.35 20.38 19.33 20.28Ti02 0.18 0.18 0.23 0.23 0.22 0.27MgO 0.17 0.22 2.73 2.76 2.71 2.68MnO 6.20 5.85 5.98 5.65 5.44 5.69Total 79.07 79.08 98.89 98.64 95.95 99.50Cations based on 12 oxygens:Fe2+ 1.110 1.141 2.016 2.019 1.902 2.015Fe3+ 0.033 0.005 0.03 1 0.025 0.073 0.047Si4+ 3.372 3.394 2.973 2.985 3.049 2.972Ca2+ 0.215 0.173 0.278 0.275 0.290 0.309A13+ 2.225 2.247 1.959 1.963 1.900 1.941Ti4+ 0.013 0.013 0.014 0.014 0.014 0.016Mg2+ 0.024 0.03 1 0.332 0.336 0.337 0.325Mn2-t- 0.495 0.465 0.414 0.391 0.384 0.391Sum 7.486 7.468 8.018 8.007 7.950 8.017Mole percent1:AD 1.77 0.57 1.94 1.68 4.23 2.80GR 4.28 4.32 6.95 7.17 5.48 7.07PY 0.69 0.91 10.94 11.15 11.60 10.69SP 60.93 60.56 13.65 12.98 13.23 12.91AL 32.34 33.64 66.52 67.03 65.46 66.52178Table D. 1: Microprobe analysis of igneous garnet from mi nor intrusion near Skwel Peken Ridge, Hedleyarea, south-central British Columbia (continued)....Analytical No. HD328-10-Sm HD328-11-lc HD328-11-2 Hl)328-11-3 HD328-11-4 F11)328-11-5mWeight percent:FeO 14.33 28.92 28.88 28.93 12.52 14.95Fe203 0.23 0.50 0.91 1.02 0.09 0.00Si02 35.91 36.57 36.52 36.74 35.92 35.76CaO 2.00 3.13 3.27 3.25 2.48 1.66A1203 20.15 20.34 20.08 19.91 20.26 20.25Ti02 0.17 0.20 0.26 0.30 0.06 0.15MgO 0.14 2.75 2.78 2.73 0.12 0.21MnO 5.98 6.25 6.26 5.75 6.85 5.36Total 78.91 98.66 98.96 98.63 78.30 78.34Cations based on 12 oxygens:Fe2+ 1.129 1.976 1.971 1.976 0.990 1.184Fe3+ 0.016 0.03 1 0.056 0.063 0.006 0.000Si4+ 3.383 2.987 2.980 3.001 3.395 3.387Ca2+ 0.202 0.274 0.286 0.284 0.251 0.168A13+ 2.238 1.958 1.931 1.917 2.257 2.261Ti4+ 0.012 0.012 0.016 0.018 0.004 0.011Mg2+ 0.020 0.335 0.338 0.332 0.017 0.030Mn2+ 0.477 0.432 0.433 0.398 0.548 0.430Sum 7.478 8.006 8.011 7.990 7.469 7.472Mole percent’:AD 1.04 1.92 3.24 3.71 0.38 0.28GR 4.37 6.94 5.92 5.47 6.91 4.47PY 0.59 11.13 11.19 11.17 0.51 0.36SP 60.36 14.37 14.35 13.36 68.14 59.65AL 33.14 65.64 65.31 66.30 29.06 34.74179Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia.Data are plotted in Figure 4.14. Three part analytical number indicates sample number (first number),grain number (second number) and beam position (third number: letter c = core, m margin and absent =not defined).Analytical No. 1{D170-2A-lc HD17O-2A-2 HDI7O-2A-3 HD17O-2A-4 HD17O-2A-5 HD17O-2A-6Weight percent:Si02 37.89 37.69 37.84 37.70 38.12 38.09Ti02 0.20 0.17 0.32 0.44 0.53 0.4817.51 17.85 17.65 18.16 18.45 18.38Fe203 6.26 5.80 6.09 5.10 4.76 4.93MgO 0.12 0.12 0.16 0.20 0.21 0.18CaO 35.08 35.03 34.74 34.74 35.02 35.14MnO 0.18 0.35 0.42 0.27 0.31 0.27FeO 0.82 1.08 1.45 1.53 1.22 1.14Total 98.06 98.09 98.67 98.14 98.62 98.61Cations based on 12 oxygens:Si 2.9706 2.9539 2.9508 2.9453 2.9576 2.9575Ti 0.0118 0.0100 0.0188 0.0259 0.0309 0.0280Al 1.6184 1.6493 1.6226 1.6726 1.6876 1.6825Fe’ 0.4231 0.4128 0.4519 0.3998 0.3571 0.3621Mg 0.0140 0.0140 0.0186 0.0233 0.0243 0.0208Ca 2.9470 2.9417 2.9028 2.9081 2.9113 2.9235Mn 0.0120 0.0232 0.0277 0.0179 0.0204 0.0178Sum 7.9968 8.0050 7.9932 7.9927 7.9892 7.9922Mole percent2:PY 0.85 1.20 1.49 1.32 1.46 1.26GR 78.43 78.78 76.73 79.39 81.08 81.03AD 20.72 20.02 21.78 19.29 17.46 17.711. All iron is reported as Fe203.2. Abbreviations are: PY = pyralspite (pyrope + almandite + spessartine), GR = grossular, AD =andradite.180Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. HD17O-2A-7 HDI7O-2A-8 HD17O-2A-9 HD17O-2A-lOm HDI7O-2B-lc Hl)170-2B-2Weight percent:Si02 37.88 37.77 37.89 37.54 37.91 38.06Ti02 0.48 0.31 0.49 0.40 0.41 0.33A1203 18.31 17.41 16.81 16.56 18.27 18.04Fe203 4.92 6.27 7.09 7.34 5.12 5.63MgO 0.21 0.15 0.08 0.09 0.17 0.16CaO 34.94 33.73 33.69 33.63 35.05 35.14MnO 0.37 0.59 0.41 0.37 0.34 0.26FeO 1.20 2.14 2.49 2.38 1.28 1.25Total 98.31 98.37 98.95 98.31 98.54 98.87Cations based on 12 oxygens:Si 2.9520 2.9542 2.9537 2.9497 2.9497 2.9551Ti 0.0281 0.0182 0.0287 0.0236 0.0241 0.0194Al 1.6822 1.6054 1.5449 1.5340 1.6756 1.6510Fe’ 0.3667 0.5090 0.5782 0.5904 0.3833 0.4102Mg 0.0244 0.0175 0.0093 0.0105 0.0193 0.0187Ca 2.9176 2.8269 2.8141 2.8315 2.9223 2.9237Mn 0.0244 0.0391 0.0271 0.0246 0.0226 0.0169Sum 7.9954 7.9703 7.9560 7.9644 7.9968 7.9949Mole percent2:PY 1.59 1.78 1.14 1.10 1.36 1.15GR 80.51 74.14 71.62 71.11 80.03 78.95AD 17.90 24.07 27.24 27.79 18.61 19.90181Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. HD17O-2B-3 BD17O-2B-4 HI)170-2B-5 HDI7O-2B-6 HDI7O-2B-7 1{D170-2B-8Weight percent:Si02 37.80 38.13 37.77 37.65 37.73 37.75Ti02 0.23 0.20 0.21 0.43 0.62 0.63A1203 18.04 17.47 17.32 16.85 17.48 17.67Fe203 5.59 6.41 6.39 6.81 5.78 5.61MgO 0.12 0.11 0.11 0.09 0.09 0.08CaO 34.93 35.04 34.67 34.11 34.33 34.72MnO 0.30 0.37 0.26 0.37 0.30 0.32FeO 1.50 0.67 1.01 1.54 1.62 1.48Total 98.52 98.40 97.74 97.84 97.95 98.27Cations based on 12 oxygens:Si 2.9473 2.9798 2.9719 2.9656 2.9588 2.9516Ti 0.0134 0.0119 0.0125 0.0253 0.0368 0.0373Al 1.6583 1.6098 1.6068 1.5648 1.6157 1.6286Fe’ 0.4260 0.4208 0.4450 0.5050 0.4471 0.4269Mg 0.0144 0.0124 0.0129 0.0102 0.0103 0.0094Ca 2.9177 2.9343 2.9229 2.8786 2.8842 2.9082Mn 0.0200 0.0242 0.0175 0.0248 0.0201 0.0214Sum 7.9971 7.9931 7.9896 7.9742 7.9730 7.9833Mole percent2:PY 1.10 1.20 0.99 1.13 0.98 1.00GR 78.46 78.08 77.32 74.48 77.34 78.23AD 20.44 20.72 21.69 24.40 21.67 20.77182Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. I-1D170-2B-9 HD17O-2B-lOm HD17O-2C-lc HD17O-2C-2 HDI7O-2C-3 HD17O-2C-4Weight percent:Si02 38.16 37.95 37.75 37.77 37.81 37.53Ti02 0.54 0.49 0.26 0.31 0.38 0.43A1203 18.14 18.54 17.07 17.21 17.57 17.93Fe203 5.15 4.55 6.85 6.62 6.01 5.60MgO 0.11 0.13 0.08 0.07 0.10 0.10CaO 34.64 34.52 34.90 34.78 34.64 35.03MnO 0.37 0.37 0.30 0.34 0.34 0.43FeO 1.46 1.79 1.11 1.26 1.41 1.71Total 98.56 98.34 98.32 98.36 98.26 98.75Cations based on 12 oxygens:Si 2.9653 2.9516 2.9610 2.9594 2.9582 2.9261Ti 0.0314 0.0286 0.0155 0.0181 0.0224 0.0252Al 1.6617 1.6998 1.5790 1.5895 1.6206 1.6479Fe’ 0.3955 0.3827 0.4774 0.4732 0.4461 0.4399Mg 0.0128 0.0146 0.0092 0.0087 0.0118 0.0114Ca 2.8839 2.8769 2.9333 2.9200 2.9045 2.9264Mn 0.0241 0.0242 0.0197 0.0223 0.0225 0.0281Sum 7.9747 7.9785 7.9952 7.9912 7.9861 8.0049Mole percent2:PY 1.20 1.24 0.94 1.00 1.11 1.26GR 79.58 80.38 75.85 76.05 77.31 77.67AD 19.22 18.38 23.22 22.94 21.58 21.07183Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. HDI7O-2C-5 HDI7O-2C-6 HD17O-2C-7 HD17O-2C-8 HDI7O-2C-9 HD17O-2C-lOmWeight percent:Si02 37.82 37.92 37.96 37.81 37.86 37.04Ti02 0.42 0.39 0.27 0.31 0.41 0.30A1203 18.05 17.48 17.44 17.99 18.38 18.11Fe203 5.42 6.09 6.33 5.38 4.90 5.00MgO 0.12 0.12 0.10 0.10 0.08 0.39CaO 34.93 34.45 34.87 34.73 34.89 33.01MnO 0.50 0.35 0.39 0.30 0.28 0.42FeO 1.38 1.33 0.94 1.25 1.66 3.16Total 98.63 98.11 98.30 97.88 98.47 97.42Cations based on 12 oxygens:Si 2.9457 2.9690 2.9706 2.9625 2.9459 2.9152Ti 0.0244 0.0228 0.0160 0.0184 0.0240 0.0178Al 1.6573 1.6135 1.6092 1.6616 1.6864 1.6802Fe’ 0.4079 0.4457 0.4342 0.3996 0.3950 0.5041Mg 0.0138 0.0141 0.0119 0.0112 0.0098 0.0458Ca 2.9151 2.8903 2.9242 2.9154 2.9094 2.7839Mn 0.0330 0.0233 0.0256 0.0197 0.0186 0.0279Sum 7.9972 7.9787 7.9917 7.9885 7.9893 7.9749Mole percent2:PY 1.51 1.21 1.22 1.00 0.91 2.25GR 78.74 77.15 77.53 79.61 80.11 74.67AD 19.75 21.64 21.25 19.39 18.98 23.08184Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. Hl)267-2A-lc HD267-2A-2 HD267-2A-3 HD267-2A-4 HD267-2A-5 F{D267-2A-6Weight percent:Si02 34.78 34.95 34.79 34.98 34.61 34.33Ti02 0.02 0.03- 0.01 0.05 0.01 0.022.37 2.76 3.33 2.90 0.76 0.00Fe203 27.47 26.90 25.97 26.67 29.35 30.18MgO 0.01 0.02 0.05 0.02 0.01 0.01CaO 32.67 32.66 32.57 32.81 32.35 32.80MaO 0.30 0.30 0.44 0.32 0.30 0.10FeO 0.43 0.42 0.34 0.15 0.00 0.00Total 98.06 98.04 97.50 97.91 97.40 97.43Cations based on 12 oxygens:Si 2.9683 2.9746 2.9699 2.9791 2.9957 2.9854Ti 0.0010 0.0022 0.0003 0.0031 0.0006 0.0011Al 0.2383 0.2774 0.3353 0.2909 0.0778 0.0000Fe’ 1.7950 1.7528 1.6926 1.7199 1.9115 1.9747Mg 0.0018 0.0021 0.0067 0.0026 0.0011 0.0008Ca 2.9878 2.9779 2.9788 2.9939 3.0002 3.0566Mn 0.0220 0.0214 0.0322 0.0230 0.0221 0.0077Sum 8.0141 8.0082 8.0158 8.0124 8.0091 8.0262Mole percent2:PY 0.78 0.77 1.28 0.85 0.78 0.29GR 10.94 12.89 15.25 13.62 3.13 0.00AD 88.28 86.34 83.47 85.53 96.09 99.71185Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. HD267-2A-7 HD267-2A-8m HD267-2B-Ic Hl)267-2B-2 HD267-2B-3 HD267-2B-4Weight percent:Si02 33.98 34.07 35.14 35.09 75.01 35.19Ti02 0.03 0.00 0.08 0.02 0.00 0.00A1203 0.00 0.03 3.06 2.75 0.50 2.36Fe203 29.75 30.01 26.43 26.79 5.45 27.80MgO 0.00 0.01 0.07 0.07 0.00 0.00CaO 32.76 32.77 32.74 32.94 0.47 32.74MnO 0.10 0.05 0.34 0.36 0.07 0.35FeO 0.00 0.00 0.06 0.00 0.00 0.62Total 96.62 96.93 97.93 98.01 81.50 99.05Cations based on 12 oxygens:Si 2.9811 2.9793 2.9865 2.9863 5.7105 2.9721Ti 0.0017 0.0000 0.0050 0.0010 0.0000 0.0000Al 0.0001 0.0032 0.3070 0.2758 0.0452 0.2346Fe’ 1.9642 1.9746 1.6945 1.7157 0.3123 1.8105Mg 0.0000 0.0012 0.0086 0.0086 0.0000 0.0000Ca 3.0802 3.0701 2.9816 3.0035 0.0386 2.9628Mn 0.0077 0.0035 0.0246 0.0262 0.0043 0.0251Sum 8.0351 8.0318 8.0078 8.0170 6.1108 8.0053Mole percent2:PY 0.26 0.16 1.11 1.16 0.80 0.82GR 0.01 0.00 14.23 12.69 11.84 10.65AD 99.73 99.84 84.66 86.15 87.37 88.53186Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. HD267-2B-5 HD267-2B-6 HD267-2B-7 l{D267-2B-8 HD267-2B-9 HD267-2B-lOmWeight percent:Si02 34.98 34.87 35.13 34.39 34.42 34.60Ti02 0.09 0.05 0.03 0.00 0.03 0.00A1203 2.74 2.69 3.40 0.01 0.01 0.03Fe203 27.20 27.12 26.07 30.91 30.62 30.09MgO 0.05 0.00 0.04 0.00 0.01 0.00CaO 33.47 33.16 33.25 33.17 33.07 33.07MnO 0.33 0.17 0.35 0.13 0.15 0.00FeO 0.14 0.34 0.00 0.00 0.00 0.00Total 99.02 98.41 98.28 98.61 98.30 97.80Cations based on 12 oxygens:Si 2.9547 2.9619 2.9746 2.9616 2.9707 2.9947Ti 0.0057 0.003 1 0.0018 0.0000 0.0022 0.0000Al 0.2733 0.2689 0.3393 0.0014 0.0005 0.0032Fe’ 1.7393 1.7578 1.6607 2.0030 1.9888 1.9597Mg 0.0069 0.0000 0.0050 0.0003 0.0017 0.0001Ca 3.0295 3.0176 3.0168 3.0604 3.0580 3.0662Mn 0.0236 0.0125 0.0254 0.0096 0.0106 0.0000Sum 8.0332 8.0217 8.0236 8.0362 8.0325 8.0238Mole percent2:PY 1.01 0.41 1.01 0.33 0.41 0.00GR 12.57 12.86 15.95 0.06 0.03 0.16AD 86.42 86.73 83.03 99.61 99.56 99.83187Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. 1{D267-IA-lc HD267-1A-2 HD267-IA-3 HD267-IA-4 HD267-1A-5 HD267-1A-6Weight percent:Si02 34.57 34.58 34.76 35.11 35.14 35.08Ti02 0.00 0.00 0.00 0.00 0.00 0.00A1203 0.05 0.05 0.00 0.24 0.12 0.11Fe203 29.77 30.75 30.60 30.72 30.71 30.81MgO 0.00 0.00 0.00 0.02 0.01 0.01CaO 32.71 32.88 32.95 33.17 33.01 32.99MnO 0.16 0.11 0.22 0.07 0.13 0.09FeO 0.00 0.00 0.00 0.00 0.00 0.00Total 97.27 98.36 98.53 99.32 99.12 99.11Cations based on 12 oxygens:Si 3.0056 2.9794 2.9890 2.9892 2.9984 2.9944Ti 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000Al 0.0055 0.0046 0.0001 0.0239 0.0119 0.0115Fe1 1.9476 1.9940 1.9798 1.9681 1.9717 1.9790Mg 0.0000 0.0000 0.0001 0.0021 0.0008 0.0013Ca 3.0474 3.0353 3.0361 3.0266 3.0178 3.0173Mn 0.0119 0.0078 0.0159 0.0049 0.0093 0.0067Sum 8.0179 8.0212 8.0210 8.0148 8.0099 8.0103Mole percent2:PY 0.41 0.26 0.54 0.23 0.34 0.27GR 0.28 0.23 0.00 0.97 0.26 0.31AD 99.31 99.51 99.46 98.80 99.40 99.42188Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. HD267-IA-7 HD267-1A-8mWeight percent:Si02 34.89 35.10Ti02 0.02 0.02A1203 0.05 0.00Fe203 30.70 30.41MgO 0.01 0.00CaO 32.89 33.00MnO 0.10 0.09FeO 0.00 0.00Total 98.65 98.63Cations based on 12 oxygens:Si 2.993 1 3.0087Ti 0.0010 0.0015Al 0.0050 0.0000Fe’ 1.9819 1.9611Mg 0.0011 0.0006Ca 3.0234 3.03 10Mn 0.0070 0.0066Sum 8.0 125 8.0093Mole percent2:PY 0.27 0.24GR 0.22 0.00AD 99.51 99.76189Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. 8969B-1-1 8969B-1-2 8969B-2-1 8969B-2-2 8969B-2-3 8969B-2-4Weight percent:Na20 0.01 0.01 0.00 0.00 0.02 0.01FeG 19.43 18.54 19.31 18.81 17.44 18.93Si02 33.35 35.93 36.12 35.86 36.30 35.72CaO 32.43 31.94 33.03 33.10 32.89 33.00A1203 7.71 8.70 7.28 7.45 9.03 7.45Ti02 0.94 1.13 0.83 0.90 0.79 1.14MgO 0.02 0.02 0.05 0.02 0.02 0.04MnO 0.36 0.50 0.39 0.37 0.50 0.39Cl 0.00 0.00 0.00 0.01 0.01 0.00F 0.00 0.15 0.13 0.16 0.28 0.13Cr203 0.02 0.05 0.00 0.04 0.00 0.07Total 94.28 96.96 97.15 96.72 97.27 96.89Cations based on 12 oxygens:Na 0.0012 0.0011 0.0000 0.0000 0.0027 0.0022Fe’ 1.3808 1.2669 1.3237 1.2961 1.1881 1.3025Si 2.8340 2.9351 2.9610 2.9538 2.9561 2.9391Ca 2.9522 2.7961 2.9015 2.9217 2.8703 2.9094Al 0.7726 0.8382 0.7035 0.7239 0.8669 0.7225Ti 0.0602 0.0692 0.05 10 0.0559 0.0485 0.0708Mg 0.0024 0.0026 0.0064 0.0029 0.0023 0.0050Mn 0.0261 0.0345 0.0271 0.0257 0.0346 0.0273Sum 8.0296 7.9436 7.9743 7.9802 7.9693 7.9788Mole percent2:PY 0.88 1.17 1.10 0.95 1.20 1.06GR 35.00 38.64 33.60 34.89 40.99 34.62AD 64.12 60.18 65.30 64.17 57.82 64.32190Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. 8969B-5-1 8969B-6-l 8969B-7-1 8969B-8-l 8969B-9-l 8969B-10-1Weight percent:Na20 0.00 0.01 0.02 0.01 0.00 0.01FeO 16.65 19.15 17.75 19.57 26.60 23.10Si02 36.31 36.07 36.42 36.11 34.85 35.03CaO 32.31 33.24 32.23 33.05 32.76 32.59A1203 10.50 6.98 9.61 6.79 0.92 4.32Ti02 0.75 0.88 0.82 0.73 0.00 0.07MgO 0.00 0.07 0.01 0.10 0.01 0.02MnO 0.48 0.47 0.50 0.41 0.15 0.27Cl 0.00 0.00 0.00 0.01 0.00 0.00F 0.20 0.23 0.30 0.11 0.00 0.00Cr203 0.12 0.01 0.03 0.00 0.00 0.06Total 97.32 97.12 97.66 96.87 95.29 95.45Cations based on 12 oxygens:Na 0.0000 0.0022 0.0025 0.0013 0.0000 0.0013Fe’ 1.1275 1.3 162 1.2012 1.3471 1.9075 1.6329Si 2.9393 2.9655 2.9470 2.9721 2.9885 2.9617Ca 2.8026 2.9282 2.7941 2.9151 3.0100 2.9521Al 1.0024 0.6766 0.9 163 0.6593 0.0929 0.4302Ti 0.0454 00545 0.0496 0.0449 0.0000 0.0041Mg 0.0002 0.0083 0.0008 0.0117 0.0017 0.0020Mn 0.0328 0.0330 0.0342 0.0289 0.0107 0.0190Sum 7.9503 7.9847 7.9459 7.9804 8.0113 8.0033Mole percent2:PY 1.04 1.38 1.10 1.35 0.41 0.68OR 46.03 32.57 42.17 31.51 4.23 20.17AD 52.94 66.05 56.73 67.14 95.36 79.15191Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)...Analytical No. GD6.8-1-lc GD6.8-2-1 GD6.8-3-l GD6.8-4-1 GD6.8-5-1 GD6.8-6-1Weight percent:Na20 0.02 0.00 0.01 0.00 0.02 0.00FeO 15.88 16.24 14.08 14.48 15.19 15.00Si02 35.84 36.46 36.45 35.80 36.25 36.04CaO 33.08 32.99 33.13 32.41 32.82 33.12A1203 9.67 9.36 10.60 12.20 10.81 10.34Ti02 0.51 0.49 1.09 0.50 0.46 1.11MgO 0.12 0.08 0.17 0.06 0.05 0.05MnO 0.65 0.67 0.88 0.51 0.60 0.69C 0.00 0.00 0.00 0.00 0.00 0.01F 0.18 0.00 0.16 0.15 0.16 0.19Cr203 0.00 0.02 0.00 0.05 0.00 0.00Total 95.95 96.31 96.56 96.17 96.35 96.55Cations based on 12 oxygens:Na 0.0024 0.0000 0.0011 0.0000 0.0027 0.0002Fe’ 1.0937 1.1118 0.9585 0.9860 1.0363 1.0242Si 2.9528 2.9839 2.9664 2.9157 2.9567 2.9421Ca 2.9200 2.8935 2.8891 2.8284 2.8685 2.8973Al 0.9389 0.9029 1.0170 1.1716 1.0393 0.9948Ti 0.03 18 0.0300 0.0664 0.0304 0.0282 0.0680Mg 0.0150 0.0102 0.0206 0.0075 0.0060 0.0064Mn 0.0455 0.0462 0.0609 0.0353 0.0411 0.0474Sum 8.0002 7.9786 7.9800 7.975 1 7.9787 7.9805Mole percent2:Pyral 1.98 1.87 2.75 1.32 1.51 1.78Gross 44.21 42.95 48.73 52.98 48.56 47.49And 53.81 55.18 48.52 45.70 49.93 50.73192Table D.2: Electron microscope analysis of garnet from the French mine, south-central British Columbia(continued)....Analytical No. GD6.8-7-1 GD6.8-8-1 GD6.8-9-l GD6.8-10-1 GD6.8-11-1 GD6.8-121Weight percent:Na20 0.02 0.03 0.00 0.00 0.01 0.01FeO 16.33 11.82 12.06 12.89 13.94 14.20Si02 36.27 37.05 36.96 36.72 36.43 36.77CaO 33.24 32.78 32.72 33.22 33.13 33.26A1203 9.83 14.04 13.96 11.72 11.51 11.28Ti02 0.55 0.67 0.49 0.86 0.62 0.35MgO 0.06 0.06 0.05 0.11 0.06 0.08MnO 0.45 0.77 0.85 0.79 0.86 0.82C 0.02 0.00 0.00 0.00 0.01 0.03F 0.11 0.13 0.00 0.01 0.44 0.28Cr203 0.00 0.00 0.21 0.01 0.02 0.08Total 96.87 97.34 97.31 96.32 97.02 97.15Cations based on 12 oxygens:Na 0.0032 0.0039 0.0000 0.0000 0.0009 0.0014Fe1 1.1122 0.7871 0.8051 0.8736 0.9455 0.9611Si 2.9543 2.9515 2.9504 2.9761 2.9548 2.9754Ca 2.9004 2.7975 2.7982 2.8854 2.8795 2.8840Al 0.9436 1.3189 1.3140 1.1201 1.1002 1.0762Ti 0.0337 0.0400 0.0295 0.0524 0.0378 0.0214Mg 0.0073 0.0065 0.0057 0.0128 0.0075 0.0098Mn 0.0309 0.0522 0.0575 0.0542 0.0589 0.0561Sum 7.9856 7.9575 7.9605 7.9746 7.9851 7.9853Mole percent2:PY 1.24 1.86 1.99 2.24 2.16 2.15GR 44.66 60.77 60.02 53.94 51.62 50.67AD 54.10 37.37 37.99 43.82 46.22 47.18193Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia. Data are plotted in Figure 4.15. Three part analytical number indicates sample number (firstnumber), grain number (second number) and beam position (third number: letter c = core, m = marginand absent = not defined). Symbol “—“ denotes not analyzed for.Analytical No. HD17O-1A-lc HD17O-IA-2 11D170-1A-3 HD17O-1A-4 HD17O-1A-5 HD17O-1A-6Weight percent:Na20 0.06 0.07 0.05 0.04 0.04 0.05Fe203 2.29 2.76 2.84 2.16 1.60 2.16Si02 48.66 48.33 48.16 48.24 48.69 48.46CaO 23.13 23.14 23.20 23.08 23.28 23.13A1203 0.49 0.54 0.35 0.21 0.22 0.25Ti02 0.05 0.05 0.04 0.02 0.00 0.02MgO 5.73 5.71 5.41 5.32 5.27 5.38MnO 0.54 0.49 0.56 0.62 0.56 0.64Cr203 0.00 0.02 0.00 0.00 0.03 0.03FeO 17.56 17.17 17.48 17.83 18.25 17.85Total 98.52 98.28 98.08 97.52 97.93 97.%Cations based on 6 oxygens:Na 0.0047 0.0059 0.0037 0.0035 0.0034 0.0042Fe’ 0.663 1 0.6669 0.683 1 0.6765 0.6694 0.6742Si 1.9659 1.9604 1.9633 1.9739 1.9802 1.9736Ca 1.0011 1.0058 1.0133 1.0117 1.0143 1.0091Al 0.0233 0.0260 0.0167 0.0103 0.0105 0.0118Ti 0.0016 0.0014 0.0011 0.0005 0.0000 0.0006Mg 0.3452 0.3451 0.3285 0.3243 0.3192 0.3265Mn 0.0184 0.0167 0.0193 0.0216 0.0194 0.0221Sum 4.0232 4.0281 4.0291 4.0222 4.0163 4.0221Mole percent2:JO 1.80 1.62 1.87 2.11 1.93 2.16DI 33.62 33.55 31.87 31.72 31.66 31.92lID 64.58 64.83 66.26 66.17 66.41 65.921. AU iron is reported as Fe203.2. Abbreviations are: JO =johannsenite, DI = diopside, lID = hedenbergite.194Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia (continued)...Anaytical No. HDI7O-IA-7 HD17O-IA-8 FID17O-IA-9m HD17O-1B-lc HDI7O-1B-2 HDI7O-1B-3Weight percent:Na20 0.04 0.04 0.05 0.09 0.09 0.08Fe203 2.10 2.94 1.80 2.87 1.49 2.99Si02 48.47 48.02 48.46 48.19 48.16 47.31CaO 23.31 23.29 22.96 23.17 23.06 22.78A1203 0.27 0.27 0.32 0.69 0.61 0.54Ti02 0.01 0.03 0.03 0.08 0.08 0.03MgO 5.19 5.40 5.28 5.64 5.31 5.38MnO 0.53 0.55 0.63 0.46 0.37 0.52Cr203 0.00 0.00 0.00 0.01 0.01 0.01FeO 18.12 17.21 18.25 17.10 17.85 16.96Total 98.05 97.76 97.78 98.29 97.03 96.59Cations based 0116 oxygens:Na 0.0034 0.0035 0.0043 0.0070 0.0073 0.0061Fe’ 0.6813 0.6793 0.6773 0.6677 0.6568 0.6799Si 1.9734 1.9643 1.9753 1.9553 1.9713 1.9579Ca 1.0168 1.0209 1.0029 1.0072 1.0114 1.0099Al 0.0129 0.0130 0.0152 0.0331 0.0296 0.0263Ti 0.0004 0.0008 0.0008 0.0024 0.0023 0.0010Mg 0.3 150 0.3294 0.3208 0.3408 0.3237 0.33 18Mn 0.0182 0.0191 0.0218 0.0157 0.0128 0.0182Sum 4.0214 4.0302 4.0184 4.0292 4.0153 4.0310Mole percent2:JO 1.79 1.85 2.14 1.54 1.29 1.77DI 31.05 32.05 31.46 33.27 32.59 32.22HD 67.16 66.10 66.41 65.19 66.12 66.02195Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia (continued)...Analytical No. HD17O-IB-4 HD17O-1B-5 HDI7O-IB-6 HD17O-1B-7 HD17O-1B-8 HD17O-1B-9Weight percent:Na20 0.07 0.09 0.07 0.07 0.07 0.08Fe203 2.43 2.45 3.01 3.07 1.93 3.02Si02 48.25 48.41 48.11 47.94 48.23 48.26CaO 23.21 23.25 23.29 23.22 23.02 23.41A1203 0.57 0.58 0.53 0.53 0.43 0.32Ti02 0.05 0.06 0.04 0.05 0.05 0.03MgO 5.46 5.53 5.55 5.54 5.44 5.20MnO 0.42 0.45 0.44 0.45 0.47 0.57Cr203 0.01 0.00 0.00 0.00 0.00 0.07FeO 17.53 17.42 17.03 16.96 17.70 17.51Total 97.99 98.24 98.08 97.82 97.34 98.47Cations based on 6 oxygens:Na 0.0054 0.007 1 0.0058 0.0056 0.0058 0.0065Fe’ 0.6707 0.6655 0.6719 0.6731 0.6644 0.6886Si 1.9628 1.9629 1.9583 1.9571 1.9714 1.9640Ca 1.0115 1.0102 1.0160 1.0160 1.0085 1.0207Al 0.0272 0.0279 0.0256 0.0255 0.0206 0.0151Ti 0.0015 0.0017 0.0011 0.0016 0.0015 0.0009Mg 0.3310 0.3340 0.3370 0.3371 0.3312 0.3154Mn 0.0146 0.0156 0.0151 0.0155 0.0164 0.0196Sum 4.0248 4.0250 4.0307 4.03 14 4.0197 4.0309Mole percent2:JO 1.44 1.54 1.48 1.51 1.62 1.92DI 32.57 32.90 32.91 32.86 32.73 30.81HD 65.99 65.56 65.62 65.62 65.65 67.27196Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia (continued)...Analytical No. HD17O-1B-lOm I-ID 170-iC-I I-[D170-IC-2 HD 170-3A-lc HD17O-3A-2 HD17O-3A-3Weight percent:Na20 0.06 0.06 0.07 0.07 0.04 0.02Fe203 2.53 3.76 2.47 0.00 0.00 0.00Si02 48.55 48.34 48.35 42.94 41.37 35.93CaO 23.31 23.60 23.29 22.90 22.88 22.82A1203 0.31 0.32 0.27 12.59 16.64 26.14Ti02 0.02 0.06 0.00 0.06 0.00 0.01MgO 5.28 5.25 5.55 4.10 3.54 1.79MaO 0.61 0.53 0.61 0.32 0.17 0.19Cr203 0.01 0.03 0.02 0.01 0.01 0.01FeO 17.89 17.46 17.16 12.64 10.19 3.89Total 98.57 99.41 97.79 95.62 97.84 90.81Cations based on 6 oxygens:Na 0.0046 0.0044 0.0055 0.0053 0.0034 0.0018Fe’ 0.6838 0.7048 0.6606 0.4235 0.3395 0.1314Si 1.9685 1.9547 1.9710 1.7200 1.6475 1.4501Ca 1.0130 1.0225 1.0172 0.9829 0.9762 0.9866Al 0.0148 0.0153 0.0130 0.5946 0.7810 1.2439Ti 0.0006 0.00 17 0.0000 0.0019 0.0000 0.0003Mg 0.3193 0.3166 0.3369 0.2446 0.2102 0.1079Mn 0.0211 0.0183 0.0212 0.0107 0.0059 0.0066Sum 4.0257 4.0382 4.0253 3.9835 3.9637 3.9286Mole percent2:JO 2.06 1.76 2.08 1.58 1.06 2.69DI 31.17 30.45 33.07 36.03 37.83 43.87ND 66.77 67.79 64.85 62.39 61.12 53.44197Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia (Continued)...Analytical No. HDI7O-3A-4 HD17O-3A-5 HDI7O-3A-6 I-lDI7O-3A-7 HD17O-3A-8 HD17O-3A-9Weight percent:Na20 0.05 0.07 0.09 0.07 0.08 0.09Fe203 1.09 2.43 2.16 2.41 1.73 2.01Si02 46.99 48.43 48.35 48.37 48.50 48.48CaO 23.17 23.13 23.38 23.21 23.19 23.32Al203 3.91 0.55 0.53 0.47 0.65 0.56Ti02 0.05 0.03 0.06 0.03 0.05 0.04MgO 5.24 5.53 5.43 5.41 5.27 5.33MnO 0.42 0.44 0.39 0.42 0.35 0.46Cr203 0.00 0.03 0.02 0.00 0.01 0.00FeO 16.54 17.67 17.40 17.74 18.22 17.73Total 97.45 98.31 97.83 98.13 98.05 98.02Cations based on 6 oxygens:Na 0.0037 0.0057 0.0075 0.0056 0.0063 0.0073Fe’ 0.5913 0.6734 0.6581 0.6767 0.6711 0.6634Si 1.8965 1.9641 1.9671 1.9660 1.9685 1.9685Ca 1.0022 1.0052 1.0192 1.0110 1.0085 1.0149Al 0.1859 0.0262 0.0256 0.0225 0.03 10 0.0270Ti 0.0014 0.0009 0.0017 0.0009 0.0016 0.0012Mg 0.3 155 0.3341 0.3293 0.3275 0.3 186 0.3226Mn 0.0145 0.0153 0.0136 0.0143 0.0120 0.0157Sum 4.0110 4.0247 4.0221 4.0246 4.0176 4.0205Mole percent2:JO 1.57 1.49 1.36 1.41 1.20 1.56DI 34.24 32.66 32.90 32.15 31.81 32.21HD 64.19 65.84 65.75 66.44 67.00 66.23198Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia continued...Analytical No. HD17O-3A-lOm HDI7O-3B-lc HDI7O-3B-2 HDI7O-3B-3 HD17O-3B4 HD17O-3B-5Weight percent:Na20 0.09 0.09 010 0.09 0.07 0.07Fe203 0.00 3.19 3.05 3.30 2.79 3.16Si02 43.75 47.76 47.60 47.61 47.89 47.46CaO 25.49 23.09 23.13 23.21 23.25 23.30A1203 18.49 0.57 0.65 0.64 0.69 0.61Ti02 0.01 0.05 0.07 0.05 0.06 0.05MgO 0.89 5.79 5.84 5.84 5.92 5.88MnO 0.12 0.39 0.37 0.46 0.30 0.45Cr203 0.01 0.04 0.00 0.00 0.00 0.01FeO 4.24 16.45 16.11 15.95 16.36 15.69Total 93.10 97.43 96.91 97.15 97.32 96.67Cations based on 6 oxygens:Na 0.0069 0.0068 0.0076 0.0074 0.0057 0.0057Fe’ 0. 1394 0.66 14 0.6476 0.6490 0.6445 0.6379Si 1.7205 1.9553 1.9546 1.9527 1.9557 1.9539Ca 1.0739 1.0129 1.0176 1.0199 1.0173 1.0277Al 0.8572 0.0275 0.0314 0.0311 0.0331 0.0297Ti 0.0002 0.0017 0.0020 0.0015 0.0020 0.0015Mg 0.0522 0.3534 0.3576 0.3567 0.3601 0.3607Mn 0.0041 0.0136 0.0130 0.0158 0.0102 0.0156Sum 3.8543 4.0327 4.0314 4.0340 4.0286 4.0326Mole percent2:Jo 2.11 1.33 1.28 1.55 1.01 1.54DI 26.66 34.36 35.12 34.92 35.48 35.57HD 71.23 64.31 63.60 63.53 63.51 62.90199Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia (continued)...Analytical No. HDI7O-3B-6 HD17O-3B-7 HDI7O-3B-8 HDI7O-3B-9 I-1D170-3B- HD17O-3C-lclOmWeight percent:Na20 0.08 0.05 0.12 0.06 0.04 0.06Fe203 3.22 2.83 0.00 1.24 0.00 2.50Si02 47.72 47.80 43.48 46.66 43.20 48.43CaO 23.29 23.32 24.80 22.52 25.50 23.49A1203 0.67 0.72 14.76 2.37 19.29 0.52Ti02 0.08 0.06 0.05 0.03 0.00 0.05MgO 5.68 5.54 1.99 5.11 1.01 5.58MnO 0.45 0.46 0.15 0.55 0.12 0.38Cr203 0.01 0.00 0.01 0.02 0.00 0.00FeO 16.35 16.75 7.41 17.01 3.83 17.25Total 97.55 97.54 92.77 95.58 92.98 98.26Cations based on 6 oxygens:Na 0.0062 0.0042 0.0096 0.005 1 0.0032 0.0047Fe1 0.6583 0.6596 0.2492 0.6274 0.1260 0.6611K 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000Si 1.9514 1.9538 1.7497 1.9310 1.6977 1.9631Ca 1.0207 1.0212 1.0693 0.9987 1.0738 1.0202Al 0.0325 0.0347 0.7000 0.1155 0.8936 0.0247Ti 0.0024 0.0020 0.0015 0.0009 0.0000 0.0015Mg 0.3459 0.3376 01190 0.3149 0.0589 0.3371Mn 0.0156 0.0158 0.0052 0.0193 0.0039 0.0131Sum 4.0330 4.0290 3.9036 4.0129 3.8571 4.0254Mole percent2:JO 1.53 1.56 1.39 2.01 2.09 1.29DI 33.92 33.33 31.88 32.75 31.19 33.33lID 64.55 65.11 66.73 65.24 66.72 65.37200Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia continued...Analytical No. HD170-3C-2 FID17O-3C-3 HD17O-3C-4 HDI7O-3C-5 HD17O-3C-6 FID17O-3C.7Weight percent:Na20 0.07 0.07 0.08 0.07 0.08 0.08Fe203 2.15 1.65 2.46 1.95 2.47 2.31Si02 48.26 49.04 48.36 48.31 48.00 48.13CaO 23.19 23.25 23.42 23.16 23.15 23.290.57 0.40 0.61 0.66 0.54 0.60Ti02 0.07 0.04 0.05 0.03 0.05 0.06MgO 5.66 6.13 5.59 5.70 5.68 5.72MnO 0.41 0.48 0.39 0.40 0.37 0.41Cr203 0.00 0.00 0.00 0.02 0.00 0.00FeO 17.21 17.13 17.15 17.22 16.94 16.81Total 97.60 98.20 98.10 97.54 97.28 97.41Cations based on 6 oxygens:Na 0.0058 0.0057 0.0060 0.0058 0.0060 0.0060Fe’ 0.6522 0.6273 0.6569 0.6457 0.6555 0.6445K 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000Si 1.9650 1.9756 1.96 18 1.9660 1.9630 1.9633Ca 1.0116 1.0036 1.0183 1.0098 1.0142 1.0177Al 0.0273 0.0189 0.0291 0.0318 0.0260 0.0287Ti 0.0022 0.0012 0.0016 0.0011 0.0016 0.0017Mg 0.3436 0.3680 0.3379 0.3458 0.3463 0.3476Mn 0.0143 0.0165 0.0135 0.0139 0.0128 0.0142Sum 4.0220 4.0167 4.0251 4.0199 4.0254 4.0237Mole percent2:JO 1.41 1.63 1.33 1.38 1.26 1.42DI 34.02 36.38 33.51 34.40 34.13 34.54HD 64.57 62.00 65.16 64.22 64.61 64.04201Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia continued...Analytical No. HD17O-3C-8 HD17O-3C-9 E-ll)170-3C- HDI7O-3D-1 HD17O-3D-2 HD17O-3D-3lOmWeight percent:Na20 0.09 0.07 0.06 0.01 0.00 0.00Fe203 1.88 0.00 1.54 7.78 7.70 8.45Si02 47.96 45.13 46.54 37.25 37.17 36.85CaO 23.53 24.42 22.51 33.34 33.32 33.141.31 10.04 1.89 17.01 17.04 16.91Ti02 0.06 0.02 0.05 0.33 0.39 0.40MgO 5.65 3.67 6.00 0.07 0.07 0.06MnO 0.40 0.24 0.49 0.44 0.44 0.45Cr203 0.00 0.04 0.00 0.05 0.00 0.01FeO 16.40 9.82 15.40 1.53 1.54 1.41Total 97.27 93.46 94.46 97.81 97.67 97.67Cations based on 6 oxygens:Na 0.0068 0.0055 0.0047 0.0004 0.0000 0.0000Fe’ 0.6154 0.3326 0.5845 0.2884 0.2864 0.3060K 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000Si 1.9507 1.8273 1.9383 1.5058 1.5038 1.4967Ca 1.0256 1.0594 1.0044 1.4442 1.4444 1.4425Al 0.0630 0.4794 0.0929 0.8109 0.8124 0.8096Ti 0.0020 0.0007 0.0015 0.0100 0.0119 0.0123Mg 0.3422 0.2216 0.3726 0.0041 0.0043 0.0034Mn 0.0136 0.0083 0.0172 0.0152 0.0150 0.0154Sum 4.0192 3.9350 4.0161 4.0790 4.0781 4.0861Mole percent2:JO 1.40 1.48 1.76 4.93 4.91 4.76DI 35.23 39.39 38.24 1.34 1.41 1.05HD 63.37 59.12 59.99 93.73 93.69 94.19202Table D.3: Electron microscope analysis of pyroxene from (he French mine, south-central BritishColumbia (continued)...Analytical No. HD1703D-4 I-1D170-3D-5 HD17O-3D-6 I-1D170-3D-7 HD17O-3D.-8 FID17O-3D-9Weight percent:Na20 0.00 0.01 0.02 0.07 0.06 0.08Fe203 7.72 7.21 4.55 0.00 0.00 0.00Si02 37.26 37.37 38.03 41.57 42.15 42.21CaO 33.19 33.03 32.21 27.03 25.71 26.44A1203 17.11 17.24 17.93 22.49 23.74 23.57Ti02 0.37 0.29 0.32 0.06 0.00 0.02MgO 0.07 0.08 0.05 0.02 0.01 0.01MnO 0.40 0.46 0.45 0.10 0.04 0.04Cr203 0.02 0.00 0.05 0.00 0.03 0.00FeO 1.83 1.98 3.86 1.75 0.46 1.12Total 97.97 97.66 97.45 93.09 97.21 93.48Cations based on 6 oxygens:Na 0.0000 0.0006 0.0015 0.0055 0.0045 0.0061Fe’ 0.2963 0.2858 0.2662 0.0571 0.0151 0.0361K 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000Si 1.5036 1.5084 1.5224 1.6239 1.6387 1.6284Ca 1.4352 1.4287 1.3817 1.1312 1.0710 1.0930Al 0.8140 0.8203 0.846 1 1.0356 1.0882 1.0719Ti 0.0113 0.0087 0.0096 0.0018 0.0000 0.0007Mg 0.0040 0.0048 0.0031 0.0010 0.0008 0.0006Mn 0.0138 0.0156 0.0151 0.0032 0.0012 0.0012Sum 4.0782 4.073 1 4.0457 3.8593 3.8194 3.8380Mole percent2JO 4.39 5.11 5.33 5.17 7.27 3.26DI 1.28 1.58 1.08 1.71 4.60 1.49ND 94.33 93.32 93.60 93.13 88.12 95.25203Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia (continued)...Analytical No. Hl)170-3D-lOm HD17O-3E-lc HDI7O-3E-2 F{D170-3E-3 1-1D170-3E4 HD17O-3E-5mWeight percent:Na20 0.08 0.03 0.05 0.06 0.02 0.02Fe203 0.00 3.42 2.17 1.90 4.48 5.03Si02 41.95 46.66 47.75 46.92 44.03 41.83CaO 26.30 25.19 24.25 24.66 27.17 29.31A1203 23.05 3.33 2.28 3.61 6.97 10.81Ti02 0.01 0.07 0.02 0.04 0.12 0.19MgO 0.00 5.03 5.62 5.49 4.05 2.79MnO 0.06 0.50 0.48 0.39 0.41 0.45Cr203 0.00 0.02 0.02 0.00 0.00 0.00FeO 0.96 14.00 15.32 14.09 10.21 7.15Total 92.41 98.24 97.96 97.16 97.44 97.59Cations based on 6 oxygens:Na 0.0060 0.0020 0.0037 0.0047 0.0016 0.0012Fe’ 0.03 12 0.5770 0.5825 0.5340 0.4828 0.3937K 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000Si 1.6367 1.8848 1.9252 1.8960 1.7849 1.6868Ca 1.0993 1.0903 1.0475 1.0676 1.1802 1.2664Al 1.0603 0.1588 0.1083 0.1719 0.3333 0.5141Ti 0.0004 0.0021 0.0006 0.00 11 0.0037 0.0059Mg 0.0000 0.3028 0.3378 0.3306 0.2449 0.1677Mn 0.0018 0.0169 0.0163 0.0134 0.0141 0.0152Sum 3.8357 4.0347 4.0220 4.0192 4.0455 4.0509Mole percent2:JO 5.52 1.89 1.74 1.52 1.90 2.64DI 0.00 33.77 36.07 37.65 33.01 29.09ND 94.48 64.34 62.19 60.82 65.09 68.28204Table D.3: Electron microscope analysis of pyroxene from the French mine, south-central BritishColumbia. Symbol “--“ denotes not analysed for (continued)..Analytical No. GD1O.4-1-1 GDIO.4-2-1 GD1O.4-3-1 GD1O.4-4-1 GD1O.4-5-1 8969A-1Weight percent:Na20 0.08 0.07 0.06 0.08 0.07 0.03FeO 19.25 19.68 17.00 16.94 16.94 22.51Si02 49.79 49.16 49.96 50.16 49.81 48.18CaO 23.25 22.91 23.45 23.26 23.36 22.90A1203 0.32 0.50 0.85 0.40 0.29 0.23Ti02 0.02 0.05 0.08 0.11 0.02 0.04MgO 5.92 5.96 7.45 7.84 7.71 3.34MnO 0.52 0.47 0.53 0.35 0.45 0.77Cr203 0.00 0.01 0.00 0.00 0.08 0.00Cl 0.02F 0.00Total 99.15 98.83 99.38 99.14 98.72 98.00Cations based on 6 oxygens:Na 0.0058 0.0056 0.0047 0.0060 0.0057 0.0020Fe’ 0.6418 0.6598 0.5593 0.5581 0.5616 0.7744Si 1.9846 1.9709 1.9657 1.9754 1.9742 1.9821Ca 0.993 1 0.9842 0.9886 0.9816 0.9918 1.0093Al 0.0150 0.0236 0.0394 0.0184 0.0133 0.0112Ti 0.0006 0.0016 0.0023 0.0032 0.0006 0.0012Mg 0.35 18 0.3564 0.4370 0.4605 0.4555 0.2047Mn 0.0177 0.0160 0.0176 0.0118 0.0152 0.0267Cr 0.0000 0.0003 0.0000 0.000 1 0.0024 0.0000Cl-- 0.0009F— 0.0000Sum 4.0103 4.0184 4.0146 4.0151 4.0202 4.0125Mole percent2:JO 1.75 1.55 1.73 1.14 1.47 2.65DI 34.79 34.52 43.10 44.69 44.13 20.35HD 63.47 63.92 55.17 54.16 54.40 77.00205Table D.4: Electron microprobe analysis of sulphide minerals from the French mine, south-central BritishColumbia. Three part analytical number indicates sample number (first number), grain number (secondnumber) and beam position (third number).Analytical No. DUMP-i-i DUMP-2-1 DUMP-3-1 DUMP-4-1Mineral Bornite Chalcopyrite Bomite BomiteWeight percent:Cu 55.10 34.54 60.45 59.47S 31.00 34.47 27.30 27.88Fe 13.45 30.54 12.12 12.51Pb 0.00 0.00 0.00 0.00Zn 0.00 0.00 0.00 0.00Au 0.00 0.05 0.04 0.07As 0.07 0.04 0.00 0.02Hg 0.00 0.02 0.03 0.00Mn 0.00 0.01 0.00 0.01Co 0.00 0.00 0.00 0.01Ni 0.01 0.02 0.00 0.00Sb 0.00 0.00 0.01 0.00Total 99.63 99.69 99.94 99.97TableD.5:Electronmicroscopeanalysisof goldfromtheFrenchmine,south-central BritishColumbia.Three part analyticalnumber indicatessamplenumber(firstnumber),grainnumber (second number)andbeamposition(thirdnumber).AnalyticalNo.8969A-l-l8969A-l-28969A-2-l8969A-2-28969A-2-38969A-2-48969A-2-58969A-2-6Weight percent:Au79.0179.2188.5489.3592.8291.5090.9389.015Ag20.1519.9210.3510.327.147.288.5210.410Cu0.000.000.070.040.070.020.030.075Hg0.000.000.080.000.180.180.180,051Total99.1699.1399.0499.71100.2098.9999.6799.552Au:Ag3.94.08.68.713.012.610.788.6a.’TableD.6:Electronmicroscopeanalyses oftelluride andbismuthminerals fromtheFrenchmine,south-central BritishColumbia.Threepartanalyticalnumber indicatessamplenumber (first number),grainnumber (second number)andbeamposition(thirdnumber).AnalyticalNo.8969A-l-18969A-1-238969A-1-38969A-l-48969A-1-58969A-2-l8969A-3-18969A-4-18969A-5-lMineralJoesei%Joeseite1,Joeseite,JoeseitebBismuthiniteBismuthiniteJoeseitebBismuthiniteJoeseitej,Weight percent:Bi73.9373.5473.8573.3981.1180.8574.0179.8874.06Te22.3122.4922.4422.520.010.0023.020.0022.36S3.173.193.173.0719.0119.163.0219.033.11Total99.4099.2199.4698.99100.13100.02100.0598.9099.53AnalyticalNo.MineralWeightpercentBi Te S TotalTableD.6:Electronmicroscope analysesoftellurideandbismuthminerals fromtheFrenchmine,south-central BritishColumbia(continued)....8969B-l-l8969B-2-l8969B-3-18969B-4-18969B-5-1BismuthiniteBismuthinite78.6280.010.600.0118.5418.7497.2298.7677.7474.0373.955.6722.4722.4514.863.033.0898.2799.5299.4700

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