Geology and Mineral Deposits

Energiand Mink& Division Geological Survey Branch

GEOLOGY AND MINERAL DEPOSITS OF THE QUESNEL RIVER- HORSEFLY MAP AREA, CENTRAL QUESNEL TROUGH, BRITISH COLUMBIA NTS MAP SHEETS 93A/5,6,7, 11,12,13; 93B/9,16; 93G/1; 93W4

By A. Panteleyev, P.Eng., D.G. Bailey, P.Geo. M.A. Bloodgood, P.Geo. and K.D. Hancock, P.Geo.

BULLETIN 97 Canadian Cataloguingin Publication Data Main entry under title:

Geology and mineral deposits of Ule Quesnel Riva~ Horsefly mal area, central Qnesnel Trough, British Columbia NIS map sheets 93A15,6.7.11,12,13: 93BR. 16: 93W1; 93W4 (Bulletin ; 97)

Issued bv Gecloeical- Survev Branch. Includes bibliographical references: p. VICTORIA ISBN 0-7726-2973-0 BRITISH COLUMBIA CANADA 1. Geology - British Columbia - Quesrvel Riva Region August 1996 2. Geochemistry - British Columbia - Qnesnel River Region. 3. Geology, Economic - British Columbia - Qwsnel River Region. 4. Mines and mined resources - British Columbia - Quesnel River Region. I. Panteleyev, Andrejs, 1942 U. British Columbia. Ministryof Employment and Investment m.Bhh Cohnnbia. Ceorogical Survey Branch. N.Title. V. Series: Bulletin (British Columbia. Ministryof Employmentandlnvesunent) ; 97.

QE187.G46 1996 557.11'75 w-9-9 Frontispiece. Quesnel River, viewlooking east (upstream)from the QR deposit towards Quesnel Forks British Columbia

iv Geological Survey Branch Ministry of Employment and lnvesnnent

The Quesnel and Horsefly rivers traverse the north- the easternmostpart of the map area. Metamorph,c gradein westerly trending axis of the central Qnesnel belt, also the volcanic rocksis subgreenschist, consistent with burial known as the 'Quesnel Trough'. Since 1859 the region has metamorphism. Commonlythere is extensive chl'xitization been thesite of significantplacer gold prcductiou including of mafic minerals; zeolite and calcite fill arnyf;dules and some very large-scale mining operations.The identification occur in fractures in rocks throughout the regi.on. Some of Mocksource areas for the placer gold and definition of zones of epidote, chlorite, tremolite, calcite andminor the various mineral deposittypes in this regionare the main quartz represent locally developed propylitic alteration that objectives of this field study. Recent economicinterest has can be related to nearby intrusive activity. Copper-gold and been concentrated on the Mount Polley (Caritno-Bell)al- gold mineralizationis associated witha number cf the Ikiy kalic porphyry copper-gold deposit, the QR intrusion-re- lurassic diorite and zoned alkalic gabbro to syenite sl.ocks lated propylite-type gold deposit and the Frasergold and that are intrudedalong the axisof the volcanic arc at CPW (Spanish Mountain)auriferous quartz vein prospects intervals of about 11 kilometres. in the black phyllite basal map unit. Recent road building The predominantly fine-grained clasticbasil-fill rocks related to ongoing logging inthe area provides new bedrock structurally overlie a thin, tectonically emp1acf:d oc(:anic exposures in this region of otherwise sparse outcrop. crustal slice, the Crooked amphibolite, part of the Slide Studies in the map area, all within 'Quesnel Terrane', Mountain Terrane. It defines the terrane boundary with the confirm the presence of a regional synclinal structure older metamorphic rocks of the Barkerville Subterrane (a formed within a Triassic continent-margin basin. It was subdivision of Kootenay Terrane)to the east. Middle Juras- infilled first with Triassic sediments and then Triassic to sic and (?) younger polylithic conglomeratelenses and Jurassic volcanic rocks. Together these rocks constitutethe thinly bedded, fine-grained clastic rocks are preserved in Qnesnel Trough. The basal lithologic unitsconsist of mid- narrow fault-bounded wedges along the west--rn te:rrane Triassic siliceous rocks to mainly younger pelitic, thinly boundary of the Quesnelrocks with Cache Creek Terrane. bedded deposits with overlying, more massive volcaniclas- In addition, a sinuous band ofdistinctive conglomerates of tic sediments. The younger epiclastic units pass upward or possible Cretaceousage and fluvial origin overlaps Quesnel interfinger with Upper Triassic subaqueous volcanic depos-arc rocks along Quesnel Lake and Quesnel River iln the its, mainly volcanic flow and breccia units. They are over- central part of the map area. lain, in turn, by subaqueous to subaerial Lower Jurassic volcanic flow andpyroclastic rocks and overlapping Lower Eocene extensional faulting and magmatis~ndisrupted to Middle Jurassic sedimentary assemblages.The volcanic the Quesnel Trough following a period of dc:ep tropical weathering. Graben development, with attendant ash-flow rocks, and some Early Jurassic plutons, form extensivethe magmatic edifice that defines the medialaxis of the Quesnel eruptions and lacustrine deposits, characteriu:s thi!; time island arc. period. Hydrothermal activity, possibly related to subvol- The older, submarine lavas, mainly olivine and py- canic intrusions, produced tourmaline-sericite and propyii- roxene basalts of alkalic basalt to basaltic trachyandesite tic alteration (for example, the Megabucks copper-gold composition, are overlain by both subaqueous and subaerial, prospect). Elsewhereincipient epithermal quanz-carbonate dark green-grey to maroon-purple feldspathic lavas and veining is evident. Mid-Miocene and younger basalts cov- pyroclastic deposits of trachybasalt to trachyandesite com- ered parts of the Eocene grabens and older arc rocks of position, alternatively classified as rocks of the absarokite- Quesnel Terrane, and the tectonic boundary with Cache shoshonite series or shoshonite association. Many of the Creek rocks to the west, a high-angle fault. II plac:es the lavas are characterized by analcite phenocrysts.Modal basalt flows capolder Miocene fluvial systems that contain quartz does not occur in anyof the arc rock, the majority placer gold. Both preglacial and postglacial rivers flowing of chemical analyses reveal alkalic whole-rock composi- out of the metamorphic highlands to the east have trans- tions with characteristicnormative nepheline. ported additional gold. Perhaps more importantly, post- The basal clastic rocks now form a continuous structur-glacial rivers and some of the smaller creeks have 'locally ally complex black phyllite to metapelite unit along the redistributed and concentrated gold from oldcr placer de- eastern side of the map area. The rocks are well foliatedat posits. The main bedrocksources for the place~.goldappear deeper structurallevels but pass upwardinto weakly cleavedto be in the eastern part of the study area where ('?)Late rocks. They are overlain by thick panels of the extensively Jurassic quam veins occnr in the basal black phy1l:ite unit block faulted volcanic successions. The basal sedimentary near the terrane boundary of Quesnellia and the high-grade rocks are regionally metamorphosedto greenschist facies in metamorphic rocksof the BarkervilleTerrane.

" Bullerin 97 V Brirish Columbia

vi Geological Survey Branch Ministry of Employment rmd Znveslment

TABLE OF CONTEIV'TS

Page Page SUMMARY ...... v Unit Trc. Volcaniclastic Breccia...... 26 Unit Trd .Volcanic Sandstone and'Nacke .. 26 CHAFTER 1 Units TrJa And TrJb .Massive Flows. INTRODUCTION...... 1 Agglomerate. Tuffs. Pillow Basalts Project Location and Objectives...... 1 and Mafic Dikes: Massive Project Summary and Publications...... 1 Porpbyrytic Flows.Breccia and Access ...... 2 Tuff ...... 26 Physiography...... 2 Volcanicand Epiclastic RocksUnit . la...... 26 Previous Work ...... 5 Volcanic Successions ofthe QuesnelArc ...... 27 Acknowledgments...... 6 Basalts .Unit 2 ...... , ...... 27 Alkali Olivine FyroxeneBasalt CHAPTER 2 (Unit 2a) ...... 27 REGIONAL GEOLOGY...... 7 Alkali (Pyroxene) Basalt(Unit 2b .md Tectonic Subdivisions- Belts, Terranes and ClastsWithin Unit 2c; Unit 2c) ...... 28 Tectonic Assemblages...... 7 Hornblende Pyroxene Basalt Regional Map Units and Map Patterns...... 10 2d) and 2a/2d(Units ...... 28 Barkerville Terrane (KOB)...... 10 Analcite-bearing Pyroxene Basalt Snowshoe Group(PP) and Quesnel Lake 2e) (Unit ...... 28 Gneiss (DMqQ) Gneiss ...... 10 Sedimentary Successions Capping Cache Creek Terrane (CC) 10 (CC) TerraneCreek Cache ...... Unit 2 (Unit 2f)...... 29 Cache Creek Group (MTC)GroupCreekCache ...... 10 Plagioclase-lath Pyroxene-Phyric :Basalt Slide11 Mountain (SM)Terrane ...... (Unit 2g)...... 29 Croaked Amphibolite@art of DTS) ...... 11 Polylithic 'Felsic' Breccias- Unit 3 ...... 30 Quesnellia (Quesnel) Terrane (QN)...... 11 Subaerial Basalt- Unit 4 ...... 30 Harper Ranch Subterrane(DTH) ...... 11 Overlap Units...... 36 Nicola Group(TIN) a.k.a. Quesnel Clastic Overlap Deposits.Unit 5 ...... 36 River, Horseflyor Takla Group ...... 11 Clastic Rocksin Fault Blocks - Unit 6 ...... 36 SedimentaryOverlapUnits (JHA) ...... 13 Continental Clasticand Volcanic Depsitr ...... 36 Tertiary and Neogeneto Quaternary Cover Fluvial Deposits-Unit 9 ...... 36 Rocks CpTK, NTC, Q) ...... 14 Tertiary Successions-Unit 10 ...... 37 Intrusive Suites (EJgG. EjycM. Ud. Ug. Lacustrine Sediments. Unit 10 ...... 37 mK gB. mKg) mKgB...... 14 Volcanic Flows, Ash Flows and Crystal Lithologic .Structural Patterns ...... 14 Ash Tuffs -Unit37 10a ...... Neogene Plateau Basalts and Miocene: c-3 Fluvial Channel Deposits-Units 11 GEOLOGY OF THE CENTRAL QUESNELBELT ...... 17 and lla...... 37 Map Unit Lithologies and Stratigraphy...... 17 Quaternary Deposits-Unit Qal ...... 40 Sedimentary Basin Fill, Back-Arcor Marginal Intrusive Suites ...... 40 Basin Deposits - Units 1 and la...... 19 Ahlic Gabbro-Diorite-Syenite .Unit 7 ...... 40 Metasedimentary Rocks (Phyllites)-Unit 1...... 19 Quartz Diorite/Granodiorite-Unit 7a ...... 41 Unit Tral -MicaceousQuartzite ...... 19 Quartz MonzonWAlaskite - Unit 8 ...... 42 Unit Tra2. Micaceous BlackPhyllite and Tuff ...... 19 CHAPTER 4 Unit Tra3 .Phyllitic Siltstone ...... 25 AGE OF MAP UNITS .PALEONTOLOGY .~ND Unit Tra4 .Laminated Phyllite and GEOCHRONOLOGY ...... 43 Porphyroblastic Phyllite...... 25 Microfossils ...... 43 Unit Tra5- Silty Slates...... 25 Conodonts ...... 43 UnitTra6 Graphitic . Black Phyllites ...... 25 Palynomorphs ...... 46 UnitTrb -Banded Slates and Tuffs ...... 25 Macrofossils...... 46

" Bulletin 97 vii Page Page Radiometric Dates ...... 46 Others ...... 80 Stratigraphic Summary and Facies Relationships.... 48 Propylite GoldDeposits ...... 80 QR (Quesnel River) Deposit; CHAPTER 5 MINFILE 093N121 ...... 80 PETROCHEMISTRY...... 49 The PropyliteModel ...... 81 Introduction ...... 49 Porphyry Molybdenum,and Copper Chemical Compositions. Differentiation Trends. Deposits and Related Veins CIPW Norms and Petrochemcial Associated with Calcalkaline Classifications...... 49 Stocks ...... 83 Petrochemical Variation ...... 49 Auriferous Quartz Veinsin Mehsedimentary C IPW Norms CIPW ...... 54 Black Phyllite Units ...... 83 Alkalinity: Alkalic Basaltsand Shoshonites . Frasergold Property; Terminology for Quesuel Arc Rocks ...... 55 MINFILE 093N150 ...... 83 Multi-Element Variation and Minor Element Spanish Mountain Deposits CPW Discrimination Diagrams 58 - ...... (Mariner) and Peso Claims; Discussion...... 59 MINFILE 093N043 ...... 86 Tertiary BedrockDeposits 86 CHAPTER 6 ...... STRUCTURE ...... 63 Megabucks Propery; MINFILE Regional Deformation and Folding...... 63 093N078 ...... 86 Faulting ...... 64 Possible Epithennal Targets ...... 87 Detailed Structural Studies in the EurekaDeposits Peak Other ...... 87 and Spanish Lake Areas ...... 64 Placer Gold Depositsof Horsefly and Quesnel Phase 1 Structures...... 65 River District...... 87 Phase 2 Structures...... 65 Geology of the Horsefly RiverPlacer Fie1ds ...... 90 Fractures and QuartzVeins ...... 68 Horsefly AreaPlacer Deposits (Miocene Eocene Extension and Graben Development...... 70 Channels) ...... 91 Ward's Horsefly (HarpersCamp), CHAPTER 7 MINFILE 093N015 ...... 93 METAMORPHISM ...... 71 Miocene Shaft, MINFILE 093N014 .... 93 Metamorphism of the Central QuesnelBelt ...... 72 Hobson's Horsefly; Metamorphic Assemblages- Facies and Zones...... 72 MINFILE 093N015 ...... 93 Crooked Amphibolite...... 72 BlackCreek; MINFJLE 093N01694 ...... Phyllites ...... 72 Antoine Creek; MINFILE093N017 .... 94 N icola Group MetavolcanicsGroup Nicola ...... 73 Other Placer Workings ...... 95 Conditions of Metamorphism ...... 73Deposits River Quesnel ...... 95 Bullion Pit, Including Dancing Bill CHAPTER 8 Gulch (187?-1884) and China Pit ECONOMIC GEOLOGY 75 ...... (1884-1894); MINFILE 093N025 .. 95 Lcde Deposits 75 ...... Placer Gold Composition and Lode Sources...... 97 Intrusion-Related Deposits 75 ...... Silt and Lithogeochemical Studies ...... 98 Porphyry Copper-GoldDeposits Regional GeochemicalSurveys 98 Associated with Alkalic Intrusions...... 75 ...... Lithogeochemical Sampling ...... 104 Mount Polley (Cariboo-Bell) Deposit; MINFILE 093M008 ...... 75 REFERENCES...... 107 Porphyry Copper-Gold Prospects Associated With Alkalic Stocks...... 79 APPENDICEs ...... 115 Lemon Lake (Pine. Fly. Lem); A. Composition of Pyroxene From Unit 2 ...... 117 MINFILE 093N002 ...... 79 B . Microfossil (conodont) Data for the Quesnel Kwun Lake; MINFILE093N077 Map Area ...... 119 and Beehive (Beekeeper); C . Eureka Peak - Quesnel Lake Microfossil MINFILE 093N155 ...... 79 (Conodont) Data...... 121 Shiko Lake (Redgold); MINFILE D. Microfossils (Palynomorphs) from the Quesnel 093N 058 80 093N058 ...... Map Area...... 123 BullionLode; MINFILE 093N04180 ...... E . Microfossil Data fromthe Quesnel Map Area.... 125 viii Geological Survey Branch Ministry Employment and.lnveshnent of ”

Pnge ]’nee E Petrochemistry Sample Datafor the Quesnel 3-8. Generalized geologicalmap showing units10 Map Area...... 129 and 11 - Tertiary rocks...... 24 G. Major Oxide Chemistryof Map Units...... 131 3-9. Diagrammatic stratigraphicsection and n. Replicate andDuplicate Analyses (precision and cross-section showing Tertiary and Variability) ...... 133 Quaternary map units...... 38 1. Minor Element Chemistryof Map Units ...... 135 3-10. Generalized geological map showing units7 J. Major Oxide and Minor ElementChemislq ...... 137 and 8 - intrusive rocks ...... 39 K. Quesnel CIPW Normsfor all Analyzed 4-1. Central Quesnel belt time-stratigraphic units Samples, n = 84 ...... 139 with diagnostic fossils and radiometricagm ...... 43 L. Analysis of Ferric and FerrousIron @ez3 and 4-2. Generalized geologicalmap with radiometric Fe+2), in Percent, From QuesnelVolcanic and dating sample sites;this project, age in MI...... 45 Intrusive Rocks Compared toValues 4-3. Ar radiometric ages and stratigraphic Calculated From TotalFe @eo*) ...... 145 relationships of alkalic stocks and otherdated M. Lithogemhemical Analyses (125 Assay rocks of the central Quesnel belt ...... 47 Samples), in ppm...... I47 5-1. Differentiation [email protected].) with Dl. = N. Assay Samples (Appendix M)- Locations and normative Q+Or+Ab+Ne+Ks+L.c plotted Descriptions...... 151 against Quesnel Mapunit average major 0. Platinum, Palladium and Gold Analyses...... 155 oxide values ...... 52 5-2. Differentiation [email protected].) with D.I. = FIGURES normative Q+Or+Ab+Ne+Ks+Lc plottetl 1-1. Cordilleran morphogeologicalbelts after against Quesnel Map-unitaverage minor W heeler andWheeler Gabrielse1 (1972) ...... element values...... 1...... 53 1-2. Locationof project area, major lakesand 5-3.AFM diagram showing fields for Quesnel rivers and main access routesaccessmain and rivers ...... 2 units la, 2 and 3 ...... 54 2-1. Tectonic assemblage mapof the south-central 5-4. Normative compositions,CIPW norms fcr all partColumbia of British ...... 7samples Quesnel analyzed ...... 54 2-2. Generalized geological mapof project area 5-5. Classification of Quesnel basaltson the basis showing tectonic assemblages that border of total alkalis, potassium andsilica contmts ...... 55 Quesnellia and major intrusive bodies within 5-6. NormativeAb’-An-& plot for Quesnel Quesnellia ...... 8 map-area rocks...... 55 2-3. Generalized geological mapof project area 5-7. KzO versus SiOz plots of Quesnel basaln: 56 showing stratigraphic subdivisions and major ...... intrusions of Quesnel Terrane and adjoining 5-8. Alkaline sodic andalkaline potassic suitfr ...... 56 tectonic assemblages tectonic ...... 12 5-9. Ternary plotof minor oxide analyses with 2-4. Generalized cross-sections showing structural fields for various tectonicsettings ...... 57 styles along the Quesnellia-Barkerville terrane 5-10. Ternary minor elementtectonic discrimination boundary ...... 14 andPearce after plot Cam ...... 57 3-1. Schematic stratigraphic section showing 5-11. Timinor element discrimination plot ...... 57 lithologies and ages of map units described in 5-12. Vm1 minor element discriminationplot...... 57 Quesnel troughQuesnel project area ...... 17 5-13. Comparisonof some minor element contents 3-2. Generalized geologicalmap of the Quesnel of Quesneland equivalent Nicola Group trough project area showing units1 and la - basalts ...... 57 metasedimentary rocks ...... 18 5-14. Chondrite-normalized minor elementpbt 58 3-3. Schematic section and stratigraphic ...... subdivisions after Bloodgood (1990)illuseate 5-15. Chondrite-normalized minor elementplat for correlations between the Eureka Peakand high-potassium calcalkalineand shoshonitic Spanish Lakeareas ...... 19 lavas from southern Italy compared to 3-4. Generalized geological map showingbasalts unit2 - Quesnel ...... 58 basalts ...... 20 5-16. MORB-normalized trace element plotsof 3-5. Generalized geological map showing unit3 - island arc.. and other typical suites of the: ‘felsic breccia’ ...... 21 shoshon~tlcassociation ...... 58 3-6. Generalized geological map showing unit4 - 61. Schematic illustrationof the geometric subaerial basalt...... 22 relationships betweenFI and F2 folding...... 63 3-7. Generalized geologicalmap showing units5, 62. Schematic structural cross-sections...... 65 6 and 9 - overlap units...... 23 6-3. Common veingeometries ...... 68

” Bsrlletin 97 ir British Columbia

Page Page 7-1. Metamorphic facies and zones, central 3-3. Photomicrographs ofunit 2 basalts ...... 33 Quesnel Trough (Quesnel Terrane) and 3-4. Photomicrographs of analcite basalt of unit 2e, adjoining Cache Creek Terrane and sandstone and felsic breccias of unit 3 ...... 34 Barkerville Subterrane...... 71 3-5. Photomicrographsof felsic rocks of unit 3 and 8-1. Generalizedgeological map of project area ...... 77 intrusive rocks of unit 7 ...... 35 8-2. Mount Polley(Caribm-Bell) simplified geology and proposed pit S-19outline ...... 78 6-1. Second phaseoverprint of first phase isoclinal fold ...... 66 8-3. Geology ofthe QR gold deposit...... 81 6-2. Imbricationalong the contact between the 84. Cross-sections ofthe QR gold deposit Main, Croaked amphibolite andthe Triassic black Midwest and West ...... 82 phyllites ...... 66 8-5. Generalized geological mapof project area showing locations of structurally controlled, 6-3. Second phase foldingof the gently inclined mainly (mesothermal)vein deposits...... 84 bedding hasa conjugate kink-type geometry ...... 67 8-6. Frasergold property work areas, claim 6-4. Plan view ofa slaty cleavage surface (SI) boundary and geochemical gold anomalyin defonned by F2 ...... 67 soils ...... 85 6-5. Strongly deformed quartz veins within black 8-7. Generalized geological map ofproject area phyllites ...... 69 showing locations of volcanic-hosted native 6-6. Small bedding-parallel quartz veins folded copper occurrences andother mineral deposits...... 88 about an uprightFz fold ...... 69 8-8. Generalized geological map of project area 6-7. Early formed, foldedquartz veins truncatedby showing locations of placer golddeposi &...... X9 a later, blockyvein ...... 69 8-9. Placer channels in the Quesnel Lake- 8-1. mical auriferous quartz veins at the Horsefly River district ...... 91 Frasergold property...... 86 8-10. Sketch map from Lay (1932)of probable 8-2. View of the Bullion pit, looking northwest...... 96 courses of Tertiary channelsin the Horsefly area ...... 92 rmLEs 8-11. RGS stream survey for Pb, Cu, Zn andAg. 99 ...... 4-1. Radiometric Age Determinations; 8-12. RGS stream sediment surveyfor As, Sb and Potassium-Argon Analytical Data,This Study Hg ...... 100 and Others...... 44 8-13. RGS stream sediment surveyfor U and Mo 101 ...... 5-1. Average MajorOxide Compositions ...... 50 8-14. RGSstream sediment surveyfor Co and Ni ...... 102 5-2. Average Minor Element Compositions...... 50 PHOTOS 5-3. CIPW Norms.. for Map Unit Average Frontispiece Composi~ons...... 51 Quesnel River, view lookingeast (upstream) 8-1. Principal Mineral Occurrences inthe Quesnel from the QR deposit towards Quesnel Forks...... iii Map Area, Classified inMINFILE According 1-1. View of Quesnel Lakelooking northwesterly...... 3 to Major Genetic Vpes ...... 76 1-2. Niquidet Lake, between Horsefly and Quesnel 8-2. Placer Gold ProductionSince 1864 From lakes ...... 4 Bullion Mine, EstimatedFrom Reported 1-3. Rugged topographywith bedded, Production Records ...... 97 metasedimentary Triassicrocks ...... : ...... 4 8-3. Compositions of Gold Grains Recovered 3-1.1s.pical outcrop appearance andfabric in From Placer Creeksand Lode GoldSources ...... 98 basaltic uni...... 31 8-4. Summary of Stream Sediment Data for Total 3-2. ?Lpical outcrop appearance andfabric in Sample Set, in Project Area and Proximity; ‘felsic’shoshonitic basalticrocks ...... 32 N=522 ...... 103

X Geological Survey Branch MinrstryInvestment

CHAPTER 1 INTRODUCTIOlN

PROJECT LOCATIONAND OBJECTIVES studied the basal sedimentaryfacies of the Qnesn9 volcanic arc - the black phyllite map unit. She jnvesligated the A geological mapping program inthe Cariboo region stmtigraphy, structuralsetting and auriferousvejn develop of central British Columbia, the Quesnel MineralBelt Pro- ment in the Horsefly River headwaters, Macka) River and ject, was begun in 1985 and conducted overfour succeeding Spanish Mountain areas where the basal assrmblaze of field seasons. The main thrust was to remap and re-interpret finegrained clastic rocks flanks the main Quesnel volcanic the central Quesnel volcanicbelt, also known as the Quesnel units along their eastern margin. Kirk Hanco:k mapped Trough, in the vicinity of Quesnel and Horseflylakes and to along side Pantefeyev and summarized muchof the infor- the north and south of Quesnel and Horseflyrivers (Figure mation abwt placer deposits in the study area. 1-1). A major undertaking wasto investigatethe economic Geological mapping was conducted by pace andcom- potential for gold and copper-gold deposits along the vol- pass traverses over most heights of land where outcrop canic-intrusive axis of the belt and studythe newly discov- potential was evident from study of aerial photographs. ered auriferous gold veinsin the basalclastic unit. Examination ofmad cuts and the more deeply iucised creek The project was initially funded bythe CanadalBritish gullies was effective in locating otherwise scarce bedrock. Columbia Mineral Development Agreement 1985-1990 Data wererecorded on 1:20000-scale blackand whiteaerial (MDA). In 1987 increased provincial funding enabledthe photographs, more recent1: 15 ooOcoloured photographsor project to expand alongthe trend of the Quesnel beltto both 1:20 WO-scale planimetric maps. Mapping daa and inter- the northwest andsoutheast of the original mapping. Field- preted information were plotted on 150 ooO topographic work was concluded in 1988. maps and presentedon 1:50 OOO and 1:1000MLscaIe com- This study was initiated and coordinated as a mineral pilation maps.Characteristic samples were taken fromevery deposits investigation by the senior author. He mapped mapunit to describe petrologic features and 1.0 determine mainly in the volcanic terrain in the southern part of the the whole-rock and minor element chemicalcompsitions study area between the Horsefly River and Quesnel Lake. of the volcanic and intrusive rocks.A11 macrofwsils discov- David G.Bailey was contracted seasonally during 1987 andered were submittedto the Geological Survey of Canadafor 1988 to remap the central and northern portions of the examination together with a number of colkctions from Quesnel trough from the north end of Quesnel Lake and limestones and calcareous beds containing microfossils, adjoining the Quesnel River to the northwest as far as the mainly conodonts. Hydrothermally alteredor unusual rocks Cottonwood River. Mary Anne Bloodgood, supported by were submittedfor geochemical characterizationas 'assay' MDA funding in 1986 and as a staff geologist in 1987, samples. I Stratigraphicinterpretation of thesparse and fa,ult-disrupted volcanicoutcrop data is difficult due to the similarity of lithologies but great lateral diversity in the fabric and textures of the predominantly pyroxene-phyril: rocks. How- ever, a few distinctive breccia and flow units containing analcite phenocrysts or feldspathic lavas provide readily identifiable marker units. Sedimentary units with rare fossil-bearing membersare locally intercalated I~twe,*n some of the volcanic unitsand, where present,are invaluable as time-stratigraphic markers thein volcanic suc1:essions. Con- siderable assistance in geological interpretationin !southern parts of the maparea is offered by 1968 fedmYprovincia1 1:63 360 (1 inch to I mile)aeromagnetic map!; 52396 (93N6) and 15326 (93NS). The1989 1:2SO OOO aeromagnetic map of the northernpart of the mapare:! (map 1952G. with four 1:50 OOO component sheets) reveals only highly generalized map patterns. I PROJECT SUMMARY AND figure 1- 1. Cordilleran morphogeologicalbelts after Wheeler and PUBLICATIONS Gabrielse (1972) with rocks of of the Quesnel Terrane (shaded), after Wheeleretd. (1991), shown along theeastem marginof the This report, withits 1:100 OOO geological compilation Intermontane Belt The central Quesnel Trough project area in map, summarizesthe work done inthe central Quesnel belt mainly NTS 93A is indicated by the dark pattern. between latitudes 52'15' and 53"IO' north and longitudes - Bulfefin97 I British Columbia

120O30’ and 122%’ west. Mappingextends from the bead- north and Williams Lake in thesouth (Figure 1-2). Easiest waters of the HorseflyRiver in the southeast to Cottonwood access is from the Carib00 Highway (Highway97) starting River in the northwest approximately 12 kilometres north at 150 Mile House, 25 kilometres east of Williams Lake; of the town of Quesnel.The area mapped, centred roughly there a paved all-weather road,the “Gold Rush Trail” joins on the village of Likely, covers about 4600 square kilome- the main highway. The roadsplits after 2 kilometres, intoa tres in a northwesterly-trending swath 26 to60 kilometres southern branch thatleads to the community of Horsefly,55 wide and 120 kilometres long. The 150 Do0 map sheets kilometres away, and a northern branch that goes to the completely or partially mapped are: NTS 93At5.6, I, 11, village of Likely, 80 kilometres distant. Alternateaccess to 12, 13; 93Bi9, 16 and small portions of 93Gl1 and 93W4 the headwaters of the Horsefly Riverin the southeasternpart (Figure 1-1). of the map area is from 100 Mile House. From there the Sample collections with chemical analyses and pea settlement of Black Creek on the Horsefly River can be logic data from 84 lithologic specimens, 20 macrofossil reached by this scenic route through a series of improved collections, 36 microfossil samples (6 producing cono- gravel roads that pass by Canim, Hendrix, Bosk and donts), 3 palynomorph collections and 125 geochemical Crooked lakes. Entryinto the central partof the project area determinations (assays) are tabulated in appendices at the and access to the Likely roadnear Beaver Creek can also be end of this repon. gained by way of’the Gibraltar mine road - Tyee Lake Published results of the project include: connector road fromMcLeese Lake, 43 kilometres northof Open Files (Maps) - 1990-31, (Bailey, 1990); 1989- Williams Lake. The northernmost part of the map area is 14, (Panteleyev andHancock, 1989b); 1989-20, accessible from the Quesnel-Barkerville road (Highway 26) (Bailey, 1989b) and 1987-9, (Bloodgood, 1987b). and a number of secondary roadsalong the Qnesnel River. Preliminary Maps - #67, (Bailey, 1988b). In the project area, and generallythroughoutthe central Papers - 1990-3, (Bloodgood, 1990). Quesnel Trough,there is a series of well-maintained gravel roads, a network intermittently upgraded farm and ranch Geological Fieldwork Paper Series Contributions of - access roads and numerous unimproved logging roads. Bailey and Archibald, 1990; Bailey,1989a; Lu, Lo- cal access is afforded by old loggingroads in various states 1989; Panteleyev and Hancock. 1989a; Bailey, of disrepair, rough tracks,trails and variouscattle walks that 1988a;Bloodgood, 1988;Panteleyev. 1988; can be travelled foot. Bloodgood, 1987a;and Panteleyev, 1987. on

ACCESS PHYSIOGRAPHY The area is readily accessible by road from the major The Quesnel Trough and the project area within it population centres in theregion, the towns of Quesnel inthe occupy the eastern pan of the Intermontane morphogeological belt along its boundary with the Omineca Belt. The region is part of the Cariboo Plateau, the easternmost part of the larger region of Interior Plateaus (Mathews, 1986). The trough andthe region tothe east of it form the Quesnel Highland (Holland, 1964),a physiographic transition zone of hills, valleys and low mountains, that lies between the gently undulating Cariboo Plateauthe in west andthe higher and steeper subalpine and alpine terrain of the Carib00 Mountains, part of the Columbia Mountain ranges, in the east. The largest valleys are occupiedby Quesnel and Horse- fly lakes, both large and deep bodies of clean water that sustain important fish stocks. Numeroussmaller lakes and ponds are found throughout the region. The topography and physiography are expressions of the predominant underlying bedrock units. In the western plateau region, thereare mainly flat-lying Tertiary volcanic flows of Early Mioceneto Early Pliocene basalts and associated pyroclastic and sedimentary rocks of Mathews’ (1989) Chilcotin Group.There is generally a thick cover of glaciogenic and fluvial deposits in the area or, rarely, small windows or uplifted fault blocks of the underlying Cache Creek Group. The area forms a plateau with a distinctive rollingtopography ofnorthwesterly trendingundulations 10 ~~ ~~ I ye1-2. Location of project area major lakes and rivers and to 25 kilometres across. The eastern marginof the basalts in rin access routes. themapareaismarkedbyaprominentbasalt‘rimrock’scarp

2 Geological Survey Branch Minisfry of Employment and Investment along Beaver Creek valley. Vegetation varies from pine the study area and are a major tributaryto the Fraser River forest to scrubby hardwood stands, commonly with inter- at Quesnel. The dominantly northwest-southeast drainage spersed grasslands and marshy ponds. The central and mainpattern has a subsidiary system perpendicularto it, formed area of mapping interest, the Quesnel Trough, is a hilly, by many of the tributarycreeks and secondary drainages. forested region underlain by Mesozoic volcanic and sedi- Qpical elevations of lakes and in the headwraters of the mentary rocks and some plutons (Photos1-1 and 1-2). The rivers in the Quesnel Highland, for example 2.t Crooked higher hills and mountains alongthe eastern map boundary Jake in the southeast part ofthe map area,are slighhtly more are composed mainlyof sedimentary rocksof the Mesozoic than 900 metres. The elevation at the confluence of the basal clastic assemblage, their foliated metamorphosed Quesnel and Fraser rivers in the northwest cwner of the equivalentsand the underlyinghigher grade basementmeta- project area is about 500 metres. The undulatin:; plateau in morphic rocks (Photo 1-3). the west varies from 900 to 1100 metres in elevation. The Evidence of glaciation is extensive and evident in the central part of the map area, alongthe volcanic axis of the landforms. Large areas are covered by fluvioglacial depos- Quesnel Trough, is predominantly rolling hills with :a few its, till sheets, moraines withtrains of large glacial erratics clustered heights of land rising gently to elevations around and ice-scoured, generally small,outcrop areas. Northwest- 1500 metres. The easternmost part of the area mapped is erly glacial transport is consistent throughout the area with more rugged with a number of mountains clc.se to 2000 local zones showing more westerly ice-movement trends. metres in elevation;farther to the east the highe:rt peaksare Glacial striae have a pronounced northwesterly orientation in excess of 2500 metres. with a dominant 305" ice-flow direction. Outcrop in the extensively glaciated area is relatively The overall northwesterly flowing drainage system es- scarce except along the eastern map boundary where the tablished in the map area originates in the Cariboo Moun- more severely deformed and metamorphosed rocks form tains. The largest river in the southis the Horsefly River and highland areas, ridges and mountain peaks. ofMost the area its tributaries. In the north the main rivers are the Cotton- is underlain by volcanic rocks and topography is subdued; wood and Swift. The Horsefly River and outflow from bedrock is exposed locally or where the generdly shallow Horsefly Lake drain into Quesnel Lake. Its outflow, the overburdenhas been disrupted by industrial activities, Quesnel River, and a northeast branch at Quesnel Forks, chieflythe logging and road building. Outcropsan? frequently CaribRiver, form the main river system in the centre of found along ridge crests, commonlyat the southt:astend (the

Photo 1-1. View of Quesnel lake looking northwesterly towards Likely from the Shiko Lake property. The forested low hills with intervening broad valleys are typical of the region that is underlainby the Quesnel arc volcanic rocks.

Bulletin 97 3 Photo1-2.NiquideiLake,betweenHorseflyandQuesnellakes,lookingeastwardiowardstheCaribooMountains.Thesubduedtopography is typical of the area of basin-fill Triassic sedimentary rocks of unit 1 that underlie the Quesnelarc volcanic deposits.

Photo 1-3. Rugged topgraphy with bedded, metasedimentary Triassic rocks in the eastern part of the map area near the Quesnellia - BarkerviUe terraneboundary. View to east towards Eureka Peak,elevation 2426 metres.

4 Geological Survey Branch 5Invesrmenf upice or stoss side) of the glaciated ridges. Bedrockis also Quesnelbelt rocks, forexample, Nelson eral. (15’91,1992). exposed insome of the more deeply incisedriver and creek Equivalent rocks to the south, mainly between Kamloops gullies and locally along lake shores. Overall there is an and Princeton, are generally referred to as Nicola Group extensive wver of glacial, fluvioglacial and fluviaI deposits(Schau, 1970; Preto, 1977,1979; Mortimer,1987). The that support forest resources of good quality. Timber has rocks mapped during this project in the centr;ll Qu(:snel been extensively harvested throughout muchof the area and Trough havebeen variously correlated witheithx TalJa or the cutblocks, especiallythe fire breaks along theirperime Niwlarocks.Bailey(1978)poiutedoutthesimilarityofthe ters, are places where bedrockis frequently exposed. Quesnel volcanic units withboth the Nicola Grouprocks to the south andthe TakIa Group rocks to the north but did not PREVIOUS WORK indicate any preferred correlationor inclusion OF his Ques- ne1 area map units with either group.He subsequently Triassic rocks near Kamloops tothe south of the Ques- referred to them as Nicola Group (Bailey, 1983a). In this ne1 area were first described by G.M. Dawson in 1877 study we continueto correlate our map units with the Nicola (Dawson 1877,1879). In 1887 Amos Bowman recognized Group simply to emphasizethe association of these rocks the volcanic nature and Mesozoic ofage rocks in the Ques- with’Quesne1Terrane. The term Takla leads tc. ambilguity ne1 River region. He referred to the volcano-sedimentary because in northern British Columbiait has be:n used for units as the “Quesnel Riverbeds” (Bowman, 1889). Cock- rocks in both Quesnel andStikine terranes. field and Walker (1932) mappeda portion of the same belt The alkalic nature of the volcanic rocks in Quesnellia, to the west ofthe Quesnel Forks placermining district. Their and their related plutons,became evident during the1970s work supported Bowman’s conclusions aboutthe distribu- largely fromthe work by Fox (1975) and near Princeton by tion of regionalmap units. Cockfield and Walker described Preto (1972, 1977, 1979). Similar rocks in the no.rthem the layered and intrusive units in more detail and notedthe Quesnel Trough were described by Koo (19158). Meade presence of syenites. Wlth the use of faunal collections they (1977) and Gamett (1978). Detailed mapping and petro- resolved that Jurassic argillites are interbedded with the chemical studies theof alkalic rocks were done lby Lel’ebure purplish brown volcanic successionsthe Moreheadin Creek (1976), Morton (1976) and Bailey (1978). Modimer (1986, area. 1987) has investigatedthe major andminor element petro- The broad extent of Triassic (and some associated chemistry of the volcanicrocks. He has discussed the large- Jurassic) arc rocks as part of a volcanic belt that is virtually scale correlations of the map units and concludes that continuous throughout’the Canadian Cordillera was docu- chemically equivalentrocks extend far to the south in the mented inthe 196Os, mainly by workersfromthe Geological United States. The relationship inthe belt between aIkalic Survey of Canada. Theterm ‘Quesnel Trough’ wasfmt used volcanism, plutonism and related mineralizathn ha:$ been by Roddick er al. in 1967. Comprehensive regional studies discussed by Barr et al. (1976). Hodgson et al. (1976) and in the Quesnel Riverarea during the late 1950s and 1960s Bailey and Hodgson (1979). In the northern part of the c~pper,1959,1978; Campbell, 1961,1963; andcampbell Quesnel Trough similar rocks in the Mount Iblilligan are and Campbell, 1970)are summarized by Campbell (1973, (NTS 93K93N) are discussedby Nelson et al. 1:1991., 1992, 1978) anddiscussed by Souther (1977). Campbell referred 1993) and Nelson and Bellefontaine (1996). to the volcano-sedimentary units as the ‘Quesnel River The boundary of the Intermontane - Ominxa morpho- Group’. geologica1 belts or, alternatively, the Quesndlia - Bark- A detailed geological descriptionand definition of re- erville terranes, has been subjectthe of a numbx of studies, gional stratigraphyin the central partof this study area was mostly unpublished, concerned mainly with the tectonic done during the 1970s by Morton (1976) and Bailey (1976, evolution, structural development and metamorphic ‘histow 1978). Morton interpreted the volcanic assemblage in the of the region (Campbell, 1911; Montgomer/, 1918; Fil- Horsefly Lake area, designated by him as the ‘Horsefly lipone, 1985;Elsby. 1985;Carye.1986;Struik. 1986,1988a; Group’, to be a cyclical sequenceof alkalic volcanics gen- Bloodgood, 1987c;Rees,l981,1987;Radloff, 1989).Much erated by CNS~rifting. Bailey, on the other hand, consid- of the workis summarized by Ross et al. (1985,1989) and ered that the rocks formed in an island arc, above a McMullin ef al. (1990). To the east of the Quesnel belt, in convergent plate margin. Bailey’s mappingthe in Morehead the Carib00 Mountains of the Barkerville Subterrane, the Lake area established a regional stratigraphy that servesas Upper Proterozoic through Paleozoic stratigraphy. smc- a geological mapping standard and reference frameworkfor tures and metamorphic history havealso been extensively this project as well as other geologicaI studiesin the region. studied(Sutherland Brown, 1963; Fletcher, 1972; Engi, His stratigraphic successionis demonstrable and reliable in 1984;Elsby, 1985 Getsinger, 1985; Montgomery, 1985; the map area and is generally applicableto other parts ofthe Ganvin,1987; Lewis, 1987). Major recent advances in Quesnel trough. understandingoftheareahavecomefromworkduring1980 Wlthin the Quesnellia tectonostratigraphic terrane in to 1986 by L.C. Struik of the Geological Survcyof Canada, north-central British Columbia, commonly referredto as the summarized in Struik (1986, 1987, 1988a.b). Two other northern extension ofthe Quesnel Trough,the term ‘Takla’ comprehensive and insightful summaries mi discussions or Takla Group has been applied to rocks identical to the are those of Rees (1987) and McMullin (1990).The major

” Bulletin 97 5 British Columbia ~ ~~~ regional tectonostratigraphic units that make up the map by electron microprobeon gold grains were performedby area and the terminology of the terranes - Quesnellia, John McKnightat TheUniversity of British Columbiaand Stikinia,Cache Creek, Slide Mountain,Barkerville, on pyroxene crystals by Mitch Mihalynukat the University Kootenay and others, are described by Monger ef af. (1991). of Calgary. Potassium-argon radiometric dating was done Interest in the mineral potential of the area has been by Joe Harakal at TheUniversity of British Columbia and evident since 1859 when placer gold was discovered near Ar-Ar dating by Doug Archibaldat Queens’ University. the site of present-day Horseflyand elsewhere in the Ques- A number ofexploration geologists, most notablyPete ne1 River drainage system. The first reports on the economic Fox and John Kerr,shared their knowledge aboutthe project potential of the district were preparedafter a reconnaissance area and, ina number of cases, provided data andreports to of the area by G.M. Dawson in 1894. A record of annual the authors. Addition valuable information, discussions, gold production and mining activity has been kept since assistance and hospitality were providedby Rob Cameron, 1874 and published inthe Annual Report of the Ministerof Vin Campbell, Rudi Durfeld, Geoffrey Goodall, Charlie Mines. Reviews of the major placer mining operations at Greig and Bill Morton.A number of claim owners, prospec- Cedar Creekwere done by Johnston (1923), Quesnel Forks tors and placer operators providedaccess to their properties, area by Cockfield and Walker (1932) andthe Horsefly River and in some cases, rock and mineral samples and tours of and other areas by Lay (1939). Recent reviews of the geo- their operations. The visit with Lyle Shunter at his Black logical settings and stratigraphyof gold placers inthe Qnes- Creek placer mine and discussion about Beaver Valley ne1 Trough and Carib00mining district to the north are those placer creeks withthe late Milt Lonneberg were especially of Levson and Giles (1991,1993). infonnative. Land holders throughout the area were consis- The first synopsis of lode mineral potential in the tently cordial and helpful with information about local ac- Quesnel Trough was by Campbell andlipper (1970). Bed- cess, outcrop locations and placer mining history. Horsefly rock exploration in the area was active during the late 1960s residents Susan andBill Hall extended their hospitality at and throughout the 1970s mainly for copper and copper- the Birch Bay Resort on Horsefly Lake. James Allard ofgold deposits (Saleken and Simpson, 1984). During that fered boat launching facilities at his family property on time, the Cariboo-Bell (Mount Polley) porphyry copper- Horsefly Lake and provided site information and rocksam- gold deposit was located (Hodgsonet aL, 1976). Explora- ples from a new quany in the area. tion activity peakedin the early 1980s after release of the Lu Jun ofthe Ministry of Metallurgical Industry, Hefei 1980 Regional Geochemistry Survey (RGS) and recogni- City, People’sRepublic of China, a visiting scholar funded tion of the district’s lode gold potential, as indicated by in 1987/1988 by World University Services of Canada, discovery of the volcanic-hosted, propylite-associatedQR conducted somefield investigations ably assistedby Mike gold deposit (Fox et al., 1986; Melling eful.;1990; Foxand Fournierof the Ministry. The work withinthe central Qnes- Cameron, 1995). Discovery exploration of auriferous and ne1 belt in the vicinity of Cantin Creek was in an area of quam vein deposits in the Spanish Lakeand Mackay River economic interest investigated by Pete Fox; the use of his areas focussed attentionon the gold potential of the basal data and maps is acknowledged. This work (Lu, 1989) has black phyllite units. been incorporated in the regional 150 OOO and 1:lW OOO geology maps. ACKNOWLEDGMENTS Ministry employees working on a seasonal basis as Discussions about the geology of the Nicola beltat the field and mapping assistants were: John Nicholson, Kari outset of this project and enlightening observations inthe Marks, Lany Elgaa, Giovanni Pagliuso,Mike Game11 and field were provided by Bill McMillan and Vc Preto. Ted Jan Hammack. Analytical work wasdone or expedited by Faulkner, Regional Geologist inPrince George, introduced the Analytical Sciences Laboratory, Geological Survey the writers to the project area and a number of the main Branch.ShaunPattendenassembledmuchofthesamp1eand mineral deposits. early analytical data.We acknowledge the assistance in data Macrofossils and microfossils submitted to them were assembly and computer processing from colleagues Chris expertly identified, respectively, by Howard Tipper and Ash, Wayne Jackaman, Ray Lett, Don MacIntyre, Aaron Mike Orchard of the Geological Survey of Canada. Terry Penipas and Steve Sibbick. Editorial comments about draft Poulton and Tim Tozer provided consultations on certain manuscripts, by John Newel1and Brian Grantare incorpo- fauna. Glen Rouse of The University of British Columbia rated in this report. The geological compilation mapswere identified palynomorphs.Bert Struik of the Geological Sur- completed by Martin Taylor. A special mention is reserved vey of Canada provided insights into many facets of regional for Victor Koyanagi whohas generated mostof the illustra- and structural geologyas did John Ross and Jeff Fillipone tions, tables, appendices and draft copies of the maps pre- of The University of British Columbia. Specialized analysessented here.

6 Geobgical Survey Branch Ministry of Employment and Znvestmenr

CHAPTER 2 REGIONAL GE0LOG.Y

TECTONIC SUBDMSIONS - BELTS, structural, as does Bloodgood (1988). On the other hand, TERRANES AND TECTONIC Struik(1981,1985a)referstoadepositionalcon~lctinr;ome places. Also Rees (1987) suggests that the two map units ASSEMBLAGES have a depositional contact and were linked zs a single The Canadian Cordilleracan be divided into five major composite terrane by the Late Triassic. He considers the longitudinal morphogeological belts of generally similar amphiboliteto be correlative with rocks of the Slide Mybun- physiography and geology;from west to east these are the tain Terrane butrefers to it as the 'Antler Formation'in (order Insular, Coast, Intermontane, Omineca and Foreland belts to supress the implication that it might be tectonically :repa- (WheelerandGabrielse, 1972;seeFigure1-1).Thebeltsare rated from Quesnellia. Basementfor Quesnellia .is probably now interpreted to be made up of a number of geologic rocks of the Harper Ranch (QNH) Subterranc: (Monger, terranes representing crustal blocks of fundamentally con- 1977; Struik, 1986; Monger ef ai., 1991). These are De- trastinghistories~ongeretai,,1991;WheeleretoL,1991). vonian to Permian oceanic marginal basin or an: volcanics Terranesarecharacterized(JonesefaL,1983;Keppie,1988) and sediments that locally contain mafic intrusion!; and by internally continuous geology, including stratigraphy, alpine-type ultramafic rocks. No Harper Ranch rocks are structure, fauna, metamorphism, igneous petrology, geo- known to crop out in the project area. Along the Eureka physical properties, paleomagnetic record and metallogeny. thrust, the eastern boundary of Quesnel Terrane, rocks of The te~~sare commonly bounded byfaults and melanges Quesnellia are superimposedon the intenslydefo:rmed, representingtrench complexes or (collisional) suture zones. variably metamorphosedProterozoic andPaleozoic pericra- Neighbouring terranes maybe far-[ravelled and exotic and tonic rocks of theBarkerville Subterrane (KOB). The west- therefore have distinctivegeological records. Alternatively, em part of the Intermontane Belt, Stikinia (ST), is separated if the terranes are similar they maybe distinguished only by the presence of telescoped oceanic lithosphere along their ', boundaries. In mostof the Cordillera, terrane and belt j*/!I! .*:.. boundaries coincide but locally terranes transect the ;9 boundaries of belts. Eleven allochthonousterranes in additionto the ances- tral North American craton have been described in the Canadian Orogen (Mongerel ai.. 1982,1991). Some of the terranes, or parts of them that are of uncertain origin with respect to North America, have been referredto as 'suspect terranes' (Coney ef aI., 1980). The terranes have been assembled within ascenario of continent-margin amalgama- tion and accretion summarizedby Monger (1993). This study has investigated an area that lies along the - eastern margin of the Intermontane Belt along its tectoNc boundary with the Omineca Belt. projectThe area is almost entirely within Quesnellia (QN), sometimes alternatively referred to as Quesnel Terrane (Figure 2-1). The western 8p? terrane boundary of Quesnellia with Cache Creek (CC) rocks is marked bya zone of high-angle, strike-slip faulting that is probably the southern extension of the Pinchi fault system (Gabrielse, 1991). Along the eastern margin of the map area rocks of Quesnellia and a thinslice of underlying 'Crooked amphibolite', part of the Slide Mountain Terrane - (SM), are structurally coupled and tectonically emplaced byFiL the Ewka thrust onto the BarkervilleSubterrane (KOB) of British Columbia including QGsnelbrojectarea and surroinding the Omineca Belt (Struik, 1986,1988a). region; tectonic assemblages arethose of Wheeler md McFeeley The predominantly Triassicand Early Jurassic volcanic (1991). Terranes: BR - Bridge River; CAc - CaritWx, Sul;,terrane, partofCassiar,CC-CacheCreek;HR-HarperRan:hSub,terrane; M and related volcaniclasticrocks that characterize Ques- KO - Kwtenay; KOB ~ Barkerville Subtenme;MT .Methow; NA nellia overlie a thin, discontinuous slice of Crooked amphi- -North America; SM -Slide Mountain. T - Tertiary overlap units; bolite (Campbell, 1971). Struik (1986, 1988a) regards the older (Jurassic) plutons- hatchured pattern;younger (Cre%,acaus) amphiboliteasthebasalunitofQuesnelliaandconsidersthe plutons ~ cmssed pattern. Rocks of Quesnel Terrane are shownin contact between Quesnel rocks and the amphibolite to be dark grey pattern.

Bulletin 97 7 MAP UNITS

NTS S3.W 12 and alts of 931US,7.11.13,'938/9.~30/1.93H/4

Figure 2-2. Generalized geological map of project area showing tectonic assemblages that border Quesnelliaand major intrusive bodies within Quesnellia. from Quesnelliaby rocks of theCache Creek Terrane (CC). pianintrusiveunit(Mottensenetal., 1987;Montgomeryand It is composedof mainly Mississippianto Middle Triassic Ross, 1989).FurthertotheeastoftheBarkervilleSlubterrane oceanic and island arc volcanics and sediments. The pres- are Kaza and Carib00 Grouprocks of the Upper Proterozoic ence of accretionary prism mblange and alpine-type ul- to Carboniferous Carib Subterrane (CAc), a continental tramaficassemblages,temneboundariesalongmajorfaults margin assemblage. To thewest of Quesnellia and ina small and the presence of Tethyan fauna attestto the exotic and part ofthe area mapped(see Figure 2-2) are Permian and(?) complex origin ofStikinia. older limestone and Mississippianto Upper Triassic :redi- Terranes of the Intermontane Belt - Stikinia, Cache mentary rocks of the Cache Creek assemblageINTC), an Creek and Quesnellia, collectively called (amalgamated) oceanic milange. Two other minor map unitsthe in norihern Supemrrane I, were assembledby the Early Jurassic won- part of the Quesnel Trough include small fault-bounded, ger et al., 1972, 1982; Monger, 1993). This conclusion is fragments of tectonic assemblages. These are oceanic ul- based largelyon dated crosscutting plutons. Quesnellia and tramafic rocks (DTUo), part of the Slide Mountain Group, Slide Mountain terranesare tied byLate Triassic to Middle exposed alonga northern segmentof the Eureka thrust, and Jurassic overlap assemblages. The Stikinia and Quesnellia a small wedge ofCambrian shale, sandstone and limestone arc assemblages and Cache Creek oceanic m6lange were (PCG))byDragonLakenearQuesnel,reportedonbylIEpper accreted to terranes of North American afftnity by latest (1978) and Struik (1984b). Early to Middle Jurassic time, based on ages of magmatic Some parts ofthe main tectonic assemblagzs inQues- emplacements (Monger et al., 1982; Armstrong 1988; 01- nellia and the adjoining terranesare extensively overlapped dow et ul., 1989). by younger successionsof sedimentary and volcanic rocks The fundamental geologic components that make up and intruded bypost-accretionary plutons. Within Ques- the the terranesare referred to as 'tectonic assemblages' ne1 Trough, near Quesnel and nearits western margin along (Wheeler and McFeely, 1991; Monger et al., 1991). The the Fraser River, these units include Lower ;md Middle assemblages represent rocks depositedin specific tectonic Jurassic arc-derived clastic rocks(JHA). Th,: rock .s are settings during certain periods of time and, therefore, are considered (Wheeler and McFeely, 1991) to bc equivalent commonly boundedby unconformities or faults. They rep to the Hall and Ashcroft formations of southeastern and resent distinctive successions of stratified rocks and other southern Quesnellia. This unit in the Quesnel River area characteristic lithologies, mainly coeval metamorphic, plu- contains a number of undifferentiated clastic successions tonic and ultramafic rocks.The assemblages are categorized including rocksas young as Cretaceous. Subae~ialvolcanic intermsoftheirpredominantdepositionalsettiugorposition rocks and the clastic aprons and lacustrine depsits derived relative to the orogen, for example, island arc, back-arc, from them include Paleogene Kamloops Group transten- ocean basin or continent-margin foredeepclastic wedge or sional arc volcanics (PTK) and Neogene Chilcotinback-am passive-margin sediment, and so forth. Tectonic assem- volcanics (NTC). Locally Neogene Fraser alluvial sedi- blages are commonly namedafter their principal constituent ments are exposed through a regionally wider;pread cover formation, groupor region in whichthe assemblage is best of Quaternary deposits (Q). described. Intrusive rocks in Quesnelliainclude pre.accretionary The tectonic assemblage mapsof Tipper ef al. (1981) and accretionary Early Jurassic plutonsand al!.o some mid- andWheelerandMcFeely(199l)outlinethevariousassem- Cretaceouspost-accretionary stocks (\l'heelcr and blages of the Canadian Cordillera. The Quesnel Lake por- McFeely, 1991, Armstrong, 1988 and Woodrworth et al., tion ofthe maps shows thefour main tectonic assemblages 1991).Ear?yJurassicintrusions(214-182Ma) includeboth in the project area as illustrated by Figure 2-2. The assem- calkalkaline plutonsthat are equatedwith intzusionsof the blage namesand mnemonic codes used in the figure and in Guichon Creek batholith(ElgG) as well as hij:h-levelalka- the following discussionare those of Wheeler and McFeely line stocks similar to the Copper Mountainsuite (EJyCM). (1991). The principal assemblage in Quesnellia, the pre- Some other unclassified intrusions form suites of dioritic dominant unit in the project area, is the Triassic-Jurassic @Id) and granodioritic(Elg) stocks. Post-ac~:retiomary in- Nicola island arc - marginal basin sequence (TJN). The trusions (130 - 87 Ma) are equivalentto the Bayonne granitic underlying rocks are the Crooked amphibolite, partof the suite (mKgB) as wellas some additional unclassified gra- Slide Mountain assemblage(DTS), a mylonitized mafic and nodioriticintrusions(mKg).Tertiaryplutonicrocksbavenot ultramafic unit of oceanic marginal basin volcanic and been discovered in the projectarea. although Kbceni: alkalic sedimentary rocks. The Barkerville Subterraneto the east, volcanic rocks and lamprophyric dikes are kuown'LO occur a continental prism sequence,is made np of two units,the (this study). Snowshoe Group (PP) and Quesnel Lake gneiss @MqQ). The terminology used for the Mesozoic: volcanic arc The Snowshoerocks are Hadrynian (Upper Proterozoic) to rocks in Quesnellia has been inconsistent. It has created Upper Devonian metasediments that ax considered to be dificulties in correlating the rocks in the cmtral Quesnel wrrelative in age with Eagle Bay rocks (PPEK) of the Trough with similar rocks in other areas, even though all adjoining Kootenay Terraneto the south. The Quesnel Lake these rocks occur in the same terrane. The rocks in the gneiss, found locally near Quesnel Lake within regions of project area have, at various times, been given their own predominantly Snowshoerocks,isaDevonian toMississip- group names, for example, Quesnel River Group (Tipper,

" Bulletin 97 9 1959,1978; Campbell, 1978)and Horsefly Group(Moaoa (quartzose) schist, micaceous quartzite, feldspathic schist, 1976). The volcanicarc mks have been commonly referredmetasiltite and phyllite with lesser grit, calcareous phyllite, to as Nicola Groupbecause of their similaritywith rocks to micritic limestone, marble, calcsilicate, amphibolite and the south (Bailey, 1978; Bloodgood, 1990). Alternatively, amphiboliticgneiss (McMullin, 1990).The rocks resemble, comparisons withsimilar rocks and stratigraphyto the north in pan, the Paleozoic Eagle Bay assemblageof the Adam permit a valid correlation with the Takla Group (Zpper, Plateau - Clearwater area (Schiarizza and Preto, 1987) and 1978; Rees, 1987).Much recent work in the northern Ques- have also been correlated withthe Lower Paleozoic Lardeau ne1 trough refers to the Triassic-Jurassic arc assemblages Group and the Carboniferous Milford Group of the there as Takla, for example, Nelson and Bellefontaine, Kootenay Arc (Struik, 1986). (1995) and Femi et nl. (1992). Comparisons can also be Quesnel Lake gneiss (DMqQ) forms tabular to sill-like made with the similar but somewhat younger rocks near (Fletcher, 1972) intrusive bodies generally about 2 to 4 Rossland in southern Quesnellia, referredto as the Rossland kilometres in widthand up to 60 kilometreslong Group (Hay and Andrew, 1988). (Montgomery, 1985; Rees, 1987).Anumber of bodies ofthe Nomenclature applied in the Quesnel Lake areafrom megacrystic quartz-feldspar augen gneiss have been 1971 to 1990 by various workers has been summarized by mapped adjacent to the Barkerville- Quesnel terrane bound- McMullin (1990, page47). The basal sedimentary unit has ary (Rees, 1987). The gneiss along this boundary hasa well been referred to by the. following terms: pelite;black pelite; developed mylonitic fabric in places and is mechanically graphitic pelite; Quesnel River Group; black phyllite; phyl-intercalated with Crooked amphibolite. Rees recognized lite; black shale, slate, argillite and so forth; graphitic phyl- two major phasesof deformation in this unit. lites and argillites; Eureka quarzite and Crooked Lake Quesnel Lake gneiss shows considerable variation in phyllite; Nicola Group; Quesnel Riveror Nicola Group; and composition from diorite to granite to syenite. ma major Slocan - King Salmon assemblage.The upper, volcanic unit varieties of granitoid orthogneiss withinthe Snowshoe has been referred to as: Quesnel River Group; Horsefly Group metasedimentsare described on the basis of miner- Group; Takla Group;Nicola Group; possibly Takla orNi- alogy and grain size. The. main variety is charactexized by cola Group; Takla- Nicola assemblageand simply ‘volcanic pale outcrops composedof potassium feldspar megacrystic rocks’. Ages are stated to be: Triassic;Upper Triassic; rockswithamafic-poorgroundmassofquartz,feldsparsand Middle. - Upper Triassic; Middle to Upper (?) Triassic; white mica. Four distinctlithologies are described Upper Triassic - Lower Jurassic; Triassic - Jurassic and (Montgomery and Ross, 1989) from the larger intrusive Jurassic. bodies: a micaceous quartz-feldspawhornblende gneiss, a The usage for all the Triassic-Jurassic volcanic arc and pinkish pyroxene-hornblende-feldspar gneiss,and rarer related rocks in Quesnellia currently preferred and advo- dark green amphiboliteand garnetiferous syenitic gneisses. cated (Gabrielse andYorath, 1991; Wheeler and McFeeley, The second type of gneiss is found to the south of Quesnel 1991) is Nicola Group. The term Takla Group possibly Lake. It is a more homogeneous, medium-grained, streaked should be discarded except for informal, regional usagein black-grey-white gneiss to fine-grained schistose rock. It the northern Quesnel Trough. The term Stuhini should be forms a discrete map unit inthe Boss Mountainand Mount reserved for the similar (some would say identical) Triassic- Perseus areas but is thought to berelated to the main gneiss Jurassic, akalic volcanic arc rocks of Stikinia. unit (Mortensenet al., 1987). Ross and co-workers (1985) indicate that emplacement of this orthogneiss preceded or REGIONAL. MAP UNITS AND MAP was contemporaneous with first-phase deformation. PATTERNS The emplacement ageof the gneisses is interpreted to be Late Devonian to middle Mississippian basedon U-Pb BARKERVILLE TERRANE (KOB} dating (Mortensener 01.. 1987). Geochronological datafor all the gneisses in thedistrict have been tabulated by Rees SNOWSHOE GROUP (PP)AND QUESNEL LAKE (1987, pages 36-41). Dates range &om 752 to 106 Ma for GNEISS (DMqQ) various minerals dated by different radiometric methods. Pericratonic pelitic and psammitic metasedimentary The data suggest a long and complex tectonic history for rocks of the Snowshoe Group and intrusive Quesnel Lake Quesnel Lakegneiss with a Late Devonian or early Missis- sippian intrusive age, Middle Jurassic metamorphism and gneiss are exposed in thenorthern and easternparts of the projectarea. Snowshoe rocks are Late Proterozoic later, possibly mid-Cretaceous,igneous resetting. (Hadrynian) to mid-Paleozoic(Devonc-Mississippian ?) in age. The successions consist mainly of moderately to thinly CACHE CREEK TERRANE(CC) interbedded gritty siliciclastic and pelitic metasediments (Struik, 1988a). Metamorphic grade ranges from green- CACHE CREEK GROUP(MTC) schist to amphibolite facies. The rocks are commonly finely Cache Creek rocksare found in only a very small part foliated due tostrong deformation and dynamic recrystalli- of the project area to thewest of Beaver Creek, north and zation, especially nearlithologic contacts and the top of the south of the Likely - Tyee Lake roadjunction @ITS 93N5). unit. Majorlithologies include pelitic to semipelitic The Cache Creek Group is the main assemblage underlying

10 GeoIogical Survey Branch Ministry ofEmployment and Je@ the plateau regionto the west of the Quesnel map area but (Rees,1987),possiblyadisconformity.Wbetherthiscontact is extensively coveredby Tertiarystrata and youngersurf- between Quesnellia rocks and Crookedamphibo:3te is de- cia1 deposits. The older bedrocks are poorly exposed positional (Rees, 1987). smctural (most authors)or uncon- throughthedeepcoverofTertiaryandyoungerrocks.Major formable (McMullin,1990) remains uncertain. For rock exposure consistsof liestone that formsa number of convenience in mapping and map representation, Crooked large bluffs withinan overall poorly exposed succession of amphibolite is generally consideredto be part of C!uesnt:llia Mississippian to Upper Triassic (probably Pennsylvanian and is regarded to be the base of the terrane (Smlik, 1986: andor Permian) argillite, siltstone, chert and greenstone Rees, 1987; Bloodgood, 1990). (Campbell, 1978). The limestone is a grey to pale grey weathering major unit in a Permian and possibly older QUESNELLIA (QUESNEL) TERRANE(QN) succession that includes minor greenstone, chert and argillite. HARPER RANCH SUBTERRANE @TH) The Harper Ranch Group (Monger, 1977) 'or assem- SLIDE MOUNTAIN TERRANE (SM) blage is considered to underlie the Mesozoicstrata of Ques- nellia in southern British Columbia (Read and Okulitch, CROOKED AMPHIBOLITE PART OF DTS) 1977). The Devonian to Permian, possibly arc-related,as- The Crooked amphibolite,a name proposed by Struik semblage consistsof highly folded and faulted clastic and (1985a). forms a thin, recessive map unit that effectively volcaniclastic units and carbonate bodies which include marks the boundary between the Barkerville and Quesnel chert, argillite, basalt and associated ultramaficro :ks (Mon- terranes. The amphibolite in muchof the map area is about ger et aL, 1991). No Harper Ranch rocks are knownto crop 250 metres thick;locally it isonly a few metres in thickness out in the project area; the nearest exposures underlying or discontinuous (Rees, 1987). In the western part of the Nicola rocks are approximately130 kilometres sclutheast of project area it isup to 800 metres thickand in some places, Horsefly, near Kamloops. Similar rocks, possib;y correla- for example, the hinge zone of major foldsto the south of tive with Harper Ranch rocks, underlie the Takla volcanics Quesnel Lake, it reaches 1200 metres in thickness (Carye, in the Lay Range in the northern Quesnelbelt (Nelson. and 1986; Bloodgood, 1987b). Bellefontaine, 1996). The Crooked amphibolite is correlative on the basis of NICOLA GROUP(TJN) a.k.a QUESNEL RIVER, some lithologic similarities and mainly structural position with rocks of the Antler Formation, part the of Slide Moun- HORSEFLY OR TAKLA GROUP tain Group (Campbell, 1971; Campbell,1978). Struik Two fundamental lithostratigraphic subdivisionsof the (1987) considers it to be the sheared and metamorphosed Quesnel Terrane are evident: a basal, domin:mntly fine- equivalent of the Antler Formation and, therefore, Missis- grained metasedimentary unit andan overlying cqominantly sippian to Permian in age. Crooked amphibolite is distin- volcanic arc assemblage (Figure 2-3). The Middleto Late guished fromother metamorphic rocksby its shear fabric, Triassic sedimentary rocks forma broad, continuous map highly suained contacts, mechanical imbrication, mylonitic unit along the northern one-third to one-halfof the Quesnel fabric and abundanceofamphibolite. Rees (1987) describes project area.They also occur ain series of fault blocks along three major (schistose) constituent rock types: greenstone, the southwestern terrane boundary.The observed thickness metagabbro and meta-ultramafite.In the Eureka Peak area of the sedimentary unit is estimated by Rees (1987) to be map units consistof coarse-grained hornblende schist, talc- about 2500 metres: Bloodgood (1990) suggests thicknesses chlorite schist and actinolite schist. Along strike, nonh of of 2500 to4000 metres from her work in theSpanish Lake Quesnel Lake,there are units of mafic metavolcanics,am- and Eureka Peak areas. The overlyingLate Trias ric to :Early phibolite, chlorite schist, serpentinite and ultramaficrocks, Jurassic volcanic rocks occupy the central and southern pillow lavas are present.locally. Chemical analyses are parts of the northwesterly trending belt and #outline the interpreted by Rees to indicate subalkalic tholeiiticcompo- Quesnel magmatic arc. Volcanic deposits overlying eruptive sitions of basalts formedon an oceanfloor. centres inthe central part of the map area arethe in order of If the crooked amphibolite is equivalent to the Antler 6.5 kilometres thick in addition to the 2.5 kilometres of Formation and is part of the Slide Mountain Terrane, it is sedimentary rocks for a total thickness of 9 kilometres separated from the underlying Barkerville Terrane alonga (Rees, 1987). We estimate a thickness of 7 kilometm for thntst fault (Campbell, 1971). The fault, or more generally the sedimentary-volcanicarc succession. a wide zoneof mylonitization, has been termed the Quesnel The basal unit of dominantly blackphyilitic rocks Lake shear zone (Brown and Rees, 1981; Rees, 1987) or overlies Crooked amphibolite along a variably tectonized Eureka thrust(Struik, 1985a). Crooked amphibolite andthe depositional contact or unconformity. Locall); as in the overlying mks of Quesnellia are st~~cturallycoupled and Spanish Lake area, thecontact is folded and imbricated by emplaced tectonicallyonto Barkerville Terrane. The upper a number of thrusts. Bloodgood subdividedthe raonotonous amphibolite contact has been described by various authors metasediment succession of black graphitic phyllites and to be a sedimentary, albeit tectonized, contact. Alternatively slates into nine lithologic subdivisions. Contacts between it isinterpreted, at least locally, to bea depositional contact the lithologic units appearto be gradationalbut *e package

Bulletin 97 11 MAP UNITS

NWk" CWLlla" Anlslan .Lsdlnlsn PENNSYLVANIAN. PERMIAN MISSISSIPPIAN.UPPERTRlASSlC PROTEROZOIC.MlSSlSSlPPlAN

Figure 2-3. Generalized geologicalmap of project area showing stratigraphic subdivisions and major intrusionsof Quesnel Terrane and adjoining tectonic assemblages. is strongly tectonizea internally and not all the units are and more differentiatedfeldspathic rocks and a variety of presentthroughoutthestudy area. At deeperstructurallevels grey, green and purple-maroon-red volcaniclasticlocks de the rocks are moderately to strongly metamorphosed andare rived from them. Volcanic breccias predominate as thick well cleaved with penetrative phyllitic to slaty foliation. lenses of polylithologic subaqueous, shallowwater "slump" More commonly they are weakly metamorphosed and dis-or subaerial debris-flow and possibly laharic deposits. play only a spaced cleavageand widely spaced fracturing. Flows, crystaland crystal-lithictuff, volcanic-source sand- Lithologic variations along saike are of regional extentand stoneandcong1omeratearealsopresent.Thecoarsr:breccias probably reflect changes in sedimentation during evolution grade laterally outward into conglomerate and finer grained of the low-energy, stagnant Quesnel basin, but maybe in volcaniclastic rocks. This sequence and the presence. of part structuraI. There was some volcanic activity during intrusive clasts can be used to outline eruptive volcrmic latest stages of sedimentation. Volcanic rocks and succes- centres. A number of volcanic centres are cored, or are sions with dominantly volcaniclastic components arepre- inferred to be underlain,by high-level intrusivebcdies. 'The sent in some younger parts of the map unit.The ageof this presence of felsic volcanics and polylithologicbraxias with unit, basedmainly on conodonts and some macrofossils,is felsic volcanic and intrusive clasts characterizes this map Middle to Late Triassic (Anisian to Camian and Norian). unit and provides a basis for distinguishing it from the The overlying volcanic rocks outline a northwesterly underlying, less variable basaltic volcanics. trending belt of subaqueous and lesser subaerial volcanic Theage oftheuppervolcanicunit isEarly Jurassic. The rocks 5 to 25 kilometres wide. They were deposited alonga Sinemurian ammonite Badowrin camdensis and bivalve series of coalescing volcanic-intrusive centres that define Weylaoccurextensivelythroughoutthisunit.Ayoimger,late the Quesnel island arc of predominantly alkalic basalts. A Lower Jurassic age is inferred for the upper pats of the grossly consistent stratigraphy is evident throughout the succession by stratigraphic relationships and fmm radio- length of the volcanic belt in the project area. It is very metric dating by Bailey and Archibald (1990) 2nd earlier similar to thatin the northern Quesnel Trough some325 to workers (see radiometric dating, Figure4-3; Appendix F). 425 kilometres to the northwest, describedby Nelson and The Iast volcanic events in the arc depositt:d marmn Bellefontaine (1996). In addition, the alkalic volcanic rocks analciteandolivine-beaxingbasalt.TheserDcksaxeexp~sed are lithologically and petrologically similar to some of the in a limited area that extends fromthe Quesnel River south distinctive Nicola volcanics of southern Quesnellia (Preto, towards Horsefly. The basalt was erupted subaerially and 1977; Mortimer, 1987). forms massive flows that pass upward into vesicular brec- The oldest and most widespread volcanic rocks are ciated flow tops. The age of the rocks is unce:rtain. The alkalic basalts. They are dark green and grey, olivine and distribution and outcrop panern suggestan unccnfomrable pyroxene-bearing flows, pillow basalt, breccia andtuff de- relationship with the underlying Sinemurian volcanicrwks posited in probably relatively deep marine settings. The and an age probably older than the nearby Plimsbachian younger volcanic rocks of this map unit are dark green to sedimentary strata. maroon, rarely vesicular flows, tuff, volcaniclastic sandstone and breccias. Younger and possibly coeval flows SEDIMENTARY OVERLAP UNITS(JHA) include amphibole-bearing and analcite-bearing pyroxene basalt Thepresence of pyroxene basalt flowsand breccia Sedimentary rocks were deposited in a post-volcanic containingeuhedralanalcitephenocrystsupto2centimetres basin that developed along the flanks and panially over- in diameter provides a useful marker unit. Sedimentary lapped the volcanic arc.The predominantly dark gre:y silt- rocks within and mainly nearthe top of the basaltic succes- stones and sandstones are similar tothose of the basal black siunconsistofgenerallythinmembe~ofdarkgreytogreen, phyllite unit but contain syngenetic or diagenetic pyrite, pyroxenerich sandstoneand siltstone, calcareous sandstone suggesting an euxenic depositionalenvironment North of and graded grey to green sandstone. Many of these rocksare Likely these rocks are in fault contact with older voilcanic calcareous and occur together withsmall lenses of massive rocks; elsewhere contacts are not exposed. APliensbachian grey limestone. Limestone also occursas bioclastic matrix age is indicated by fauna from similarrocks to the west of in a reef-derived basalt breccia. Locally,a thin, distinctive the map area. maroon sandstone marks the top of this volcanic unit. Other conglomeraticrocks to the west and south ofthe The basal contact, whereit is exposed on the shore of arc volcanin are characterized by their grey rmd maroon Quesnel Lake, is a depositional contact between the vol- colour, polylithologic character and presence of granitic canicsandthebasinalsediments.Alongthesoutherncontact clasts. This conglomerate and associated thin-bedded silt- near Beaver Creek the volcanics interfingerwith the sedi- stone and sandstone beds overlap both Cache. Creek and ments. Wherethe contact is visible thereis no suggestion of Quesnellia rocks in the northern part ofthe project area and faulting or any type of tectonic disruption.The age at the farther to the south near Granite Mountain ('Xpper, 1978). top of the unit is defined by conodonts and macrofossils and It is also exposed in narrow, fault-bounded blocks and ranges from Camian to Norian. wedges along the westernside of the Quesnel 'Jlongh. This Overlying the main basaltic unit, probably above an unit is Aalenian and possibly Bajocian in age onthe basis angular unconfomity, is an upper volcanic unit of basaltic of (limited) faunal evidence.

Bulletin 97 13 British CoIumbia

Another polylithologic conglomerateforms a thin belt bearing diorite, lesser monzonite and syenite with minor with a sinuous map patternalong the north shore of Quesnel gabbro, pyroxeniteandperidotite; syenite with megacrystic Lake and Quesnel River. It consists of well rounded and texture and large oahoclase phenocrysts; and a markedly sorted clasts of numerons lithologies, mainly metamorphic silica-undersaturatedsyenite characterized by modal rocks. The conglomerate has a distinctive orange-weather- nepheline, sanidine and sodic amphibole. All three rock ing carbonate matrix and displays fining-upwards se- groups lack modal quartz and have normative nepheline quences of conglomerate,sandstone and mudstone typical compositions. Anumber of the alkalic stocks host porphyry of fluvial or estuarine environments. A similar rock type copper-gold deposits,for example Mount Polley(Carib- faaher to the south inthe Beaver Creek valley, collectedby Bell), Shiko Lake, Kwun Lake and Cantin Creek. The QR R.B.Campbel1, is said to contain Cretaceous (Albian) pollen (Quesnel River) stock is associated with a significant vol- (H.W. Tipper, written communication, 1993). canic-hosted gold deposit. Radiometricdates indicate Early Jurassic coolingages (see Chapter 4). TERTIARYAND NEOGENE TO QUATERNARY A small number of stocks and dikes of leucocratic COVER ROCKS(PTK, NTC, Q) granodiorite, quartz monzonite andgranite occur in themap area and contain some copper and molybdenum. They are Tertiary rocks are poorly exposed in the region and thought to be equivalent to the Naver plutonic suite to the consist of a variety of intermediateto felsic flows, ash flows, north, on the basis of their similarity in appearance and crystal and lithic tuffs and epiclastic lacustrine beds. They Cretaceous age. unconformably overlie granitic rocks to the southeast of Horsefly and occur ina postulated graben tothe west and north. They overlie or interfinger with sedimentary rocks LITHOLOGIC - STRUCTURAL that are. exposed along the upper reaches of the Horsefly PATTERNS River. The Horsefly River beds comprise a sequence of The synclinal aspect of the Quesnel Trough, rmly a lacustrine, varved, flaggy, pale-coloured he-pined tuf- trough in both a depositional and structural sense, is dem- faceous mudstones and clayey siltstones in which Eocene onstrated by thebasal sedimentary unit.In the east the rocks fossil fish have been found CApllson, 1976, 1977% b). Ra- dip and face southwesterly overall, and in thewest they dip diometric datingof the volcanic rocks and pollen fromthe and face or become younger tothe northeast The general sediments determine a Middle Eoceneage for this unit. structural model evidentfor the Quesnel Troughis that ofa A discrete unit of alkali plateau basalt subaerialflows covers some of the map area. The basalts appear to be SW NE depositedoverpartsoftheplateanregionbothasathincover at a present elevation of850 metres and as local valley-fill deposits near Horsefly River and Beaver Creek Theflows locally overlie a thin unit of palagonitic (bentonitic) tephra, breccia and conglomerate. A number of the valley-fill de posits cover fluvial and channel-gravel deposits.A Middle Miocene age isdetermined for most ofthe flow units butthe presenceofyoungerflowsisdocumentedbydetailedstudies and radiometric dating (Mathews,1989). INTRUSIVE SUITES (EJgG, EJyCM, EJd, EJg, mKgB, mKg) lbointrusive suites are represented in the study area, those associated with Early Jurassic volcanism and those related to a period of younger, probablyCretamus magmatism The older intrusions, with the exception of the quartz- bearing rocks of the large Takomkane batholith south of Homfly, are generally small stocks of alkalic composition and are. devoid of modal quartz. They mainly form small high-level intrusive bodies that are emplaced at approxi- I I mately 9 to 13 kilometre intervals along the axis of the Figure 24. Generalized cross-sections showingstructural styles volcanic arc. They represent subvolcanic intrusions formed along the Quesnellia-Barkerville terrane boundary. Schematicfor in, ornear, eruptive centres.Afew intrusionsof varioussizes the Spanish Lake area (a) after Rees (1987), and for the Eureka and diorite to syencdiorite composition also occur in the Peak area @) &r Bloodgood (1987). VIew to the northwest;see Figure 2-3 for locations. PP Snowshoe Group, DMqQ Quesnel basal sedimentaryrocks in the northern part of the map area. Lakegneiss, DTS Crookedamphibolite, TJNv Nicola Group The alkalic rocks are subdivided accordingto compo- volcanics,THNms Nicoia Group metasedimentary rocks, FJ sition and textureinto three groups: a dominant pyroxene- intrusive rocks.

14 Geological Survey Bmnch Minktry of Employmen2 and IIEE synclinorium with tightly foldedrocks at deeper structural south, nearEureka Peak, by Blocdgood (1990, Figure 2-4). levels having welldeveloped penetrative cleavage. Upper They describelarge-scale, second phase, Jurassicfold stn~c- parts display open,upright folds with less well developed tures of the Quesnel belt sedimentary units and Crookd cleavage. In the uppermost, volcanic portion of the belt, amphibolite structurally coupled together with Snowshoe compression and deformation in the structurally massive metamorphic rocks that outline the regional map panem. volcanic units is accommodated by block faulting. In the Eureka Peak area the folds range from upright to Regional mapunit contacts and structural trends are overturned and recurnbant structuresand tend tobe isoclinal outlinedbythemajortectonicconractalongtheBarkerville- to tight at depth and more open at higher structural levels. Quesnellia terrane boundarymarked bythe Crooked amphi- In the Spanish Lake area large second phase fol3s define bolite. The structural patterns to the north, near Spanish recumbant, southwesterly verging structureswith compli- Lake, are shown schematically by Rees (1987) and to the cated map patterns. .~~ ......

Britbh Columbia

16 Geohgical Survey Branch Ministry of Employment and In

CHAPTER 3 GEOLOGY OF THE

CENTRAL QUESNELBE:LT~

MAP UNIT LITHOLOGIES AND whatfarther to thenorth in the UslikaLake area (Fem el d., 1992). STRATIGRAPHY The geometric defintion of the Quesnel Trough is The Quesnel belt consists of two fundamental elements provided by Unit 1- the basin411 rocks commonly referred - a basal fme-grained sedimentary unit that represents a to as the ‘black phyllite unit’. In the eastern part of the map basin-fill succession (UnitI) and an overlying volcanicarc area the rocks dip toward the southwest;in the wwem part, subaqueous to lesser subaerial assemblage (Units 2,3 and they dip to the northeast. This Middle to Late Triassic 4) (Figure 3-1). The sedimentary-volcanic arc succession succession has been subdivided into nine map units and has been estimated to have a thickness of 7 or 9 kilometres described in detail by BloOagoOa (1990). In this repit eight (Bailey, 1978 andRees, 1987, respectively). This two-fold ofher subunits areincludedinunit 1; theninthisconsidered lithologic distinctionof major map units corresponds tothe to be equivalent to unit 1A - a volcanic and volc;miclWiC (sedimentary) Rainbow Creek - Inzana Lake Formations unit within the upperpart of the basin-fill succession.These and (volcanic) Witch Lake - Chuchi Lake Formations of clastic rocks are weakly metamorphosed and weakly to Nelson etal. (1991) andNelson andBellefontaine(in prepa- strongly deformedat deeper structural levels. ration) in the Mount Milligan - Nation Lakes areas of the The main Late Triassic to Early 3urassic volcanic as- northern Quesnel Trough(NTS 93K, 93N). The same two- semblage occupiesthe central, northwesterly trending elon- fold sedimentary-volcanic distinctionis also evident some- gate axis of the volcanic-sedimentary belt. It comprises

Bulletin Map units Lithologies Age 0 Qal QUATERNARY NTC 11,lla olivine basalt; conglomerate TERTIARY PTK 10.10a sandstone, mudstone: ash tuff cobbleconglomerate, sandstone UPPERJURASSIC/CRETACEOUEi? JHA 9 f aranodiorite.ouartz monzonite JURASSIC diorite, monzonite, syenite 208 182 Ma WAr EJ,mK 7,8 granodiorite - JHA 5,6 siltstone, sandstone, conglomerate: Toarcian? Aalenian andesite 4 amygdaloidal olivine basalt Pliensbachian polylithic breccia, flows 3 lahar, tuff, sandstone Sinemurian sandstone, siltstone, limestone; ?.I plagioclase p roxene basalt TRIASSIC TJN 2e analate p roxeneiasalt 26 pyroxeneiornblende basalt 2c polylithic breccia 2b basalt - breccia, tuff, sandstone 2a alkali olivine basalt Norian wacke Carnian la pyroxene basalt 1 sandstone. siltstone. shale Anisian - Ladinian phyllite DTS & Crooked amphibolite PENNSYLVANIAN - PERMIAN DTH 1)Harper Ranch DEVONIAN - PERMIAN Quesnel Lake gneiss PP Snowshoe PROTEROZOIC - MISSISSIPPIAN L Figure 3-1. Schematic stratigraphic section showing lithologiesand ages of map units described in Quesnel Troughprcject area.

BuIletin 97 17 MAP UNITS

JHA

Figure 3-2. Generalized geological map of the Quesnel Trough project wea showing unils 1 and la - metasedimentary rocks......

Ministy Employmem and Investment of "

are listed in Chapter 1 in the section dealingwit1 previous I Eureka Peak work. SEDlMENTARY BASIN FILL, BACK-AIRC OR MARGINAL BASIN DEPOSITS - UNITS 1 AND la We consider all Mesozoic sedimentaryunits that overlie the Crooked amphiboliteand that underlie or interfinger with the Quesnelarc volcanics to be partof unit I. Spafially restrictedvolcanic deposits and proximalvolcaniclastic components derived from them occur near the top, but within unit 1 are shownas unit la. The nine subdivisionsof our unit 1 are shown by Bloodgood (1990)as units Tral to Tra6, Trb, Trc and Trd. Our volcanic and volcan,slastie unit la includes Bloodgood's units TrJa, TrJb, probablyTn: and possibly even some or all the volcanic memlars in the Eureka Peak area of her unit Trb. Her (volcanic:] units TrJa and TrJbin the Spanish Peak area are included in our unit 2abutthevolcanicportionofherunitTrbmaybeequivalent I 1 to our unit la. Figure 3-3. Schematic seetion and stratigraphic subdivisionsafter Bloodgood (1990) illustrate correlations between the EurekaPeak and Spanish Lake areas. Unit designations outside stratigraphic METASEDIMENTARY ROCKS (PHYLLITES) - columns correspondto map units in this report. UNIT 1 The stratigraphic succession and mapunifi; described by Bloodgood(1990, pages 6-11) are described below. The three main map units - a main volcanicediface of basaltic sedimentary units collectively constitute unit 1 of this re- flows, breccia and flanking volcanic-source detritus(unit2). port; her volcanic membersare part of our map units la or an upper, more differentiated pyroclastic and volcaniclastic 2a, as discussed above (Figures3-1.3-2 and 3-2.). unit (unit 3), and a small flow unit of subaerial basalt (unit 4). The volcanic-sedimentary arc rocks are overlain by UNIT Td-MICACEOUS QUARTZITE various successionsof late Early Jurassicrocks (units 5 and 6)and younger, possibly Cretaceous,coarse. clastic deposits This is the basal unit of the metasedimenfary a?,sem- (unit 9). Subvolcanic alkalic intrusiverocks (unit 7) that are blage that overlies Crooked amphibolite. The micacwus coeval with the youngest periodsof arc volcanism intrude quartzite implies thatthe rocks are continent-margin depos- along the medial axis of the volcanic belt. Other cogenetic its rather than deepOcean basin fill or fore-arc deposits. intrusions appear to be emplaced at deeper levels and are The unit crops outalong the limbs of the Eureka Peak exposed to the east of the volcanic belt inthe sedimentary syncline. It varies in thicknessfrom 10 to 150mt:tres, either rocks of the basal clastic unit. A few quam-bearing Early as a result of sedimentary depositionorsmcturd. thickening Jurassic (unit 7A) and Cretaceous (unit8) intrusive bodies due to imbrication and/or folding. Bedding is well defined are also present in the map area. Tertiary volcanic and by pale grey, laminated quartzite beds 0.5 to 6 :entimetres sediientaxy rocks (units 10 and 11) cover muchof the map thick. A bedding-parallel schistosity is defined by planar ma. Quaternary cover is extensive, mainly as lodgement alignment of rustyweathering muscovite.The contact of the till, ablation moraine and fluvioglacialdeposits (unit Qal). micaceous quartzite with the underlying Crookedamphibo- The map unitsof the Triassic -Jurassic Quesnel Trough lite issharp, although both concordantand discordant rela- and the overlying youngerrocks are discussed in =me detailtionships havebeen documented. The contact is imbricated below. Lithologic descriptions are, in large part, summariesnear Crooked Lake. No correlative unit has been recognized of the extensive petrologic descriptions, chemicalanalyses in the Spanish Lake area. and modal and normative determinationsof Morton(1976) and Bailey(1978). Generalized distributions of the11 bed- UNIT Tra2 - MICACEOUS BLACK PHYLLITE rockunits are illustratedon Figures 3-2to 3-8 and3-10, and AND TUFF shown in detailon the accompanying 1:IOO OOO map (Map Siliceous dark grey to black, graphitic phyrlite has a 1, in pocket). Theolder rocks of the neighbouring Crooked well developed phylliticfoliation withcharactelistic silvery amphibolite and adjacent terranes were not studiedin the fresh surfaces. Beddingis rarely seen. Where present it is course. of this project and are not discussed in any fuaher defined by thin,rusty to dark grey quartzite or siltstone beds detail. The extensive studies by other authors of these and up to 20 centimetres in thickness and discontinuous tuf- the metamorphic rocks of the adjacent Barkerville terrane faceous lenses. SmalI porphyroblastsof chalky weathering

" Bulktin 97 19 MAP UNITS

CBl"la" Anlslan-Ladlnian PENNSYLVANIAN-PERMIAN DEVONIAN. PERMIAN

PROTEROZOIC.MlSSlSSlPPlAN

12103

Figure 3-4. Generalized geological map showing unit 2 - basal&. MAP UNITS

NO#*" Camla" Mlolan .LadinIan PENNSYLVANIAN. PERMIAN DEVONIAN-PERMIAN

PROTEROZOIC. MISSISSIPPIAN

Figure 3-5.Generalized geological map showing unit3 - 'felsic breccia'. MAP UNITS

Figure 3-6.Generalized geologicalmap showing unit 4 - subaerial basalt. MAP UNITS

Figure 3-7.Generalized geological map showing units 5.6 and 9 - overlap units. MAP UNITS

12iw

Figure 3.8. Generalized geological map showing units 10 and 11 - Tertiary rocks. ~ ~~ ~~

Ministy of Employment am'Investment

plagioclase occur throughout the unit. On the south limb of and an upper succession of graphitic phyllite. Then: are the Eureka Peak syncline porphyroblastsof garnet up 0.5to minor interbedded quartz sandstone and limestone beds. centimetre in size are abundant within10 metres of the base Bedding is defined invariablyby prominent pale.. laminated of the unit. The contact with the underlying micaceous quartz siltstone beds that rarely exceed 2 cemimetres in quarzite is not exposed but maybe faulted, judging from the thickness. The rocks are exposed south of HomeflyLake, noticeable break in slope and the discordant contact rela- on the south limbof the Eureka Peak synclineald in :small tionship ObSeNed on the north limb of the Eureka Peak synclinal cores north of Spanish Lake. syncline.NolithologidequivalenttothisunitintheEureka Peak area has been recognizedin the Spanish Lake area. UNIT Trb - BANDED SLATESAND TUFF!; Unit Trb,the uppermost phylliticunit in the metasedi- UNIT Tra3 - PEYLLITIC SILTSTONE mentary succession,contains a significant volcanic compo- This unit contains interbedded paleto dark grey silty nent. Where volcanicrocks, or their eroded prodllcts, the are slates and lesser phyllitic siltstoneand minor siliceous lime- dominant lithology,the successions are included in unit la stone. Beddingis well defined byfine banding, thinbeds of in this study. Unit Trb cropsout continuously along boththe laminated quartz sandstone and minor interbeds of siliceousnorthern and southern limbs of the Eureka Peak syncline, limestone. Well-developed cleavageis defined by a planar, and underlies much of the westernof part the basalsedimen- slaty parting. Narrow bedding-parallel quartz veinlets occurtary belt along Horsefly River, between Horsefly and Ques- throughout. This unit has not been recognized outside the ne1 lakes and northwest of Quesnel Lake.The contact with Eureka Peak area. the underlying rocks, at least locally in the mea north of Quesnel Lake,is interpreted tobe a fault. UNIT Tm4 -LAMINATED PHYLLITEAND In the Eureka Peak- Horsefly River area, and probably PORPHYROBLASTIC PHYLLITE generally throughoutthe belt, there is aprogressiveincrease Finely laminated grey phylliteis intergradational with in volcanic componentsat higher stratigraphic levels this in the underlying and overlying units. Bedding is outlinedby unit. Dark green to black phyllite withinterbettdedgrey to pale grey to rusty weathering quartz sandstone beds com- green tuffs comprise the lowermost50 metres olthe succes- monly 1to 3 millimetres but upto 1centimetre in thickness. sion. Siliceous, banded aquagenetuffs become more abun- A welldeveloped phyllitic foliation is accentuated by gra- dant stratigraphically upwards and are intertdded with phitic material. Porphyroblasu of garnet, plagioclase and grey to black banded slates, massive pale quariz sandstone chloritoid occur in these rocks on the south limb of the and minor limestone.Theuppermost part ofthe unit consists Eureka Peak syncline; chloritoidis associated with ankerite of fissile graphitic phyllites interbedded with tuffs, and on the north limb. Bedding-parallel quartz lenses, up to 2 locally with dark brownto black argillaceous limestoneand metres in thickness and severalmetres in length, are present. minor quartzose sandstonebeds. The phyllite; within this They are most evident along the north libof the Eureka section are recessive, black and sooty in outcrop. Imally Peak syncline, most notably thein Frasergold property area. they are strongly silicified, but throughout the region they No stratigraphicallyequivalent units have been recognized are typically rusty weathering and pyritiferous. in the Spanish Lake area. North of Quesnel Lake, thein Spanish Lakearea, black sIaty to phyllitic, rusty weatheringmetsediients an: inter- UNIT Tra5 -SILTY SLATES bedded with gritty, dark brown to black-weathering grey limestone. Conodonts fromthe limestone are Middle Trias- The porphyroblastic phylliteunit (Tra4) grades upward sic in age (Anisian to Ladinian); eastof Spanish Mountain into coarser grained, dark grey to black-weathering silty the rocks have yielded conodontsof Anisian ;miprobable slates with interbeddeddark grey quartzose sandstone.Bed- Anisianage(GSCLocationsC-117649andC-11764.5,M.J. ding is shown by dark grey, dullquartz sandstonebeds, most Orchard, analyst). Struik (1986, 1988a) has snggested that commonly 10 to 12 centimetres in thickness. Thinner, pale imbricationhastakenplacewithinthismapunit,onthebasis layers of laminated quartz sandstone are interbedded of these conodont ages. throughout the unit. Pale weathering quartziteand pale grey The volcanic component includes discontinuous lenses to green-weathering tuffs form discontinuous lenses. Silty of banded tuff, volcanic conglomerate, flow breccia, pillow slates have well developed planar slaty parting.In outcrop lava and a few dikes. The banded tuffs in the :Spani:shLake they are wty weathering to locally speckled with limonite, area arelithologicallyidentical tothe banded aquagene tuffs probably due to the presence of fine-grained siderite or in the Eureka Peak area but the Spanish Lake succession authigenic iron sulphide minerals. These rocks are the basal also includes volcanic conglomerate, breccia and flows as map unit and the dominant rock type in the Spanish Lake discontinous lenses toup several kilometresin strikclength. area. The volcanic rocks appear tobe identical to the pyroxene- bearing flowsof the overlying, volcanic unit in the Eureka UNIT Tm6 - GRAPHITIC BLACK PHYLLITES Peak area and in the mainQuesnel volcanicbdt to tlne south This unit formsa sequence of grey, graphitic phyllites and west. The volcanic rocks in unit Trcare now known to that gradeupward through blackphyllite, grey siltyphyllites be chemically distinct from the main volcanic arc racks (see

Bulletin 97 25 .. .~...

British Colrunbia

Chapter 5 -Petrochemistry). Theyare now consideredto be characterized by a brecciated mbbly base, homogeneous, a discrete subunit within the sedimentary succession, re- massive centre and coarser porpbyryitic top. Outcrops are ferred to in this study as unit la. pale green to grey but commonly are. sty weathering and crumbly or yellowish green in areas of extensive epidote UNIT Trc - VOLCANICLASTIC BRECCIA alteration. The coarser porphyritic flows contain black and green mafic phenocrysts, commonly 2 to 5 millimetres in breccia unit crops out to the west of Eureka Peak This size but up to2 centimetres in length.. The pyroxene crystals where it overlies the sequence of unit Trb. It tuff-phyllite are stubby, subhedral and extensively altered to chlorite. consists of darkgrey, angular clasts in a paler grey matrix. Amphibole crystals euhedral, acicular to prismatic in chloritization is extensive and readily evidentin a cleavage are form, and little altered. defmed by well developedchloritic patting. Both the lower and uppercontacts with unit Trb and the overlying volcanics VOLCANIC AND EPICLASTIC ROCKS- are faults. We consider this unitto be an iutraformational breccia, asfmt suggested by Campbell (1971), and partof UNIT la unit la. Hornblende pyroxene basaltflows, breccia, related volcaniclastic deposits and conglomerate comprise this UNIT Trd - VOLCANIC SANDSTONEAND subunit. Pyroxene-bearing hornblende porphyry members WACKE also form small intrusive bodies and inmsive breccias within it of Quesnel Lake unit Trb is overlain by this unit Noah Unit la has been defined (this study) as a discrete of coarse-grained, dark green volcanic sandstonesand volcanic subunit withinthe predominantly sedimentary unit wackes with interbedded siltstone, sandstone and minor 1. It is found at Horn Bluffon Horsefly Lake and in the thin argillite. The argillaceous sedimentsare interbedded in beds belt of volcanic rocks between Horsefly Lakeand Quesnel 3 milliitres to 2 centimetres thiik with dominant green Lake, centred around Vlewland Mountain.There unit la on sandstone and wacke and give rise to a compositionally the east side of the volcanic beltis incontact with sedimen- defined. colour-banded sequence, parallel to bedding. A tary rocks of unit 1 along a steeply eastward-dippingreverse rough fracture cleavage parallel to the bedding is locally fault. Unit la includes rocks of Bloodgood‘sunits TIC, TrJa developed but no penetrative cleavage is recognized. and Tdb from the volcanic klippe in the Eureka Peak area, discussed above, and possiblyher unit Trd in the Spanish UNITS TrJa AND TrJb -MASSIVE FLOWS, Lake area. The volcanicrocks of unit la are not considered AGGLOMERATE, TUFFS, PILLOW BASALTS to be part of the overlying unit 2 because these volcanic AND MAFIC DIKES; MASSIVE PORPHYRIlTIC rocks form a succession near the top, but entirely within, FLOWS, BRECCIA TUFF AND sedimentary unit 1. Mapping in the Viewland Peak area A succession of matic volcanic rocks 300 metres thick, reveals that the apron of volcaniclasticrocks and conglom- referred to as ‘Nicola Group metavolcanics’ by Bloodgood erate that surrounds the pyroxene amphibole basalt inter- (1990). forms a klippe that occupies the core of the Eureka fingers with the sedimentary rocks of unit 1. In addition, Peak syncline. She correlated these rocks with the pyroxene- petrochemical differencesare evident between the volcanic bearing volcanicsof unit 2, but we now regard themas part rocks of units la and 2. The chemicaldistinctions offer the of unit la, largely on the basis of their petrology and chemi- most persuasive evidence for subdividing these volcanic cal compositions, as described in Chapter 5. units, as discussed in Chapter5. Northwest of Likely to the Lithologies described by Bloodgood (1990) in the Cottonwood River, unit 1has not been subdivided, although Eureka Peak area .include crystal-lithic tuff,basalt pillow Bailey (1978, 1990) noted that volcaniclastic sandstone, lava, flows, flow breccia and volcanic breccia and minor conglomerate and basaltic breccia are locally dominant limestone. Thetuffs form the basal member of the volcanic lithologies near the top of the sedimentary succession. sequence 5 to 20 metres thick, but locally they attain a Petrologic descriptions by Bloodgood (1987a) of vol- thickness of up to50 metres. The tuff forms massive, homo- canic rocks in the Eureka Peakarea offer moredetail about geneous, rarely banded, palegrey to green-buff-weathering primary and metamorphic mineralogy. She describes the ontcmps. Volcanic lithic clasts and mafic epidotechlorite- volcanic rocks to consist of primary phenocrysts clinopy- altered crystals up to 3 millinem in size are contained in roxene, hornblende and plagioclase witha groundmass of a fine-pined matrix. pyrite cubes up to 1centimetre across similar composition and tremolibdactinolite, clinozoisite, havebeenobservedandmillimetre-sizedcubesarecommon epidote, sericite,chlorite, biotite, carbonate and quartz, innarrowpyriticbeds.Annitofpillowbasaltupto10metres some of which is a metamorphic or alteration assemblage. thickoverliesthetuff.Thepillow1avasarepalegreytogreen The clinopyroxene, withor without hornblende,is the domi- weatheling but dark on fresh surfaces. Pillow structnres are nant phenocrysttype in thebasal part of the volcanic assem- flattened with dimensions of 60 by 30 by 60 centimetres. A blage; amphibole is more abundant in the higher thick sequenceof porphyritic basaltflows, flow breccias and stratigraphicunits. The mafic miuerals comprise from 20 to volcanic breccias forms the main part ofthe volcanic unit. 50% of the rocks. Plagioclase, both as phenocrysts and Individual flow units are 15 to 30 metres thick and are groundmass, accounts for up to35% of the rock but varies

26 Geological Survey Branch Ministry of Employment ml Znvesmtmt in abundance proportionallywith hornblende. Clinopy- (1978)estimatesathicknessof3100metresforthevolcanic roxene phenocrysts are dominantly euhedral to subhedral succession. The units establiihed are: and vary in size from 0.01 to 3 milliietres. Hornblende 2a - Green and grey pyroxene-phyric alkali chine occurs as euhedral to subhedml, twinned, tabular crystals and alkali basalt flows, breccia, minor pillow basalt from less than 1 millimetre to 1 centimetre in size. Plagic- 2b - Grey and maroon pyroxene-phyric alkali basalt clase is variably saussuritized, but where compositions can flows and breccia, minor basaltic tuff and maroon be determined, it isandesine, approximatelyAw. ’bin- sandstone ning is generally preserved with common albite and less 2c Polylithic grey and maroon maficb~eccia common Carsbad twinning. Mafic grains are commonly - rimmed by actinolite and biotiteor completely replacedby 2d - Greenish grey and maroon hornblende-bearing chlorite and calcite. Accessory minemls include apatite, pyroxene basalt sphene and opaque minerals. The flow textures are hypidio- 2e - Greenishgrey and maroon anal&4earing morphic granular to glomeroporphyritic and variably pyroxene basalt flows,breccia and mincrtuffti vesicular. 2f - Dark grey to brown maficsiltstone. sandstone, Pyroxene-bearing hornblende porphyry dikesand sub- calcareous sandstone;grey limestone and limestone volcanic syenodiorite breccia cap the peak of Vlewland breccia; grey to greenish grey sandstone Mountain. The porphyries, together witha number of small plugs, indicate the region was thesite of subvolcanic intru- Each map unit has oneor more dominant rock types; sive activity in the Quesnel sedimentary basin during peri- photomicrographs ofthe typical rocks are shown on Photos ods of early volcanism. 3-3, and3-4. The appearanceof outcrops and rock fabric is shown on Photo 3-4. Phencocrysts of diopsidic augite composition are characteristicof all the basalts and tile pyroxene VOLCANIC SUCCESSIONS OF THE displays very little compositionalvariation tetween the QUESNEL ARC units (AppendixA). The rock types as described mainly by Morton (1976) and Bailey (1978)are as follows: The volcanic deposits of the Quesnel belt island arc succession are subdivided into three major map units (units ALKALI OLIVINE PYROXENEBASALT 2.3 and 4).The two most voluminous volcanic assemblages, (UNIT 2a) units 2 and 3, are funher broken down into subunits. Al- though the volcanic rocks generally form lithologically This basalt overlies or interfingers with redimentary similar prisms, wedgesor lens-lie deposits, a stratigraphic rocks of unit 1and forms sequencesof massive IO brecciated succession can be resolved mainly fromthe superposition flows and lesser pillow basalt.The flow rocks are m,assive of units,some paleontological data (discussed inthe follow- aphaniticto porphyritic, commonly with brecciated, ing chapter) and radiometric dating of crosscutting intru- amygdaloidal tops. Theyare interbedded with ltasaltic clas- sions. The present subdivisionsare similar to those defined tic rocks, mudstone, calcarms mudstone and limestone by Bailey (1978). They extensively revise and largely in- lenses and breccia. validate the stratigraphy used by Morton (1976).In general, Phenocrysts andother grains discernible by eye make the volcanic succession consistsof subaqueous pyroxene- up from30 to 75% of the rock and comprise c1inopy:roxene phyric basalt flows and breccias (unit 2), an overlying (diopsidic augite), olivine,plagioclaseand magnetite. Aver- sequence of pyroclastic and debris-flow (laharic?) deposits age phenocryst content of typical rocks is 30% clinopy- (unit 3) and an upper unit of subaerial analcite-bearing roxene, I to 8% olivine, 20% plagioclaseand I to 4% olivine basalt flows (unit 4). Shallow-water sedimentary magnetite. The amounts andgrain size of plagjoclase phe- rocks (parts ofunits 2 and 3) overlap andflank the volcanic nocrysts vary widely between 5 and 40%; most of the accnmulations. plagioclase is contained in the matrix as microlites. The matrix contains small grains of plagioclase :md dinopy- BASALTS UNIT2 roxene, devitrified glass and lesser olivine, magnetite and - accessory apatite,calcite and alteration minemls. This major map unit (Figure 3-4) is made up of a The clinopyroxene is green diopsidic augite.It isgen- succession of alkali olivine basalt, alkali basalt, hornblende- erally euhedral, between2 and 10 millimetre!: and ‘up to 1 bearing basalt and analcite-karing units in the upper part Centimeke long, but with considerable variation in size. of the assemblage. The volcanic rocks are typically dark- Pyroxene grains commonly display simple twinning and coloured, clinopyroxene-phyric basalts in which the flows optical zoning but little compositional variativm. Analyses near the base of the succession contain olivine and those ofpyroxene (Bailey, 1978; Appendix A)indicatean average near the top have analcite. The map units canbe followed composition of ~ao.9~g,FeO)o.g(~,Si)zO6.The py- throughout the length of the central Quesnel belt. Major roxenes have constantcalcium content, relatively high alu- variations in appearance are due to differences in deposi- mina between 4 and 5% and an average magnzsiumto iron tional environments, rock textures and fabric in the ratio in molecular percent Mg:Fe of 3.3:l. Glivinc! grains subaqueous, mainly flow and breccia deposits. Bailey average 0.5 millimetre in diameter but some grains and

” Bulletin 97 27 .. ..~ . .. . ~ . .~

British Columbia aggregates are 2 to 7 millimetres in size and occasionally sidic augite. The rocks form flow and breccia units along reach 2 centimetres. The olivine crystals, now waxy green the eastern side of the volcanic belt near the Quesnel River. pseudomorphs, are recognized by their relict,euhedral In these rocks 5 to 10% hornblende forms euhedral grains shape. They are now virtually all compeletely replacedby up to 3 millimetres in length. Plagioclase occurs as grains chlorite, serpentine, carbonate, magnetite, iddingsite and of roughly similarsize and abundance.Plagioclase compo- other alteration minerals. Plagioclase phenocrystsoccur as sitions range from An54 in crystal cores to An42 near the euhedral laths that are commonly aligned.The plagioclase grain edges. Lmally the unit is predominantly pyroxene is extensively saussuritized but where compositions could grain wacke. be detesmined optically, the plagioclase is labradorite (An50-58)according to Bailey (1978)and An70-75 in cores ANALCITEBEARING PYROXENE BASALT andAn58-65inrimsacwrdingtoMorton(1976).Magnetite (UNIT 2e) is abundant in all the basaltic rocks where it occurs both as Flow and breccia units of darkgreen and maroonanal- an alteration product of olivine and pyroxene and also as cite-bearing pyroxene basaltcrop out in central parts of the discrete, euhedral grains. Grains of magnetite are reported volcanic belt. The green basalts have a characteristic to contain up to 5.5% lQ(Bailey, 1978). Nepheline and coarsely crystalline porphyriticfabric that is emphasized by orthoclase characterize the normative mineralogyof these the presence of large whiteto buff analcite crystals. The rock rocks but only Morton (1976) reports small amounts of has been describedas “bird-dropping rock” because of the modal nepheline in volcanic rocks from the Horsefly area. white splotchy appearance. The phenocrysts make up about 65% of the rock; on average 25% is analcite and the rest is ALKALI (PYROXENE) BASALT (UNIT 2b AND equal amounts of plagioclase and clinopyroxene. In some CLASTS WITHIN UNIT 2c; UNIT 2c) thicker flows,analcite occurs onlyin the upperpart; the base Pyroxene basalts, the most extensive typeof basalt in is pyroxene basalt. The analcites are commonly about 1 the area, axe similar in chemical cornpsition to alkali oli- centimetre across but someexceptional rocks contain crys- vine basalt, but differ by the absence of olivine and the tals up to 3 centimetres in diameter. Some of the larger presence of more abundant modal plagioclase.These rocks analcite grains are petal-shaped, composite aggregates of overlie and inteflhger with alkali olivine basalt of unit 2a. lobate, rounded crystals. Also present are laths of plagio- The rocks form flows, flow breccias and minor tuffs. clase up to 11 millimetres in length andgrains of pyroxene Phenocrysts are mainly pyroxene and plagioclase: the 2 to 3 millimetres insize when equigranular and 5 millime- absence of olivine is characteristic of this rock type. Cli- tres long when present as laths. Feldspar phenocrysts are nopyroxene grains up to 6 millimetm in length comprise generally strongly altered (saussuritizd). In the rare sam- from 10 to 35% ofthe rock; plagioclase (An4z-6~)as tabular ples in which compositions can be determined optically, to lath-shaped, 1 to 4-millimetre crystals forms up to 25%. feldspars appear to rangein composition from bytownite to In some units the plagioclase ~cmas senate, felted trachy- labradorite An77-64 in the early formed, strongly zoned toid microlites that are interstitial to the larger pyroxene largest crystals. In themore abundant and ubiquitous smaller grains. The manix is grey, green and reddish brown and laths, feldspars are labradorite/andesine An54-47.Mi- consists of intergranular to subophitic plagioclase and py- crolites in which compositions couldbe determined froma mxene with accessory magnetite, apatite and patchy altera- few samples from northeast of Horsefly, rangefrom An30 tion assemblagesofhematite, lionite,epidoteand chlorite. to An23 and from Beaver Creek areaAn55 (Coates, 1960). Morton (1976)describes spherulitic textures in amygdaloi- Pyroxene compositions determinedoptically by Coates are dal flows that he interprets indicate the presence ofdevihi- classed as augite in the idiomorphic phenocrysts.In adddi- fied glass. Mortonalso rep%the presence of minor olivine tion, he describes a distinctive grass-green pyroxene in and analcite in the matrix, an observation that was not poikilitic masses of pyroxene-feldspar-iron oxide to be substantiated by this study. aegerine-augiteonthebasisofitsstrongdispersionandlarge Alkalic basalts from mainly unit 2b are the main li- extinction angle. Coates considered this to be a local reac- thologic and compositionalclast type in the overlying brec- tion product @ossibly with seawater). cias of unit 2c. Less wmmon members within unit 2c are Microprobe analyses (Appendix A) suggest typical mafic lapilli tuff, lithic basaltic tuff, pyroxenecrystal wacke diopsidic augite compositions. The pyroxene grains are and tuffaceons wacke. These rocks are part of a maroon to weakly zoned fromcore to rim, with a variation of about3 grey polylithologic breccia unit that is distinguished from mol% in iron offsetby an antithetic decrease in magnesium overlying breccias ofunit 3 by the sparseness or absence of The phenocrysts are contained in a pale grey weathering felsic clasts. homogenous groundmassthat constitutes about 35% of the rock. The marix isaphanitic or composed largelyof plagio- HORNBLENDE PYROXENE BASALT clase microlites and fine-grainedorthoclase, pyroxene and (UNITS 2a/2d AND 2d) magnetite. Accessory and minoralteration minerals include Green and grey basalts near the base of unit 2, possibly apatite, calcite, chlorite, rare biotite and iron oxides. The stratigraphically correlative with units 2a and 2b, contain original presenceof olivine is suggestedby merelict crys- green hornblende phenocrysts in additionto the usual diop tals now replaced by antigorite and iddingsite. Some flows

28 Geological Survey Branch containamygdulesflleded withzeolite(thomsoniteaccording low-temperature subsolidusisotopic exchange With mete to Coates, 1960)and calcite. oric waters)or formed from pre-existing leucite crystals. A second type. of flow unitconsistiof mamon basalt in which the analcites are pink to brown in colour andare both SEDIMENTARYSUCCESSIONS CAPPING UNIT 2 euhedral and rounded. Pyroxene typically occursas small (UNIT 20 phenocrysts or is present in minor amountsas minute grains At the top of unit 2 is a thin successionof sedimentary in thegroundmass. Theserocks also contain analcite in the rocks, unit 2f,a consolidation of three sedimentary subunits groundmass as irregular, interstitial grains together witha termed 2f, 2g and 2hby Bailey (1990). Thc rocks are turbid mass of very fine grained plagioclase microlites and dominantly dark greyto brown mafic, pyroxenwich sand- orthoclase (?), pyroxene, magnetite, calcite. chlorite, stone and siltstone, greenish grey and brown coarsesand- opaque dusty material andother minor alteration products. stone and grey medium-grainedsandstone and siltstone. In In some membes the groundmass is aphanitic and com- places these rocks form flaggy, fetid and pyritiferouu beds monly has the appearanceof devitrified glass. Lithic-crystal containing brokenshells and otherfaunal debri:;. Therocks tuffs with diagnostic pink to brown analcite crystals, and are commonly associated with calcareous siltstoneand mamon to reddish brown laharic deposits with analcite- sandstone and thin, massive micritic and, locally, coarsely bearing clasts,are also present but less common. Flowsare crystalline limestone beds. interbedded locally with analcibbearing coarse breccia A discontinuous unitof the red to maroon basic sand- members, lapilli, crystal-lithic andcrystal-viuic tuffs. stonein the Morehead Lake area, described by Bailey The analcite phenocrysts appear to be a late crystal- (1978), was considered by himto occur at the b~pof unit 2. lizing mineral, whether primaryor secondary is uncertain. The sandstoneis derived from the erosion the of underlying Morton (1976). Bailey (1978) and, before them, Coates basalts and is composed of50% pyroxene grains and pla- (1960) favour a primary origin for the following reasons. gioclase, analcite, magnetite,calcite and clay minerals.This The Phenocrysts, in many cases, are euhedral with sharp rockcontainsTriassic(Norian)fauna.Asandstooeofsimilar composition, but dark green in colour and bearing shell outlines and grain contacts. Euhedral analcite grains are debris of possible Early Jurassic age, is expo!;ed north of present clasts in crystal-vihic and crystal-lithic tuffs.The as Shiko Lake. The rocks there overlain by felsic vc~lcanic white grains isotropic with no twinning evident, al- are are rocks and sedimentary beds with diagnosticEuly Jurassic though pinkcrystals may display some twinning and weak (Sinemurian) fauna. These sedimentary units might well birefringence. Small feldspar and pyroxene inclusionsare form an unconformable successionat the top of the basalt aligned parallel to the trapezohedral faces within analcite unit andthe basal members ofthe overlying, more ox.idized crystals (ocellar texture). Although many analcite-bearing volcaniclastic unit, unit3. flows are amygdaloidal, analcite does not commonly fill The top of unit 2 on the western side of the,central axis vesicles. The crystals and their adjoining grains are not of the Quesnel belt, from near Gavin Laketo south of the cracked or fractured as would be expected if expansion due Quesnel - Barkerville highway,is alsomarked by lenses of to sodium replacement of potassium in primary leucite has discontinuous grey limestone which, on the basis of its taken place. Bailey’s analysis of three analcite samples conodont fauna, is of Norian age (H.W. Tiprer, p:rsonal (Bailey, 1978, page 37 ) reveals no trace of residual K20 communication, 1989). Limestonedoes not appear to have that wouldbe probable if replacement of leucite had taken developed at a similar stratigraphic level to the east of the place. The average of the three chemical determinations, in central axis of the belt. Instead, highly calcareousv’dcani- weight percent, is: Si& - 57.3, AI203 - 23.9 and Na2O - 9.7. clastic sedimenmy rocks occupy this stratigrag hic position. Inmanyrockspyroxenecrystalsarerelativelyunalte~and Bailey (1978) included boththe limestone and the calcare- “fresh-looking”, a most unlikely situationif original leucite ous sediments within unit3 and thus, by inference, consid- has been replaced totally by analcite. All this suggests a eredthem to be of Early Jurassic age. Hcweve.r,later primary origin for the white-weathering, glassy when mapping (Bailey, 1987, 1988) clearly shows these rocks freshly broken, analcite phenocrysts, buta secondary origin form the uppermost partof unit 2 and are Trialisic. for the pink and brown, weakly birefringentgrains and the interstitial groundmass analcite is possible and probably PLAGIOCLASELATH PyRoxEm-Pmmc likely. BASALT (UNIT29, A discussion of analcite in similar Nicola lavas by This isa minor unit inthe Shiko Lake area that clverlies Mortimer (1987) leaves the. problem of their origin unre- pyroxene-rich wackesofprobahleEarly Jurassic age. Itboth solved. This long-standing debate about the primary versus underlies and interfingers with polylithologic: felsic brec- secondary origins of analcite phenocrysts in igneousrocks cias. These rocks were characterized and analyzed as unit has been reviewed (aid perpetuated) by Karlsson and Clay- 2g because of their basalticnature but are probably correla- ton (1991). Their conclusions from stable isotope and mi- tivewithrocksofunit3.Themajorrocktypeisaplagioclase croprobe studiesfavour a secondary origin. Theirdata offer pyroxene basalt withadistinctiveporphyritic taxtureresult- persuasive arguments that despite their euhedral, pristine ing from the presence of large euhedral pyronene crystals appearance, the analcite crystals have undergone extensive and plagioclase laths. About 25%of the rock consistsof 4

Bdtetin 97 29 ~...... ~

Briiish Columbia to 9-millimetre sized euhedral, generally equant clinopy- andesine (accordingtoMorton, 1976) are present. Therocks roxene crystals and 15% is laths of plagioclase 4 to 6 are predominantly breccias deposited as autobrecciated ~ebreslong.Plagioclaseranginginsizefrommicrolites subaqueous slumpand subaerial laharic (debris-flow)units. to 3-millmetrelaths forms an additional 15% of the rock. Flows and pyroclastic breccia andtuff are present but less The presenceof this finer grained plagioclase in the micro- common. The breccias are polylithologic with a wide vari- crystalline to aphanitic groundmass impartsa senate feld- ety ofrocktypes, includingintmiverocks.Thedeposits are spar texture to the overall trachytic-textured rock. The poorly sorted and generally lack stratification. Their pale associated breccias comprise lapilli to ash-tuff sized grey, maroon, red and purplishto violet colour suggests that polylithic clasts. Many ofclasts the appear to be fine-grained they are more oxidized than the underlying basalt units, microdiorite to dioritelmonzonite or latite and are contained consistent with their shallow-waterto partly subaerial ori- in a milled ma& of similar composition. This suggests a gin. The volcanic rocksare flanked by aprons of reworked subvolcanic sourceor flowdome breccia closeto a volcanic breccias, epiclastic sedimentary rocks (wackes) and con- vent. In Beaver Creek valley the predominantly conglom- glomerate derived from the volcanics. eratic rocks of this unit contain abundant feldspathicclasts Compositions of the brecciasvary widely depending on and rare granitic cobbles. Small limestone lenses within thethe composition of the dominantlithic clasts derived from assemblage hold Triassic conodonts. The limestones and the underlying strata and localflows and pyroclastic erup enclosing clastic rocks could be part of an olistostrome and tions. Locally, small amounts of monolithologic trachyticor the map unit might be considerably younger, possibly fme-grained, equigranular and porphyritic breccia and tuff equivalent to unit 3, or even younger, rocks. suggest deposition in and around volcanic dome deposits. Trachytoid latite to trachyte and equigranular, fme-grained POLYLITHIC ‘FELSIC’ BRECCIAS - UNIT 3 dioritetoporphyriticsyenite clasts consistmainly ofplagic- Rocks of unit 3 form a heterogeneous sequence of clase and diopside to diopsidic augite phenocrysts andin- basaltic and intermediate composition (‘felsic’)coarse vol- tergranular orthoclase. Most clasts and the rock matrixare caniclastic rocks, lesser flows and conglomerate.There are generally too altered to optically determine modal mineral- well-defined lenses of sedimentary and tuffaceous rocks ogy and mineral compositions with accuracy. Alteration within the subaqueous shallow-water succession and more minerals are chlorite, epidote, calcite, clay minerals and limited pyroclastic rocks deposited under ephemeral zeolite (laumontite). Whereanalcite is present as an erratic subaerial conditions.The map unit occupies the upper part constituent in clasts and matrix of some volcanic members of the volcanicarc assemblage along the centralaxis of the it differs from that in unit2, mainly in form. The analcite Quesnel belt (Figure 35). The thickest accumulations of grains in this unit are generally less than 2 millimebres in these volcanic rocks, including flow-dome complexes and size and roundto irregular in shape. Theyare most likelyto possibly intrusive breccias, outline centres oferuptive vol- occur in the more altered rocks, suggestiveof a secondary canism and subvolcanic intrusive emplacement along the origin. belt. Bailey (1978)has calculated an aggregate thicknessof The top of the unit consists of lenses of maroon sand- 2160 metres for this unit. stone, calcareous sandstone, conglomerate and massive, Unit 3 has been subdividedin the Morehead Lakearea pale grey limestone. Near Morehead Lake there is a thin, and the regionto the north of the QuesnelRiver by Bailey marine fining-upward clastic sequence of grey calcareous (1990, and earlier reports) into three subunits - 3a, 3b and sandstone,minor conglomerate and carbonaceous mud- 3c. These units, from lower to upper, are: a polylithologic stone and argillite. A few kilometres to the north of these breccia, a heterogeneous assemblageof tuff, sediment and rocks are interbedded sandstone, siltstone and mudstone breccia anda tuffaceous sediment and minor felsic breccia.cropping out along Morehead Creek.On the basisof strati- Fo the Horsefly area farther to the south, no stratigraphic graphic position and composition, the Morehead Lakesec- subdivisions were established in the generally massive, tion is considered tobe correlative withthat near Morehead unstratified andunsortedbrecciaandflankingconlgomerate Creek. Io this latter section Lower Jurassic macrofossils, deposits (F’anteleyev and Hancock, 1989a, and earlier dis- including the Smemurian index ammonite Badouriu cu- cussions). We now consider the plagioclase-lathpyroxene nadensis (Frebold),have been recognized, while at the phyric basalt flow and breccia in the Shiko Lake area, Morhead Lake locality an Early Jurassicage is apparent by previously referredto as unit 2g (Panteleyev and Hancock, the presence ofWeylu sp. 1988aJ to be correlative in age, if not composition, with the oldest parts of unit3. SUBAERIAL BASALT- UNIT 4 The rocks of unit 3 are generally pink to pale brown This unitis a distinctive darkpurple to maroon, vesicu- weathering and leucocratic in appearance. They contain lar and amygdaloidal, analcite andolivine-bearing pyroxene more abundant feldspars, notably alkali feldspar, than the basalt flow and breccia assemblage.Its limited distribution underlying pyroxene basalts of 2unit and therefore, appear in small segments of the central arc suggests that it was to be more felsic in composition. Both orthoclase (perthite deposited in a rift zone or elongate fault-bounded trough as clasts and in breccia fragments) and intermediate plagio-along the medial axisthe of volcanic belt (Figure 3-6). There clase (albitic composition according to Bailey, 1978) and is little lithologic variation in this unit. Flows and flow

30 Geob8ical Survey Branch Ministry of Employment aM Invesmenf

Photo 3-1.Typical outcrop appearance and fabric in basaltic units.A. Volcanic breccia of clast-supported, momomictic pyroxene phyric basalt typicalof unit 2. B. Lithic crystal ash to lapilli tuff containing some cognateeuhderal crystals and broken grains of analcite.

Bullelin 97 31 Brifish Columbia

Photo 3-2. Typical outcrop appearance and fabric‘felsic’ in shoshonitic basaltic rocks.A. Volcanic breccia withlithic ash matrix containing a wide variety of clasts including many from underlying volcanic units.B. Breccia with reddish, sandto mud-sized granular matrix and some clasts with reaction rims, suggesting laharic deposition. Clasts are dominantly pink, fine-grained and analcite-phyric, ‘felsic’ volcanics.

32 Geological Survey Branch Photo 3-3. Photomicrographs of unit 2 basalts. A. Olivine grains alteredto magentite, carbonate and iddingsite(?)partially t:nclou?d by diopsidic augite.B. Alkali olivine basalt. Euhedral olivine phenocrysts completely replacedby serpentine and magnetite, planepolarized light. C. Same as B., crossed nicols. D. Hornblende-bearing alkali basalt, crossed nicols.E and E Alkali basalt with calcite.Bar scale is 1 nun; scale is the sameon all photographs.

Bulletin 97 33 Photo 3-4. Photomicropphs of analcite basalt of unit Ze, sandstone and felsic brecciasof unit 3. A. Large analcite grain and diopsidic augite in groundmass of plagioclase microlites, analcite and devitrifiedglass. plane polarized light.B. ‘Primary’ analcite phenocrysts with sharp, unaltered contacts with rock groundmass. Note lack of evidence for replacement, plane polarized light. C. Same as B., crossed nicols. D. Matic sandstone composed of roundedgrains of clinopyroxene,feldspar and magentitein matrix of calcite and clay minerals, crossed Ncols.E. and E Polylithologic felsic breccia. Bar scale is 1 mm.

34 Geological Survey Branch Ministry of Employment and Inveslment

Photo 3-5. Photomicrographs offelsic rocks ofunit 3 and intrusive rocksof unit 7. A. Trachytic felsic flow, crossed nicols. Plagioclaseis slightly altered, potassium feldsparis almost completely replacedby calcite. B. Felsiccrystal tuff, crossed nicols. C.Calcarecos sandstone, crossed uicols.D. Hornblende and clinopyroxene-bearing monzonite, crossedniwls. E. Monzonite adjacentto Cariboo-Bell (Mt. Polley) copper deposit with orthoclase ‘flooding’of matrix and replacement plagioclase,of crossed nicols.E Nepheline syenitefrom the Bootjack stock, crossed nicols. Potassium feldspar has perthitic texture; nephelineis isotropic (black). Bar scaleis 1 nun; scale is the sameon all photographs.

Bulletin 97 35 British Columbia

breccias of fairly uniform composition dominate, with mi- CLASTIC ROCKS INFAULT BLOCKS - UNIT 6 nor units of laharic breccia A maximum exposed thickness A younger sequence of Middle Jurassic age, unit 6, of 620 metresis estimated by Bailey (1978). consists of polylithic conglomerate as well as bedded suc- The basalt contains varying amounts andsizes of phe- cessions of finer grained clastic rocks that are similar to nocrysts of pyroxene andplagioclase and smaller grains of rocks of unit5. This unit is characterizedand distinguished analcite and relict olivine. Grainsare euhedral to subhedral from the older clastic unit by the presence of a variety of in shape and average3 millimetres in diameter. Some dis- clasts derived from the underlying volcanic arc, continental play marked green pleochroism and simple twinning and and oceanic provenance as well as optical but not compositional zoning. Pyroxene diopsidic the presence of quartz is and rare granitic detritus. The map unit is poorly exposed augite incomposition and chemically indistinguishable along the fault-bounded western margin ofthe Quesnel arc, from pyroxenes ofunit 2 (Appendix A).Plagioclase forms near the boundary of the map area. Thin-bedded fine- euhedrallaths andanhedral blebs. Thegrainsareextensively grainedsediments in the Beaver Creek area contain replaced by sericite, clay minerals and zeolite. Plagioclase Aalenian fauna (Poulton and Tlpper, 1991). Coarse clastic compositions range fromAn48 to An42 and, thus, are about sedimentary units of unceaain includeage grey and maroon 10 molecular% more albitic than feldspars in the alkali polylithic conglomerate with granitic clasts and quartzose olvine basalts of unit 2a. No olivine remains, but idiomor- sandstone. A Bajocian age for these rocks is suggested, phic relict grains about 0.3 millimetre in diameter are re- based on observations outside the map area (H.W. Tipper, placedby alteration minerals, mainly magnetite and personal communications, 1987, 1992). Some of the iso- iddingsite. The olivine is commonly enclosed by pyroxene lated conglomerate outcrops in the Beaver Creek valley grains. It forms about 10% of the rock butconstitute may up contain Cache Creekchert, limestone, greenstone and argil- to about 50%. The analcite occurs as euhedral phenocrysts lite and are, therefore, derived largely from westernsource averaging 0.5 millimetre in size and also as small grains in areas. These rocks also contain rare clasts of granitic and the groundmass. It is generally pink incolour but lacks the quartz-bearing dike rocks and quartz-bearing sandstone. twinning seen in the maroon to red analcite-bearing rocks Other conglomerates and associated clastic rocks contain of unit2e. Other minerals commonly presentare magnetite, abundant basalticdetritus and are derived from the Quesnel calcite and zeolite; the latter two mineralsare locally abun- volcanic arc. The age of some of these conglomerates is dant in vugs and veinlets. Zeolite minerals identified by uncertain: they might asbe young as Cretaceous andequiva- x-ray diffraction are thompsonite, scolecite and analcime. lent to rocks of unit 9. Thegroundmass is hematitic andextensively altered. Where grains can be recognized, they are analcite, magnetite and, in some cases,felted aggregates of plagioclase microlites. CONTINENTAL CLASTICAND VOLCANIC DEPOSITS OVERLAP UNITS FLUVIAL DEPOSITS- UNIT 9 Sedimentary units in the Quesnel beltare found in two Conglomeratewith abundant rounded cobbles and northwesterly trending belts (Figure 3-7). The clastic detri- boulders of chert, quartzite, other metamoxphic and sedi- tus, at least the coarsest part, is derived largely from the mentary rocks, various volcanic lithologies, some ul- volcanic arc. The two sequences are distinguished on the tramafic detritus, rare graniticclasts and whiteto grey (vein) basis of age and, to a lesser extent, lithologic type and quartz clasts occurs as narrow sinuous belts of overlapping provenance ofclasts in congomerate. clastic deposits on the northern flank of the volcanic belt in the Quesnel Lake and Quesnel River areas.The conglomer- CLASTIC OVERLAP DEPOSITSUNIT 5 ate is readily identified by its rounded polylithic clasts and - calcareous sandy matrix. Commonlythe carbonate forms an The older, Early Jurassic sequence, unit 5, was depos- orange-weathering, fine-grained interstitial matrix such as ited as volcanic-source epiclastic deposits. The mks over- that seen in the rocks of Cariboo Island in Quesnel Jake. lap the volcanic arc rocks and flank them in fault-bounded Elsewhere, for example, the Rose Gulcharea, orange- troughs or a postvolcanic marginal basin. Thisunit forms a weathering carbonate occurs in veinlets of spany dolomitic sequence of dark to medium grey, thin-bedded, fine-grained calcite. This carbonate cementation and vein filling appears calcareous sandstone andsiltstone along the eastem side of to be due to the action of late thermal fluids or groundwater. the volcanic arc. The rocks are similar in composition and McMullin (1990) hasdescribed the conglomerate near appearance to rocks of unit 1 as well as the flaggy beds of Likely as well as the lithologically similar rocks near Cot- pyritic siltstone and sandstone ofunit 2f. The sedimentary tonwood Riverat the northeast comer of the map area. The rocks of this unit are best exposed along the banks of the latter may beequivalent to the Likelysite but are probably Quesnel River to the northwest of the village of Likely. Jurassic in age and possibly equivalent to rocks of unit 6. There, in the south bank of the river, the bedsare overlain Lithologically similar rocks also occurin small fault blocks by basalts of unit 2 along a shallow, west-dipping thrust in the Beaver Creek valley. Therethe conglomerate uncon- fault. formably overlies volcanic rocks of unit 2 at Antoine Creek,

36 Geological Survey Branch Ministry of Employment ano'lnvesrment "

above a thin layer of hematitic red sand and soil derived brownbiotite-phyric sanidinebearing latitic flows(unit from thevolcanic rocks. At Rose Gulch, near Quesnel Forks,loa). The rocks consists of about 15% plagioclasecrystals there is a rhythmic sequenceof fming-upward conglomer- and pale yellow and honey-coloured dolomitegrains 'up to ate, sandstone and thin-bedded siltstone, some of which 2 millimetres in size. Raregrains and crystal ag::regates of contains dolomitic veinlets. The mudstone commonly con- glassy sanidine upto 4 millimetres in size are also present. tains leaf impressions of monocotyledons (Bailey, 1978) Biotite flakes up to 2 millimetres across form about3 to 5% and similar rocks on the south side of the Qnesnel River of the rock. This rock type is present as clasts and is the contain nondiagnostic carbonaceous plant trash. source of the abundantbiotite grains in the pebbb: conglom- Provenance of many of theclasts in the conglomerate erate at the base of unit 10 where it is exposed along the is the eastern metamorphic belt of the Barkerville Terrane Horsefly River at the historic Hobson placer mining s:ite. A and, to a lesser extent, oceanic rocks of the Slide Mountain Middle Eocene radiometricdate has beenobtain XI from the Terrane (McMullin, 1990). The age of the map unit is biotite contained in the flow rocks. A biotite-hming lam- possibly Albian, or younger, (H.W. Tipper, personal com- prophyre dike of similarage (unit IOc) that cuts nxks ctunit munication, 1992). if the rocks are equivalent to the con- 1 in the Beaver Creek valley is probably a feeder for the glomerate in Beaver Creek valley at Antoine Creek. This flows. Tertiary dikes are rarely seen inthe map area. age is based on unreported data from palynology samples To the north of Quesnel Forks, near the confluence of collected by R.B. Campbell and examinedD.C. by McGre the Qnesnel and Cariboo Rivers, biotite-bearing vol.canic gor (H.W. lipper, written communication, 1993, Report rocks are exposed which, although superficially resembling F1-12-1967-DCM). These coarse clastic deposits are sug- the breccias and tuffsof unit 3, are probably corrdative with gested by Tipper to represent ancient fluviatile systems of the similar biotite-bearingrocks near Horsefly. possible Cretaceousage that had theirorigins in an Omineca The second volcanic lithology consists of pale greyto highland following uplift in the Toarcian. Alternatively,all brown, commonlyiron stained, and mauveto purple plagio- or part of the channel-fill conglomerateunit may be Tertiary. ctase-phyric crystal ash-flow tuffs (unit lob). Small lithic Certainly Quesnelliaarc and coverrocks have been repeat- clasts are commonly present but aregenerally kss than 5% edly eroded. in abundance. The rocks are usually compacted with blocky fracturing outcrops. Locally, there is faint, indistinct layer- TERTIARY SUCCESSIONS- UNIT 10 ing defined by a weakly developed foliationis im:partedtha!. by plagioclase crystal alignment. Some outcrops, notably Tertiary felsic and sedimentmy rocks in the map area those with foliated rocks, display slahby to platy fracluring. (Figure 3.8) are Middle Eocene in age according to both Plagioclase crystals less than 1 millimetre upto 5 millime- fossil and radiometric data. The rocks can be observed in places, to overlie rusty basaltic Nicolarocks along a tres across make up about 50% of the rock. The plagioclase lateritic-looking soil horizon that marks the unconformity. crystalsare euhedral and blockyto tabular in shape and have well developed albite and Carlsbadalbite twinning. The This deep weathering in the basalts suggests there was composition is oligoclase Ann-29. Mafic minerals, origi- considerable tropical weathering at the start, or during, the Eocene. The Eocene rocks have been subdividedinto sedi- nally probably amphibole,are completely replaced by calcite, epidote, dusty hematite and other opaque minerals. mentary andvolcanic subunits: Magnetite grains are extensively to complete:.y altered to maghemite. Grains of rounded, resorbed quartz occur spo- LACUSTRINE SEDIMENTS -UNIT 10 radically throughoutthe rock. The quartz and small, #cloudy Pale grey to fan and yellow, thin-bedded to varved grains of interstitial orthoclase form less than 15% of this lacustrine deposits of clay, silt and fine-grained sandstone rock. The ashtuffs overlie Middle Eocene sedirnenkuy beds withsome tuffaceuons component are foundalong the at Hazeltine Creek. Elsewhere, for example the Megabuck Horsefly River, nearthe mouth of Hazeltine Creekat Ques- property to the south of Horsefly village, feldspathic ash ne1 Lake and along Victoria Creek, northof Quesnel River. flows occur together and possibly intedinger witin tine- The well-bedded successioncontains abundant plantdebris grained tuffs and tuffaceous sedimentmy rocks. The tuf- and floral imprints. Abundant palynomorphs confirm aMid-faceous sediments are variably purple to green and grey in dle Eocene age of deposition. Rarely,fossil fish and insects colour. Some beds andsuccessions contain hgeclots and can be found. Wilson (1977a,b) regardsthe Horsefly River spherules of fine-grained epidote. These subaqueous tuffs locality near Horsefly village, locally referred to as 'The probably grade laterally andinterfinger with the lacustrine Steps', as one of the type localities in Canada for Eocene sediments of unit 10. fossil fish. NEOGENE PLATEAU BASALTSAND VOLCANIC FLOWS, ASH FLOWS AND CRYSTAL MIOCENE FLUVIAL CHANNEL DEPOSITS- ASH TUFFS - UNIT 10a UNITSI1 AND lla 'ho main lithologic types are recognized. A single Dark grey to black and maroon alkali olivine hasalt exposureonaknolltothewestoftheHorseflyRiverconsists subaerial flows and tephra cover muchof the southwest part of platy, fine-grained homogeneousto porphyritic, grey to of the maparea (Figure 3-8). The rocks are lypical of the

Bulletin 97 37

~ British Columbia

UNIT ...... QUATERNARY Qal Glacial fluvioglacial deposits, alluvium MIOCENE 11 11 14.6 Ma - Darkgrey to blackalkaliolivine plateau basalt EOCENE Ila white dominantly with polymictic Gravel: honate-cemented quartz cobbles; locally carbonate- 10b cemented conglomerate cemented 10b 52 Ma - Pale grey to yellow and tan thinly bedded lacustrine siltstone and sandstone; abundant 10 ___\j I wood trash and floral imprints; rare fossil fish. .. "- __ Locally polymictic conglomerate; contains L"""" """ some tuff beds ". "" " - 1Ob Pale grey to brown, commonly iron-stained or pale mauve and purple feldspar-phyric - clasts,of 10a crystal-ash flow tuffs; locally compacted and layered 1 Oa 52 Ma - Grey platy biotite-phyric latitic flows JURASSIC (Sinemurian - Pliensbachian) 3 186 Ma - Grey to olive-drab hornblende porphyryflows and/or sills

v"v"vvv"vvv" TRIASSIC (Norian) """VV"VVVV v vv "V" 2 Pyroxene-phyric flows and breccia

sw NE

sure 3-9. Diagrammatic saatigraphic section and cross-section showing Tertiary and Quaternary map units and the Miocene chann uiferous) gravel deposits.

38 Geological Survey Branch MAP UNITS

*""'"""

Narlan camIan Anlslan .LadinIan PENNSYLVANIAN-PERMIAN DEVONIAN. PERMIAN PROTEROZOIC~MlSSlSSlPPlAN

wiw

Figure 3-10. Generalized geological map showing units7 and 8 ~ intrusive rocks. widespread plateau basalts, termed Chidcotin Group vol- smaller stocks and plugs, domes, dikes, sills and intrusive canics by Mathews (1989). that cover much ofsouth-central breccias, all within a complicated three-cycle sequence of British Columbia. Commonly flows display well formed intrusive-extrusive magmatism. Heplaces olivine and alkali columnar joints. They give rise to flat-topped outliersand gabbros, syenodiorite, monzonite and dikesof syenite and rimrock scarps that are the eroded remnantsof previously trachytein the oldest magmatic cycle, and assigns more exteusive plateau basalt flows. At least two ages of nepheline-bearing syencdiorite, monzonite andtheirrelated flows are present in the map area according to Mathews dikes as well as analcitebearing olivine teschenite, tes- (1989): a 14 to 16 Ma series and a 7 to 9 Ma flow series.A chenite, tephrite, phonolite and other dikes to the two younger series of flows, 1 to 3 million years in age, has not younger cycles. His proposed intrusive scheme has not been been recognizedin the map area.In places the flows contain substantiated by this investigation but some of his rock ultramfic,orthopyroxene-bearing xenoliths. Locally, the descriptions and petrological dataare incorporated here. base of the basalt unit has a bentonitic palagonite ash and tephra layer with abundantbasaltic scoria. ALKALJC GABBRO-DIORITE-SYENITE- A conglomerate unit underlies the basalt flows in a UNIT 7 number of gravel-filled river channels. It is shown as unit Stocks ranging from diorite to syenite in composition 1la (Figure 3-9). The gravels consist of a distinctive white intrude sedimentary rocks of units 1 and la and the older quartz cobble congomerate that placer miners in the area volcanics of unit 2. They appearto be coeval andcogenetic refer to as the Miocene (placer gold) channel. The white with the alkalic volcanics of unit3. Anumber of the dioritic quartz clasts appear to be derived from coarsely crystalline bodies are composite stocksor are zoned due to differentia- vein quartz. At its base, at least in the Horsefly River valley tion into monzonite and syenite phases. The intrusions are in thehistoric Hobsonplacer mine, the gravel is cemented assigned to unit 7 on the basis of their alkalic compositions with calcite.It forms a resistant conglomerate in which adits and Early Jurassic ages (see following chapter).The K-Ar and other underground openings were drvien that permitted radiometric dates from the stocks, including some samples extensive underground miningof the auriferous gravels. of hydrothermal minerals, range from 208 to 182 Ma. A mean age of 195 Ma (EarlyJurassic) is obtained fromten of QUATERNARY DEPOSITS- UNIT Qal the most merit K-Ar radiomehic determinations (see Table A durable blanket of one or more tills, local ablation 4-1). More recent U-Pb dating indicates intrusive ages of moraine and widespreadfluvioglacial deposits with an ex- approximately 202 Ma (Ghosh, 1993;1994). tensive thin cover of colluvium and other overburden is Unit 7 has not been subdivided in this studybut can be present throughout much of the map area. Drumlins and readily split into subunits that are differentiated on the basis crag-and-tail features that indicate northwesterly ice-flow of composition and texture. For example, Bailey (1990) directions are common on the plateau. Fluvioglacial depos- describesthreesubunitshedesignatedasunits7a,b,c,These its and some thickaccumulations of glacial silt are foundin are: 7a - pyroxene-bearing diorite, monzonite and syenite themajorvalleysoccupedbyBeaverCreekandtheHorsefly with lesser gabbro, clinopyroxenite and peridotite; 7b - and Quesnel rivers. syenite with characteristic large othoclase phenocrysts and megacrystic texture; and7c - nepheline-bearing syenite, in INTRUSIVE SUITES partorbicular. All therocks contain normativenephelineand lack modal quartz. Two groupings of intrusive rocks are evident, basedon The mcst abundant intrusive rock type is fine to me- the age and compositions of the major intrusions (Figure dium-grained, equigranular to weakly porphyritic syeno- 3-10). An oldeq latestTriassic to Early Jurassic alkalic suitediorite and less commonly diorite. Thesyencdiorite is grey (unit 7) is coeval with some of the younger arc volcanism. in colour and composed mainlyof fine to medium-graiued These mks represent the most commontype of innusions plagioclase, orthoclase and clinopyroxene. Crystalsize gen- found in the project area. A single pluton of quartz-bearing erally ranges from0.5 to 1.5 millimems. Therock contains, granodiorite in the southern part ofthe map area, part theof on average, 50% plagioclase of andesine composition Takomkane batholith,is evidently also Early Jurassic agein (An34-52), 15% diopsidic augite and up to 25% anhedral, (Campbell,1978). It represents a separate, calcalkalic poikilitic orthoclase. as the main groundmass component magma type that is distinct from the main group of silica- Hornblende occurs in variable amounts together with acces- undersaturated alkalic dioritic magmas. The stock is in- sory magnetite (up to 5%). apatite and sphene. Biotite is cluded in the Early Jurassic unit 7 as a silica-saturated present, generallyas a replacement of clinopyroxene: some subdivision (unit 7A) on the basis of its similar age. The of the pyroxene is rimmed by aegerine or aegerine augite younger suite of intrusions (unit 8)are calkalkaline, quartz- (Bailey, 1978). Other alterationmineralsare sericite, calcite bearing stocks of probableCretaceous age. and chlorite. Monzonite hasthe same mineralogy but has an Morton (1976) described the intrusive rocks in the orthoclase. content of about 35% and, in places, abundant Horsefly area in detail and classified many rock types ac- biotite. The rock is usually pale grey to pink in colour. cording to their compositions. He subdivided the intrusive Syenite contains abundant microperthite andorthoclase of bodies accordingto their size into major plutons and related which much,if not most,appears to be a secondaq replace-

40 Geological Survey Branch ment of groundmass and plagioclase phenocrysts. Plagio- ated hydrothermal alteration and coppermineraliraton. The clase compositions range fromoligoclase to albite (An22- plutons in the sedimentary rocks of the underlying basin-fill 6). BothSchink (1974) and Morton (1976) report the assemblage, and presumablyat greater depths, tmd to have presence of small amounts of flnorite in syenite. Gabbrois thin ‘dry-looking’ thermal aureoles (hornfels) with little a minor component of the Polley and Lemon Lakestocks evidence of deuteric alteration within the stosk, or hy- (Hodgson et al., 1976; Morton, 1976) and both gabbro and drothermal products in the countryrocks. serpentinized peridotite form parts of the Cantin Creek The largest pluton,comprised of anumber of intrusive intrusions &u, 1989; RE. Fox, personal communication, phases (Hodgson et al. 1976, Bailey, 1978), is the Mount 1987). Polley stock. It is a high-level compositestock made up of A number of the stocks, even the smaller ones, are a laccolith-like series of sills, dikes and intrusica breccias zoned. Some display symmetrical zoning with gradational (Fraser, 1994).It is possibly the highest level pluton exposed changes from cores of monzoNte or syenite to a rim of in the Quesnel belt and coincides with the largest accumu- diorite, for example, the QR stock. Thedioritic rims contain lations of felsic volcanic deposits of unit 3. Note that the more abundant mafic minerals and magnetite than the cen- term ‘high-level’is a relative term. Onthe basis of intrusive tres of intrusions and consequently have a strong magnetic morphology, Sutherland Brown (1976) estimated the em- signature. Other intrusions, probably the higher level sub- placement of the Mount Polley stock at a depth of about a volcanic stocks, are commonly composite. They have intru- kilometre. Sillitce (1989), inhis discussionsof young island sive (and possibly metasomatic) internal contacts, for arcs in the southwest Pacific and their intrusion-related example the Bullion Pit stock. In the composite stocks,the deposits, considers 0.5 to 1-kilometre emplacenent depths various constituent map units may display irregular shapes tobe‘shallow’.Inanycase,theMountPolleystor:khasbeen and geometries. emplaced in an epizonal environment and has ;ample evi- Coarsergrained to megacrystic variants of mainly mon-dence of high-level, subvolcanicintrusive phenomena such zonite and syenite are present, usuallyas minor components as extensive brecciation and related hydrothermal activity. ofanumberofthestocks.AtboththePo1leyandShikoLake Other stocks in the Quesnel belt,especially tho% intruding stocks there are small zones or pods of pegmatitic syenite. lower stratigraphic units and those with regular,:ylinClrical Janprophyric dikes and irregular zones of granophyric shapes andsteep, sharp contacts, appearto be deeper intru- syenite that contain coarse flakes of biotite and long, thin sions. For example, Schink (1974) suggested a 6.5-kilome- hornblende needles are also found within the stocks. Peg- tre, or deeper, depth of emplacement for the Shiko :Lake matitic, orbicularand granophyrictexturesare foundlocally stock on the basis of geological mappingevidewe. in stocks of nepheline syenite suchas the Bootjack Lake and A hornblende-bearing syenodiorite intrusive breccia Mouse Mountain stocks. The coarsest grained parts ofthe exposed on the peak of Viewland Mountain was for sampled intrusive bodies are the core regions; grain size typically radiometric dating.It produced one of the older IGAr dates diminishesoutwards into very fine grained, more mafic-rich in the map area - 203 million years. Morton (1!)76, pages border zones. Thecomer grained rocks contain nepheline, 37-40) describes the breccia as an intrusive mcozodiorite orthoclase, aegeriue augite and less abundant biotite, horn- brecciacomposed mainly of roundedfine-grained blende, albite and magnetite. Pseudoleucite andanalcite are syendiorite clasts and minor clasts of other lithclogies. He present in places, commonlyas cores of the orbicular struc- reports that this rock type occupies500 a by 400- metre area tures surrounded by nepheline, orthoclase andmafic near the peak of the mountain.The dated samplein this study minerals. is also from the Vlewland Mountain peakarea, presumably from the same outcrop examined by Morton, butis from a The plutons are emplaced alongthe central axis of the clast of monolithologic brecciaof hornblende porphyry. The volcanic arc or, less commonly, are to the east of it in the breccia formsa body, a 100 but less than 200 metres across, sedimentary rocks of underlying units 1 andla. There is a that caps the peak of the mountain.the On slopes below the frequency of intrusive emplacement at approximately 11- peak the brecciais underlain hy pyroxene basalts unit of la. kilometre intervals along the volcanic belt. The intrusions The porphyry contains about 40% hornblende laths 1 to 2 appear to coincide with centres of eruptive volcanism and millimetres in length or as rare glomeroporphylitic g:rains arc construction. Intrusive lithologies thatoutline the intru- up to 4 millimetres across. Smaller phenocrysls and mi- sive-extrusive centres are present as clasts in ventand crolites in the plagioclase crystal groundmass account for proximal breccias as well as in the surroundinglaharic and about 50% of the rock volume.Plagioclase composition is slump deposits. The plutons intrudedat higher stratigraphic labradorite (An58-70). The rockis weakly alterej and con- levels, as a generalization, appear to be more irregular in tains minor chlorite,calcite and epidote. shape, have late dikes and are associated with proximal volcanics that are more differentiated felsic magmas with QUARTZ DIORITE/GRANODIORITE - hydrous mafic minerals hornblende and biotite. Someof the UNIT 7A intrusions have associated pegmatites and intrusionor hydrothermal breccias. A number of the subvolcanic stocks OtherLateTriassic to Early Jurassic plutonsincludethe display some evidenceof deuteric or other types of associ- granodiorite, quartz monzonite andquartz diorite intrusions of the Thkomkane batholith that cmp out to the south of diorite exposed in a single road cut 2.5 kilometres to the Horsefly village (Campbell, 1978) and in the adjoining northwest of Shiko Lake. BonaparteLakemapareatothesouth(CampbellandTipper, 1971). The rocks a few kilometressouth of Horseflyare grey QUARTZ MONZONITEALASKITE - UNIT 8 medium-grained, equigranularto weakly porphyriticquartz Quartz-bearing rocks with calcalkaline compositions diorite. Plagioclase grains up to 5 millimetresin size consti- form stocks of medium to coarse-grained granodiorite, tute about 55% of the rock. The finegranular groundmass quartz monzonite and minoralaskite. These rocks occurin is made up of approximately15% quartz, 10% hornblende the large Nyland Lake stock,the smaller Gavin Lake stock and roughlythe same amount of orthoclase. Epidote, chlo- and dike complex anda number of small, unnamed quartz- rite and calcite extensively replace the hornblende. At the bearing dikes 7 kilometres to the southeast of Gavin Lake. Megabuck property these rocks are hydrothermally altered The rocks are most commonly pale grey, medium-grained andcutbyquartzvein1ets.Thealteredrockscontainepidote. quartz monzonite whichin places ranges from fine-grained sulphide minerals, magnetite, and locally clay minerals, quartz monzonite to porphyritic alaskite. They are consid- sericite and black tourmaline. ered to be of Cretaceous age (Bailey, 1978) and possibly A second intrusion, possibly belongingto this subunit, equivalent to the NaverPlutonic Suite of the northern is a crumbly andrusty weathering, medium-grained quartz Quesnel Trough.

42 Geological Survey Branch Ministry of Employment ond Ien

CHAPTER 4 AGE OF MAP wrs- PALEONTOLOGY AN:D GEOCHRONOLCIGY

The ages and correlations of lithologies were estab- separates of hornblende and biotite was performed at the lished by studies of macrofossils and microfossils from University of British Columbia GeochronologyL~boratory. sedimentary rocks and radiometricdates from igneous rocks Thirteen new K-Ar age determinations from r0c:ks of the (Figure 4-1). Thii-six samples from beds of limestone and various intrusive and volcanicunits are reported in Tabk4-1 silty limestone to calcareous siltstone were collected for and shown on Figure 4-2. conodont extraction.The samples were dissolvedin acetic acid; the sieved, dried residue was examined and conodonts MICROFOSSILS were identified by M.J. Orchard, Geological Survey of Canada. Three samples takenforpalynology were examined and reportedon by G.E. Rouse ofthe University of British CONODONTS Columbia. Twenty sites in which macrofossils were discov- Six samples, all from unit 1, yielded conodonts. Key ered were sampled and the collections submitted to H.W. taxa identified are: Chiosella fimorensis of early Ani.sian Tipper for study or referral to T.P. Poulton and E.T. Tozer, age, Neogondolella constricta of late Anisian-t:arly lid- all with the Geological Surveyof Canada.’bo of the fossil inian age, Metupolyg~fhusex g,: nodosus of lale Carnian sites located to the south of Quesnel Lake (C-117285 and age, and Epigondolella sp. ofNorian age (Orchard,in C-117286) were resampled bylipper and later reported on Appendices B, C). In addition, a number of the samples to the authors. All site locations and other dataare given in contained ramiformelements and indeterminate ifxhyoliths, Appendices B,C, D and E. Radiometric datingon mineral shell fragments, worm tubes and a single, nondiapostic

I ‘\i”-mMamMa mnodonis Anisian

Crooked amphibolite

Figure 4-1. Central Quesnelbelt time-stratigraphic units with diagnostic fossils and radiometric ages,

BuIlelin 97 43 Briiish Colwnbin

TABLE 4-1 RADIOMETRIC AGE DETERMINATIONS; POTASSIUM-ARGON ANALYTICAL DATA,THIS STUDY AND OTHERS

Sample Localion Material Ar@(lO.") Ar@ Apparent N2lBlt.S Wm Lithology Analysed %K (molerlg) Total Are Age (Ma)

I. 88AP4l8-12 629Mx) Horsefly Mountain sulek 0.918 hornblende 94.3 3.507 2086 5802300 diorite

2.88AP?.SI1-76 624800 Wcwland Mountain breccia hornblende 1.01 3.792 90.7 204+7 5810200 hornblende porphyry clast

3. DB-87-2 591300 Bootjack stock hornblende "ArFAr plateau age 203.1 Q.0 581%50 nepheline syenite (Bailey and Archibald, ISW)

4.85AP21i2-120 581450 QR stock biotite95.2 14.565 3.95 20k7 5835300 diorite (chloritized)

5.85AP7t2-63603750 Shiko stock hornblende 0.82891.8 2.067 196t7 5812800 hornblende porphyry dike

6.85AP811-64M)3550 Shih Emck biotite 16.408 4.67 86.7 192t10 5813000 mommite cat me

7.85APsl1-64 603550 Shiko Emck biotite86.7 16.408 4.94 1826 5813000 momnite core wne

8.85APW-71 591900 Bullion pit nak biotite 19.037 5.4 193*7 87.7 5831900 diaite

9. 617600 LemonLakeEmck w analytical data, 187+Ma age reported by Pilcher and 192 586D750 mndiorite McDougall(1976); age recalculated with new constanll

10. 592050 Mount Polley stock hydrothennal biotile(Harigson et d.. 1976) repoaed as I88e7 5822850 Cariboo-BeU deposit 184t7 Ma; recalculated using constanll from Steiger and lager (1977)

11. DB88-03 546800 cotmnwood ~iverstock hornblende 91.21.98 6.776 187i7 5881500 pyroxene hornblende gabbro

12.87AP6/3-16 605670 Unit 3 hornblende 0.642 to.240 2.181 97.2 18~7 5799080 hornblende porphyry flow or dike

13.86AFZW6-64 611250 Kwnsurk biaite 5.00 16.932 89.8 18.56 5806MX) biotite monzonite

14.88AF'11/5-36 581500 Unit ICC 6.08 biMite 5.702 72.6 53.3A.7 5811000 biotite lampmphyre dike

15.87AP3/14 603440 Unit 1OA biotite 7.250 to.020 6.662 93.2 52.2i1.8 5799080 biotite lrachyandesite flow

16.87API8/8-44 601710 unit I1 whole mk 0.722 M.008 0.1838 33.4 14.6M.5 5797170 plaleau basalt

17.87MAB35632 61W Frasergold quam vein serieite 872iO.10 91.3 23.759 15M

44 Geological Survey Branch Figure 4-2. Generalized geological map with radiometric dating sample sites;this project, age in Ma. formaniferid (Appendices B, C). Three samples from unit Canada. Much of thesite data and identifications are listed 2a were banen. in Appendix E and have been utilizedby Campbell (1978) The presence of Middle Triassic (Anisian) fauna in in preparation of his Quesnel Lake 1:125 000 geological rocks overlying younger rocks near Spanish Lake is inter- map. New collections andidentifications from this project, peted by Smik (1986,1988a) to be due to thrusting within and some older data, are contained in Appendix E and the metasedimentarysuccession of unit 1. Bloodgood's summarized on Figure 4-1; these data, andother informa- work in the area supports Smik's interpretation for the tion, are have been reported byH.W. Tipper (written com- Spanish Lake area but theexistence of similar relationships munications,Report J1-1993-HWT, 1993,and older throughout the region is not demonstrable. reports). The colour and preservationstate of the conodonts, as Unit 1, in additionto conodonts, contains beds near the indicated by the colour alteration index (CAI)of Epstein et top of the succession withHalobia. This fauna, and possibly al. (1977),showsaconsistent relationship withstratigraphic Monotis, is also found in rocks of unit 2, mainly in small position and increasing metamorphic grade within the me- lenses of reefoid limestone and limestone-cemented basalt tasedimentary succession(see Chapter 6). The least meta- breccias. Thetop of the basalt successionis marked locally morphosed, subgreenschist,zeolite to prehnite-pumpellyite by fetid beds with a trigonid-bearing, rich shelly faunal grade volcanic rocks of the central Quesnel belt havea CAI accumulation. The Sinemurianrocks of unit 3 contain the of 2.5 to 3.5 in the contained Norian sediments. The under- diagnostic ammonites Badouxia canadense and Bodouxia lying sedimentaryrocks have CAI from3.5 to 4.5 at the top columbiae of the Early Jurassic, lower Sinemurian, Ca- of the succession (unit 1) and 4.5 to 5.5 in the deeper and nadensis Zone, as well as the bibalve,Weyla. Badouxia bas structurally more disruptedolder parts of the Quesnel belt. been referred toin some earlier reports as Psiloceras (Calo-. ceras) canadense. The presence of both Pliensbachian and PALYNOMORPHS Aalenian clastic assemblages is documented by a number of Three samples from the Tertiary, lacustrine, varved ammonitesincluding Arieticeras, Amaltheus and Eryci- sedimentary beds of unit 10 were submittedfor palynologi- toides. Tertiary rocks and conglomerate of9 ofunit possible cal analysis. They include two from the area of waterfalls Cretaceous age commonly contain abundant wood debris on the Horsefly River known as The Steps, 7 kilometres and plant fragments, but none collected are diagnostic. downstream from Horsefly village,and one from Hazeltine Palynormorphs, fossil fish and insects are charac- Creek near its mouth at Quesnel Lake. The samples were terisitic of theMiddle Eocene varves of unit 10. The Horse- examined by G.E. Rouse at The University of British Co- fly River samplesite at The Steps is also a type locality for lumbia. He confirms the presence of a mid-Eocene assem- Eocene fossil fish, including Amyzon aggregatum, otherand blage of angiosperm pollen, conifer pollen, fungal spores, fossil materials describedby Wilson (1977a,b; 1984). The algal cysts and fern glochidia. Diagnostic palynomorphs Amyzon was a fresh-water lake fish related to the living are: Pistillipollenites mcgregorii,Sabal granopollenites. buffalofishes and suckers. Fossil insects collected by Ailanthipitesberryi, Gra~tisporitescotai~,Rhizophagites R.B. Campbell (GSC Catalogue No. 20 and 22) and de- cerasifonnis, Rhoipites retipillatus, Araliaceoipollenites scribed by H.M.A. Rice (Report No. Misc. l 60/61 HMAR, granulatus, Pluricellaesporites, Multicellaesporites -6, H.W. Tipper, written communication, 1993)contain a vari- Tetracellaesporites sp., Diponsporites sp., and glochidiaof ety of well-preserved Diptera, Hymenoptera and Hemiptera thewaterfernAzollo.Alistofallpa1ynomorphsdocumented similar to those from other Tertiary basins in theprovince. is given in AppendixD. The most common species are Plecia pictipennis (Han- The overall assemblage representsa mixed mesophytic lirsch) (March fly)and Plecia similkameena Scudder, forest, similar to present forests of southeast North America among others, all indicative of a tropical or semitropical and central China. Temperatureswere warm, borderingon climate. subtropical, and precipitationwas much greater than present amounts. The presence of Lejeunia algal cysts confirms RADIOMETRIC DATES aquatic, probablylacustrine deposition. The Horsefly River - Hazeltine Creek assemblageof unit 10 is correlativewith The thirteen K-Ar ages,a single Ar-Ar date and other other mid-Eocene assemblages between48 and 52 Ma in data generatedby this study are listed in Table4-1. Sample age, equivalentto rocks of the Kamlwps Group. The Horse- locations and the matigraphic relationships of dated li- fly River sample site at TheSteps also contains abundant thologic unitsare shown onFigures 4-2 and 4-3. Radiomet- fossil plants andlesser fish and insects. ric agesof the diorite to monzonite stocks range from 208 to 182 Ma (NorianEZettangian to Toarcian) witha mean of MACROFOSSILS 193 Ma(Pliensbachian), on the time scale of Harlandet ai. (1990). A mean age of 196Ma (late Sinemurian) is obtained Extensive collections of fauna collected at various from the hornblendedates, and 190 Ma (late Pliensbachian) times in the Quesnel Lake area, notably from outcrops and from the biotite analyses.Recent U-Pb dating using zircons placer mine workingson Morehead Creek and other nearby (Ghosh, 1993; Mortensen, 1994)provide4datesaround202 areas, are in the repository of the Geological Survey of Ma from the Mount Polley and Bootjack stocks that are

46 Ceobgicai Survey Branch Ministry of Employment und le%r

BAJOClAN I d m (I) AALENtAN 1 UNIT Y t- ,- 180 I TOARCAN

PLIENSBACHW

i I t 1 NORIAN 1

0 K-Ar hornblende 2201"-l UNIT 1 CARNlAN a Ar-Ar hornblende 0 K-Ar biotite -1 K-Ar biotite? X 240 I U-Pb

Figure 4-3. K-AIradiometric ages and stratigraphic relationshipsof alkalic stocks and other datedrocks of the central Quesnel belt. Data in brackets from other shldies; numbers referto data in Table4-1. 'lime scale is thatof Harland er aL (1990). considered be the age of intrusion. These close the to are to Mid-Tertiary magmatic activity is confirmel by the52 203 Ma Ar-Ardate Of the Bootjackstock repowby Ma date of biotite from latite flows of unit loa. These rocks and Archibald (1990). An interpRtationofthese data is that have provided the distincitive biotite-bearing clas~,and the ageof intrusive emplacement was around200 Ma and the younger dates represent a loss of argon dueto thermal biotite flakes in basal beds of the Eocene lacwtrine sedi- effects,probably during late deuteric activity or hy&,ther- mentaryunit.AdikeofS3Mabiotite-bearing'lamprophyre' me only volcanic arc rock dated is a that intrudes unit I attests to the more widespre2.dpresence zeolitized hornblende porphyry of uncertain flow, dike or of Tertiary rocks in the map area. They are probably a subvolcanicplug origin; its I86 Ma age is compatible with manifestation of the widespread, regional extmsion that its correlation with unit 3. took place in central BritishColumbia during Fncene time.

Bulletin 97 47 Miocene and younger volcanic rocks referred to by tains a Norian Trigoniid fauna in strata which underlie Mathews (1988) as the Chilcotin Group occur in three Badouxia beds of Sinemurian age. Elsewherein the central groupings according to their age: 14 to 16,6 to9 and 1 to 3 Quesnel belt, however, the uppermost Norian and Het- Ma. The older rocks form extensive flat-lying flows that tangian appears to be marked bya hiatus in volcanism and cover extensive areas of the interior plateau; the two sedimentation which, in places, may be represented by a younger groups of flows fill valleys. The oldest group is slight angular unconformity. A similar relationship exists represented in the map area by 14.6 Ma basalt flows. The between Triassic mafic volcanicrocks and overlying, more dated rocks overlie thin units of Tertiary sediments (unit 10) felsic, volcanic rocks of Early Jurassic age elsewhere in and a Miocene channel-filling gravel (unit lla) at Gravel Quesnellia (Nelson er al. 1993; Nelson and Bellefontaine, Creek. Similar basalt flows capping auriferous Miocene 1996) and in Stikinia (Monger, et al., 1978); Logan and gravels occur a short distance away in China Cabin and Koyanagi, 1994). Moffat creeks.The dated sample is from the same outcrop Earliest Jurassic volcanism (unit 3) probably began as specimens with a 12.1 Ma age reported by Mathews during the Sinemurian and, unlikeLate Triassic volcanism, (1988). An identical 14.6 Maage was obtained by him from occurred from discrete volcanic centres. Productsof Early similar flows at Miocene, 16.5 kilometres to thewest. The Jurassic volcanismare trachyandesitic tolatitic in composi- presence of younger flows near OpheimLake and MacIn- tion and were erupted mainlyas breccias. Monolithic brec- tosh Creek 33 kilometres northwest and 26.5 kilometres cias were deposited close to vent areas whereas polylithic south of the dated Gravel Creek site is documented by breccias are distal withclasts of the same compositionas the Mathews. He reportsdates of 7.5 and 8.7 Ma, respectively, surrounding volcanic rocks as well as those of previously from those two localities. Rocksof the youngest suite have deposited underlying rocks.The degree of reworking of the not been recognizedin our map area. clasts, and the proportion of underlying rocks, increases away from the ventareas, suggesting most polylithic brec- STRATIGRAPHIC SUMMARY AND cias formed as the resultof slumping down thesides of the FACIES RELATIONSHIPS largely submarine LowerJurassic volcanoes. Following the eruption and depositionof volcanic rocks The oldest exposed rocks of Quesnellia in thecentral of unit 3,a brief periodof mafic volcanism recurred (unit4) QuesnelbeltareMiddletoUpperTriassicsedimentaryrocks and produced alkali olivine basalt flows of limited extent of unit 1, which fromtheir composition (Bloodgood 1987) andapparent subaerial origin. While there is no direct and from that of accompanying tholeiitiic basalts with evidence of these rocks being younger than Sinemurian, MORB-like character, were probably deposited in a back- indirect evidence suggests a Pliensbachian age. or marginal basin, developed crustalby rifting adjacent arc, Comagmatic and, in part, coeval with Early Jurassic to the Triassic margin of continental North America. This volcanism are a number of dioritic stocks and many small sedimentary assemblage which underlies the easternof part intermediate to felsic intrusions which formed in the vent the central Quesnel belt, is also exposed near the western areas of the volcanoes from which unit 3 volcanic rocks margin of the belt, suggesting thatthe volcanic arc which erupted. Cooling ages of these intrusions rable 4-1) indi- during Late Triassic Early Jurassic times is under- formed - cate that emplacement began during uppermost Hettangian lain across its width by sedimentary rocks of unit 1. Camian time but with successively youngerphases being emplaced epiclastic sedimentation was accompanied bythe onset of from Sinemurian throughto possibly the Toarcian stage of mafic alkalic volcanism (unit 2) which continued into the the latest Lower Jurassic, well after volcanism hadceased Norian stage. Eruptive locii were possibly controlled by in the belt. extensional (listric normal?)faults which developed subparallel to the margins of the belt. Early mafic volcanism A period of epiclastic sedimentation within restricted occurred underrelatively deepwatermarineconditions but, basins followed the cessation of volcanism in the central with time, the volcanic pile grew to the point where late Quesnel belt.These sedimentary rocks, dominantlysiltstone mafic volcanic products were deposited in shallow water and fine-grained sandstone and containing a Middle Jurassic and, in part, probably subaerially. fauna, formed an overlap assemblage which now is pre Served in the eastern and western parts the of belt. By late Norian time mafic volcanismhad ceased and a period of erosion of the volcanic piles began and was Further sedimentation in lacustrinesettings and volcan- accompanied byepiclastic sedimentation andthe develop ism occurred duringa period of Eocene crustal extension, ment of limestone reefs in intervolcano basins.In Morehead and which was followed by the widespread eruption of Creek a sectionof mudstone, siltstone and sandstone con- plateau basaltsof Miocene and, locally, younger age.

48 Geological Survey Branch CHAPTER 5 PETROCHEMISTRY

INTRODUCTION The major oxidedata are regarded as high quality and appear to be reliable and reproducible. Analytical results Representativesamplesofigneousrocks,84inal1, were compared by paired replicateanalyses and the precision of analyzed for major oxide and minor element compositions major oxide analyses quoted by the Geological Su~rvey by standard, commercially available, combined x-rayfluc- Branch Analytical Laboratory are shown in Ap.pndi:r H. rescence, atomic absorption spectophotommetry and neu- Minor element analyses, on the other hand, show much tron activationtechniques in order to characterize their variability dueto both differences betweensarnp1e.s from the chemical compositious. The sample suite consists of 59 of same mapunit and inherent problems with analyi:ical accu- the least altered looking rocks collected during this study racy and precision. Minor element data used and recarded from the various, mainly volcanic, map units. The remainingin Table 5-2 are the mean arithmetic values that represent a data represent suitable samples from previousstudies in the composite of various numbers and types of analyses fiom map area, including twenty-two analyses by Bailey (1978) different laboratories. In general, elements with consistent and three by Morton (1976). Theloss on ignition (LOI) from concentrations in the samples analyzed by x-ray floures- these samples is generally in the order of 3%. or less. In cence methods (XRF - barium, strontium, rubidium, yt- addition, 29 analyses by Bloodgood (1987) from rocks of trium, titanium, vanadium and probably zirconiun) have unit la have been included in this study. The data are sufficient accuracy and precisionto adequately demonstrate presented in Appendices F to L. The analytical data are major differences between the map units. Elemtats deter- summarized as average valuesfor the various map unitsin mined by instrumentation neutron activationONAA - rare Tables 5-1, 5-2 and 5-3. All the analytical data are docu- earth and some large-ionlithophile elements, scandiuml and mented in the appendices, including: sample locations and terbium) should be regarded as approximate, especially major oxide and minor element because no comparisonsto higher precision atomic absorp- descriptions (AppendixF); tion or x-ray fluorescence analyses have been made. Ana- analyses (Appendices G, I, J); replicate analyses (Appendix lyticalresults for niobium,neodinium, tantalum and comparison of analyzed and calculated ferrous-ferric H): probably uranium and thoriumare suspect, as are ,myvalues values (Appendix and calculatedCIPW norms (Appen- L); near the analytical detectionlimits of the elements (shown dix K). The data can be compared with, or expanded to in Table 5-2). include, an additional 38 analyses by Bailey (1978) and43 analyses reported by Morton (1976). Further comparisons can be made with similar rocks in British Columbia, the CHEMICAL COMPOSITIONS, Nicola volcanics to the south (Preto, 1979) and Takla rocks DIFFERENTIATION TRENDS, CIPW to thenorth (Bartie, 1993;Nelson and Bellefontaine, 1996). NORMS AND PETROCHEMCIAL ComparableTriassic - Jurassic volcanicarc rocks elsewhere CLASSIFICATIONS in the North American Cordilleraare discussed by Mortimer (1986,1987). PETROCHEMICAL VARIATION Variationsincomposition between samplesare evident; their range within map units is indicated by the standard Analytical data (Appendices G to I) were assembled in dBase tile format and processed by computer to produce deviations of mean values, as shown in Tables 5-1.5-2 and various calculationsand plots. The data for the vicious map 5-3. Differences are generally greater between map units units are summarized in Tables5-1 and 5-2as mcan values, than between samples of the same unit. This allows the with standard deviations. Most plots shownon ligure:; use recognition of map units andtheir correlation on the basis unit-mean valuesto illustrate chemical trends and relation- of composition. Differences are regular and continuous ships in a simpified manner;a few plots utilize all analytical between the map units, as shown on various variation dia- values in order to show the scatter and more dc:tail of the grams, and are consistent with processes of magmatic dif- data distribution. The computer program used :o inil.ially ferentiation andcrystal fractionation. The post-depositional reduce and study thedata is the GSB petrochernicol program oxidationand related changes fromferrous to ferric ironare developed within the Geological Survey Branch by 'D.G. considered to be consistentthroughout the region. The man-MacIntyre. Final calculations and graphic output is .from ner in which ferroudfemc ratios were established is dis- NEWPET, a petrochemical shareware program devehped cussed below. The effectsoflocal metasomatism, mainlyby I987 to 1991 byDaryl Clark, Memorial University of potassium and sodium,are not evident in thin section or in Newfoundland. staining tests and are, hopefully, negligable in the selected Crystal-liquid fractionation processes in Quesnel basal- least-altered samples. Nonetheless it is possible that some tic arc magmas canbe illustrated by any number of Harker- sodium was introduced the by interactionbetweentheisland type variation diagrams that depict fractionation indices arc rocks and seawater. (Cox ef ai., 1979). Bailey (1978) effectively utilized the

Bulletin 97 49 TABLE 5-1 AVERAGE MAJOR OXIDE COMPOSITIONS

MAP *N Si02 TiO, Alto, FeO-T MnO MgO CaO NazO KzO P205 FeO Fe2O3 UII Tots1 COz K DIF INIT Vrl.,I"","> I."._mmPY 1A 1 46.92 0.75 16.64 8.39 0.18 5.68 13.06 1.76 1.32 0.22 5.52 2.25 5.28 100.20 1.81 10958 24.1 2A 13 47.70 0.66 13.17 10.47 0.19 7.70 11.23 2.54 2.09 0.34 7.48 2.16 3.43 99.52 0.64 17350 32.7 2A SD 1.26 0.11 253 1.19 0.02 2.33 2.37 1.28 1.52 0.12 1.08 0.11 0.94 -- 0.81 - ". 2Anr, 5~~ 56133 6.13 15.99 9.88 0.17 5.62 8.05 3.33 2.07 0.31 6.88 2.13 3, 99.48 0.32 17184 42.2 MDSD 1.21 0.12 0.31 1.22 0.02 0.46 0.66 0.32 056 0.04 1.07 0.12 0.06 -- 0.14 - - 2B 16 47.51 0.70 13.04 11.27 0.20 7.47 10.29 2.97 2.61 0.57 8.08 2.20 3.24 99.87 0.30 21667 37.2 2B SD 1.10 0.08 1.75 1.27 0.03 1.77 1.99 1.15 1.51 0.10 1.03 0.08 0.83 --- 0.35 --- ." 2C 5 49.03 0.78 16.59 10.12 0.21 5.02 8.60 4.02 2.55 0.47 6.92 2.28 2.95 100.34 0.22 21169 45.6 2C? SO1.03 0.07 2.061.55 1.32 2.43 0.141.79 0.03 1.12 1.88 0.990.14 -- 0.30 --- ." 2D 4 48.05 0.73 1251 11.83 0.22 9.25 10.41 2.78 1.85 0.39 8.51 2.23 2.83 100.85 0.02 15358 32.8 2D SD 1.61 0.18 3.14 1.71 0.02 3.08 2.98 1.17 1.00 0.13 1.31 0.18 1.40 -- 0.03 --- ." 2E 4 48.36 0.74 15.71 9.72 0.21 4.77 7.33 4.09 3.40 0.53 6.96 2.13 4.66 99.52 0.24 28225 51.1 2!3 SD 2.57 0.08 2.29 2.05 0.02 1.54 2.95 1.03 1.55 0.10 1.97 0.08 1.37 -- 0.16 --- " 46.6 2G SD ~3.6 0.11 0.54 1.37 0.05 0.79 3.27 1.21 1.83 0.19 1.15 0.11 0.23 --- 0.06 -- ." 3 3 53.92 0.65 17.39 7.20 0.19 2.26 5.76 5.09 3.44 0.34 4.54 2.15 3.32 99.56 0.99 28557 64.2 3 SD 4.56 0.17 1.14 1.75 0.05 1.25 2.35 2.07 1.22 0.09 1.48 0.17 0.75 --- 0.46 - " 3A 9 50.82 0.82 17.36 9.94 0.22 3.81 7.05 4.65 297 0.40 6.29 2.32 3.04 101.08 0.07 24655 53.9 3A SD 3.26 0.13 2.02 1.61 0.02 1.11 1.71 0.76 0.91 0.12 1.33 0.13 1.13 -- 0.W - ." 3B 2 48.80 0.85 18.45 10.59 0.18 4.29 7.67 3.14 3.60 0.30 7.17 2.35 3.37 101.24 0.16 29885 46.1 3B SD 2.40 0.04 0.07 1.70 0.09 1.08 1.48 1.64 0.46 0.01 1.58 0.04 0.70 --- 0.00 --- - 4 3 48.93 0.83 15.92 11.64 0.20 4.78 8.08 4.42 2.17 0.48 8.22 233 3.51 100.96 0.16 18014 46.7 4 SD 1.31 0.11 1.50 1.04 0.03 0.89 0.28 0.42 1.17 0.08 0.82 0.11 0.50 --- 0.00 --- " 7 IO 51M 0.79 16.05 9.56 0.18 5.24 9.26 3.01 2.60 0.37 6.52 2.29 1.78 99.84 0.25 21584 42.0 ." 8257.01 0.84 15.34 7.78 0.13 4.33 5.48 4.41 1.29 0.18 4.90 2.33 2.98 99.77 0.65 10709 54.7 8 SD 3.85 0.29 2.00 268 0.01 0.70 0.60 0.50 1.29 0.06 2.16 0.29 0.06 _.. 0.69 -. ." 10 2 10 54.91 0.71 14.71 5.57 0.15 3.29 6.32 3.43 3.30 0.48 3.03 2.21 6.49 99.36 4.65 27395 59.8 10 SD 5.20 0.42 4.01 0.37 0.06 3.03 0.93 0.81 1.42 0.42 0.05 0.42 3.18 - 4.07 ." " loc 1 4554 1.11 11.43 9.11 0.16 8.86 8.77 2.63 0.96 0.89 5.85 2.61 8.94 98.40 5.60 7969 31.4 11 1 48.55 2.04 13.06 12.71 0.17 8.43 8.92 2.91 0.77 0.33 8.25 3.54 1.88 99.77 1.71 6392 30.1 MAB lM9 49.84 0.68 13.78 11.23 0.19 9.65 10.43 2.10 1.73 0.35 8.14 2.18 0.00 99.98 0.00 14359 28.3 " " MAB IASD ~~..3.w 0.17.~.~ 1.77 1.55 0.04 3.72 2.59 1.43 0.95 0.08 0.00 0.w~~~ 0.00 ~~~~ 0.00 -_ ZA to E 47 13.950.7048.14 10.70 0.20 7.00 9.89 3.08 2.40 0.45 2.207.60 3.33 99.84 0.36 19945 38.4 2AlaESD 1.58 0.11 2.13 1.33 0.03 1.93 2.30 1.14 1.40 0.12 1.15 0.11 0.93 -- 0.43 -- ". 3BAnB14 51.20 0.79 17.52 9.19 0.21 3.55 6.86 4.53 3.16 0.37 6.04 2.29 3.15 100.53 0.99 26275 55.0 3BAnBSD 3.59 0.15 1.69 1.90 0.04 1.27 1.79 1.27 0.91 0.11 1.54 0.15 0.96 - 0.46 - "

TABLE 5-2 AVERAGE MINOR ELEMENT COMPOSITIONS ------mEX RI - - 386 270 ------141 31 I 907 18.0 4091 0.1 " 65 43 14248 28.101504 818 31.118 296 269 51 0.4 90.7 02 16 36 I 542 14.2 3917 0.1 10.0 9.6 61 11350 1484 34.W IW8 - --82255-----2932 - 685 124 4373 0.7 " 9.0 80 17184 1353 46.60 922 2141.933 260 0.954 1.1 17 0.1 41 50 4 32.8 0.2 2.50.5 1.2 I 933 12.8 4237 0.7 20.0 10.4 62 21663 2488 37.20 865 €4 0.1 10 1953.00.233 25 0.1 9 51 5 10.0 2.3 0.1 2.1. I5 I Icm8 21.0 4672 0.8 - 14.7 119 21165 2051 45.w 5w 17 29 1050.328557 1.0 147 490.2 2 403 0.1 - 1.1 0.8 553 2 115 4359 0.7 9.0 45 n 15355 1102 32.80 2E 1322 430.934 242 52 0.2 2.0 14 0.1 14 63 4 19.6 0.6 0.1 1.8 1.4 1 595 15.7 44% 0.7 - 10.0 18 28220 2313 51.10 2G 597 r) 3.2 221 334 22 1.1 1.4 14 0.4 12763 4 21.8 0.1 0.1 2.0 22 61921.3 3 4933"" 0.7 13.0 5.0 80 18841 1521 46.w 3 10% - - 10148~~~~~-6% - -. 1.6 - .- 16.0 4 821 25.0 3911 0.8 9.1 108 10707 786 54.70 3nMB 1298 34 1.0 146 9 30 0.20.2 8 0.1 12 56 4 9.5 1.1 0.1 1.7 11.0 26.3151 3 4728 0.1 9.8 114 28552 1484 M.20 3A Ism 34 1.0 5 143 30 0.2 0.2 8 0.1 5421 4 9.5 0.1 0.1 1.7 1.0 I 542 9.0 4918 0.8 10.0 132 26228 1484 55.w 3B ------. -. -. -. -. ______-..- -. - - _. so9091 0.8 .--. - 24651 I746 53.10 4 11W 43 0.1 30546 5 02 112.0 0.1 4 44 4 19.0 0.10.1 1.52.4 I 955 16.0 49510.9 .- 2988015.061 13W 46.10 8 831 - - 124 164 - _. -. - - 25 21 _- - - - _. - _.23.0 427 5% 0.8 - 12.5 120 18011 2095 46.70 1 10% 25 1.5 104 281 46 1.0 121.2 0.3 IO 64 36.70.3 3 0.0 1.8 1.2 19.4751486313.00.8 2 50 2158066 1615 42.M 10 28~- - 170138 - - -. - - 62 73 - -. 1.1 - - 16.5 s 903 22.5 42540.7 ... 9.0 161 27390 ms 59.80 1oC 5457 - - 520 221 ------. I60 20 ------. IW4 665523.0 1.1 - 9.0 164 7968 3884 30.10 11 190 - 10.3191297 - .- -. .- -- 7141 - -. 0.1 - - 10.0 1 481 22.0 12219 20 - 15.0 I24 6391 1440 31.40 2A.Z 935 r) 10.3 220 272 Y 0.6 1.2 14 0.1 48 44 3 34.6 0.4 0.4 1.9 1.0 I 160 14.1 4M19962 711961 9.913.8 0.1 -

50 Geological Survey Branch Ministry of Employment nnd lnveshnenr "

TABLE 5-3 CJPW NORMS FOR MAP UNIT AVERAGECOMPOSITIONS __

AVE AVF, AYEAVE AVE AVE AVE AVE AVE AVE AVE AVE AVE AVE AVE AVE hvB AVE Mapunit 1A 2C 2A 2B 2AJW 3 W2G 2E 8 7 3A4 3B 10% IOb 1% I1 OXIOSS AS DEYERMND Si453.92 52.5548.36 48.06 49.03 47.51 50.33 47.70 49.78 ~0.8248.5545.5458.5951.23 57.01 51.00 48.93 48.80 0.69 0.66 0.73 0.70 0.78 0.73 0.74 0.65 0.65 0.82 0.85 0.83 0.79 0.840.79 0.83 0.85 0.82 0.65 0.65 0.74 0.73 0.78 ?IO*0.70 0.73 0.66 0.69 1.01 0.41 1.11 2.04 13.73 13.17 15.99 13.04 16.59 12.51 15.71 16.76 17.39 17.36 18.45 15.92 16.05 15.34 11.87 17.54 11.43 13.0611.4317.54 11.87 15.34 16.05 15.92 Alto, 18.45 17.36 17.39 16.76 15.71 12.51 16.59 13.04 15.99 13.17 13.73 2.16 2.23 2.20 2.28 2.23 2.24 2.15 2.15 2.32 2.35 2.33 2.35 2.32 2.15 2.15%Os 2.24 2.23 2.2811.23 2.20 2.23 2.16 229 2.34 251 I91 2.61 354 7.48 6.88 8.08 6.92 8.51 6.87 5.60 4.54 6.29 7.18 8.22 6.52 4.90 2.99 3.06 5.85 8.255.85 3.06 2.99 4.90 6.52 8.22 7.18 6.29 4.54 pso5.60 6.87 8.51 6.92 --8.08 6.887.48 0.19 0.19 0.17 0.20 0.21 0.22 0.21 0.19 0.19 0.22 0.19 0.20 0.18 0.13 0.18 0.20 0.19 0.22 0.19 0.19 0.21 0.22 0.21Mno 0.20 0.17 0.19 0.19 0.110.17 0.16 0.19 9.55 7.70 5.62 7.47 5.02 9.25 4.77 4.68 2.26 3.81 4.29 4.78 5.24 4.34 5.43 1.15 8.86 8.438.86 1.15 5.43 4.34 5.24 4.78 4.29 3.81 2.26 4.68 4.77 9.25 5.02 Mgo7.47 5.62 7.70 9.55 GO 8.928.058.77 11.23 5.66 10.52 6.97 5.48 9.26 8.08 7.67 7.05 5.76 10.297.42 7.33 10.41 8.64 Ne9 209 254 3.33 2.97 4.02 2.78 4.09 3.72 5.09 4.65 3.14 4.42 3.01 4.41 2.85 4.W 2.63 2.91 KP 1.71 2.09 2.07 2.61 255 1.85 3.40 2.27 3.44 2.97 3.61 2.17 2.60 1.29 4.31 2.30 0.96 0.77 P9, 0.34 0.34 0.31 0.57 0.47 0.39 053 0.35 0.34 0.40 0.30 0.48 0.37 0.18 0.78 0.18 0.89 033 co, 1.81 0.64 032 0.30 0.22 0.02 0.24 0.04 0.99 0.07 0.W 0.16 0.23 0.66 753 1.77 5.60 1.71 Lo1 5.28 3.43 3.W 3.24 295 284 4.66 245 332 3.04 3.37 351 1.78 298 8.74 424 8.94 1.88 T& 9.89 98.70 98.71 98.88 99.43 99.77 98.91 98.79 w.06 99.75 1w.18 99.87 99.08 99.20 98.80 99.23 97.75 98.85 OXIDESREC~VOLATILEFREE Si4 49.92 33.08 525954.52 51.2949.59 50.83 49.68 56.2956.88 59.2552.4050.78 50.42 52.56 61.a 50.0751.28 EO , 0.69 0.69 0.76 0.73 0.81 0.76 0.79 0.68 0.69 0.85 0.88 0.86 0.81 0.87 1.12 0.43 1.25 2.10 1.25 0.43 1.12 0.87 0.81 0.86 0.88 0.85 0.69 0.68 0.79 0.76 0.81 0.73 0.76 0.69 0.69 EO, 13.78 13.84 16.70 13.65 17.21 12.92 16.67 17.40 18.16 17.93 19.06 16.53 16.50 15.94 13.18 18.47 12.87 13.4712.8718.47 13.18 15.94 16.50 16.53 19.06 AIS,17.93 18.16 17.40 16.67 12.92 17.21 13.65 16.70 13.84 13.78 11.24 2.27 2.33 2.30 2.36 2.302.36 %O,2.30 2.33 2.27 11.24 3.65 2.94 2.01 2.79 2.43 2.35 2.42 2.43238 2.40 2.25 2.23 pso 8.78 7.17- 8.44 7.19 7.84 730 4.755.81 650 8.517.416.59 3.22 8533.32 5.09 6.71 0.19 0.20 0.18 0.21 0.22 0.22 0.23 0.20 0.20 0.23 0.19 0.21 0.18 0.14 0.12 0.20 0.18 0.180.18 0.20 0.12 0.14 0.18 0.21 0.19 0.23 0.20 0.20 0.23 0.22 0.22 Mno0.21 0.18 0.20 0.19 Ma0 5.19957 7.80 5.87 8.07 954 4.86 5.06 394238 5.39 4.96 4.43 451 1.21 6.03 998 8.69 10.55 11.78 8.41 10.75 8.89 10.73 7.80 7.73 6.03 7.28 7.92 8.387.92 7.28 6.03 7.73 7.80 10.73 GO8.89 10.75 8.41 11.78 10.55 9.209.88 9525.96 7.74 5.69 Na,O 2.09 2.67 3.47 3.10 4.18 2.86 4.35 3.85 5.31 4.81 3.25 458 3.09 4S8 3.16 4.21 2.96 3.W KP 1.72 2.19 2.16 2.74 2.64 1.92 3.60 2.36 3.64 3.08 3.73 2.26 2.67 1.35 4.79 242 1.08 0.79 Pa<.. 0.35 0.36 0.33 0.60 0.49 0.40 0.56 0.37 0.35 0.42 0.31 050 0.38 0.19 0.87 0.19 1.W 0.34 Tanl lW.W 1W.W 1W.W 1W.W 1W.W lW.W lW.W 1W.W 1W.W 1W.W lW.W 1W.W 1W.W lW.W 1W.W 1W.W 1W.W lW.W cipw NORM VOIATILE FREE Q 0.19 OW 0.74 0.W 0.W 0.W 0.00 0.37 0.W 0.48 OW 0.W 0.99 8.06 1.50 12.99 0.00 0.W n 10.15 12.97 12.78 15.78 15.63 11.32 21.26 13.93 21.29 18.20 22.W 13.33 15.76 7.92 28.28 14.31 6.39 4.69 ab 15.73 16.41 27.49 15.10 23.89 14.74 21.74 32.55 39.50 27.85 20.7s 26.98 23.11 38.73 26.n 35.62 25.05 25.38 a0 23.12 19.29 23.61 15.21 m.42 16.75 15.38 23.25 15.10 18.43 26.45 17.90 23.29 19.00 7.64 24.35 18.64 m.94 115 1.07 3.36 1.03 6.05 619 5.14 8.13 0.W 2.91 6.78 3.92 6.38 1.64 0.W 0.W 0.03 0.W 0.00

s+ 0.W 0.00 0.00 0.W 0.W 0.W 0.W 0.W~~ 0.W 0.27 0.00 0.W 0.W 0.00 0.W 0.00 0.00 0.W di 13.m29.8921.91 n.92 16.83 n.53 10.3716.15 10.35 12.35 8.94 16.93 17.51 650 19.82 3.32 19.05 18.12 k 0.W 0.00 0.W 0.33 0.00 0.W 0.00 0.00 0.00 0.00 0.00 0.W 0.00 0.W 0.W 0.W 0.W 0.00 hY 11.83 0.20 7.97 0.00 0.W 5.72 0.W 11.69 1.57 1.31 0.W 0.W 5.53 14.24 7.84 5.27 17.52 16.73 01 9.85 12.47 7.76 13.53 IO.% 13.16 11.13 2.51 3.92 8.42 12.58 12.23 6.37 0.03 0.00 0.W 4.41 4.07 ml 3.18 329 3.38 3.33 3.43 3.34 3.45 3.24 3.26 3.35 3.52 3.50 3.41 3.52 4.04 2.92 426 5.29 il 1.31 1.31 1.45 1.39 1.54 1.44 150 1.29 1.30 1.61 1.67 1.63 1.54 1.65 2.13 0.82 2.37 4.W ap 0.81 0.84 0.76 1.40 1.13 0.93 1.32 0.85 0.82 0.97 0.73 1.15 0.89 0.43 2.02 0.44 234 0.79 AN= 46.5958.1361.92 54.69 42.2341.7753.7149.22 -31.92 - 41.61 -58.15 - 40.85 -51 06- 32.29 -22.19 - 40.60 .-42.67 .- 45.21 ~CIPWnanrcalculll~b~GSBprogmmfDonM~~l~~~199292) ~~Avrmgrr(AVElcak~~~df~r~~~~~~~~plur29~yl.lyruofunalAfmmBlwdgood,1987 ***Fep, wk~fxunhlA=Fc>O, Total

differentiation index @.I.) of Thomton and Tuttle (1960) have little variation. The soleexception to simple, wntinu- and we continue its use in this report. The differentiation ons trends is alumina which appears to have .a bimodal index is expressed as: D.I. =normative Q + Or + Ab +Ne distribution. The two populations showlittle variation :From + Ks + LC. Major oxide trends(Figure 5-1) show the least concentrations either around 13% or 16to 17%. The larger differentiated rocks are basalts of the oldest and youngest amounts of alumina are present in units la, 7 and the more basalt units units la and 11. The main arc basalts, unit 2, differentiated subunits of unit2 compared to mks of units show progressive evolution andincreasing differentiation in 2a. 2b, 2d, 10 and 11. The rocks with the greatcr alumina magmas from earliest to the latest subunits 2a to 2g; the content tend to containlarger amounts of modal plagioclase subaerial basalts of unit 4 and the coeval intrusive suite of and hornblende in addition to ubiquitous pyroxme. These diorite to syenite are similar. The most differentiatedrocks chemical differencesare evident in terms of silica saturation are those of units 3, the younger quartz-bearing intrusions as indicated by calculated norm compositions, discused of unit 8 and the Eocene volcanics of unit 10.The differen- below. tiation trends ofthe major oxidesare normal andconsistent Minor element concentrationsplotted againr.t differen- with fractional crystallization. Increases in differentiation tiation index (Figure5-2)showsimilardistinctions between index are largely due to increases in KzO, NazO and a the map units.Similar behaviour is shown by barium, nlbid- decrease in CaO (with attendant decreases in FeO* and ium, strontium, yttrium and zirconium which rise in more MgO). Potassium showsconsiderable variation, especially differentiated rocks, and chromium together with nickel in the more felsic rocks. Silica, titanium and phosphorus which decrease. Vanadium has two concentration levels -

Buiierin 97 5I British CoIumbia

15 5 4 10 3 2 1 0 4

3 5 2 03 1

0 CaO Ti09 2.: L 2 10 1.f 1 .5 5 0 .7 18 .6 16 .5 .4 14 .3 - 12 .2 08 010b .1 10 J OL J 20 30 40 50 60 70 20 30 40 50 60 70 Dl Dl

Figure 5-1. Differentiation index @.I.) of Thornton and Tuttle (1960) with D.I. = nonnative Q+Or+Ab+Ne+Ks+Lc plotted against Quesnel mapunit average majoroxide values.

52 Geological Survey Branch Ministry of Employment and Investment "

30 03a Y I 21 00 25 2600r1600 - 3a - 4 *2e 3,3$,3b 20 I100 *2b ?Cob$$ *la 04 600 - 026 29 15 2e *2b - 011 *2a/2d *2d I 100 10 07 010 70 -Rb de - 60 3 3,3a,3t '29 "I - o2b 02c %a 30C 50 *2d *4 40 - *2a - *la *2a/Zd 30 2c *lob 08 2oc 011 20 - *8 O3 3,3&3b 10 t 011 *3a,,10 1oc 0 *lob 1000 Sr *2c *4 125 .la o2b 010 03 100 800 75 *2a I 50 25 0 160 - zr 'lob YO .2d Cr 140 - 3a *I1 600 120 - 2S.8 *lob 03 100 - *2e 400 80 - 02d 2g*2a/2d 3,3a,3b 2a. 02b *7 04 200 60 - .1 a 40- 0 20 30 40 50 7060 20 30 40 50 60 70 Dl Dl

figure 5-2. Differentiation index (DL)of Thornton and Tuttle (1960) with D.I. = nonnative Q+Or+Ab+Ne+Ks+Lc plotted against Quesnel Mapunit average minor element values.

Bulletin 97 53 BrifishColumbia

F I I

Si02 % Map Units

_I Figure 5-3. AFM diagram showing fields for Quesnelunits la, 2 and3.BasaltsoftheQuesnelislandan;necalcalkaline.Theoldest hasalts of unit la appear to be transitional from tholeiitic (subalkaline) to calcalkaline. Boundariesanddifferentiationtrends me from bine and Baragar (1971). either 150 ppm or around 275 ppm. Differences between map units are recognizableaccording to their minor element abundances.ThemainarcbasaIticunits2,3and4aresimilar but their minor element concentrations are distinct from those of units la, 10 and 11. The oldest basalts of unit la Ne’ Ab Q‘ contain the smallest amounts of most minor elements except L Figure 54.Normative coipositi&, CIPWno&forall ikyn for yttrium and nickel which have relatively high concen- Quesnel samples.A. - Composition of basalts on alkali-silica plot trations. The Eocene biotite-bearing flows of.unit 10 are with iddinorm compositions of Cox ef a!. (1979). Quesnel markedly enriched in barium, strontium, rubidium, zirco- rocks are dominantly silica undersaturatedwith normative OI+Ne. nium, chromium and nickel. The Miocene plateau basalts B. - Normative Ne’-Ol’-Q’ indicating predominantly alkaline are depleted in barium, strontium, rubidium and vanadium compositions for Quesnel basalts. but enriched in zirconium nickel. are yttrium, and A vast majority ofthe rocks are silica undersaturated, 60 of The AFM diagram (Figure 5-3)shows some separation the 84 rock analyses provide normativeolivine and of fields for volcanic of the major map unitsla, and rocks 2 nepheline. Of the remainder, five are silica saturated with 3.Allrocksinunit3andmostinunit2arecalkalkalinerather normative hypersthene and olivine and the remaining five than tholeiitic in character; of unit 4 overlap these rocks samples are silica oversaturated with normativequartz and fields andare not shown in figure. The compositions of the hypersthene. The undersaturatedrocks contain up to 14.7% the volcanic rocks shown on Figure are minunicked by 5-3 normative nepheline and as much as 18% olivine; three of the data of Bailey (1978) and Morton (1976) fromsimilar thesamples haveasmall amount ofnormativeleucite. These rocks in the study area but their not shown onthe data are basaltic rocks are alkali basalts in the sense of Yoder and figure. Rocks of unit la appear to be transitional tholeiitic Tilley (1962). The ten alkalic intrusive analyzed are that follow a primitive Hawaiian basalt fractionation rocks rocks evenly divided betweensilica undersaturated and (slightly) trend. Some of the magnesium and iron these in rocks might silica-saturated rocks. The Eocene volcanic rocks are silica have increased due to metasomatism associated with chlo- over-saturated according to their norms, as would be ex- rite alteration (Bloodgood, 1987). Overall, the distinction pected for these quartz-bearing rocks. The Miocene tholei- between unit la and the other rocks shown in the AFM arc itic basaltic rocks are silica saturated and have normative diagram and in other discriminant plots (see discussion hypersthene andolivine. The relationships showing alkali- below) seems fundamentally valid.The sample of Miocene silica ratios of the analyzed sample suite compared with plateau basaltis the other lava type that falls in the tholeiitic predicted, ideal normative character and degree of silica field. saturation are shown on Figure 54a. A plot of normative Ne’-Ol’-Q’ places the majority of Quesnel volcanic and CIPW NORMS arc intrusive rocks in thealkaline field (see Figure 54b). Only Calculated CIPW norms for typical rocks, as indicated a few samples from units 1 and 2g fall in the subalkaline by map unit average values, are shown in Table 5-3 and field; it is occupied bythe rocks of unit la and the younger norms for all the analyzed rocks are listed in Appendix M. rocks of units 8,lO and 11.

54 Geological Survey Branch Ministry of Employment anrilnvesheni

The oxidation state of iron in the analyzed rocks and used in the normative calculations was assigned a standard I A 2e oxidation state using the convention of Irvine and Baragar ’*I 3 (1971).Accordingtotheirconventiontheironreportdfrom the laboratory as Fez03 (FeO* or Fe@) was consideredto 0, be approximately Fez03 = Ti02 + 1.5 with FeO* = FeO + zm Fe2O3* 0.8998 and Fez03* = Fez03 + FeO* 1.11 135. The + convention used resulted in an overall FezOdFeO for the data set of about 0.31. This is fairly close to the empirical 3 4- value of about 0.39 determined by Morton (1976) and the 0.35 value used universally by Bailey (1978). The value used appears to be appropriate or still possibly slightly too oxidized, based on the distribution of compositions in the I 1 ideal normative alkali-silica saturationfigure (Figure “4). I 40 50 60 A less oxidized value would make the sample suite appear even moresilica undersaturated. Femclferrous ratios determined in this study from twelveanalyses of typical Quesnel arc rocks (Appendix N) indicate a greater degree of oxidation thanthe calculated values used and those of Morton and Bailey. The measuredFezOfleO is approximately 0.8 for the Triassic-Jurassic volcanic and intrusive rocks of the Quesnel belt.This highly oxidized assemblage is thought to represent post-depositional oxidationof rocks in the volanic belt.

ALKALINITY ALKALIC BASALTS AND i SHOSHOMTES TERMINOLOGY FOR Figure 5-5. Classification of Quesnel basaIts on the basis,of total - alkalis, potassium and silica contents.A.- Total alkali-silica(TAS) QUESNEL ARC ROCKS plot with boundaryof Irvine and Baragar (1971) showing predominance of alkalic compositions. Fields encompass all Alkaline rocks maybe defined @%ton and Upton, 1987, analysesfromunitsla,2and3:unit4analysesareco11tainetiwi~n page ix)as those with higher concentrations ofalkalis than the field for unit 2. B. Potassicalkalic rock classification of can beaccommodatedby feldsparalone. Theexcessis taken Peccerillo and Taylor(1976) showing dominant shashonik series up in felspathoids, sodic pyroxene, sodic amphibole and affiliationof Qnesnel arcbasalts. Map-unit averagevaluesplotted; other alkali-rich phases. The rocks are undersaturated in fields encompassing all analysesfrom units 2 and 3 are shown. silica and alumina with respect to alkalis and will have nepheline andor acmite (or leucite) in their norms. More commonly, alkaline rocks are defined simply in terms of theiralkali and silica content. The analcite-bearing, nepheline-normative basaltic arc rocks of the central Ques- ne1 belt qualify according to both of these criteria. Total alkalis-silica diagrams(TAS), one of the simplest yet most effective indicators of chemical associations and the basis for a number of classifications, showall data and unit average values on Figure 5-5.The compositions reveal a pronounced alkaline character with the exceptionof unit la and the plateau basalt of unit 11 which are subalkaline. According to the TAS diagram and classificationsof Zanet- tin(1984)andLaBasetnl.(1986)theQuesnelbasalticrocks are mainly basalt, basaltic trachyandesite and trachyandesite. Lass commonlypresent are themore basic and alkali-enriched variants. They range in composition from picrobasalt to basaltic andesite and basalt trachyandesiteor include tephrite (normative olivine percent) and basanite (normative olivine 10%) and their more differentiated types - phonotephriteand tephriphonolite. Alternatively,accord- Figure5-6.NormativeAb’-An-OrpIotforQuesnelrraparearocks; ing to the classification of Cox er nl. (1979) the (alkaline) Ab’ = Ab+5BNe. According to this plot, Quesnelracks are evenly basaltic volcanic rocks, if considered‘normal’, that is, non- divided between sodicand potassic suites.

” Bulletin 97 55 British Columbia

potassic rocks, are a suite of basalt-hawaiite-mugearite to high potassium with 1.8% KzO at 50% Si& and trachybasalt, with lesser trachyandesite, benmoriteand 2.5% K20 at 53% SiOz and KzOiNazO values phonolitic tephrite (Figure 5-5). However, the rocks fall in >0.6% at 50% Si02 and >1.0 at 55% Si02 the field of potassicalkaliie rocks according to a number of * steep positive slope on KzO versus Si& at 47% conventional discrimination diagrams suchas the Ab’-An- Si02 but zero or negative slope at 57% SiOz Or (Figure 5-6) and KzO/NazO versus Si& (Figure 5-8). high but variable&03, commonly 14 to 19 % Therefore theclassification and terminology using schemes low iron enrichment(flat trend on AM) alkalicpotassicrocks areappropriate as discussedbelow. fa low Ti02 (4.3 %, commonly 4.0 %) The basaltic rocks have a relatively high content of * high FezOJFeO alkali metal oxides and(most) are clearly alkaline or ‘alka- (>OS) lic’, silica-undersaturated rocks of mafic composition. The * enrichment in Ba, Sr, Rb, Pb, light rare-earth ele- younger, analcite-bearing rocks of unit 4 and some ofthe ments (LRJZE), in accord with high potassium;also unit 2 and 3 subunits are strongly sodium-enriched com- commonly high copper, platinum group elements, pared to the other basaltic units. The overall potassium to phosphorusand, locally, carbon dioxide and sodium ratio reveals that the rocks are more sodic than fluorine. potassic. Nevertheless they lie in the ‘potassic’ field on normative Ab’-An-Or plots as shown by Bailey (1976) and Under the shoshonite series classification,the rocks of this study (Figure 5-6). A similar alkaline potassic designa- units 2 and 4 are mainly absarokites and those of unit 3 are tion is given the sample suite according to the alkali ratio absarokite to shoshonite. The rocks of units la, and the classification scheme of de Rosen-Spence (1992). If the Tertiary units IO and 11 are calcalkaline to high-potassium KzO versus Si02 variation diagram for potassic rocks of calcalkalineseries (Figure 5-Sb).The similar schemeof Gill Peccerillo and Taylor (1976) is used, the Quesnel arc vol- (1981) utilized by Gill and Whelan (1989)provides further canics are part ofthe shoshonite series, (see Figure 5-5b). subdivisionsinto medium and high-potassiumcalcalkaline The term ‘shoshonite’ originates from rock types re- (MK and HK CA) and low, medium and high-potassium ferred to by Iddings (1895) as the absarokiwshoshonite-ba- shoshonite fields (LK,MK and HK Sh; see Figure 5-7). A nakite series. Theterminology was re-established and further distinction can be made withinthe shoshonite suite redefined by Joplin (1968, and references therein) as the on the basis of potassium and sodium contents; the most shoshonite magma series and later as the shoshonite asso- basic alkaline rocks with elevated sodium content in the ciation. The shoshonite association consists of assemblages Quesnel arc (Figure 5-8) can be referred to as ‘tristanites’ of alkaline rocks of maficto intermediateaspect. Chemical according to de Rosen-Spence (1992). characteristics of the shoshonitic association according to Momson (1980) with modifications by Mutschler e? al. *ma (1987).Gill and Whelan (1989), Rickwood (1989) and Shoshonite Mutschler and Mooney (1993) are: 1.4 c basaltic members are nearly silica saturated and can contain up to 5% normative quartz or nepheline high total alkalis (NazO + KzO), generally >5%;

50 60 70 Si02 (%)

imre 5-8. Alkaline sodicand alkaline wtassic suites, diagramo deRosen-Spence (1992). Field of aikaline potassic &ks of ‘eisIanite’ association ofGongh Island, Tristan da Cunha shadedI. Figure 5-7. KzO versus Si& plotsof Gill (1981). Quesnel basal& Shoshonitic suites have laq& K20/Na20 and commonly plot range from calcalkaline to shoshonitic compositions.H =high, M outside this diagram. Quesnelmap unit average valuesare shown; = medium, L = low, K = potassium, Sh = shoshonite and CA = the rocks are relatively sodium-rich basaltsof the alkaline potassic calcalkaline. association.

56 Geological Survey Branch Minisrry ojEmpbyment and Investment

Figure 5-11. Tfi minor element discrimination plot for various tectonic settings after Pearceand Cann (1973). Quesnel map unit average values plotted. MnO 10 P,O, 10 CAE = Calcalkaline basalt OIA = Ocean-island andesite IAT = Island arc tholeiite MOR6 = mid-ocean-ridge basalt L Oil = ocean-island tholeiite Figure 5-9. Ternary plot of minor oxide anaIyses with fields f or various tectonic settings after Mullen (1983). Quesnel map-m lit average values plotted, shadedfield shows spread for all analyvXI samples. r Ti/ 100

I - Figure 5-12. V/% minor element discrimination plotof Shervais A (1982). Data for all analyzed Quesnel samples.

Zr Y*3 D WPB = within-plate basalt B: OFB = ocean-floor basalt A, B: LKT = low-ptassium tholeiite B, C CAB = calcalkaline basalt Figure 5-10. Ternary minor element tectonic discrimination plot after Pearce and Cann (1973). Quesnelmap unit avaerage values plow shaded area shows spread for all analyzed samples. Figure 5-13. Comparison of some minor element contents of QuesnelandequivalentNicolaGroupbasalts;figurerdifeifrom Monimer (1987). Quesnelmapunit average values plotted.

” Bulkfin 97 57 British Columbia

MULTI-ELEMENT VARIATION AND analyses. The application, use effectivenessand of discrimi- MINOR ELEMENT DISCRIMINATION nation diagrams has been reviewedextensively by Erdman (1985). DIAGRAMS In this study, geological mapping of the Quesnel vol- Multi-element discrimination diagrams pioneered by canic rocks bas led us, and others before us, to the interpre- Pearce and Cann(1973). Miyashro (1975). Floyd and Win- tation that they were deposited in a (calc)alkaline volcanic chester (1975), Pearce (1982) and others, are commonly island arc. It is, therefore, reassuring that at least some of used to identify the tectonic setting or interpret the origin of thediscriminationdiagramssupportthisconc1usion.Aprob- basaltic magma. More importantly,minor element dia- lem frequently encountered is that the use of the minor grams, especially plots of elemental ratios and normalized element discriminant diagramsrequires analytical accuracy multi-elementplots(Pearce,1983,HawkesworthandNorry, and detection limits that are simply not provided by com- 1983) can provide an effective basis for comparison be- mercially available, large-volumestandard analyticalfacili- tween similar rock suites. These plots canshow significant ties. A number of the effective diagrams are illustrated on contrasts not always evident from major oxide and other Figures 5-9 to 5-16 as examples. The most reliable data are from the suite of immobile minor elements - titanium, yttrium, zirconium, as well as Unit 2 I vanadium, and the minor element oxides MnO, Ti& and P2os. Plots (Figures 5-9 to 5-12) clustering of the Quesnel basalts into fields for calcalkaline arc rocks; the transitional tholeiites of unit la in many cases can be distinguished as their analysesplot outside the main basalt unit clusters. The Eocene and Miocenevolcanics generally fall in fields separate from the other rocks and are distinct. Comparison of the minor element contents of basalts with studies by Mortimer(1987) of the similar Nicola rocks from southern British Columbia reveals a similarity between the Quesnel basaltic units and the high-potassium calcalkaline to shoshonitic rocks of his map unit 1 (Figure 5-13). Quesnel basalts have barium and vanadiumcontents that are distinct from calcalkalinerocks andare intermediate between the subalkaliie low to medium-potassium rocks and the enriched shoshonites of the Nicola Group. All the SaRbTh U K NbLaCsSrNdSmZrWliEu Tb Y Yb Lu Quesnel basalts and Nicola unit 1 rocks appear to be de pletedin niobium compared to Hawaiian lavas and Figure 5-14. Chondrite-normapzed extended minor element plot (bulk earth nomWdiagram or'BEND' plot ofErdman, 1985). Ranges of values for basalt units2a to 2e are shown as 'unit2' in 1000 r"--- the shaded area.

10 -

L I Figure 5-16. MORB-normalized trace element plots of islandan' Fi gure 5-15. Chondrite-normalized minor element plot for and other typical suites ofthe shoshonitic associationafter Sloman hi]:h-potassium calcalkaline and shoshonitic lavas from southern (1989) compared to Quesnelarc basalts. Rangeand median values Ita dy compared to Quesnel basalts, after Ellamet al. (1989). for Quesnel basalts ofunits 2a to 2e are shown.

58 Geological Survey Branch Ministry of Employment and lnvesnnent

~ ~~~

shoshonites from the Gough Islands. A number ofsimilar mineralogically by the presenceof modal hc.rnble:nde, bivariant plots with various combinations of barium,chro- greater than average amounts of plagioclase are and charac- mium, zirconium, vanadium, yttrium and PzOs were used terized chemically by normative hypersthene and quartz. by MorIimerto produce the same subdivision theof Nicola The silica content io these rocks is close to saturatation and rocks as the niobium-barium ratio and BaPzOs diagrams typical norm compositions have around IO% olivine with shown on Figure 5-13. only a little quartz or nepheline. The oldest parts of the arc, The alkaline nature and shoshonitic association of represented by the transitional subalkaline (thcdeiitic:) to Quesnel basaltsare possibly best demonstrated by extended calcalkaline rocks of unit la. The silica-saturatedrock!; are rare earth diagrams, or ‘spidergrams’. These utilize mid- interspersed with undersaturatedrocks in the upper parts of ocean-ridge basalt (MORB) and mantle or chondrite-nor- unit 2 and ultimately are overlain by analcite-karing; ba- malized multi-element analyses as describedby Pearce salts. Possibly the volcanic belt representsa sequence from (1983) and discussed by Rock (1987).The alkalic rocks are tholeiitic-like basaltsthrough toalkalic basalts (units laand strongly enriched in the incompatibleor large-ion lithophile 2) and then a second sequence(units 3 and 4). repatin;: the elements (LILE) and slightlyelevated in the light rare-earth first but under more hydrous conditions. elements WE)compared to the high field-strength ele- The basaltic rocks are enriched in both potassium and ments (HFSE). The slope and pattern of the chondrite-nor- sodium butthe abundance ofsodium generally exceedsthat malized orbulk-earthnormalized diagram(the ‘BEND’ plot of potassium. Sodium-rich compositionsare indi1:ated min- ofErdman,1985,shownonFigure5-14)showstheexpected eralogically by the presence of modal analcite. Chemical alkalic pattern for the Quesnel arc basalts. It contrasts with compositions plotted on various major oxide variation dia- the classical concave-upward curve of the within-plate ba- grams and minor element discriminationplots c11:arly show salt (WPB) pattern for plateau basalt of unit ll and the the high-potassiumcalcalkaline to strongly alkaline, potas- reference curves for N-MORB andEMORB. sic character of the rocks in units 2, 3 and 4: the main A comparison of chemical compositions canbe made volcanic arc constituents. Exceptions are theoldest volcanic with subductionzone, mantle-source alkalic mafic magmas deposits of unit la; these rocks are primitive Hawaiian-type of southern Italy which have typical enrichment of LILE lavas transitional between tholeiite andcalcalkaline comp over REE with negative nobium anomalies (Ellam er al. sitions. Theyare interpreted to have originatedin a mar:ginal 1989), as portrayed on Figure 5-15. The Quesnel rocks on basin or back-arc setting at the onset of (early) continent- this diagram occupy positions intermediate between the margin rifting (Bloodgood, 1987). The analyse!: from this mafic members of lowto high-potassium calcalkalineEtna map unit showlarge a amount ofscatter on various chemical and Salina lavas and the lowto high-potassium calcalkaline plots. The rocks appearto have undergone some nagnesium to potassic (shoshonitic association) lava of Stromboli and metasomatism that is indicated by an abundance of magne- Volcano. sian chlorite. A comparison usingMOB-normalized extended ele- Classification of rocks in the upper part of the Quasnel ment plots provides similar diagrams as the chondrite-nor- arc as shoshonites or part of a shoshonitesuite is :kgeIy,but malized data. Data from typicalshoshonite suites from the not totally, compatible with the original definitions, and Absaroka Mountains, Fiji, Aeolian Islands, Papua New usage ofthe term ‘shoshonite association’byJoplin (1’968). Guinea and Italian Dolomites are all associated with de- Shoshonite terminologyis permissible under the expanded structive plate margins (Sloman, 1989) and are shown on and less restrictive, widely applied recent usagec.f Morrison Figure 5-16 alongside Quesnel data. The similarity in pat- (1980). Mutschler and Mooney (1993) and cthen. The terns and element concentrationsbetween the basalts from Quesnel volcanics complyin most aspects with these more the various shoshonitesuites shown andthe Quesnel basalts liberal classification requirements for the use of the term of unit 2 is striking. Quesnel rocks in units 3 and 4 display shoshonite. Themain differences betweenQuesnel arc similar patterns but there is insufficient data to adequately shoshonites and those from elsewhereare that tl~eQuesnel detail their element distributions. rocks have sodium in excessof potassium and are strongly undersaturated with respect to silica, rather thm clcse to DISCUSSION silica saturation. Our preference, at least for field usage,is to usedescrip- The magmatic rocks of the Mesozoic Quesnelvolcanic tive names and mineralogical modifiers,for example, anal- belt, at least the major elements ofthe volcanic arc, are an cite-bearing pyroxene basalt or pyroxene amphibole assemblage of predominantlyalkalic olivine basalt, alkalic trachyandesite, feldspar-phyric amphibole pyroxene basalt, basalt to trachyandesite and genetically related intrusions. and so forth. Simple petrochemical terminology would ap- The rocks are characterized by silica-undersaturated, ply the TAS classification based on major oxid,: analysis- nepheline and olivine normative mafic compositions; they basalt, trachybasalt, basalt trachyandesite, trachyandesite contain, on average, 3 to 14% normative olivine and up to with unusual compositional variants picrobasalcor ba,saltic almost 15% normative nepheline.The lower to lower-mid- andesite and tephrite, basanite andphonotephrite and dle part of Ihe stratigraphy is characterized by silica-satu- tephriphonolite. Use of the more restrictive and specific rated or nearly saturated rocks. Theyare recognized class or series terms ‘shoshonite. shoshoniie suite or

Bulletin 97 59 British Columbia shoshoniteassociation’wouldrequiretheutilizationofother and rocks of the Roman region and Sunda-Banda arc, as petrochemical data such as rare earth and other minor ele- reviewed by Nelson andBellefontaine (1996), where man- ment discrimination plots, studies or ferroudfemc ratios, tle-source alkaline lava results from a continental crust and so forth. Classificationof therocks as shoshonites draws contribution, similar to the shoshonites of the western attention to the petrologic affiliation of the Quesnel arc United States of America. rocks withsimilar alkaline rocks in destructiveplate bound- Shoshonites commonly postdate the cessation of sub- ary subduction zone settings elsewhere around the world, duction. One of the main settings is the late stages of arc notably the young volcanic island arcs of the southwest evolution near arc termini (Jakes and White, 1972). This Pacific. may be applicable for Mortimer’s unit 1 rocks in Nicola Alkali basalts of the shosonitic association inthe Ques- volcanics to the south where one ofthe three volcanic units ne1 belt are volcanic products of subduction-related island is shoshonitic,but not applicable to Quesnelwhere arc magmatism. These relativelyrare arc rocks in this con- shoshonites are present througout the entire volcanic suc- vergent plate margin setting, compared to commonly pre- cession. Similarly,arcreversalsor‘flippingover’ofsubduc- sent calcalkaline suites, are characterized by the abundance tion direction withalkalic rocks (and copper-gold deposits), of potassium, barium, strontium, rubidium and P2O5, and as discussed by Solomon (1990) and espoused by Spence the lack of enrichment in notably niobium, zirconium and (l985), arenot applicable to the Quesnel belt becausethere titanium as well as yttrium, ytterbium andother high field- is no mapping evidence for any changes in polarity of the strength elements. The magma generation in this type of arc with time. Arc rifting along deep-seated crustal-scale oceanic island arc setting is evidently a resultof melting of structures as in Fiji (Gill and Whelan, 1989), and possibly the asthenosphere in the deepest parts of the subductedslab along transforms, might be an applicable mechanism if above deep Wadati-Benioff subduction zones. Alkalic mag-modem examplesof lineaments and segmentation south- in matism is probably the result of combined petrogenetic west Pacific arcs are considered.This type of tectonicsetting processes including source enrichment fromthe subducted involving transform-related extension during transcurent slab, partial melting of a (? repeatedly) metasomatised, faults has been proposedfor the segmentation ofthe north- LILE-enriched, depleted mantle wedgeand fractional crys- ern Quesnel Taklaarc by Paterson (1977)to produce aseries tallization. This type of magma genesis for alkalic rocks of interconnectedvolcanic edifices with intervening basins. with nepheline normative, potassium and LILE-enriched A similar tectonic setting with regional strike-slip faulting basalts, including shoshonites, as slab melts of metasoma- and related Triassic alkalic magmatism is described in the tised mantle wedge-material is proposed by Bailey et 01. Dolomites of northem Italy bySloman (1989). but the (1989) for rocks in the Kurile arc that are similar to the volcanism is not equivalent to that in the Quesnel belt due Quesnel belt volcanics. The magma generation in the to the degree ofolder continental crust involvement. Kuriles, and in other arcs, takes place in a tectonic regime In the Quesnel belt the alkalic basalts of shoshonitic that permits upwelling ofenriched lithosphere, probablyin association occur throughoutthe stratigraphicsuccession of zones of localized rifting of ocean basin lithosphere that the volcanic arc. The presence alkalicof rocks ofshoshonite allows hybridized mantle uplift and decompression melting association is a widespread phenomenon throughout the to produce the distinctive alkalic magmas (Mclnnes and northern Nicola Groupvolcanics and is a product of long- Cameron, 1994). Comparable basic alkalic rocks in intra- livedvolcanism (Norian to Sinemurian andpossibly oceanic arcs with similar tectonic settingsoccur in Fiji,Lihir Pliensbachian). The magma generation, therefore cannot and the Marianas. In contrast, other alkalic arcs, have dif- simply be related to late or post-subduction, ‘arc-reversal’ ferent compositions with low K/Na ratios and enrichment events associated with some type of LILE-enriched litho- in niobium and zirconium; these arcs may represent intra- sphere upwelling during short-term extension (or transten- plate settings. sion). Thereis considerablesimilarity inthe tectonic setting Mixed sourceor process magmatism is evident and can with the active subduction-related alkalic submarine mag- be intermittent and repetitive; shoshonites are commonly matismina350-kilometresegmentofthenorthernMarianas interlayered with transitional (high-K to calcalkalic lavas). arc -a nascent shoshonite arc within alarger belt of low-po- This is evidence for complicated tectonic regimes and a tassium basaltic magmas (Stem et al., 1988). Possibly the great diversity of petrogenetic processes. Assimilation of Quesnel arc-building shoshonitic magmatism represents a sediment and continental lithosphere is a possibility in the similar, subduction-related compressive volcanismthat was generation of some alkaline magma but thisis not evident reinitiated after earlier continental-marginback-arc rifting in the Quesnel island arc environment where low initial producedenriched lithosphere alonga steeply dipping strontium isotope values indicate primitive magma sources length of the convergentplate margin. without siginificant crustal contribution (Beddoe-Stevens The shoshonitic volcanics of Quesnellia are a suite of and Lambert, 1981; Preto et al., 1979). Other mechanisms alkalic basic rocks relativelyrare worldwide, but they con- for alkalic magma generation are arc-continent collision,as stitute a significant part of a 500-kilometre long belt the in in the Papua New Guinea Highlands and Greece, again not eastern Intermontane region of the Cordillera. Analagous applicable in the case of the Quesnel arc. This contrast is alkalic rocks in island chains of roughly the same dimen- also evident for the Aeolian potassiclavas of southern Italy sions as the Quesnel belt occurin the Tabar-Lihir-Targa-Feni

60 Geoiogical Survey Branch Ministry of Employmenrrmd?nvesrmenf arc, Papua New Guinuea, andtheadjoiuing New Britain arc, volcanics (Logan and Koyanagi, 1994; Brown et aI., in as described by Mclnnis and Cameron (1994). The typical preparation). The relationship of these two similar arcs in silica-undersaturated rocks of high-potassium calcalkaline different terranes is discussed by Nelson and Mihalynuk magma series nepheline-normative magmatismare unusual (1993). Thealkalic arc volcanics are similar to ii number of for island arcs and are more characteristicof continentalrifts other primitive intra-oceanicisland arcs with alkalic basalt or intraplate hot spots. The Cordilleran alkalic arc rocks and andesite compositionsbut are chemically distinct from appear to be the products of a combination of complex still other shoshonitic arcs built on continental basementor tectonic events and magmatic processes, possibly indicatinginvolving continent-margininteractions during subduction. unusual chemical compositions the in mantle-wedge source In the Quesnel belt, as elswhere in shoshonilic terranes, region or subducting plate edge-effectsin a primitive oce- them is a persistent presence of economical1:y important anic arc setting. There are identical, time-equivalent rocks copper-gold and gold deposits (Muller and Groves, 1993; in the adjoining terrane, Stikinia, in the so-called Stuhini Mutschler and Mooney, 1993.

Bulletin 97 61 62 Geological Survey Branch Ministry of Employment adInvesimenr ” CHAPTER 6 STRUCTURE

REGIONAL DEFORMATIONAND Barkerville Terrane whichis not part of Quesnellia. Thefirst FOLDING four phasesproduced coaxial foldswith northwesterly trending axes and variably dippingaxial planes. ‘Thesefolds The structuresof the central Quesnel belt were initially are overprinted by northeasterly striking folds with vt:rtical produced during accretion of Quesnellia arc rocks and the axial planes. McMullin’s phase one structures are present underlying Crooked amphibolite with rocks of the North only in rocks of Barkerville Terrane and pxsibly the American continental prism. This event is interpreted by Crooked amphibolite, the basal oceanic rock!; on which Nixoneral.(1993)tohavetakenplacefrom186to180Ma, Quesnellia evolved. He considered thatthe oldest structures the Toarcian epoch. Subsequent tectonic activity resulted inin Quesnellia formed during the second phase of regional a number of overlapping and dominating phases of defor- deformation, producing tight to isoclinal folds with a well mation accompanied by a metamorphic culmination that developed axial planar fabric. The attitudes of these folds followed tectonic crustal thickening. Foldsare most evident are affected by later deformation, but generally fold axes in Quesnellia in both the thick sedimentary successionsof trend to the northwest. Rees (1987) suggested that these unit 1 and the thin sedimentary units interbedded with the folds have northeasterlyto easterly vergance. In Quesnellia basaltic volcanic rocks of unit 2. The volcanic rocks are and the Barkerville Terranethis second phase c’ffolding is extensively blockfaulted but the massive appearance of the synmetamorhphic in that metamorphic mineral growth is volcanic assemblages does notreadily allow thedefinition synchronous with,orslightly postdates, develoFmentof the of folds and the resolution of fold patterns within the axial planar foliation. volcanic units. The third phaseof regional deformation recognized by Numerous studies of structures andmetamorphism McMullin, D2 in Quesnellia, generated uprightto semi-re- have been conducted inthe high-grade metamorphic rocks cumhant, westward-verging ‘backfolds’that he considered of theBarkerville Terrane to the east of the Quesnel belt (see to he responsiblefor the majormapscale featuresin the area discussion of previous work, Chapter 1). The structural describedin this report. He states that fold axestrend relationships betweenQuesnel and Barkerville terranes northwesterly and that axialplanes generally dip steeply to have beendiscussed by Ross et al. (1985); Rees (1987) and the northeast. A second cleavageis a nonpene!mtive menu- Struik(1988a). among others, and summarized by lation that is indistinguishable from theolder cleavage. At McMullin (1990). Structures within Nicola rocks and the higher structural levels the rocks have either a crenulation structural development of Quesnellia have been the topics or spaced fracture cleavage. Some metamorplic mineral addressed by Carye (1985) and Bloodgood (1987c, 1990).growth is evident with this deformation but thf: events are Previous workers have identifiedfrom two to five generally postmetamorphic; metamorphic mineral isclgrads phases of folding and Elsby (1985) even suggested that were foldedduring this deformation. Late defonnation with normal faulting represents a sixth phase of regional defor- possibly two separate, possibly conjugate fold syste:ms, is mation. In the eastern part of the Quesnel Terrane, Rees described by McMullin. The late deformatio;l produced (1987) has describedfive deformational episodes which he relates to the development of the arc, its subsequent accre- A. FIRST PHASE (F1) 8. SECONC. PHASE (F2) tion with cratonic North America and to later tectonism 1 FOLD GEOMETRV FOLDOEOMEFRY involving perictatonic and cratonic rock of the Omineca belt as well as allocthonous Quesnellia. We have adopted Rees’ convention of describing the sequence of regional deformationalevents by the letter D, with Dl for the earliest to Ds for the latest event. In the specific areas of our study we use the term F, for example FI and Fz, to describe the relative sequence of events recognized. Thus the earliest I C. GEOMETRY RESULTING FROM F2 OVERPRlNllNG F1 period of deformation we recognize in the Quesnel belt is designated F1, followed hyFz but this sequence can come- spond to and begin with any of the regional events, most likely either D;! or l%. The complicated and notaltogether consistent scenario described by different investigatorshas beensummarized by McMullin (1990) and is outlined below. Figure 6-1.Schematic illustration of the geometric relationships McMullin considered that five phases of deformation between FI and R folding. Recumbant first phase structures are can be recognized in the Quesnel Lake area, mainly in the overprinted by doubly plunging second phase fold sets. remlting wellstratified metasedimentary successions of the in the developmentof relaying antiform-synformpairs.

Bulleiin 97 63 Brilish Columbia open small-scale buckles and warps.In one system upright detailed studies have been done.For example, during peri- axial planes of folds with poorly developedfracture cleav- ods of low water flow in the Quesnel River near Likely,a age trend northor northwest. The youngestfold axes trend flat-lying, sinous fault and 1-metre wide shear zone mark northeastward. The late deformation postdates peak meta- the contact between older hangingwall basaltic rocks ofunit morphism and someretrogression is evident. 2 and footwall sedimentary rocks of unit 5. Also at the QR Most investigators in the Quesnel Trough recognized deposit, 13 kilometres northwest of Likely,interpretation of two major, consecutive, and probably protracted phases of drill core by Fox et al. (1986) proposes that one or more deformation (Rees, 1987; Bloodgood, 1987a; and Bailey, reverse fault structures such as Wally's fault are present 1990). A schematic illustration of the relationshipsbetween They are cut by younger, steeply dipping normal faults. F1 and Fz is shown on Figure 6-1.A third postmetamorphic, Northeasterly and northwesterly-striking normalfaults late structural event is usually described or is implicit. The are rarely seen in outcrop butare interpreted from outcrop first deformation coincides with the tectonic emplacement distribution and patterns of map units and their aeromag- of Quesnel Terrane onto Barkerville Terrane. Kinematic netic expression. A case for early, east-side-down, normal indicators from high-strain mnes and mylonites suggest fault structures that trend alongthe axis of the volcanic belt northeastward or eastward sense of shear (Rees, 1987). The has been made by Bailey (1978). The faults outline the second deformation phase coupled Quesnellia and Bark- trends and formcontacts of many of thevolcanic units and erville terranes into large-scale, southwesterly vergingsub- appear to have controlled the distribution of eruptive cen- recumbent folds that are outlined by the Z-shaped terrane tres. Reactivation of these high-angle extensional faults boundary. Evidence for a late (third) phase of deformation postdates thrustingbut is no later than Cretaceousas granitic is taken to be open folds or warps with no axial planar rocks of this age do not appear to be cut by them. foliation. Structures related to the late events are subtle. A third set of faults is present as a number of major, Rees related northwest-trending warps to this event but strike-slip structures along the poorly exposed terrane McMullin describes late, north and northwest-trending boundary of the western Quesnel belt with Cache Creek structures and Bailey documents northeasterlytrending fold rocks. Namw belts of Middle Jurassic and youngerclastic axes. One area with good outcrop evidence for superim- deposits are preserved along thefault zones. These faults are posed fold axes with divergent trends is available on the part of the Pinchi andFraser fault systems; asubsidiary fault north bank of the Quesnel River near Likely. There thin-bed-system along the Quesnel River,its location only inferred, ded sedimentary rocks of unit 5 exhibit interference struc- is informally named the Quesnelfault. A fault in the north- tures resulting from the superimposition of northwesterly central part of the map area,the Chiaz fault (Bailey, 1988a). trending, moderately northwest-plunging, isoclinalfolds on forms an arcuate structure that extends to the north of the northeasterly trending open to tight folds with gently south- Quesnel fault. It is defined largely by aeromagnetic and west-plunging minorfold axes. induced polarization surveys. This fault has dextrally dis- placed Cretaceous granite by upto 4 kilometres and has a west-side-up throw of at least 5 kilometres. Extensional FAULTING faulting in the Quesnel central volcanic belt during the mid-Tertiary is possibly also related to the large-scalestrike- Faulting of three types and discrete pericds is evident: thrust faulting that coincides with accretion outlines the slip faulting. The structural extension has produceda major crustal structures and defines the terrane and major number of small, north to northwesterly trending grabens map unit boundaries; high-angle to listric normal faults that that are probably transtensional basins. They were sites of either follow the northwesterly trendof stratigraphic units Eocene sedimentation and volcanism. or are transverse to them andstrike easterly to northeasterly; and late strike-slip movements along the western terrane DETAILED STRUCTURAL STUDIESIN boundary and related extensional faulting within the asso- THE EUREKA PEAK AND SPANISH ciated transtensional basins. LAKE AREAS The major, early low-angle thrust fault in the map area is the Eureka thrust, a boundary fault between the Crooked Bloodgoodconductedanumberofstructurallyfocused, amphiboliteofQuesnelliaandtheunderlyingrocksofBark- detailed studies in the black phyllite succession of unit 1 in erville Terrane . This and similar structures in Barkerville two regions within the map area near Eureka Peak and rockstothenortharethePundataandPleasantValleythrusts Spanish Lake (Bloodgood, 1987a. 1988.1990). She recog- described by Struik (1983,1988b). Brown andRees (1981) nized overprinting relationships of structural elements that and Rees (1987) refer to the Eureka thrust as the Quesnel indicate two distinct deformationalepisodes produced folds Lake shear mne. Struik (1988a) also suggests, on the basis within the rocks of the Quesnel Terrane. Her conclusions of stratigraphic repetition,'that is evident from conodont (Bloodgood, 1990, pages 15-27)are summarized below. studies, that one, and probably more,thrusts are internally First phase folds (F1) are tight to isoclinal, eastwardly present in the Quesnel basal sedimentary unit. In the vol- verging structurescharacterized byapenetrativeslaty cleav- canic map units low-angle faulting is difficult to document age and mineral elongation lineation. In the Eureka Peak but evidencefor it is available in a number of places where area, a structural transition is observed, characterized by

64 Geological Survey Branch Ministv of Employment and Inve:ifmenf

cleavage surface. The material remoblilized tly pressure solution processes maybe present as the small quartz veins within hingesof folds andas quartz veinlets that are parallel and subparallelto bedding. In the Eureka Peak area, fvst phase slaty cleavage shows a consistent variation in orientation from the limbto the hinge regions of the Eureka Peak syncline:. At ]lower structural levels and on the limbof the syncline,:?I folds are tight to isoclinal. The axial plane cleavage i!; genrly to moderately inclined to the northwest.In contrast, at higher structural levels within the volcanic succession.. andi.n the I I hinge regions of the syncline, SI is more steeply inclined Figure 6-2. Schematic srmctural cross-sections-A. Spanish Lake and foldsare open and upright.The change in orientationof and. B. Eureka Peak areas: locations indicated on Figure- 2-3. Man the cleavage, andthe transition in fold style is a consequence units Bloodgood (IsSOj in brackets. of of greater flattening strains along the limb of the syncline and the distance away from the volcanic-sediinentary li- tight to isoclinal folding at lower shuctural levels, gradually thologic contact. The deformation is most intmse in the becoming moreopen and uprightat higher structurallevels. regional-scale FI structures wererecognized in the phyllites which have accomodateda greater propofion of No the strain than the more competent volcanics.All FI folds Eureka Peak This contrasts with the Spanish Lakearea area. are easterly verging, outcrop-scale structures ,with maxi- where vergence ofF1 structuresindicates FI nappe to the an mumobservedlimblengthsofabout10metres;noregional- north of Spanish Lake (Figure62). A nonpenetrativespaced cleavageis developed parallel scale structures are recognized. The structures all shw the The slaty cleavage is to the axial plane of second phase(F2) folds. The F2 folds effects of subsequent deformation. deformed and cut by a spaced or crenulation cleavage (S2) are manifest as doubly plunging, open and upright buckle folds which deform FI and fold the tectonic boundaryinto and mineral lineations are commonly bentarounc:theEz fold the form of the Eureka Peak syncline.In the Spanish Lake hinges. area, F2 folds commonly havea box-fold geometry andthe In the Spanish Lake area, fine colour lamiuations and axial planar cleavage is developedin a conjugate thin greyto white siliceoussiltstone interbeds cle:rly outline orientation. bedding folds. Thereis also a widespread, well developed, penetrative slaty cleavage and bedding-cleavage intersec- PHASE I STRUCTURES tion lineation. FI folds, bothas mesoscopic and nlicroscopic scale structures, are tight to overturned with genllyto :mod- Phase one structures are penetrative slaty cleavage a eratelyinclined SI planes.Vergence of FI StructuIes is (SI), the lineation defined by the intersection of bedding on believed to be eastward but the structures :argely ob- the slaty cleavage (LI) and a mineral lineation. Theslaty to are scured by F2 overprinting. The sense ofsyrnmetry on phyllitic cleavage occurs closely spaced planes that de- as mesoscopic folds indicates the presence of a macroscopic fine a penetrative fabric. It is marked by a fine micaceous FI antifon. As no closure is seen, the area may lie on the or graphitic parting in the metasediments and a chloritic upper limb of largea FI nappe structure (Figure 6-2). parting in the volcanic rocks. The cleavage is axial planar to mesoscopic and microscopic folds, strikes north- both PHASE 2 STRUCTURES westerly, and dips variably to the northeast and southwest. A planar parting defines the cleavage in the moresiliceous Phase two deformation@2 in Quesnellia, the regional or slaty sediments and a more closely spaced, anastamosingD3 of McMullin, 1990) established the regional map pat- micaceous to graphitic foliation occurs in thefiner grained tern. Structuresassociated with this deformationare a non- sediments. The penetrative cleavage is most strongly devel- penetrative,spaced or crenulationcleavage and oped in argillaceous sediments and is poorly developed or bedding-cleavage or cleavage intersection line,ntions. All absent in coarser grained rocks, notably the overlying meta- earlier structures, including the Eureka thrust, w'e refolded volcanic suite. but the distinction between the two phases is difficult to Intersection lineations defined by the intersection of recognize unless unequivocaloverprinting relationships of bedding with oneof the cleavage planes, and mineral elon- the essentially coaxialstructures are evident. Thc structural gation intersections, plunge northwestor southeast at shal- elements associated withF2 are nearly coplanarandcolinear low to moderate angles, parallel to mesoscopic fold axes. with those of FI. As a result, the development of F2 Mineral elongationlineations are defined primarily by elon- mesoscopic folds is not always obvious. Evidence in out- gate quartz grains and quartz rods. crop at lower structurallevels is the overprint tightening of A darkcoloration along cleavage planesoutlines cleav- FI folds with an increasedratio of amplitudeto wavelength. age stripes. In thm section this striping appears to be due to As a result of similar orientation, the F1 structu~~susually the concentration of insoluble material along the cleavage appear only slightly modified by Fz although ri?foldi:ngis planes, suggestive of extensive dissolution along the evident locally. Photo 6-1. Second phaseoverprint of first phase iswlinal fold. A penetrative slaty cleavage (Si) is well developed axial planarto the first phase structure, whichis overprinted by a spaced second cleavage(Sz). Local refoldingby Fz has occurredalong the limb of FI.

Photo 6-2. Imbrication along the contact betweenthe Crooked amphibolite and the Triassic black phyllites. An imbricate slice of the Triassic metasedimentslies in the hangingwall ofthe fault. Quartz veins are prominent close to the fault zone, which is overprinted by southwesterly dippingFz crenulations.

66 Geological Survey Branch Minislry of Employment and Inveslmenl

Photo 6-3. Second phase foldingof the gently inclined bedding has a conjugate kink-type geometry.The quartz veinin the upper rixht is parallel to both bedding and the slaty cleavage(So and SI,respectively).

Photo 6-4. Pian view of a slaty cleavage surface(SI) deformed by Fz. Overprinting of the Fz fold geometry gives riseto the relaying antiformal culminations and synformal depressions.LIis deformed about theFz fold axis, which is parallel to thepen. The development of this fealure is schematically illustratedin Figure 6-1.

Bulletin 97 67 ~ ~~~~~~

The Sz spaced cleavage strikes northwest and dips FRACTURES AND QUARTZ VEINS moderately to steeply to the northeast and southwest. This is a nonpenetrativecleavage within both the metasediments Fractures, many filled with quartz, are common fea- and the metavolcanic rocks. Cleavage spacing varies with tures at all scales in the EurekaPeak and SpanishLake areas. lithology and positionon mesoscopic structures. The more Some quartz veins are deformed andothers are not. indicating that fracturing occurred throughout the deformational closely spaced individual cleavage planes vary from1 to 15 history. It is likely that veins formed as pan of a continuum millimetres apart. Cleavagein the Nicola volcanic rocks is during the evolution in structural development. The quartz weakly deveIoped and, where present, is best developed veins most commonly vary from1 to 20 millimetresin width near the hinges offolds rather than onthe limbs. Throughout and tens of centimetres in length but can be up to a metre the volcanic members, the cleavage dips steeply to the wide and several metres long. Small, early quartz veins northeast or southwest. It is defined by a chloritic parting outlinerootless isoclinal folds, the limbs of which have been and the spacing varies from 1 to 3 millimetres in the fine- removed, probablyas a result of pressure solution along the grained tuffs to 3 to 4 centimetres in the coarser grained cleavage surfaces. Extensional, quartz-filled fractures and rocks. dilations oriented at low angles to bedding andcleavage, as IntheSpanishLakearea,secondphasedefomation@z) well as sygmoidal fractures perpendicular to fold axes, occur predominantly inthe metasedimentary successions. refolds earlier structures, bedding and slaty cleavage (SI). The quartz in narrow veinlets typically occurs as elon- Fz folds are open and upright andare accompanied by an gate to fibrous grains, commonly perpendicular to vein axial planar nonpenetrative spaced cleavage. The foldsare walls. The larger veins are characterized by more equant, generally southwesterly verging, trend northwest (280" to blockier quartz c~~stais.Textures characteristic of repeated 310"). and dip moderately to steeply to the northeast or, crack-sealvein growth have been recognized thefrom study gently to moderately southwest. Local small-scale crenula- of vein material (Bloodgood, 1987a). Figure6-3 illustrates tions of SI are associated with Fz deformation. Well dis- the various vein geometries in relation to cleavage and played Fz structures locally have a characterisiticbox-fold bedding orientationsand Photos6-5 to 6-7 show the various geometry. Therethe Sz cleavage forms conjugatesets, axial vein styles. Fractures initially formed parallel to the direc- planar to the fold structures, and this cleavage commonly tion of maximum compressive stress,at low angles to bed- defines kink-band boundaries. Linearstructures associated ding, and a high angle to cleavage. During progressive with Fz deformation are SdSz or S162 intersection linea- deformation, both bedding andthe early formed veins were tions. These stmctures are doubly plunging, inclined tothe folded and disrupted. northwest and southeast. Undeformed, spaced fractures are developed in all lithologies throughout the region. Spacing offractures varies Second phasestructures in the Spanish Lake area estab- from 1 to 100 centimetres and varies in rocks of different lish the geometry ofthe tectonic boundary and map pattern. competency. Open joints have been recognized throughout To the north the FIEZinterference structures determine the the study area. They are oriented perpendicular to the fold outcrop pattern of the Crooked amphibolite. The steeply axis and axial plane ofthe mesoscopic folds and dip steeply dipping Fz axial plane and doubly plunging fold axis im- to the north and south. posed upon a gently dippingF1 axial surface results inthe development of a series of antiformal culminations and synformal depressions along the trend of the fold axis.The deepest structural levels are thusexposed where an Fz antiform overprints an F1 antiform. This relationship is evident in the map area where Crooked amphibolite is exposed along the coincident antiformal axis. To the north of this axial trace higher structural levels are preserved within lobate synformal depressions and the higher stratigraphic members of unit 1 are exposed (Bloodgood's unit Tra6).Various structural elementsand relationships between Fland Fz are illustrated on Photos 6-1 to 6-4. Locally, north of Spanish Lake, in hinge regions of the F1 folds, the Sz cleavage is rotated away from its typical Figure 6-3. Common vein geometries. Earliest veins developed orientation, into parallelism or near parallelism with the F1 parallel to bedding and perpendicular to the developing cleavage. axial surface. This consistent relationship in the area sug- Pressure solutionfeatures associated with SI and S2 cleavage suggest fluid took place throughout deformation and resulted gests the presence of an F1 antiform overprinted by an Fz flow in both deformedand undeformed veins. Goldoccurs in the earlier antiform. Elsewhere the Sz surface is inclined at a shallow veins particularly near fold hinges and is associated with small angle to the southwest, subparallel to SI. amounts of pyrite, chalcopyrite and pyrrhotite.

68 Geological SUN^ Branch Ministry of Employment and Investment

I. Photo 6-5. Stongly deformedquartz veins within black phyllites. upright F2 fold. In some areas remobilization 01' vein4lling These isoclinally folded veins are plunging at a shallow angle material by pressure solution is suggested by the lruncation of toward the topof the photo, and are overprinted by F2. some veins against the cleavage surface.

Plate 6-7. Early formed, foldedquartz veins truncated bya later, blocky vein.

" Bulletin 97 69 British Columbia

EOCENE EXTENSIONAND GRABEN (NTS 92P), the Eocene rocks are fairly abundant as rela- DEVELOPMENT tively thin Tertiaryunits under a more widespread cover of Miocene basalt flows. Locally thick units of Eocenerocks The Tertiary sedimentary andash-flow deposits in the are present in faulted depressions. There the rocks are re- project area (unit IO) are largely confined to a belt 3 to 6 ferred to as the Kamloops Group but the Tertiary assem- kilometres wide by40 kilometres-long in the south-central blages also include Eocene and younger, units termed the part of the area studied (Figure 3-8). The poorly exposed Skull Hill and Deadman River Formations (Campbell and Eocene rocks are preserved in anarrow, fault-bounded Tipper, 1971). depression, possibly a graben, that is now occupied over The Eocene volcanic sequence in the Quesnel belt, much of its length bythe Horsefly River. Thebelt of Eocene sedimentary and ash-flow deposits is centred on Horsefly consisting of oldest biotite-bearing trachybasalt flows, the from where if can be followed northwesterly to Hazeltine thickest part of the sedimentary succession the and younger, and Edneycreeks near Quesnel Lake and east-southeasterly overlying ash flows, is preserved in its entirety only in the into the headwaters of the Horsefly River. The Eocene postulated graben structure. The original structural depres- ash-flows are part of a once extensive Tertiary cover that sion is nowlargely exhumed and has been infilled by unconformably overlies Quesnel belt volcanic rocks and glaciogenic and fluvial deposits and is covered by thick parts of the quartz diorite pluton south of Horsefly, the alluvium. Along, or near, the structural margins of the gra- Takomkane batholith. To the north of the Quesnel River, ben there are locally vuggy,quartz-calcite veins that suggest abut 25 kilometres southeast of Quesnel, there are two there has been Tertiary hydrothermal activity. The veins outliers of these Tertiary rocks overlying sedimentary rocks contain elements suchas arsenic, mercury, barium andsilver of unit 1. South of Horsefly around the Takomkane (Appendix M) and havethe appearance of low-temperature batholith, and evenfurther south inthe Bonaparte Lakearea open-space filling, typical of epithermal mineralization.

70 Geological Survey Branch Ministry of Empioyment am!Investmem "

CHAPTER 7 METAMORPHISM

Metamorphic gradeof the rocks of the central Quesnel Work', Chapter 1). Theirconclusions havebeen synthesized belt is, for the most part, subgreenschist facies. Readef al., by Greenwood ef al. (1991) and summarized by Campbell (1991) assigns the rocks of the study area to mainly the (1978) and Read,et al. (1991) on maps showing metamor- prehnjtepumpellyite zone. Prehnjte has been infrequently phic isograds in abasic Barrovian sequence (Figure 7-.l).A noted (Schink, 1974; Morton, 1986) but the volcanic rockssyntectonic to post-tectonic, early-Middle to Late Jurassic are characterized by the widespread occurrence of zeolite regional metamorphic event is a generalizatiori suggested mineral assemblages,typical of burial metamorphic condi- by most investigators. McMuIlin (1990)concluJies that the tions. Sedimentary rocks of unit 1, however, are metamor- metamorphic history canbe subdivided into h:sequential phosed to greenschist facies in the easternmost part of the even& all related to specific periods of deformatio:n. He map area. The higher grade in the eastern partof the belt is summarizes (McMullin, 1990, page 198) that: attributed to crustal thickening caused by thrustingof Ques- Metamorphic mica growth was confinedto the fnst nellia over the Omineca Belt andto subsequent deformation phase of deformation @I) but garnet mayhave at the BarkerviUe-Quesnellia contact. Regional metamor- grown late in Dl; phism of amphibolite facies in the rocks of Barkerville Terrane indicates the sharp transitionin metamorphic grade * The major mineral growth occurredduring D2 defor- across the terrane boundary. mation (our FI). The Dz foliation wraps around the Studies of regional metamorphism in the Quesnel Lake gametporphyroblasts butlaterkyanitear~dsLaorolite region havebeen conducted by many workers(see 'Previous porphyroblasts overgrowit,

Figure 7-1. Metamorphic faciesand zones, central Quesnel Trough (Quesnel Terrane)and adjoining Cache Creek Terrane and Bakerville Subterrane, modified from Readet al. (1991) and Greenwood et al. (1991). Heavy lines represent terrane boundaries. Symbolsused: subgreenschist: z - zeolite, p - prehnite-pumpellyite; greenschist:e - chlorite, b -biotite, g - almandine gameq amphibolite:stk - kyanite f staurolite, s - siliimanite. Small square with number refers to conodont colour alteration index(CAI).

Bulletin 97 71 Metamorphism wanedduring late deformation @3), porphyroblasts and as fine stringers parallel to SI.hger our Fz, and metamorphic recrystallization ceased magnetite porphyroblasts appear to truncateSI schistosity, except in high-grade cores of anticlines; locally but smaller grains are commonly oriented parallel to the there is metamorphic retrogression. main foliation. MicrotexNres suggest that metamorphism was syn- METAMORPHISM OF THE CENTRAL chronous with deformation resulting inthe development of the primary schistosity. The poikilitic hornblende and epi- QUESNEL BELT dote enclose a metamorphic foliation and are, therefore, Studies of metamorphicrocks at the eastern boundary syntectonic to post-tectonic. Growthof biotite during a later of Quesnellia,along its tectonic contact with rock of Bark- phase of deformation is indicated by the growth of biotite erville Terrane, were conducted by Bloodgood (1987a.b.c. across the foliation andparallel to the axial plane of micrc- 1990) in the Eureka Peak area. Her observations scopic kinks. Chlorite is pervasive anddefines the schistose (Bloodgood, 1987b) are the basis of much of the following foliation. discussion. Metamorphic grades cut across the tectonic boundary PHYLLITES at a low angle and conformto the regional structures related Phyllites with a characteristicpenetrative foliation (SI), to the emplacement and deformationof theQuesnel Terrane. defined by the planar alignment of muscovite, paragonite Metamorphic mineral assemblages are characteristic of the and minor chlorite, also contain porphyroblasts of gamet, greenschist facies, and vary from chlorite to garnet grade. albite,chloritoid and ilmenite. All porphyroblasts are Metamorphic effects are most evident adjacent to the tec- poikilitic, containing inclusions ofquartz and opaquemin- tonic boundary, and particularly withinthe basal partof the erals. Pressure shadows of quartz and chlorite occur in metasedimentary succession where rocks of garnet grade association with all porphyroblast phases. Compositional are exposed. Metamorphic grade decreases rapidly away layering is defined by quartz-rich versus chlorite-richbands. from the boundary, both stratigraphically and structurally Quartz-filled fractures (veins) occur commonly throughout upsection. Volcanic rocks of chlorite grade are prevalent in the rocks, mainly oriented parallel or subparalleltobedding. the core region of the Eureka Peak syncline. The veins are variably deformed and the quartz is highly strained. The quartz-filledveins and fractures probably METAMORPHIC ASSEMBLAGES formed by pressure-solution processes as fluids generated - during dehydration reactions passedthrough the rocks. FACIES AND ZONES There is a marked increase in the intensity of hydraulic fracturing at higher structural and stratigraphic levels, indi- CROOKED AMPHIBOLITE cated by the increased development of pressure-solution Crooked ampbibolite occurs as fine-grained chlorite- cleavage and the absence of ilmenite porphyroblasts. feldspar-amphibolite schist and a coarsegrained actinolite Porphyroblast phases include garnet varying from schist. Metamorphic mineral assemblages contain horn- small corroded grains to large, euhedral crystals that range blende, actinolite, chlorite, biotite, talc, quartz and calcite. in size from 0.5 to 4 millimetres. Althoughthere is consid- In the chlorite-feldspar-amphibole rock, a strongly devel- erable variation in compositionand zoning within individ- oped schistose foliation (Si), defined by planar alignment ual grains, compositions approximate those of almandine. of chlorite and lesser biotite flakes. is parallel to the compo- The gamet porphyroblasts generally contain quartz or il- sitional layering.Chlorite oriented parallel tothe schistose menite inclusions, but sometimes are completely free of foliation also occurs as intergrowths withfine-grained them. McMullin (1990) notes that the weakly poikilitic to quartz. Growth chloriteof and biotite was synchronous with inclusion-free nature of the garnets from Quesnellia rocks first phase deformation but there is evidence for some can be used to distinguish them from the inclusion-rich continued mineralgrowth during later deformation. garnets from rocks of higher metamorphic grade. Albite Porphyroblasts of green, pleochroic hornblende are grains vary in size from 0.5 to 2.5 millimetres although some aligned parallel to the schistosity. They contain inclusion as large as 7.5 millimetres have been noted.Inclusion trains trains of ilmenite, quartz and plagioclase and partially to of quartz in the porphyroblasts sometimescomprise up to entirely enclose biotite flakes parallel to the SI foliation. 50 per cent of the grain.Albite commonlyshows an angular Embayed, inclusion-riddled porphyroblasts of epidoteoc- discordance of up to20" between the external foliation and cur randomly throughoutthe rocks. They varyin size from the foliation withinthe porphyroblasts, but curved inclusion small to moderately sizedgrains and are occasionally envel- trains (helicitic textures) are not recorded. Ilmenite forms oped by actinolite porphyroblasts. Ilmenite forms blebs, small porphyroblaststhat are oriented parallel to the main small blades andscaly masses parallel to the foliation and foliation and often contains quartz inclusions. Quartz and asinclusion trains within porphyroblasts. Rare helicitic chlorite strain shadows oriented at low angles to the cleav- textures in hornblende indicate that some rotation of por- age plane are associated with the ilmenite. phyroblasts withinthe plane of foliation must have occurred Chloritoid porphyroblasts,as tabular grains commonly during growth.Magnetite occnrs both as coded,anhedral 1to 3 millimetres in length, growa variety in of orientations.

72 GeologicalSurvey Branch The grains occur withinpressure shadows of albite porphy- vesicles. Euhedralcrystals of zoisite between 0.C1 and 0.05 roblasts, parallel or at high angles to the main schistosity, millimetre in size occur in the groundmass aut1 very fine parallel to Szcrenulationsor at randomorientation unrelated grained epidote is an alterationof plagioclase in rkssociation to any ofthe prominent foliations. Chloritoidvaries in shape with calcite andsericite (saussurite). from idiomorphicto strongly poikilitic porphymblasts con- In the main volcanic arc assemblages of uni ts 2,:)and taining the SIfoliation. Inclusion trains within the porphy- 4 the rocks are of subgreenschist facies and, inplaces, roblasts show no evidenceof rotation during growth.On the virtually unaltered in appearance. The dark green to dark noahlimboftheEurekaPeaksyncline,thechloritoidoccurs grey pyroxene basalts contain hard, glassy malic crystals as coarse tabular porphyroblasts, showing no preferred ori- with only slightly chloritized rims, althoughthe plagioclase entation, and as intergrown, radiating masses. is universally turbid and saussuritized.Zeolite minerals are Metamorphic grade appears to decrease stratigmphi- widespread. The most abundant zeolite, laumonlite,is gen- cally upsection within the phyllites, and away from the erally found in veinlets andas coatings on fractures. If. also tectonic boundary. Similarly, the size of porphyroblast occurs togetherwith calcite as amatrix constitue:nt of phases within the phyllites also decreases progressively. sheared and brecciated rocksand volcanic breccias. Garnet, for example, forms very small grains riddled with Amygdules in vesicular flows containthomsonite and rare quartz before it disappears. At higher elevations, generally analcite together with calcite and lesser quanz. Filxous above 1900 metres, porphyroblastsare altogether absent in scolecitewas noted in a few vesiclesthe in subaerial hisalts the rocks although they retain a strongly developed foliationof unit 4. The presence of heulandite and chabazite in outlined by muscovite and paragonite. addition to analcite was noted by Bailey (19711). Locally zones of more intense replacementof the greenschist assem- NICOU GROUPMETAVOLCANICS blage are interpreted to be products of propylitic alteration related to nearby intrusive activity. Overall the appearance Metavolcanic rocks in the Eureka Peakarea equivalent to the Nicola Group, part of our unit la, lie within the of the main volcanicarc rocks is consistent with conditions albite-actinolite-chlorite zoneas defined by Winkler (1979). of regional burial metamorphism and very l0c:alized hy- The characteristic metamorphic minerals are actinolite, drothermal activity. chlorite, biotite and epidote. Timing of growth of metamor- Prehnite is rarely observed in the rocks, pumpellyile has phic minerals within the volcanics is difficult to constrain not been documented. Schink(1974)recognizedprehn,itein due to the general lack of deformation features, but is association with actinolite as an alteration of pyroxen,: and believed to be synchronous with that of the underlying in stringerscutting microperthite veinlets in moluonite and metasediments. The biotite isograd seems to traverse the syeniteattheShikoLakeintrusiun.Morton(l976)describes contact betweenthe two units. Where the rocksare foliated, prehnite together with an assemblage of epidote, chlorite, it is generally a tectonic foliation defined by growth of albite, magnetite and hematiteas the matrix oflapilli brec- chlorite. Actinolite needles within the groundmass show a cias in the Lemon Lake area. Healso notes that prehrlite is preferred alignment parallel to SI. In a few samples, the found with carbonate and chloritein fault zones in volcaui- tectonic foliationis parallel to a weakly developed primary clastic rocks near Quesnel Lake. trachytic flow foliation. Biotite is a minor replacement of mafic minerals but is not sufficiently abundant to define a CONDITIONS OF METAMORPHISM foliation. Actinoliteoccurs as rhombic porphyroblasts andas fine Mineral assemblages inthebasal metasedimentary part acicular needles in the groundmass and fractures within of Quesnellia are characteristic of greenschist facies. The phenocrysts. It replaces pyroxeneand hornblende phe- metamorphic isograd representing the first appmnce of nocrysts along cleavage planes,as overgrowths on rims of garnet closely followsthe terrane boundary, and locally lies grains and as fibrous tails parallel to cleavage traces. Albite, within Quesnellia, in the southeastern part th~: of map area. commonly together with calcite, is present in fractures.and Rocks of higher metamorphic grade, including staurolite, as fibrous growths withradial symmetry in vesicles. Biotite, kyanite and sillimanite-bearing rocks, occurimnlediat<:lyto usually in association withactinolite orchlorite, replacesthe the east in the Barkerville Terrane. The main volcanic arc mafic minerals. It occurs as stubby, tabular crystals and assemblages of the central Quesnel beltare zeolite-bearing, shows no preferred orientation. Chlorite is usually associ- locally propylitic rocks of subgreenschistfacies. ated with actinolite and epidote and is predominant where The Crooked amphibolite contains metamorphic horn- biotite is absent. It occurs most commonly as fine fibres blende, evidence that it experienced higher t8:mpeIature along cleavagetraces with actinoliteorbiotite in hornblende conditions within the overall low-grade metamorphic zone and with calcite in pyroxene. chloriteThe also forms as dull in which it occurs. Hornblende porphyroblastscontain op green-pleochroic fibres in the groundmass,outlining meta- ticallycontinuousinclusionsofepidote,biotiteandchlorite, morphic foliation. Both kinking of chlorite and growth of indicating that the hornblende developed slightly latex.The some chlorite synchronous to kinking is evident. Epidote change from actinoliteto hornblende is postulated to take and clinozoisite occur throughout the metavolcanic se place in the Eureka Peak area under pressure-tmperature quence as 0.1 to 0.5-millimetre grains in fractures and conditions similar to those in the adjoining phyllites,?based

Bulletin 97 73 on the appearance of almandine garnet, which occurs at primary igneous minerals. Chlorite outlines the planar fo- about 500" C in metapelitic rocks (Winkler, 1979). liation fabric. Saussuritization of plagioclase varies from The metapelitic black phyllite sequence is charac- slight to complete replacement by fine-grained epidote, terized by porphyroblasts of almandine garnet, chlorite, calcite and sericite. albite, chloritoid, muscoviteand quartz. The bulk composi- Thegrowth ofmetamorphic minerals asporphyroblasts tion of the rocks significantly affects the mineral paragene- occurred during and outlasted the phase one deformation sis. The presence ofchloritoid especially requires a special pi) that is associated withEarly Jurassic convergence and bulk composition characterizedby a high irodmagnesium terrane accretion. The first phase foliation is defmed in ratio, a relatively high aluminum content, and low potas- Crooked amphiboliteby growth of metamorphic biotite and sium, sodium andcalcium (Zen and Thompson,1974). The chlorite; in the metasedimentary phyllitic rocks by musco- presence of almandine-ricbgarnet indicates the higher tem- vite and phengite or paragonite; and in the older Nicola perature zone of greenschist facies metamorphism. The volcanics by chlorite. Most porpbymblasts contain inclu- proximity of these assemblages to the upper boundary theof sions following the SIfoliation which traversethe porphy- greenschist facies and limitedstability of chloritoid together roblasts as straight lines, and rarely show any curvature with albite in a limited temperaturerange of 510 to 575T within the porphyroblast. From this widespread textural accordingtoHoschek(1%9),accountsfortherelativerarity relationship it isinferred thatthe porphyroblasts developed of the observed assemblage.A minimum temperaturein the at the same time or after Dl deformation. order of 345°C can be inferred for chloritoid and chlorite- The prominence of fractures on all scales filled with bearingrocks based on studies of similarrocks in theBlack- crystalline quartz throughout the metamorphosed is water Range of the Rocky Mountains by Ghent et a!., rocks indicative of the presence of high-pressure fluid or fluids (1989). The colour alteration index (CAI) of conodonts ranges from CAI5 in the phyllites to 2 or 3 in the overlying (Cox er al., 1987). Mobilepore fluids were probably gener- volcanic rocks. This indicates chlorite zone metamorphic ated by dewatering reactions accompanying prograde meta- facies in the phyllites and prehnite-pnmpellyite to zeolite morphism.Pore-fluid pressures during regional metamorphic facies in the overlying Nicola volcanic assem- metamorphism tend to lower the effective stresses and, halges. These conditions correspond to subgreenschist together with dissolution processes of pressure solution, metamorphicconditions with maximum temperatures increase porosity and permeability (Etheridge et al., 1983, slightly in excess of 400" C (Greenwood et al., 1991). 1984; Coxetal., 1991). The large-scalecirculationoffluids Metamorphic assemblages in Nicola volcanics within probably dissipated heat from the underlying rocks. This or near the top of the basal sedimentary unit, mainly unit la, may account for the rapid decrease, without a break, in contain actinolite, epidote, chlorite, albite, biotite, quartz metamorphic grade observed across the tectonic terrane and calcite.The metamorphic minerals commonly occuras boundary and the abundance of veins and fractures in the overgrowths and replacementsalong cleavage planes inthe overlying rocks of Quesnellia.

74 Geological Survey Branch Minisrry of Employment and Inveshnenr CHAPTER 8 ECONOMIC GEOLOGY

The Quesnel Trough is a well-mineralized region typi- related propylitic gold deposits, are currently tht: most ad- cal of other Late Triassic - Early Jurassic volcano-plutonic vanced mine developments and main exploration targets in island arcs in the Cordillera. It hosts a wide variety of the region. The largest known deposit in the map area is mineral deposits. The area mapped contains 82 mineral Mount Polley, previously known as the Cariba>Bell de- occurrences recorded up to 1989 in the MINFILE property posit.Copper showings there wereknown for decades, file system; a few additional deposits of significance have probably from the time of the placer gold rush, but the been added inthis report (Table 8-1). Fifty-six of the occur- potential fora porphyry deposit wasfirstrecognized in :I964 rences are bedrock-hosted base and precious metal deposits;(Hodgsou er 01.. 1976). The style of mineralbation and twenty-one are placer gold deposits. The remaining five geological setting of Mount Polley are similar to other occurrences are sites with various other commodities, in- alkalic porphyry deposits in Quesnellia,notatrly Mount cluding industrial minerals, or unclassified deposit types. Milligan(Sketchley et ol., 1995). Similar depositsalso The major deposit types and individual occurrences of mostoccur to the north inthe Hogem batholith andae found to importance are summarized and discussed below. Most of the south at Afton mine and its nearby deposits in the Iron the mineral deposits in the map area not described in this Mask batholith and at Similco mine (Copper Mountain, report are summarized in the MINFILE records. Regional Ingerbelle, and others) in the Copper Mountain intrusions. geochemical survey results are summarized and lithogec- All these alkalic porphyry copper-gold deposits are de- chemical samples (assays) from altered zones and other scribed in Canadian Institute of Mining Metallurgy and geochemical indications of mineral occurrences are re- Petroleum - Special Volumes, (Sutherland Brown, 1!>76); ported in Table 8-4 and Appendix M, respectively, and and Special Volume 46 ‘Porphyry Depositsof tht Northern results are discussed nearthe end of this chapter. Cordillera’, (T.G.Schroeter, Editor, 1995). The principal recent exploration and economic devel- The regional distribution of intrusion-relattd deposits opment targets inthe central Quesnel beltare alkalic intru- in the Quesnel Trough follows, large in part, the central axis sion-relatedporphyry copper-gold deposits and of the volcanic belt. Plutons intrude along the axis c4 the gold-bearing propylitic alteration zones formed in volcanic volcanic arc; less commonly theyare emplaced in rocks of rocks peripheral to some of the intrusions. Other important the basal metasedimentary unit. Fromthe north, near (lues- targets are auriferous quartz veins in the black phyllite nel, to the southeast, near Horsefly,at intervals ,of approxi- metasedimentary succession. These rocks host auriferous mately 8 to 11 kilometres,the main prospects include: quartz veins of two similar-looking but possibly geneticallyMouse Mountain, Cantin Creek, Gerimi Creek, Maudlake, and temporally distinct types. The veins in some black QR, Bullion Lode, Mount Polley, ShikoLake, Kwun Lake phyllite members have potential to be mined as large ton- and Lemon Lake (Figure 8-1). The ‘best lookhg’ plutons nage, low-grade deposits. Tertiary rocks are mineralized formineralization. thatis, those with evidenceof hydrothex- with copper andgold in association with tourmaline- mal alteration, appear, on thebasis of their geological set- sericite-pyrite and propylitic alteration. Antimony-arsenic tings, to be the highest level, subvolcanic plulons. These and mercury mineralization in some apparently low-tem- were inevitably emplaced inthe upper units of he volcanic perature quartz-calcite veins indicates the potentialfor dis- arc. They are commonly recognized as differentiated dio- covery of epithemal deposits. Placer mining for gold, said rite-monzonite-syenite zoned or multiple intrusions or as to locally occur together with platinum, has been of major cupolas with irregularly shaped apophyses,dikes and sills. historical and economic importanceto the region.It contin- Brecciabodies are common, as bothintrusion and hy- ues to have importance becauseof a small amount of con- drothermal breccias. Elsewhere, and most conurlonly, many tinuing gold production in the district and exploration for of the mapped dioritic plutons andsmall plugs in the Ques- buried placer channels, especiallythose with cemented ne1 belt display only narrow zonesof hornfels. Theseinttu- gravels that are amenable to exploitation by underground sions represent either relatively dry magmas or were mining methods. emplaced at greater depth, generally in the basd sedimentary portion of the arc assemblage. The agesof Ihe deposits LODE DEPOSITS (Table 4-1) and the relationships between the a’ikalic intrusions and their (in part) cogenetic volcanic h(~strocltsare INTRUSION-RELATED DEPOSITS discussed in Chapter4. PORPHYRY COPPER-GOLD DEPOSITS Mount Polley (Cariboo-Bell)Deposit; ASSOCIATED WITH ALKALICINTRUSIONS MINFILE 093Al008 Porphyty copper-golddeposits ofthealkalic class (Barr Mount Polley (formerly Cariboo-Bell) is located 56 et a[., 1976; Mineral Deposit Research Unit (MDRU) cur- kilometres northeast of Williams Lake and 8 kilometres rent studies, reports in preparation, 1996), and the closely southwest of Likely. It lies between Polley Lakeand

BuNetin 97 75 British Coiumbiu

W3A 018 MARY W3A 116 BM W3A 118 ML W3AM SLIDE W3B @2S LYNDA 0938 016 MANDY dyryCUM0 std " W3A 011 FNEV~PEAK) 5798325 W3A 039 WET(GAVMLA$€) 5816765 m3A 076 FS. 5816986 W3A 078 MEGABUCKS 3190666 W3A 079 BEEN 5797361 m3AW WOOD J7W3 093A096 MCKa 1m W3A 117 DOE 5-6 W3A ID DAPHNE 5816269 093BGlI KATE 5871364 W3B 033 NWLAKE 5841175 W3B MI TARN 3841989 STRUCTURALLY CONTROLLED BIESOTHERMAL) DEPOSITS: V-W&sd@~mborhhurlshar~ W3A 149 JA" W3A07W 5m 0938 027 AB W3B16E 58651% W3A m3 PRO- W3AllW 5833S18 W3A 012 zll) W3AOlW 5813961 W3A 013 CPW W3AllW J827413 W3A 072 IOY W~AIZE 1826929 WAC92 FORKS mumw slmm W3A 121 MOOS W~A~E 58W9 W3A 132 NOV W3A11W 5834159 W3A 133 PEACOCK W3*11W 5844165 m31\ ts SHAW W3A12E 58%261 09% 147 TAM W3A11W 5831981 W3A 150 fF.AEXGOW W3AOlE 5197510 093A IS1 BIG W3AllW 5832131 W3.4 154 TRUMP W3AIIW 3833841 0938 029 COUSINJACK W3B16W 5Wl VOLCANIC-HOSTEDCOPPER DEPOSITS:

PLACERDEFUSITS:

76 Geological Survey Branch EN (EUREKA PEMJ WEl IGAVIN MKU F.S MEGABUCKS BREN WOOD MCKEE DOA DWHINE KATE NYUND LAKE TARN

... ..

Y Figure 8-1. Generalized geologicalmap of project area - locations of intrusion-related deposits showing major alkalic porphyry copper-gold prospects. Briiish Columbia

Bootjack Lake at an elevation of about 1250 metres on the breccia and minor pyroxenite and gabbro. Late intrusions, western slopes of Mount Polley.The property is accessible mainly post-mineral dikes, include augite porphyry, feld- from Highway 97 at 150 Mile House byway of 76 kilome- spar porphyry, monzonite porphyry, sanidine monzonite tres of paved road and 14a kilometres forestry access road. porphyry and biotite lamprophyre. To the southwest, the The deposit was discovered in1964 after examination Bootjack stock is exposed at Bootjack Lake. It comprises of trenches with showings ofcopper oxide minerals within pseudoleucite and orbicular syenite prpbyry and grano- a large magnetic anomalyindicated by a federal-provincial phyric nepheline syenite, lithologies similar to those at airborne magneticsurvey of the Quesnelmineral belt Mouse Mountain,IO kilometres to the northwest. Together, (Hcdgson etai., 1976). The initial pit reserves are stated to all these rocks form the largest, and probably the highest be 48.8 million tomes of material with an average gradeof level, alkalic intrusive complex in the Quesnel belt. Hos- 0.38% copper and 0.56 gram per tonne gold (Nikic et ai., trocks for the intrusions are felsic-clast bearing pyroclastic 1995).Revisedorereserves(1995)reportedbythecompany rocks of unit 3. are:81.5milliontonneswith0.30%copperand0.414grams The petrochemistry of the alkalic complex is consid- per tonne gold. The mining reserves are contained in the ered by Langet af.(1993) to be part of an unusual silica-undersaturated subtype of the alkalic suite that includes the West and Central zones(Figure 8-2). withinthe larger Galore Creek and Copper Canyonintrusions in Stikinia and Caribou-Bell zone, a geologicalresource containingaround the Rayfield River intrusions near Bonaparte Lake. The million tonnes with an average gradeof 0.25% copper 230 more common alkalic porphyry deposits in the Cordillera and 0.34 gram per tonne gold (MINFILE). Feasibility stud- are associated with quartz-saturatedor near-saturated alka- ies completed in outline plans for open-pit mining 1990 lic intrusions, referred to by Lang et ai. as the silica-under- from the coalescing Central and West zones ina 5 million saturated subtype. tonne-per-year milling operation. ApprovalPrinciple in was Mineralization and Alteration: Mineralization is granted by the provinical government in June 1991 but associated mainly with hydrothermal and intrusionbreccias in development of the property was suspended a short time the Polley stock. Intrusionbreccia is matrix supported with later when theprice copper dropped. The deposit being of is plagioclase porphyry containing commonly around prepared for production in 35% 1996. subangular to rounded clasts of diorite, plagioclase por- Geology: The deposit is contained largely within the phyry andlapilli tuff. Hydrothermal breccia is polylithc and Polley stock. This intrusion is approximately 2 kilometres contains clasts of intrusive breccia in addition to diorite and by 5 kilometres in size, and elongated in a northwesterly plagioclase porphyry. These breccias commonly occur at direction. The Polley stock consists of mainly diorite, lesser contacts between the variousrocks types. The hydrothermal plagioclase porphyry, intrusion breccia, hydrothermal breccia is vuggy and contains abundant secondary biotite, albite,potassium-feldspar, actinolite, magnetite and diopside. The breccia has extensive stockworks containing chalcopyrite, magnetite, diopside and amphibole. Fraser (1994,1995)recognized three stages of breccia emplacement onthe basis of crosscutting relationships.The oldest is dominated by diorite and minor volcaniclastic clasts in a matrix of plagioclase porphyry. It is cut by polylithic breccia that contains cavities containing chalcopyrite, pyrite,albite, biotite, magnetitie and diopside. These are hydrothermal breccias that contain the best copper and related gold grades. Thelatest breccia is an intrusionbreccia withdistinctivepyroxeniteanddioriteclastsinamonzonitic matrix; it is post-mineralization in age. Late calcite and zeolite in vugsand dilational veins overprint the older alteration products. Ore minerals are chalcopyrite, lesser bornite and rare "m "m nativegold, associated withmagnetiteandminorpyrite.The monzpnite, monzonite porphyry, undifferentiated breccms minerals occur as disseminated grains and fracture and cavity fillings. Copper mineralization is associated with m-.-'* '. ' tntrusion and hydrothermal breccia. minor dioriie ...... and monzonite screens potassium feldspar, biotite and diopside alteration in both the intrusive rocks, breccias and, to a lesser extent, the host volcanic rocks. Peripheral mineralization with outward-de- .""..... creasing chalcopyrite to pyrite ratio is associated with epi- Figure 8-2. Mount. Polley (Caribw-Bell) simplified geologyand dote-garnetand epidote-chloritealteration. Aweakly proposed pit S-19 outlie after Fraser (1994) and Nikic ei ai. developed pyritic haloin propylitic volcanic rocks sur- (1995). Post mineral dikes have been removed. rounds the mineralized intrusions and breccias. Supergene

78 Geological Survey Branch Ministry of Employment and Investment copper minerals are present inparts of the deposit but little nation of diamond-drill cores by Morton (1976). The stock copper enrichment has occurred due to the widespread intrudes a sequence of Upper Triassic pyroxenc: basalts of presence of calcite, albitic plagioclase, prehnite, zeolite unit 2 butis surrounded bybreccias with felsic clasts. These minerals and the overall low sulphide content. Supergene proximal breccias appear to be locally preserved, coeval minerals include malachite. chrysocolla, native copper, rocks of unit 3 that form an apron aroundthe stock. cuprite, digenite,covellite (Nikic et nl., 1995). and probably The volcanic hostrocks surrounding the in;+usion and some brochantite. part of the stock itself, have undergone propylitic alteration Alteration: Studies by Fraser (1994,1995) have iden- characterjzed by widespread developmentof epidote, chlo- tified two distinct alteration assemblages that refine the rite and calcite. Zeolite may also be a related, :nore distal older descriptions. The alteration is now classified as a and later-forming hydrothermal alteration mineral. Locally, copper-gold mineralized calc-potassic type with (central) a mainly within the intrusion, secondary biotite and potas- potassic and intermediate calc-potassic zone and a periph- sium-feldspar alterationis associated withcopp:r minerali- eral propylitic type outside the economic mineralization. zation.The mineralization also occurs sparingly in the The calc-potassic alteration is characterized by potassium- volcanic hostrocks as chalcopyrite, magnetite, pyrite and feldspar, biotite, diopside, albite, magnetite, lesser actinolitepyrrhotite. The best samples fromsurface trenches reported and minor garnet. Garnet alteration occurs mainly in two in 1984 returned assays of 0.25% copper over 21.3 metres. zones at the periphery of the proposed pit. The andradite garnet in the West zone is associated withintense albite and Kwun Lake; MINFILE 093M077 and potassium-feldspar alteration in a hydrothermal breccia.In Beehive (Beekeeper); MINFILE 093A/155 the Central zone, massive garentis overprinted by magen- The Kwun Lake showing, and Beehivemenmy occur- tite, diopside and epidote (Fraser, 1994). The peripheral rence, about1.5 kilometres to the southeast, occur about7.5 propylitic alteration is characterized by pyrite,epidote and kilometres north of Horsefly. They are associabd wifh the albite. Pyrite is rare overall; its concentration rarely exceeds Kwun Lake stock, a small, zoned diorite to syenodiorite 1% except in a pyritic halo alongthe northeast and south- intrusion typical of Quesnel belt alkalic plutons. The stock west margins theof calc-potassic zone where to up 6% pyrite is in contact with breccias of unit3 on three sides. Cm the has been noted. western side, the stock and thefelsic breccias are separated Summary: Mount Polley is typical of many porphyry from older pyroxene basalts by faults. Along lhis faulted deposits with a central potassically-altered core with chal- margin of the stock the rocks are locally hydlothennally copyrite, magnetite, lesser bornite and minor pyrite miner- altered by secondary potassium-feldspar and biotite, up- alization.The surrounding rocks showwidespread sum and more widespread propylitic assemblages charac- propylitic alteration characterized by an epidotepyrite-al- terized by epidote, chlorite and calcite. Minera1iz:ation bite assemblage. A locally developed, intermediate zone consisits of small amounts of chalcopyrite,pyrite and rare contains garnet. It formed together with albite, younger bornite inbrecciated zones.The propylitically altered rocks potassiumfeldspar and albite and isoverprinted by are more sparsely mineralized, but they typically contain magnetite, diopside, epidote. calcite, chlorite, pyrite, chal- abundanthydrothermal magnetite. A small zone 3 to 6 copyrite and zeolites. The Polley stockis part of an intrusive metres wide in a monzonitic hostrock. tested by diamond alkaliccomplex comprising various medium-grainedtopor- drilling, contains from 0.4 to 1 gram per tonne $:old. phyritic intrusions and brecciasthat are emplaced into vol- The Beekeeper zone near the eastern margin of the canics of common petrogenetic lineage. Fraser (1994)states Kwun Lake stock hasmineralization typical of elsewhere in that the middle ofthree breccias is associated with the main the stock. comprising chalcopyrite, pyrite and pyrrhotite, zone of mineralization. The emplacement of breccias and with anomalous gold values. The sulphide minerals 'occur the intrusions was structurally controlled. North to north- as disseminations andfracture fillings associatd witb pink northwest-trending faults separate the complex into two potassium-feldspar and calcite-epidote-chlorite alteration. mineralized zones. Each zone has distinctive alteration and Asecond periodof mineralization superimposed onthe: first, mineralization assemblages;together they consitutethe ore- is characterized by cinnabar, ankerite, fluorite ,and quartz. body at the proposed pit site. The younger episode formed veins and fracbxe fillings spatially associated with syenitic hornblendeporphyry PORPHYRY COPPER-GOLD PROSPECTS dikes, part ofthe Kwun Lake intrusive suite.Up to several ASSOCIATED WITH ALKALIC STOCKS percent mercury has been reported from some samples(see also Appendix M, 1986-AX8). Lemon Lake (Pine, Fly, Lem); MINF1L.E 093M002 Copper mineralization in basaltic rocks sirnilar IOthe TheLemonLakeprospect, IOkilometreseast-northeast KwunLake prospect, and associated with other a'lkalic of Horsefly and a few kilometres south of Horsefly is Lake intrusions, is also present 3 to 5 kilometres to the norh At the most southerly of the known alkalic copper-gold pros- the HOOK (MINFILE 093M112) and BM (MINFILE pects in the Quesnel belt. It is associated with a poorly 093N116) properties pyrite and chalcopyrite in propyliti- exposed diorite to monzonite stock in which multiple intru- cally-altered basalts appearto be related to small intrusions sive phases have been recognized from mapping and exami-or a number of dikes of monzoniteor syenite.

Bulletin 97 79 British Columbia

Shiko Lake (Redgold); MINFILE 093M058 QR (Quesnel River)Deposit; MINFILE 093M121 The QR deposit is near the north bank of the Quesnel A zoned, medium-grained diorite to monzonite stock, River 58 kilometres southeast of Quesnel and10 kilometres locally with coarse-grainedsyenite dikes and granophyric- textured to pegmatitic zones, hosts chalcopyritepyrite west of Quesnel Forks. It was located in 1975 byFox Geological Consultants Limitedby tracing gold, arsenic and bornite mineralization. The stock is about 2.3 kilometres other metal geochemical dispersion anomaliesglacial in till. long ina northeast direction.It intrudes the youngest basaltic Percussion drilling 1911in outlined the Main zone; the West rocks of unit 2 in the eastbut to thewest is emplaced in,or zone was discovered in 1983 and the Midwestzone in 1986. in fault contact with, breccias and sedimentary rocksof unit Mineable reserves inthree zones are1.3 million tonnes with 3. An embayment along the southern part ofthe stock 4.7 grams per tonne gold (Fox and Cameron, 1995). This contains breccias with volcanic clasts and grades into an deposit represents a new type of bulk-mineable goldoccur- intrusion breccia withdiorite matrix closer to the stock. This rence in the Canadian Cordillera - a porphyry-related breccia appears to mark the intrusive centre of an intrusive- propylite skam gold deposit. extrusive magmatic vent. The mine was officially opened inSeptember 1995. A fiveyear mine life with production ofloo0 tonnes per day Bullion Lode; MlNFlLE 093M041 is planned, starting with open-pit mining of the Main and An equiganular to porphyritic, medium-grained pink part of the West zone followedby underground mining in monzonite intrudes fine-grained diorite in the area of the the West zone. Conventional millingwith gravity separation Bullion placer mine where a number of the dikes and the to recover much of the gold, and carbon-in-pulp cyanide contact of the pink monzonite are exposed in the western leaching with electrowinning and on-siterefining of ‘dore’ part of the pit. The main monzoniticbody is emplaced to the bars, are being used toextract the gold and minor associated west and north of the Bullion pit in pyroxene basalt hos- silver. Additional reserves are confirmedat depth to the east trocks of unit 2. Widespread pyrite withrare chalcopyrite is of the Main zone. present; locally there are concentrations of magnetite. The Geology: Three main mk-types, part of unit 2a and eastern part of the Bullion stock contains the Likely Mag- 2aI2d. underlie the property: basalt, calcareous tuff and netite iron-gold-copper showings (MINFILE 093A1084). mudstone. Stratastrike east and dip moderately to the south Rare bornite was noted in basaltic hostrock on the south The lower unitis comprised of at least 850 metres of alkalic bank of the Quesnel River. basalt, mainly monolithological breccias,pillow basalt, massive flows and volcanic sandstone. The overlying, middle unit is made upof basaltic-source tuffs or epiclastic rock Others from 5 to 80 metresin thickness. These rocks have a A number of other alkalic stocks in the Quesnel belt calcite-rich matrixand contain from 5 to 20%pyrite which have been examined for their porphyry copper-gold poten- has framboidal, colloform and bandedtextures. The upper- tial (Figure 8-1). The deposits include: Maud Lake(MIN- most unit is a 200-metres thick sequence of thin bedded FILE 93A/119), Mouse Mountain (MINFILE 93G/005) and mudstone and silstones.It contains up to 10%finegrained the Cantin Creek and Gerimi Creek prospectsin NTS 93B disseminated pyrite and is altered to rusty weathering horn- that are not codedin MINFLLE. A few, suchas Cantin Creek fels neartheQR stock. Thestockmeasures 1 by 1.5 kilome- and Mouse Mountainare associated with mafic rocks of the tres. The intrusion is similar to the other Early Jurassic, alkalic intrusive suite such as gabbro and pyroxenite, in compositionally zoned, alkalicdiorite stocks in the Quesnel addition to diorite and monzonite. Some of themafic rocks belt. It consists of a 100 metres wide medium grained, are reportedly serpentinid, suggesting that some of the equigranular diorite margin, that surroundsa core of mon- inmsion may be emplaced along large, possibly regional- zonite and rare syenite. Hornblende porphyry dikes sills and scale, structural breaks. The prospects have been covered are common, notably surroundingthe QR stock. by assessment reports filed with the Ministry of Energy, Alteration and Mineralization: The QR stock is sur- Mines and Petroleum Resources,but little or no other infor- rounded by a zone of hornfels and propylitized rock that mation has been issued. extends up to 300 metres into the sumundingtuff beds. The mineralization occurs in propylitized, carbonate-altered PROPYLITE GOLD DEPOSITS fragmental basalt alongthe contact with the overlying siltstones near the northern contact of the stock. The basalts are The type deposit from which a model for ‘Propylite extensively altered by chlorite, epidote and carbonate min- gold’ deposits has been createdis the QR (Quesnel River) erals and contain1 to 15% pyrite. Fox and Cameron (1995) prospect. It has alternatively been described asan alkaline describe the basaltic tuffas being variablypropylitized and copper-gold porphyry-related replacement depositby Fox “skarn-altered”. Othersulphide minerals, mainly chalcopy- et al. (1987). Fox (1991). Melling and Watkinson (1988), rite, can form upto 5% of the rock but the sulphide content Melling et al. (1990), anda skam (Fox and Cameron, 1995). is generally much less than 1%. Gold is present as small Alternate termspropsed for this deposit type are skamoid, particles along pyrite and chalcopyrite grain boundaries. manto and epidote skarn. Best gradesare found within50 meVes of the altered basalt-

80 Geological SurveyBranch Ministry Employment and hvesfment of ” siltstone contact in altered tuffs that Fox and Cameron term Related dikes and sills in the mineralized zonese.xternd to epidote-rich skarn and sulphide-rich mantos. A map and the stock may be more extensively hydr0therma:lyalb:red cross-sections showing the three ore zones is shown on than the main intrusion. Figures 8-3 and 84. Mineralizationand Alteration: Propylitic zones %with The PropyliteModel aurifeous pyrite occur withinthe propylitic alteration aureole. The better grades are generally at the outer periphexy of Rock Types: Epidote and pyrite-rich auriferous the propylitic alteration zone, commonly at lithologic unit propylitic alteration (epidote-chlorite-tremolite-calciteand or bedding contacts. Tabular, conformable mantosform may rare garnet), with minor other sulphide minerals, occurs as in permeable beds and units, commonly along tlle contact lithologically controlled, conformable replacement zones between hornfels or other less permeable rocks and the within a thermal aureole adjacent to an intrusive body. propylitic fragmental volcanic rocks.Faults or olher, omlder Hostrocks are hornfels and epidote-rich propylite derived structural features may be mineralized and formore zones from mafic volcanics, commonly withalkalic (shoshonitic) that are transgressive to strata. compositions,mafic tuffs and volcanic sandstones and calcareous mudstone. Intrusions are generally small, zoned Pervasive propylitic alteration of the matrix and clast stocks with diorite to syenite compositions. Their age is rims of fragmental volcanic rocks is characterinxl by dis- similar to, or slightlty younger than, their hostrockalkalic seminated grains or intergrowths of epidote with chlorite, volcanics. Feldspathic hornblende porphyry dikes and sills calcite, tremolite, quartz, albitic plagioclase, clinozoisite are common. The stocks exhibit little alteration but have a and rare andradite garnet. Calcite is abundant pelipheridto weakly developed porphyry copper-style mineralization. the propylitic alteration zone and in the mudstone beds.

Figure 8-3. Geology of the QR gold deposit after Fox and Cameron (1995). Cross-sections of the three ore zones an shown on Figure 84.

” BuNetin 97 8I British Columbia

Fracture controlled quartz-sencitepyrite zones may occur in subordinate amounts. Granular pyrite-epidote-calcite aggregatesreplace the matrix of the volcaniclastic rocks and clast rims. Locally pods and lenses contain up to 80% pyrite and other me sulphide grains. F'yrite also occnrs as fractnre coatings, seams and veinlets with calcite and epidote. It is the , ...... predominant sulphide mineral; the ore mineral is gold. , ...... Subordinatemiueralsarechalcopyrite,pyrrhotite,sphalerite and marcasite withminorgalena, andarsenopyrite.Magnet- ...... ite may be present as a constituent in some sulphide-rich bands. Gangue mineralsin addition to the abundant epidote, chlorite and calcite are tremolite, quartz, clinozoisite and rare andradite garnet. Permeability in the volcaniclastic rocks is a fundamental ore control; secondary controls are ...... tectonic breccias, faults and fracture zones that provide additional fluid flow paths. Chemicallyreactive hostrocks N containing calcite, sulphide minerals or devitrified glass may cause ore deposition by chemically buffering the hydrothermal solutions. Origin: The QR deposit is related to a small, relatively "dry-looking", zoned alkalic stock. Fox (1989, 1991) has described the deposit as a "failed" porphyry system. He suggests that goldis transported by a magmatic-source low density, low-sdinity fluid rich in COz. The writers consider the deposit tobe a product of a small geothermal cell with an evolving hydrothermal fluid. A magmatically derived fluid interacted with meteoric water and the mixture evolved, probably through fluid-wallrock interaction with the chemically reactive calcareous siltstones. Mellinger al. (1990) provide isotopic data that are consistent with other porphyry copper magmaticsystems but some modification N C. WEST ZONE in carbon by wallrock interaction is indicated. The early alteration is associated withcalcite (note the zeolite mineral wairakite should form thisin environment but hasnot been recognized), then the COz-depleted fluid reacts with the basalts to form propylite - mainly epidote, pyrite, chlorite and (?) tremolite with rare andradite garnet. This is not a retrogressively altered skarn because maximum temperatures of mineralization appear to be in the order of 200 to 300°C. This low temperature produces prograde propylite mineral assemblages without any substantial amount of calc-silicate andsilicate minerals typical of goldskarns such as garnet, pyroxene, wollastonite, vesuvianite, axinite,potassium-feldspar and biotite. Exploration Guides: A distinctly anomalous geo- , chemical signature of gold, arsenic, silver and copper are Drill hole showing mtersectionin metres typically associated with ore. Pathfinder elements in the 7Sm andgod tenor in 6.W' gr0ms)bnne hydrothermally altered rocks include zinc, molybdenum, Epidote vanadium, antimony and possiblylead, cadmium, bismuth, skorn Gold zone / cobalt, magnesium andiron (Fox et aL, 1987). Glacial till, soil and vegetation exploration geochemishy have been Figure 8-4. Cross-secrions of the QR gold depositMain, Midwest used effectively in this region of extensive glacial disper- and West 0% zones after Fox and Cameron (1995); locations are sion. Magetic surveys have beeneffective exploration tools. shown on Fignre 8-3. Aeromagnetic highs canbe used to detect the presence of intrusions, mainly the magnetite-rich dioritic stocks with which the propylitic alteration is associated. Some of the

82 Geological Survey Branch Ministry of Employment and investment ” porphyry copper mineralization contains abundanthy- stocks are composed of quartz-phyric granodioritt:to quartz drothermally derived magnetite. monzonitewith large quam grains in fine to medium- Genetically affiliated mineralization may be manifest grained, leucocratic alaskite to aplite groundmass. This as intrusion-related auriferousvein, replacement and pyrite- younger intrusive suite commonly carries some porphyry- sericite stockworks, manto and skarn deposits and porphyrystyle molybdenite mineralization. Other Cretaceous intru- copper-gold or porphyry gold deposits, all in propylitic sions with related molybdenum or molybdenum-copper settings. Other deposits with similarities to the QR deposit mineralization are the Gavin Lakestock and related are the 66 zone at theMiUigan porphyry copper-gold deposit deposits, the copper-molybdenum prospects in the large in British Columbia, and elswhere the mantos suchas Can- Nyland Lake stock nearthe Quesnel River in the northem delaria and Puntadel Cobre, Chile. part of the map area, and EN (Eureka Peak), F.S., Wood, Discussion: The QR deposit and propylite gold depos- Dor, Daphne,Kate and Tam prospects. Other probably its in general) appear to be related to mineralization by a intrusion-related depositsare the Bren and Mckeeprospcts (relatively) small volume of ‘ponded hydrothermal fluid’ and some replacements and veins such as the Jamboree related to emplacement of a small alkalic stock. There has (Table 8-1; Figure 8-1). been considerable interaction with (‘buffering’ by) the basaltic country rock to form abundantepidote and pyrite but AURIFEROUS QUARTZ VEINS IN no substantial amount of skarn. The hydrothermal system METASEDIMENTARY BLACK PHYLLI1“E exemplifiesa lithologicallyand structurally controlled min- UNITS eralizing process in which adjacent permeable and imper- The Triassic black phyllites of unit 1 host auriferous meable lithologies form a fluid trap against a small, quartz veins of two main types(Figure 8-5). Thefirst type, mineralizingintrusion. The West zone,on the other hand, is characterized by the Frasergold deposit, compris:s the par- largely a structural trap and forms a discrete, copper-rich tially concordant, deformed, early forming veins that are zone. localized in a distinctive stratigraphic interval.The second This type of propylitic alteration can be considered to type is represented by fracture-controlled vein niineraliza- be a subtype ofskam mineralization - a prograde, low-tem- tion thatis associated with quartz-carbonate altemtion, ,such perature, auriferous epidote skam. Unusual aspects that set as that in the Spanish Mountain area. The twcs styles of the pmpylite model apart from other auriferous skarns are mineralization are thought to be similar in ageand re1,ated (G.E. Ray, personal communication,1994): the association to deformation during regional metamorphism but the :frac- with alkalic rocks; the large amount of epidote with lack of ture-controlled type maybe younger. pyroxene and only traces of garnet; mineralization with pyrite, lesser magnetite and rare pyrrhotite suggesting an Frasergold Prop*; MINFILE 093M150 oxidized ore fluid; the high gold to silver ratio and overall TheFrasergold property is locatedon north-facing low coppercontent slopes in the upper reaches of the McKay River valley This style of mineralization deserves to be identifiedas (Figure 8-6). approximately 57 and 100 kilometres east of a deposit type that is distinct from the gold skarn model Horsefly and Williams Lake, respectively. Gold on this largely becauseit represents a new exploration opportunity. property occurs in quartz veins andas a geochemical enrich- The mineralization hasan unspectacular appearance in out- ment in aspecific lithological unit withinthe Nicola Group crop and generally has not heen highly regarded as an basal sedimentary succession,unit 1 (Figure 8-5). The veins exploration prospect. Many pyritic propylite occurrences, are localized in distinctive porphyrohlastic phyllites with especially those in porphyry copper districts. might have underlying graphitic banded phyllites in the basal100 me- been excluded from further investigation of their goldcon- tres of a 300-metre succession oflustrous porphymblastic tent. phyllite. The siderite, ankerite and chloritoid-bearing hostrocks, commonly referredto as‘knotted phyllitc’,are part PORPHYRY MOLYBDENUM, AND COPPER of Bloodgood’s (1987a)unit Tra4. The veins arc: localized DEPOSITS AND RELATED VEINSASSOCIATED in this unit over a distance ofat least 1.5 ki1omt:tres along WITH CALCALKALINE STOCKS themoderately southwest dipping northern limb of the Quartz-bearing, calcalkaline intrusions occur in the Eureka Peak syncline. Equivalent rocks becan Wtced tco the map area as both large plutons and smallstocks. They form southern limb of the syncline where they contnin garnet, two distinctive suites of rocks in terms of composition and albite and chloritoid. age, as discussed in Chapter 3. Early Jurassic rocks are Bedding attitudes trend northwest with 40 to 50” dips represented by the Takomkanebatholith, a medium to to the southwest. Bedsare defined by thin quartz.sandr;tone coarse-grained granodiorite with syenodiorite andpor- layers, 0.5 to 10 centimetres thick. A penetrative phyllitic phyritic biotite-bearing phases. Molybdenum mineraliza- foliation is developed axial planar to tight isoclinal folds. tion inthe stock at the past-producing Boss Mountain mine The porphyroblasts, which range insize from 1to 20 milli- (MINFILE 093A 001). 43 kilometres to the southeast of metres,arecommonlyflattenedwithintheplanecffoliation. Horsefly, is related to a small, late Early Cretaceous intru- The SI schistosity strikes 130” and dips 55 to 60” to the sion,theBossmountainstock.ThisandtheotherCretaceous southwest. In many places bedding has been tranr.poseclinto

Bulletin 97 83 Figure 8-5. Generalized geological map of project area showing locations of suucturally controlled, mainly (mesothermal)vein deposits. Minisfry of Employnew ond hwestmenf " and obliteratedby the SIfoliation. An S2 crenulation cleav- in phyllite suggest that some remobilization took place age is subparallel to SI. It trends 115 to 120° and dips during folding. southwesterly at 70 to 85'. The formation of the quartz veins was synt:hnous Auriferous quartz veins with some carbonate range with regional metamorphism and deformation.A smpIe of from 2 to 20 centrimetres in thickness and usually extend hydrothermal sericite from a quartz vein in the Main zone from 1 to 10 metres along strike. They are generally parallel,yielded a K-Ar date of 15 16Ma (see Table 4-2 fol: analyti- or nearly so, to So and Si structures and form lenses,rolls cal data). Deformed and undeformed veins occir on all and saddle reefs(see Figure 6-3). A few largerods or quartz scales,alongthelimbsandwithinthehingeregionsoffolds. knots up toa metre across are also present (photo 8-1). The Some of the vein fillings are probably products offaids that quartz is generally miIky white in coIour and forms massivewere generated during dewatering reactions duringthe Late to coarse granular intergrowths commonly containing dolo-Jurassic metamorphicevent. The fluidsmigrated along mite and siderite.The veins also contain a small amount of cleavage surfaces and deposited the vein constituents in pyrite, less common pyrrhotite andtraces of other sulphide dilational zones. minerals. Gold is associated withthe sulphide minerals or The lithological control, possibly through fluid-rwk occurs in quartz near the margins of veins, stringers and interactions in the graphitic sedimentary rocks, has yro- boudins as fine, anhedral grains. Gold smearson fold hinges duced a zone of geochemical gold enrichment isthat defined

J Figure 8-6. Frasergold property work areas, claim boundary and geochemical gold anomaly in soils; Eureka Rewurces Inc. companyrepon, 1592.

BuNetin 97 85 by asoil and rock geochemical anomalyIO kilometres long Gold is frequently visible as fine particles rimming cavities (Figure 8-5). Company reprts (EurekaResources Inc., or as wires where sulphide minerals are oxidized. 'bo J. Kerr, written communication, 1992) that summarize the mineralized zones identified by F'undata Gold Corporation economic potential state that drilling at 25-metre intervals are estimated to collectively contain 838 000 tonnes of and to a depth of 100 metres over an 800-metre zone has materialwitbanaveragegradeof1.95gramspertonnegold; established reserves in the order of 3.2 million tonnes con- more recent work hasnot substantiated this estimate. taining 1.71 gramsper tonne gold. Drilling at wider The fracture-controlledstyle of the mineralizationsug- intervals, over 3-kilometrea strike length, indicates mineral gests that the veins and stockworkpostdate metamorphism reserves with similar gold content in a larger zone are and deformation. Theproperties are located onthe northeast possibly amenableto open-pit mining. Exploration potential limb of a northwest-trending anticline that is cut by numer- at depth and over an additional 7-kilometre strike of the ous northwesterly trending, syndeformationalthrust faults. anomalous zone remainsto be tested. The lithologic units and northwest-trending structures are crosscut by aseries of prominentnortheast to east-trending Spanish Mountain Deposits - CPW (Mariner) and Peso normal faults. These crosscutting structures and faults Claims; MINFILE 093A/043 control the mineralization. Quartz veins containing gold and minor base metals occur to the southwest of Spanish Lake, about7 kilometres TERTIARY BEDROCKDEPOSITS southeast of Likely. The main lithologies in the area are phyllitic to massive siltstones and interbedded tuffs. Much Megabucks Property; MINFILE 093A/078 of thearea is affected bypervasive carbonatesilica replace- The Megabucks copper-gold prospectis underlain pre- ments and listwanite (greenmica - quartz - carbonate) dominantly by Eocenevolcaniclastic rocks, feldspar-phyric alteration associated with quartz veins or fractures. In the ash flows and possibly some coeval hornblende porphyry more intensely altered zones there are quartz stockworks dikes. Some of the property coversgranodiorite of the Early and larger veins, a number of which define a consistent Jurassic Takomkane batholith. A large part of the area is northeasttoeasttrend.Goldoccursinthequartzveinswhich covered by a mantle glacial of till, fluvioglacialdeposits and range in thickness from 0.01 to 4 metres, dip steeply and small outliers of Miocene basalt; older bedrock is rarely trend to the northeast. The veinsare typically crystalline to exposed. vuggy quartz with lesser carbonate intergrowths and asso- The Discovery zone is in silicified and propylitized ciated minor galena, chalcopyrite, pyrite and sphalerite. Eocene hornblende feldspar porphyry flows and breccia.

Photo 8-1. Typical auriferous quartz veins at the Frasergold property exposedby stripping of thin overburden lo facilitate mapping and sampling of quartz and the surrounding phyllitic hosmks. The veins are discontinuous along strike; commonly the larger massesof quartz occur as boudins.

86 Geological Survey Branch Also present are purple and tan-coloured lapilli tuffs and OTHER DEPOSITS buff to grey tuffaceous sediments.The silicifed rocks con- Other mineral deposits in the study area listed and tain epidote as blebs and stockworkfillings with magnetite m: shown on Figure 8-7. They include three occLIrreno5s of and chalcopyrite,Pyrite is rare to absent in this association. native copper in Nicola volcanics and related ckalcocite in Gold appears be intimately associated with chalcopyrite. to nearby calcareous andfine-grained clastic sc:dimentary Drilling during 1983 and 1984 has outlined about750 000 units. Thereare two occurrencesin ultramaficrmks, one an tonnes containing 0.15% copper and 1.37 grams gold per asbestos showing, theother contains talc, nickel and other tonne. Some recent drilling records itercepts of 30 metres metals in shear zones.TheEagletfluorite and silverprospect with 1.2 grams per tonne 48 and metres with 0.64 gram gold consists of a series of steeply-dipping mineralized zone per tonne (Campbell, 1984). believed to be typical of the within a 1500 by 900-metrearea in gneissic and pegmatitic mineralization. rocks ofthe Snowshoe Group. The Kusk property is a The mineralized rocks are found in faulted and sheared gold-silver prospect described as a stratabound zone of zones in which beds have steeper dips than the regional quartz and carbonate-altered and quartz-veined phyllites. norm. This suggests that they occur at, or near the margin The Horsefly silica deposit consists of a large zone within of a grabenor other structurally controlled depression.The the Eocene volcanic succession of poorly indurated sili- mcks are the most strongly altered with pervasive bleachingceous volcanic ash. due to mainly carbonate-sericite-clay alteration. Pyite with lesser chalcopyrite is disseminated and occurs in veinlets. PLACER GOLD DEPOSITS OF In the central mineralized zone gold is associated with the chalcopyrite,To the southwest there is a pyrite halo partially HORSEFLY AND QUESNEL RIVER delineated by drilling that appears to surround the copper- DISTRICT gold zone. Records of gold mining in the Quesnel River area date In the southern part of the property, mediuma to coarse- back to the earliest history of placer mining in British the Early grained granodiorite that seemingly is part of Columbia. There is mention as early as 1852 .of natives Jurassic Takomkane batholith, andthe overlapping Eocene trading gold nuggets from unknownsources at thc Hud!ion’s tuffaceous rocks, are altered by an assemblage of tourma- Bay Company trading post at Kamloops. The mining of line, sericite and abundant fine-grained pyrite. This altera- substantialamounts of placer goldbegan in 1857 in a tion commonly consists of vuggy, fine to medium-grained tributary of the Thompson River and led to art influx of masses of radiating black tourmaline needles. Similarlyin several thousand miners into the Fraser River valley and the northenpart of the property and3.5 kilometres southeast areas in the south of the province. A number of the more of Starlike Lake, the Eocene tuffaceous rocks have sericite- adventurous prospectors worked up the Frase:Rivt?r in pyrite assemblages in zones of bleached, siliceous pyritized search of new placers and possibly the lode gold sources. rocks containing tourmaline-bearing fractures and veins. Their continued prospectingefforts took themup the Ques- Peripheral to the tourmalinized rocks, mainly in the older ne1 River to what is now Quesnel Forks. Rich river-bar pnodioriteand possibly homfelsicTriassicvolcanic rocks, placer gold was foundthere in 1859. During thal time,five propylitized rocks contain pyritic quartz-sericite stock- men led by two natives, proceeded up through Quesnel Lake works and extensive zones with pervasive replacement of totheHorseflyRiveranditsconflucncewithLittleHonefly mafic minerals bychlorite, epidote and disseminatedgrains River. There they reponedly tookout 101 ouncesof gold in of pyrite. oneweekbeforetheonsetofthewinter(Carmichleel,1931). The news of the rich placers in the Cariboo travl:lled Possible Epifbennal Targets quickly and the great Cariboo gold rush began. In 1860, prospectors worked from Quesnel Forks up the north fork Vuggy, chalcedonic quartz-carbonate veins with ele- of the Quesnel River (now the Cariboo River) as far as vated values of arsenic, barium and antimony (see Figure CaribooLake.RichplacerwasfoundonKeithley,~ndAntler 8-7; Appendix M) outcrop on the Horsefly River near Hob-creeks. The next season saw further prospecting up the son’spitatthedownstreamendof ‘TheSteps’areainNicola creeks and over the divide into Williams Creek. The pbe- basalts. Similar veinlets and quartz stockworks, with rare nomenal richness ofthe gravels in this creek su~passedall amethystine quartz, werealso noted along Hazeltine Creek the previous diggings to date. Nearly a thousand miners in the Eocene rocks. A fault zone north of Robert Lake in flooded the area and greatly expanded the wor,dngs. For the Beaver Creek valleycontains altered rocks with vuggy four years the surfacegravels produced unheardof amcunts texture and open-space filling carbonate and chalcedonic of gold, approximately $2,000,000 worth (117 647 ounces quartz: representative samples returned silver values to 70 at $17.00 per fine ounce). Active placer mining continued ppm silver with anomalous lead, arsenic, mercury and bar- through to the late 1930s, evolving through mmy mining ium. The vuggy textures, banded chalcedony, crustified methods.By 1945, a recorded 827 741 ouncw of gold calcite, as well as the association of metals noted above,is recoveredfrom the Cariboo goldfields (Hollaud,1950). characteristic of epithennal mineralization. These production figures represent only recorded produc-

” Bulletin 97 87 Volcanic-hosted Copper Occurrences MlNFlLE NO. MlNFllE Name CMlmodiiy 083A 088 B -rime CWW,chatcocne 083A OM RED -~1keCOW% chalcoclle 083A 075 MOFFAT -native EOPPM. chalCoclle Other Occurrences MlNFlLE Na MlNFlLE Nam 083A ill3 SOVEREIGNCREEK -IaIc. NI A& ZR Au 083A 046 EAQLET -fluom* A0 081 KUSK 083A 081 -Aq AS 093A 138 FONTAINE CREEK -B*wstoB 083A 134 HORSEFLY -.IIIEB As - Sb - 8e 4-Ap Epltkmsl? lndlcstlom (sea wpendlx M N for locallw) xA - HwsefEl R.iP8s-AXla AP87-AX6 xB - Hazelline Ck AP07-AX24 AP87-AX28 xC - faun zone AP87-AX17 Td AP87-AX22

I - ,WOW

Figure 8-7. Generalized geological map of project area showing locationsof volcanic-hosted native copper occurrencesand other mineral deposits. Figure 8-8. Generalized geologicalmap of project area showing locationsof placer gold deposits. British Columbia tion. It is estimated that total production between 2.5 and3 The Miocene deposits overlie either Eocene volcanic million ounces of gold has been achieved in the Cariboo or sedimentary rocksor, less commonly, the Triassic-Juras- district, more than any other placer area in the province sic Nicola rocks. The sedimentary rocks form a succession (B.C. Department of MinesBulletin 21,1946; Levson and of thinly beddedto laminated andfrequently varved Eocene Giles, 1993). The main activity took place in the Wells- lacustrine sediments at least 150 metres-thick. Abundant Barkerville, LightningCreek, Keithley Creek, Quesnel fossils found inthe sediments include fish and leaves as well Forks - Likely and Horsefly River regions. Theseareas are as pollens, seeds and spores. Fossil fish (Amyzon aggre- still being workedfor placer gold, thoughat a much reduced gatum, Eohiodon rosei) have been dated at 50 to 45 Ma scale. The surficial geology of the Caribdistrict and the (Wilson, 1977). Palynology (AppendixD) corroborates the origins of the placer deposits have been recently described Middle Eocene age of the sediments. The lacustrine sedi- byLevsonandGiles(1993)andEylesandKocsis(1988a,b; ments now in large part occupy the Horsefly River valley 1989). indicating that this has been a long-livedtopographic low. Locations ofplacer deposits in the study area. as noted This feature is probably caused by north to northwesterly byHolland(1950),LevsonandGiles(1993)andtheanthors, trending Eocene structures that formed a system of grabens this study, are shown on Figure 8-8. Most are described in alongorobliquetothetrendoftheTriassic-Jurassicvolcanic MINFILE. Fifteen additional sites are listed by name onthe arc. Above andadjacentto thelacustrine sediments are small figure, including at least five sites on benches above the outliers of biotite-bearing trachybasalt flows and andesitic upper Quesnel Rivercollectively referred to as the Quesnel to trachyaudesitic crystal ash tuffs dated at 52.221.8 Ma River SouthFork depits. Sixty-one of the deposits in the (Table 4-1).Abundant detritalbiotite in the basal part of the CariWQuesnel-Horsefly area have recently been studied lacustrine sequence, andthin ash layers in the unit, indicate by Levson and Giles (1993). They describe the paleogeo- Contemporaneous deposition during the Middle Eocene. morphic settings and depositional environments including: Capping theEocene sedimentary sequenceis a 100-me- buried paleochannels; buried, braided streams and wander- tre section of Miocene flood basalts. Thebasalts have been ing, gravel-bed river deposits; and surficialdeposits. Levson dated at Gravel Creekto be 14.659.5 Ma(this study) but, in and Giles also assess the placer potential and classify indi- the region, range from 16 to 9 Ma and younger (Mathews, vidual deposits in terms of: buried Tertiary placers; pa- 1989). They extend from Beaver toCreek the west and south leogulch placersin high-relief areas; pre-Lafe Wisconsinan, beyond the area mapped and form a continuous plateau large paleochannel deposits; Late Wisconsinan glacial and covering with its base at approximately 850 metres eleva- glacioflnvial placers; late glacial and postglacial, high to tion. Locally the basalts formsmall hilltop-cappings thatare intermediate-level terrace placers; Holocene,low-level outliers from the main body. Thisindicates the basalts were terrace placers; and postglacial colluvial and alluvial fan originally more extensive but their margin hasbeen eroded deposits. along the Horsefly - Qnesnel River drainage system. Sandwiched locally betweenthe Eocene sediments and GEOLBGY OF THEHORSEFLY RIVER the Miocene flood basalts are Miocene fluvial deposits. PLACER FIELDS They form the “Miocene channel” referred to by the early The placer gold that occurs in the Horsefly and parts of miners, that hosts the Horsefly placer gold. Two distinct the Quesnel River watershed differs from mostof the other channels havebeen identified by mapping in the area (Lay, placer deposits in the Quesnel River workings andthe more 1931). based largely on theexcavations and workingsof the extensive Carib goldfields to the north. Many of the pioneer placer miners.The fluvial channels are filled with a Horsefly deposits are buried Tertiary placers, probably Mio-distinctive white quartz pebble to cobbleconglomerate. The cene in age, and predate the Carib00 placers by about 14 quartz appears to be derived in large part, if not entirely, million years. The Carib00 placers represent mainly a post-from qnmveins. In places the basal 1 to 3 metres of the glacial reworking ofolder placers or erosion of original lode gravels has been cemented and indurated calcite by to form gold deposits (Johnston and Uglow, 1926,1933; Levson anda natural concrete. The rocks were sufficiently strong to Giles, 1993). The Horsefly placers are contained in fluvial support fairly extensive undergroundopenings in some gravels under Miocene basalt flows and have an undeter- workings. mined source to the east. The Quesnel River and tributary The main Miocene channelfollows the Horsefly River creek placer deposits are classified by Levson and Giles valley down from Black Creek through Horsefly village.It (1993) as varieties of paleogulch placers, pre-Late Wis- has been found to be up to 150 metres deep and upto 610 consinan, large paeochanneldeposits or late glacial to post- metres across (Lay, 1931, p. A97). The channel sweeps to glacial deposits that occur as high to intermediate-level the west fromthe Horsefly River inthe vicinity of Hobson’s bench deposits or temce gravels. Thereare also postglacial placer workings and runs through Antoine Lake and then colluvium and alluvial fan deposits, Holocene low-level into the Beaver Creek valley (Figure 8-9). The second terrace placers and reworked,generally small, creek-bottom channel, smaller than the first, is to the south and west ofthe deposits in which the gold has been concentratedor recon- main channel. The Tertiary gravels are exposed on Moffat centrated in the modem fluvial systems during postglacial Creek below Big MoffatFalls as typical quartz-clast fluvial stream erosion. channel gravels capped by Miocene flood basalts. Some

90 Geological Survey Branch Ministry of Employment and Investment

Figure 8-9. Placer channels in the Quesnel Lake ~ Horsefly River district. The oldest placer deposits are the Tertiary paleachanne:lsof the Miocene Horsefly River and subsidiary Gravel-Moffat-Mussel creeksfluvial systems that have a postulated gold source-area near the Quesnellia-Barkerville terrane boundary near thearea of high-grade metamorphic rocks. TheQuesnel and Carib00 River placer-bearing gravels were depositedin pre-late Wlsconsinan paleochannelsand late glacial to postglacialfluvial systems as high to intermediate-level terrace placers(Levson and Giles, 1993). Their possible lodegold sources are vein deposits in the Quesnel Lake, Spanish Mountain andCarib00 River areas. A number of other placer depositsare formed by, or have been reconcentrated in, ])ostglacial streams as Holocene, low-levelterrace placers and colluvial andalluvial fan deposits.

prospecting was done, but no gold recovery is recorded. (Levson and Giles,1993). Glacial and postglacial reconcen- Tertiaxy gravels from the same channel also crop out at tration of the Miocene placer gold is generally not signifi- Gravel Creek where it is crossed by the 150 Mile House - cant in the Horsefly area. Exceptions are some of the Horsefly road. Herethe gravels lie between Miocene basalt gold-bearing tributaries of Beaver Creek along Beaver and a thinlayer of Eocenelacustrine sediments that rest on Creek valley where postglacial reworkingis evident. Triassic basementin Gravel Creek. The sedimentarysection is not fully exposed but is no more than 30 metres thick. HORSEFLY AREA PLACER DEPOSITS Also, some Tertiarygravels are poorly exposedto the west (MIOCENE CHANNELS) of China Cabin Creek. Thegreater extent of the gravels is The villageof Horsefly (or Horse-fly) wasthe centre of indicated by the widespread distribution of white quartz a small placer mining community througb the heightof the cobblesin gravels and overburden throughout that area. TheCariboo gold rush into the early 1900s. It was known as thickness of the gravels in the southern channel appears to Harpers Camp from 1859 through to 1921 when. the ntame increase toward the north. This suggests that a small river was oftically changed to Horsefly. The discovery of gold on or large stream flowed north downBeaver Creek, and the Horsefly Riverin the spring of 1859 is creditcd to Peter possibly joined the larger Miocene channel. Dunlevey. He and a gang of men were led th~:up river and Pleistocene glaciation has since cut through to the shown wherethere was gold by two natives. Thesite of the Mesozoic bedrock and extensively scoured the Tertiary initial placer mining is immediately outside town, to the section. Variablethickness of till and glaciofluvialdeposits east, and was knownas the Ward's Horsefly mine.In Iecent have lefi behind a cover that ranges from a thin veneer a years, Horsefly has supported smalla community basedon metre or less in thickness,to sectionsup to 100 metres thick. forestry, ranching and recreation.The Horsefly River :is an The glacial deposits have roughly the same stratigraphy as important salmon stream and placer staking is no longer that described in the Cariboo placer district to the north permitted. However the surrounding regions near Antoine

Bulletin 97 91 Brirish Columbia

Modern W Tertiary H~nefiyRiverHorsefly River E Valley Miocene

. Bedrock-Tertiary Sediments Metre3

Flgure 8-10. Sketch map from Lay (1932) of probable coursesof Tertiary channels in the Horsefly amand diagrammaticcross-sections through the Tertiaryand modern channels atWard's Horsefly workings.

92 Geological SUN^ Branch Minisffy of Employment and Invesfmenf

Lake, Beaver Valley and Black Creek remainin the placer Miocene channel as there is no gold in the Quaternary reserve. gravels immediately adjacentto the mine.

Ward’s Horsefly (Harpers Camp), Miocene Shaft; MINFILE 093Af014 MINFILJ? 093Af015 Immediately adjacent to Ward‘s hydraulic operation, Initial work at the site by J.T. Ward, as well as the R.N. Campbell stakedat least twelve placer claims in 1894- Horsefly Gold Mining Company and International Dredg- 97, extending southwest through Harper’s Lake,and e!;tab- ing Company, was in Holocene reconcentrated placerat the lished the Miocene Gravel Mining Company. In 1898-99, margin ofthe Miocene channel.This ground is said to have Campbell sank a shaft, collared 300 metres southwe:rt of been very rich.Later workers have reportedthat it was the Ward’s pit. This shaft cut 84 metres of quartz gavels and quartz gravels that held the rich paystreaks. Holland (1950) then bottomed in 15 metresof shale (no doubt the Ewene that a total 15 216 ounces of gold were recovered. reports of lacustrine sediments). From the bottom of theshaft, 21 45- However, earlier authors estimated production worth $500 metre drift was driven westward into the gravels. Also a 000 to $1 250 000 during the life of the mine (Galloway, 76-metre decline was driven to the west from the shaft 1919; p. K137), resulting in a calculated production of bottom, dropping38 metres along its lengthat -39”. sirnilar 29,000 to 59,000 ounces of gold, assuming an average priceto the slope of the bedrock surface. Initially, Campbell for gold of $17.00 per ounce. The quantityis likely to have thoughtthe Miocene channel flowed westward through been greater as much of the gold was soldafter 1901 when Harper’s Lake into the head of Beaver Valley, but this was the price of gold had increasedto $20.67. not foundto be thecase. In 1900, he sanksecond a shafl. 600 Reports by the Resident Mining Engineer (Lay 1932, metres southwest of Ward’s pit. This is the locally well 1939) state that the Ward’s Horsefly operation worked the known ‘Miocene shaft’, andis located under the presenrday east edge of the Miocene channel. At this point the channelB.C. Telephone building at the junction of Waker’s Road is 150 metres deep and approximately 600 metres wide. Theand the main road in Horsefly village. This was a large stratigraphyconsists of a thin coverof Quaternary sediment three-compartment shaft that was sunk 167 metres,bot60m- over 7 to 24 metres of white quartz pebble conglomerate ing in the Eocene shales. A 152-metredrift was driven “in (Figure 8-10). The bottom 2to 7 metres of this wasthe ‘Blue the direction of the channel” and raises were cu: at 1:!2 to Gravel’ pay horizon. The “blue gravels” unconformably 152 metres to test the gravels. A run of slum from. the overlie shaly Eocene lacustrine sediments of unknown 152-metre raise flooded the workings and they were aban- thickness, dipping westat 30” to 35”. Thedip of the Eocene doned.Testingofthe~ravelswasnotextensivebut;itshowed rocks suggests that they have been tilted after deposition, goldinlessthan“payingquantities”(Galloway,1~~19).After another indication of Late Eocene, or younger, tectonic the flooding of the shaft, nofurther work has beem done on activity possibly related theto development of a graben.The the Miocene Gravel Mining Company ground. Eocene graben is now marked in part by the course ofthe Miocene and present day Horsefly Riverfluvial deposits. Hobson’s Horsefly; MINFILE 093Af015 The placer gold was initially recovered by surface placer mining methods. However, as mining progressed The earliest record ofactivity at the site of Iiobson pit deeper, the workingswere below the grade of the Horsefly is from 1887. By that time work hadalready been done on River and made normal mining methods difficult. By the reworked placer in the Horsefly River and mining was late 1880s drift mining was in progressat the site. Ward took progressing up the bank. Drift miningundemken was in the over the operation in 1891 and attempted some hydraulic cemented gravels andthe scope of operations expanded in work fora season. No significant workwas done for the next 1890 to include hydraulic mining. At that timethe site was five years, butin 1896 Ward undertook an ambitious devel- known as the McCallumclaims or the Discovery Company opment. He had two hydraulic elevators installed and a ground. major hydraulic operation began. Water was diverted from In 1892, J.B. Hobson, of the Cariboo Hydraulic Mining both Mussel andMoffat creeks to supply the monitors and Company and Bullion pit fame, took over the ground and elevators. A large pit, 100 metresor more across and up to began extensive development of water supply, drift and 18 metres deep was excavated. Gold recoveries werecon- hydraulic mining.A large-scaleoperation flourished sidered good and the operation continued throughto 1904. through to 1899. Over 2000 metres ofdrifts and cross;cuts At that time corporate problems resulted in closure of the webbed the cemented gravels at the close of 0pt:rations in mine. In 1915, a dredging venture was planned to rework 1899. The mined material was evidently processer: in a small the hydraulic tailings. However,poor Keystone-drilling re stamp mill. As well, several hectares of ground had been sults from work done bythe British Columbia Department sluiced off to the level of the cemented grav3:ls. Some ofMines in 1919killedtheventure. No significant work has additional hydraulic mining was carriedout frorn 190,8-12 been done at the site since then. by E.J. West.In 1930, George Kuchan tookovertheground. Due to the overlap of the modern andancient channels, He initially reworked the hydraulic tailings bul. made no there has been some recent reconcentration of placergold. advancements inthe old pit itself. Later, he worked ground However, the presence of gold is attributed strictly to the near Ratdam (Rat) Lakefor several years.

Bulkfin 97 93 production reported in Minister of Mines’ Annual Re- 300 metres upstream, smallera pit was developed and some ports for the Hobson pit is 7637 ouncesof gold for the years adits were drivento test the gravels. The hydraulic operation 1894 to 1898 and 1912. Asthe mine operated for a greater worked through to about 1935. Holland (1950) records a length of time this represents possibly only half, and prob- total of 62 ounces of gold produced fromthis creek. Since ably much less, of the tofal gold recovered. Grades in the the close ofthe hydraulic operaton, the Armesfamily drift mining werereported to be around $1.63 per tonne in worked the ground intermittently through 1985. No prcduc- the cemented gravels. Highestvalues were foundat the base tion has been recordedfor that time. In 1986, the property of the cemented gravels. The unconsolidated Miocene (pay) was purchased by Lyle Shunter who worked the ground 3 gravels returned $0.33 per metre and the overlying 30 to known as the ‘lower pit’. 50 metre section of unconsolidated glaciofluvial gravels The deposit is located within a narrowsteep-sided cleft carried minor gold,on average about$0.03 per metre’. inTriassicvolcanicrocks.Thegorgeisabout30metreswide The gravel deposits at the Hobson pit overlie from 15 at the falls and widens to about 300 metres at the lower pit to 23 metres of Eocene lacushine sedimentary “bedrock” and then narrows againto 30 metres at the top of the pit. The that rests unconfonnably on Triassic-Jurassic volcanic lowest sediments exposedare thinly layered muds, claysand rocks. In the pit the Miocene channelis about 3 metres thick fine sands of unknown thickness. Adrill hole 23.4 metres at the eastern edge butincreases to over 9 metres along the deep, collared in the middle ofthe pit floor, failed to reach western face where it is now covered by talus.The bottom bedrock. Unconfomably above the fine sediments are cross 1.3 to 3 metres is cemented by calcite to formnatural channeled, normally gradedfluvial gravels, 12 to 20 metres concrete. The rockis strong enough to support untimbered thick. Individual channels are up to 2.5 metres thick and 7 workings. At the base of the cemented gravels there is a metres wide. The placer gold occurs as runs in the coarse layer, a fewcentimetres thick, ofpartially cemented Eocene channel-lag gravels. A thin veneer of colluvium caps the sediments. Ripup clasts of the Eocene sedimentsare found section. in thebottom 30 centirnetres of the cemented gravels. The The gravels were interpreted to be part of the Miocene gravels at the Hobson pit are identicalto those of Ward‘spit. channelbytheearlyplacerminersbutLay(1931)statedthat They are white quartz pebble and cobble-richfluvial depos- the evidence for the gravels being part of the Miocene its. Heavy mineral concentrates contain abundant garnet, channel was inconclusive. Levson and Giles (1993) con- some kyanite and only alittle black sand, mainly pyroxene, sider the deposit to be a paleogulch placer. Certainly the magnetite and hornblende. abundance of whitequartz pebbles and cobbles the in fluvial Since G. Kuchan worked on the ground in the early gravels is not as great as that in the Hobson pit but, overall, 1930s no further work was done in the pit until 1987. In the quartz pebbles and cobbles are abundant. In addition, the summer of that year a consortium of companiesincluding tailings contain fragments of metamorphicrock with kyan- Laredo Mines Inc. attempted some undergrounddrift min- ite, and heavy mineral concentrates from the washplant ing in the cemented gravels, using an adapted continuous show abundant garnet, black sand andkyanite grains. The mining machine. Adecline was started in the west-pit face bench at the Black Creekplacer mine is interpreted here to and driven for approximately 30 metres before the mining be a higher bench of an upstream Miocene channelthat has machine failed.The enterprise was consideredto be devel- been reworked by the Recent Black Creek.The character of opment work andno attempt was madeto recover gold from this small benchis markedly different from the large lower the mined material. bench that surrounds Patenaude Lake about 100 metres below theelevation of the Black Creek workings. There the Black Creek;MINFILJi 093N016 gravels are mainly morainal deposits containing abundant Earliest reports of activity on Black Creek indicate metamorphic detritus and quartz cobbles. prospecting in the late 1890s by a Mr. Campbell (possibly The placer operation during 1987recovered ‘good‘ R.N. Campbell of the later Mioceneshaft). LaterPhilFraser quantities of gold fromthe fluvial gravels. Goldsize ranged worked on Black Creek andjoined with the Western Mines from flour to nuggets 10 millimetres across. The gold is Exploration Syndicate in 1918to do some Keystone drilling flattened, beaten and frequently coated in iron oxide,indi- on a bench about 3.2 kilometres up Black Creek from cating extensive transport. Horsefly River. The object was to test the bench for gold and determine ifit was part of the Miocene channel.Little gold Antoine Creek; MINFILE 093AfOI7 was recovered fromthe drilling and testing for the Miocene Placer work on Antoine Creek began in 1928. R.N. channel was inconclusive. It appears that no mining was Campbell worked the ground from Antoine Laketo the top done until 1930 when leases held byG. MacKeracher were of the gorge, approximately 1000 metres fromthe mouth of optioned by Rountree Mines Ltd. and managed by James the creek at Robert Lake. Initial work consisted of test Armes for further development. A large ground sluice was pitting andshaft sinking along the north bank ofthe valley, set up with the dumpat the falls, approximately 3000 metres followed by asmall amount of hydraulicking from 1929to upstream fromthe mouth of Black Creek, and extended 3001933. The section worked rested ona false bedrock of red metres upstream. A small hydraulic operation worked the clay/soil of undetermined depth. Above that were ‘blue ‘lower pit’ and washedgravels through the sluice. Another gravels’ of variable thickness, similar in character to those

94 Geological Survey Branch Miitisfry of Employment am1 Inveslmenr of the Miocene channelat Horsefly. Glacialdrift of variable QUESNEL RIVERDEPOSITS thickness caps the pay gravels. The gravels were not rich; the bottom metre of the ‘blue gravels’ reportedly carried Bullion Pit, Including DancingBill Gulch coarse flake gold with values up to $0.65 per metre (Lay, (187?-1884) and China Pit (1884-1894); 1931, 1933). Holland (1950) repom that a total of 189 MINFILE 093Al025 ounces of gold were recovered. The Bullion pit (Photo 8-2)is on the south side of the Lay (1932) shows the gravels at Antoine Creek to be Quesnel River, about 8 kilometres downstream from Likely. the downstream extension of the Miocene channel seen in It was the largest hydraulic mine in the Cariboo region and Horsefly. The projected Miocene channel swings west fromoneofthelargestintheworld.Thepitmeasures1600nietres Hobson’s pit, through Ratdam Lake and then Antoine Lakelong, 120 metres deep,75 metres across the bottom and 300 to discharge in BeaverValley and flow northwest fromthere metres across the top. Work began in the edy 1870s, (Figure 8-10), continued throughto the 1940s. and hassince bem intelrmit- tent. The mine was operated by Cariboo Hydrairlic Mining Other Placer Workings Company, J.B. Hobson (1894-1905), Guggenheim family interests (1906-1919). small operators (1920 to 1930 and 1943 to present), Quatsino Copper-Gold Mining Company China Cabin CreekThis small creek flows northward cf. p.89, B.C. Hydraulics Limited (1930-1931)andBlJllion out of China Cabin Lakeinto the head of Beaver Valley.The Placers Limited (1932-1942). Thegreatest amcunt ofpro- creek has been tested and there is evidence that a small duction was through the periods 1894to 1905 2nd 1934 to ground sluicing operatonwas undertaken immediately 1941. downstream from China Cabin Lake, lake The served as one Production of gold hasbeen substantial but Ibe qu:nntity of the sources of water for sluicing operations elsewhere is uncertain as much early production was not recorded and (Hobson’s pit?),as there is a largeditch leading away from the accuracyof later production recordsis suspect. Holland it. Gravels to the west of the lake contain abundant white (1950) quotes a total of 120 187 ounces (3740 kg) reported quartz clasts, suggesting that the Miocene channel, or its from the wholeof the southfork of the Quesnel River during erosion products, present in the area (authors, field are the period 1874to 1945. Levson andGiles (199.3) state that mapping). 150 500 ounces, were producedup to the end 01’the 1930s. Production fromall the Bullion pit operations eljtimated by Choate Creek(West Branch): This creek,also known the authors, based a varietyof sources and reportedquatities by the oldtimers as TeasdaleCreek, produced a small using average prices for that time, suggest that approxi- amount of gold. Here, coarse-boulder fluvioglacial outwashmately 171 000 ounces (5320 kg) of gold wen: recovered carries fine flakes and small nuggets, but no large-scale up to 1942 (Table 8-2). mining was done. A Mr. Teasdale lived off the land and Initial workatthesite which becametbeBullionpitwas augmented his supplies through purchases made with gold done by Chinese miners who followed up rich point-bar that he had mined (Milt Lonneberg, personal communica- deposits at the base of Dancing Bill Gulch. They worked a tion, 1987). small operation on the Quesnel River at the bottom(of the gulch that was expanded into a small hydraulic mine by Big Lake Creek The creek was prospected in the early1884. In 1894, a syndicate of Canadian Pacific Railway 1930s but did not yield any appreciable amount of gold. directors bought the Chinese operation and contracted J.B. However, as reported Lay (1933), the fineness of the gold Hobson to work the “China pit”as it had cometo be known. (980 fine) was the highest for any placer gold in the province The resulting ConsolidatedCariboo Hydraulic Mining to that date. The gold was recovered about 800 metres Company greatly expanded the water supply network, in- upstream from Beaver Creek. creased the number of men working and brought in better hydraulic equipment. Huge volumes of gravel were washed Starlike and Ikiplet Lakes: These lakes were thesite in the extensive sluice complex. In 1904, due to :n low of some prospecting in the late 1920s by J. Williams and bedrock grade of 1 to 2%, a sluice tunnel wascut from the associates. Quartz gravels were identified but couldnot be Quesnel River upto the middle of the pit. The3 by 3 metre specifically related to either the Moffat Creek drainage or tunnel was 500 metres long with a grade of 4.5% and a the main Miocene channel(Lay, 1932). The amount of gold 30-metre raise to the pit bottom (Sharpe, 1939; maps and recovered, if any,has not been recorded. plans, BCMEMPR Property File). Work continned through 1906 whenthe mine was bought by the Guggent eim family. Other placer deposits of the Horsefly River systemor Production continued but mining,financial and legal diffi- Miocene channel noted by Holland (1950) include Moffat culties were encountered andthe mine closed at the end of (Sucker),Mussel, ‘lisdale or Teasdale (currently locally 1907. called West ChoateCreek), Frasergold (Fraser) and Eureka At the close of operations a well-organimd town ex- creeks. Othercreeks said to have produced goldare ‘Captain isted at Bullionwhich included segregated quarters for Charlie’ (possiblypart of Antoine) and Parminter creeks. management, Caucasian, Chinese and Japanese min,ers; a

Bulletin 97 95 Brirish Coldin

Photo 8-2. Vlew of the Bullion pit, looking northwest. The photograph is taken from thewall; south the large excavation continuesto the east into the area of the China pit and Dancing Bill Gulch (right of photograph). fully equipped smithy; telephone/telegraph to the water have workedin the pit and nogreat recoveries of gold have supply points and the telegraph along the Fraser River, as been made. Interest in the mine is still evident and some well as a complex water supply networkcapable of supply- limitedmining activity still takes place in the pit ing large volumes of water (maps and plans, BCMEMPR sporadically. Property File). Forthe next 22 years, small operators inter- The gravels at the Bullion pit have the samepreglacial mittently attempted to work the mine, mainlyat the site of origin as those in the Cariboo deposits. The goldrecovered the old China pit. from the gravels was generally ‘coarse’ with many small In 1930 and 1931, the Quatsino Copper-Gold Mining nuggets worth $0.50 to $4.00 (roughly 1 to 7.5 grams in Company, through an affiliate, B.C. Hydraulics Limited, weight). Most of the gold was well worn and frequently and in 1932 Hireen Placers Limited worked the China pit coated with oxidized material. This goldis far travelled and by hydraulic methods and had modestrecoveries of gold. A is believed to be derived from distant sources in the Bark- disasterous failure of the working face destroyed the hydrau- erville Terrane. Some of the gold appears to be less worn lic operation, swept away more than a hundred metres of and possibly originates from nearby quartz veins such as sluice and plugged the top 40 metres of the sluice tunnel those in the basal Nicolaphyllite unit in the Spanish Moun- (Sharpe, 1939). tain area. In pan concentrates this gold is accompanied by In 1933, Bullion Placers Limited, under the direction abundant large, euhedral pyrite crystals and arsenopyrite of presidentR.F. Sharpe, tookover the mine, refurbished the grains. Some very large nuggets were evidently present as town and pit, renovating and expanding the water supply well. In 1988snipers salvaging old flume boards andsluice- system overthe next four years. A second pit was developedbox spillage from the tunnel spillwayto the Quesnel River in Drop Creek (called the South Forkpit) so that 24-hour recovered a flattened 300-gram (IO ounce) nugget that had mining could be done. This highly mechanized and well become wedged between some boards. organized operation worked continuously through to 1941 The lowest gravels in the section are fluvial and may and produced the present outline of the Bullion pit. Sharpe represent apre-Wisconsinfluvialenvironment.Above these died in 1942 and all work by Bullion Placers ceased. The are glaciofluvial and glacial gravels of the Early Wisconsin town of Bullion was abandoned, the water supply system stade. This section is 30 to 90 metres thick and contained fell into disrepair and subsequently no further hydraulic the richest gravels in the section. Unconformably above mining was done. Since the closure, only small operators these deposits is a layer of consolidated lodgement till,

96 Geological Survey Branch Minisrry of Employment and Invesrmenf "

TABLE 8-2 reported by Johnston (1923). The workings we~econfined pLA~ERGOLD P~~~~~.~N SINCE 1864 FROM largely to the creek bed or, in a few cases, were .on benches BULLION MmE, FROM up to 30 metresabove.According to Johnston,gravelsthe were probably postglacial but some of the benches might PRODUCTION RECORDS include glacial and interglacial accumulations. USIIMA1ED GRADE Morehead(SevenMile)Creek: MINFILE YARDS wLu\Rs mmGRADE wmmMAm EAR REPORTED oum OUNCES mn~v~~~ard OUNCES 093A/069Levson and Giles (1993) consider tht:Morehead *IW - wow 5291 5.9 Creek placersto be preglacial, large paleochannel deposits. 1893 1894 8 239 484 5.9 The setting is similar to the Bullion mine in :hat deeply 1895 210W 60% 3y17 zs.7 buried channeldeposits that predate glaciation rre ovmlain 1896 IMS3M I27445 7497 12.1 1897 MIM 133559 81m 16.5 thicksuccession a by of fluvial, lacustrine,glaciofluvial and 1m 105I41 6185 12.8 4.1 glacialdeposits. Some of the goldrecovered in the modern- 19 day drainage channels may be derived from erosion of the 5.8 older channels. Spanish Mountain Area: Workingsalong Spanish Creek, MINFILE 093N067, including Black :3ear Ihek 1% and theactive McKeownmine, are also rcgarded as 3 1w 5522 preglacial,large paleochannel deposits (Levsor*and IGiles, 7M7 1993). The gold-bearing gravels occupy the upper ptut of a I0482 6824 steep sided, elevated paleochannel eroded in bedrock. Gold close to bedrock in the lower gravels, a~uroxin~atelv60 to IN - - I . _. 1941 637m 5017 80 metres below surface, can be coarse. Nuggers up to 185 Tm*us: U14omO I2148 49149 grams (6 ounces)taken.beenhavelargencgeetsThe com-

Other Workings: Quesnel River (SouthFork) has numerous workings on benches and terraces below Likely including Lawless (Half Mile), Carberry Creek, Rose Gulch and in the vicinity of The Forks. 'lbo kilometres east of called the boulder clay bythe placer miners. The unconfor- Likely there was placer production at Poquette Creek. Cari- mity representsthe Olympia glacial interstade of the Middleboo River ('North Fork' of the Quesnel upRiver) to Crtrih Wisconsin. The lodgement till represents the base of the had workings, as did the tributaries at Kangxoo Creek, Upper Wisconsin Fraser glacial stade. The thickness of the Keithley/FourMile, Rollie (Duck) and Frank(Cloose) plac- lodgement tillis not specified but typicallyit is rarely more ers. Placers along the Quesnel Riverto the wesi andnorth- than 10 metres. Well stratified gravels form the upper30 to west of Quesnel Forks include the workings a! Maud and 50 metres of the section. The Pleistocene sectionis capped Birrell (Twenty Mile) creeks. In the lower Quesnel River by a veneerof Holocene debris (Sharpe, 1939, Fulton, 1984; region, near Quesnel, there was placer mining: at Sardine Clague, 1987; Levson and Giles, 1991). The valley fill in Flats, below the mouthof Deacon Creek andin 'he Quesnel the Bullion pit represents an ancientriver channel older than River Big Canyonarea. 100000yearsBP(Clague,1987)andisprohablyaprecursor Other placer workings noted by Holland (1950) or to the present Quesnel River. It appears that the Miocene Levson and Giles (1993) in the northern part Of map area and Pleistocene channels followedolder water courses. This include those on the Cottonwood River andon Sovereign, theory has been presented before by other workers in the Swift, Wingdam and Lightning creeks as well as 'Baker area and might be useful as a prospecting guideto find other Creek, a tributaryof the Fraser River, near Quesnel. buried channels. Clague(1987) has recently recognized and described a buried channeIthis of type on the Carib00 River. PLACER GOLD COMPOSITION AND LODE Cedar Creek- MINFILE0934141: This is a notable SOURCES placer creek as it is one of the rare new major discoveries The placer gold inthe Horsefly Riverarea contained in thatwasmadesincethe1860s.Thediscoveryin 1921 ofpay Miocene white quartz bearing channels doesnot appear to gravels at elevations around 300 metres above the present be locally derived from the volcanic arc basalric deposits. main valley bottoms resulted in recorded production 37of This is in contrast to some of the deposits in !he Quesnel 784 ounces (I 175 kg) ofgold (Holland, 1950). The deposits River drainange system which appear,in part a:: least, to be contained rich gravels. Over I6 OOO ounces (500 kg) was locally derived. The distinctive white quartz cl. arecon- recovered during 1921 to 1923 by using simplesluicing and tained in an argillaceousto micaceous matrix composed of rocking methods; in 1922 recoveries of 7 ounces gold per an abundance of clay-sized phyllosilicate minerals, mainly yard (166g/m3) of gravel over thicknesses of 2 metres are muscovite.Typica1 mineralogyofthe heavy minxalfraction

" Bullefin 97 97 TABLE 8-3 samples fromthe Quesnel River and to the south. Gold from COMPOSITIONS OF GOLD GRAINS RECOVERED lode sources in the Spanish Lake areais similar in compo- FROM PLACER CREEKSAND LODE GOLD sition or is slightly less fine, commonly from 750 to 790. SOURCES Compositions of placer gold in the map area reported by Holland (1950)range from 762 to 980fme. Compositions vary, the average fineness of more than 25 OOO ounces of gold recovered from the Bullion pit is 801, according to Holland, butthe fineness of individual samples varies from 762.5 to 822.5. The 980value from Big Lake Creek represents the highest gold content of any placer gold in the province (Holland, 1950). The probe work on individual grains shows distinct rimming andfracture-filling of placer grains by gold of very high fineness, for example, cores are around 775 fine but rims and healed fractures or veinlets are more than990 fine. Historic reported fineness represents an average sample composition. Individual deposits will vary in fineness depending on the ratio of core to rim inthe grains from various partsofthedepsit.Whethertherimswithhighgo1dcontent represent high-puritygold that has grown on the grains or is a product of leaching during transportationand maturation in the sites of deposition is a long-standing argument.The main element contained in the samplesin addition to gold is silver; other metals are present in very minor amounts. in pan concentrates includes abundant almandineand some Copper is generally present in amounts less than 200 ppm. spessaainegarnet,kyanite,andonlyminorblacksand(mag- Mercury rangesfrom a grain averageof 100 to 900 ppm in netite, amphibole, pyroxene,epidote and olivine). The gold the samples. Anomalous mercury content of up to 1.3% is itself is coarse to fine in size, well beaten, flattened and notedinsomeprobeanalysesoftheplacergrainsfromBlack partially coated with iron oxide. All these points indicate Creek. McTaggart and Knight (1993)also documented only that the gold has travelled a long distance. The abundance small concentrations of mercury, generallyless than OS%, of whitequartz pebbles in the Miocene gravels, the relative in the Carib00 andQuesnel River areas. A few anomalous sparseness of heavy minerals, black sand and notably py- placer creeks tothe north of Wells andBarkerville contain roxene, all indicate that the local basaltic volcanic terrain mercury in excess of1%. similar to the Black Creek placer. and mafic alkalicintrusions are not the source of the placer gold. Instead, the association of placer grains with garnet, SILT AND LITHOGEOCHEMICAL kyanite, rare brookitegrains and other metamorphic miner- STUDIES als indicates a source area in, or near, the high-grade metamorphic rocks of theBarkerville Terne. Alikely source for REGIONAL GEOCHEMICALSURVEYS the gold is the Middle Jurassic quartz veins in black pbyllite units near the Quesnellia-Barkerville terrane boundary. Stream sedimentand water geochemical surveysin the Quartz veins are abundant there in the strongly deformed central Quesnelbelt were conducted by the provincial Min- basal phyllites and a number of veins such as those at the ishy of Energy, Minesand Petroleum Resources in coopera- Frasergold deposit, are knowncany to gold. A source in the tionwith the federal government as part of the Triassic black phyllites is further supported by historical province-wide Regional Geochemical Survey (RGS) stud- evidence thatsome of the recovered goldwas still attached ies. These surveys in NTS map areas 93A, 93B, 93G and to rock grains ma& up ofquartz and black ‘slate’. Discus- 93H cover the Quesnel-Horsefly project and surrounding sions of lode golddeposits and their sources for placers that areas. Analyticalresults for 522sample sites in the map area are associated with ultramafic (ophiolitic) rocks emplaced and immediately adjoining regions, wereextracted from the along tectonic boundaries are presented byAsh et al., following RGS surveys: RGS 5, 1981, NTS 93A, RGS 6, (1996).Thecompositionsofsomeplacerandlodegoldfrom 1981, NTS 93B; RGS 13, 1986, NTS 93G and RGS 14, the region are discussed below. 1986, NTS 93H. These correspond to Geological Survey of Microprobe analyses of gold grains from a number of Canada publications OpenFile 776, Open File 777, Open placer and lode deposits are shown in Table 8-3. Composi- File 1214 and Open File 1215. tions of gold grains from 44 placer and 16lode sites in the The 522 sample sites in the project area, and some from Carib00 and Qnesnel River regionare reprted by McTag- the immediately adjacent region,are represented on Figures gart and Knight (1993). They document a dominant range 8-11 to 8-14. Stream sediment and wateranalytical data are of fineness,or parts per thousand gold, from 750 to 810 for summarized in Table 8-4. Symbols plotted on the figures

98 Geobgical Survey Branch Pb Cu Zn Ag

0 10 km

Y Figure 8-1 1. RGS stream sediments surveyfor Pb, Cu,Zn and Ag. Sample sites and symbolsfor >95 percentile values. c

I2L.W -

Figure 8-12. RGS stream sediment surveyfor As, Sb and Hg Figure 8-13. RGS stream sediment survey for U and Mo. c Co Ni

I - lW00'

Figure 8-14. RGS stream sediment survey forCo and Ni. Minisfryof Employment and Investment represent analytical results that are equal to or greater than of the volcanic belt and at least partially defines the 95 percentile values of the dataset. In this approach the intrusive centres. Copper in association with other 95 percentilevalues are plotted andlarger values are shown elements defines multi-element anomalie; in the meas symbols of increasing size. This method clearly identifies tasedimentary rocks ofunit 1. the largestvalues and emphasizes the highest5% analytical Zinc is present in black phyllites of unit1 and seem- values as 'anomalous', in this case about 30 sample sites. ingly is most abundant near the basal contact. Copper and zinc concentrations are, perhaps surpris- ingly, subdued with amounts rarelyhigher than thoseof the Silver is strongly anomalous throughout the map 95 percentile value. Individual elements appearto have the area. It might be the mosteffective element in iden- following attributes and distributions of anomalously high tifying mineralized regions as the anomal:y threshold values: represents the analytical detection limit (0.2 ppm). Every sample in whichsilver can be detected can be Lead is strongly anomalous in a number of sites from Spanish Lake northwest towards the Cariboo River considered to be anomalous. Silver is most abundant and further into the high-grade metamorphic rocks. in the metasedimentary rocksof unit1 and.,to alesser extent. the Cache Creek rocks.Silver is also concen- Anomalous copper withoutother associated anoma- tratedinthenorthempartofthevolcanicarc.Perhaps lous elements occurs in sites along the central axis significantly, it is strongly anomalousin one sample

TABLE 8-4 SUMMARY OF STREAM SEDIMENT DATA FOR TOTAL SAMPLE SET,IN PROJECT AREA AND

PROXIMITY: N=522 "

!ib W

LJF ION GCE AAS AAS AASAAS AAS AAS AAS AAS-H AASAAS AAS-F NADNC lu\s COWR

517 517 517 517517 517517 517 517 517 517 517517 517 517 512 517 340215517 517 517 484 514 21513 517 494 83 517 516 510 350 40 555333333 3 3333 3 8 3

0.19 63.9 7.68 68.5 34.4 4.1 35.7 11.4 0.141.7 8.1 910.5 223 2.8 73.4 1171 1.4 0.1 54 7.8 56 29 2 28 IO 0.1 555 5 1 2.2 59 2.5 0.4 1 0.02 50 8.1 56 22 I 28 IO 0.1 290 3 1 2.2 50 2 0.2 1 5.88 1090 3.5 2.1107456 234 81 172 20410 195 149 5.7 45.33390 7.7 44 0.3867.43 0.61 46.22 2259 7.05 28.54 6.54 0.16 1669.1314.04 6.68 0.76 154.71 2.55 0.89 2.35 2.W 1.0560.079 0.675 0.6% 1.71 0.799 0573 1.1811.833 1.73 3.87 0.339 2106 0.912 1245 1.699

Log Mean -0.959 1.7170.884 1.771 1.464 0.39 1.461 l.Ol2 4.939 2.783 0.707 0.08 0.322 1.759 0.374 4.336 0.05 &OM- 0.1 7.6552.1 590.1210.3 28.9 2.5 29.1 607.2 5.1 2.1 1.2 57.5 2.37 0.46 1.1 LogSslandardDcv. 0.4770.267 0.036 0.227 0.251 0.3940.278 0.197 0.186 0.326 0.363 0.23 0.157 0.247 0.238 0391 0.191 IagCaficicaVar. 4.477 0.155 0.04 0.1280.171 1.01 0.190.195 4.199 0.117 0.515 2.730.486 0.141 0.635 -1.167 3.889

Percentiles Minimum 4.02 40 5.4 4 6 4 cl cI 4.1 90 1 1 0.2 IO c.2

Daro source: Regional Geochcmicol Survcys (RGSJ 5,613.14. Open File Repom 776, m, 1214.1215 U y,F = wmivm in water; denotes less than detection lim't shown (not detected)

7- Bulletin 97 103 5 kilometres to the northwest of Horsefly village near in phyllitic rocks with known mesothermalgold veins. the postulated site of the western structural wall of Notable geochemical ‘hotspots’ identified are:the QR de- the Eocene graben. posit - an arsenic, antimony, mercury,cobalt anomaly; the trend of auriferous veins from Spanish Lake to Likely, Other elements with expected geochemical associa- marked by arsenic, silver and other element anomalies; the tions are arsenic-antimony-mercury, molybdenum-uranium trend of silver-bearingbase metal veins to the north-north- and cobalt-nickel. west of Spanish Lake, definedby bigb lead values; and the - Arsenic occurs in a number of anomalous sites, Eureka Peak area in whichthe presence of auriferous veins mainly in unit 1, and clearly in association with is indicated by multi-element anomalies. Anomalies that auriferous quartz vein systems. It is also strongly require additional investigation in order to relate them to anomalous inthe vicinity of the QRdeposit sources are the sites with high silver values, some with mercury, in the northwest part of the map area. Also the Antimony is commonly associated with arsenic in - sampling in Cache Creek rocks suggests a higher potential rocks of unit 1. It also occurs by itself or with silver and copper in unit 1 metasedimentary rocks but is for mineralization than might have been expected, particu- also present in Cache Creek rocks and inthe vicinity larly along the terrane-boundary fault zone with rocks of of the QR deposit. Quesnellia. More detailed examination of the data may undoubtedly reveal other significant geochemical andsta- * Mercury, with a few notable exceptions, is found tistical relationships and possiblyoutline areas of explora- mainly tothe north of the Quesnel River. It occurs in a variety of rock types and is probably associated tion interest. with faults. Mercury is presentin the QR deposit area Conclusions are that multi-element anomaliescan be and appears to be associatedwith silver-rich samples related to known mineralized showingsin most cases. Some farther tothe north. elements have a clear lithologic association, for example nickel with Crooked amphibolite. Some element distribu- * Molybdenum is concentrated in drainages emanating from the metasedimentary rocksof unit 1and the tions are a result of structural effects that juxtapose certain Cache Creek assemblage. Locallyit Occurs together lithologies and mineralizatiodalteration assemblages, for with arsenic and antimony, suchas in the QR deposit example, molybdenum with granites; uranium with meta- area. morphic rocks, and so forth. Part ofthe reason that thereis a better apparent geochemical endowmentin the sedimen- Uranium is largely confined tothe high-grade metamorphic rocks of the Barkerville Terrane and, to a tary rocks of unit 1 compared tothe volcanic rocksis simply lesser degree, faults or lithologic contacts in unit 1. that there is better dispersion in that region, both mecbanical and chemical. This is due to greater erosion and more - Cobalt, at fmt glance., appears to be concentrated efficient elemental transport inthe better established drain- throughout the rocks of unit 1, but closer examiua- age systems in the region of topograpbically greater relief. tion shows thatit is associated with zonescontaining anomalous arsenic, silver or other elements, com- This goes counter to anyapriorireasoning that suggests the monly in areas with mineralized quartz veins. areas underlain by volcanic and plutonic rocksare the more intensely mineralized and shouldhave the larger and more Nickel is concentratedalong both the east and west- evident geochemical anomalies. It is also perhaps signifi- em map boundaries,coincident with the major ter- cant that because of generally high values of pH in the rane-boundary fault zones and their contained volcanic belt, generally higher alkalinity than the in region serpentinized uluamafic rocks. underlain by metasedimentary rocks, someelements will be less mobile in the drainage systems and will be peferentially The associations of elements shown on Table8-4 (Fig- concentrated in oxidized rocks and overlying soils. Thus ures 8-11 to 8-14), as indicated by statistical correlation even low-level copper anomalies in sediments are very analysis, show strongcomlations between many pairs and significantin the volcanic belt.For example, the 70 percen- pupsof elements, notably high valuesof As-Sb and As- tile value for copper (40 ppm) clearly marks the regionsof Mo-Ag-Co. Perhaps more significantly, a number of li- the volcanic belt in which mostof the known copper occur- thologic associations and mappatterns are evident whenthe reuces are located. distribution of anomalous valuesis displayed on maps. The metasedimentaryrocks of unit1 generate the largest number and greatest concentrations of anomalous samples. Lithol- LJTHOGEOCHEMICAL SAMPLJNG ogy clearly controls the distribution ofuranium; structural Samples of mineralized, strongly altered or otherwise control of mercury is evident. Possibly both lithology and economically interesting rocks were submitted as grab or structure influence the distribution of nickel. Most other chip samples for analysis. The samples were analyzedfor anomalous concentrations can be related to discovered or implicit mineralized environments. Copper anomalies in gold, silver, copper,lead, zinc, cobalt, nickel, molybdenum, streams emanating fromareas underlain by volcanic rocks mercury, arsenic, antimony and barium. Resultsfor the 125 are a relatively subtle indicationof porphyry copper miner- samples analyzed, sample locations, descriptionsand other alization. Multielement anomalies effectivelyoutline areas sampling dataare presented in Appendices M and N. Most

104 Geological Survey Branch Ministry of Employment and Inve.rtment anomalous values can be attributed to obvious mineraliza- In addition, 49 samples representative of the various tion - usually veins or sulphide minerals contained in the rock types in the maparea were analyzed for platinum and rock. M~~~~,arsenic and antimony are effective ‘pa& palladium (and gold) as an orientation study to determine regional lithologic background values for tho!:e elements finder* that be to identifv,,hvdrothemallv ~~ ~I altered rocks. Antimony, even at low levels, is perhaps the (see Appendix 0).The samplecontaining 65 ppb platinum is from an unusual ‘appenite’ pyroxenite exposedin a cirque most sensitive indicator of mineralization. on Eureka Peak.

” Bulletin 97 105 British Columbia

106 Geological Survey Branch

- Ministry of Employment ana' Inveslment REFERENCES

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Campbell, R.B. (1961): Geology of Quesnel Lake, Sheet 93A de Rosen-Spence, A. (1985): Shoshonites and Associated Rocks (WestHalf), British Columbia;CeoIogicaISurveyof Canada, of Central British Columbia;in Geological Fieldwork 1984, Map 3-1961. B.C. Ministry of Energy, Mines and Petmleum Resources, CampbellR.B.(1963):GeologyofQuesnelLake,Sheet93A(East Paper 1985-1, pages 426-437. Half), British Columbia;Geological Survey of Canada, Map de Rosen-Spence, A. (1992): Lithchem Interpretive Method for 1-1963. CommonVo1canicSuites;inNewDevelopmentsinLithogeo- Campbell.R.B. (1973): Stnrcmral Cross-section and Tectonic chemisy, The University of British Columbia, Mineral De- Model of the Southeastern Canadian Cordillera: Cdan posits Research Unit,Short Course #8,45 pages. Journal of Em?h Sciences, Volume 10, pages 1607-1620. Ellam, R.M, Hawkeswonh, M.A., Menzies, M.A. and Rogers, Campbell, R.B. (1978): Quesnel Lake (93A)Maparea; Geologi- N.W. 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Ministry of Enegy, Mines and Petroleum Columbia; unpublished M.Sc. thesis,The University of Brit- Resoumes, AssessmentReport 12301.15 pages. ish Columbia, 137 pages. Carlyle, W.A. (1898): Reports,B.C. MinisfryofEnegy,Minesand Epstein, A.G., Epstein, J.B. and Hanis, L.D. (1977): Conodont PetmleumResources,MinisterofMinesAnnualReport1897, Color Alteration - An Index to Organic Metamorphism; pages 476.481,484. UnitedSfafesGeologicalSurvey,PmfessionalPaper995,27 pages. Carmichael, H. (1931): Carib00 and Quesnel Mining Divisions, Historical Summary; B.C. Ministry of Energy, Mines and Erdman, L.R. (1985): Chemistry of Neogene Basalu of British Pefmleum Resources, Bulletin l,pages52-54 (reprinted from Columbia and the Adjacent Pacific Ocean Floor: A Test of Bulletin 2, 1930). Tectonic Discrimination Diagrams; unpub1ishedM.S~. thesis, The University of Brifish Columbia, 294 pages. Carye,J.A.(1985):StructuralGeologyofpartoftheCrookedLake & QuesnelHighlands, British Columbia: unpublished Etheridge, M.A., Wall, V.J., Cox, S.F. and Vernon, R.H. (1984): MSc. thesis, The University of BrifishColumbia, 185 pages. High Fluid Pressure During Regional Metamorphism and Clague, JJ. (1987): A Placer Gold Exploration Target in the Deformation: Implications for Mass Transport and Deforma- tion Mechanisms;Journal of Geophysical Research, Volume Cariboo District, British Columbia; Gealogical Survey of CaMdn, Paper 87-1A, pages 177-180. 89,pages 434-4358. Coates J.A. (1960): Analcite Bearing Volcanic Rocksthe Ques- of Etheridge, M.A., Wall, V.J. and Vernon, R.H. (1983): The Role of ne1 River Group,Carib00 District, British Columbia; unpub- Fluid Phase During Regional Deformation and Metamor- lished B.Sc thesis, The University of Brifish Columbia, 56 phism; Journal of Metamorphic GeoIogy, Volume 1, pages pages. 205-226. CocK1el& WE. andWalker, J.F. (1932): Geology and Placer Eyles, N., Clark, B. and Clague, J.J. (1987): Coarse-grained Sedi- Deposits of the QuesnelForb Area, Carib00 District, British ment Flow Faciesin a Large SupraglacialLake; Sedjmentol- Columhia: in Summary Report 1932, Part A I, Geological ogy, Volume 34, pages 193-216. Survey of C&, pages 76-143. Eyles, N. and Kocsis,SF! (1988a): Placer Gold MininginPleisto- Coney, PJ., Jones, D.L. and Monger, JW.H. (1980): Cordilleran cene Sediments of the Cariboo District, British Columbia, Suspect Terranes; Name, Volume 288, pages 329-333. Canada 1858-1988; Geoscience Canada, Volume 15, pages 293-301. Cox. K.G., Bell, J.D. and Pankhurst (1979):The Interpretation of Igneous Rocks; Geoge Allen and Unwin Limifed, London, Eyles, N. and Kocsis, S.P. (3988b): Gold Placers in Pleistocene 450 pages. Glacial Deposits, Barkerville, British Columbia; Canadian Dawson,G.M.(1877):RepononExplorationinBritishColumbia; Insfifufeof Mining and Metallurgy, Bulletin, Volume 81, in Report ofProgress 1875-6, Geological Survey of Canaab, pages 71-79. pages 233-265. Eyles, N. and Kocsis, S.P. (1989): Sedimentological Controlson Dawson, G.M. (1879): Preliminary Report on the Physical and Gold Distribution in Pleistocene Placer Depositsof the Cari- Geological Features of the Southern Portion of theof Interior boo Mining District, British Columbia;in Geological Field- British Columbia; in Report of Progress 1877-8,Part B, work 1988, B.C. Ministry of Energy, Mines and Pefmleum Geological Survey of C&, 187 pages. Resources, Paper 1989-1, pages 377-385. Dawson, G.M. (1895): Summary Report of the Operations ofthe Ferri, F., Dudka, S. and Rees, C. (1992): Geology of the Uslika Geological Survey ofCanada for the year 1894;Geological Lake Area, Northern Quesnel Trough, B.C. (93C/3,4, 6): Survey of Cad,Summary Report 1984, pages A22-28. Grant, B. and Newell,J.M., Editors, in Geological Fieldwork

108 Geological Survey Branch Ministry of Employmentan‘! Investment

1991, B.C. Ministry of Energy, Mines and Petroleum Re- CmradianInstituteofMiningandMetallurgy,SpecialVt~lume sources, Paper 1992-1,pages 127-145. 46, in press. Fillipone, J.A. (1985): Structure and Metamorphismat the Inter- Gabrielse, H. (1991): Structural Styles; Chapter17 in Geology of monrane-OminecaBoundary,nearBossMonntain,East-cen- the Cordilleran Orogenin Canada, Gabrielse, H.,,and Yorath, tral British Columbia;unpublished M.Sc. thesis, The C.J., Editors, GeologicalSurveyof Canada, Geology ofcan- University of British Columbia, 156 pages. ada, Number 4, pages 571-675. Fillipone, J.A. and Ross,J.V. (1990): Deformation of the Western Gabrielse, H. and Yorath,CJ. (1991): Tectonic Synthesis; Chapter MarginoftheOminecaBeltNearCrookedLake,East-cenual 18 in Geology of the Cordilleran Orogen in Canada, British Columbia;Canadian Journal Earthof Sciences, Vol- Gabrielse, H. and Yorath, C.J., Editors, Geologicul Survey of ume 27, pages 414-425. Can&, Geology of Canada, Number4, pages 677-705. Fitton, J.G. and Upton, B.G.J., Editors (1987): Alkaline Igneous Galloway, J.D. (1919): North-eastern District (No. :!), Ho.rsefly Rocks; Geological Society Special Publication Number 30, Section; B.C. Ministry of Energy, Mines and Petroleum Re- Blackwell Scientific Publications, 568 pages. sources,MinisterofMinesAnnualReport1918,llagesI:136- Fletcher, C.J.N. (1972): Structure and Metamorphism of the Pen- K142. fold Creek Area, near Quesnel Lake, Central British Colum- Galloway, J.D. (1919): North-eastern District (No. 2). Quesnel bia; unpublished Ph.D. thesis, The University of British Mineral District, Horsefly Section;B.C. Ministry ofEnergy, Columbia. Vancouver, B.C. Mines and Petroleum Resources, Minister of Mines Annual Floyd, P.A. and Winchester, J.A. (1975): Magmavpe andTectonic Report 1918, pages K136-Kl43. Discrimination Using Immobile Elements;Earth and Plane- Galloway, J.D. (1921): North-eastern District (No. 2), Quesnel tary Science Letters, Volume 27, pages 211-218. Mineral District, Horsefly Section;B.C. Ministry of Energy, Fulton, RJ. (1984): Quaternary Glaciation, Canadian Cordillera; Mines and Petmleum Resources, Minister of Mines Annual in Quaternary Stratigraphy, Fulton,R.J., Editor, Geologicul Report 1920,pagesN100-N105. Survey of Cam&, Paper pages 84-10, 3948. Galloway, J.D. (1922): Northeastern District (No. 2). Quesnel Fox, P.E. (1975): Alkaline Rocks and Related Mineral Depositsof Mineral District;B.C. Ministry of Energy, Mine::and Petm- theQuesnelTrough,BritishColumbia,(Ahstract)Cordilleran leum Resources, Minister of Mines Annual Report 1921, Section; Geological Associarion of Cd,Symposium on pages G114, G116. Inhusive Rocks and Related Mineralization of the Canadian Gamett, J.A. Geology and Mineral Occurrmces of the Cordillera, Program and Abstracts,page 12. (1978): Southern Hogem Batholith;B.C. Ministry of Enevy, Mines Fox, P.E. (1989): Alkaline Copper-GoldPorphyries: Schizo- and Petroleum Resources, Bulletin 70,75 pages. phrenic Cousins of Real Porphyty Coppers;in Copper-Gold Porphyry Workshop, Mineral Deposits Division,Geological Garwin, S.L. (1987): Structure and Metamorphism thein Niagara Association of Cd,Workshop Notes, Vancouver,2 pages. Peak Area, Western Carib00 Mountains, British Columbia, unpublished MSc. thesis, The University of British Colum- Fox, P.E. (1991): A Model for Alkaline Copper-Gold Porphyry bia, 177 pages. Deposits; Abstract,Geological Association of Cd,1991 Annual Meeting,Program with Abstracts, pageA39. Getsinger, J.S. (1985): Geologyof the Three Lalies Moun- tainiMount Stevenson Area, Quesnel Highland, BritishCo- Fox, RE., Cameron, US. and Hoffman,SJ. (1986): Geology and lumbia: unpublished Ph.D. thesis, The Universiy of 6ritish SoilGeochemistryoftheQuesnelRiverGoldDeposiSBritish Columbia, 239 pages. Columbia; in GEOEXPO ‘86,Association of Exploration Geochem’sts, Meeting proceedings.Vancouver. pages61-71. Ghent, E.D., Stout, M.Z and Ferri,F. (1989): Chloritoid-Parago- nite-Pyrophyllite and StilpnornelaneBearing I

.” .” Bulletin 97 IO9 British Columbia ~ ~~ ~ ~~

Hawkeswonh,C.J. and Norry, MJ., Editors, (1983): Continental Keppie,J.D.(1988):TectonothermalEvolutionoftheWestAfrican Basalts and Mantle Xenoliths;ShivaP~lishing~mifed, 272 Orogens and Circum-Atlantic Terrane Linkages;Geoscience pages. Canada, Volume 15, No. 3, pages 212-214. Harland, W.B., Armstrong, R.L., Cox, A.V., Cmig, L.E., Smith, Koo, J. (1968): Geology and Mineralization in theLorraine Prop A.G. and Smith,D.G. (1990): A Geological TimeScale 1989; erty Area,Omineca Mining Division, B.C.; unpublished Cambridge University Press, 279 pages. MA. thesis, The University of British Columbia, 107 pages. Hodgson,CJ.,Bailes,RJ.andVemza,R.S.(1976):Cariboo-Bell; Lang, J.R., Stanley, C.R. andThompson, J.F.G.H. (1993): ASub- in Porphyry Depositsof the Canadian cordillera, Sutherland division of Alkalic Porphyry Cu-Au Deposits into Silica- Brown, A., Editor, Canadian Institute of Miningand Metal- Satorated and Silica-Undersatuarated Subtypes;in Porphyry lurgy, Special Volume 15, pages 388-396. Copper-Gold Systemsof British Columbia,The Universityof British Columbia, Mineral Deposit Research Unit, Annual Holland, S.S. (1964): Landforms of British Columbia, A Physiog- Technical Report- Year 2, pages 3.1-3-14. raphic Outline;B.C. MinistryofEnergy, MinesandPetroleum Resources, Bulletin 48,138 pages. Lay, D. (1928): North-eastem Mineral Survey District (No. 2). Horsefly Section; B.C. Ministry of Energy, Mines and Petro- Holland, S.S. (1950): Placer Gold Production of British Columbia; leum Resources, Minister of Mines Annual Report 1927, B.C. Ministry of Energy. Mines and Petroleum Resources, pagesC181-Cl82. Bulletin 28 (reprinted in 1980). 89 pages. Lay, D. (1931): North-eastem Mineral Survey District (No. 2). Hoschek,G.(1969):TheStabilityofStauroliteandChloritoidand Horsefly Section;B.C. Ministry of Energy, Mines undPetm- Their Significance in Metamorphism of Pelitic Rocks, Con- leum Resources, Minister of Mines Annual Report 1930, tributions to Mineraloa and Petrology, Volume 22, pages pagesA176-AI78. 208-232. Lay, D. (1932): North-eastem Mineral Survey District (No. 2), Hoy, T. and Andrew, K. (1988): Preliminary Geology and Geo- Horsefly Section; B. C. Ministry of Energy, Mines and Petro- chemistry ofthe Elise Formation, Rossland Group,between leum Resources, Minister of Mines Annual Report 1931, NelsonandYmir,South~ternBritishColumbia;inGeologi- pagesA96-AI01. cal Fieldwork 1987, E.C. Ministry of Energy, Mines and Petroleum Resources, Paper 1988-1,pages 19-30., Lay, D. (1933): North-eastem Mineral Survey District (No. 2), Horsefly Section:B.C. Minimy of Energy, Mines and Petro- Iddings,J.P.(1895):Absaroldte-Shoshonite-Ban~teSeries;Jour- leum Resources, Minister of Mines Annual Report 1932, nal of Geology, Volume 3, pages 935-959. pagesA117-AI18. Itvine, T.N. and Baragar, W.R. (1971): A Guideto the Chemical Lay, D. (1934): North-eastern Mineral Survey District (No. 2), Classification of the Common Volcanic Rocks: Canadian Horsefly Section;B.C. Minisfry of Energy, MinesandPetro- Jouml of Eurth Sciences, Volume 8, pages 523-5448, leum Resources, Minister of Mines Annual Report 1933, page Jakes, P. and White, AJ.R. (1972): Major and Trace Element A145. Abundances in VolcanicRocks Orogenic Areas; Geologi- of Lay, D. (1939): North-eastern District, Summary and Placer-gold cal Society of America Bulletin. Volume 83, pages 29-40. Deposits, Horsefly Area;B.C. Ministry of Energy, Mines and Johnston, W.A. (1923): Placer Mining inCedar Creek Area,B.C.; PetroleumResources,MinisterofMinesAnnualReport1938, in Summary Report, 1922, Part A, Geological Survey of Part C, pages CI-C46. Canuai?, pages 68-81. Le Bas, M.J., Le Maiue, R.W., Streckeisen, A. and Zanenin, B. Johnston, W.A. and Uglow, W.L. (1926): Placer and Vein Gold (1986): A Chemical Classification of Volcanic Rocks Based Deposits of Barkerville, Cariboo District, British Columbia; on the Total Alkali-Silica Diagram; Journal of Petrology, GeologicalSurvey of Cd,Memoir 149,246 pages. Volume 27, Part 3, pages 745-750. Johnston, W.A. and Uglow,W.L. (1933): Placer Gold Deposits of Lefebure, D.V. (1976): Geology of the Nicola Group in theFair- Barkerville, Carib00 District, British Columbia;in Summary weather Hills, British Columbia; unpublished MSc. thesis, Report 1932, Part Al, Geological Survey of Canada, pages Queen’s Universip, 179 pages. 1-75. Levson. V.M. and Giles, T.R. (1991): Stratigraphy and Geologic Jones,D.L.,Howell,D.G.,Coney,PJ.andMonger,J.W.H.(1983): Setting of Gold Placers in the Carib00 Mining District; in Recognition, Chawter, and AnalysisofTectonosaatigraphic Geological Fieldwork 1990,B.C. Ministry of Energy,Mines Terranes in Western North America; in Accretion Tectonics andPetroleum Resources, Paper 1991-1, pages331-344. in Circum-PacifG Regions: Proceedingsof the OjiInter- the Levson, V.M. and Giles, T.R. (1993): Geology of Tertiary and national Seminar on Accretion Tectonics, HashimotoM., and Quaternary Gold-Bearing Placers in the Carib00 Region, Uyeda, S., Terra Scientific Publishing Company, Editors, British Columbia (93A.B, H); Grant,B. and Newell,J.M., Tokyo, pages 21-35. G, Editors, B.C. Ministry of Energy, Mines and Petroleum Re- J0plin.G.A. (1968): TheShosbonite Association: AReview;Jour- sources, Bulletin 89,202 pages. nal of the Geological Society of Australia, Volume 15, Levson, V.M., Giles,T.R., Bobrowsky, P.T. and Matysek, P.F. Number 2, pages 275-294. (1990): Geology of Placer Deposits in the Cariboo Mining Karlsson, H.R. and Clayton, R.N. (1991): Analcime Phenocrysts District, British Columbia; Implicationsfor Exploration; in in Igneous Rocks:Primary or Secondary ?;American Miner- Geological Fieldwork 1989,B.C. Minisfry ofEnergy, Mines alogisr, Volume 76, pages 189-199. andPerroleum Resources, Paper 1990-1, pages 519-529.

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Lewis. ED.(1987): PolyphaseDefomationand Metamorphism in British Columbia;Mineralium Deposita, Volume :!SA, pages the Western Cariboo Mountains near Ogden Peak, British S115-124. Columbia; unpublishedMSc. thesis, The University of Brit- Miyashiro, A. (1975): Volcanic Rock Series and Tectonic Setting; ish Columbin, 146 pages. Annual Review of Earth and Planetary Sciences, Volume 3, Logan, 1.M and Koyanagi, V.M. (1994): Geology and Mineral pages 251-269. DepositsoftheGaloreCreekArea(104Gn,4);B,C,Ministry Monger, J.W.H. (1977): Upper Paleozoic Rocks of the Westem of Enem, Mines and Permleum Resources, Bulletin 92,96 Canadian Cordilleraand Their Bearing on Cordilleran Evo- pages. lution; Canadian Journal of Eorth Sciences, kolume 14, Lu, Jun (1989): Geology of the Cantin Creek Area, Quesnel River pages 1832-1859. (93B116); in Geological Fieldwork 1988, B.C. Ministry of Monger, I.W.H. (1993): Canadian Cordilleran Tectonics: From Eneqy, MinesandPetmleumResources,Paper1989-1,pages Geosynclines to Crustal Collage;Canadian Journal of Earth 173-181. Sciences, Volume 30, pages 209-231. LUM, E.C. (1911): Quesnel Mining Division; B.C. Ministry of Monger, J.W.H., Price, R.A. and Tempelman-Kluit, D.J. (1982): Energy. Mines and Petmleum Resources, Minister of Mines Tectonic Accretion and the Origin of Two Major Metamor- Annual Report1912, page K53. phic and Plutonic Welts in the Canadian Cordillera;Geology, Volume 10, pages 70-75. Mathews, W.H. (Compiler) (1986): Physiography of the Canadian Cordillera; Geofogical Survey of Camfa,Map 1701A, scale Monger,J.W.H.,Souther,J.G. andGabrielse,ft (1972): Evolution 1:5oooooo. oftheCanadianCordil1era;APlateTectonicModelAmer;kan Journal of Science, Volume 272, pages 577-602. Mathews, W.H. (1989): Neogene ChilcotinBasalu in South-central British Columbia: Geology,Ages, and GeomorphicHis- Monger, J.W.H.,Wheeler, J.O., Tipper, H.W., Gabrielse, H., tory; Canadian Journal of Earth Sciences, Volume 26, pages Hanns,T., Struik,L.C.,Campbell,R.B.,Dcdds,CJ.,Gehrels, 969-982. G.E. and O'Brien, J. (1991): Part B. Cordilleran X>rrane:;;in Upper Devonian to Middle Jurassic Assemblages, Chapter8 McInnes, B.I.A. and Cameron, E.M. (1994): Carbonated, Alkaline of Geology of the Cordilleran Orogen in Canada, Gabridse, Hybridizing Melts from aSub-arc Environment: Mantle H. and Yorath, C.I., Editors, Geological Survey of Cam&, Wedge Samples from the Tabar-Lihir-Tanga-Feni Arc, Papua Geology of Canada, Number4, pages 281-327. New Guinea; Earth and Planetary Science Leffers,Volume 122, pages 125-141. Montgomery, I.R. (1985): Structural Relations of the Southern Quesnel Lake Gneiss, Isoceles Mountain Area, Central Elrit- McMullii, D.W.A. (1990): Thennobarometry of Pelitic Rwks ish Columbia; unpublished MSc. thesis, The Un,iversip Deposits Research Unit(MDRU), in preparation. per-Gold Systems of British Columbia, The University of Meade,H.D.(1977):Pe(rologyandMetalOccurrencesoftheTakla British Columbia. Mineral Deposit Research Uni:, Annual Group and Hogem and Germansen Batholiths,Noah Central Technical Report - Year 3. British Columbia, unpublished Ph.D. thesis, University of Mortensen, J.K.. Montgomery, J.R. and Fillipone,J. (1987): U-Pb Westem Ontario, 354 pages. Zircon, Monaziteand Sphene Agesfor Granitic Ortllognesiss Melling,D.R.andWatkinson,D.H.(1988):AlterationofFragmen- of the Barkerville Terrane, East-central British Columtia; tal Basaltic Rocks: The Quesnel River Gold Deposit, Central CanndianJoumalofEarthSciences,Volume~,pa;:es12lil- British Columbia; in Geological Fieldwork1987, B.C. Min- 1266. isrry of Energy, Mines and Petmlewn Resources, Paper Mortimer, N. (1986): Late Triassic, Arc-related, PotassicIgneous 1988-1,pages 335-347. Rocks in the North American Cordillera; Geology, Volume Melling, D.R.,Watkinson, D.H., Fox, P.E. and Cameron R.S. 14, pages 1035-1078. (1990): Carbonahtion and Propylitic Alteration of Frag- Mortimer, N. (1987): The Nicola Group: Late Triassicmd Early mental BasalticRocks. Quesnel River Gold Deposit. Central Jurassic Subduction-relatedVolcanism in British Columbia;

" Bulletin 97 1'11 British Columbia

Canadian Joumalofhrth Sciences, Volume 24, pages 2521- Panteleyev, A. (1987): Quesnel Gold Belt - Alkalic Volcanic Ter- 2536. rane between Horsefly and QuesnelLakes (93N6); in Geo- Morton, R.L. (1976): Alkalic Volcanism andCopper Deposits of logical Fieldwork 1986,B.C. Ministry of Energy, Mines and Petroleum Resources, Paper 1987-1, pages 125-133. the Horsefly Area, Central British Columbia; unpublished Ph.D. thesis, Carleton Univerxity, 196 pages. Panteleyev,A.(1988):QuesnelMineralBelt-TheCentralVolcanic Axis between Horsefly and Quesnel (93N5E, 6W); MuUenEIX(1983): ~OnT02/P205:AMinorElementDiscn~- Lakes in Geological Fieldwork 1987,B.C. Ministry of Enegy, Mines nant for Basaltic Rocks of Oceanic Environments and Its and Petroleum Resources, Paper 1988-1, pages 131-137. Implications for Petrogenesis; &Rh and Planeta?y Sciences Lefters, Volume 6, pages 53-62. Panteleyev, A. and Hancock K. D. (1 989a): Quesnel Mineral Belt: Summary of the Geology of the Beaver Creek - Horsefly Muller, D. and Groves, D.I. (1993): Direct and Indirect Associa- RiverMapArea;inGeologicalFieldwork1988,B.C.Ministry tions Between Potassic Igneous Rocks,Shosohonite and of Energy, Mines and Petroleum Resources, Paper 1989-1, Gold-Copper Deposits; Ore Geology Rewiews; Volume 8, pages 159-166. pages 383-406. Panteleyev, A. andHancock, K.D. (1989b): Geology ofthe Beaver Mutschler, EE, Larson, EE and Bruce, R. M. (1987): Laramide Creek - Horsefly River Map Area, NTS 93N5, 6; B.C. and Younger Magmatism inColorado - New Petrologic and Ministry of Energy. Mines and Petroleum Resources, Open Tectonic Variations on Old Themes; Colorado School of File 1989-14, 150OOO map. Mines, Quarterly, Volume 82, Number 4, pages 147. Paterson, LA. (1977): The Geology and Evolution of the Pinchi Mutschler,F.E. andMooney,T.C. (1993): Precious Metal Deposits Fault Zoneat Pinchi Lake, Central British Columbia;Cow- Related to Alkaline Igneous Rocks - hovisional Classifica- dianJoumalofhnhSciences,Volume 14,pages 1324-1342. tion, GradeTomage Data, and Exploration Frontiers;Kirk- ham, R.V., Sinclair, W.D., Thorpe, R.1. andDuke, I.M., Pearce, J.A. (1982): Trace Element Charactenstics of Lavas from Editors, in Mineral Deposit Madeling, Geological Associa- DesmctivePlateBoundaries;inAndesite;OrogenicAndesite and Related Rocks, Thorpe, R.S., Editor, John Wley and tion of Cd,Special Paper40, pages 479-520. Sons, pages 525-548. Nelson, J.L., Bellefontaine, K.A., Green, K. and Mach, M. (199 I): Regional Geological Mappingnear the Mount Milli- Pearce, J.A. (1983): Role of the Subcontinental Lithosphere in Magma Genesisat Active Continental Margins; in Continen- gan Copper-Gold Deposit (93W16, 93N/I); in Geological Basalts and Mantle Xenoliths, Hawkeworth, CJ. and Fieldwork 1990, B.C. Ministry Energy, Mines and Petro- tal of Norry, M.J., Editors, Shiva Publishing Limited, pages 230- leum Resources, Paper 1991-1, pages 89-110. 249. Nelson, J.L., Bellefontaine, K.A.,Rees, C. and MacLean, M. Pearce, J.A. and Cann, (1973): Tectonic Settingof Basic Volcanic (1992): Regional Geological Mapping in the Nation Lakes Area (93N/ZE, Grant, B. and Newell, J.M., Editors, in RocksDeterminedUsingTraceEiementAnalyses;Eanhand 7E); Planetory Science Letters, Volume 19, pages 290-300. Geological Fieldwork 1991, B.C. Ministry ofEneqy, Mines andPetroleum Resources, Paper 1992-1, pages 103-118. Peccerillo, A. and Taylor, S.R. (1976): Geochemistry of Eocene Calk-alkaline Volcanic Rocks from the Kastamonu Area, Nelson, J.L., BeUefontaine, K.A., Mach,M.E. and Mountjoy, Northern Turkey;Contributions Mineralogy Petrology, Vol- KJ.(1993):GeologyoftheKlawliLake,KwanikaCreekand ume 58, pages 63-81. Discovery~eekMapAreas,NorthernQuesnelTerrane,Brit- ish Columbia; Grant, B. and Newell, J.M., Editors, in Geo- Pilcher, S.H and McDougall,JJ. (1976): Characteristics of Some logical Fieldwork 1992,B.C. Ministry of Enew, Mines and Canadian Cordilleran Porphyry Prospects;in Porphyry Cop- PetroleumResources, Paper 1993-1, pages 87-107. per Deposits of the Canadian Cordillera, Sutherland Brown, A., Editor, Canadian Institute of Mining ond Metallurgy, Nelson, J.L. and Bellefontaine, K.A. (1995): The Geology and Special Volume 15, pages 79-82, with Table 1. Mineral Deposits of North-Central Quesnellia; Teueron Lake to Discovery Creek, Cenrral British Columbia; Grant, Poulton, T.P. and Tipper, H.W. (1991): Aalenian Ammonites and B. and Newell,J.M., Editors, B. C. Ministry of Energy, Mines Strata of Western Canada; Geological Survey of Cad, andPetmleum Resources, Bulletin, inpres. Bulletin 411,71 pages. Nelson, J.L. and Mihalynuk, M.(1993): Cache Creek Ocean: Preto, V.A. (1972): Geology ofCopper Mountain; B.C. Ministry ClosureorEnciosure?;Geology,Volume21,Number2,pages of Eneqy, Mines and Petroleum Resources, Bulletin 59.87 173-176. pages. Ni~on,G.T.,Archibald.DA.andHeaman.L.M.(1993):~Ar-~~ArPreto, V.A. (1977): The Nicola Group: Mesozoic Volcanism Re- and U-Pb Geochronometryof the Polaris Alaskan-type Com- lated to the Rifting in Southern BritishColumbia; in Volcanic plex, British Columbia;Precise Timing of Quesnellia - North Regimes in Canada, Baragar, W.R.A., Coleman, L.C. and America Interaction; Geological Associatio~inerological Hall, J.M., Editors, Geological Association of Cam&, Spe- Association of Cu&, Program and Abstracts, Edmonton cia1 Paper 16, pages 39-57. 1993, page A-76. Preto, V.A. (1979): Geology ofthe Nicola Group betweenMemtt and Princeton; B.C. Ministry of Energy,Mines andPerroleurn Oldow, J.S., Bally, A.W., Lallemant, H.G.A. and Leeman, W.P. Resources, Bulletin 69.90 pages. (1989): Phanerozoic Evolutionof the North American Cor- dillera; United States and Canada; in The Geology ofNorth Preto, V.A., Osatenko, M.J., McMillan, WJ. and Anstrong, R.L. America - An Overview,The Geological Society of America, (1979): Isotopic Dates and Strontium Isotopic Ratios for The Geology of North America, Volume A,pages 139-232. Plutonic and Volcanic Rocks in the Quesnel Trough and

112 Geological Survey Branch Minisfry of Employmenfand In==

Nicola Belt, Southcentral British Columbia;Canadian Jour- Columbia; in Structure of the Southern Canadian Cordillera, MI of Eanh Sciences, Volume 16, pages 1658-1672. Wheeler. 1.0.. Editor, Geological Association OJ'Camah, Price,R.A., Monger, J.W. H. andMuller, J.E. (1981): Cordilleran Special Paper6, pages 123-135.

Cross-section ~ Calgary to Victoria; Geological Association Schink, A.E.(1974): Geology of the Shko Lake Slock, near of Canada, Field Guide to Geology and Mineral Deposits, Quesnel Lake, British Columbia, unpublishedB.:Sc. thesis, Annual Meeting,Calgary. The University of Brifish Columbia, 64 pages. Radloff, J.K.(1989): Origin and Obduction of the Ophiolitic Schiarriza, P. andPreto, V.A. (1987): Geology of the Adms Redfern Complex on the Omineca - Intermontane Belt Plateau -Clearwater- Vavenby Area;B.C. Minisfry ofEnergy. Boundary, Western Carib00 Mountains, British Columbia; Mines and Perroleurn Resources, Paper 1987-2.88 pager:. unpublished M.Sc. thesis, The University of British Colum- bia, 179 pages. Sharpe, R.F. (1939): The Bullion Hydraulic Mine; The Miizer, Volume 12, pages 37-40. Read, P.B. and Okulitch,A.V. (1977): The Triassic Unconformity of Southcentral British Columbia; Canadian Journal of Shervais, J.W. (1982): Ti-V Plots and the Petrogenesisof Modern Earth Sciences, Volume 14, pages 606-638. and Ophiolitic Lavas; Earfh and Planetary Science Letters, Volume59, pages 101-118. Read, P.B., Woodsworth. G.J., Greenwood, H.J., Ghent, E.D. and Evenchick, C.A. (1991): Metamorphic Mapof the Canadian Sillitoe, R.H. (1989): Gold Deposits in the Western Pacific Island Cordillera, Geological Survey of Canada, Map 1714A. Arcs - The Magmatic Connection;in The Geology of Ciold 1:2 OOO OOO. Deposits: The Perspective in 1988, Economic Geology, Rees,C.J.(1981):WesternMarginoftheOminecaBeltatQuesnel Monograph 6, pages 274-292. Lake, British Columbia; in Current Research, Part A, Geo- Sketchley, D.A., Rebagliati, C.M. and Debug, C. (19%): Gsol- logical Survey of Canada, Paper Sl-lA, pages 223-226. ogy. Alteration and Zoning Patterns of the Mt Milligan Rees, CJ. (1987): The Intermontane - Omineca Belt Boundary in Copper-Gold Deposits: Schrwter, T.G., Editor, in Porphyry the Quesnel Lake Area,Eastcentral British Columbia: Tec- Deposits of the Northern Cordillera, Canadian Iwrirub? of tonic Implications Based on Geology, Structure and Paleo- Mining andMetallurgy, Special Volume 46, pages 650-665. magnetism; unpublished Ph.D. thesis, Cariefon University, Sloman, L.E. (1989): Triassic Shoshonites from the I)olomi.Ses, 421 pages. Northern Italy: Alkaline An: Rocks in a Strike-slip Setting; Rickwood, P.C. (1989): Boundary Lines Wlthin Petrologic Dia- Journal of Geophysical Research, Volume 94, Nomber B4, grams Which Use Oxides of Major and Minor Elements; pages 46554666. Lirhos, Volume 22, pages 247-263. Solomon, M. (1990): Subduction, Arc Reversal, and the. Origin of Robert, E and Taylor,B.E. (1989): Structure and Mineralizationat Porphyry Copper-Gold Deposits in Island Arcs; Geology, the Mosquito Creek Gold Mine Carib00 District, B.C.; in Volume 18, pages 630-633. Structural Environment and Gold in the Canadian Cordillera, Souther, J.G. (1977): the CordilleranSection.GealogicalAssociarionafCanada,Short VolcanismandTectonicEnvimnmentsin Course Number 14,Vancouver, pages 25-57. Canadian Cordillera- a Second hk;in Volcanic: Regimes in Canada, Baragar, W.R.A., Coleman L.C. and I3all. J.M., Robertsou, W.F. (1903): Carib00 District; B.C. Minisfryof Enegy, Editors, GeoiogicalAssociarion of Canada, Specia. Papa 16, Mims and Pefraleum Resaurcps, Minister of Mines Annual pages 3-24. Report 1902. pages 69-81. Spence A. (1985): Shoshonites and Associated Rocks 3f Central Rock, N.M. (1987): The Need for Standardization of Normalized British Columbia; in Geological Fieldwork 1984,B.C. blin- Multi-elementDiagramsinGeochemistry;AComment;Geo- isfVofEnqy,MinesandPermleumResources, Paper 15'8.5- chemical Joumal. Volume 21,pages 75-84. 1, pages 426-442. Roddick, J.A., Wheeler, 1.0.. Gabrielse, H. and Souther, J.G. Steiger, R.H. and lager,E. (1977): Subcommision Gfochronol- (1%7): Age and Nature of the CanadianPart of the Circum- on ogy: Conventionon the Use of Decay Constantsin Geo- and Pacific Orogenic Belt;Zcfonaphysicss, Volume4, pages 319- Cosmochronology; Earth and Planerary Sclenre Lerters, 337. Volume 36, pages 359-362. Ross J.V., Fillipone, J.A., Montgomery, J.R., Elsby, D.C. and Bloodgood. MA. (1985): Geometry of a ConvergentZone, Stephenson, W. (1897): Keithley Division; B.C. Ministry of En- Central British Columbia, Canada;Zcfonophysics, Volume ergy, Mines and Perroleurn Resources, Minister of Mines 119, pages 285-297. Annual Report 1896, page 515. Ross, J.V., Ganvin, S.L. and Lewis, ED. (1989): Geology of the Stem, R.J., Bloomer, S.H., Lin Ping-Nan, Ito. E. and Mom:;, 1. Quesnel Lake Region, Central British Columbia: Geometry (1988): Shosohonitic Magmas in Nascent Arcs: New Evi- and Implications; in Proceedings, 7th International Confer- dence from Submarine Volcanoes in the Northern Marialaas; ence on Basement Tectonics, D. Reidel, Dordecht, Nether- Geology, Volume 16, Number 5, pages 426-430. lands, pages 1-23. Struik,L.C. (1981): SnowshoeFormation, Centra1Briti:rhColwm- Saleken, L.W. and Simpson,R.G. (1984): Carib-Quesnel Gold bia; in Current Research, PartB, Geological Suwwy of C!an- Belt; A Geological Overview; Western Miner, April 1984, ada, Paper 81-A, pages 213-216. pages 15-20. Struik. L.C. (1983): Bedrock Geology of Spanish Lake (93Nll) Schau, M.F. (1970): Stratigraphy and Structure of the Type Area and partsof Adjoining Map Areas, Central British Columbia; of the Upper Triassic Nicola Group in South-central British Geological Survey of Canada, Open File Map 920.

" Bulletin 97 113 British Columbia

Shuik,L.C.(1984a):GeologyofQuesnelLakeandpartofMitchell lipper, H.W. (1959): Quesnel, British Columbia;Geological Sur- Lake, British Columbia;Geological Survey of C&, Open vey of Canada. Map 12-1959. File Map 962. Tipper, H.W. (1978): Northeastern Part of Quesnel (93B) Map Struik,L.C.(1984b):SaatigraphyofQuesnelTemeNwsDragon area, British Columbia,in Current Research,Part A, Geologi- Lake, QuesnelMaparea, Central British Columbia;in Cur- cal Survey of Canada, Paper 78-1, pages 67-68. rent Research, Part A,Geological Survey of Canada. Paper Tipper,H.W.,Woodsworth,G.J.andGabrielse,H.(1981):Tectonic WlA, pages 113-116. Assemblage Map of the Canadian Cordillera and Adjacent Stluik, L.C. (1985a): %st and Strike-slip Faults BoundingTec- Parts of the United States of America; Geological Survey of tono-stratigraphicTerranes, Central British Columbia, in Canada, Map 1505A, 1:2 000 000. FieldGuidestoGeologyandMineralDepositsintheSouthern Wheeler, J.O., Brookfield, A.J., Gabrielse, H., Monger, J.W.H., Canadian Cordillera, Tempelman-Kluit, DJ., Editor, Cordil- Tipper, H.W. and Woodsworth, G.J. (1991): Terrane Map of leran Section, GeologicalAssociatwn ofAmerica,Colorado, the Canadian Cordillera;Geological Survey of Canada,Map pages 141-148. 1713A, 1:2ooOooO. Srmik,L.C.(1985b):Pre-CretaceousTerranesandtheirThhmstand Wheeler, J.O. and Gabrielse,H. (1972): The CordilleranSwctural Strike-slip Coutacts,Prince George (East Half) and McBride Province; Geological Association of Canada, Special Paper (West Half) Map Areas, British Columbia; in Current Re 11, pages 1-81. search,PartA,GeologicalSurveyofCaM&,Paper1985-1A, pages 267-272. Wheeler, LO. and McFeeIy, P. (1991): Tectonic Assemblage Map of the Canadian Cordillera and AdjacentParts of the United Struik, L.C. (1986): Imbricated Terranes theof Carib00 Gold Belt States of America; Geological Survey of Canada, Map withCorrelationsandImplicatiousforTectonicsinSoutheast- 1712A, 1:2000000. em British Columbia; CadianJournal of Earth Sciences, Volume 23, pages 1047-1051. Winkler, HJ.E (1979): Petrogenesis ofMetamorphicRocks; Fifth Edition, Springer Veriag, New York, N.Y., 348 pages. Struik,L.C.(1987):TheAncientWestemNorthAmericanMargin: An Alpine Rift Model for the Eastsenual Canadian Cordil- Wilson, W.M.H. (1977a): Middle Eocene Freshwater Fishes from lera; Geological Survey of Canadn, Paper 87-15, 19 pages. British Columbia; Royal Ontario Museum, Life Sciences Contributions,Number 113, pages 1-61. Shuik, L.C. (1988a): Regmd Imbrication within Quesnel Ter- rane, Central British Columbia, as Suggested by Conodont Wilson, W.M.H. (1977b): Paleoecology of Lacustrine Vmes at Ages;CaMdi~JoumalofEanhSciences,Volume25.pages Horsefly, British Columbia;Canadian Journal of Earfh Sci- 1608-1617. ences, Volume 14, pages 953-962. Srmik, LC. (1988b): Srmchlral Geology of the Carib00 Gold Wilson, W.M.H. (1984): Year Classes and Sexual Dimorphismin Mining District, East-central British Columbia; Geological the Eocene Catostomid FishAmywn Aggregatum; Journal Survey of CaMdn, Memoir 421, 100 pages. Includes maps of Vertebrate Paleontology, Volume 3 (3), pages 137-142. 1635A (93W14).1636A (93W3). 1637A (93N13) and Woodsworth, G.J., Anderson, R.G. and Armstrong, R.L. (1991): 1638A (8N14). Plutonic Regimes; Chapter 15,in Geology ofthe Cordilleran Sutherland Brown,A. (1963): Geology of the Carib00 River Area, Orogen in Canada, Gabrielse, H. and Yorath, C.J., Editors, British Columbia;B.C. Ministry of Energy, Mines and Petro- Geological Association of Canah, Geology of Canada,Vol- lewn Resources, Bulletin 47,60 pages. ume 4, pages 491-531. Sutherland Brown,A. (1976): Morphology and Classification; in Yoder, H.S.and Tilley, C.E.'(1962): Origin of Basalt Magmas;An Porphyry Deposits of the Canadian Cordillera. Sutherland Experimental Study of Natural and Synthetic Rock Systems; Brown, A., Editor, Canadinn Institute of Mining and Meral- Journal of Petrology, Volume 3, pages 342-532. lurgy, Special Volume 15, pages44-51. Zanettin, B. (1984): Proposed New Chemical Classification of Thomton,CP.and~~,O.F.(1960):ChemistryofIgneousRocks. Volcanic Rocks; Episodes, Volume 7, pages 19-20. I. Differentiation Index; American Journal of Science, Vol- Zen, E-An and Thompson,A.B. (1974): Low-grade Metamorphic ume 258, pages 664-684. Mineral Equilibrium Relations;Earth and Planetary Science Letters, Annual Reviews, Volume2, pages 179-212.

114 Geological Survey Branch Ministry of Employment am! Invesrmenr APPENDICES

” Bulletin 97 115 116 Geological Survey Branch Ministry of Employment and Invesment

APPENDIX A COMPOSITION OF PYROXENE FROM UNIT 2 ~- Analysis of zoning in individual pyroxene grains(this study, M. Mihalynuk, analyst) and map-unit average values from Bailev. (1978). AII valuesin weight perclii. ' 87AP 31/6-96;mapunit 2b -alkali basalt: Determinations = 8 SiOz TiOz Nt4 FeO MnO MgO CaO NazO KzO' crZ03 pyroxene graincore 50.0 0.51 3.61 7.91 0.27 14.40 22.2 0.33 0.M' 0.02 centre 50.5 0.56 4.03 8.09 0.29 14.30 22.0 0.38 0.N' 0.03 rim 50.4 0.61 4.34 8.16 0.26 14.10 22.2 0.35 0.0G 0.04 average 50.6 0.56 3.99 8.05 0.27 14.30 22.1 0.35 0.M' 0.03 86AP 4/6-18,analcite pyroxene basalt- mapunit 2e: Determinations = 5. pyroxene graincore 51.2 0.41 51.2 graincore pyroxene 3.61 6.94 0.20 15.00 22.8 0.30 0.K' 0.12 centre 50.4 0.46 50.4 centre 4.20 7.27 0.19 14.50 22.7 0.30 0.W 0.15 rim 40.0 0.58 5.24 8.38 0.26 13.50 22.3 0.36 0.fX 0.02 average 50.2 0.48 50.2 average 4.35 7.43 0.22 14.30 22.6 0.32 0.M' 0.06 87AP 5/8-14,mapunit 4 - analcite olivine basalt: Determinations = 9 pyroxene graincore 49.8 0.66 5.34 7.39 0.19 14.40 22.1 0.46 0.K: 0.08 centre 49.7 0.61 49.7 centre 5.45 7.52 0.20 14.30 22.2 0.49 0.W 0.07 rim 0.6850.0 5.02 7.51 0.22 14.48 22.2 0.41 0.K 0.03 average 49.8 0.65 49.8 average 5.27 7.47 0.20 14.40 22.1 0.45 0.N 0.06 Mapunit average values(Bailey, 1WS) Alkali Olivine bslt, unit2a, N=19 0.7150.3 4.39 7.73 0.11 13.90 21.9 0.53 0.02 0.14 Alkali bslt unit 2b, N=2 51.6 0.44 4.49 6.86 0.15 13.50 22.9 0.13 0.08 0.28 Analcite alkali bslt unit2e, N=2 0.6852.7 5.44 6.77 0.24 13.00 22.5 0.35 0.07 0.33

" Bulletin 97 117 Bri2isk Columbia

118 Geologicul Survey Brunch Ministry of Employment ana Inveslment "

APPENDIX B MICROFOSSIL (CONODONT) DATAFORTHE QUESNELMAP AREA __- Field No. MapLatitude NTS Longitude MapUnit Longitude Loeation Identifieation As CAI* GSC No. " 86AP-25/3-7bCl 1 52'-29'-22" 93N6 west~rntip of worm tubes Phanerozoic C-117601 121"-25"34" Honefly Pcnninsula (indctcrminate)

86AP-26/680-Q 1 52"-27"54" 93N6 2.5 km S of castern tip ichthyoliths late Paleozoic- C-117602 121"-22'-25" of Horscfly Penninsula, shell material Mcsozoic on S shore of Quesnel L.

1 52--28"33" 93N6 barren 121*-2049"

86AP-2515-88-01 1 52"-28'4?" 93N6 on S shore Qucsnel L, 121"-20'41" 2.5km SE of eastern tip Honcfly Penninsula

2f 52429'4" 93N6 E endof Caribou Island barren 121"-21'-9" 2a 52*-29'-56" 93N6 N. shore Qucsnel L, at barren 1219'27'45" Mitchell Bay

86AP-29/1-102-C7 52°-30"31"2a 93N12 W shorn Querncl L, bamn 121°-30'-43" 2 km N Hazcllinc PI L87C4-8 2f 52'-53"39" 93B/16 Cantin Creek area foraminiferid Silurian to recent C-117642 1220-9'-28" (Ammonodisas?) probably Upper Triassic DB87-W4 52'410'66" 93B/9 S. shore Quesnel R ichthyoliths Phanerozoic C-117643 1229-oo"30" pmbably Upper Triassic

87AP-12/3-31 I 52'-24"47" 93N5 Antoinc Ck., 1.6 km ichthyoliths UpperTriassic, 2.5-3.5 C-117644 121=34'49" downsmm from conodont ma: Epigoandolella cf.. probably lower Anmint L. E. abneptir Huckriede Noria" nmiform elements, Ncogondolclla sp. 88AP-08/05-C1 1 52°-25'-18" 93M5 Beaver Valley: 8 km NE Concdontr, ichthyolilhs: Mid.-U. Triassic 4.5 c-154102 121"413"50" of Gco~cLk (cliff at Conodont taxa: Anisian-Camian Gillespie Ranch) Ollism me Ncopndolella ? sp. in cliffcarbonate

88AP-1013-CZ 1 52'-22"40" 93M6 5.5 km NE Lemon L cO"~0"ls: U. Triassic 3.5.4 c-154105 121"-12'49" approx. 1 km N of Mctapolyg~thussp. Late Camian smroad ex gr. nodusus (Hayashi) 88AP-11/4-C3 52O-Ze-36" 1 93N5 1 km SSE Dorrey L [Halobia site] probably Triassic C-IS4106 121°41'746" on watcdine mad iehlhyolilhr 88AP-1114-C4 1 52'-26"36" 93N5 1 km SSE Domy L ichthyolilhs Phanerozoic C-154107 121'417'46" on waterline mad 88AP-l1/4ES 1 52'-26"36"93A/5 1 km SSE Domy L barren c-154108 121"47'416" on watcrline road 88AP-WbC6 1 52*-2@43" 93MS 1 km SSE DoncyL Cancdontr, ichlhyoliths U. Triassic; 4.5 c-154109 121"48"4' on waterlinc mad Conodont ma:Metaplygnathus Lato Camian

SAP-126 2a 52"-28"29" 93Mffi Horsefly river mad, barren 121"-25"00" 0.9h SE of Mitchell Bay 85AP-126a 2a 52"-28"29" 93Mffi Harrefly river mad, 121"-25"00" 0.9km SE of Mitchell Bay SAP-126b 2a 52*-28"29" 93" Horscfly river mad. barren 121"-25"00" 0.9km SE of Mitchcll

Bulletin 97 119 I20 Geological Survey Branch APPENDIX C EUREKA PEAK- QUESNEL LAKE MICROFOSSIL (CONODONT)DATA __

Field No. LatitudeMap NTS Map CAI' GSC No. Unit longitude Identifieation Loeslion AW " 86MB-154?2 I 529-27'41" 93An bamn C-117629 120~45'46"

86MB-36-08 1 52"-26'-33" 93An bamn 0117630 120~48"s

86MB-17-01 I 52"2i"14" 93An barren C117631 120"50"22'

86MB-17M 1 52"21"19' 93An barrcn 0117632 120'-50"11"

86MB-2609 1 52"16"2' 93An barren 0117633 120'-39"53'

86MB-27-01 1 52*-20"55" 93An banen 0117634 120'-39'4*

86MB-28-02 1 52"2049" 93An barrcn C-117635 120'"42'

86MB-33-13 1 52'-19"56' 93An banen C-117636 120%42"1'

87MB-0102 1 52*-33"17" 93Nlf Conodonts: M.Triasric :j 0117645 121"16"12' Nsogondolslla ex gr. Late Anisian mnsvicm (Morhcr& Clark) early Ladinian Nsogondolellarp. el. N. alpina (Kozuur & Mostlw 1982) ramifom elements

87MBM-W 1 52'-33"54"93.4'11 SpnishLkares bamn 121°-?0-51'

87MB-W-05 1 52"40'-9" 93N9 HobSon Lkm barren C-117647 120"3'-30'

87MB-07-06 1 52'46" 93NllSpishLkm barren 0117648 121*-20"35"

87MB-1602 1 52'-32"50- 93Nll Spanish MI".. E. ConodonCt: Middle Masif 5-5.5 C-117649 121~-21"1" Chiowlla timomris Early Anisian (Nagami 1968) ramifom C~SIIKIIS

87MB-19M I 52435'-32'93.4'11 SpnishLkma bamn C-117650 121"26-12"

87MB-19-06 1 52--34r43" 93Nll SpanirhLk- barren c-154101 121~-21"15"

87MB-2741 1 5Z044'-42' 93.4'11 SpnirhLkm banen mnwminatd 121'-19-57"

87MB-FX 1 52"-16'"32" 93An EurelwPeakm bnmn

Bulletin 97 I21 British Columbia

122 Geological Survey Branch Ministry of Employment and Iz:=enf

APPENDIX D MICROFOSSILS (PALYNOMORPHS)FROM THE QUESNELMAP AREA "

mnglornemle " Identifications:

Bulletin 97 123 British Columbia

124 Geological Survey Branch APPENDIX E MICROFOSSIL DATAFROM THEQUESNELMAPAREA

QUESNEL PROJECT COLLECTIONS

FkMNumbrr Msp hlltudr NTS hllon IdenlUksIIm &e GSChHon Unit LoDgUude Map N"ElbW .",-"

SAP-82 3 52-27-43 93N6 C-118687 121-27-26 85AF-96B 3 52-28-37 93N6 c-118685 121-29-19

85AP-96c 3 52-28-25 93N6 C-118686 121-29-19

86AP-20l3-6l 2cZfl 52-26-20 93N6E 0.4 km SE of Shiko L GI17626 121-28-40

86AP-3015-114 2f 52-25-46 93N6E 2.5 km SE ShikoL C-117627 121-27-23

DE8743 2f 52-38-41 93M12 5kmNNEMorrheadL C-117609 12147-52 on Morehead Ck 28 m above base ofsection

DL38744 21 52-38-41 93N12 5 km NNE Momhead L Noriq probably upperNorian GI17610 121-47-52 on Morehead Ck I m above DB 87-43 DB87-45 2f 52-38-41 93N12 5 km NN€ Morehead L No- probably upperNorim C-117621 121-47-52 onMonheadCk meas DB 87-44 DB87-46 2f 52-38-41 93N12 5 km NNX Morehead L Age not determined GI17637 121-47-52 mMoreheadCk 12 m above base, 16 m below DE 87-43 DE8748 2f 52-38-41 93Ml2 5 kmNNE Morehead L GI17638 121-4742 onMoreheadCk 2 m above DB87-46

21' SL.,!,-,2 YMIO Upper inassic 121-27-24 (APPENDIX E Continued)

87AP-17/5-39 2f 52-2547 93N6 2.3 km SE Shiko L benthonic bivalve apsrrnblagc,same unit (7) ay GI17627 Upper Triassic C-117639 121-27-24

87AP-2512-76 1 52-23-31 93N5 2.3 km E Roben L flattened ammonite7 C-117641 121-3342

88AP-llI4-35-FI IA 52-26-37 93N5 Hobbio sp., psibly a flattened ammonite, a bivalve Probably IOWRNO~~~or upper Camian c-154111 1214746 and 8 brachiopod.

88AP-12/1O-F2 IA 52-27-24 93N5 wnfains HOlObiia sp. PmbablylowR.NorianM.uppcrCamian GI54110 12148-33

88AP-I8/3OF3 2A 52-20-30 93N6 wnlaim Hoiobio sp. Pmbably lower Norian or upper Camian GI54112 121-12-26

88AP-22/7-71-€4 LA 52-19-28 93N6 1.2 km NE Patenaude L a bivalve (Hulabin?) Pmbably lower Norian orupper Camian C-154113 121.09-56

OB88601 2AnD 524042 931\/12 4.5kmENESlidcMm bivalves and brachiopods UpperlHassic C-154I14 1214844

DB88602 2AnD 52-4042 93Nl2 4.5 kmENE SlideMm bivalves and brachiopods Upper Triarsic CI54lI5 1214844

88AP-1114C3 IA 52-26-3693W05 Halobia sp. Triassic, Camian c-154106 1214746

Data Sources: Geological SUNVofCanada fossil idmtificafion C-118685.118686,118687-Jl5-1986-HWT,J3-l992-HWT,JI-1993-HWT,H.W.Tlppr,C-l1867-J9-1986-TPP,T.P.Poulta~;C-117626,117627-Jll-1987-En',E.T.Tolcr C-117609,117610,117621-1R4-1987-ETT,E.T.Tmcr;C-l1637,11638-~4-1987-E7T,E.T.Tmrr;C-I54110,154111,154112,154113,154114,154115,H.W.Tipp~ ~wrineneommunicatiom, H.W. Tipper, l986,l987,1988,1992, I993 Field Number wlleelor sample code: DE. D.O. Bailey: AP .A. Panteleyev sample

GEOLOGICAL SURVEY of CANADA REPORTS on FOSSILS COLLECTED In the QUFSNEL LAKE AREAby VARIOUS GEOLOGISTS

Map GSC hSliLW Idrntiflestions Age CoUectorIReport U nit NumberUnit

U pper CamianUpper RBC:(1978) DGB

2 91862 grrybasalt0SkmNofthe CIH (1974) E end ofGavin L Tr48-1974-ETT 2 93215(a) MorehcadCk3.2kmNof Prorocarda (?) SP., Castatorin sp. aft C. sunonemis(Clapp Shimer) U. Triassic,prob. Norim DGB J4-1976-TPP MoreheadL LioIrigonia (?) SP., aft L OYI?O Goldfuss, Costatoria(?) or Myophorigonio (?) sp Seplocardia (?) sp.. undetermined brachiopods

2 91858 (?) Morehead Ck2.4 km from NOriall CJH(1974),HWT- 91859 (?) Quesnel L Triassio Upper Tr18-1974-En' (APPENDIXE Continued)

2 40027 2 RBYl%I);ffiB; 42432 'Tr ll-6ol61-ETT 3 93215@) 3 ffiB 14,113-1976-TPP 93960 13-1992XWT 93961

3 93214 3 DGB 14-1976-TPP J2-1976HF 13-199292HWT

3 93216 3 DOE; 14-1976-TPP

3 93217 Lowerlurauic

3 or2f 19578, MorehadCkplaoerminepit RBC (1959); WEC; Do% 19580, 1.6 km upemfmm Qucrncl R J3-1992HWT 40019 J1-1993XWT 19579.

40018 Mmheadck phaminepit RBc(1959); DGB 3.6 km upmram fromQursncl R J3-1992-W not in PlaeC GI17287NshoreMmhcdL HWT(1986) Jl-19931iwT

C-118685 SofHa2eltinePoint,QuesnelL GI17286 lat5292S'3~,iong121910'42"

6117285 SOrH~HimePoim,QunndL HWT(1986); J3-1992-HWT GI18685 lat52°2S'24",lmg 12170'47" Jl-1993HwT 42434 mad cut, N bank Querncl R LowerPiimbachien; RBC; DG%J18-1976-H€ 937524.35kmdownrmam fromLikely Freboldi Zone 14-19694iF; HWT(1986) J3-1992-HWT; Jl-1993-HWT

90769Likely. Tyee WcLeese L)mad Upper Pliensbaehim, RBC, J1-1974-HF junetion,90mtothenotih Kunae Zone 13-1992HWT

40030 I20 m NW of outlet ofBeaveridgsL Aaltnim RBC, Poulton andTipper (1991); JI-1974-HF J3-1992-HWT

91755Opheim L.mad out at SE end Aalcnim PoultonandTipper(l99I) C-149638 I28 Geological Survey Branch Ministry of Employment omfInvestment

APPENDIX F PETROCHEMISTRY SAMPLE DATA FOR THE QUESNEL MAP AREA "

LAB Ell3I.D LA"IVDEWNGn'l.DE NTS UNIT N UM BER NUMBERNUMBER 0 , ,, 0 , VI MAP LOCATIONIAREANUMBERDESCRIPTION ROCK

~ 38434 Ap88-24/02-71 52-25-38 121-7-27 93AI 6 35339 Cll-9 52-57-56 122-16-21 93W16 35340 CI1-ll 52.58- 2 122-1619 938116 ."32641 . APS21M46 52-22-38 121-18-26 93AI 6 32642 AP862m.4-92 52-29.46 121-2b50 93AI 6 32643 AP86-28/07-98 52-29-57 121-2743 93AI 6 31607 AP85.09/01-72 52-2S.u 121-24-21 93AI 6 31@9 AP85-m-115 52-29.23 121-23-30 93AI 6 37026 AP88d"19 52-2b 3 12142.15 93AI 5 38435 AP88-2W3-70 52-19-W 121-1os76 93AI6 35553 DB8741 52-28.55 121-3963 93AI 5 2A 35560 DB87-20 52-29-59 121-27-58 93AI 6 2.4 35569 DB87-21 52-29.22 121-41-29 93AI 5 2.4 35573 DB87-25 52-32-15 1214541 93AI12 2A 35574 0887-26 52-3749 121-37-37 93AI12 35575 DB87-27 52-3749 121-37-37 93AI12 35580 DB87.33 5243.4 121-5b14 93AI12 35582 DB87-35 52-40-31 1214641 93AI12 35586 DB87-40 524141 121-53-37 93AI12 35325 01-10 52-53-17 122- 8-37 93B116 28 Cantin Ck. Gcrimi & 35326 C4-12B 52.5?-12 122- 8-31 938116 2B Cantin Ck.Gcrimi 0; 35330 c7-3 52-53-33 122-10-5 93Bl16 28 CantinckGcrimia(1kmn 32052 AeBMw10-29 52-25.54 121.2144 93AI 6 2B HmkccrL(3kmNE) 32053 Ae8610iU8.44 52-25-37 121-22-59 93AI6 2B HmkecrL(1kmN) 32054 AP8blM3-51 52.25.25 121-20-14 93AI6 28 UWL(IkmW) 31597 APgS-lll-35A 52-2647 121-2840 93AI 6 2B shiko L 31611 AP85-223.123 52-28-39 121-22-31 93AI 6 2B mmny peni~lla ssn DB87-29 52-29-50 121-3548 93AI 5 28 EdncyL(4kmN) 35578 DB87-30 52-29-54 121-38-55 93AI 5 2B EdncyL(45kmNwJ DBI DB7515-I2 525142 121-4340 93AI12 28 Jombis L (3km SE) DB2 DB757-1 52-32-19 121-42-28 93AI12 2B JmbicL(2kmEl DB3 DB757-2 52-32-13 1214238 93AI12 28 J&ic L (2 km E) DM DB751-2 5234.6 12147-3 93AIl2 28 Morrhsad L (25 km SW) DB5 DB757-3 52-32-10 121-42-21 93AI12 2B Jvobh L (2.25 km E) DB6 DB7532-2 52-31- 6 121-30-30 93AI12 28 Qusrnsl L * w (4 km SE PDIlcy L) 355095 AP87-rn749 52-22-40 121-31-51 93AI 5 2c BuvaCk(2kmM 35563 DB87-15 52-31.17 12143-9 93AI12 2c TioL(2hW) DB7 DB75IS-9 52-31-4 12143-26 93AIl2 2c IdiL(1.75kmSE) DB8 DB7515-2 52-31.16 12142.54 93AII2 2c IdisL (2km SE) RMll ~~73.34 52-25-14 121-31-6 93AI 5 2c Antoins L(N rid4 31608 AP85-12/44 52-2743 121-2744 93AI6 2D ShihL 35570 DB87-22 52.30-54 121-40-13 93AI12 2D W of Bmtjack st& DB9 DB7515-5 52-31-24 12141-22 93AI12 W Trio L (0.25 km W DBIO DB7512-1 52-37-51 121-5143 93AI12 W lrkPineL(1kmN) 35097 AP87-261os-sO 52-23-52 121-33-17 93AI.5 2E htoinc L (SW) 32050 AP8604/M18 52-26 3 121-23-40 93AI6 2E HmkcrL(2kmM 37024 AP8630n-113A 52-55- 9 121-2615 93AI 6 2E H-ny R RM2 RM73-29 52-23-46 121.33-13 93AI 5 2E Anloinc L (2km S) 316W AP85-59-57 52-27-21 121-28-4 93AI 6 20 ShikoL 31603 m48m6a7 52.27-30 121-28-5 93AI 6 2G ShikoL 31604 AP85.0810668 52-n.30 121-2801 93AI 6 20 ShikoL 35093 ~~87-09105.n 52-24-10 121-3159 93AI5 3 Anloinc L (S) 3m AP87-18ms41 52-1941 121-29-19 93AI6 3 HdY(2kmW) 36265 AP8707/04-20 52-1940 121-30-20 93AI5 3 HomeIly Rd 35092 AP87-oM)3-16 52-2040 121-2740 93AI 6 3A HOrxny (2 km W DBll DB753-1 52-35-27 12146-38 93AI12 3A Polley L (1.75km NNE) DB12 DB7M 52-34-32 12145-12 93AI12 3A Marehead L(I km SE) OB13 DB757-12 52-33-24 12143-28 93AIl2 3A MorcheadL(2kmS) DB14 DB757-14 52-33-29 12143-35 93AI12 3.4 MorehudL(2kmS) DBl5 118756-9 52.34.58 12145-11 93AI12 3A Morehad L(025 km SW) DB16 DB75bIO 52-35 2 121-45-6 93AI12 3A M" L (0.20 km SW) DBI7 DB7512-2 52-38- 4 121-5133 93AII2 3A lrkPireL(1.5kmN) DB18 DB756-12 52-35-32 121-4630 93AI12 3A Mor&adL(NWsnd) DB19 DB7522-5 52-34-24 121-40-53 93AI12 3B Mashad L (2.4km ESEl DB20 DB7522-3 52-33-26 121-40-11 93AI12 3B h1j;rk L (0.75 km W 35556 DB87-05 52-37- 4 12141.15 93AI12 4 LiulcL(2kmE) DB2l DB7533-1 52-37-28 12143-34 93AI12 4 LitlkL(0.75kmN) DB22 DB7518-2 52-3840 121-47-39 93AI12 4 la~kPine L (3.75km WE) 31599 AP85.51&56A 52-27-16 121-27-57 93AI 6 7 Shiko L 31618 m-7R-63 52-27-26 121-28-18 93AI 6 7 Shiko L 31602 Ap85-8/1" 52-27-32 121-2851 93AI 6 7 ShikoL 31605 p,Pssow2e 52-27-53 121-28.21 93AI 6 7 Shih L

Bulktin 97 129 (APPENDIX F continued)

52-37-38 121-38- 7 93AI127 52-37-38 121-38-7 Bullion pit 52-39-30 121-47-58 93AI12 7 93AI12121-47-58 52-39-30 QR 52-21-26 121-6.21 93AI6 7 Ho~llyMrn 52-21-30121-1638 %AI6 7 LcmwL(3kmND 52-25.49121-!M4 93AI6 7 V5wlandPk 52-2613 121-22-59 93AI6 7 Hmker L (0.5 !an SW) 52-25-13 12143-53OtOrgeL 8? 93AI5 52-26-48 121-46-30 8? 93AI5 BeavuL-ChoateL 52-23.52 121-28-30 93AI6 10 AnIoineL(S) 52-20-20 121-27-6 93AI6 10 Horsefly 52-26-4112147-51 93AI 5 10 Bmver L-waterline road 52-19-6 121-"33 93AI5 11 Horsenymad

- bnccio ,DX -pymrmr. Coliectoreoda: A. Ponrelcyev. AP: D.G.Boiley. DE: J. la. C: R.L Monon

130 Geological Survey Branch Ministry of Employment and Investment

APPENDIX G

MAJOR OXIDE CHEMISTRY OF MAP UNITS "

LAB FIELD MAP UNIT Si02 Fa-T MnO Me0 CaO pa05 Fez03 LO1 C@: TOTAL* -NO NO -- -Ti% a ------_ " 38434 m-24102.71 1A 46.92 0.75 16.64 8.39 0.18 5.68 13.06 1.76 1.32 0.22 5.52 2.25 5.28 1.81 1c0.20 35339 Cll-9 2A 46.52 0.64 1336 10.72 0.17 7.24 10.73 0.99 4.28 0.44 7.72 2.14 3.37 0.1'. 518.46 35340 CI1-ll 2A 46.49 0.76 11.59 12.59 0.21 8.35 10.69 1.51 3.59 0.26 9.29 2.26 3.36 0.0; 59.40 32641 Ap8621/04-66 2A 49.09 0.67 14.62 10.27 0.16 6.25 8.50 4.46 1.74 0.40 7.29 2.17 4.26 0.5t; 1C0.42 32642 AP8628104-92 2A 49.75 056 16.93 8.90 0.20 3.97 5.94 3.20 5.13 0.62 6.15 2.06 3.21 0.8' 5'8.41 32643 ~p8628m7-98 ZA 46.33 0.60 10.33 11.18 0.19 11.47 13.64 1.03 2.58 0.39 8.17 2.10 2.24 0.4:: 59.94 31607 AP8569iOI-72 2A 46.80 0.55 9.23 10.11 0.18 10.96 15.18 1.57 0.93 0.27 7.25 2.05 2.48 0.31 98.26 31609 m5-m-115 2A 49.28 0.97... 11.41 8.22 0.15 7.59 13.13 4.29 0.04 0.22 5.17 2.47 5.10 3.27 1C0.40 37026 Ae88oM15-19 2A 49.33 0.72 14.26 11.41 0.21 4.71 10.33 4.98 0.07 0.30 8.27 2.22 3.26 0.6:: 5958 38435 m8-22833-70 2A 47.04 0.55 15.17 9.38 0.16 7.40 13.15 2.25 0.38 0.14 6.60 2.05 4.42 I.oi 1CO.04 35553 DBglOl 2A &.& 0.65 13.40 11.38 0.22 8.00 9.87 256 2.19 0.27 8.31 2.15 2.76 0.21 59.78 35568 DB87-20 2A 47.81 0.58 9.88 10.86 0.20 10.52 13.38 1.67 1.55 0.47 7.90 2.08 2.81 0.34 59.73 35569 DB87-21 ZA 47.15 0.69 1322 11.68 0.21 9.16 11.42 1.76 1.89 0.33 8.54 2.19 2.28 0.E 99.79 35573 DB87-25 2A 46.09 0.63 17.80 9.41 0.19 4.52 10.07 2.79 2.77 0.37 6.55 2.13 5.02 0.28~ 59.66 35574 DB87-26 ZAnD 50.70 0.81 14.79 10.25 0.19 6.96 9.32 2.18 1.70 0.25 7.14 2.31 257 0.c 99.72 35575 DB87-27 ZAnD 51.69 0.73 15.02 9.44 0.25 5.43 7.16 2.77 2.42 0.31 6.49 2.23 3.85 0.26 99.07 35580 DB87-33 2Ai2D 50.81 059 17.06 8.73 0.13 4.71 8.08 3.63 2.58 0.31 5.97~~ 2.09 2.92 0.26 9955 35582 DB87-35 2ARD 48.44 0.69 16.50 11.17 0.13 5.49 8.50 3.80 1.48 0.38 8.08 2.19 2.83 0.56 99.41 35586 DB87-40 2ARD 50.01 0.83 1657 9.82 0.16 5.51 7.20 4.25 2.16 0.31 6.74 2.33 2.82 0.41 99.64 35325 c4-10 28 46.64 0.68 11.59 10.64 0.18 8.59 9.16 207 3.83 0.76 7.61 2.18 4.92 0.41 99.06 35326 C412B 28 47.14 0.78 13.72 11.36 0.20 6.23 9.25 4.65 1.29 0.70 8.17 2.28 3.34 0.21 98.66 35330 c7.3 28 47i3.i 0.62 13.45 10.56 0.21 5.71 10.05 2.41 3.96 0.53 7.59 2.12 3.73 0.64 98.59 32052 AP86WlO-29 2B 49.23 0.60 15.07 9.20 0.16 7.01 7.14 2.92 3.37 0.53 6.39 2.10 3.03 0.14 98.26 32053 AP86-10/084 2B 47.13 0.68.~~~ 13.64 11.87 0.26 6.26 9.94 3.27 2.72 0.41 8.72 2.18 3.10 0.88 99.28 32054 AP86-13/03-51 28 46ij9 0.69 12.86 11.70 0.18 8.29 11.03 1.75 2.50 0.17 8.56 2.19 2.62 0.95 9858 31597 AP85-ltl-35A 2B 49.19 0.57 11.15 10.18 0.16 9.21 12.96 3.51 0.65 0.41 7.30 2.07 2.37 0.7C 100.36 31611 AP85-22B-123 2B28 48.51 0.69 16.63 8.64 0.21 4.07 6.80 4.68 2.96 0.50 5.80 2.19 4.66 0.73 98.35 35577 DB87-29 45% 0.71 12.42 11.48 0.24 6.56 13.67 1.683.36 0.72 8.34 2.21 2.38 0.07 99.18 35578 DB87-30 28 47.99 0.62 9.65 10.93 0.19 10.35 11.92 2.142.04 0.52 7.93 2.12 3.08 0.14 99.43 DB1 DB7515-12 28 47.w 085"" 15.75 12.60 0.24 5.85 8.98 1.784.15 0.58 8.99 2.35 264 0.W 101.32 DB2 DB757-1 2B 48% 0.69 13.10 11.99 0.23 7.10 8.32 0.G 6.88 0.71 8.60 2.19 2.86 0.00 101.13 DB3 DB757-2 2B 48.70 0.69 12.90 11.07 0.19 9.50 10.25 2.55 2.12 0.72 7.77 2.19 2.49 0.00 101.18 DB4 DB751-2 28 45.70 0.77 11.70 13.40 0.18 7.90 12.65 2.52 1.63 0.67 9.79 2.27 3.14 0.00 10026 DB5 DB757-3 ZB 47.40 0.72 11.90 11.61 0.18 10.20 11.35 3.95 0.95 0.74 8.23 2.22 2.81 0.W 101.81 DB6 DB7532-2 2B 46.20 0.82 13.10 13.04 0.19 6.70 11.20 4.30 1.79 0.52 9.41 2.32 4.70 0.W 10256 35095 m7-20107-49 2c 50.77 1.00 18.50 8.62 0.23 3.19 6.81 5.40 1.82 0.50 5.51 2.50 2.79 0.61 99.63 35563 DB87-15 2c 46362c 0.72 17.12 10.22 0.20 5.35 8.25 3.83 2.38 0.44 7.20 2.22 4.58 0.48 99.45 DB7 DB7515-9 4820 0.62 13.75 11.06 0.23 7.85 12.65 2.00 3.12 056 7.83 2.12 2.22 0.00 102.26 DB8 DB7515-2 2c 48.40 0.81 17.80 11.30 0.24 4.85 8.65 5.00 0.64 0.47 7.86 2.31 3.04 0.00 101.20 RMI RM73-34 2c 51.43 0.75 15.76 9.41 0.17 3.86 6.65 3.87 4.80 0.386.22 2.25 2.12 0.00 93.20 31608 AP85-1214-84 2D 50.32 10.640.51 9.39 0.19 12.54 9.51 1.50 1.88 0.236.64 2.01 2.82 0.01 93.53 35570 DB87-22 20 47.60 0.68 10.31 12.11 0.20 9.59 14.14 2.09 1.51 0.428.94 2.18 0.86 0.07 9351 DB9 DBl515-5 20 46.50 12.W0.81 13.35 0.24 935 11.009.70 3.90 0.82 2.31 3.87 0.00 101.78 DBlO 2D 47.80 0.93 17.10 12.45 0.23 5.10 7.00 3.62 8.770.353.20 2.43 3.79 0.00 101.57 35097 2E 48.61 0.84 17.70 8.56 0.20 2.91 5.56 5.33 5.600.513.45 2.34 5.79 0.34 93.46

32050 "" ..." .~ 2E~~ 48.13 13.740.64 11.56 0.21 6.20 9.31 3.21 8.480.452.78 2.14 2.83 0.27 93.06 37024 Ae86-30/3-113A 2E 45.20 0.74 13.72 11.81 0.24 5.84 10.318.61 3.28 1.87 0.68 2.24 5.64 0.35 93.33 RMZ 2E 51.48 0.74 17.69 7.79 0.20 4.12 4.14 4.55 551 0.48 d~77... . 2.24 4~39... . 0.00 101.09 31My) 2G 2G55.18 0.64 17.31 9.03 0.24 4.05 5.21 5.11 1.30 0.236.20 2.14 2.48 0.01 IlW.78 31603 54.40 0.55 16.75 6.79 0.14 4.42 5.88 3.134.380.254.27 2.05 2.21 0.11 9.3.90 31601 20 48.07 0.76 16.23 9.28 0.19~~~. 556 11.18 1.132.91 0.57 6.32 2.26 2.67 0.01 9.3.55 9>35 35093~ ~~~ 3 48.96 0.80 16.36 9.19 0.24 3.71 8.20 2.884.440.396.20 2.30 4.18 0.62 35094 3 57.94 0.46 17.19 6.48 0.15 1.59 3.51 6.982.080.394.07 1.96 2.96 1.51 w.73 36265 3 .54-87 0.70 18.61 5.92 0.18 1.49 5.56 3.350.233.815.42 2.20 2.82 0.84 59.61 35092 3A 56.17 0.7 1758 7.79 0.17 2.96 5.78 4.970.251.764.72 2.27 1.93 0.62 93.88 DBl1 3A 47.70 0.76 17.40 9.35 0.22 4.40 7.82 4.303.60 0.64 6.15 2.26 4.99 0.00 101.14 DBl2 3A 46.00 as+ 15.60 13.05 0.26 6.20 9.93 3.05 3.63 0.56 9.25 2.49 2.10 0.00 101.37 101.72 DB13~ ~ ~~ 3A 51.90 19.400.75 8.83 0.22 2.63 6.87 5.30 2.62 0.33 5.70 2.25 2.87 0.00 DB14 DB757-14 3A 53.M 19.900.74 8.82 0.21 3.03 6.85 5.700.412.705.00 2.24 2.04 0.00 103.20

DB15 DB7569 3A 49.80 18.001.07 9.77 0.22 3.00 8.18 6.220.421.684.90 .~~ 2.57 3.26 0.00 IM).30

DB16 DB75610~~ ~~ ~~ 3A 48.60 0.84 1750 10.32 0.21 3.65 8.32 0.402.903.95 6.95 2.34 4.26 0.00 1W.95 DB17 DB7512-2 3A 50.00 0.83 17.80 10.21 0.24 4.45 5.10 5.30 3.32 0.38 6.86 2.33 3.86 0.00 10:1.49 DB18 DB756-12 3A 53.70 0.64 13.10 7.73 0.21 3.95 4.60 5.30 4.52 0.28 4.82 2.14 2.03 0.00 96.06 DB19 DB7522-5 38 47.10 0.82 18.40 11.79 0.25 5.05 8.72 1.98 3.93 0.29 8.29 2.32 2.87 0.00 10;1.20 DBZO DB7522-3 38 5050 0.88 1850 9.38 0.12 3.52 6.62 4.30 3.28 0.31 6.06 2.38 3.86 0.00 10127 35556 DB87-05 4850 0.80 16.67 10.48 0.22 4.40 7.88 4.17 2.38 0.52 7.36 2.30 3.65 0.49 $1.67 DB21 DB7533-1 47.90 0.95 16.90 11.96 0.21 4.15 7.95 4.18 3.22 0.53 8.31 2.45 3.92 0.00 101..87 DB22 50.40 0.73 14.20 12.48 0.17 5.80 8.40 4.90 0.91 0.38 9.00 2.23 2.96 0.00 101.33 31599 48.13 0.61 9.94 11.19 0.20 10.63 13.33 1.56 2.18 0.30 8.17 2.11 2.11 0.11 1Ml.IS 31618 52.20 1.04 14.98 10.22 0.22 6.16 9.25 2.97 1.82 0.30 691 2.54 1.32 0.01 1MI.48 316M 7 54.35 059 17.71 7.75 0.15 3.31 6.69 3.90 3.65 0.455.10 2.08 1.10 0.06 551.65 31605 7 935 0.68 15.61 10.90 0.21 4.95 9.31 2.48 3.65 0.457.85 2.18 0.47 0.34 99.06

31606 7 48.20~ ~~ 0.99 17.80 10.38 0.11 4.13 9.65 3.02 250 0.377.10 2.49 2.46 0.34 59.61 0.01 31610~~~~~ 5355 0.77 17.93 8.36 0.19 3.01 7.41 2.55 0.405.48 2.27 1.47 9935 37025 54.89 0.61 18.34 6.95 0.19 3.19 7.84 3.48 2.52 0.304.36 2.11 1.86 0.15 1MI.17 37030 4751 0.76 17.37 11.07 0.22 4.98 9.03 3.13 2.72 n49.. .- 7.93 2.26 2.42 0.15 99.70 38436 i 52.26 0.72 16.75 7.61 0.13 5.01 10.05 2.22 2.28 0.25 4.85 2.22 2.81 1.14 IMI.09 RM3 7 14.10 11.20 0.15 7.04 10.01 3.61 2.08 0.40 7.47 2.61 1.79 0.00 lMI.02 British Columbia

(APPENDIX G continued)

37027 AP88-08105.28 8 54.29 1.04 16.75 9.67 0.14 3.84 5.90 4.760.38 0.136.42 2.543.020.17 99.92 370% ~~8&1lm3-~8 13.920.63 S9.73 5.88 4.830.12 99.571.14 2.94 2.13 3.375.05 0.22 2.20 4.05

35091 AP8743fl102~~ 1Oa~~ 51.23~ ~~ 1.01 11.87 5.83 0.11 5.43 6.97 2.854.31 0.78 299 ~~2.518.747.53 ~ ~~99.13 ~ 350% AP87-24/9-68 lob 58.59 0.41 1741 5.31 0.19 1.15 5.66 4.W 2.30 0.18 3.06 1.91 4.24 1.77 99.57 37029 AP88-11/05-36 1of 45.54 1.11 11.43 9.11 0.16 8.86 8.77 2.63 0.96 0.89 5.85 2.61 8.94 5.60 98.40 35098 AP87-lWO8-U 11 48.55 2.04 13.06 12.71 0.17 8.43 8.92 2.91 0.77 0.33 8.25 3.54 1.88 1.71 99.77 VorOls calculorrd wing FeO-Tar Fe9 0, tor01 ImniPmcalc&edaFe203 =iiOio,+I.S(IrvinekBorogas1971)ondFcO-T(oJFeO*)=FeO+Fe20, *0.8998:Fe,O,*=Fe,O,+Fc0*1.1113S hlyticai mnhod. detection limit in bronlou inppm: values quored by mvllyieoi bbbomtory 1989. XRF- Bn(lO1, SN5). RMIO), CNIO). 7420). Y(lO), Nb(S), V(5J ii(10). INA .Ce(O.S), Csf0.5), Eu(O.2). Hfll),LOO). Lu(0.05),Sm(0.l). rs(O.2). TA(0.S).7’b(O.S), Th(O.Z), U(O.2). WZ), NDf51 AA .COc3). Ni(5) XRFondAA -lyse$: Geob~lcdSurveyBranch AdyticdSclence Iabomroq INAA -lyses: Bondor-Ckgg & Company DL, Wurcouver, 1988. dorX-RyAsmy Lobomtorior Ud,Don Milk, Onrorio, 1986 DnrO Sources: AP. Pantelrynr; DE - D. Boib; C - 3. Lu - this rtudy: lab no. with DB from Bailey (2978). Rmfmm Momn (1976). hlyscs by B.C. Gcologicnl Survey Branch Annlyticd Sciences labermmy

132 Geological Survey Branch Ministry ofEmployment adInvestment

APPENDIX H REPLICATE AND DUPLICATE ANALYSES (PRECISION AND VARIABILITY) "

LabNo. SiO, TIO, A1203 FeO-T MnO MgO CaO N%O 60 P,O, LO1 31602 54.3431602 0.55 7.6518.07 1.093.56 0.15 4 6.76 3.33 Duplicate 0.453.813.796.653.250.177.9817.8 0.63 53.2 1.1 Repeat52.3617.340.62 0.453.743.796.623.280.167.85 ----

37027 49.49 0.72 14.25 11.37 0.21 4.68 10.25 5.05 0.06 0.3 3.27 Duplicate 49.17 0.73 14.27 11.45 0.22 4.74 10.41 4.91 0.08 0.3 3.3

Analytical precisionfr x-rayfluorescencemethod quoted by Geobgical SurveyBranch, Analytical Sciences Laboralov, I992 -percent at midrange value: I% - Si0 2,AI 0 3, MgO,CaO, Na 0,MnO, P20,:5%-Fe,O3;2%-K2O,li0,:5%-LOI. LOI by combustion method(I050'C) &O.OI%

" Bulletin 97 133 r

British Columbia

134 Geological Suntq Branch APPENDIX I MINOR ELEMENT CHEMISTRY OFMAPUNITS . LA B FIELDLABMAPBa Ce Cs Cr V CO Eu HfLu La NIRb Sm Sc Ta Tb Th U Yb Sr V TI Nd Nb Zr NO NO INIT 38434AP88-24/02-7l IA 373 -_ 94270 35 24 - - 593 23.0 4496 - 5.0 57 35339 Cll-9 2A 2343 -- 207 276 64 74 - - 483 16.0 4182 _- 3.0 56 35340 CI1-ll 2A 71665 353 276 79 76 0.20.4 336 13.0 4182 " 0.1 38 32641 AP86-21/04-66 2A 950 22 5 321 24 57 1.0 0.5 7.0530 4016 - 16.071 32642 AP86-28/04-92 2A - -- -_ - - - - - " " 3357 -" 32643 AP86-28/07-98 2A 740 29 470 268 69 26 1.0 0.5 825 2.0 3596 _-20.0 57 31607 AP85-09/01-72 2A 770 14 273 253 38 13 0.1 1.3 533 5.0 3600 11.0 12.0 63 31609 AP85-20/2-1 I5 2A 30 19 1020 242 377 5 0.1 2.3 323 15.0 5100 9.0 6.0 IW 37026 AP88-06/05-19 2A 48 -- 22 302 IO 6 " 328 17.0 4316 38435 AP88-22/03-70 2A 126 - 156 245 60 II - -- 16.0448 3297 35553 0887-01 2A 1000 -. 170 247 23 41 - - 580 9.0 3893 35568 DB87-20 2A 1300 - 470 263 56 32 - - 500 23.0 3474 35569 DB87-21 2A 1100 -- 400 289 98 51 -- _- I200 24.0 4133 35573 DB87-25 2A 460 -- 5 250 11 35 " 420 23.0 3774 35574 DB87-26 2N2D 1200 -- 150 257 46 32 " "_ 575 19.0 4852 35575 DB87-27 2N2D 1900 -_ 100 273 26 45 - " 635 7.0 4373 35580 DB87-33 2M2D 720 -- 63210 22 51 -_ 570 9.0 3534 35582 DB87-35 2N2D 460 -- 92263 29 29 - - 645 15.0 4133 35586 DB87-40 2N2D 760 -- 271 5 22 1 - - Io00 12.0 4972 35325 C4-IO 2B 93947 288288 43 63 0.6 0.2 994 15.0 4316 35326 C4-128 2B 69827 73297 21 31 1.0 0.2 1147 15.0 4844 35330 C7-3 2B 1095 22 105 247 27 74 1.3 0.2 1482 14.0 4057 32052 AP86-06110-29 2B 860 36 270 287 82 66 1.1 0.5 I200 2.0 3596 32053 AP86-10/08-44 28 820 22 59354 32 32 0.9 0.5 890 20.0 4076 32054 AP86-13/03-51 28 I700 18 270330 63 54 0.1 0.5 IWO 2.0 4136 31597 AP85-lll-35A 2B 200 21 620 -- " 1 1.1 1.5 620 12.0 3300 31611 AP85-2213-123 28 1150 70 15 286 8 82 3.2 2.4 703 18.0 4300 35577 DB87-29 28 1000 -- 24985 24 74 -- __- 730 22.0 4253 35578 DB87-30 2B 760 -- 350266 71 27 " "_ 565 8.0 3714 DB I DB7515-12DBI 2B " " -_ " ." " " "_ - "_ 5091 DB2 DB757-1 28 " " -_ " "_ -._ " "_ " "_ 4133 DB3 DB757-2 28 " -_ _._" " " " _._4133 DB4 DB751-2 28 _- -_ _.__._ ""_ 4612 DB5 DB757-3 28 " _. " _._ - -_ " "_ 4312 DB6 DB7532-2 28 .- - .._ _" I ___ _- "_ 491 I 35095 AP87-20107-49 2c 660 60 5 I70 2 1 1.5 0.5 I133 30.0 5990 35563DB87-I5 2c 740 -- 2195 I5 52 -_ ___ 660 11.0 4313 DB 7 DB7515-9DB7 2c " - .__.._ -_ " " "_ 3713 DB 8 DB7515-2DB8 2c " " ___ I_ __ - " "_ 485 I RMI RM73-34 2c 1196 -_ " 99 I "_ 1231 22.0 4492 ...^* ...,, *. " " " .. _I,""., ,%'0-"1LI"O- L" :>;;; "_ 3" u.6 I.Y 3 i4.6 jiU6 35570 DB87-22 2D 500 -_ 49 44 -_ - 775 9.0 4073 DB9 DB7515-5 2D " -_ "_ -_ - " " ." 485 I DBIO DB7512-I 2D _- " "_ " -.-._ _- .__5570 (APPENDIX I Continued)

LA B FIELD LAB MAP Ba Ce Cs Cr V Co Eu Iff La Lu Ni Rb Srn ScTh Tb Ta U Yb Sr Y Ti NhNd Zr NO NO NO UNIT 35097AP87-26/05-80 2E IWO 50 1.7 5 189 30 0.2 2.0 18 0.05 2 88 4.4 9.1 1.1 0.1 2.2 2.1 0.5 1099 25.0 5032 --- 6.0 109 32050 AP86.04106-18 2E 1100 17 0.1 90 357 73 0.2 2.0 10 0.05 29 32 3.2 30.0 0.1 0.1 1.3 0.7 0.5 lI00 2.0 3836 ... 18.0 50 37024 AP86-3013-113A 2E 1653 _-- ._. I] 49 ...... _ ". 783 20.0 4436 ... 6.0 62

RM 2 RM73-29RM2~ ~~ ... ~. 2E 1534 -.. ." .. ." 84.~ ."." ." ." ." ...... 999 --- 4432______91 31600 AP85-5/9-57 2G 700 19 0.1 30 -.- 21 _..0.1 8 0.31 --. 40 2.7 29.2 0.1 ... 1.1 1.1 2.4 480 22.0 3900 9.0 4.0 _-- 31603 AP85-08/06-67 2G 1500 35 0.1 220 .--19 1.1 2.0 15 0.39 --- 1W 26.23.7 0.1 -.- 2.3 1.1 2.5 510 24.0 3500 13.0 4.0 --- 31604 AP85-08/06-68 2G 790 34 9.3 413334 27 1.1 2.0 0.3819 127 50 4.8 28.0 0.1 0.7 2.6 4.4 2.6 868 18.0 4400 17.0 7.0 80 35093 AP87-09/05-27 3 ...... ". 5 ...... 11.0 1.0 797 25.0 4796 ." 1.0 67 11 35094~~ ~. APR7-1810S-41.. 3 ...... _...... 21.0 6.0 515 25.0 2758 ... 12.0 70 36265 AP87-07/04-20 3 1096 -.- ." 14813 ...... 0.0 0.0 1150 25.0 4197 --- 16.0 188 35092 AP87-06/03-16 3A 1500 34 1.o 5 143 30 0.2 0.2 8 0.05 27 54 3.8 9.5 0.1 0.1 1.7 1.0 0.5 542 30.0 4612 ..- 10.0 132 DBll DB753-I 3A ...... "." ".." 4552 ". "._" DB12 DB756-6 3A ...... " ...... -.- ." ...... 5930 ...... DB13 DB757-I2 3A ."." _...... " __...... 4492 ...... DB14 DB757-14 3A ."." ...... " ." ."." 4432 ...... DB15 DB756-9 3A ."." ." ...... " ". ."." 6409 ...... DB16 DB756-IO 3A ...... " ." 5031 ......

DB17 DB7512-2~ ~~ ~ 3A _" "...... ". ". 4971 ...... DB18 DB756-12 3A ...... ". ." ...... 3833 ...... DB19 DB7522-5 3B ...... "...... 491 1 ...... DB2O DB7522-3 3B ...... " ...... ".." ...... 5271 ...... 35556DB87-05 4 1100 43 0.1 5 305 46 0.2 2.0 17 0.05 4 44 3.8 19.0 0.1 2.40.1 1.5 0.5 955 16.0 4792 --- 15.0 67 4 ." ". ." ...... " ." 5690 ...... 4 ". ." ." ...... 4372 ...... 8 82 --. ." 19924 ...... 64...... 242 28.0 6235 .". 8.0 124 8 1579 -.. ... m 128 ...... 44 38 ...... 612 18.0 3777 --- 17.0 116 31599 AP85-518-56A 7 900 14 1.9 600 .-- 65 0.6 0.1 7 0.22 ... 40 2.2 64.3 0.1 --- 0.9 0.5 1.5 410 12.0 3600 8.0 4.0 _..

...... 31618 APRS-7/2-63 7 1100 26 2.3 ~~170 ... 49...... 1.s 2.0 I I 0.49 ...... 1.2 3.3 390 26.0 7100 11.0 6.0 --- 31602 AP85-8/1-64 7 1500 27 1.6 10 -.-0.9 40 2.0 14 0.31 -.- 3.190 21.7 0.1 --- 2.6 1.4 2.2 770 19.0 3650 14.0 5.0 --- 31605AP85-08/02-69 7 I200 28 0. I 40 -.- 52 0.9 0.1 13 0.23 --- IW 3.4 38.3 0.1 -.- 1.2 0.9 1.9 780 16.0 4100 11.0 4.0 _-- 31606AP85-08/09-71 7 1100 23 0.1 7 0.931636 1.0 12 0.34 3 30.43.5 90 0.1 -.- 1.2 1.0 2.0 675 16.0 6400 13.0 11.0 71 31610AP85-21/2-120 7 1500 30 3.0 IO --- 35 1.4 2.0 17 0.38 --- 80 4.1 23.9 1.0 -.- 3.6 2.2 2.5 560 24.0 4600 21.0 6.0 -.- 37025 AP88-04/08-12 7 982 --- ." 21 211 ...... 2 46 ___ _.. ______...... 1109 22.0 3657 -.- 2.0 96 37030AP88-16/08-55 7 874 -.. ... 34031 ...... 7 ...... 1137 -.- 4556______40 38436 AP88-25/01-76 7 774 -.- ." 68 282 ...... 29 22 ___ ..______...... 6W 19.0 4316 _-.2.0 52 RM3 RM73-7 7 567 -.- ." 86 ...... 54 ...... _" ." 1075 21.0 6648 ...... 70

35091..~.~ APR7-03/01-04~ ~ 10a 2800 -.- ." 327138 ...... 87 102 ...... 2.0 ...... 14.0 4.0 I220 23.0 6050 .--235 9.0 ."". I? 35096 AP87-24/9-68 lob ". " ...... 36 44 ...... 0.1 ...... 19.0 6.0 586 22.0 2458 .-- 9.0 87 37029 AP88-11/05-36 IOC 5097 --- ". 520221 ...... 160 20 ...... 104423.0 6655 --. 9.0 164 35098 AP87-18/08-44 11 190 --- ." 297 191 ...... 147 7 ...... 0.1 ...... 10.0 0.5 481 22.0 I2219 --- 15.0 124 Analytical method, detection limit in brackets inppnl;values quoted by analytical laboratory1989. XRF. Ba(lOJ,S@), Rb(lO), CfilO),ZfiZO), Y(l0). Nbf5J.V(S), Ti(10). INA. Ce(O.S), Cs(0.5).E~(0.2)~ HJTIJ, Ld.2). fir(0.05). Sm(O.l), Sc(O.2). TAW),Tb(O.SJ, Th(0.2). lJ(0.2).YB(2), ND(5; AA - Co(3).NU) XRF andAA analyses: Geological Suwey Branch, Analytical Sciencekbomtory INAA analyses: Bondor-Clegg& Company Ltd., Vancouver,1988, and/orX-Ray Assay Iaborntories Ltd.,D& Mills, Ontario, 1986 Minislv of Empbymnt andhvesment "

APPENDIX J MAJOR OXIDEAND MINOR ELEMENT CHEMISTRY ~- SAMPLE Si Ti02 A120, FeO-T MnO MgO CeO NazO KzO PzOs FeO FQO, Nn 274 13.88 0.71 51.45 -9.29 8.00 0.16 239 0.40 2.54 - 11.37 218 50.75 0.65 12380.34 1.71 --2.31 10.80 10.M 0.17 -- 10.38 252 14.480.55 49.87 0.29 2.75 1.32--- 9.42 11.61 0.17 -- 9-36 05 0.61 52.67 10.250.30 1.42 ---3.40 10.42 8.64 0.18 -- 11.51 02 15.591.12 44.13 -. 3.0010.5110.51 0.21 0.60 0.34 -- 13.98 219 10.84OS5 51.45 0.40 2.01 2.56-. 9.75 9.28 0.18 - 10.84

407 14.02 0.95 50.46 ~~ ~~ - 8.37 0.15 10.80~ ~~ 1.27 2.69~~ ~~ 0.30 - 10.98~~ ~ ~ 3S8A 53.08 3S8A 0.54 14.58 -- 0.17 4.75 10.930.43 1.35 4.89 -- 9.28 W S70 53.76 WS70 os5 15.03 - 0.16 5.20 8.M 1.594.94 0.44 -- 10.25 Mo 50.03 0.47 13.21 -.- 0.17 13.53 8.59 0.90 0.242.56 - 10.30 374 52.82 0.55 11.89 -.- 0.19 9.18 11.320.34 1.05 2.13 -- 10.73 3588 48.15 0.85 14.64 -- 0.22 7.74 10.910.39 1.70 2.98 -- 12.42 409 52.44 0.65 12.76 -- 0.18 8.34 10.340.35 1.81 1.52 -- 11.61 395 51.73 395 0.81 14.01 -- 0.19 8.10 9.280.26 1.56 3.58 -. 10.47 269 45.92 0.49 10.97 -- 0.38 17.09 7.99 0.03 1.10 0.31 - 15.72 35K 46.88 0.75 14.68 - 0.22 7.87 9.w 0.383.98 0.80 - 15.40 48 49.57 0.78 14.97 - 0.18 11.54 9.160.46 1.42 0.67 - 11.25 275 48.85 275 0.40 9.82 - 0.18 17.01 10.680.17 1.65 0.35 - 10.89 260 50.95 0.52 15.57 -- 0.19 9.14 7.260.31 3.54 1.21 - 11.31 293 51.88 293 os1 13.79 - 0.19 9.23 8.92 1.38 2.37 0.32 - 11.42 16 50.39 16 0.79 13.08 - 0.17 8.20 10.83 3.16 2.21 0.37 - 10.79 15 53.74 15 0.86 15.54 - 0.16 6.45 7.84 2.72 3.42 0.40 - 8.57 185 48.70 0.46 11.28 -- 0.19 13.69 11.71 0.21 231 0.28 -- 11.16 172 54.36 0.72 13.79 - 0.17 6.34 9.18 3.61 0.412.03 -- 9.37 ws86 51.85 0.79 14.55 -- 0.20 5.46 10.400.37 0.58 4.78 -. 10.91 01 43.53 01 0.74 13.30 -. 0.24 16.30 12.55 0.61 0.60 0.23 -- 11.89 332 45.96 0.88 16.08 - 0.13 5.48 18.25 0.301.69 OS6 -- 10.68 25 46.16 0.79 13.95 -. 0.21 17.59 8.890.23 0.33 0.00 -- 11.85 Wyll 44.90 0.81 16.45 .-. 0.14 5.66 19.340.50 0.30 1.M - 10.85 AVERAG649.88 0.68 13.63 --. 9.680.19 10.43

n4 218 607.00 33.00 1089.00 CDm 19.00 29.00 430.00 143.00 - 276.00 252 829.00 66.W 424.00 am 21.00 53.00 CDm 320.00 -- 248.W 5 687.00 24.00 355.00 CDm 15.00 40.00 227.00 65.00 - 224.00 2 250.00 am 1064.00 2222- 17.00 35.00 137.0077.00 ... 384.00 219 624.00 44.00 44200 2222* 17.00 62.00 370.00 113.00 -.- 238.00 407 527.00 20.00 1947.00 8.00 14.00 23.00 111.00 56.00 -.- 321.00 358A 469.00 25.00 1821.00 CDm 16.00 26.00 23.00 21.00 -- 232.00 WS70 571.00 29.00 1923.00

Bulletin 97 137 ~~ ~

British Columbia

138 Geological Survey Branch APPENDIX K QUESNEL CIPWNO-WS FOR ALL ANALEED SAMPLES, n = 84 S AM PL E 274SAMPLE 358C 269 39.3252 409 3S8B 218 374 3WWS70 358A 407 5 219 2 175 48 264l 293 16 15 172 185 MAPUNIT IA 1AIA IA 1A IA 1A IA IA IA IA 1AIA IA IA 1A IA IA IA IAIA IA IA 1A OXIDESAS DETERMINED; (nd=nOt delemlncd) SI02 44.1352.6749.8750.7551.45 51.45 50.46 53.08 53.76 50.03 52.82 48.15 52.44 51.73 45.92 46.88 49.57 48.85 50.95 51.88 50.39 53.74 48.70 54.36 Ti01 0.71 1.120.66 0.61 0.55 0.55 0.95 0.54 0.55 0.47 0.55 0.85 0.65 0.81 0.49 0.75 0.78 0.40 0.52 0.51 0.79 0.86 0.46 072 A1203 14.4812.38 13.88 10.25 15.59 10.84 14.02 14.58 15.03 13.21 11.89 14.64 12.76 14.01 10.97 14.68 14.97 9.82 15.57 13.79 13.08 1554 1128 13.79 FQO~13.98 11.51 9.56 10.38 11.37 10.84 10.98 928 10.25 10.30 10.73 12.42 11.61 10.47 15.72 I5.40 11.25 10.89 11.31 11.42 10.79 8.57 11.16 9.37 MnO0.21 0.18 0.17 0.17 0.16 0.18 0.15 0.17 0.16 0.17 0.19 022 0.18 0.19 0.38 0.22 0.18 0.18 0.19 0.19 0.17 0.16 0.19 0.17 MsO 10.518.64 11.61 10.50 8.00 9.28 8.37 4.75 5.20 13.53 9.18 7.74 8.34 8.10 17.09 7.87 11.54 17.01 9.14 9.23 8.20 6.45 13.69 6.34 cao 10.5110.42 9.42 10.80 9.29 9.75 10.80 10.93 8.04 8.59 11.32 10.91 10.34 9.28 7.99 9.04 9.16 10.68 7.26 8.92 10.83 7.84 11.71 9.18 2.39 2.31 1.32 3.40 3.00NaaO 3.40 1.32 2.31 2.39 2.56 2.69 4.89 4.94 0.90 2.13 2.98 1.52 3.58 0.03 0.80 0.67 0.35 1.21 1.38 3.16 2.72 021 3.61 K201.42 2.75 1.71 2.54 0.60 2.01 127 1.35 1.59 2.56 1.05 1.70 1.81 1.56 1.10 3.98 1.42 1.65 3.54 2.37 2.21 3.42 2.31 2.03 PA 0.340.40 0.30 0.29 0.34 0.40 0.30 0.43 0.44 0.24 0.34 0.39 0.35 0.26 0.31 0.38 0.46 0.17 0.31 0.32 0.37 0.40 028 0.41 nd nd nd nd nd nd ndco2 nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd ndLO1 nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd nd TOTAL100.19100.00100.0299.40 99.99 97.86 99.99 100.00 99.% 100.00 100.20 100.00 IW.00 99.99 100.00 100.00 IOO.00 100.00 100.00 100.01 99.99 99.70 99.99 99.98

OXIDES RECALCULATED VOLATlLE FREE siq52.99 49.86 50.75 51.35 44.13 52.58 50.47 53.08 53.78 50.03 52.71 48.15 52.44 51.74 45.92 46.88 49.57 48.85 50.95 51.87 50.40 53.90 48.70 54.37 Ti02 0.71 0.66 0.55 0.61 1.12 0.56 0.95 0.54 0.55 0.47 0.55 065 0.65 0.81 0.49 0.75 0.78 0.40 0.52 0.51 0.79 0.86 0.46 0.72 AI203 13.85 12.38 14.48 10.31 15.59 11.08 14.02 14.58 15.04 13.21 11.87 14.64 12.76 14.01 10.97 14.68 14.97 9.82 15.57 13.79 13.08 15.59 1128 13.79 FhO3 11.35 10.38 9.56 11.58 13.98 11.08 10.98 9.28 10.25 10.30 10.71 12.42 11.61 10.47 15.72 15.40 11.25 10.89 11.31 11.42 10.79 8.60 11.16 9.37 MnO 0.16 0.17 0.17 0.18 0.21 0.18 0.15 0.17 0.16 0.17 0.19 022 0.18 0.19 0.38 0.22 0.18 0.18 0.19 0.19 0.17 0.16 0.19 0.17 MgO 7.98 10.50 11.61 8.69 10.51 9.48 8.37 4.75 5.20 13.53 9.16 7.74 8.34 8.10 17.09 7.87 11.54 17.01 9.14 9.23 8.20 6.47 13.69 6.34 cso 9.27 10.80 9.42 10.48 10.51 9.96 10.80 10.93 8.04 8.59 11.30 10.91 10.34 9.28 7.99 9.04 9.16 10.68 7.26 8.92 10.83 7.86 11.71 9.18 Na2O 2.39 Na2O 2.31 1.32 3.42 3.00 2.62 2.69 4.89 4.94 0.90 2.13 2.98 1.52 3.58 0.03 0.80 0.67 0.35 1.21 1.38 3.16 2.73 021 3.61 KIO 2.54 1.71 2.75 1.43 0.60 2.05 1.27 1.35 1.59 2.56 1.05 1.70 1.81 1.56 1.10 3.98 I .42 1.65 3.54 2.37 2.21 3.43 2.31 2.03 PA 0.40 0.34 029 0.30 0.34 0.41 0.30 0.43 0.44 0.24 0.34 0.39 0.35 0.26 0.3 I 0.38 0.46 0.17 0.31 0.32 0.37 0.40 028 0.41 TOTAL 100.00 100.00 100.00 IOO.OO IOO.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 CIPW NORM VOLATlLE FREE Q 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 1.32 0.00 2.82 0.00 0.00 0.00 1.17 0.00 0.00 0.57 0.00 0.00 0.00 0.00 or 14.98 10.10 1625 8.44 3.55 12.14 7.51 7.98 9.40 15.13 6.19 10.05 10.70 9.22 6.50 23.52 8.39 9.75 20.92 14.00 13.06 2027 13.65 12.00 nb 20.18 19.54 11.16 28.93 12.30 22.13 22.76 31.76 39.66 7.61 17.98 17.38 12.86 30.29 0.25 6.77 5.67 2.96 10.24 11.67 19.50 23.08 1.78 30.54 B" 19.62 18.37 25.47 8.57 27.32 12.43 22.44 13.86 14.16 24.45 19.75 21.56 22.66 17.56 26.55 24.72 33.65 20.36 26.61 24.44 14.99 20.16 23.02 15.44 ne 0.00 0.00 0.00 0.00 7.09 0.00 0.00 5.20 1.16 0.00 0.00 4.24 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 3.92 0.00 0.00 0.00 di 33.7615.5326.59 19.37 18.38 27.84 23.65 30.87 18.83 13.31 27.64 24.56 21.48 21.71 8.95 14.59 7.08 25.21 6.00 29.4814.41 13.10 26.74 22.30 3' 10.49 6.62 12.32 3.81 hy 12.32 6.62 10.49 0.00 11.36 7.80 0.00 0.W 22.58 21.48 0.00 23.40 0.94 32.65 1.60 37.31 20.86 24.51 29.37 0.00 11.9816.9916.25 5 01 9.00 1281 10.6113.85 23.54 8.17 8.97 4.65 10.95 11.79 0.00 15.30 0.00 14.00 19.20 21.94 0.00 16.08 6.18 0.0 12.54 1.5012.560.54 a Ill1 3.08 2.97 3.13 3.20 3.80 3.04 3.55 2.96 2.97 2.86 2.97 3.41 3.12 3.35 2.89 3.26 3.31 2.75 2.93 2.91 3.323.22 2.84 3.43 il 1.35 125 1.04 1.17 2.13 1.07 180 1.03 I .05 0.89 1.04 1.61 1.23 1.54 0.93 1.42 1.48 0.76 0.99 0.97 1.50 1.64 1.370.87 tq UP 0.93 0.79 0.68 0.70 0.79 0.95 0.70 1.00 1.03 0.56 0.79 0.91 0.82 0.61 0.72 0.89 1.07 0.40 0.72 0.75 0.86 0.650.94 O.% 3 AN= 49.29 48.46 69.52 22.86 68.95 35.96 49.65 30.38 26.31 76.26 52.34 55.37 63.80 36.71 99.05 78.51 85.59 8730 72.22 67.68 43.46 33.5892.8446.63 $

2ii 'I IS= iI (APPENDIX K Continued)

QuesnelClPWNormr SAMPLEWS86 1 332 15 WS41 AVE $8424 353393534031641 32642 32643 31607 31609 37026 38435 35553 35568 35569 35573 35574 35575 35580 35582 MAPUMT 1A 1A 1A IA 1A 1A 1.4 2A 2A 2A ZA 1A2.4 1A 1A 2A 2A1.4 1A 1A 1ARD 2ARD 2ARD 2ARD OXJDESASDETERMINED 11.2431 SIO246.16 45.96 43.53 51.85 44.90 46.49 49.09 49.33 47.04 48.48 47.81 47.15 46.09 50.70 51.69 50.81 48.44 0.79 0.74 0.88 0.79 Ti02 0.88 0.74 0.79 0.81 0.76 0.67 0.72 0.55 0.65 0.58 0.69 0.63 0.81 0.73 0.59 0.69 Ab03 13.9516.0813.30 14.55 16.45 11.59 14.62 14.26 15.17 13.40 9.88 13.22 17.80 14.79 15.02 17.06 16.50 F40311.85 10.68 11.89 10.91 10.85 2.26 2.17 2.22 2.05 2.15 2.08 2.19 2.13 2.31 223 2.09 2.19 FeO nd nd nd nd nd 9.29 7.29 8.27 6.60 8.31 7.90 8.54 6.55 7.14 6.49 5.97 8.08 MnO0.21 0.13 0.24 0.20 0.14 0.21 0.16 0.21 0.16 0.22 020 0.21 0.19 0.19 025 0.13 0.13 MgO 17.595.48 16.30 5.46 5.66 8.35 6.25 4.71 7.40 8.00 10.52 9.16 4.52 6.96 5.43 4.71 5.49 cao 10.40 12.55 18.25 8.89 19.34 10.69 8.50 10.33 13.15 9.87 13.38 11.42 10.07 9.32 7.16 8.08 8.50 Na10 4.78 0.61 1.69 0.00 I a4 1.51 4.46 4.98 2.25 2.56 1.67 1.76 2.79 2.18 2.77 3.63 3.80 Kz0 0.58 0.60 0.30 0.33 0.30 3.59 1.74 0.07 0.38 2.19 1.55 1.89 2.17 1.70 2.42 2.58 1.48 PlOS 0.37 023 0.230.56 0.50 0.35 0.22 0.44 0.26 0.40 0.62 039 0.27 0.22 0.30 0.14 027 0.47 0.33 0.37 0.25 0.31 0.31 0.38 co2 nd nd nd nd nd 1.81 0.14 0.07 0.56 0.84 0.42 0.38 3.27 0.62 1.07 0.21 0.34 0.07 0.28 0.07 0.28 028 0.56 LO1 nd nd nd nd nd 5.28 3.37 3.36 4.26 3.21 224 2.48 5.10 3.26 4.42 2.76 2.81 2.28 5.02 2.57 385 2.92 2.83 TOTAL 100.0199.9999.89 100.00 99.99 99.90 99.58 97.60 98.36 99.61 97.72 99.03 97.45 59.82 98.66 99.31 98.86 98.85 98.84 98.93 98.92 98.35 98.88 98.51 OXIDES RECALCULATEDVOLATLLE FREE Si0246.16 45.96 43.53 51.91 44.90 49.93 49.76 49.37 48.94 51.48 52.64 47.87 4928 52.03 51.71 49.57 50.45 49.78 48.83 49.08 52.62 54.70 52.95 50.63 Ti02 0.79 0.74 0.88 0.79 0.8 I 0.68 0.80 0.68 0.80 0.70 0.59 0.62 0.58 1.02 0.75 0.58 0.68 0.60 0.71 0.67 0.84 0.77 0.61 0.72 Ah03 14.57 13.30 16.08 13.95 16.45 13.64 17.65 14.18 12.20 15.33 17.91 10.67 9.72 12.05 14.95 15.99 13.94 1029 13.69 18.95 15.35 15.89 17.78 17.24 FqO, 10.92 11.89 10.68 11.85 10.85 11.24 2.39 2.27 2.38 2.28 2.18 2.17 2.16 2.61 2.33 2.16 224 2.17 2.27 2.27 2.40 236 2.18 2.29 FeO nd nd nd nd nd nd 5.85 8.19 9.78 7.65 6.51 8.44 7.63 5.46 8.67 6.96 8.65 823 8.84 6.97 7.41 6.87 622 8.44 0.20 0.24 0.13 0.21MnO 0.13 0.24 0.20 0.14 0.19 0.19 0.18 0.22 0.17 0.21 020 0.19 0.16 0.22 0.17 0.23 021 0.22 0.20 0.20 036 0.14 0.14 5.47 16.30 5.48 17.59MgO 5.48 16.30 5.47 5.66 9.69 6.02 7.68 8.79 6.55 4.20 11.85 11.54 8.01 4.94 7.80 8.32 10.95 9.49 4.81 7.22 5.75 4.91 5.74 cao 8.8918.25 12.55 10.41 19.34 10.44 13.85 11.39 11.25 8.91 6.29 14.05 15.98 13.86 10.83 13.86 10.27 1393 11.83 10.72 9.67 7.58 8.42 8.88 Ns10 4.79 0.61 1.69 0.00 1.04 2.10 1.87 1.05 1.59 4.68 3.39 1.06 1.65 4.53 5.22 2.37 2.66 1.74 1.82 2.97 2.26 2.93 3.78 3.97 Kz0 0.58 0.60 0.30 0.33 0.30 1.73 1.40 4.54 3.78 1.82 5.43 2.67 0.98 0.04 0.07 0.40 2.28 1.61 1.96 2.95 1.76 256 2.69 1.55 P2O s 0.37 P2Os 0.23 0.56 0.23 0.50 0.35 0.23 0.47 0.27 0.42 0.66 0.40 0.28 0.23 0.31 0.15 0.28 019 0.34 0.39 0.26 0.33 0.32 0.40 TOTAL 100.00 100.00 100.00 I00.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 lOOaO I00.00 100.00 100.00 100.00 100.00 l00.00 100.00 ClPW NORM VOLATILE FREE Q 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.M) 0.01) 0.00 0.00 1.41 2.27 0.00 0.00 or 3.55 3.43 1.77 1.95 1.77 10.23 8.27 26.84 22.33 10.78 32.08 15.75 5.79 0.25 9.54 11.57 17.43 10.43 15.13 15.89 9.14 ab 3.88 34.95 6.77 0.00 1.64 17.78 15.79 4.13 5.03 28.12 20.51 0.68 9.30 27.35 13.47 14.95 14.27 19.14 24.79 31.15 30.M 8" 31.79 16.56 35.41 37.10 39.34 22.69 35.65 20.56 15.00 15.47 17.66 16.48 16.21 12.43 15.51 23.40 29.69 26.53 22.66 23.60 24.67 2.99 0.702.99 4.08 0.00 3.90 0.00 0.00 2.58 4.56 6.20 4.41 4.51 2.54 5.94 0.67 0.25 5.89 0.00 0.00 1.93 0.46 8 :; 23.2126.87 42.22 4.40 43.79 21.73 25.56 26.82 31.91 21.27 7.61 40.83 4929 43.91 40.74 26.86 17.23 16.08 10.45 13.15 13.85 F hy 0.00 0.00 0.00 39.05 0.00 9.35 6.13 0.00 0.M) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20.77 19.07 0.00 0.00 9. 01 30.758.66 2.53 11.22 2.71 12.07 3.11 13.43 15.59 12.58 11.95 16.52 12.00 3.89 14.68 17.55 10.05 0.00 0.00 10.70 14.79 mt 3.253.32 3.45 3.32 3.35 3.16 3.46 319 3.45 3.30 3.16 3.15 3.13 3.78 3.14 3.29 3.483.29 3.42 3.16 3.32 a u 1.41 1.50 1.67 1.50 1.54 1.29 1.51 1.29 1.52 1.33 1.13 1.18 1.10 1.94 1.15 1.36 1.27 1.60 117 1.17 1.37 0.86 0.54 0.86 1.31 0.54 1.17 0.82 0.54 1.09 0.64 0.98 1.53 0.94 0.66 0.54 1.14 0.80 0.92 0.60 0.76 0.75 0.93 32.15 89.1332.15 83.95 100.00 96.10 56.06 69.31 83.27 74.89 35.48 46.27 96.02 63.55 31.24 53.52 61.02 67.54 58.09 47.75 43.11 45.09 (APPENDIX K Continued)

Queanel ClPW Norm SAMPLE 355863532535326 35330 3205232053320543159731611 35577 35578 UBI DE2 DE3 DE6DE5DE4 35095 35563 DE7 DE8 RMI 3160835570 MAPUMT ZARD 2D 28 28 28 28 20 28 2D 2D 2B 2B 28 28 2D ZB 2B 2C 2C 2C 2C 2C 2D 2D OXIDES AS DETERMINED SIO*47.36 47.14 46.64 50.01 49.23 47.13 46.79 49.19 48.51 45.96 47.99 47.90 4830 48.70 45.70 47.40 46.20 50.77 46.36 48.20 48.40 51.43 50.32 47.60 0.83 0.68 0.78 0.62 TI020.78 0.68 0.83 0.60 0.68 0.69 0.57 0.69 0.71 0.62 0.85 0.69 0.69 0.77 0.72 0.82 1.00 0.72 0.62 0.81 0.75 051 0.68 A1103 16.57 1159 13.72 13.45 15.07 13.64 12.86 11.15 16.63 12.42 9.65 15.75 13.10 12.90 11.70 11.90 13.10 18.50 17.12 13.75 17.80 15.76 10.64 10.31 Fez03 2.33 2.18 228 2.12 2.10 2.18 2.19 2.07 2.19 2.21 2.12 2.35 2.19 2.19 2.27 2.22 2.32 2.50 2.22 2.12 2.31 2.25 2.01 2.18 FeO 6.74 7.61 8.17 7.59 6.39 8.72 8.56 7.30 5.80 8.34 7.93 8.99 8.60 7.77 9.79 8.23 9.41 5.51 7.20 7.83 7.86 6.22 6.64 8.94 MnO 0.16 0.18 0.20 0.21 0.16 0.26 0.18 0.16 0.21 0.24 0.19 024 023 0.19 0.18 0.18 0.19 023 0.20 0.23 0.24 0.17 0.19 0.20 MgO 5.51 8.59 6.23 5.71 7.01 6.26 8.29 921 4.07 6.56 10.35 5.85 7.10 9.50 7.90 10.20 6.70 3.19 5.35 7.85 4.85 3.86 12.54 9.59 7.20 9.16 9.25 10.05cso 9.25 9.16 7.20 7.14 9.94 11.03 12.96 6.80 13.67 11.92 8.98 8.32 10.25 12.65 11.35 1120 6.81 8.25 12.65 8.65 6.65 9.51 14.14 4.25 2.07 4.65 2.41 Nul0 4.65 2.07 4.25 2.92 3.27 1.75 3.51 4.68 1.68 2.14 4.15 0.95 2.55 2.52 3.95 4.30 5.40 3.83 2.00 5.00 3.87 1.50 2.09 KlO 3.961.29 3.83 2.16 3.37 2.72 2.50 0.65 2.96 3.36 2.04 1.78 6.88 2.12 1.63 0.95 1.79 1.82 2.38 3.12 0.64 4.80 1.88 1.51 PI050.53 0.70 0.76 0.31 0.53 0.41 0.17 0.41 0.50 0.72 0.52 0.58 0.71 0.72 0.67 0.74 0.52 0.50 0.44 0.56 0.47 0.38 0.23 0.42 coz0.64 0.21 0.41 0.42 0.14 0.88 0.95 0.70 0.73 0.07 0.14 0.00 0.00 0.00 0.00 0.00 0.00 0.61 0.48 0.00 0.00 0.00 0.01 0.07 2.82 4.92 3.34 3.73 LO13.34 4.92 2.82 3.03 3.10 2.62 2.37 4.66 2.38 3.08 2.64 2.86 2.49 3.14 2.81 4.70 2.79 4.58 2.22 3.04 2.12 2.82 0.86 TOTAL 98.89 9821 97.7497.75 97.55 98.31 97.63 99.55 97.70 98.25 98.55 100.06 99.93 100.07 98.92 100.65 101.25 99.02 98.65 101.15 100.07 9826 98.79 98.52 OXIDES RECALCULATED VOLATILE FREE so,50.38 49.93 49.99 52.06 52.08 49.50 49.25 50.62 52.14 47.94 50.27 49.17 49.76 49.91 47.71 48.45 48.72 49.88 53.49 52.43 48.74 TI02 0.830.73 0.86 0.66 0.63 0.71 0.73 0.59 0.74 0.74 0.65 0.87 0.71 0.71 0.80 0.74 0.63 0.83 0.78 0.53 0.70 All03 14.3114.53 12.42 17.25 15.94 14.33 13.54 11.47 17.87 12.% 10.11 16.17 1350 13.22 12.22 12.16 13.90 18.34 16.39 11.09 10.56 Fez032.26 2.41 2.34 2.43 2.22 2.29 2.31 2.13 2.35 2.31 2.22 2.41 2.26 2.24 2.37 2.27 2.14 2.38 2.34 2.09 2.23 FeO8.07 8.65 8.16 7.02 6.76 9.16 9.01 7.51 6.23 8.70 8.31 923 886 7.% 10.22 8.41 7.91 8.10 6.47 6.92 9.15 0.17 0.19 0.21 0.22 MnO 0.21 0.19 0.17 0.17 0.27 0.19 0.16 0.23 0.25 0.20 0.25 0.24 0.19 0.19 0.18 0.23 0.25 0.18 0.20 0.20 MgO 5.74 921 6.60 6.07 7.42 6.57 8.73 9.48 4.37 6.84 10.84 6.00 7.31 9.74 8.25 10.43 7.93 5.00 4.01 13.07 9.82 cno 7.49 9.82 9.80 10.69 7.55 10.44 11.61 13.34 7.31 14.26 12.49 9.22 8.57 10.50 13.21 11.60 12.79 8.91 6.92 9.91 14.48 Nn20 4.42 2.22 4.93 2.56 3.w 3.43 1.84 3.61 5.03 1.75 2.24 426 0.98 2.61 2.63 4.04 2.02 5.15 4.03 1.56 2.14 KIO 2.25 4.11 1.37 4.21 3.57 2.86 2.63 0.67 3.18 3.50 2.14 1.83 7.09 2.17 1.70 0.97 1.85 1.89 2.53 3.15 0.66 4.99 1.96 1.55 PI05 0.32 0.81 0.74 0.56 0.56 0.43 0.18 0.42 0.54 0.75 0.54 0.60 0.73 0.74 0.70 0.76 0.54 0.52 0.47 0.57 0.48 0.40 0.24 0.43 TOTAL 100.00 100.00100.00100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 ClPW NORM VOLATILE FREE or 13.2924.26 8.07 24.89 21.07 16.88 15.55 3.95 18.80 19.98 12.63 10.80 35.98 12.84 10.06 5.74 10.96 11.18 14.95 18.64 3.90 29.50 11.58 9.14 sb 10.9832.33 25.48 9.53 25.50 13.69 11.89 20.66 27.43 0.00 14.55 23.16 0.00 20.32 10.57 17.25 10.55 39.20 20.17 5.69 32.59 21.82 13.22 9.18 8" 11.82 20.58 13.52 15.10 19.12 15.25 20.90 13.13 16.81 17.14 11.22 19.61 11.51 17.94 16.51 12.21 11.57 21.70 23.93 19.55 24.99 1193 17.46 14.64 ne 4.22 2.76 8.76~ ~ 6.59~~.. 0.34 8.32 2.00 5.36 8.19 8.03 2.39 6.98 4.48 O.% 6.33 9.16 14.70 4.48 7.73 6.18 5.96 6.62... . 0~00.. . . 4.84 ai 11.84 7.5.60 24.82 28.14 11.92 27.78 28.96 40.66 13.09 39.96 38.13 18.35 21.50 23.76 36.46 32.69 34.96 8.24 13.57 32.74 13.28 16.33 24.13 44.22 le 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.57 0.00 0.00 4.63 0.00 0.00 0.00 0.00 0.00 0.00 n.rm.." 0.00~ ~ ~ 0.00 0.00 0.00 hy 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 22.87 0.00 01 16.4813.32 12.57 9.94 16.35 12.43 15.58 11.08 9.64 7.85 15.40 14.60 15.61 17.89 13.52 16.54 10.95 828 13.72 11.62 13.15 8.03 6.16 12.46 mt 3.39 3.52 3.50 3.27 3.22 3.32 3.34 3.09 3.41 3.34 3.22 3.50 3;27 3.25 3.44 3.29 3.48 3.77 3.42 3.11 3.45 3.39 3.04 3.24 11 1.38 1.64 1.57 1.25 1.21 1.36 1.38 1.1 I 1.41 1.41 1.23 1.66 1.35 1.34 1.53 1.40 1.61 1.97 1.45 1.19 1.59 1.48 1.01 1.32 SP 1.90 0.75 1.73 1.31 1.31 1.00 0.42 0.98 1.25 1.75 1.27 1.39 I .70 1.72 1.63 1.76 1.26 1.21 1.09 1.32 1.13 0.92 0.56 I .00 AN= 51.86 38.89 34.67 61.31 42.85 52.70 63.74 38.85 38.00 100.00 43.53 45.85 100.00 46.88 60.97 41.45 52.31 35.63 54.26 43.4177.44 35.34 56.91 61.47 (APPENDIX K Continued)

QuesnolCIPWNorms SAMPLE DB9UBI035097 32050 37024 RMZ 31600 31603 316043509335094 36265 35092 DBll DB12DB13DB14DE15DB16 DB17 DBl8 DBZODB19 35556 MAPUNIT 2D 2D 2E2E 2E 2E 2G 2C 2C 3 3 3 3A 3A 3A 3A 3A 3A 3A 3A 3A 38 3B 4 OXlDESASDETERMlNED 46.50 47.80 48.61 48.13 45.20 51.48 55.18 54.40 48.07 48.% 57.94 54.87 56.17 47.70 46.00 51.90 53.50 49.80 48.60 50.00 53.70 47.10 50.50 48.50 0.81 0.93 0.84 0.64 0.74 0.74 0.64 0.55 0.76 0.80 0.46 0.70 0.77 0.76 0.99 0.75 0.74 1.07 0.84 0.83 0.64 0.82 0.88 0.80 12.00 17.10 17.70 13.74 13.72 17.69 17.31 16.75 16.23 16.36 17.19 18.61 17.58 17.40 15.60 19.40 19.90 18.00 17.50 17.80 13.10 18.40 18.50 16.67 2.31 2.43 2.34 2.14 2.24 2.24 2.14 2.05 2.26 2.30 1.96 2.20 2.27 2.26 2.49 2.25 224 2.57 2.34 2.33 2.14 232 2.38 2.30 9.70 8.77 5.60 8.48 8.61 4.77 620 4.27 6.32 6.20 4.07 3.35 4.97 6.15 9.25 5.70 5.70 622 6.95 6.86 4.82 829 6.06 7.36 0.24 0.23 0.20 0.21 0.24 0.20 0.24 0.14 0.19 0.24 0.15 0.18 0.17 0.22 0.26 0.22 021 022 0.21 024 0.21 025 0.12 0.22 9.75 5.10 2.91 6.20 5.84 4.12 4.05 4.42 5.56 3.71 1.59 1.49 2.96 4.40 6.20 2.63 3.03 3.00 3.65 4.45 3.95 5.05 3.52 4.40 11.00 7.00 5.56 9.31 10.31 4.14 521 5.88 11.18 8.20 3.51 5.56 5.78 7.82 9.93 6.87 6.85 8.18 8.32 5.10 4.60 8.72 6.62 7.88

3.90 3.62 .5.33 ~~ 3.21 ~ ~~ 3.28 4.55.." 5.1~~~~ I 3.13 2.91 2.88 6.9s... ~ 5.42~. .. 4.72 4.30 3.05 5.30 5.00 4.90 3.95 5.30 130 1.98 4.30 4.17

0.82 3.20 3.45 2.78 1.87 5.51 1.30 5.51 1.87 2.78 3.45 3.20 0.82 4.38~.~ 1.13 ~~~~ 4.44 2.08 3.81 1.76~~ ~ 3-60"" 3.63 2.62 2.70 1.68 2.90 3.32 4.52 3.93 328 2.38 Pa05 0.540.45 0.51 0.35 0.68 0.230.48 0.25 0.57 0.39 0.39 0.23 025 0.60 0.56 0.33 0.41 0.42 0.40 0.38 0.28 0.29 0.31 0.52 coa 0.00 0.000.35 0.27 0.34 0.00 0.01 0.11 0.01 0.62 1.51 0.84 0.62 0.00 0.00 0.00 0.00 0.w 0.00 0.00 0.00 0.00 0.00 0.49 3.87 3.79 5.79 2.83 5.64 4.39 2.48 4.39 5.64LO1 2.83 5.79 3.79 3.87 2.21 2.67 4.18 2.96 2.82 1.93 4.99 2.10 2.87 2.04 3.26 4.26 3.86 2.03 2.87 3.86 3.65 TOTAL 101.44100.31100.3298.3798.12100.0998.84 98.43 97.85 98.65 99.28 9924 99.33 100.20 100.M 100.84 102.32 99.32 99.92 100.47 95.29 100.02 100.33 98.8s OXIDES RECALCULATED VOLATILE FREE 50.51 48.74 53.67 56.53 60.15 56.91 57.6750.10 46.% 52.98 53.35 51.84 50.80 51.75 57.58 48.48 52.35 50.95 0.67 0.80 0.77 0.66 0.48 0.73 0.79 0.80 1.01 0.77 0.74 1.11 0.88 0.86 0.69 0.84 0.91 0.84 14.42 14.80 18.44 17.73 17.85 19.30 18.05 18.28 15.92 19.80 19.84 18.74 18.29 18.42 14.05 18.94 19.18 17.51 2.25 2.42 2.34 2.19 2.03 2.28 2.33 2.37 2.54 2.302.45 2.68 2.23 2.41 2.29 2.39 2.47 2.42 8.90 9.29 4.97 6.35 4.23 3.47 5.10 6.46 9.44 5.82 5.68 6.48 7.27 7.10 5.17 8.53 6.28 7.73 0.22 0.26 0.21 0.25 0.16 0.19 0.17 0.23 0.27 0.22 021 0.23 0.22 0.25 0.23 026 0.12 0.23 6.51 6.30 4.30 4.15 1.65 1.55 3.04 4.62 6.33 2.68 3.02 3.12 3.82 4.61 4.24 5.20 3.65 4.62 9.77 11.12 4.32 5.34 3.64 5.77 5.93 8.21 10.14 7.01 6.83 8.52 8.70 5.28 493 898 6.86 8.28 . ..~. .... 3.37 3.54 4.74 5.24 7.25 5.62 4.85 4.52 3.11 5.41 4.99 5.10 4.13 5.49 5.68 4.462.04 4.38 0.84 3.71 3.32 2.92 2.02 5.74 1.33 2.16 3.95 1.81 3.78 3.71 2.67 2.69 1.75 3.03 3.44 4.85 3.40 4.05 2.50 0.55 0.36 0.55 0.36 0.55 0.47 0.73 0.50 0.24 0.40 0.24 0.26 0.63 0.57 0.34 0.41 0.44 0.42 0.39 0.30 0.320.30 0.55 100.00 100.00 lW.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00lcQ.00 100.00 ClPW NORM VOLATILE FREE Q 0.00 0.00 0.00 0.00 0.00 0.00 0.72 0.39 0.00 0.00 0.00 0.00 4.34 0.00 0.00 0.00 nan.. . . oan .. . . n.. M. . 0.00 0.00 0.00 0.00 0.00 or21.91 19.59 4.97 17.24 11.92 33.95 7.87 26.90 7.02 27.77 23.3512.76 10.68 22.34 15.8021.W 15.91 10.33 17.91 20.31 28.64 23.90 20.09 14.77 ab 27.8320.4016.14 18.46 17.33 23.33 44.28 27.52 25.86 16.90 61.30 40.29 40.99 16.46 3.84 33.93 36.44 34.53 22.96 28.23 33.23 11.32 29.18 27.32 B" 15.2621.7313.15 15.62 18.55 12.08 20.97 19.47 29.31 19.70 15.789.81 22.18 18.44 21.8718.55 23.83 23.08 22.44 15.52 0.00 30.60 22.29 20.75 ne 11.176.13 9.57 5.44 6.82 9.10 0.00 0.00 0.00 4.81 0.00 3.93 0.00 11.78 12.19 6.41 .."3.11 4.67.... 6~40...~ 9.85 6.53 321 4.62 5.27 BC 0.00 0.00 0.00 0.00 0.0 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.46 0.00 0.00 0.00 dl 8.94 9.8431.91 24.50 26.24 4.93 3.27 7.41 20.43 17.05 4.70 9.31 4.60 14.93 23.09 8.92 6.12 13.52 14.91 6.a 18.42 9.91 7.96 13.84 hy 0.00 0.00 0.00 0.00 0.00 0.00 17.94 13.57 3.55 0.00 4.72 0.00 11.77 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 01 16.0217.99 828 13.15 12.45 10.63 0.00 0.00 7.52 7.69 1.94 2.13 0.00 9.65 13.54 7.53 9.03 6.88 9.13 13.41 6.65 15.33 9.83 11.70 mt 3.65 3.65 3.43 3.26 3.50 3.39 3.i8 3.09 3.44 3.53 2.95 3.31 3.38 3.44 3.69 3.33 3.24 3.88 3.55 3.50 2.10 3.46 3.58 3.50 1.58 1.83 1.71 I1 1.83 1.58 1.28 1.52 1.47 1.25 1.09 1.52 1.61 0.91 1.38 1.50 1.52 1.92 1.45 1.40 2.12 1.67 1.63 1.30 1.60 1.73 1.60 *P 1.28 0.85 1.29 1.10 1.71 1.17 0.55 0.61 1.40 0.96 0.94 0.56 0.60 1.47 1.33 0.79 0.95 1.02 0.97 0.92 0.70 0.70 0.75 1.27 AN= 35.4151.57 44.89 45.83 51.71 34.11 32.14 41.43 53.13 53.82 13.80 28.14 35.11 52.84 82.85 39.19 39.54 40.07 49.43 35.47 0.00 72.99 43.31 43.17 (APPENDIX K Continued)

Quesnel CIPW Norms SAMPLEDBZI DMZ 31599 31618 31602 31605 31606 3161037025 3703 38436 RM3 3702737028 35091 3509637029 3509% MAPUNIT7 7 4 7 4 7 7 7 77 7 7 8 8 loa 10b 1Oc 11 OXIDES AS DETERMINED 47.90 50.40 48.13 52.20 54.35 50.35 48.20 53.55 54.89 47.51 52.26 48.53 54.29 59.73 51.23 58.59 45.54 48.55 0.95 0.73 0.61 I .M 0.59 0.68 0.99 0.77 0.61 0.76 0.72 1.11 1.04 0.63 1.01 0.41 1.11 2.02 16.90 14.20 9.94 14.98 17.71 15.61 17.80 17.93 18.34 17.37 16.75 14.10 16.75 13.92 11.87 17.54 11.43 13.06 2.45 2.23 2.11 2.54 2.08 2.18 2.49 2.27 2.11 2.26 2.22 2.61 2.54 2.13 2.51 1.91 2.61 3.54 8.31 9.00 8.17 6.91 5.10 7.85 7.10 5.48 4.36 7.93 4.85 7.47 6.42 3.37 2.99 3.06 5.85 8.25 0.21 0.17 0.20 0.22 0.15 0.21 0.11 0.19 0.19 0.22 0.13 0.15 0.14 0.12 0.11 0.19 0.16 0.17 4.15 5.80 10.63 6.16 3.31 4.95 4.13 3.01 3.19 4.98 5.01 7.04 3.84 4.83 5.43 1.15 8.86 8.43 7.95 8.40 13.33 9.25 6.69 9.31 9.65 7.41 7.84 9.03 10.05 10.01 5.90 5.05 6.97 5.66 8.77 8.92 4.18 4.90 1.56 2.97 3.90 2.48 3.02 3.71 3.48 3.13 2.22 3.61 4.76 4.05 2.85 4.00 2.63 2.91 3.22 0.91 2.18 1.82 3.65 3.65 2.50 2.55 2.52 2.72 2.28 2.08 0.38 2.20 4.31 2.30 0.96 0.77 0.53 0.38 0.30 0.30 0.45 0.45 0.37 0.40 0.30 0.49 0.25 0.40 0.13 0.22 0.78 0.18 0.89 0.33 0.00 0.W 0.11 0.01 0.06 0.34 0.34 0.01 0.15 0.15 1.14 0.00 0.17 1.14 7.53 1.77 5.60 1.71 LO1 3.92 2.96 2.11 1.32 1.10 0.47 2.46 1.47 1.86 2.42 2.81 1.79 3.02 2.94 8.74 4.24 8.94 1.88 TOTAL 100.67 100.08 99.27 99.71 99.08 98.19 98.82 98.74 99.69 98.82 99.55 98.90 99.21 99.19 98.80 99.23 97.75 98.85 OXIDES RECALCULATED VOLATILE FREE Si0253.05 49.54 51.89 49.51 55.47 51.52 50.02 55.05 56.11 49.28 54.02 49.97 56.44 62.06 56.88 61.68 51.28 50.07 TI021.06 0.63 0.75 0.98 0.60 0.70 1.03 0.79 0.62 0.79 0.74 1.14 1.08 0.65 1.12 0.43 1.25 2.10 A120315.23 10.23 14.62 17.47 18.08 15.97 18.47 18.43 18.75 18.02 17.31 14.52 17.41 14.46 13.18 18.47 12.87 13.47 2.53 2.302.53 2.58 2.17 2.12 2.23 2.58 2.33 2.16 2.34 2.29 2.69 2.64 2.21 2.79 2.01 2.94 3.65 FeO7.02 8.41 9.27 8.59 5.21 8.03 7.37 5.63 4.46 8.23 5.01 7.69 6.67 3.50 3.32 3.22 6.59 8.51 MnO 0.22 0.180.22 0.21 0.15 0.21 0.11 0.20 0.19 0.23 0.13 0.15 0.15 0.12 0.12 0.20 0.18 0.18 Mgo 6.2610.94 5.97 4.29 3.38 5.07 4.29 3.09 3.26 5.17 5.18 7.25 3.99 5.02 6.03 1.21 9.98 8.69 C80 8.22 8.65 9.4013.72 6.83 9.53 10.01 7.62 8.01 9.37 10.39 10.31 6.13 5.25 7.74 5.96 9.88 9.20 NazO 5.05 4.32 1.61 3.02 3.98 2.54 3.13 3.81 3.56 3.25 2.29 3.72 4.95 4.21 3.16 4.21 2.96 3.00 KZO 3.33 0.94 2.24 1.85 3.73 3.74 2.59 2.62 2.58 2.82 2.36 2.14 0.40 2.29 4.79 2.42 1.08 0.79 pros 0.55 0.39 0.31 0.30 0.46 0.46 0.38 0.41 0.31 0.51 0.26 0.41 0.14 0.23 0.87 0.19 1.W 0.34 TOTAL 100.00 100.00 1W.W Iw.0 100.03 1w.w 1w.w loo.w 1w.w 1w.w 1oo.W IW.00 1W.00 loo.w lw.w 1w.w IO0.W 1W.W CIPW NORM VOLATILE FREE Q 0.00 0.M) 0.W 0.31 0.w 0.w 0.00 1.77 4.01 0.00 3.84 0.00 4.73 11.39 1.50 12.99 0.W 0.W or 19.67 5.54 13.26 10.93 22.01 22.07 15.33 15.49 15.22 16.67 13.93 12.66 2.33 13.51 28.28 14.31 6.39 4.69 ab 18.21 35.41 8.36 25.53 33.67 20.00 22.27 32.26 30.09 19.09 19.41 20.41 41.86 35.59 26.77 35.62 25.05 25.38 a" 18.46 14.50 14.09 22.54 20.47 21.18 28.69 25.45 27S9 26.27 29.99 16.62 24.15 13.84 7.64 24.35 18.64 20.94 "0 9.93 3.93 2.83 0.00 0.W 0.79 2.29 0.00 0.00 4.54 0.W 5.98 0.w 0.w 0.00 0.00 0.00 OM) Be 0.00 0.00 0.w 0.00 0.w 0.00 0.w 0.00 0.00 0.w 0.w 0.w 0.00 0.w 0.w 0.00 0.w 0.w di 15.58 21.36 42.01 18.00 8.56 19.07 15.26 7.98 8.31 13.94 16.07 25.87 4.44 8.55 19.82 3.32 19.05 18.12 hr 0.00 0.W 0.W 16.26 6.56 0.W 0.00 11.23 9.78 0.W 11.45 0.00 16.31 12.16 7.84 5.27 17.52 16.73 01 11.37 13.62 14.42 0.M) 3.47 11.29 9.59 0.00 0.00 13.43 0.w 11.47 0.00 0.w 0.00 0.00 4.41 4.07 rnt 3.67 3.33 3.15 3.74 3.08 3.23 3.75 3.38 3.13 3.40 3.33 3.90 3.83 3.21 4.04 2.92 4.26 5.29 I1 1.86 1.43 1.19 2.01 1.14 1.32 1.95 1.50 1.18 1.50 1.41 2.17 2.05 1.24 2.13 0.82 2.37 4.w .^^ " -. . "- . ~- ^^^ ~~, . .- "," ~",~ ^^ -.. -~.~ -~ 1.10 ".I. ;.;i xi I.", I.", ".)I" "2" ".,I 1.10 ".W Y.7" ".>A ?.X iDi "C '.A" ".,l I AN- 50.33 29.M 62.76 46.89 51.4337.80 47.8444.1056.29 44.8760.7157.91 36.59 27.99 2'2.19 42.6740.60 45.21 iI (APPENDIX K Continued)

SAMPLE AVE AVE AYE AYE AVE AVE AVE AVE AVE AVE AVE AVE AVE AVE AVE AVE AVE AVE MAPUNIT 1A 2A 2Aj2D 28 2C 2D 2E 2G 3 3A 38 4 7 8 loa lob 10e 11 OXIDES AS DETERMINED SIO* 47.5150.3347.7049.78 49.03 48.06 48.36 52.55 53.92 50.82 48.80 48.93 51.00 57.01 51.23 58.59 45.54 48.55 TI02 0.69 0.66 0.73 0.70 0.78 0.73 0.74 0.65 0.65 0.82 0.85 0.83 0.79 0.84 1.01 0.41 1.11 2.04 Ah03 13.73 13.17 15.99 13.04 16.59 12.51 15.71 16.76 17.39 17.36 18.45 15.92 16.05 15.34 11.87 17.54 11.43 13.06 FeA 11.23 2.16 2.23 2.20 2.28 2.23 2.24 2.15 2.15 2.32 2.35 2.33 2.29 2.34 2.51 1.91 2.61 3.54 7.48 6.88 8.08 FOO 6.88 7.48 6.92 8.51 6.87 5.60 4.54 6.29 7.18 8.22 6.52 4.90 2.99 3.06 5.85 8.25 MnO0.20 0.17 0.19 0.19 0.21 0.22 0.21 0.19 0.19 0.22 0.19 0.20 0.18 0.13 0.11 0.19 0.16 0.17 9.55 7.70 5.62 7.47 MsO 5.62 7.70 9.55 5.02 9.25 4.77 4.68 2.26 3.81 4.29 4.78 5.24 4.34 5.43 1.15 8.86 8.43 cao 10.52 11.23 8.05 10.29 8.60 10.41 7.33 7.42 5.76 7.05 7.67 8.08 9.26 5.48 6.97 5.66 8.77 8.92 NarO 2.09 2.54 3.33 2.97 4.02 2.78 4.09 3.72 5.09 4.65 3.14 4.42 3.01 4.41 2.85 4.00 2.63 2.91 1.71 2.09 2.07 2.61 K,b2.07 2.09 1.71 2.55 1.85 3.40 2.27 3.44 2.97 3.61 2.17 2.60 1.29 4.31 210 0.96 0.77 0.34 0.34 0.31 0.57 PlOS 0.31 0.34 0.34 0.47 0.39 0.53 0.35 0.34 0.40 0.30 0.48 0.37 0.18 0.78 0.18 0.89 0.33 COa 1.81 0.64 0.32 0.30 0.22 0.02 0.24 0.04 0.99 0.07 0.00 0.16 0.23 0.66 7.53 1.77 5.60 1.71 LO1 5.28 3.43 3.00 3.24 2.95 2.84 4.66 2.45 3.32 3.04 3.37 3.51 1.78 2.98 8.74 4.24 8.94 1.88 TOTAL 99.89 98.70 98.71 98.88 99.43 99.77 98.91 98.79 99.06 99.75 100.18 99.87 99.08 99.20 98.80 99.23 97.75 98.85 OXIDES RECALCULATED VOLATILE FREE Si0249.68 52.59 50.08 49.92 50.83 49.59 51.29 54.52 56.29 52.56 50.42 50.78 52.40 59.25 56.88 61.68 51.28 50.07 Ti020.73 0.76 0.69 0.69 0.81 0.76 0.79 0.68 0.69 0.85 0.88 0.86 0.81 0.87 1.12 0.43 1.25 2.10 Ab03 13.6s16.7013.84 13.78 17.21 12.92 16.67 17.40 18.16 17.93 19.06 16.53 16.50 15.94 13.18 18.47 12.87 13.47 Fez03 2.2711.24 2.302.33 2.36 2.30 2.38 2.23 2.25 2.40 2.43 2.42 2.35 2.43 2.79 2.01 2.94 3.65 FeO -...- 7.84 8.44 7.19 7.17 8.78 7.30 5.81 4.75 6.50 7.41 8.53 6.71 5.09 3.32 3.22 6.59 8.51 MnO 0.19 0.20 0.21 0.18 0.22 0.22 0.23 0.20 0.20 0.23 0.19 0.21 0.18 0.14 0.12 0.20 0.18 0.18 Me0 9.57 8.07 7.80 5.87 5.19 9.54 5.06 4.86 2.38 3.94 4.43 4.96 5.39 4.51 6.03 1.21 9.98 8.69 C*O 10.758.41 11.78 10.55 8.89 10.73 7.80 7.73 6.03 7.28 7.92 8.38 9.52 5.69 7.74 5.96 9.88 9.20 NazO3.10 3.47 2.67 2.09 4.18 2.86 4.35 3.85 5.314.58 3.25 4.81 3.09 4.58 3.16 4.21 2.96 3.00 X202.74 2.16 2.19 1.72 2.64 1.92 3.60 2.36 3.602.26 3.73 3.08 2.67 1.35 4.79 2.42 1.08 0.79 PA0.33 0.36 0.35 0.60 0.49 0.40 0.56 0.37 0.35 0.42 0.31 0.50 0.38 0.19 0.87 OS9 1.00 0.34 TOTAL 100.00100.00 100.00 100.00 100.00 100.00 1w.m 100.00 100.00 100.00 IW.00 100.00 100.00 100.00 100.00 1w.m 100.00 100.00 CIPW NORM VOLATlLE FREE Q 0.19 0.00 0.74 0.00 0.00 0.00 0.00 0.37 0.00 0.48 0.00 0.00 0.99 8.06 1.50 12.99 0.00 0.00 or 10.15 12.97 12.78 15.78 15.63 11.32 21.26 13.93 21.29 18.20 22.00 13.33 15.76 7.92 28.28 14.31 6.39 4.69 ab 15.73 16.41 27.49 15.10 23.89 14.74 21.74 32.55 39.50 27.85 20.25 26.98 23.11 38.73 26.77 35.62 25.05 25.38 8" 23.12 19.29 23.61 15.21 20.42 16.75 15.38 23.25 15.10 18.43 26.45 17.90 23.29 19.00 7.64 24.35 18.64 20.94 ne 6.05 1.03 3.36 1.07 6.19 5.14 8.13 0.00 2.91 6.78 3.92 6.38 1.64 0.00 0.00 0.00 0.00 0.00 BF 0.m 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.27 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 21.91 29.89 13.07 27.92di 13.07 29.89 21.91 16.83 27.53 16.15 10.37 10.35 12.35 8.94 16.93 17.51 6.50 19.82 3.32 19.05 18.12 IC 0.W 0.00 0.00 0.33 0.00 0.00 0.00 0.00 0.00 0.00 0.00 om 0.00 0.00 0.00 0.00 0.00 0.00 hy 11.83 0.20 7.97 0.00 0.00 5.72 0.00 11.69 1.57 1.31 0.00 0.00 5.53 14.24 7.84 5.27 17.52 16.73 01 9.85 12.47 7.76 13.53 10.96 13.16 11.13 2.51 3.92 8.42 12.58 12.23 617 0.00 0.00 0.00 4.41 4.07 mt 3.18 3.29 3.38 3.33 3.43 3.34 3.45 3.24 3.26 3.35 3.52 3.50 3.41 3.52 4.04 2.92 4.26 5.29 11 1.31 1.31 1.39 1.45 1.54 I .44 1.50 1.29 1.30 1.61 1.67 1.63 1.65 1.54 2.13 0.82 2.37 4.00 0.81 0.84 0.76 1.40 0.76BD 0.84 0.81 1.13 0.93 1.32 0.85 0.82 0.97 0.73 1.15 0.89 0.43 2.M 0.44 2.34 0.79 61.92 58.13 46.59 54.69 49.22 53.71 41.77 42.23 31.92 41.61 58.15 40.85 51.06 32.29 22.19 40.60 42.67 45.2142.6740.60 22.19 32.29 51.06 40.85 58.15 AN-41.61 31.92 42.23 41.77 53.71 49.22 54.69 46.59 58.13 61.92

*CIPWnorma cnicuiated by GSBprogram (Don Maclnlyre 1592) ~~Av~ragrseolcuiot~dfor&1anoiy~~~plur29onalysesofunlllAfromBioodgood,1987.AVE-aver~g~vnlueforUnil ***Fe20, volussfor,millA-Fo,O, Toral:nd=noldelennined APPENDIX L ANALYSISOF FERRIC AND FERROUS IRON and Fe'?, IN PERCENT, FROM QUESNEL VOLCANIC AND INTRUSIVE ROCKS

COMPARED TO VALUESCALCULATED FROM TOTAL Fe @eo*) " FeO Fe203 FeO Lab No Map unit AnalyzedCalculated Analyzed Calculated 31597 2b 4.5 7.3 5.2 2.1 5.2 7.3 4.5 2b 31597 2a 4.9 5.8 3.2 2.2 3.2 5.8 61 14.9 2a 2a 5.4 7.3 4.1 2.1 4.1 7.3 6075.4 2a 2a 6.1 5.2 1.5 2.5 1.5 5.2 6096.1 2a 2g 4.2 6.2 4.3 2.1 4.3 6.2 6004.2 2g 2g 3.4 4.3 6033.4 2g 3 2.1 2g 4.1 6.3 4.7 2.3 4.7 6.3 6044.1 2g 2d 5.9 6.6 2.9 6.6 6085.9 2d 2 599 7 5.2 599 8.2 5.4 2.1 602 7 5.1 3.6 3.7 2.1 605 7.9 7 5.3 5 2.2 4.6 7.1 5.2 2.5 7 5.2 606 7.1 4.6 4.4 5.5 3.5 2.3 3.5610 5.5 7 4.4 Convention used - Imine and Baragar(1971): FeO* or FeOT reported as Fe203; Fe203= approximately Ti + 1.5 and FeO* = FeO + Fe, 0, x 0.8998and Fe203*= Fe, 0, + FeOx 1.11135 British Columbia

146 Geological Survey Branch Ministo of Employment and Invesrrnenf "

APPENDIX M

LITHOGEOCAEMICALANALYSES(125 ASSAY SAMPLES), IN ppm "

LAB FIELD Au Ag Cu Pb Zn Co Ni Mo Hg As Sb, Ba

31617 < < 110 70 10 16 21 0 0 0 <: 0 32647 *84 < 0 000 00 82 0 <: 0 32649 21 < 0 000 00 101 o< 0 3265 1 < < 0 000 00 20 o< 0 34904 < < 61 11 88 0 o< 60 51 .S 449 34907 < < 67 < 66 0 o< 250 4 c 125 34909 < < 5057 10 0 o< 19 51 1C 391 34917 < < 32 120 11 0 o< 15 *90 1 828 37033 1 < 27 8 62 0 00 88 23 3 1169 37385 3 < 32 10 97 0 *1214 *328 4 3 349 37034 1 1 111 *42014 0 00 *370 15 6 437 37036 1 < 25 93 6 0 00 50 17 1C 124 37037 *260 2 3468 6 0 00 324 6 2 263

37038~ ~~ ~ 1 < 11868 6 0 00 115 11 2 811 37043 88AP-13/07-AX12 1 < 12879 6 0 00 116 15 3 860 37044 88AP-15/02-AX13 1 A 101 8 69 0 00 *330 8 4 269 38432 88AP-26/13-AX19 *40 1 55 *48 *128 0 00 *683 62 *34 1635 38433 88AP-3U07-AX20 1 .8 134 12 96 0 00 46 1 3 840 38526 88AP-11/06-37-AX21 32 .5 26 7 97 0 00 38 9 c 260 3.5303 C10-1B < < 112 9 124 0 o< < 17 .C 0 35335 c10-IC < < *246 4 87 0 18 < < << 0 35304 C10-ID < < 32 12 90 0 o< < 24 .9 0 35305 ClO-1E < < 7584 16 0 o< 183 10 < 0 35306 CIO-IF 30 < 26 79 12 0 0 10 44 *78 1 0 35307 C10-2D f50 < 12595 17 0 o< 154 33 1.6 0 35307 C10-2E 30 < 42 17 72 0 o< 26 13 .7 0 35314 C13-2B *40< < 812 12 0 o< 10 o< 0 35315 C13-4 < < 1167 13 0 o< 13 2 .9 0 35316 C13-6 < 10 17 80 0 o< 18 9 1.6 0 35343 C13-7 < < 54 *1336 0 12 < < 6 2.5 0 35317 C13-8B 30 < 17087 10 0 o< 35 5 .7 0 3491 1 87AP-18/11-AXlO < 5 *880 122 15 0 o< *1554 *45*78 74 37042 9 < 122 6 104 0 00 17 8 < 622 37045 1 2 52 53 6 0 00 142 *112168 .9 37046 1 1 104 8 71 0 00 315 45856 3 38428 1 1 54 11 100 0 00 30 2 1 873 38429 1 1 63 13 87 0 00 13 2 2 741 38430 88AP-23/02-AX17 *55 1 154 101 12 0 00 132 32 2 408 35336 C10-3A *40 < 62 16 24 0 *205 < 605.3 13 0 35337 C10-3B 20 < 15 15 83 0 << 76 86 0 35338 C10-3D 30 < 8960 4 0 4< 11 33 0 35318 Cll-4 30 < 140 11 98 0 o< 19 10 2.8 0 31615 85AP-19/1-110-AX7 < < 164 22 85 30 25 0 0 26 < 0 31616 85AP-19L3-llOB-AXS < < 12695 21 23 22 0 0 << 0 32048 86AP-9/4-37-AXl < < 44 5 63 0 *480 c *380 0 *85 0 32049 86AP-125-48-AX2 < < 70 8 58 0 19 < *380 << 0 32648 86AP-23/4-AX4 38 < 0 000 00 27 << 0

32650 86AP-26/2-86-AX6 < < 0 000 00 38~~ << 0 32652 86AP-38/1-145-AX8 33 < 0 000 00*0.93% << 0 32653 86AP-41/1-161-AX9 < < 0 000 00 28 1 08 0 32654 86AP-4U2-165-AXlO < < 0 000 00 252 *0.21% < 0 34905 87AP-13/2-AX04 < < 42 17 59 0 o< 10 45 < 523 34906 < < 30 11 64 0 0 *56 170 *90 5 *1.2:4% 34914 < < 79 127 7 0 o< 29 18 < 851 34915 < < 147 18 60 0 o< 72 13 < 832

" Bullefin 97 147 British CoMia

(APPENDIX M continued) LAB FIELD Au Ag Cu Pb Zu Co NiHg Mo As Sb Ba NO NO

3491687AP-M/3-66-AX15 < < *430 16 95 0 o< 91 *78 2 843 3491887AP-28/1-87-AX23 < <11 21 *130 0 o< 11 40 2 980 3703988AP-O8/03-AXW 1 < 116 8 85 0 00 13 8 5 943 3704088AP-08/04-AXlO 1 < 80 8 81 0 00 15 5 2 210 35325 c4-IO < < 8 14 105 0 50 < 10 11 1.8 0 35301C4-12 < < 9 *28 *187 0 o< < 19 3.4 0 35326 C4-12B 30 < 13 8 105 0 19 < < 14 .6 0 35328C6-2C 20 < 90 9 89 0 50 < < 1 < 0 35329C6-3A 20 < 19 14 80 0 92 < < I2 .8 0 35330 c7-3 < < 10 168 97 0 23 < 48 *284 < 0 35312 Cll-17 20 < 12 13 81 0 o< 127 20 .7 0 35341 < < 22 8 77 0 << < 13 .9 0 31613 < <11 117 87 23 13 0 0 0 < 0 31614 < < 13 138 87 44 22 0 0 60 < 0 34908 87AP-1611-AXO7 <<167 10 100 0 o< 16 5 < 640 34910 87AP-4/1-AX09 <<145 22 118 0 o< 18 40 1 699 34798 87AP-25I2-AX17 < *25 170 20 0 0 o< 6 *lo6 6 *5970 34799 87AP-25/2-AX18 < *70 *30 30 0 o< '970 55 10 1031 34800 87AP-26/6-AX19 < *44 47 *30 100 0 o< 165 '74 6 689 34801 87AP-26i7-AX20 << 54 *38 50 0 o< 10 *194 10 743 34802 87~~-26n-~x21 <9 66 *42 100 0 o< *360 22 10 81 34803 87AP-26fl-AX22 <6 83 *39 80 0 oc *340 57 *13 110 30118 .AP85-65-AX3 << 18 < 9 0 00 0 0 < 0 30119 AP85-664x4 << 36 < 8 0 00 0 0 C 0 30116 AP85-14-AX1 << 7 < 17 0 00 0 30 < 0 37041 88AP-lUO1-38-AX10A 1< 10 6 77 0 00 220 16 .9 118 34902 << 42 22 *I51 0 o< 78 *lo8 2 692 34912 <1 27 9 30 0 o< 12 51 < 252 34913 <1*2100 7 64 0 o< 54 6 C 975 35321 (3-3 20 < 58 20 90 0 140 < *560 2 2.8 0 35322 c3-4 20 < 85 6 82 0 33 < 15 30 .6 0 35323 cilo << 14 10 78 0 << 78 11 4.2 0 35324 c4-2c << 7 10 466 0 << < 30 .6 0 35309 C1 I-SA 30 < 102 74 0 o< < 7 .7 0 35339 Cll-9 *40 < 123 9 95 0 70 < 12 5 < 35310 Cll-10 <<108 12 85 0 o< < 13 < 35340 c11-11 <<*510 8 75 0 82 < 17 12 < 35311 Cll-12 30 < 82 113 0 o< C 7 < 35313 Cll-13 20 < *440 218 107 0 o< 165 20 .5 35348 G8-1 20 c *22 1 5 76 0 59 < 16 14 < 35349 G8-3 << 15 7 46 0 3< 20 23 1.7 35350 G8-4 M<*295 8 98 0 52 < 2 19 0.8 0 34903 87AP-814-AXO2 << 40 3 59 0 o< 43 45 < 956 34804 DB87-010 < *IO 40 *40 70 0 o< 10 4 .7 0 35589 DB87-011 32 < 63 11 75 0 o< 15 3 1 0 37032 88AP-ol/WAXO1 I< 35 114 0 00 24 63 2 47 1 35344 G3-3 *50 < 158 47 0 23 < 82 12 1.1 0 35345 G3-4 M<13 < 78 0 89 < 38 < < 0 33265 84AP-01 *52 0 0 0 0 0 00 0 < < 0 33266 84AP -01A *450 0 0 0 0 0 00 0 < < 0 30117 AP85-33-Ax2 < < 12 < 110 00 0 << 0 37035 88AP-04/09-AX05 1 c 177 6 76 0 0 0 *445 11 2 364

38431~~ ~ 88AP-26104-79-AX18 34805 DB87-037 *130 *30 <20 2.4 0 0 < 140 4 .5 0

148 Geological Survey Branch Ministry ofEmpIoymnt an,ilnvestmnl

(APPENDIX M continued) LAB FIELD Au Ag Cu Pb MoZn Ni Co Hg As SI) Ba

NO NO P6b ppb " 35346 G5-2 30 G5-235346 < 2366 12 0 20 <21 26 13 0 35347 G7-3 30 G7-335347 c 11 < 55 0 *360 <2 28 ': 0 35319C1-9 20 15 c 3 3803< < 4 <: 0 35298 C2-1 < .6 4*43 3 0 oc C 0 <: 0 35320(2-3 30 < 12 69 58 0 9 < 33 1 <: 0 35299 C2-4 c .5 220400< C 0 <: 0 35300 c2-11 <<3 2 30 o< 49 0 <: 0 35342C12-6 < 94c "28 38 0 3 c22 19 1.2 0 C8-2 4 *25 19 *25 4 35302 C8-2 << 0 0 < < 3 .5 0 35331C8-3 <<16 4 180

lJNlT8Nd MEAN c1

" Bulletin 97 149 British Columbia

150 Geo[ogica[SurveyBranch APPENDIX N ___.~ ASSAY SAMPLES (APPENDIXM) - LOCATIONS AND DESCRIPTIONS

L AB REC FIELDNUMREC LAB LATITUDELONGITUDE LoCATIONlAREANTSMAP MAP SAMPLE DESCRIPTION NUM NUM 0 t SI 0 , 11 UNIT

31617 I 85AP-20/12118-AX9 52-29-12.9 121-23-41.7 93N 6 1 1.8 km W of E tipHorsefly Peninsula pyrite with carbonale veinlets 32647 2 86AP-I4/IZAX3 52-24-11.2 121-16- 6.7 93N 6 1 1.5kmSofNikwitL carbonate alteration + quam veinlets 32649 3 86AP-2514-77-AXS 52-29-21.6 121-25-12.3 93N6 1 0.5 km E of W tip Horsefly Peninsula pyritic bleached mck 32651 4 86AP-2614-87-AX7 5228.33.3 121-20.49.1 93N6 I on S shore of Quesnel L quartz vein 34904 87AP-IU3-AX03 5 5224-47.7 121-34.48.3 93N5 I 1.7 km W of western tip Antoine L rusty, carbonate-altered veinlets 34907 6 87AP-1414-AXC6 52-24- .7 121-11- .8 93N 6 1 N shore Horsefly L, 3.5 km SSW grab sampover 1 m rusty zone of quam-ankerite ofViewland Mtn vein-brecciainfilling 34909 7 87AP-16/5-AX08 52-24-26.4 121-33-17.2 93N 5 1 1 km S western tip Antoine L pyrite-carbonate altered fault zone 34917 8 87AP-24/1-74-AX16 522346.7 121-3548.0 93AI 5 1 on Antoine Ck. 0.6 km NE Roben L pervasive carbonate-altered, fine-grained pyrite or (?) marcasite clots 37033 88AP-01/08-AXM 9 52-24-28.9 121-40-49.4 93N5 1 0.5 km N of McCauley L orange carbonate veins at basalt - argillite contact along fault 37385 IO 88AP-04105-AX03 52-21-27.1 121- 6-53.2 93N 6 1 2kmNWofHorseflyMtn calcite veinlets in shear zone with clay gouge 37034 11 88AP-04106-AX04 52-21-25.1 121-6.52.1 93N 6 1 2 km NW of Horsefly Mtn carbonalealtered. bleached, above shear mne 37036 I2 88AP-OS/OI-AX06 52-23-32.7 121-39-36.4 93N 5 I 1 km SE of McCauley L orange carbonate-altered. moderately fractured sandstone-conglomerate. Chip sample 37037 13 88AP-05/03-AX07 52-23- 4.5 121-40- 5.4 93N 5 1 2 km S of McCauley L pyrite carbonate veinlets + pervasive alteration 37038 14 88AP-07IlO-AX08 5226- .9 121-39- 7.4 93N 5 1 3.5 km SW of Moorhouse L pervasive orange carbonale-altered sandstone, trace pyrite 37043 15 88AP-13I07-AX12 52-28.21.6 121-43-40.5 93N 5 1 1.5 km S of Gavin L carbonate-altered fault (?) zone 37044 I6 88AP-15102-AXI3 52-29-37.3 121-47-28.9 93N 5 1 2.2 km W of Gavin L carbonate-allered pyroxene basalt 38432 17 88AP-26/13-AX19 52-26.34.7 121-7-34.5 93N 6 1 3 km NE of Viewlmd Mtn sheared, rusty, fine-grained sediments; large shear 38433 18 88AP-32JO7-AX20 52-28-24.8 121-16-42.4 93N6 1 3 kmNEofNiquidetL msty polylithic conglomerate with calcite veinlets 38526 19 88AP-11I06-37-AX21 52-26.44.0 121-48- 5.9 93N 5 1 I km SSE of Dorsey L on sulphides (pyrite and ?others) infeldspathic grit beds waterline road 35303 20 CIO-IB 52-58-14.6 122-18-51.9 938116 1 on Quesnel R. 3 km N of Deacon Ck red tuff 35335 21 CIO-IC 52-58-16.0 122-18-53.7 93B/16 1 on Quesnel R, 3 km N of Deacon Ck pyroxene-beaming wacke 35304 22 CIO-ID 52-58-17.2 122-18-55.2 93B/l6 1 on Quesnel R, 3 km N of Deacon Ck red tuff 35305 23 CIO-IE 52-58-18.6 1221846.2 93B/16 1 on Quesnel R, 3 km N of Deacon Ck altered zone 35306 24 C10-IF 52-58-19.8 122-18-56.8 938/16 1 on Quesnel R, 3 km N of Deacon Ck tuff 35307 25 CIO-ZD 52-58-25.5 12219- 1.3 938/16 I an Quesnel R, 3 km N of Deacon Ck argillite 35308 CIO-ZE26 5248-26.3 122-19- 1.8 938/16 I on Quesnel R, 3 km N of Deacon Ck tuffaceous wacke 35314 27 C13QB 52-55- 7.3 122-17-34.7 93B/16 I on Deacon Ck, 4km fmm Quesnel R altered basalt 35315 28 C13-4 52-55 8. I 122-17-34.3 938/16 1 on Quesnel R, between Vase and pyritic basalt Cantin Ck 35316 29 C13-6 52-55- 8.9 122-17-33.3 938116 1 on Quesnel R, between Vase and calcite vein in basalt CantinCk 35343 30 C13-7 5255-29.3 17217.25.9 93Rllh I on Qatesnel R;hetween Vase and hnealt with Iwd chlorite veinino Cantin Ck (APPENDIX N Continued)

LAB REC FIELDNUM LATITUDELONGITUDE NTSMAP MAP LOCATION/AREA SAMPLE DESCRIPTION NUMNUM 0 I ,, 0 , 1, UNIT

35317 31 Cl3-8B 52-55-39.3 122-17-37.7 93B/16 1 on Quesnel R, between Vase and chlorite & epidote altered basalt Cantin Ck 3491 I 32 87AP-18/11-AXIO 5219-17.6 121-31-27.9 93N5 2A on Gravel Ck, 7.5 km WSW of Horsefly carbonate-altered shear zone, sampled for Cu 37042 88AP-13/05-AXll33 52-28-13.6 121-44-37.2 . 93N5 2A 2 km S of Gavin L epidote-altered breccia matrix; chip sample 37045 34 88AP-17/04-AX14 52-28-53.6 121-46- .5 93N5 2A 1.4 km WSW of Gavin L carbonate-altered breccia, chlorite veining 37046 88KH-OU05-IA-AX9035 52-28-34.1 121-38-38.4 93N5 2A 3.3 km W of Edney L carbonate alteration + quartz veining 38428 36 88AP-2U05-AX15 52-19-48.1 121-10-12.3 93N6 2A 2 km N of Patenaude L NSty, limonite-altered with trace pyrite 38429 37 88AP-2UOS-AXI6 52-19-48.0 121-10-12.2 93N6 2A 2 km N of Patenaude L NSfy, limonitealtered with trace pyrite 38430 88AP-23/02-AXI738 52-19- 2.3 121-10-28.5 93N6 2A 0.5 km N of Patenaude L epidotized. sheared pyroxene basalt breccia 35336 39C10-3A 52-59-19.0 122-20-47.2 93B/16 2A on Quesnel R. 3 km NNW of Deacon Ck basalt 35337 40 CIO-3B 52-59-20.8 122-20-50.5 93B/16 2A on Quesnel R. 3 km NNW of Deacon Ck basalt, pyritic 35338 41 C10-3D 52-59-24.1 122-20-58.8 93B/16 2A on Quesnel R, 3 km NNW of Deacon Ck volcanic pyroxene-bearing wacke 35318 42 Cll-4 52-58-14.8 122-16-11.0 93B/16 2A on Deacon Ck, 4 km from Quesnel R basalt 31615 85AP-19/l-110-AX743 52-29- 8.9 121-24-49.1 93N6 2B 1 km SE of W tip of Horseflly Peninsula silicified breccia with pyrite in bleached volcanic 31616 44 85AP-l9/3-llOB-AX8 52-29-19.3 121-2434.3 93N6 2B I km E of W tip of Horsefly Peninsula soil 32048 86AP*9/4-37-AXI45 52-25-12.4 121-21-l6.4 93N6 26 2.3 km NW of Kwun L quartz gashes, chip sample 32049 46 86AP-lU5-48-AX2 52-24-36.0 121-21-32.3 93N6 26 2 km W KwunL sheared, carbonate altered 32648 4786AP-23/4-AX4 52-23-58.5 121-19-7.5 93N6 28 0.6 km S of Kwun L quam veinlets 32650 48 86AP-26/2-86-AX6 52-27-35.8 121-23-34.9 93N6 2B Horsefly R, I km upstream fmm very fine grained pyrite, trace chalcopyrite Quesnel L outlet 32652 86AP-38/1-145-AX849 52-23-44.4 121-20-23.8 93N6 28 0.8 km SW of Kwun L cinnabar with pyrite in quartz-carbonate veinlets 32653 50 86AP-41/1-16l-AX9 52-25-48.8 121-24-23.9 93N6 28 2.2 km SW of Hooker L carbate-altered fault zone 32654 51 86AP-4U2-165-AXIO 52-23-38.6 121-24-38.2 93N6 2B on Horsefly R, 0.8 km NE of Ratdam L quarlz-calcite drusy vein, (?)marcasite 34905 52 87AP-l3/2-AX04 52-23-41.7 121-24-47.2 93N6 2B on Horsefly R, 0.8 km NE of Ratdam L pervasive chlorite &carbonatealteration; grab sample 34906 53 87AP-13/3-AX05 52-23-45.0 121-24-59.4 93N 6 28 on Horsefly R, 0.8 km NE of Ratdam L quartz-calcite vein with NS~Ymargin 34914 5487AP-224-58-AX13 52-23-39.1 121-24-33.7 93N6 28 on Horsefly R, 0.8 km NE of Ratdam L vuggy calcite - chalcedony veinlets 34915 55 87AP-225-59-AX14 52-24-52.6 121-25-42.0 93N6 2B on Horsefly R, 3.5 km E of Antoine L carbonate and zeolite alteration in pyroxene basalt 34916 87AP-24/3-66-AX1556 52-24-36.4 121-25-52.9 93N6 28 on Horsefly R, 3.5 km ESE of Antoine L rusty fracturess with calcite, chlorite &epidote 34918 87AP-28/1-87-AX2357 52-21-38.4 121-21-18.0 93N6 26 2.5 km W of SW end of Horsefly L pervasive chlorite alteration epidote-calcite clots 37039 58 88AP-08/03-AX09 52-25-22.4 121-41-59.8 93N5 2B 3 km E of SE end George L epidotized patches in coatse breccia 37040 88AP-08/04-AX1059 52-25-33.7 121-42-32.4 93N5 2B 2.4 km ENE of SE end George L epidotized breccia 35325 60 C4-IO 52-53-18.0 122- 8-51.1 938116 28 headwaters of Cantin and Gerimi Cks basalt with minor pyrite 35301 61 C4-12 52-53-14.3 122- 8.43.7 936/16 28 headwaters of Cantin and Gerimi Cks disseminated pyrite in siltstone 35326 62C4-IZB 52-53-14.2 122- 8.44.7 93B/16 28 headwaters of Cantin and Gerimi Cks silicified basalt with Cu staining 35328 63 C6-2C 52-54- 9.5 122-11-52.0 93B/16 2B headwaters of Cantin and Gerimi Cks basalt 35329 64 C6-3A 52-53-54.7 122-11-44.1 93B/16 2B headwaters of Cantin and Gerimi Cks basalt 35330 65 C7-3 52-53.37.6 12210-33.0 93B/16 2B headwaters of Cantin and Gerimi Cks basalt 35312 66 CII-17 52-57-41.6 122-16.28.9 93B/16 2B on Deacon Ck. 4 km from Quesnel R epidotized basaltic breccia 35341 67 CII-19 52-57-39.9 122-16-30.2 93B/16 2B on Deacon Ck, 4 km from Quesnel R basaltic tuff (APPENDlX N Continued)

LAB REC FlELDNUM LATITUDELONGITUDE NTSMAP MAP LOCATION/AREA SAMPLE DESCRIPTION NLJM NUM 0 I 11 0 I ,I UNIT 31613 68 85AP-17/2.102-AX5 52-28- 6.2 121-27- .5 93N6 2E 4.3 km NE of Shiko L carbonate in limoniticshear 31614 6985AP-17I2-102AX6 52.28- 6.3 121-27- .5 93N 6 2E 4.3 km NE of Shiko L 34908 70 87AP-IWl-AXO7 52-23-56.1 121-3231.7 93N5 2E 2 km S of Antoine L epidotized analcite basaltbreccia 34910 87AP.411-AXW71 52-21-52.1 121-30-51.1 93N5 2E 2.5 km E ofjunaion of Gravel Ck road native Cu in amygdaloidal, analcitepyroxene basalt 34798 72 87AP-25n-AX17 52-23-31.0 121-33-42.5 93N 5 2E 2kmEofRobertL silicified, vuggy with pervasive chalcedony and some carbonatealteration 34799 73 87AP-2512.AX18 52-23-31.0 121-33-42.5 93N 5 2E 2 km E of Robert L peripheral to AX17 grab over 30 m of carbonate altered volcanic breccia 34800 87AP-2616-AX1974 52-23-31.4 121-33-55.4 93N5 2E 2kmEofRobertL pervasive carbonate alteration 34801 87AP-26fl.AX2075 52-23-28.4 121-33-55.1 93N5 2E 2 km E of Robert L random grab over30 m ofvuggy, silicified amygdaloidal pyroxene basaltbreccia 34802 76 87AP-26fl-AX21 52-23-28.4 121-33-55.1 93N 5 2E 2kmEofRobeRL grab sampleover 20 m ofcsrbonate-silica altered rock 34803 77 87AP-ZW-AX22 52-23-28.4 121-33-55.2 93N5 2E ZkmEofRobertL grab over 20 m of carbonate-silica altered rmk 30118 78 AP85-65-AX3 52-27-22.2 121-27dS.l 93N 6 20 Shiko L pyrite and epidotein pyroxene-plagioclase basalt 30119 79AP85-66-AX4 5227-38.0 121-27-57.9 93N6 20 Shiko L epidote-altered pyroxene-plagioclase basalt 301 16 80 AP85-14-AXI 52-54-16.0 122-22-30.6 938116 2H Dragon Mm rusty, leached quaiz-calcite veinlets 37041 88AP-l2/01-38-AXlOA81 52-26-21.0 121-47-16.1 93N5 2H 0.5 km SE ofBeaver L pervasive carbonate alteration, calciteveinlets 34902 82 87AP-811-AXOI 52-19- 9.9 121-26-26.3 93N 6 3 1 km ENE of China Cabin L carbonate veinletsin lahar 34912 87AP-21/9-55-AXll83 52-23-20.3 121-30-54.4 93N5 3 3 km S of Antoine L rusty fragmented basalt with limestone clasts 34913 87AP-ZZ/1-57-AX1284 52-20.5.9 121-28- 7.4 93N 6 3 4.5 km W of Horsefly village malachite-staind lahar and sandstone debris 35321 85 C3-3 52-55-13.9 122-12-51.1 938116 3A headwaters of Cantin and Gerimi Cks altered basalt with trace ..write 35322 86C3-4 52-55- 6.8 122-13-.4 938116 3A headwaters of Cantin and Gerimi Cks basalt 35323 87 C3-IO 52-55- 7.5 122-12-40.5 93B116 3A headwaters of Cantin and Gerimi Cks basalt. localllv with ..vyriteincalcite veins 35324 88 GI-ZC 52-54-14.6 122.10. 2.1 938116 3A headwaters of Cantin and Gerimi Cks basaltic breccia 35309 89 Cll-8A 52-58- 6.3 122-16-12.9 938116 3A on Deacon Ck, 4 km from Quesnel R gabbro? dark green, come grained 35339 90 CII-9 52-58- 1.7 122-16-13.2 938116 3A on Deacon Ck. 4 km from Quesnel R basalt 35310 91 CII-IO 52-57-57.2 122-16-16.9 938116 3A on Deacon Ck, 4km from Quesnel R epidotized basalt 35340 92 CII-ll 52-57-55.5 122-16-18.9 938116 3A on Deacon Ck, 4 km from Qnesnel R bash 3531 I 93 Cll-12 52-57-53.6 122-16-20.3 938116 3A on Deacon Ck, 4 km from Quesnel R altered baslt 35313 94 Cll-I3 5257-51.0 122-16-20.8 938116 3A on Deacon Ck, 4 km from Quesnel R epidotized wacke 35344 95 G3-3 52-54-33.8 122-10-10.9 938116 3A headwaters of Cantin and Gerimi Cks syenite 35345 96G3-4 52-54-33.8 122-10-10.9 938116 3A headwaters of Cantin and Gerimi Cks pyroxenite 35348 91 08-1 52-54-25.6 122- 9-59.1 938116 3A headwaters of Cantin and Gerimi Ckr basalt porphyry 35349 98 GB-3 52-54-25.6 lU- 9-59.1 938116 3A headwaters of Cantin and Gerimi Cks basaltic tuff 35350 99G8-4 52-54-25.7 122-9-59.1 93B116 3A headwaters of Cantin and GerimiCks basaltic porphyry 34903 100 87AP-814-AX02 52-19-15.8 121-27- 7.4 93N 6 4 0.5 km N of China CabinL carbonate alteration- minor veins, mainly pervasive 34804 101 DB87-010 52-36-31.4 121-40.41.1 93N12 4 hior L epidote-altered matrixof basil breccia 35589 102 DB87-011 52-36-31.4 121-40-41.3 93N12 grey basalt 37032 103 88AP-01104AXflI 5?.7A. !.a !2!-?5-??.! ?'?.2/C caicite veins (APPENDIX N Continued)

LAB REC FlELDNUM LATITUDELONGITUDE NTSMAP MAP LOCATION/AREA SAMPLE DESCRlPTlON NUM NUM 0 I ,I 0 I 9, UNIT

33265 104 84AP-01 52-39-29.1 121-47-58.6 93Nl2 7 QR deposit trench propylitic basalt ~ weakly altered, minor pyrite

33266 105 84AP-01A 52-39-29.1 12147-58.6 93N12 7 QR deposit trench propylitic basalt ~ intensly altered, abundant pyrite 301 17 106 AP85-33-AX2 5237-32.4 121-38- 5.0 93N12 7 Bullion Pit talus chips fromdense, slightlyrusty rocks 37035 107 88AP-M/09-AXO5 52-21-24.3 121- 5-52.6 93N6 7 1.2 km NNW of Horsefly Mtn cabonate-altered chloritized diorite in faultzone 38431 108 88AP-26/04-79-AX18 5225-36.9 121- 4-50.4 93N6 7 4.5 km N of Hom Bluff (Horsefly L) weak silicification, blebby pyrite in diorite dike 34805 109 DB87-037 52-39-41.5 121-45-20.9 93N12 7 on Quesnel R, 2.8 km E of QR deposit calcite vein 35346 110 05-2 52-54-37.4 122-10-24.1 938136 7A headwaters of Cantin and Gerimi Cks altered basalt 35347 I11 07-3 52-54-55.2 122-11-12.2 936116 7A headwaters of Cantin and Gerimi Cks pyroxenite 35319 112 c1-9 52-58- 5.7 122-11-41.8 938116 7B headwaters of Deacon and Cantin Cks syenite porphyrywith sparse pyrite 35298 I13 CZ-1 52-57-34.9 122-11-47.3 936116 78 headwaters of Deacon and Cantin Cks quam vein 35320 114 CZ-3 52-57-37.4 122-11-45.7 938116 78 headwaters of Deacon and Cantin Cks syenite porphyry cutby K-feldspar veins 35299 115 '2-4 52-57-39.4 122-11-47.1 938116 78 headwaters of Deacon and Cantin Cb quartz vein 35300 116 C2-I1 52-57-37.3 122-10-55.7 936116 78 headwaters of Deacon and Cantin Cks quartz vein 35342 117 C12-6 52-56-17.3 122-12-36.7 936116 78 hadwaters of Cantin and Gerimi Cks syenite porphyry 35302 118 C8-2 52-53-43.3 122-l6.41.1 936116 8 on Quesnel R, 2 km S of Cantin Ck altered grmite 35331 119 C8-3 52-54-17.9 122-16-38.9 938116 8 on Quesnel R, 2 km S of Cantin Ck basaltic tuff 35332 120 C8-6 52-54-34.8 122-17-10.4 938116 8 on Quesnel R,2 km S of Cantin Ck granite 35333 121 C8-7c 52-54-35.0 122-16-54.7 938116 8 on Quesnel R, 2 km S of Cantin Ck volcanic-source, pyroxene-bearing wacke 35334 122 C8-7K 52-54-35.1 122-16-54.9 938136 8 on Quesnel R, 2 km S of Cantin Ck granite porphyry 34919 123 87AP-323-98-AX24 52-29-38.3 121-30-51.8 93N5 9A/B 1.6 km W of Hazeltine R, Quesnel L rnsty fractures, minor chalcedony and calcite in feldspar crystal ash tuff 34920 124 87AP-325-AX25 52-29-58.1 121-31-9.9 93N5 9A/8 1.6 km W of Hazeltine Pi, Quesnel L msty orange carbonate and vuggy chalcedony-quam veinlets, in Tertiary conglomerate 35327 125 C5-2 52-56-7.0 122-14-355 93B1L6 TILL headwaters of Cantin and Gerimi Cks altered basalt ~~ ~ ___.

Ministry of Employmenr and Investment "

APPENDIX 0 PLA-, PALLADIUM AND GOLD ANALYSES " LAB FIELD Pt Pd Au NO NO (ppb) (ppb) (ppb) 32365 84AP-1 4.3 6.2 15.9 33266 84AP-1A < 3.8 16.9 31597 85AP-111-35A 5.0 7.1 8.0 31559 85AP-518-56A 11.813.2 9.9 31601 85AP-7/2-63 3.2 6.1 3.0 31603 85AP-8/6-67 < < < 31605 AP85-8/2-69 7.212.0 1.0 31606 AP85-8/9-71 < < 3 31609 85AP-2012-115 6.1 2.4 < 31610 85AP-21/2-120 < < 2.7 32050 86AP-4/6-18 < 2.024.4 32051 86AP-4/6-26 4.8 6.6 1.8 32052 86AP-6/10-29 1.8 19.3 2.1 32053 86AP-10/8-44 3.3 21.2 2.3 32054 86AP-13/3-51 4.9 17.8 1.9 32641 86AP-21/4-66 4.0 11.3 17.7 32642 86AP-28/4-92 < 9.3 10.1 32643 86~~-28n-98 6.4 . 10.3 3.8 3479981AP-25/2-AX18 < 2.6 8.8 35319C1-9 < < < 35320C2-3 < 1.1 8.0 35328C6-2C 5.8 5.1 7.6 35329C6-3A 3.0 4.3 < 35330 0-3 1.2 8.9 2.4 35331C8-3 < < < 35332C8-6 < < < 35339 Cll-9 5.21.7 8.1 35340 c11-11 1.6 3.9 7.1 35343 C13-7 < < < 35345 G3-4 1.7 2.7 11.4 35341 G1-3 2.3 26.3 2.1 35348G8-1 11.0 4.8 8.6 35350 G8-4 11.1 4.6 8.8 35797 MB-15 5.0 5.1 < 35798 MB-02 11.013.5 < 35799 MB-16 5.9 3.5 < 35800 MB-05 1.0 9.7 < 35801 MB-185 10.0 14.6 < 35802 MB-219 9.0 5.4 1.0 35803 MB-269 1.2 5.6 7.1 35804MB-274 11.34.6 < 35805 MB-358A < 5.3 < 35806 MB-172 9.1 5.7 < 35807 MB-395 9.1 5.7 < 35808 MB-374 4.9 2.4 < 35809 MB-409 1.7 11.7 2.3 35810 63310A 4.0 8.8 1.0 35811 63310B < < <

35812~ ~~~ 86MB-20 64.9 < 1.4.. ~ below detection limit indicated by< Collector code:A. Panteleyev - AP; J. Lu - c; M.A. Bloodgood - others

" Bulletin 97 155 Britkh Columbia

I56 Geological Survey Branch