Stratigraphy of the Project Area

I BRITISH &! COLUMBLA Ministry of Employment and Investment ENERGY AND MINERALS DIVISION Hon. Dan Miller. Minister Geological Survey Branch

THE STIKINE PROJECT GEOLOGY OF WESTERN TELEGRAPH CREEK MAP AREA, NORTHWESTERN BRITISH COLUMBIA (NTS 104G/5,6, llW, 12 AND 13)

By Derek A. Brown1 , Michael H. Gunning2 and Charles J. Greig3

Appendix 3 - Conodont identifications by "I. Orchard, Geological Survey of Canada 1. Geological Surve Branch, British Colunlhia Ministry of Employment andYlnvestment 2. Department of Geology, University of Western Ontario, London, Ontario 3. C.G. Greig and Associates Ltd., Penticton, B.C.

BULLETIN 95 Canadian Cataloguing in Publication Data Brawn. Derek Anlhony. 1959- The Stikine project : geology of western Telegraph Creek map area. nonhwenlem British Columbia (NTS.lMG15. 6, IIW. 12and 13)

Issued by Geological Survey Branch. Includes bibliographical references: p ISBN 0-7726-2502-6

1, Geology -British Columbia -Telegraph Creek Region 2. Geochemistry - British Columbia - Telegraph Creek VICTORIA Region. 3. Geology. Economic - British Columbia - BRITISH COLUMBIA Telegraph Creek Region. 4. Mines and mineral resources - CANADA British Columbia - Telegraph Creek Region. 1. Gunning. Michael H. 11. Greig.Charles James, 1956- . 111. British Columbia.Ministry of Employmentand Investmenl. IV. MAY 1996 BritishColumbia. Geological Survey Branch. V. Title. VI. Title: Geology of western Telegraph Creek maparea, nanhwertern British Columbia (NTS 1WG15.6. 1 IW. 12 and 13). V11. Series: Bulletin (British Columbia. Ministry of Employment and Investment) ;95.

QE187.B76 1996 557.11’185 (395-960208-9 Frontispiece. View north along the Scud Glacier. Ambition Mountainis underlain by Permian limestone and metavolcanic rocks. Ministry of Emp/oyment and Inveshent

TABLE OF CONTENTS

CHAPTER 1 Chemistry ...... 45 INTRODUCTION ...... 1 ContactRelationships ...... 45 Location. Access and Physiography ...... Correlation and1 Age ...... 47 AboriginalFeatures ...... 2 EnvironmentDepositional ...... 47 Previous Work ...... 2 Eocene Sloko Group ...... 47 ExplorationHistory ...... 4 Chemistry ...... 48 Acknowledgments ...... Correlation and4 Age ...... 51 D epositional Environment 51 Environment Depositional ...... CHAFER 2 Miocene Or YounEer. (?) Flows ...... 51 I&GIONAL TECTONIC SETTING AND chemistry ...... 51 STRATlGRAPHY ...... 7 Age and Correlation ...... 51 Regional Tectonic Setting ...... 7 Quaternary ...... 51 Stratigraphy of the Project Area ...... 7 CHAPTER 3 Paleozoic Stikine Assemblage ...... 7 INTRUSIVE ROCKS 53 UpperCarboniferous Strata ...... :.. 9 Devils Elbow Unit ...... 9 Regional Overview ...... 53 ButterflyUnit ...... I1 Middle(?).. to Late Triassic Plutons(228-220 Ma) 55 Chutine River Area ...... 13 Alaskan-type Ultramafites ...... 55 Baninnton River andLink Tahltan Lake Mount Hickman Complex ...... 57 I Areas ...... 13 Middle Scud Ultramafite ...... 57 U~wr.. Carboniferous to Lower Permian Strata ... 14 Yehiniko Ultramafite ...... 57 Navo Formation ...... 14 Hickman Batholith ...... 57 Lower to Upper PermianStrata ...... 15 Hickman Pluton ...... 57 AmbitionFormation ...... 15 Nightout Pluton...... 58 ScudGlacier Formation ...... 17 Other Stikine Suite Plutons...... 58 RegionalCorrelations ...... 17 Late Triassic to Early Jurassic- Copper Paleoenvironmental Interpretation ...... 17 Mountain Plutonic Suite (210-195 Ma) ...... 59 Early Permianto Middle Triassic WimpsonUnit .... 18 ButterflyPluton ...... 59 Permo-Triassic Contact Relationships ...... 19 RuggedMountain Pluton ...... 59 Northeast of Devils Elbow Mountain ...... 20 ClinopyroxenitePhase ...... 61 Toe of Scud Glacier ...... 20 Syenite Phase ...... 61 South of Scud Glacier ...... 20 Hybrid Phase ...... 61 North of the ChutineCulmination the of North ...... 20 Alkaline Dike Swarm...... 61 Upper Triassic or Older Mafic Metavolcanic Rocks . . 20 Latimer Lake and Damnation Plutons...... 61 Upper Triassic Stuhini Group ...... 20 Early Jurassic Texas Creek Plutonic Camian to Lower Norian: Kitchener Unit ..... 21 Suite(189-195 Ma) ...... 62 Limestone Horiwns ...... 26 LimpokePluton ...... 62 Volcanic Facies Volcanic ...... 27 Pogue and Brewery Plutons...... 62 MaficVolcanic Rocks ...... 27 Pereleshin and Oksa Creek Plutons ...... 62 IntermediateVolcanic Rocks ...... 27 Early Jurassic(?) Diorite Intrusions ...... 63 TuffaceousWacke ...... 27 Late Eariy Jurassic Cone Mountain Intrusions Bladed-plagioclasePorphyry ...... 27 (187-180Ma) ...... 63 UpperNorian: Quattrin Unit ...... 28 Middle Jurassic Three Sisters Plutonic Chemistry and Tectonic Settingof the Stuhini Suite (177-170 Ma) ...... 64 Group...... 30 YehinikoPluton ...... 64 Depsitional Environments ...... 33 NikoPluton ...... 64 LowerMiddleto Jurassic Hazelton Group ...... 33 SaffronPluton ...... 64 Dacite Unit ...... 34 ConoverPluton ...... 64 LimyWacke ...... 35 Middle Jurassic Dike Swarms andDok Stocks ... 65 Andesite Flows andTuff ...... 35 Eocene Hyder Plutonic Suite (55-51 Ma) ...... 65 Rhyolite ...... 37 ChristinaPluton ...... 65 Basalt ...... 37 SawbackPluton ...... 65 Chemistry ...... 38 Hamper Pluton ...... 66 Contact Relationships between Jurassicand Oksa Creek Dike Swarm ...... 66 Triassic Units ...... 39 Tertiary(?) Granodiorite ...... 67 Age and Correlation ...... 39 Late Miocene (?)or Younger Dikes ...... 67 Depositional EnvironmentDepositional ...... 41 Geochemistry and Tectonic Discrimination of UpperCretaceous(?) to PaleoceneSustut Group .... 41 Intrusive Rocks ...... 68

... Bullelin 95 Ill British Columbia

Middle to Late Triassic ...... 68 Galore Creek ...... 106 Alaskan-typeUltramafic Plutons ...... 68 RuggedMountain Pluton ...... 106 StikineSuite ...... 70Pluton Limpoke ...... 106 Late Triassicto Early Jurassic Alkaline and MolybdenumDepositsPorphyry ...... 106 U lnamafi~c Plutons Ulnamafi~c ...... 70 AreaBenCreek .Deeker ...... 106 Creek Suite Texas Creek ...... 70 MesothermalTransitionaland VeinDeposits ..... 106 ConeMountain Suite ...... 70 Early To Middle Jurassic ...... 107 ThreeSisters Suite ...... 70 Yehiniko Fault Zone ...... 107 HyderSuite ...... 70 Northofthe StrataGlacierPluton ...... 107 Tectonic Discrimination...... 76 HelvekerCreek ...... 107 LateTriassic ...... 76 Conover Creek ...... 107 EarlyJurassic ...... 76 Scud Glacier Area ...... 110 MiddleJurassic ...... 76 Area GlacierLimpoke ...... 110 Eocene ...... 76 Eocene ...... 110 Temporal Evolution of Plutons: the Orogenic Pendants in the Strata Glacier Pluton .... 110 Cycle ...... 76 North of the Strata Mountain Pluton ..... 110 Epithermal Vein Deposits ...... 111 CHAPTER 4 VolcanogenicMassive Sulphide Deposits ...... 111 STRUCKIREAND METAMORPHISM ...... 77 Skam Deposits ...... 111 Tahltan Lake ...... 111 Pre-lateTriassic Deformation ...... 78 Devil's Elbow ...... 111 PhyllosilicateFoliation ...... 81 Scud River ...... 111 Developmentof Structural Culminations ..... 81 Other Deposit Types ...... 113 Little Tahltan Lake Culmination ...... 81 PlacerGold ...... 113 Barrington River Culmination ...... 81 StrataboundUranium ...... 113 ChutineRiver Culmination ...... 81 Cumulate Magnetite ...... 113 AgeConstraintsandTahltanianOrogeny ... 82 Zming of Regional Metallogenic Events ...... 113 Post-Norian and Pre-Toarcian Contraction of Stuhini Paleozoic: Volcanogenic Massive Sulphide Group ...... 84 Deposits ...... 113 AgeConstraints ...... 86 Late Triassic to Jurassic Porphyry Deposits and Structures near Scud Glacier Scud nearStructures ...... 86 Transitional to Epithermal Veins ...... 113 MiddleJurassicCretaceous or Contraction ...... 86 Early To Middle Jurassic: Volcanogenic Massive Folds ...... 114 86Deposits Sulphide ...... ContractionalFaults ...... 88 Middle Jurassic: Calcalkaline Porphyry Deposits ConeMountain Fault ...... 114 88 VeinsTransitional and ...... Butterfly Lake and Related Faults ...... 89 Eocene: Epithermal to Transitional Veins. N avo Shear Zone Shear Navo ...... 89 Porphyry Molybdenum-copper Deposits ...114 A ge Constraints Age ...... 89 Galena-Lead Isotope Results ...... 114 R egional Correlation Regional ...... 92 Exploration Activity ...... 115 Faults ...... Mineral Potential92 ...... 115 North-trending Faulb ...... 92 Scud Glacier Fault ...... 92 CHAPTER 6 Middle Scud Creek Faults ...... 93 SUMMARY AND CONCLUSIONS ...... 117 Oksa CreekDike Swarm ...... 93 Plutonism ...... 118 East-TrendingFaults ...... 93 Structure ...... 118 K itchener Fault Zone Fault Kitchener ...... 93 Metamorphism ...... 119 BoomerangRelatedFaults and 119 ...... Geology 93 Economic ...... DuctileFabrics ...... 93 TectonicModel ...... 120 JimjackFault System ...... 93 Northwest-trendingFaults ...... 95 REFERENCES ...... 121 Metamorphism ...... 95 ConodontColour Alteration Indices ...... 95 APPENDICES ...... 131 Late Permian to Early Triassic(?) Metamorphism . 95 1 . Macrofossil Identifications ...... 132 Jurassicto Prelate CretaceousMetamorphism 97 ... 2. Fusulinid Age Determinations ...... 135 EoceneBurial Metamorphism ...... Conodont 97 3 Identifications ...... 137 ContactMetamorphism 97 ...... 139 Collections Conodont 4 . Barren Summary of Metamorphism ...... 98 ...... 5 . Radiolarian Age Determinations ...... 141 CHAPTER 5 6 . Samples Barren of Radiolaria ...... 143 ECONOMICGEOLOGY ...... 99 7 . Palynomorph Collections ...... 145 PorphyryDeposits ...... 99 8. Whole-rock and Trace Element Chemistry of Stratified Calcalkaline Porphyry Copper Deposits ...... 99 Rocks ...... 147 SchaftCreek (Liard Copper) ...... Filtering 99 9 . of GeochemicalData ...... 155 Showings near Schaft Creek157...... 105Notes IO . Petrographic ...... Dokdaon - Strata AreaCreek ...... 105 11 . Whole-rock Lithogeochemical Analysesof Plutonic A lkalic PorphyryAlkalicDepositsCopper ...... 105 Rocks ...... 161

iV Geological Survey Branch Ministv of Employment and Investment

12 .Potassium-argon Analytical Data and Dates for Stratified 3.13 . Chemical characteristics of the Middle Jurassic Three andPlutonic Rocks ...... 169 Sisterssuite ...... 13 13. Uranium-Lead Analytical Data ...... 171 3.14 . Chemical characteristics of the Eocene Hyder suite . . 74 I4. Lithogeochemical Data ...... 173 3.15 .Tectonic discrimination diagrams for plutonic rocks. . 75 4- 1 . Distribution of major faults in nonhwestern British HGURES Columbia ...... 17 1- 1. Location map for the Stikine project ...... I 4- 2 .Major structural elementsin the Stikine project area . . 19 1- 2 . Physiographic regionsof the Telegraph Creek map 4- 3 .Cross-section illustrating deformedNorian clastic rocks area ...... 2 unconformably overlain by Toarcian flows and tuffs . . 85 1-Geographic 3 . features referred thetextin 3to ...... 4- 4 .Cross-section illustrating the contrastin deformation 2- 1. Locationof project area on asimplified terrane map 8 ... between Navo formation and overlying Ambition 2- 2 . Schematic stratigraphic succession ...... 9 Formation and the series of northwest-trending reverse 2- 3. Distribution of Paleozoic Stikine assemblage ...... 10 faults ...... 87 2- 4 . Stratigraphic column and paleoenvironmental 4- 5. Relationship of the Cone Mountainfault to the pluton interpretations for the Stikine assemblage ...... 11 hangingwallassemblageStikine88 and ...... 2- 5 . Stratigraphic column near the Scud Glacier...... 18 4- 6. Microfahrics associated with the Scud Glacier fault . . 92 2- 6. Distribution of enigmatic mafic metavolcanic rocks . . 21 4- 7 .Cross-sectionsof the Sustut Group ...... 94 2- 7. Distribution of the Upper Triassic Stuhini Group ... 22 4- 8 . Distribution of Sustut Group in the Yehiniko valley . . 94 2- 8. Schematic Stubini Group stratigraphic columns .... 23 4- 9 . Metamorphic facies smctural features and plutons ...96 2- 9 . Schematic Stuhini Group column nearSmta Creek . . 29 4-1O.Thermal maturation based on conodont colour alteration 2-10 . Major element geochemical plots for Stuhini Group.97 . 31metamorphic grade and indices ...... 2-1 1. Trace element diagrams for Stuhini Group...... 32 4-11.Histograms illusvating the distribution of CAI values 2-12. Distribution of Hazelton Group ...... 33determinations agetheir relativeto ...... 95 2-13. Schematic stratigraphic columnof the Hazelton 5- 1 . Major mineral deposits. mines and past producers Group ...... Tulsequah34 and Stewart between ...... 99 2-14 . Major and trace element geochemical plots for 5- 2. Mineraloccurrences in projectthe area ...... 100 Hazelton Group volcanic rocks ...... 36 5- 3. Galena-lead isotope signatures for mineral showings . 114 2-15 . Unconformable relationships between the Upper Triassic 6.1 . Schematictectonic evolution ...... 117 Stuhini Group, Jurassic Hazelton Group and Upper 6.2 . Schematic Mesozoic tectonic evolution ...... 119 Cretaceous to Paleocene Sustut Group, and their relation 6-3 . Schematic Cretaceous and Eocene tectonic framework to theLate Triassic and Middle Jurassic plutons 40 .... fornorthern Cordillera ...... 120 2-16. Distribution of Sustut Group, paleocurrent directions and age consmints ...... 43 PHOTOS 2-17 . Sketch of key exposure of the SUSIUI Group...... 44 Frontispiece. View north along the Scud Glacier 2-18 . Major and trace element geochemical plots for Sustut I- 1. Stone cairn above the Stikine River ...... 4 Group, Sloko Group and Miocene(?) volcanic rocks. . 46 I- 2. Obsidian flakes collected above Barrington River 2-19. Distribution of Sloko volcanic rocks ...... 48 valley ...... 5 2-20. Sloko Group stratigraphic column ...... 48 2- 1. Volcanic breccia of the Stikine assemblage...... 12 3- 1. Distribution of plutonic rocks, and majorore deposits 2- 2 .Pillow with intrapillow micrite ...... 14 between Stewart and Dease Lake 53 Lake Dease andbetweenStewart ...... 2- 3 .Reworked felsictuff (Navo formation) ...... 15 3- Distribution2 . of plutons in theproject area 55 ...... 2- 4 .Argillaceous limestone and limestone ...... 16 3- 3. Distribution of the Middle to Late Triassic Stikine and 2- 5 .Limestonewith chen layers and lenses ...... 16 Mount Hickman Plutonic Suites ...... 55 2- 6 .Ribbon chen ...... 19 3- 4 . Distribution of the Late Triassicto Early Jurassic 2- 7. Microfabrics of the Stuhini Group ...... 24 CopperMountain Plutonic Suite ...... 59 2- 8. Sedimentary st~cturesin Upper Triassic tuffs .....25 3- 5. Biotite "Ad9Ar plateau date for the Rugged Mountain 2- 9 . Carnian limestone cliffs southwest ofTahlm Lake ... 26 ~~ pluton ...... 2.10 . Heterolithic61 breccia with volcanic and plutonic clasts . 26 3- 6 .Distribution ofEarlv Jurassic Texas Creek Plutonic 2-1 1. Angular limestone boulder in volcanic conglomerate . 28 and Early Jurassic diorites 62dioritesJurassic SuiteEarly and ...... 2.12 . Dacitic lapilli tuff and ash-tuff beds ...... 28 3- 7. Distribution of late Early Jurassic Cone Mountain 2.13 . Heterolithic breccia composed of volcanic and plutonic Plutonic Suite ...... 63 fragments ...... 29 3- 8. Distribution of Middle Jurassic Three Sisters Plutonic 2.14 . Unconformable contact of Stuhini Group sedimentary Suite ...... 64 rocks with Jurassic volcanic rocks ...... 30 3- 9 . Distribution of Eocene Hyder Plutonic Suite ...... 65 2.15 . Angular unconformity separating Stuhini Group from 3.10 .Chemical characteristicsof the Stikine suite compared HazeltonGroup ...... 35 w ith the Alaskan-typeultramafites 69the with ...... 2.16 . Stuhini Group overlain unconformably hy Jurassic 3.11 . Chemical characteristicsof the Rugged Mountain flows ...... 37 Complex ...... 2.17 .Jurassic lithic71 lapilli tuff ...... 38 3.12 . Chemical characteristicsof the Early Jurassic Texas 2.18 . Flat-lyinglava flows of theJurassic succession 38 .... Creek and late Early Jurassic Cone Mountain suites . . 72 2.19 . Basaltfragment displaying breadsrust texture39 .... 2.20 . Lower Jurassic tuff-breccia north of Helveker Creek . 40

. Bulletin 95 V British Columbia

2.21 . SusNt Group conglomerate unconformably deposited 4.12 .Photomicrographs comparingundeformed and mylonitic on altered Jurassic volcanic rocks ...... 41 Cone Mountainpluton ...... 90 2.22 .lLpical conglomerates of the SusNt Group ...... 43 4-13. Mylonitic contact of the Butterfly syenite and 2.23 . mew southeast to SusNt Group conglomerate .... 44 Carboniferousvolcanic rocks (Butterflyformation) . 91 2.24 . Sloko volcanic rocks ...... 46 4.14 .Brecciated dikesand diorite within mylonitic 2.25 . Trachyandesite flowsof the Sloko Group ...... 49 diorite ...... 91 2.26 . Andesitic crystal lithic lapilli Nff-breccia ...... 50 5- 1 . Aerial view of propylitic alteration zone at Ben 2.27 .Flat.lying. columnar jointed basalt flow...... 50 Mo-Cu-W prospect ...... 107 3- 1. Rugged Mountain syenite complex ...... 60 5- 2. Vein texmres from Deeker Creek...... 108 3- 2. Megacrystic dieof Rugged Mountain 5- 3. Vein textures from Chuckter showing ...... 108 complex ...... 60 5- 4 . Multiphase veins ...... 109 3- 3. Breccia zone with Jurassic diorite and granodiorite 5- 5 .Quartz .iron carbonate breccia zone ...... 110 inclusions hosted by Eocenegraniteinclusions byhosted ...... 66 5- 6. Iron-carbonate quam vein ...... 112 3- 4. SawbackEoceneplutongranite ...... 67 3- 5 . phyllite xenolith within the Geology Ridge diorite . . 68 TABLES 4- 1 . Deformation in Tahltan Lake structural 2- 1. U-Pb and K-AI Isotopic Dates for Stratified Rocks . . 12 culmination ...... 80 3- 1. Characteristics of the Intmsive Rocks ...... 54 4-2 .Microfabrics in theBarrington River culmination ... 82 3- 2 . Summary of U.Pb. K-Ar and AI-AI Datesfor Plutonic 4- 3 .Vlew uortbwest to the Ugly anticline ...... 83 Rocks ...... 56 4- 4 .Chevron-folded Middle Triassicchen ...... 83 4- 1 . Summary of Structural Features ...... 78 4- 5. Txght folds of mafic schistin a pendant within the Early 5- 1. Summary of Mineral Occurrence Characteristics.... 101 JurassicGeology Ridge diorite ...... 84 5- 2 . Summary of Deposit Types and PotentialSettings ...115 4- 6 . StrucNral discordance between Norian sedimentary rocks and Hazelton volcanic rocks ...... 85 MAP 4- 7. Chevron-folded metavolcanic rocks (Stuhini Group?) 86 Geology Map of western Telegraph Creek map area(104G6.6. 4- 8. Steeplydipping foliation in the ScudRiver valley ... 87 11W. 12 and 13) 1:lOO OOO scale. including schematic cross-sec- 4- 9. Bedding-cleavageintersgtions felsic in tuff ...... 87 tions of westem Telegraph Creek map area(104G15.6.11W. 12 4-10.Asymmetric. southwest-verging fold in limestone . . 88 and 13) 1.100000scale ...... inpocket 4.11 .Minor folds in foliated Iuffaceous rocks (Butterfly member) ...... 89

vi Geological Survey Branch CHAPTER 1 INTRODUCTION

The Stikine project area, approximately 50 kilometres LOCATION, ACCESS !southwestof Telegraph Creek, lies astridethe Stikine River, AND PHYSIOGRAPHY ;I major tsansportationmute much used by prospectors. The ]projectarea covers partof a northwest-trending mineral-rich The Stikine projectarea islocatedin northwestemBrit- 'belt that includes important precious and metal base deposits ish Columbia, approximately 400 kilometres northwest of :such as Premier, Creek, Johnny Moun- Smithers and125 kilometres southwestof kse Lake. The Sulphurets, Eskay closest supply and service centreis Telegraph a vil- .tain, Snip, GaloreCreek andGolden Bear (Figure 1-1). and Creek, 'was selected for study due to its high mineral potential but lage of a few hundred people50 kilometres tothe northeast. *outdatedgeological database. This report synthesizes and Regular airand buck services to Telegraph Creek andkse .reviews previous geologicalwork, provides new data on Pa- Lake operate throughout the summer months. A rough leozoic and Mesozoic stratigraphy, and describes Mesozoicgravel road provides four-wheel-drive access from Tele- plutonic suites and mineral occurrences. graph Creek to part of the northwest comer of the project

134' 132' 130

StikineProject ~ Geosclence Maps1993-3 to 1593-6 /Bradford and Brown (19931 m~oganet a1 (1590. 1992) Loganand Koyanagi (1989) =Read (1983.1984) mReadet al (1589) Gabrielse (19801

x Mlne or DevelopeC prospect

0 km 50

134' 130'

Figure 1-1. Location map showing previous geological mappingin Telegraph Creek map area and environs.

Bulletin 95 1 area, but practical access to most ofarea the is by helicopter. HISTORICAL FEATURES Gravel airstrips are located at the confluence of the Scud More than fifty stone cairns are distributed along the and Stikine rivers,at Schaft Creekand near themouth of the Stikine valley, near themouth of the Scud River (Figure1-3; Barrington River (Figure 1-2b). Photo 1- 1). The cairns are completely coveredby lichen and The map area covers partsof two broad physiographic moss and varyin shape; some are domaland others rectan- regions, the Coast Mountains (Boundary Ranges) on the gular. Their average height is approximately 1 metre and southwest and the Tahltan Highlandson the northeast (Hol- circular ones areabout 2 metresin diameter. All are builton land, 1976; Figure Ma), which were further subdividedby prominent knolls. between 1100 and 1350 metres elevation, Ryder (1984; Figure 1-2b) into Telegraph Creek lowlands overlooking the StikineRiver. They were first describedby and Zagoddetchino and Tahltan Lake plateaus. The Coast Kerr (1948a); however, little is known of them except that Mountains comprise 75% ofthe area, andare characterized they were builtin the territory occupiedby both ancient in- by steep, rugged topography, high relief, extensive alpine tenor Tahltan and coastal Tlingit people. glaciers and snowfields, and dense rainforest at lower ele- Five obsidian flakes, presumably derived from either vations (4000 m elevation). In the south,the Scud icefield an arrowhead or cutting tool, were found at about 725 metres and glacier cover more than50 quare kilometres andjagged elevation immediately south of the Barrington River (150 peaks, suchas Ambition Mountain (frontispiece), reach ele- metres above the valley floor; Photo 1-2; Figure 1-3). An vations of more than 2900 metres. “Vanishing Lake”, a obvious source is obsidian at Mount Edziza (Fladmark, glacially dammed lake8 kilometres eastof the Scud Glacier, 1985). Trace element signatures based on x-ray refraction is subject to outburst flooding (jokulhlaups; Figure1-3: Per- analysis of the flakes confirmed their geochemical similar- chanok, 1980). In contrast to the icy and rugged Coast ity to obsidian found on Mount Edziza, specifically flow 3 Mountains in the south, the Telegraph Creek lowlands and (M. James, Simon Fraser University, personal communica- Stikine River valley upstream of Chutine River have sub- tion, 1994).The flakesprovide evidence that native peoples dued relief, with forested, glacially rounded and elongate travelled through the Barrington valley and possibly sharp- outcrops, and thick intervening Pleistoceneand Recent gla- ened an obsidian tool or arrowhead at this site, probably cial, glaciofluvial and fluvial deposits. Prominent northeast-about 4000 to 5000 years ago, in the height of the Mount vending linear features are characteristic,and local crag and Fdziza microblade industry (Fladmark, 1985). tail ridges indicate that glaciers moved towardthe southwest (Ryder, 1984). The northeastern pan of Telegraph Creek lowland is semi-arid and open grasslands are common on PREVIOUS WORK south-facing terraces. In the northeast comer of the study Initial geological studies along the Stikine River were area, Zagoddetcbino plateau averages more than 1525 me- made in 1863 when a group of Russian geologists came to tres elevation and is a remnant of a larger, late Tertiary assess the area’s mineral potential (Alaska GeographicSo- erosional surface (Souther, 1971) which includes the ciety, 1979). Dawson and McConnell were the first Cana- Tabltan Highlands and Klastine Plateau. dian geologists to explore the valley (Dawson. 1889). but

(0) (b) I I Y I

Figure 1-2. Physiographic regions of the Telegraph Creek map area (104G) after Holland (1976; a), and Ryder (1984;b).

2 Geological Sumey Branch Fkgrurc 1-3. Geographic features in the project area.

- Bzcllerin 95 3 assemblage (Pitcher, 1960); regional synthesis by Monger (1977a); mapping to the south in the Iskut River map area by the Geological Survey of Canada (Anderson, 1989; An- derson and Thorkelson, 1990); mineral deposit studiesto the southeast by Fox et al. (1976) and Holbek (1988). and geological mappingby Gabrielse (1980), Anderson (1983a) and Read (1983, 1984) to the northeast. Stikine project geological mapping was completed at 150000 scale in the Scud River and Scud Glacier map areas in 1988 (104G/5,6; Brown and Gunning, 1989a, b), Ye- hiniko Lake (west half) and Chutine River (easthalf) map areas in 1989 (104GllIW, 12E Brown and Greig, 1990; Brown er al., 1990), and Chutine River- Tahltan Lake map areas in 1991 (104G12W. 13; Brownetal., 1992a, b). Con- current British Columbia Geological Survey studies have extended 150 000 map coverage southof the Stikine project area in the Galore Creek and Forrest Kerr Creek areas (1046/3,4 and 104B/15; Logan and Koyanagi, 1989; 1994; Logan et al., 1989,1990a, b, 19921, b), and northwest around the Golden Bear mine (Bradford and Brown, 1993a. b; Oliver and Gabites, 1993). A stratigraphic studyby Gun- ning (1993b) of the Forrest Kerrarea is in progress.

EXPLORATION HISTORY Prospectors firstcame to the Stikine River valley during the early 1860s. discovering and mining placer gold (at least 64 kilograms) atBuck‘s Bar. 6 kilometres southwestof Tele- graph Creek (Holland, 1950). By the late 1800s, the search for placer gold had moved farther north to the Cassiar and Klondike, hut the Stikine River remaineda main transpor- Photo 1-1. Stone cairn on a prominent knoll north of Mount lon- tation and supply route to the northern goldfields. In the late quette (see Figure 1-3). 1200 metres above the Stikine River. 1920%the Barrington River placer depositwas discovered. It produced 45 kilograms of gold between 1906 and 1945 the first geological maps(1 :126 720 scale) and descriptions (Holland, 1950) and recent test mining yielded 12.4 kilo- of the region were producedby Forrest Kerr of the Geologi- grams of gold from ahout 36 000 cubic metres of gravel cal Surveyof Canada, who workedin the Stikine River wa- (Integrated Resources Ltd., News Release, October 21, tershed between the International border and Telegraph 1991). Creek in the years 1924 to 1929 (Kerr, 1927, 1929, 1930, During the early part of the 20th century, attention 1931, 1935, 1948a; Figure 1-1). Kerr proposedthe original turned to lode deposits (Kerr, 1948a). Exploration efforts Permian and pre-Permian division of Paleozoic strata and prior tothe 1950s were limited because accesswas restricted outlined the distribution of many of the plutonic rocks. to navigable rivers. Introduction of the helicopter resulted The Geological Survey of Canada’s Operation Stikine in discovery of significant porphyry copper deposits near in 1956 coveredmuch of the areain reconnaissance fashion Galore Creek (1955) and Schaft Creek (1957; Figure 1-1). (Geological Surveyof Canada, 1957). Ledby Jack Souther, Porphyry copper exploration continued until about 1976 it continued workin the late 1950s and 1960s and produced (Panteleyev and Dudas, 1973; Linder, 1975; Allen et al., 1:250 000 geological maps of Chutine River (NTS 104F; 1976 Fox ef a/.,1976). The early 1980s brought renewed Souther, 1959). Tulsequah River (NTS 104K; Souther, interest in the region as major companies targeted precious 1971) and Telegraph Creek (NTS104G; Souther, 1972) ar- metal deposits. The Eskay Creek, Premier, Snip, Sulphurets, eas. In Telegraph Creek map area. Souther divided the Pa- Johnny Mountain and Golden Bear projects are prime ex- leozoic strata into pre-Permian, Mississippian,and Permian amples of nearby developments or redevelopments of pre- units, and described Triassic rocks andthe Hickman batho- cious and base metal deposits in the mineral-rich region lith in detail. His work incorporated a study by Monger (Figure 1-1). There remainsgood potential to discovernew (1970) of Paleozoic rocks in parts of the Telegraph Creek porphyry copper-gold, vein, epithermal, skarn, and volcano- area. The Mount Edziza Volcanic Complex, 20 kilometres genic massive sulphide deposits. northeast of the study area, was mapped at 1:2S 000 scale between 1965 and 1976 (Souther, 1992). ACKNOn’LEDGMENTS A regional geologic framework for the Stikine River Michael McDonough was a valuable member of our area has been developed from numerous studies, including: 1988 field crew and his data and ideas are gratefully ac- biostratigraphic studies of the Devonian to Permian Stikine knowledged. David Carmichael (1988). Eric Maeckelburg

- 4 Geological Survey Branch Photo 1-2. Obsidian flakes collected abovethe Barrington River valley(see Figure 1.3). possible evidenceof ancient aboriginalhunt- ing in the area.

,(1989) and Ian Neill, David Munro and lay Timmennan John A. Bradfordcontributed significantly to Chapter '(1991) provided excellent assistanceand contributed greatly 5, and Victor Koyanagi and Flew Harvey-Kelly provided ,tothesuccessofthefield seasons. Discussionswithandfieldessential during Preparation Of thismanuscript. Dick Player is thanked for his photographic expertise and .visits by Bill McMillan, Bill McClelland and Darcy Marud thin section preparation. Fossils were identified by W.E. providedthoughtful insights. The cooperation and logistical Bamber, Lin Rui, T,p, and A.R, Sweet (GSC, ISPG, :;UPPOrt of Continental Gold CoPntion in 1988 and ofIan Calsarv). E Cordev. M.J. Orchard. H.W. Tiooer and E.T. 6 Geological Survey Branch CHAPTER 2 REGIONAL TECTONIC SETTINGAND STRATIGRAPHY

REGIONAL TECTONIC SETTING The time scale of Harland efal. (1990) isused throughout this report for isotopic ages, except for the uppermost The study area lies wholly within the Stikine Terrane Triassic, where the Norian is considered the youngest unit (Stikinia) of the northem Intermontane Beltof the Canadian (;.e.Rhaetian isnot included). Cordillera, betweenthe Coast Beltand Bowser Basin (Fig- ure 2-1). In this region, Stikinia comprises Paleozoic and STRATIGRAPHY OF THE PROJECT Mesozoic arc volcano-sedimentary successionsand coeval plutonic complexes, overlain by marine clastic rocks of the AREA Bowser Lake Group, which areoverlain in turn by less ex- The stratigraphic succession within the project area tensive continental strataof the Sustutand Sloko groups. consists of: poorly dated Carboniferous volcanic and sedmentary rocks, and well dated Permian limestone, tuff and The oldest strata are includedin the Paleozoic Stikine chert of the Stikine assemblage: Permian to(?) Middle Tri- assemblage, which is discontinuously exposed along the assic chert; Upper Triassic, dominantly submarine mafic western flank of Stikinia for over 500 kilometres (Monger, and felsic volcanic rocks and related sedimentary rocks of 1977a). The assemblage consistsof at least three well dated the Stuhini Group; Lower to Middle Jurassic subaerialand limestone units, interbedded with volcanic rocks and in- subordinate marine volcanic and sedimentary rocks of the truded by rare coeval plutonic rocks. This dominantly ma- Hazelton Group; Upper Cretaceousto Paleocene nonmarine rine succession represents remnants of the paleoPacific molasse-type coarse-grained clastic rocks of the Sustut oceanic arc system that spanned more than 150 Ma. The Group; Eocene felsic to mafic calcalkalie volcanic rocks oldest rocks of the Stikine assemblage are Devonian lime- of the Sloko Group; and Miocene to Recent (?) basalt flows stones and bimodal volcanicand plutonic rocks with primi- (Figure 2-2). A diverse suiteof granitic to ultramafic intru- tive arc signatures(Read ef a/.,1989; Anderson, 1989; Greig sive rocks ranges in age from Triassic to Eocene (Chapter and Gehrels, 1992; Logan and Drobe, 1993a. b; Logan, 3). Drobe and McClelland in preparation; Gunning, 1993b). Carboniferous limestones and mafic volcanic rocks comprise the middle sequence. The youngest sequence com- PALEOZOIC STIKKNE ASSEMBLAGE prises locally thick but laterally discontinuous Lower to Stikine assemblage rocks in the project area are Car- Upper Permian limestones, which were deposited in an boniferous and Permian in age. Devonian strata identified open-marine, subtropical environment, characterizedby lo- farther to the south (J-ogan and Drobe 1993a, b) were not cal tectonic stability. Upper Triassic and Lower to Middle recognized. The following descriptions of the assemblage Jurassic calcalkalinevolcanic successions constitute island are divided intoage divisions -Upper Carboniferous, Up- arc complexes of the Stuhini and Hazelton groups which per Carboniferous to Lower Permian,and Lower to Upper were built on these Paleozoic strataprior to amalgamation Permian: and are further subdivided into six main geo- of Stikinia with adjacent terranes; ultimate accretionto the graphical areas.These areasare: Scud River. north and south western margin of North America occurred in the Middle of Devils Elbow pluton,and in the Missusjay Creek, Chutine Jurassic (Gabrielse and Yorath, 1991). The Bowser Lake River, Banington River and Little Tahltan Lake structural Group formedan overlap assemblageon Stikinia in the Mid- culminations (Figure 2-3; Brown et al., 1992a). Descrip- dle to Late Jurassic (Evenchick, 1991a).It comprises marine tions of the two southernmost areas are based on detailed and nonmarine clastic rocks. The Sustut Group comprises studies by M.H. Gunning (1993a). fluvial sandstone, conglomerateand lesser Nff, the detrital A composite lithostratigraphic section comprises one material being derived from uplifted rocks of the Omineca formally named and four informally named divisions: the Belt to the east and Stikinia to the west. The Sloko Group Butterfly and Devils Elbow units,and the Navo formation, represents Eocene continental arc volcanism extruded east Ambition Formation (Gunning ef al., 1994) and Scud Gla- of the Coast Beltin a back-arc setting. The Neogeneto Re- cier formation (Figure24, Table 2-1). Upper Carboniferous cent stratavolcano and surrounding plateau lavas of the foliated sedimentaryand volcanic facies are called the Dev- Mount Edziza Complex were generated after a change in ils Elbow and Butterfly units respectively. Near the Scud the relative movement of the North American andPacific River, Upper Carboniferous to LowerPermian ash Nff con- plates at about 40 Ma, from almost pure convergence to formably overliesthe Butterfly unit and is named theNavo more oblique and hence a transtensional regime (Souther, formation. A thick succession of well bedded, Lowerto Up- 1992; Engerbretsonernl., 1985). per Permian limestone conformably overlies the Navo for-

Bulletin 95 7 Figure 2-1. Location of project area on a simplified terrane mapof northwestern British Columbia andits relationship 10 the regional distributionoftheStikineassemblage(modifiedfromWheelerandMcFeely,1991).Finecross-hatchedareas=Paleozoicstratacorrelated with Stikine assemblage,AX =Alexander Terrane, CC =Cache Creek Terrane,JI = Inklin assemblage (post-terrane accretion overlap assemblage), NS = Nisling terrane,ST = Stikinia (coarse cross-hatch),QN = Quesnellia. Outerbox is the outlineof the Telegraph Creek map area (104G). and the inner polygon represents the Stikine project area.

8 Geological Survey Branch ISOTOPIC DATES INTRUSIVE 1 DEFORMATIGN STRATA SUITES EVENTS T

I HvCer I I' 1 1

'i t *t i cone MOunlal" Texas Creek/ . comer VI"

A I

Figure 2-2. Schematic stratigraphic succession,showing intrusive events in the study area. Isotopic data fromHolbek (1988), White el al. (1968) andM.H. Gunning (unpublished data, 1994) are included. Intrusive suitesare discussed in Chapter 3. Regional defomational events shownin the last columnare discussed in Chapter 4. mation and is named the Ambition Formation. The Scud spany skeletalwackestone forms discontinuous intervals up (Glacierformation consists of Upper Permian tuff and chert to 30 metres thick. Silicified and folded colonial and solitary ,which conformahly overlie the limestone and includes the rugose corals (Appendix 1) occur in scattered, metre-thick youngest strata in the assemblage. concentrations. Fusulinids (Appendix 2) are rare. Echino- derm columna1 fragments are evident in thin section hutnot 'UPPER CARBONIFEROUS STRATA (UnauCS) in outcrop. The darkgrey, massive to crudelylayered lime- :DEVILS ELBOW UNIT (Unit uCSs) stone isrecrystallized to spany calciteand interbedded with rare, thin lenses of argillite. Volcanic components include The Devils Elbow unit comprises mainly sedimentary pale green sericite schist, rare aphanitic basalt flows and ,rocks with minor intercalated volcanic rocks; it grades lat- chlorite schist. Ierally to the south into the coeval volcanic-rich Butteffly onit. It is exposed north of Devils Elbow Mountain, from The stratigraphic base of the Devils Elbow unit is not which its namewas adopted, and also in theMissusjay Creek exposed. The upper contactof phylliticrocks with massive ;Kea. Correlative rocks also underlie the Chutine culmina- Stuhini Group rocks, immediately eastof the ridgenorth of lion. The total thickness of the unit is unknown because the Devils Elhow Mountain, is poorly exposed and interpreted base is not exposed andstrata are folded and faulted. to be paraconformable.An erosional contact crops outnorth The unit comprisesvariably foliated graphitic and sili- of Missusjay Creek. Limited biostratigraphy precludes ceous argillite, graphiticphyllite and pale green ash tuff in evaluating the degree of non-deposition or erosion repre- l.hin laminated intervals. Recrystallized, coarse-grained. sented by the contact (Gunning, 1993a). LEGEND Permian to Middle Triassic Wimpsonunit STlKlNE ASSEMBLAGE UpperPermian Scud Glacierformation Lowerto Upper Permian AmbitlonFormation

Carbonlferous to Permlan c] Navoformation 0Undivided Carboniferous strata 13~..~.~~ Butterfly unit 0Devils Elbow unit

Figure 2-3. Distribution of Paleozoic Stikine assemblagein the project area, thesix main areas are:(1) Scud River, (2) Devils Elbow, (3) Missussjay Creek, (4) Chutine River, (5) Barrington River and (6) nonhwest of Little Tahltan Lake.

10 Geological Survey Branch Deep-watersedimentation (locally; g: Volcanlsm/shallow-water limestonedeposition (1)

(el ...... Carbonatedeposition (dl ......

Local pyroclasticvolcanism (c) ......

A I Fringing carbonate buildups

Volcanism. (a)/sedimentation (b) Z 2 Elbow units

AGES FROM FOSSILS FUSULINACEANS/FORAMS @= normal fault F LateLeonardian (Roadian) to earlyGuadaiupian (Wordian) @E thrust fault E Early to middle Leonardian(Artinskian) x = structurally thickened D Leonardian(Artinskian to Roadian) C LateWolfcampian (Sakrnarian) to CONODONTS earllestLeonardian (Artlnskian) LatePermtan ' B Wolfcampian ) Early ,Permian A Moscovian i LateCarbonilerous-Permian 3 Carbonilerous-Permian CORALS 111 Early Permian I1 LateCarboniferous-Permian I Late Early Carbonllerous

Figure 2-4. Generalized stratigraphic column and palewnvironmental interpretations for the Stikine assemblagein the Scud River area. (a) aphantic basaltflows and tuff, (b) graphitic argillite,phyllite, limeslone; (c) felsic tuff. minor silty limestone;(d) fossiliferous limestone, minor argillite; (e) lightly folded limestone;(0 marwn fusulinid-rich limestone; (g) grey and marcon crystal-lithictuff, radiolarian chert; (h) pyroxene crystal tuff and flowdsills.

The age of theDevils Elbow unit is poorly constrained BUTTERFLY UNIT (Unit uCSv) as fossiliferous limestoneis rare and fossils ase deformed. The Butterfly unit, named for good exposures east of The unit is assigned to the Upper Carboniferous because of Butterfly Lake, extends south to the Navo Creekarea (Fig- the identification of poorly preserved nonfusulinid ure 2-3). It is characterized bymafic metavolcanic rocks foraminifers of ~~~~~~i~~ or younger age mamet, 1991) with subordinate interbedded sedimentary rocks. Total thickness of the unit is unknown because strata are folded ,and Late(?) Carboniferous conodonts (Appendix 3) col- and faulted, but may exceed ,ooo metres. lected north of Devils Elbow Mountain. The fossil ages The unit consists of faintly foliated aphanitic andrarely '3ver1ap with a U-Pb date 'Om the Buttemy pyroxene-plagioclase-phyric basalt and hornblende-phyric I:see below). A preliminary Mississippian age was repofled diabase. Foliated basalt grades into thin chlorite schist InY Ken (1948a; m2) for a small cok~tionof deformed zones. Foliated lapilli and block tuff contain elliptical basalt (corals. fragmentsscoriavolcanic and felsic and are intercalated

.Bulkfin95 I1 TABLE 2.1 U-Pb AND K-Ar ISOTOPIC DATES FOR STRATIFIED ROCKS

F IELD MAP ROCKTYPE GROUP DATING MINERAL AGEMINERAL DATING GROUP ROCKTYPE MAP FIELD NO. UNIT METHOD (Ma) DBR89-471 AndesiteTS Nff SlokoHb K-AI 48.8 i 1.7 DBR89-376 KTS Rhyolite Nff SWNt K-AI WR 51.61 1.8 DBR89-25 KTS Wacke Sustut K-Ar Bi 85.6 * 3.0

DBR90-162 Id Andesite flow bx Hazelton U-Pb Zr 185 + 7/- I Im lH Felsite Hazleton FelsiteDBR90-151 ImlH U-Pb Zr Indeterminate DBR91-717 lmm Rhyolite Hazelton U-Pb Zr 175 + 41- I CGR89-217 ImJH Andesite Nff Hazelton K-AI WR I48 + 5 CGR89-439 ImJH Andesite Hazelton K-Ar WR 166+6

MGU90-740* PyroxeneuTSv crystal Nff SNhini U-Pb Zr 227 I

MGU90-750' pPS Mela.-crystal Nff Stikine U-Pb Zr 311+6.2-10.4 MGU89-314K-AI StikinepPS schistHornblende Hb 155*5

* = From Gunning (1993a), see Appendices12 and 13 for analytical data and references.

photo 2-1. Heterolithic andesitic volcanic brecciaof the S&ne assemblage, Butterfly unit (uCSv) eastof Butterfly Lake. Clasts in. clude andesite, basalt and felsic tuff. The successionis dominated by massive basaltflows.

12 Geological Survey Branch with foliated basalt flows. Thin intervalsof light grey weath- parently undeformed siltstone illustrate the degree of inho- ering-feldspar crystal rich breccia andblock and lapilli tuff mogeneous strain. Farther southeast,poorly sortedpolymic- are distinct (Photo 2-I), though volumetrically minor. Me- tic conglomerate contains cobble to pebble-sized clasts of tre-thick beds of pale green phyllite and sericitic ash tuff limestone and siltstone, and is similar toa polymictic con- occur throughout the unit. The volcanic units are distin- glomerate east of Buttemy Lake (Figure 13 in Gunning, guished from lithologically similar rocks of the Stuhini 1993a). The limestoneclasts, up to 25 centimetres long, are Group by stratigraphicsetting (i.e. position below Permian unstrained. Foliated. recrystallized Permian limestone lies limestone where determinate), predominance of aphanitic structurally below the conglomerate and dark grey siltstone. flows, higher metamorphic grade and more intense defor- The northern contact of the Barrington River culmina- mation. Metamorphic grade andintensity ofstructural fabric tion is inferred to be a steep, east-Uending fault that places are used as a guide to distinguish Paleozoic from Mesozoic phyllite against volcanic rocks of the Stuhini Group. The strata, but cannotbe applied exclusively because Upper Tri- southern contact with the Stuhini Group was not mapped. assic strata are locally deformed and metamorphosed, as in The eastem extent of these phyllitic rocks ispoorly known. the Scud Rivervalley. In addition, pyroxenes tend to beun- zoned, small, and less calcic compared to those in the py- BARRINGTON RIVERAND LITTLE TAHLTAN roxene-rich rocks of the Stuhini Group(Gunning, 1993a). LAKE AREAS (Unit uCS) The western, lower contact isnot exposed because it is Phyllitic tuff, siltstone, andesite and limestone exposed intruded eastern, upper contact is by younger plutons. The in the Barrington River valley and northwest of Little gradational with felsic tuff ofthe Navo formation near Navo Tahltan Lake (Little Tahltan Lake culmination; Figure2-3) Creek. To the north,a Mesozoic pluton intrudes the Butter- are similar to rocks in the core of the Chutine culmination fly unit, although the contact is locally faulted. and in the Buttemy Lake and Devils Elbow area,based on A Moscovian U-Pb date of 311.1+6.2-10.4 Ma (J.K. lithology and to a lesser extent thefabric. The strata here are Mortensen in Gunning, 1993a) obtained on zircon from a more phyllitic and more complexly folded than in most other mafic crystal tuff constrains the age of these volcanic rocks areas. Their characteristic pale green, grey and maroon to Late Carboniferous. A K-Ar date of 1556 Ma was ob- weathering surfaces and homogeneous, rounded outcrops tained on hornblende from the same unit and is interpreted contrast with the more irregular, blocky Stuhini Group ex- to be thermally reset. In the Navo Creek area, the unit is no posures. younger than the Late Carboniferousto Early Permian Navo formation which overlies it. Alternating centimetre to millimetre-scale layers of green, dark grey, white and maroon rocks grade fromchlo- Nine samples from the Buttemy unit and Chutine culmination were collected for geochemicalanalysis (Appen- rite schist to unfoliated ash and lapilli tuff, siltstone and argillite. Concordant and discordant white quartz veins and dix 8). Only three samples were acceptable on the basis of screening criteria set outin Appendix 9. These samplesex- podsarerestrictedtorocksoftheBamngtonunit.Afoliated, hibit too much scatter on most majorand trace element dia- thinly layered, recrystallized grey to tan limestone, 25 me- grams to support any significant generalizations about tres thick, is complexly infolded with limy tuff and chlorite phyllite in the Little Tahltan Lake culmination. Farther Stikine assemblage chemistry. Some minor elements are north, a weakly foliated, dark green hornblende-plagio- less variable, but a detailed petrochemical characterization clase-phyric meta-andesite or flow occurs within the is not possible. Eleven mafic flows from the Butterfly Lake sill phyllitic tuff succession. In the same area, faintly foliated area aretholeiitic basalt based on the abundances of selected granodiorite dikesintrude the sequence. A foliated, recrys- elements (Gunning, 1993a). tallized limestone layer, at least 75 metres thick. crops out CHUTINE RIVER AREA in the culmination. Green and marmn chloritephyllite, ash The coreof the Chutine culmination(Figure 2-3) com- tuffs and silicic layers occurwithin and below the limestone. prises siltstone, argillite, sericitic ash tuff, and green and The pale green, grey and cream-coloured ash tuffs are thin maroon. phyllitic plagioclase-rich andesitic lapilli tuff, and bedded to laminated. Grey phyllitic siltstone and shaly silt- a granitoid-bearing volcanic conglomerate. These units are stone arealso common. Massive,coarse-grained pyroxene- correlative with the Upper Carboniferous Buttertly and phyric basalt dikes, interpreted to be Stuhini Group feeders, Devils Elbow units to the south. Fabrics vary from schistose intrude the section. Similar dikes, alsointerpreted tobeLate to unfoliated. The siltstonein the core of the Ugly antiform Triassic based on petrographic character and chemical com- (Figure 2-3;along the northwestern edgeofthe culmination) position. intrude correlative strataof the Devils Elbowunit resembles parts of the felsic tuff unit (Navo formation) that in the Missusjay Mountain and Devils Elbow Mountain ar- lies directly below Permian limestone in the Scud River eas. area. The southeastern contact of the Little Tahltan Lake cul- Brown-weathering pillow basalt, less than 50 metres mination is inferred to be a steep, northeast-trending fault thick, is intercalated with phyllitic sedimentary rocks and that places greenschist-grade, polydeformed phyllite tuff near the Ugly antiform. Individualpillows are up to 2 against lowergrade, less deformed,steeply dipping siltstone metres long, with amygdaloidal cores, well preserved and volcanic rocks of the Stuhini Group. The northern con-

13 Photo 2-2. Pillow with intrapillow micrite, a rare example of pillow basalt within the Stikinc assemblage in the study area. southeast of the Ugly anticline.

limestone are common. Pyrite euhedra, up to 1 centimetre The age of unit uCS in the Barrington River area is across, form conspicuous rusty weathering spots in some uncertain. An infolded limestone in the Barrington culmi- exposures. Intercalated thin, greyto brown dolomitic lime- nation yielded a poor collection of probable Permian cono- stone and argillite bedsand lenses predominate toward the donts (Appendix 1). However, the similarity in lithologies top of the succession. Muscovite, and lesser biotite, magne- and structural style between theBamngton area and Devils sium chlorite and calcite forma pervasive microscopic fo- Elbow and Butterfly units is the basis for inclusion in the liation. Plagioclase crystals are rare within lithic tuff. Carboniferous. Similar strata with similar structural style Decimetre to centimetre-scale, planar to curviplanar bed- are well exposedto the northwestin the Tulsequah map area ding is characteristic (Photo 2-3). Local load casts, flame (Bradford and Brown, 1993a, b) where CarboniferousU-Pb structures, fining-upward sequences, crossbeds and small- dates have been obtained (Oliver and Gabites. 1993). Li- scale growth faultsin tuffaceous siltstone consistently indi- thologically similar but undated sequences are exposed to cate a right-way-up stratigraphic succession. the southwest near Triumph Creekin the Chutine map area The basal contact is gradational with the underlying (104F Westcott, 1989a). Buttertly unit. northwest of Navo Creek. The upper contact of the Navo formation ais sharp, wavy, conformable contact UPPER CARBONIFEROUS TO LOWER with argillite of the Ambition Formation, near the toe of PERMIAN STRATA "Rugose" glacier. However, southofthe glacier andinNavo Creek,thecontactisinterpretedtobeafault,becausesteeply NAVO FORMATION (Unit uCSfj dipping, chevron-folded felsictuff beds are overlain by gen- Felsic volcanic rocksof the Navo formation gradation- tly dipping argillite and limestone. North ofNavo Glacier, ally overlie volcanic rocks of the Butterfly unit between ash tuffof theNavoformation is infolded with recrystallized "Rugose" and Oksa creeks.The formation is tightly folded, limestone of the Permian Ambition Formation. ofEast Mis- but its estimated stratigraphic thicknessis less than500 me- susjay Mountain and north of the Chutine Riverin the Ugly tres (Figure 2-4). antiform, folded siltstone directly below Permian limestone The Navo formation is a sequence of weakly foliated resembles felsic tuff of the Navo formation. Discontinuity tomassive, light grey topalegreen, fine-grained to aphanitic of the formation between Navo Creek and Devils Elbow felsic ash tuff, lapilli tuff and tuffaceous siltstone. Lenses Mountain may be related to non-deposition, post-Permian and layers of more recessive, dull brown weathering, silty erosion or a combination of both.

14 Geological Survey Branch Minisrrv ofEmployment and Investment

Photo 2-3. Fine-grained reworked felsic tuff (Navo formation; unit uCSf) with atypical, well preserved crossbeds. These depositsare interpreted to be turbidites. Most beds in the formation, however, are internally massive and resemble grainflows.

Argillite Unit (Unit IPSa) The age of the Navo formationis bracketed by the un- A basal argillite unit, well exposed between the Scud ,derlying Upper Carboniferous Buttemy Lake unit and the River and Navo Creek, forms a distinctive Nsty brown 'overlying Lower Permian limestoneunit. A few poorly pre- weathering sequence that overlies the Navo formationand :served conodonts from twothin limestone beds near the top grades upward into the limestone unit. It is about 50 metres ,of the succession are assigned a Late Carboniferous to Early thick at the toe of Rugose Glacier, at the base of the type :Permian age (Appendix 3). section for the Ambition Formation. Itis dominated by massive, black to dark grey argillite with lesser thinly bedded LOWER TO UPPER PERMIAN STRATA siltstone. Bedding-parallel bands of pyrite andor pyrrhotite areubiquitousandcompriseupto5%oftherock.Theupper AMBITION FORMATION (Unit IPS) contact of this unit is a 30-metre gradation into overlying dark grey micritic limestone. Extensive exposuresof thick, deformed Permian lime- :tone arethe most distinctive feature of the Stikine assem- Limestone Unit (Unit Iblage (Monger, 1977a). especially in the project area. The IPSc) Ambition Formation. named after the highest mountain in North of the Scud River, in the Rugose Glacier area !.he study area, is formally defined and describedin detail in (Figure 2-3), there is a homoclinal panel of Lower toUpper I;unningetal.(1994).Itcompriseslocallythickbutlaterally Permian limestone which comprises two shallowing-up- discontinous succession of limestone (Figure 2-3). Correla- ward successions. Dark grey, tine tomedium-grained skele- lion ofthe less extensiveand commonly fault-bounded suc- tal lime mudstone and minor black argillite form thelower pan of both successions (Photo24). The upper succession cessions of limestone in the Missusjay Creek and Chutine consists of more than 300 metres of centimetre to decime- River areas (Figure 2-3) is based on rock types, hedforms tre-thick beds of well bedded grey echinoderm skeletal and Permian ages.The limestone is a minimum of 500 me- wackestone and brown whole-fossil Ndstonewhich grades tres thick and is structurally thickened by folding and re- upward intolightgrey wackestoneandtan,nodularand bed- verse faults in most areas. The typesection described south ded chert (Photo 2-5). The chert is interpreted lo have of Rugose Creekis 1074 metres thick (Gunningef a1.1994). formed during limestone diagenesis.

I5 ~ ~~~

British Columbia

The limestone is particularly fossiliferous in the type section area, near Rugose Glacier. Rugose corals up to 30 centimetres long, fusulinids. fenestrate and ramose bryozoa, tabulate corals (syringopora ?), brachiopods, echinoderm stem fragments, rare sponge spicules and rare gastropods constitute a locally abundant. but low diversity fossil assemblage. Intact corals throughout the lowerpart of the succession indicate limited transport. Many fossils arein tabular, bedding-parallel concentrations interpretedto be storm deposits. The upper part of the formation is massive to thick-bedded, whiteto buff, sparry limestone that forms theof top the Permian limestone succession throughout the region. The base is locally a southwest-directed reverse fault; elsewhere the contact is poorly defineddue to rugged topography and ice cover. Subordinate argillite and maroon and green andesitic tuff are characteristicof the toppart of the limestone unit. The tuff forms concordant lensesand structurally disrupted discordant bodies up 50 to metres thick. Rare solitary corals and gastropods occurin metre-thickbeds of buff and white sparry limestone and echinoderm-skeletal packstone in the Scud Glacier outwash valley. The highest stratigraphic unit is a mauve to maroon, tuffaceous fusulinid floatstone, exposed eastof the toe of the Scud Glacier (unit UPSI). In the Chutine culmination (Figure2-3), the Ambition Formation comprises northeastto east-trending, complexly folded, well beddedto massive, light and dark grey, recrystallized limestone that forms conspicuous white cliffs north Photo 2-4. Planar, thin to medium-bedded argillaceous lime- and south ofthe Chutine River. The simplified map pattern stone and limestone (unit IPSc). resembles an east-striking anticline. In fact, lithologic units

16 Geological Survey Branch ~~ ~~~~~~~ ~

structurally above and below the limestone vary along conodonts (Appendix3). The upper age limit, Lateor Mid- strike, as does the thicknessof the limestone itself, indicat- dle Triassicis providedby rocks above these strata that are ing structural andor facies complications thatwere not re- correlated lithologicallywith the “Tsaybahe Group”of Read solved in this study. Macrofossils are much less common (1984) or lowermost Stuhini Group. than in the Scud River area,but locally the limestone contains rugose corals, brachiopods, bryozoans, and echino- REGIONAL CORRELATIONS derm columnals (Appendices 1 and 2). Perhaps the Early Carboniferous volcanic successions as exposed limestone facieshere was depositedin slightly deeperwater in the TulsequahChief (Sherlock et al., 1994). Golden Bear and hence is less fossiliferousthan in the Scud River area. (Bradford and Brown, 1993a) and Oweegee dome areas The ageof the Ambition Formation iswell constrained (Greig and Gehrels, 1992) and Early Carboniferous lime- by an abundant assemblage of Permian conodonts, stone in the Iskut River region (Logan.Robe and McClel- fusulinids and macrofossils (Appendices I, 2.3). The sec- lahd. in preparation; Gunning, 1993b). are apparently not tion examined south of Rugose Glacier provides the most present in the project area. The Buttemy lake part of the comprehensive database for Permian limestone of the Stikine assemblage succession is lithologically and age- Stikine assemblage (Gunningeral., 1994). Upper Wolfcam- equivalent to a meta-volcanic succession with discontinu- pian to lowest Leonardian (Sakmarian to Artinskian) ous, fusulinid-bearing Moscovian limestone and other fusulinids occur in argillaceous wackestone at the base of sedimentary rocks, stratigraphically above the Tulsequah the Ambition Formation and early Guadalupian Wordian) Chief volcanogenic massive sulphidedeposit (Nelson and fusulinids in the upper pat? (Appendix 2). The maroon tuf- Payne, 1984). Coeval rocks in the Golden Bear area include faceous limestone at thetop of the succession containsup- felsic phyllite that yielded U-Pbdates between 300and 320 permost Lower Permianto lowermost UpperPermian (late Ma (Oliver and Gabites, 1993). The most extensiveunit is Leonardian to early Guadalupian) fusulinaceans (Appendix the Permian Ambltion Formation limestone, extendingdis- 2) and lower Upper Permian, Guadalupian conodonts(Neo- continuously from the Tulsequah River area south to Ter- gondolella cf. phosphoriensis (Youngquist, Hawley and race. The overlying chert successionmay correlate with the Miller; Appendix 3). These are the youngest age determina-Tsaybahe Group as mapped by Read (1984) in the Grand tions for the Stikine assemblagein the study area. Canyon of the StikineRiver. The Early Permian age of the limestone delineating the Cbutine culmination is based on Asselian, Sakmarian and PALEOEWIRONMENTAL INTERPRETATION Artinskian fusulinids (Appendix 2) and Artinskian cono- The pre-Permian sedimentary strata of the Stikine as- donts (Appendix 3). The Permian age of the Missusjay semblage in the project area record pelagic sedimentation Mountain limestone is taken from Kerr (1948a; F30 and in an open-marine setting, locally in warm,shallow water F? I). within the euphotic zone. Contemporaneous, oceanic volcanism was dominated by subaqueous aphanitic basalt SCUD GLACIER FORMATION (Unit UPS) flows during the LateCarboniferous, accompaniedby dis- A section of interbedded tuff, chert and argillite rest, continuous limestone accumulation.Facies relationships in- apparently conformably (the contact isnot well exposed), dicate a subdued paleotopography, perhaps there were on maroon tuffaceons limestoneat the top of the Ambition numerous fissure eruptions in an extensional setting (Gun- Formation, near the toe of the Scud Glacier (Figures 2-3, ning, 1993a). Proximal volcanic facies related to edifice 2-5). The section is over 250 metres thick and is exposed construction havenot beenrecognized. The Navo formation only in this area. Grey,green and maroon crystal lithictuffs. represents limited felsic volcanismand submarine turbidite and tuffaceous mudstones are massiveto flaggy. Pale grey, deposition at the end of the Carboniferous volcanic cycle. felsic lithic fragments predominate over mafic fragments. Local emergent facies arenoted to the south in the Forrest Local chloritic wisps may be relict fiammt. Crystal frag- Kerr Creek area (Logan er al., 199oa). ments include plagioclase and pyroxene. The tuffs aregra- The Lower Permian in this region is represented by dationally overlain by thin-bedded green siliceous thick limestone deposition and a long hiatusin volcanism. mudstone, green radiolarian chert,thin-bedded to laminated The Ambition Formation records neritic carbonate sedimen- brick-red chert and distinctive grey and green ribbon chert. tation in a subtropical, open-marine setting, probably on a The chert is overlainby strongly contortedand disharmoni- ramp, throughout most of the Permian (Gunning, 1993a; cally folded black chertand graphitic argillite(Photo 2-6). Gunning et al., 1994). Argillite and dark grey micrite atthe The ageof the Scud Glacier formation is assumedto be base of the shallowing-upward successions indicate high early Late Permian,based on its stratigraphic position. The preservation rates of organic matter, perhaps due to high lower age bracket is the underlyingLate Permian limestone surface production and low-energy environmentsof depo- ,at the topof the Ambition Formation.Within the formation, sition. Spany, clean-washed, fusulinid NdStOne in the up- :poorly preserved conodonts from chert yield possible Per- per part of the formation accumulated in a high-energy :mian ages (Appendix 3). The exact position of the upper environment, possibly withinthe activewave-base. The ma- (contactof the formation, the top of the Stikine assemblage, roon and green tuffs, sporadicallydeposited in the Permian, lis equivocal (i.e. somewhere within pelagic strata; Figure represent isolated, episodic, pyroclasticvolcanism contem- :27 in Gunning, 1993a). but is assumed to be between the poraneous withlimestonedeposition.Themaroon and green ?unit of black ribbon chertand overlying unit of green, sili- colour suggests fluctuating oxidizing and reducing condi- oeous, radiolaria-bearing mudstone that yielded Triassic tions, either during tuff deposition in a shallow-marine to

.Bulletin 95 17 T2 Massive, coarse augite-phyrlcbasalt, locally amygdaloidal, f felsic ash tufl """ Well bedded,maroon eplclastic siltstone to poiymitlc pebbleconglomerate (ciasts. Px-phyrlcandesite. rare grani!oiCs,limestonei.graded bedding indicates uprtghl ""_ Sectton

Mass~ve.dark green pyroxene-phyric basalt flows and breccia

Raremarble blocks ""_

!000 Green to grey. laminated pyroxene'crystal tuff/wacke with massive pyroxene-phyrlcbasalt sills

Triassic? Paraconformity Permian t 500 Scud E Glacier , , ' , , , , formation 7 I~, 1

...... conodonts formation .~. ~~~ 1 ...... C-159148-159150 ,USUlinidS C-168068 1 Tl

Figure 2-5. Schematic stratigraphic columnnear the toe of the Scud Glacier. subaerial environmentor by later diagenetic processes.The structural thickness of approximately 1000 metres is ex- extent of the volcanismand how it relates to a larger oceanicposed east of Wimpson Creek. Herethe section iswell bed- arc is unknown. The change frommarmn tuff to radiolaria- ded, with parallel, centimetre-scale bedsof chert separated bearing siliceous mudstone and chert marks a change to by thin layers of chlorite and sericite phyllite. Along the open-marine, pelagic sedimentation in the Late Permian, Barrington road the exposures comprise bright green and which may have persisted until the onset of Late Triassic red, laminated to bedded siliceous ash tuff and chert lying volcanism. structurally belowwhite Permian limestone, perhaps due to reverse faulting.Kerr (1948a) states that the Permian lime- EARLY PERMIAN TO MIDDLE stone becomes interbedded with, and grades upward into TRIASSIC WIMPSON UNIT (Unit mTc) varicoloured "quartzite" (Unit mTc), although this relation- The Wimpson unit comprises buff, light to dark grey ship was not observed. This relationship is similar to that weathering chert, siliceous siltstoneand green and maroon near the toe of the Scud Glacier where Permian limestone siliceous ash tuff and radiolarian chert. It crops out in four grades up into crystaltuff and ash tuff (Scud Glacier forma- areas: near Wimpson Creek, eastof Barrington River, along tion). The more extensive Wimpsonunit maybe correlative the Barrington road, and possibly on the southern limb of with the Scud Glacier formation, however,they differenti- the Barrington River culmination(Figure 2-3). A maximum ated here because of the apparent youngerage of the former.

18 Geological Survey Branch Photo 2-6. Ribbon chert, alternating blackto grey chert and thinner argillite interbeds(unit UPS)from disharmonically folded section above less deformedturfs and varicoloured cherts.

area. These pods are either structural slivers or olistoliths. Some of these cherty rocks areinterpreted as siliceous Early Triassic conodont ages are extremely rare in the Cor- oozes which accumulated as pelagic sediments in an open- dillera (M.J. Orchard, personal communication, 1993). marine setting, below the carbonate compensation depth. Contact relationships of the Wimpson unit with under- Scattered sponge spicules occurin some beds near the Ugly lying Lower Permian limestone north of Chutine River are anticline. important, though equivocal, because they may indicate a Penno-Triassic unconfonnity. In addition, the natureof the The Wimpson unit yielded Middle Triassic and Early upper contact of the Middle Triassicchert with the Stuhini Permian microfossil ages from separate areas(localities W1 Group in this area is complicated by structural interleaving and W2 on Figure 2-3). Middle Triassic (Ladinian) radio- of the units in the Kitchener fault zone. The Wimpson unit laria and conodont species were obtained from buff chert that contains the Ladinian conodonts appears to grade and grey limestonerespectively, east of Wimpson Creek (lo- abruptly upward into tuffaceous wacke of the Stuhini Group. cality W1; Appendices 3 and 5)where they are surrounded A similar relationship is present at the toe of the Scud Gla- by Upper Triassic tuffaceouswacke. Farther east along the cier. Barrington road (locality W2), green and maroon tuffaceous chert lies structurally below Permian limestone (Ambition Formation). The chert yielded Artinskian to Kungurian ra- PERMO-TRIASSIC CONTACT diolaria, and Permian, probably Artikinsian, conodonts (Ap- RELATIONSHIPS pendix 5). Both microfossil localities are included in the Permo-Triassic unconformities are documented along Wimpson unit because green and maroon siliceous tuff oc- the length of the Cordillera in Stikinia and Quesnellia (Read cur in both areas. Alternatively, they may represent distinct and Okulitch, 1977; Read et aL, 1983). In many areasthere stratigraphic units above and within the Permian limestone is a significant break in deposition, marked locally by angu- (i.e. not structurally interleaved as currently interpreted). lar unconformities. In places there is a contrast fromfoliated An isolated, dark grey limestone pod contains Early deformed rocks to less deformed material which implies a Triassic, Smithian conodonts (Appendix 3). but is sur- tectonic event at this time (cf: Chapter 4. Tahltanian oro- rounded by Upper Triassic Stuhini Grouptuffaceous wacke geny). (unit uTSsl). Similar isolated limestone pods containing Permo-Triassic contacts arepoorly exposed in the map Early Triassic conodonts arepresent in theTatsamenie Lake area; Permian limestone commonly is faulted against, or

Bullerin 95 19 overlain unconformably by, the Upper Triassic Stuhini assic tuffaceous sedimentaryrocks is disruptedbythe Kitch- Group. However, a few Permo-Triassic contactshave been ener fault zone. The contact between LowerPermian lime- documented northeast of Devils Elbow Mountain,at the toe stone and Upper Triassic volcanic rocks along the southern of the Scud Glacier, north of the Chutine River, and along limb of the Chutine culmination was not observed. but is the northern partof the Little Tahltan Lake culmination. Theinterpreted as a reverse fault. underlying Paleozoic and overlying Mesozoicunits vary in age and character in these areas,but in general thereappears to be a youngingof the Triassic cover fromnorth to south- UPPER TRIASSIC OR OLDER MAFIC east, This suggests a periodof erosion, diachronous pelagic METAVOLCANIC ROCKS (Unit uTSmv) sedimentation and pyroclastic volcanism after Early Per- Variably metamorphosed and locally hornfelsedand al- mian limestone accumulationand prior to the onsetof Late tered mafic rocks, mapped as amphibolite and amphibolite Triassic volcanism. gneiss by Souther (1972; his unit B), underlie areas near Permian limestone is gradationally overlain by Upper Endeavour Mountain, eastof Middle Scud Creek. eastof the Permian tuffaceous limestone,tuff and pelagic sedimentary Scud Glacier, and north of the Hickman Ultramafic Com- rocks at the toe of the Scud Glacier (Scud Glacier forma- plex (Figure 2-6). The rocks near Endeavour Mountain are tion). Perhaps correlative strataof the Wimpson unit (north referred to here as the Endeavour complex; they were not of the Chutine culmination) also mark thetransition from examined in detail becausethey underlie arugged, ice-cov- Permian limestonedeposition to tuffandchert accumulation ered area. Lithologies vary from biotite schistto massive or prior to the main Upper Triassic volcanic event. Collec- brecciated pyroxenites and metavolcanic rocks. Local lay- tively, strata in these two areas indicate a transition from ering, interpreted to be relict bedding, suggests that at least carbonate rampdeposition to local and minor calcalkaline part of the unit is mafic metavolcanic material. Pyroxene- volcanism and pelagic chert deposition. More work is re- phyric basaltflows or sills are recognized in some localities. quired to determine if these changes weregradational and The north-trendingEndeavour complex,12 kilometres time-transgressive or distinctevents. long, is enigmatic, displaying attributes of both ultramafic bodies and metavolcanic rocks. According to Souther NORTHEAST OF DEVILS ELBOWMOUNTAIN (1972, p. 20) euhedral leucitephenocrysts provide evidence About 6 kilometres north of Devils Elbow Mountain for a volcanic protolith. Epidote-altered clinopyroxeneba- variably foliatedrocks of the Devils Elbowunit are uncon- salt brecciafrom this body resembles Stuhini Grouplitholc- formably overlain by massive augite-phyric Stuhini Group gies. Souther’s work identifieda fault contactwith Permian basalt. Lower Permian limestone exposed to the north at limestone in the southwestern comer of the complex. How- Missusjay Mountainand to the south at Scud River ismiss- ever, an apparent intrusivecontact between olivine clinopy- ing, implying eitheran unconformity or non-deposition, or roxene basalt and Permian limestone was observed at one both. If there is an unconformable relationship, over 1000 locality on the flank of Ambition Mountain. The Middle metres oflimestone representing mostof the Permian (about Jurassic Strata Glacier and Dokdaon plutons intrude the 80 Ma) was removed, yet the immediatelyoverlying Upper complex on the eastand west (Figure2-6). Triassic strata lack Permianlimestone clastsor a prominent basal conglomerate. All observed contacts of the complex are intrusive or faults. Theunithas compositional similaritieswith themafic TOE OF SCUD GLACIER part of the Stuhini Groupto which it is tentatively correlated, Near the toe of the Scud Glacier, fusulinid floatstone but it is barren of fossils (Appendix4). A minimum age is and rudstone at the top of the Ambition Formation grades provided by the Late Triassic and Middle Jurassic plutons up into maroon tuff assigned to the Scud Glacier formation.which intrudeit. LatePermian limestone, maroontuff and chert grade up into, and are broadly folded togetherwith, tuffaceous wackeand UPPER TRIASSIC STUHINI GROUP tuff correlated with either the “Tsaybahe”or Stuhini groups. Thinly bedded Permian ribbon chertand argillite arelocally (Unit uTS) disharmonically folded, unlike thicker bedded Triassic tof- The Stuhini Group was originally defined by Kerr faceous wacke, presumably dueto competency contrast. ( 1948b) for rocksin the Taku River valley of Tulsequahmap area. Souther (1971) included all Upper Triassic volcanic SOUTH OF SCUD GLACIER and sedimentary rocks that lie above a Middle Triassic un- South of the Scud River, Lower Permian limestone is conformity and below the Upper Triassic (Norian) Sinwa paraconformably overlainby either Daonella-bearing Mid- limestone in the Stuhini Group. Correlative strata are known dle Triassic siliceous shale or by interbedded siltstone and as the western Takla Group on the eastem side of Stikinia argillite of the Stuhini Group containing Upper Triassic, (Monger, 1977~)and the Lewes River Groupin the White- Camian conodonts (Souther, 1972; Logan and Koyanagi, horseTrough (Wheeler, 1961).In practical terms,thegroup 1989, 1994). is defined in the Telegraph Creek area as volcanic-dominated strata (predominantly Upper Triassic,but may include NORTH OF THE CHUTINE CULMINATION Middle Triassicrocks) that overlie Paleozoic or rare Lower North of the Chutine River the contact between Lower and MiddleTriassic strata and occurbelow Lower toMiddle Permian limestone and Middle Triassic chertor Upper Tri- Jurassic Hazelton volcanic rocks.

20 Geological Survey Bronck Ministgv of Emplovmenr and lnvesrmnr

Figure 2-6. Distribution of enigmatic mafic metavolcanic rocks shown in dark grey (UMC =ultramafix complex).

The Stubini Group is the dominant map unit north of tion includes highly variable bedding attitudesand recogni- the Kitchener fault zone; Stuhini Group rocks also extend tion of rare foldsin well bedded sections.Volcanic rocks of southward to the confluenceof the Chutineand Stikine riv- theStuhiniGroup,althoughsimilarinsomerespectstoover- ers, and farther south on both sides ofthe Hickman batholith lying Lower to Middle Jurassic volcanic rocks, are more (Hickman, Yehiniko and Nightout plutons; Figure 2-7). mafic and contain larger a component of subaqueousdeps- Much of the area underlain by the Stuhini Group in the its. In addition, Upper Triassic flows, sills and beds com- Eltikine River valleyis at lower elevationsand covered with monly dip steeply, whereas Lower to Middle Jurassic unconsolidated deposits and thick vegetation. The lack of successions are typically gently dipping. Augite-bearing marker units, the similarityin colour and weathering char- volcanic rocks occur in both the Upper Triassicand Lower acteristics of COnStiNent lithologies, and the lack of age de- to Middle Jurassic packages, but are more abundant and ttzrminations from the volcanic strata hinder subdivisionof augite rich in the Stuhini Group. ihe Stuhini Group, elucidationof structural geologyand re- construction of stratigraphy. Despite these limitations, an CARNIAN TO LOWER NORIAN: KlTCHENER attempt has been made to construct a composite strati- UNZT (Unit uTSsl) graphic column for the group, based on dominant lithology An east-trending belt of well bedded to massive sed- and age. mentary rocks, the Kitchener unit, which has a maximum There are two sedimentary units that interfinger with thickness of 1500 metres, extends from Mount Kitchener to various volcanic facies (Figures 2-7, 2-8). The total strati- Rugged Mountain (Figure 2-7). 'Poorly exposed. recessive graphic thickness is estimated to be at least 3500 metres, sedimentary rocks also included in this unit occur in two based on composite columns, but is poorly constrained. belts that trend east-northeast from near the confluenceof Sedimentdominated units are named here the Kitchener the Stikine and Chutine rivers. Other areas underlain pre- and Quattrin units (units uTSsl and uTSsZ), and include dominantly by sedimentary rocks,but lacking age control, tuffaceous greywacke, siltstone, discontinuous limestone include theareas near TahltanLake, northof Little Tahltan and minor shale. Volcanic-dominated facies are subdivided Lakc and north of Tahltan River (Figure2-7). into mafic and intermediate flows and tuffs. tuffaceous Sedimentary rocks are mainly brown weathering and wacke and bladed-plagioclase porphyry. Felsic volcanic composed of parallel bedded to laminated, tuffaceous silt- nxks occur only locally. Contacts between these faciesare stone, wackeand minor argillite andshale. Thinly interlay- gradational. Most of the units are believed to be submarine, ered NffaCWUS wacke, siltstone and mudstone rhythmites, based on the presenceof chert and limestone interbeds,rare probably deposited as distal turbidites, are common. The marine bivalves,and very rare pillows. Local epiclastic units Stikine and Chutine exposures include olive, mafic tuf- and rare weldedNff may have been subaerial. faceous wacke and lesser brown-weathering arkosicgrey- Stuhini Group lithologies commonly lack penetrative wacke, siltstone and shale, minor Nffaceous(?) and sandy fabrics that characterize Paleozoicunits (Photo 2-7). except limestone, limestone conglomerate and breccia, granitoid- in the Scud River valley. However, evidence for deforma- bearing polymictic conglomerate and black ribbon chert.

- BuNerin 95 21 22 Ceological Survey Branch Lower Juiasslc

Thin-bedded shale. Siltstone, wacke uTSs2 (Monof!s suDcircular;usi uoclasttc iumestone Upper Norian "__" (bivalves, corals, bryozoans)

Andesite volcan#c brecc~atull uTSv3

Intercalated sediments luTSv31 Intermediate volcanic rocks iuTSv2) uTSv2 """"""__""_""" Lower Norzan Ammonite-bearing shale, sdtstone (?I a-1 limestone and lhmy sediments Augite-bearing volcanic breccla. tuff Bladed-plagioclase porphyry

Mlddle Triassic (Ladinran) Chert, limestone Lower Triassic (Smlth~anl Limestone Artlnskian-Kungurlan Chert

Lower Permian Ltmestone

Figure 2-8. Schematic Stuhini Group stratigraphic column.C = conodont age determination,F = fusulinid age derermination.

'The polymictic conglomerate is matrix supported with cherty tuff are subordinate to the sedimentary strata. Tuf- :subangular to subrounded clasts upto one metrein length. faceous wacke and crystal lithic lapilli tuff form massive, 'The undated, massive medium-grained diorite and grano- unbedded sections of the unit and increase in abundance to (dioriteclasts resemble samples from the Late Triassicplu- the east. Coarse, heterolithic pebble conglomerate contains Tons and hence theyare the inteqxeted source of the clasts. siltstone, wacke and chert fragments and intraformational 'Volcanic clasts are also abundant, including augite basalt, limestone clasts. plagioclase-phyric andesite and minor tuff. Trough cross- Deformation within unit uTSsl appears largely fault- Idding, normal grading and fining-upward volcaniclastic controlled and high levelin a gmss sense. Forexample, the !sequences occur throughout (photo 2-8a). The huge clast sizes, scour-and-fill structures, syndepositional growth section changesfrom flat-lying strata at Mount Kitchenerto Faults and angular argillite rip-up clasts(Photo 2-8b) point vertical strata withinthe Kitchenerfaultzone. Locally, however. where the unit is dominanted by thinly bedded sedi- IOa paleodepositional surface with somerelief. Several ss- lions of pale grey weathering, thick-bedded to massive,mi- mentary strata and is less competent, it is recumbently uitic limestone (up to 20 m thick) occur within the unit, folded, suchas south of Damnation pluton. between Mount Barrington and Isolation Mountain. Mas- The age of the unit is basedon several widespreadcono- rive pyroxene-crystal lithic lapilli tuff, green ash tuff and dont and bivalve collections (from limestone layers and Photo 2-7. Photomicrographs of Stuhini Group rocks, showing well preserved primary textures and structures [upper = crossed nicols,lower = plane light]:(a) Amygdaloidalclinopyroxene basalt flow with quanz, chlorite and calcite-filled amygdules, 6 kilometres nonh of Mount Kitchener (JTI91-128). (b) Clinopy- roxene-hornblende-plagioclasecrystal tuff, 3 kilometres north of Limpoke Creek (DBR91-203), (c) Laminaledquartz-bearingtuf- faceous wacke, 6 kilometres north of Mount Kitchener (JTI91- 129).

______24 Geological Survey Branch Ministry of Employment and Investment

Photo 2-8. Unusually well exposed sedimentary structures in Upper Triassic luffaceous rocks, north of Limpoke pluton(DBR91-208): (a). Well bedded. cross-stratified epiclastic rocks that indicate a southeast paleocument for the deposit (unit uTSsl); (b) Angular silty shale rip-up clasls supported in a well sorted tuffaceous sandstone composed of rounded, aphanitic andesite lapilli.

,b//etin 95 25 - TJgd I

i ! I I

Photo 2-9. View northwest to Camian limestone cliffs(subunit L1) southwest ofTahltan Lake; the section is unusually thick for Stuhini Group carbonate in the study area (DBR91-124).

shaly beds, respectively) with taxaassignedcamian to early Norian ages (Appendices 1, 3; Figure 2-8). LIMESTONE HORIZONS (Subunit L1) Discontinuous fine-grained limestone units occur within both the Kitchener sedimentary and volcanic facies. They form prominent light grey outcrops in four areas: Mount Barrington - Isolation Mountain, west of Tahltan Lake (Photo 2-9). the Castor pluton area, and north of the Tahltan River (Figure2-7). Contacts are rarely exposed but they appearto be conformable. Most limestones are less than 30 metres thick and, unlike the Permian or older carbonates, are not significantly recrystallized or foliated. West and south ofTahltan Lake, the unitis morethan 100 metres thick and dips gently, whereas in most other areasbeds arethinner and steeply dipping. Alongthe southern contactof theCas- torpluton, thelimestone is 25 metres thick, well bedded and has a porcellaneous texture. A small limestone pod northwest of Little Tahltan Lake hasphyllitic, deformed margins adjacent to chlorite phyllite and massive Stuhini andesite. Photo 2-10. Heterolithic brecciawilh angular volcanic fragments A heterolithic breccia, containing angular limestone blocks andsubroundedplutonicclasusouthofGlomerateCreek;plutonic clasts may have had a more distal source relative to the volcanic up to 8 metres across, and smaller plagioclase-porphyritic debris (unit uTSv; DBR8947). The breccia was interpreted to be andesite and rare granitoid clasts supported in a coarse limy Jurassic hy Kerr(1948a). however,a correlalion to Upper Triassic volcanic matrix is exposed at the top of a limestone unit Stuhini Group is suggested by our new Upper Triassic fossils north ofGlomerate Creek(Photo 2-10). A feldspathic wacke (Appendix I, DBR89-48). and polymictic conglomerate contains subrounded clastsof

26 Geological Survey Branch ~~ ~~ ~ massive hornblende granodioriteup to 30 centimetres in di- petrochemical link to spatially associated Alaskan-type ul- ameter. We believe the undated clasts arederived from coe- tramafic intrusive bodies. This is discussed in Chapter 3. val Late Triassic plutons. This deposit is interpreted to be A fault-bounded panel of mafic tuff and argillite cor- adjacent to a paleofault scarp and the blocksrepresent sub- related with strata north of Missusjay Creek and with other marine talus material. mafic Stuhini volcanic rocks yielded a 227+1 Ma U-Pb zir- Most limestone bodies contain Carnian conodonts; con date (Camian;J.K. Mortensen in Gunning, 1993a). The however, the limestone 7 kilomews southwest of Tahltan date suggests the strata are coeval with the Kitchener unit. Lake has late Ladinian to Camianconodonts (Appendix 3). Early Norian ammonites and late Camian to early Norian INTERMEDlATE VOLCANICROCKS (Unit uTSv2) conodonts provide a precise age in the Stikine and Chutine Massive, plagioclase-rich, andesitic block-tuffs, tuffs rivers area (AppendicesI and 3). In addition, two localities and flows predominate in the area south of Shakes Lakes with fossils interpreted as Lower Jurassic by Ken (1948a) and on the ridges immediately south of Strata Creek(Figures near Glomerate and Flag creeks, yielded probable Norian 2-7, 2-8). Green and maroon, plagioclase-porphyritic an- macrofossils (Appendix 1). These ages suggest that the desite fragmentsare characteristic components.An andesi- Lower Jurassicunits previously mapped in the Stikineval- tic composition is inferred for the flows, from the ley by Kerr, and Souther(1 972). are probably Upper Triassic coexistence of plagioclase and hornblende; locally, em- andpartoftheKitchenerunit.Itisnotpossib1etodistinguish bayed volcanic quartz crystals occurwithin lapilli tuff. The the Camian and Norian limestones onthe basis of lithology. unit is lithologically similar to part of the Lower Jurassic Unuk River Formation (Hazelton Group), south of the Iskut VOLCANIC FACIES (Unit uTSV) River, however, diagnostic pyroxene-rich flows of the In general, the Kitchener sedimentary unit between Stuhini Group overlie it, so it is included in the Stuhini Mount Kitchener and Barrington River interfingers with, Group. Mappable subunits include maroon volcanic rocks and is overlain by, mafic and intermediate volcanic rocks. (uTSv2m; c) and distinctive beds of white to lightgrey, well The basaltic flows, breccia and tuff are also well exposed bedded, hornblende-rich epiclastic rocksexposed on a ridge elsewhere, including northeast of Rugged Mountain, Mis- northwest of the Brewery pluton (uTSv2m). The distribu- susjay Creek, northeast of Devils ElbowMountain and west tion of the distinctive hornblende-rich tuffaceous wacke ofthe Scud Glacier. Detailed descriptionsofbasalt nearMis- suggests a subhorizontal attitude for the massive strata of susjay Creek andin the Scud River and Scud Glacierareas this area. The maroon rocks that overlie dark grey siltstone are found in Gunning (1993a). Thebladed-plagioclase por- and shale arebrick-red, poorly sorted, heterolithic volcanic phyry facies typically underlies areasto the north and north- conglomerates, which contain abundant limestone clasts west. It is dominated by mafic and intermediate volcanic and boulders, some measuring up to 10 metres in diameter rocks, although volumetrically insignificant felsic units are (Photo 2-11). The limestone olistoliths indicate a high-en- widespread. The following discussion of volcanic facies ergy environment, and contact relations with marine silt- ~(uTSvl to4) is based on compositional affinity. Strati- stone andshale indicate transport from a high to low-energy ,graphic position of the facies variesand similar lithologies setting. The maroon rocks are interpreted to be debris flows ;are probably repeated in successive volcanic cycles (Figure (lahars) which incorporated reefoidal limestone blocks as :2-8). they flowed down the flank of an Upper Triassic volcanic edifice. IMAFIC VOLCANIC ROCKS(Unit uTSvl) TUFFACEOUS WACKE(Unit uTSv3) The most distinctive Stuhini Group lithologies are mafic volcanic rwks, including clinopyroxene-hornblende Olive-green medium-grained plagioclase-rich tuf- and plagioclase-phyric, locally amygdaloidal basalt or ba- faceous wacke forms massive outcrops north and southwest saltic andesite flows andcrystal-lithic lapilli tuffs. They are of Shakes Lake (Figures 2-7, 2-8). Like unit uTSv2, it is typically dark green, massive, and contain distinctive. rarely bedded, but lacks large fragments. It grades intoin- blocky clinopyroxene and lath-shaped plagioclase phe- termediate volcanic rocks of unit uTSv2 and may represent nocrysts. Composition of the tuffsis similar to flows. Lapilli a more distal facies. lo block size (2 to 75 fragmentscm) are supported in a crys- BLADED-PLAGIOCLASE PORPHYRY (Unit uTSv4) tal-rich matrix. Monolithic amygdaloidal basalt breccia, interpreted as autobrecciated flow. occurs locally. A Brown-weathering bladed-plagioclase phyric basalt or pyroxenite clast in a reworked(?) lapilli tuff southwest of basaltic andesite flows predominate northeast of Tahltan Shakes Lake suggests that an ultramafic intrusion, perhaps Lake and form isolated exposures north of Tahltan River the Latimer Lakebody, was unroofed during the deposition (Figure 2-7). Series of flows are at least 150 metres thick. of the tuff. Minor epidote-carbonate veinlets are commonin although individual thicknesses are unknown. A bladed por- the basalt. Layering in tuff unitsis uncommon and attitudes phyry unit, 25 metres thick, interpreted to be a sill, is ex- are generally obtained on interbedded finer grained pyro- posed on a cliff face I kilometre southof Tahltan Lake. clastic or volcaniclastic units. Pillowed basalt flows were VOLCANIC SUBUNITS recognized only locally, for example, northeast of the confluence of the Stikine and Chutine rivers. Fekic Volcanic Facies (Subunit uTSvfl Basaltic flows and tuffs of unit uTSvl are clinopy- Pale green to darkgrey, pyritic, laminated siliceousash mxene rich and lack orthopyroxene, suggesting a possible tuffs are most common, but siliceous lithiclapilli tuff and

Bu//efin95 27 Photo 2-1 1. Large, angular limestone boulder, 3.5 metres in di- Photo 2-12. Light grey weathering dacitic lapilli tuff (recessive) ameter,in maroon volcanic conglomerate (unit Ibx), a coarse and ash luff (resistant) beds (unit uTSvf). north of ConoverCreek. facies ofunit uTSv2, southwestof Brewery pluton. This boulder, Lithic fragmentsof similar lithology occur in mafic augite crystal too large to be mansported by fluvial processes, must have been tuff elsewhere in the succession. carried by a debris flow that incorporated limestone. Such deposits indicate a high-energy, unstableand cannibalistic setting, possibly spatial association with the Hickman batholith. The plutonic eroding the limestone fromthe flank of a slratovolcano. clasts are hornblende granodioriteto quartz monzonite and are interpreted to be derivedfrom theLate Triassicplutons. welded to unwelded ignimbrite occur locally (Photo2-12). Another possiblesource is the Devonian ForrestKen pluton Pale greento grey, fine-grained to aphanitic silicic and felsic (Logan et al., 1993a). however. its granite and diorite com- tuffs north of Schaft Creek are interpreted to be waterlain positions are dissimilarto the clastsin the conglomerate. ash tuffs. In places, maficcrystal-lithic tuff and tuff-breccia The conglomerates indicate that significant unroofing contain rare felsic clasts. Compositions of the flows and of plutonic rocks occurred during Stuhini volcanism. A fragments in pyroclastic and volcaniclastic rocks span the modern analogue may be the2 Ma Takidani granodiorite in mafic to felsic spectrum, but aredominantly mafic to inter- the Japan Alps, which has already been unroofed mediate. (Harayama, 1992).

Polymicfic Conglomerate (Subunii hcgl) UPPER NORIAN: QUATTRIN UNIT A mappable subunit of polymictic conglomerate (does (Unit uTSs.2) not include the isolated exposures previously mentioned) The Quattrinunit includes theyoungest rocks assigned with abundant granitoid clasts is exposedin three areas: the to Stuhini Group and occurs in a disrupted clastic andpyro- headwaters of Strata Creek. along the western margin of the clastic succession exposed between Strata and Quatuin glacier at the headwaters of Quattrin Creek. and on both creeks (Figures 2-7, 2-9). Several subunits of pale grey sides of the Scud Glacier (Figure 2-7). The conglomerates weathering, thick-bedded tomassive, micriticand bioclastic vary from matrix to framework supported and contain limestone up to20 metres thick occur at thetransition with prominent clasts of lightgrey granitic rocks, together with stratigraphically lower, massive flows and breccias to the variably epidotized volcanicrocks, dark green augite basalt, southwest (unit uTSv). Dark grey to black siltstone, green and rarely, amphibolite. limestone and ultramafite (Photo and pale grey arkose and black shale overlie thelimestone. 2-13). Cobble to pebble sized clasts are rounded to sub- Maroon, mauve and brick-red massive lapilli tuff, tuf- rounded. The conglomerates are distinguished from the gra- faceous mudstone and lesser laminatedlimy ash tuffoverlie nitoid-bearing conglomerates inunits uTSsl andL1by their the sedimentary rocks. A similar unit forms a narrow east- position within volcanic-dominated successions, by the trending belt which crosses Helveker Creek (Photo 2-14). greater portion of plutonic clasts (IO to 35%) and by their There, large lenses of steeply south dipping, thick-bedded

28 Geological Survey Brmch Ministry of Employmenr and Invesrmenl

Photo 2-13. Shlhini Group heterolithic breccidconglomeratecomposed of volcanic and plutonic fragments(unit hcgl), along theeast and west sides of Scud Glacier (DBR88-299). Volcanic blocksare coarse augite-phyric basalt and finer grained andesite. Plutonic clasts, up a metre in diameter, are hornblende monzonite, believedto be derived from the nearby Hickman pluton.

EG I Fine-grainedbioclastic IimeStone blocksalong unconf0rm:ty. Coral, brachiopod fragments

Well bedded IufiaCeOUS shale,Siltstone. wacke and IImy SillSlone, 350 Browntoblack weatnermg. recesswe. laminatedtothln-bedded, """""_ planarand gradea beddtng, rare limestone Clasts 4oo Well bedded maroon tuff.mudstone, crystal-lithic lapiiil tuff: ,.. , .. intercalatedmaroon laptlli tuff and green andesite """""_ Plagioclase-rlch tuff, wacke.black shale, SIllCeOUS si1tstone. 300 Thln to medlumbedded. wllh rare K-spar crystalfragments Synsedimentaryfolds, load casts.normal graded Deddtng -. -____-__. ------Sil~ceausSiltstone. shale (130 Massivegrey limestone, scatteredechinoderm columnals ------.

Masslve.plagtoclase-vch voiCan8c breccla. abundantgramtoid cobbles. lesser lhmestoneClasts

Green,massive andeslte crystal-lithlc tuff, :lows

Crowdedplagioclase-phyric green andmauve andeslte YOlCan~C breccla.iapilll lull

T3 Base not exposed

Figure 2-9. Schematic Stuhini Group stratigraphic columnfrom the headwafers of Strata Creek.

Bullelin 95 29 British Columbia

Photo 2-14. Unconformable contactof Stuhini Group sedimentary rocks(unit uTSsZ) with overlying Jurassic volcanic rocks (unit ImlHv), HelvekerCreek valley. The erosional surface has high relief but no basal conglomerateis evident in this area. to massive limestone and minor thin-bedded, light grey kaline field. Pyroxene-porphyritic flows and breccia from chert, grade upward into well bedded, dark grey siltstone the lower part of Stuhini Group in the southern part of the and green sandstone. A few coalified plant fragments were project area are mainly basaltwith less abundant absarokite found at onelocality. (Gunning, 1993a). They have similar characteristics to the Fossil control for the sedimentary unit is provided by samples discussed above, falling along the alkaline-subal- occurrences of thelate Norian macrofossil, Monoris subcir- kaline field boundaries. All of the samples are medium to culnris, reported by Souther (1972; Figure 2-9; Appendix high-potassium hasalts(Figure2-IOd), with halfofthesam- I). Late Norian conodonts were also collectedfrom a lime- ples in the high-potassium basalt category. Eight samples stone unitdirectly below the clasticrocks (Figure 2-9; Ap- have shoshonitic affinities, with KzO greater than 1.8%, pendix 3). KzOMa20 greater than 0.6, Ti02 less than 1.3%. near silica saturation, and low iron enrichment (Momson, 1980; de CHEMISTRY AND TECTONICSETTING OF Rosen Spence, 1985; Gill and Whelan, 1989). One sample, THE STUHINI excluded in accordance with one of the alteration criteria GROUP (KzOMazO >2.0%), may be partof the shoshoniticassocia- Major and trace element geochemical data for 32 sam- tion. ples from the Stuhini Group are tabulated in Appendix 8. Data from 18 samples of flows or sills were plotted after Trace element plots support characterization of the applying criteria to filterout altered samples (Appendix 9). Stuhini Group asan arc-related volcanic succession,an in- Two additional samplesof probable StuhiniGroup were interpretation compatible with regional tectonic relationships cluded in this data set (MGU89-215, MGU89-239). Most (e.& Souther, 1977). the dominantly calcalkaline composi- samples in the relatively unaltered subsethave undergone tion of the volcanic rocks, and the abundance of porphyritic some alteration and contain small veinlets and patches of flows and pyroclastic rocks. The suite clustersin the island chlorite, carbonate andother secondary minerals. Effects of arc field on Shervais’ (1982) Ti-V plot (Figure 2-lla). alteration were minimized by avoiding obvious veining, Mullen’s (1983) Ti02-MnO-Pz05 plot shows the Stuhini brecciation and alteration duringsampling, but some alkali Group as dominantly calcalkalinebasalt (Figure 2-10e). An mobility can be expected in weakly chloritic orcarbonate- arc interpretation is also supported by Pearce and Cann’s altered samples. Petrological characterizations based on (1973)Ti-Zr-Srplot(Figure2-1lb),wherethesamplesclus- major element plots are supported by petrogenetic plots ter near the calcalkalineisland-arc basalt boundary. The lin- which use relatively immobile trace elements. A11 samples ear cluster points toward the strontium apex, suggesting are pyroxeneorplagioclaseand pyroxene-phyric. Metamor- either strontium metasomatism during regional metamorphic grade ranges from zeolite to lower greenschist facies. phism or plagioclasefractionation. The Stuhini Group includes tholeiitic to calcalkaline Ten samples plotted on mid-ocean ridge basaltnormal- (Figure 2-loa) basalts, basaltic andesites, trachyhasalts and ized spidergrams (Figure 2-1 IC) display a signature typical basaltic trachyandesites (Figure2-lob). The suitestraddles of subduction-generated calcalkaline and shoshonitic vol- the subalkaline-alkaline boundary on the alkali-silica plot canic arc basalts, with strong enrichments in lithophile ele- (Figure 2-IOc), with five of the samples plotting in the al- ments (Sr, K, Rb and Ba) and flat Nb, Zr, Ti and Y trends

30 Geological Survey Branch 4.5 1 high-K {

41 3.5 . -M +2 3- L

.5I/ i QL 45 Si02 (wt %)

Mn0'10 p2°5*

Fizure 2-10, Major element geochemical plots for Stuhini Group basalts. Triangles denote Stuhini Group; squares denote possible Stuhini Group (cf. Appendix2-1). (a) AFM plot (after Imine and Baragar,1971);(b)plotoftotalalkaliversussilica(afterLeMailrr, 1989). Pc=picrobasalt; F=foidire; Ul=tephritelbasanite; UZ=phonotephrite; U3=tephriphonolite; Ph=phonolite; B=basalt; Sl=rrachybasalt; SZ=basaltic uachyandesite; S3=trachyandesite; T=trachyte/trachydacire; Ol=basaltic andesite;02=andesite: 034acite; R=rhyolite; (c) plot of total alkali wersus silica showing overlap in the alkaline and subalkaline fields (after Imine and Baragar,197l);(d)plofofK~Overs~SiOZ(afterLeMaitre,1989); (e) ternary plot of 'EO?- MnOxlO - PzOsxlO. OIT=ocean-island tholeiites; MORB=mid-ocean ridge basalts; IAT=island arc tholei- 0~~'""'''~ 35 4Q 45 5Q 55 60 65 70 '15 80 85 ite; OlA=ocean-island alkaline basalt; CABsalcalkaline basalt Si02 (wt %) (after Mullen, 1983).

E:ullefin95 31 Ti/1000 (ppm)

A Hilhin-plate basalt% E Island-arc basalto C: Mid-ocean-ridge basal- 10 /"T7

I I Zr sr/z 10 100 1000 zr hem)

Figure 2-11. Trace element discrimination diagrams for Stuhini Group basalts. Triangles denote Stuhini Group; squares denote possible Stuhini Group (cf. Appendix 2-1). (a) Plot of V versus TdIOOO (after Shervais, 1982). OFBxxean-flwr basalt; @) fer- nary plot of Ti100 - Zr - Sr/2.OFB=ocean-flwr basalts;IAB=island arc basalts:CABaalcalkaline basalts (after Pearce andCam. 1973);(c) multi-element spidergram for'samples: CGR89-10; CGR89-183.CGR89-264. CGR89-268 CGR89-335.CGR89- 554, DBR89-281, MGU88-176, MGU89-254, MGU89-267 and MGU89-270-1. The pattern is typical of island arc basalts. Nor- malized against mid-ocean ridge basalts using values from Pearce (1982): Sr=120 ppm; Kz0=0.15%; Rb=2ppm; Ba=20 ppm; .OI"""""'J Nb=3.5 ppm; Pz0~=0.12%;Zr=90ppm;TiOz= 1.5% Y=30ppm; Sr K Rb Ea Nb P Zr Ti Y Cr Cd50ppm; (d) Ternary plot ofTV100-Zr- Yx3. A, B=low-potassium tholeiites; Bacean-floor basalts; B, Cralcalkaline basalts;D=within-platebasalts(afterPearceandCann, 1973);(e)plot of log (ZrN)versus log Zr (after Pearce andNom. 1979). Pearce (1983) uses this diagramto distinguish arc volcanics eruptedon oceanic cmst from those erupted on continental crust, withconti- nenlal arcs aboveZIN = 3.

32 Geological Survey Branch (Pearce, 1983).The slight enrichmentin niobium and higher to accumulate in the west (relative to present orientation of average concentrationof niobium relativeto zirconium sug- Stikinia), whereas in the east, interfingering basaltand an- gest a weak within-plate signature typicalof alkalic ocean- desite flows were an important component.As the volcanic i:rland basalts. Zirconiudyttrium ratios are also indicators pile thickened, there was local carbonate accumulation,possibly as fringing reefs. Eventually the proximal eastern fa- oC within-plate enrichments. A few samplesplot in or near cies of flows, volcanic breccia and tuff prograded westward the within-plate field on the li-Zr-Yplot (Figure 2-lld), over the distal facies. The western migration of volcanism while on a Zr versus ZrN plot (Figure 2-1 le), several sam- may have coincided with emergencesome of of the volcanic ples plot outside the oceanic-arc field toward higher Zr/Y edifices. Rare. welded dacite tuff and maroon fluvial epi- values. Similar weak, within-plate signatures are sometimesclastic rocks containing polymictic subrounded granitic and seen in arcs along continental margins, where subcontinen- carbonate clasts indicate local subaerial conditions. The til lithosphere undergoes melting (Pearce, 1983). coarse conglomeratelbreccia unit required a high-energy system, probably reflecting significant relief, to transport LIEPOSITIONAL ENVIRONMENTS the clasts. Clast compositions indicate that unroofing of The following is a synopsis of Triassic stratigraphic Hickman suite plutons was synchronouswith deposition of evolution in the project area.The rock record forthe Lower the upper partof the Upper Triassic volcanicpile. Carnian Triassic is poor, as it is elsewhere in the Cordillera. The limestone deposition northof the Tahltan River occurred at Ekly Triassic black micritic limestone pod surrounded by a transition from volcanic to sediment-dominated settings. Cknian tuffaceous wacke of the Stuhini Group suggests thatDistal turbidites of the late Norian Quattrin unit represent the pod may be an olistostrome.The paucity of coeval Early the final record of Triassic,lowenergy submarine deposi- Triassic strata maybe due to limited primary deposition,to tion in the map area. erosion or to lack of data. By the Middle Triassic,deep-water chertwas deposited LOWER TO MIDDLE JURASSIC unconformably on Lower Permian limestone and older HAZELTON GROUP (Unit ImJH) strata in the Wimpson Creek area (Figure2-8). its areal dis- bibution was limited, possiblyhy arc topography. An influx Lower to Middle Jurassic volcanic and minor sedimen- o'f fine tuffaceous material, probably from distal volcanic tary rocks underlie a 100 square kilometre outlier centred centres, gradually overwhelmed chert depositionin Carnian around Helveker Creek, and also outcrop northeast of Ye- ti.me (Kitchener unit). Interpretations based on facies trendshiniko Lake, where they were mappedas Stubini Group by are hindered here because the polarity of the arc remains Souther (1972; Figure2-12). They represent the northwest- unknown. However, thick tuffaceous sediments continued em-most extent of the Hazelton Group yet recognized. A

Susiut Group /Hazelton Group Sluhini Group 13 * U-Pb Sample locality [aPlutonic rocks Amygdaloidal basalt volcanic rocks A K-AI sample locality 0 Fossil locality Saffron pluton Rhyollte ilow Sedlrneniaiy rocks

Figure 2-12. Distribution of Lower io Middle Jurassic HazeltonGroup. Potassium-argon dates: I = 162?7 Ma, Il = 162t7 Ma, III = 1666Ma, IV = 1486 Ma. Uranium-lead dates: A = 185%-1 Ma, B = 175+4-1 Ma, C =indeterminate.

- Bulletin 95 33 composite stratigraphic column (Figure 2-13) is based on pink rhyolite (unit ImlHr). and an uppermost basalt flow three well exposed areas: Crocus Mountain, the ridge be- breccia with local pillow fragments and discontinuous lime- tween Strata and Quattrin creeksand aprominent cirque in stone lenses (unit ImJHb). the headwaters of Kirk Creek, where a paleomagnetic study was conducted (Vandal1 et al., 1992). DACITE UNIT (Unit UHd) The composite Jurassic section is over 1000 metres thick and is characterized by gently dipping, massive pla- Buff to rusty weathering aphanitic dacite (upto 300 m gioclase-rich andesiteflowsand tuffs with maroonorpurple thick) is exposed at the base of the section and has been hues (unitImTHv; Photo 2-15) and is typified by exposures traced southward from Crocus Mountain for abut 3 kilo- between Kirk Creek and the ridge south of Crocus Moun- metres (Photo 2-16; Figure 2-13). Its keel shape with a flat tain. The section is subdivided intofive units: a local basal top somewhat resembles a laccolith, however, its tongue- dacite flowor sill (unit IJHd; Figures2-12, 2-14), a discon- like distribution over Stuhini volcanic and sedimentary tinuous limestone and fossiliferous limy arkosic wacke (unitrocks is more akinto afelsic flow. These featuresare enig- IJHs), extensive andesite flows and breccia (unit ImJHv), matic and it remains uncertain whether theunit is aflow or a sill.

Lithologies (map units1

sara~tflows ana pillow batall breccia (Unit ImJHbl

9._ .A ......

....

Andesitic breccia. flows r. inlercalaled luffs (Unit IrnJHv)

Limy wrlcke (Unit IJH4

Basal dacitic llow I?) (Unit IJHd)

Figure 2-13. Schematic stratigraphic columnof the Hazleton Group near Crocus Mountainwith approximate location of U-pb, K-A~and fossil dates indicated. Dating method depicted by: open circle = K-Ar, and solid triangle = U-Pb. Fossil dates; A = ammonoids, B = bivalves, C =conodonts.

34 Geological Survey Branch Ministry of Employment and Investment

Photo 2-15, View northwest to prominent angular unconformity separating folded (steeply dipping, northeast-verging overturnedbeds) . and faulted Upper Triassic (Norian) Stuhini Group siltstone and sandstone(unit uTSs2) from gently dipping Lower to Middle luyssic Hazelton Group volcaniclastic mcks and flows(unit ImlHv); ridge between Strata and Quatvin creeks.U-Pb sample location shownby ‘‘X” on photograph, the 185 +7-1 Ma date constrains deformationas prc-Toarcian. Note the relativelyflat contact (subdued relien relative to the high relief shown in Photo 2-14. 12 kilometres north-northwest.

The massive and locally flow banded, fragmental dacite The wacke contains ammonite and Weyla fragments, contains scattered very fine grained plagioclase phenocrysts belemnites, abundant terebratulid brachipods and scarcebi- altered to calcite. The uppermost part of the dacite unit, ex- valves. The ammonite fragment suggests a Toarcian age posed directly south of Crocus Mountain, is a green-weath- (Tipper, 1989; locality F1 on Figure 2-12; Appendix 1). ering, plagioclase-rich, crystal lithic tuff that is locally welded. This tuff yielded too few zircons to obtain a mean- ANDESITE FLOWSAND TUFF(Unit ImJHv) ingful U-Pb date (J.K. Mortensen, written communication, Most of the section between Strata and Quattrin creeks 1992). The tuffcontainslimestone fragmentsthat have simi- consists of a series of andesite tuffs, breccias and flows. The lar textures to an overlying limestone unit 10 metres thick. thick flows (up to tens of metres) occur in subequal quanti- ‘Thecreamy grey weathering limestoneis massive to thickly ties with tuffs. Crystal-lithic andesite tuff-breccia (Photo 2- bedded with bivalve fragments throughout. Tuffaceous 17) and lapilli tuff are commonly maroon to brick red and wacke (unit IJHs) above the limestone interfingers with less typically grey-green to mottled maroon and green. They lesser, brown-weathering amygdaloidal andesite flows. containangularvolcaniccountryrockfragmenLsupto1me- tre in diameter. Thin to thick-bedded units of poorly indu- .LIMY WACKE (Unit IJHs) rated. flaggy, maroon, mauve and pale green ash and The recessive, poorly exposed buff-weathering limy tine-grained lapilli tuff are commonly interbedded with ,wacke forms a discontinuous horizon immediately south of coarse-grained tuffaceous rocks. Pale grey grit and maroon CrocusMountain. Therecessivenatureofthesesedimentary tuffaceous grit, probably derived from underlying plutonic ~:ocksmay mean they are more extensive than currently rocks. crop out northeast of Yehiniko Lake and on Mount mapped. The unitcomprises limy wacke,turbiditic ash tuff Kirk. The most common flows are pyroxene and plagio- ;and minor lithic lapilli tuff. Rare, black silty shale lenses clase-phyric andesite. They are typically grey-green with a were processed unsuccessfully forradiolaria (Appendix 4). faint dark purple or maroon hue and are locally flow banded Dark purple to maroon pyroxene and plagioclase-phyric an- and amygdaloidal (zeolite, calcite, chlorite, epidote, quartz, desite flowsof unit ImlHv overlie the wacke horizon. pyrite). The intervening plagioclase crystal lithic lapilli tuff The volcanic rocks above the limestone appear to be is locally weakly welded. submarine based on their predominant green colour, lapilli The Kirk Creek section comprises about 150 metres of tuff with glauconite-rich matrix and intercalated limy beds flows and tuffs (not studied) overlain by IC0 metres of hearing marine bivalve fragments. aphyric, amygdaloidal basalt flows and mauve to red vol-

13ulletin 95 35 .

15 """"""""""' 35 35 35 35 35 Si02 (wt %) FeO'

.ol'"~"'"'" Sr K Rb Bo Nb P Zr Ti Y Cr

Figure 2-14,Major and trace element geochemical plots for Hazel- ton Group volcanicrocks: (a) Plotof total alkaliversus silica (after Le Maiue, 1989). Pc=picrobasalt; F=foidite; Ul=tephrite/basan- ite; U2=phonotephrite; U3=tephriphonolite; Ph=phonolite; B=basalt;Sl=trachybasalt; S2=basaltic tracbyandesite; S3=trachyandesite; T=trachyte/trachydacite; Ol=basaltic andesite; 02=andesite; 03=dacite; R=rhyolite; (b)AFM plot (after Irvine andBaragar, 1971 ); (c) plotof totalalkali versus silica (after Irvine and Baragar, 1971); (d) plot of log(Zrly) versus log Zr for five mafic samples (after Pearce and Norry, 1979). Pearce (1983) uses this diagram to distinguish arc volcanics eruptedon oceanic CNSI from those eNptedon continental CNSt, with continental arcs above ZriY = 3; (e) multi-elementspidergram for samples: CGR89-30, CGR89-217, CGR89467, CGR89-511 and DBR89- 430. Thepattern is typical of island arc basalts. Normalized against mid-ocean ridge basalts usingvalues from Pearce (1982):Sr=120 pprn; Kz0=0.15%; Rb=2 ppm; Ba=20ppm; Nb=3.5 ppm; PzO5=0.12% Z~90ppm; TiOz=1.5% Y=30 ppm, C-250 ppm.

36 Geological Survey Branch Photo 2-16, View northeast to Stuhini Group rocks (unit uTSV)overlain unconformably by pale-weathering rhyolite flow (unit IJHd) which isin turn conformably overlain bya relatively thin layer ofgently dippingToarcian sedimentary rocks(unit UHs) and by prominent cliffs of calumnar jointed Lower to Middle lurassicbasaltic andesiteflows (unit ImlHv) northeastof Strata Creek. caniclastic rocks (Divisions D-1 and D-2 on Photo 2-18, less flow-folds. The rhyolite is aphanitic, to locally auto- Figure 2-1 3). The flows, up to 5 metres thick, are dark brown brecciated, with rare spherical vesicles lined with silica. to faintly maroon. with characteristic abundant and large Flow banding and local welding, and the tongue-like ge- amygdules (filled with calcite, chlorite andzeolites). Flow ometry suggest that it may represent an ignimbrite deposit. margins are commonlybrick red, finergrained (chilled) and Rhyolite is overlain by coarse, heterolithic volcanic breccia. locally brecciated (flow-topbreccia). They are intercalated presumably debris-flow deposits. with and overlain by mauve epiclastictuffs. The flows and tuffs thicken to the northeast. The well bedded, medium to BASALT (Unit ImJHb) ,coarse-grained epiclastic rocks display normal grading. The highest unitsin the Kirk Creek section include dark .therefore the section isright way up. The epiclastic beds are grey to dark green plagioclase and coarse pyroxene-por- ,overlain abruptly bythe rhyolite flow (unit lmJHron Figures phyritic flows that form the resistant ridge (division D-4 on :2-12,2-13; division D-3 on Photo 2-18). Photo2-18).Flowsarethickerandepiclasticbedsareabsent in this part of the section, in contrast to division 2. Dark RHYOLITE (Unit ImJHr) green and lesser maroon, carbonate-cemented amygdaloidal Distinctive pink to brick-red weathering, hematitic olivine basalt pillow breccia (Photo2-19) and rare bioclastic Ilow-banded rhyolite overlies epiclastic rocks in the Kirk limestone lensescomprise the highestunit farther southeast, t3reekcirqueandoverliesandesiteflowswestofMountKirk north of Crocus Mountain. lunitlmJHronFigures2-12,2-13;division3onPhoto2-18). The uppermost Kirk Creek flows have clinopyroxene The crudely columnar jointed flow attains a maximum phenocrysts with smaller inclusions of phlogopite, indicat- thickness of 50 metres and was traced over 2 kilometres ing their high-potassium, alkaline affinity. Basalt flows along strike, making it an important local marker (Figure north of Crocus Mountain contain olivine (about 5%) altered ;!-12). Noahwest-striking flow banding varies in northeast to serpentine and chlorite, andveinlets and amygdules are dip between 20" and 50" and locally forms spectacularroot- filled with chlorite, albiteand calcite.

37 CHEMISTRY Twenty-one samples of flows and sills were analyzed for major and trace elements,with eight of these being discarded for classification purposes in accordance with the alteration screening criteriaset out in Appendix 9. The thir- teen relatively unaltered samples spana wide compositional range, including basaltic andesites, andesites, basaltic trachyandesites, trachyandesite, trachyte and rhyolite(Fig- ure 2-14a). The suite is dominantly subalkaline, with two samples from division 4 (unit 1mlHb) on the Kirk Creek section plotting in the alkaline field (Figure2-14c). All are calcalkaline on the AFM plot (Figure 2-14b). The broad compositional rangeand lackof rocks of shoshonitic affinity distinguish the Hazelton Group from Stuhini Group. A trace element spidergram of five of the most mafic samples, normalized to mid-ocean ridge basalt, exhibits a profile very similar to the Stuhini Group, but withslightly higher niobium and zirconium concentrations and a lower phosphorus spike (Figure2-l4e). The strong lithophile element enrichments are probably related to subduction in an arc setting (Pearce, 1983; Marsden and Thorkelson, 1992), while the slight niobium enrichmentandrelativeconcentra- tions of niobium, zirconium and yttrium establish a subtle within-plate signature (Pearce,1983). This suite plots above the oceanic-arc field on the Zrversus ZrN plot (Figure 2- 14d), with three samples in the within-plate field. These chemicalsignaturesarecompatiblewithavarietyoftectonic scenarios. In addition, the process of eruption through two older volcanic successions (Stikine assemblage and Stuhini Group) may havehad the effectof increasing incompatible element enrichments through crustal contamination. The

D-IV

~ D-Ill

D-ll

D-I

Photo 2-18. View northeast to nearly flat lying lava flows and volcaniclastic rocks characteristicofthe Jurassic succession (unit ImIHv), 3 kilometres southof Mount Kirk.The rhyolite flow(unit ImJHr) that was samplcd forU-Pb dating is identifiedas Site B. Paleomagnetic drill sites shown in the right-hand column are describedin Vandal1 et 01. (1992).

38 Geological Survey Branch Photo 2-19. Basalt fragment displaying bread-crust texture(unit ImJHb: DBR89-430). possibly a bomb. immediately northwest of Crocus Mountain.Most of the basalts found at the lop of the Hazelton succession are massive. discrimination among possible tectonic settings based on AGE AND CORRELATION the composition of rocks is therefore ambiguous. The age of the volcanic rocks is based on two zircon U-Pb dates. macrofossil ages, and on intrusiverelationships CONTACT RELATIONSHIPS BETWEEN with the Saffron pluton (Table 2-1). A U-Pb zircon age of JURASSIC AND TRIASSIC UNITS 185+7/-1 Ma, Toarcian (M.L. Bevier in Brown eta[.,1992~. In most places Lower to MiddleJurassic rocks rest with “Sample A”), from an andesite flow breccia (unit IdHv) angular unconformity on older rocks. The unconformity is constrains the age of this unit. A whole-rock K-AI date of particularly well exposed 3 kilometres southeast of Crocus 1486 Ma from an equivalent stratigraphic level. most Mountain, where the angular relationship between overly- likely is partially reset. A U-Pb zircon date of 175+4/-1 Ma, ing Jurassic tuffaceous rocks and underlying upper Norian Aalenian (W.C. McClelland in Brown ernl., 1992~.sample turbidites approaches 90”. Isolated limestone pods distrib- B), was obtained from pink flow-banded rhyolite (unit uted along the contact areinterpreted to represent remnants IdHr) where a whole-rock K-AI date of l66*6 Ma from an andesite directly above the rhyolite is reset, and not sur- of Triassic limestones. The unconfotmity is locally marked prisingly, is concordant with K-Ar dates obtained from the by a maroon polymictic boulder conglomerate. west of Saffron pluton. A third sample of flow-banded dacite (unit Mount Kirk (Photo 2-20) and east-southeast of Crocus ImJHd; sample C on Figures 2-12.2-13) yielded an indeter- Mountain. Relief on the unconformity is variable (Photos minate U-Pb date(J.K. Mortensen, written communication, 2-15: 2-16), but locally appears lo be as much as 500 metres 1992). Biotite from granite and hornblende from quartz over short (IO00 m) distances (Photo 2-14). Northeast of monzodiorite of the Saffron pluton yield concordant K-AI Yehiniko Lake, maroon tuff and minor tuffaceous grit rest ages of 162k7 Ma (localities I and 11, Figure 2-12). nonconfotmably on theNightout pluton. The schematic relationship is shownin Figure 2-15, Ammonite fragments, belemnites, brachiopods and scarce bivalves from three new fossil localities have been An angular unconfotmity between moderate to steeply assigned Toarcian ages (H.W. Tipper in Appendix I). Prior dipping Stuhini Group volcanic rocks and gently dipping to this study, fossils from one locality near MountKirk were Lower Jurassic (Logan andDrobe, 1993a) polymictic con- interpreted to be Jurassic by Kerr (locality F28 of Kerr, glomerate is exposed along theeastern edge of the map area. 1948a) and his locality F29 may be within the same unit.

Bullelin 95 39 British Columbia

Photo 2-20. Lower Jurassic tuff-breccia (unitImlHv) supporting accidental lithic fragmentsof bladed-plagioclase porphyritic basalt (probably fromunit uTSv-p), north of Helveker Crcck (CGR89-173).

Stikine Arch

SUSTUT GROUP NIGHTOUT PLUTON \ Unconforrnity Late Triassic SAFFRON PLUTON STUHlNlGROUP Isillstones) Middle Jurassic UpperNorian HAZELTONGROUP STUHlNl GROUP (volcanicsl ToarcIan lo Aalenian Nortan or oldsr

Figure 2-15. Schematic diagram illustrates unconformable relationships between the Upper Triassic SNhini Group, Jurassic Hazelton Group and Upper Cretaceous to PaleoceneSustut Group, and their relation to the Late Triassic Nightout and Middle Jurassic plutons. Rocks of the Hazeltun outlierare intruded by the Saffron pluton whichis in turn unconformably overlain by conglomerateof the Sustut Group. ?he% relationships are similar to that for the Stikine Arch about100 kilometres to the east (cf Tbomson et al.,1986).

40 Geological Survey Branch Based on lithologyand age, the limy wacke(unit UHs) cor- UPPER CRETACEOUS(?)TO relates with the lower memberof Salmon RiverFormation, PALEOCENE SUSTUTGROUP (Unit KTS) of Anderson and Thorkelson(1990). in the lskut River area, Coarse-grained clastic and subordinate fine-grained and overlying stratawith the upper member. tuffaceous rocks, correlated on a lithologic basis with the Brothers Peak Formation of the Sustut Group (Souther, DEPOSITIONAL ENVIRONMENT 1972: Eisbacher, 1974), are exposed in a belt that trends northwest from nearYehinikoLake toMountHelveker, and Rapid facies changes within the Hazelton Group sug- in outliers southwest of the belt at MountKirk and Strata gest that subaerial and marine deposition were contempora- Mountain (Figure 2-16; Photo 2-21). At Mount Helveker, a neous. For example, on the ridge 1.5 kilometres north of nearly complete section is up to 500 metres thick. Kerr Strata Mountain, a southwest to northeast facies transition (1948a) mentions an exposure of the basal contact at this occurs between maroon(subaerial) andesite flows andtuff- locality but it was not found. Most of Yehiniko valley ap- breccia, and pale green (subaqueous) andesiteash and dust pears to be underlain by Sustut Group sediments, but they are poorly exposed. Prior to Quaternary lateor Tertiary ero- tuff, green andesite flowswith interbedded dark green silt- sion, the group would have formed a continuous unit, from stone and arkosic greywacke containing belemnites, bi- Strata Mountain to Yehiniko Creek (Figure 2-16), forming valves and rare ammonites. In turn, the marine rocksgrade a basin at least20 kilometres wide. vertically and laterally (farther to the northeast) into maroon Very poorly indurated, matrix-supported polymictic tuff-breccia. This suggests that contemporaneous subaerial cobble to boulder conglomerate, in places resembling Qua- and marine deposition occurred in an emergent island set- ternary glaciofluvial deposits, characterizethe Sustut Group ting. The flow-banded rhyolite and maroon andesite flow in the project area.Feldspathic greywacke, siltstone and rare shale and pale-coloured rhyolite tuff sub- tops and bottoms are interpreted as subaerial features. Over- conspicuous are ordinate. Basalt flows are rare. Brick-red, brown and grey all, subaerial rocks appearto dominate theJurassic package, conglomerates are massive tomoderately well bedded and but marine rocks are also exposed southeastof Strata Moun- locally contain crossbeds and foreset beds (Photo 2-22). tain (argillite, siltstone, fossiliferous greywacke, carbonate- They are poorly sorted but clasts are well rounded, except cemented amygdaloidal basalt pillow-breccia and rare inYehinikoCreekvalley.whereclasts,locallyupto3metres bioclastic limestone lenses), north of Mount Kirk (mauve in diameter, vary from well rounded to subangular. Clasts are derived from olderstratified and plutonic rocks, and on lapilli tuff with limestone lenses) and northwest of Mount Mount Kirk include distinctive pink flow-handed rhyolite Kirk (green, carbonate-cemented arenaceous sandstone, derived from immediately underlying Aalenian volcanic siltstone andpolymictic cobble conglomerate, and pale grey rocks. The conspicuous white bull quartz clasts(up to IO%) massive limestone). are of unknown provenance. Granitic clasts resemble Ye- sw

Photo 2-21. View northwestto Strata Mountain which comprises Sustut Group conglomerate and sandstone(unit KTS) unconformably (deposited on altered Lower to Middle Jurassic volcanic (unit rocks ImJHv) and Middle Jurassic(?)dikes. The light coloured areas below ,!he unconfonnity are limonitic, altered volcanic rocks and dikes.

.Bulletin 95 41 Brirish Columbia

Photo 2-22 (b).

42 Geological Survey Branch Photo 2-22. 'Qpical conglomerates that dominate the Upper Cretaceous to Paloecene Sustut Group in the Mount Helveker and Yehiniko valley area: (a) View nonheast to medium to thick-bedded polymictic conglomerate (unit KTS) with rare interbeds of rhyolite tuff,on north flankof Mount Hclvekcr.Foreset beds in centre of photograph indicate northto northeast palcocunents. Narrow dacite and basalt dikes, feeders to overlying Sloko volcanic rocks, cut conglomerate.(b) Polymictic conglomerate inuuded by basalt dikes on the southern flank of Mount Helveker (DBR89-3). (c) Typical poorly sorted, poorly indurated, matrix-supported polymictic conglomerate showing weak imbrication of clasts, southeast flankof Mount Helveker.

,,3' 30' 131' 20

Figure 2-16. Distribution of Sustut Group, paleocurrent directions and age constraints.The key areas discussed in text are indicated.A = 4B.8+3.7 Ma hornblende K-Ar date; B = 51.621.8 Ma wholc-rock K-AI date; C = 85.6G.O Ma biotite K-AI date; D = Paleocene pdymorphs. Photo 2-23. View southeastto bedded Sustut Group conglomerate (unitKTS) with a prominent layer of white rhyolite tuff (subunitt; DBR89-24area; see Figure 2- 17 for detailed stratigraphy).

Figure 2-17. Schematic sketch of key exposure of the Sustut Group northwestof Yehiniko Lake, locationC on Figure 2-16 (see Photo 2-23).

44 Geological Survey Branch Ministry of Employment and hveshcnr hiniko, Saffron and Sawback plutons.If clasts of the Saw- fine grained relict glass shards,quartz and lithic fragments. back plutonare present, it restricts the age range theof con- Fine-grained hornblende dacite flows(or sills) and maroon glomerates to post-Eocene. Clasts are commonly plagioclase crystal lithic tuff are locally present. Basalt surrounded by a rim of maroon. oxidized material. Coaly dikes, believed tobe feeders to younger flows, cut the con- plant stems, deciduous leaves and wood fragments occur glomerate and displayred and maroon reaction fronts upto locally. Sandstone lenses and beds are buff, brown, pale 2 metres from their contacts. green, grey, maroon and olive, and locally contain freshbi- The headwaters of Hallas Creek are underlainby red Lo otite. Thin but prominent, white, mauve and pale green,bi- brick-red, poorly sorted polymictic conglomerate,both ma- otitequartz-eyerhyolitetorhyodaciteashtolapillituffunits, trix and clast supported. Imbricated clasts indicate an east- up to 10 metres thick and locally welded, are in places in- northeast paleocurrent direction. Midway down Hallas terbedded with conglomerate (Photo 2-23; Figure2-17). Creek, well bedded greywacke withrare coalified tree trunk Sustut Group rocks on Strata Mountain, so named for fragments, and columnar jointed rhyodacite flows andtuff its prominent horizontal beds of laterally continuous, mas- overlie deposits of coarse angular volcanic fragments sup- sive to thick bedded greywacke and polymictic conglomer- ported in a muddy matrix; fragments are up to 3 metres in ate, have slightly different characteristics fromwest to east. diameter. The deposits are interpreted to be debris flows. 'The western facies, forming a rugged ridge, is more resis- Four kilometres farther to thenorthwest, in Arrival Creek, 'tant, thick to medium-bedded, dull brown weathering, dull green plagioclase-porphyritic andesite flowsand biotite coarsegreywacke and cobbleconglomerate, withraredacite quartz crystal lithic rhyolite tuff are interbedded with po- :sills and/or flows. The basal beds were described by Kerr lymictic cobble conglomerate. Weakly welded crystal mi- (1948a) as red sandstone and arenaceous shale depositedon otite, plagioclase, quartz) vitric tuff contains relict glass ;a strongly weathered red erosional surface, possibly a pre- shards. :served regolith. The eastern facies, forming a rounded ridge Northwest of Yehiniko Lake, the Sustut Group sedi- Iprofile, is coarser, poorly indurated. maroon, matrix-sup- ments are well exposedin two parallel gullies (Photo2-23; ported cobble conglomerate. According to Kerr and in ac- Figure 2-17). The steeply northeast dipping succession com- cord with our observations, the lower beds are dominated prises red to maroon, polymictic cobble conglomerateand by Stikine assemblage pebbles. whereasthe top of the sec- breccia overlain by buff-weathering, coarse sandstone and lion is largely plutonic material. maroon conglomeratelbreccia. Buff-weathering greywacke The Kirk Mountain outlier is dominated by maroon, and cobble conglomerate are thick-bedded, laterally con- matrix-supported cobble toboulder conglomerate. Polymic- tinuous depositswith graded bedding that indicatesthe suc- tic conglomerate contains unique pink, flow-banded rhy- cession is rightway up. olite clasts derived from immediately underlying Hazelton 'hokilometres to the northwest, clastimbrication sug- Group rocks. Its southeast flank is cut by plagioclase-por- gests paleocurrents were to the northeast. Here, the sed- phyritic dacite dikes. ments are also predominantly matrix-supported,dull brown, TheMount Helvekersection comprisesa lowermaroon cobble to boulder conglomerate withrare pebbly sandstone to mauve, volcanic-rich cobble conglomerate overlain by interbeds. Clasts,in order of abundance, are biotite granite, buff weathering conglomerate with predominant plutonic green andesite,maroon plagioclase-porphyritic andesite,bi- clasts (SaIat and Noakes, 1979). Conglomerates are poorly otite hornblende granodiorite, foliated hornblende diorite, sorted, poorly indurated, massive to medium-bedded and basalt and rare siltstone andquartz. Dacite clasts, lithologi- matrix supported. The lower conglomerate contains clasts cally and texturally similarto flows and sills within Sus-the ofvolcanic rocks, with lesser plutonic,quartz and sedimen- tut Group itself, are also present. A light grey to pale green tary rocks. Clasts in the upper conglomerate are hornblende dacite lapilli tuff unit, up to 5 metres thick, lies between biotite granodiorite, hornblende biotite granite, pinkpotas- cobble conglomerate beds. sium feldspar megacrystic granite (totalling approximately 85%). with the remainder comprising volcanic rocks, feld- CHEMISTRY spathic greywacke and siltstone. The megacrystic granite Geochemical analyses for two possible flowsand a vol- clasts resemble Eocene granite fromthe Coast Belt. In gen- caniclastic sample are tabulated in Appendix 8. Only one eral the section is a poorly sorted, coarsening-upward se- unaltered flow samplewas plotted on Figure 2-18 together quence with low-angle bedding, indicatedby discontinuous with samples of SlokoGroup and Miocene basalt.It falls on feldspathic greywacke lenses. Bedding steepensto over 75" the border of the andesiteand basaltic andesite fields (Figure on the north flank of the mountain.A northeast-directed pa- 2-18a).Itisacalcalkaline,subalkalinerockontheAFMand leocurrent is presumed,however, this is based ononly a few alkali-silica plots (Figures 2-18c and b), and plots in the measurements of imbricated clasts and foreset beds. Salat within-plate fieldon the Zr versus ZrN plot (Figure 2-18d). and Noakes (1979) also indicate an east-northeast paleocurrent direction in both basal and upper conglomerate units. CONTACT RELATIONSHIPS Local greywacke beds display eroded channels filled with The Sustut Group rests with angular unconformity on cobble conglomerate. Chalky white to greenish grey, flaggya pediment of Upper Triassic and Lower Jurassic volcanic and friable crystal vibic rhyolite ash tuff beds, less than 4 rocks on Strata Mountain and Mount Helveker and on metres thick but laterally continuous,are preserved between Lower Jurassic volcanicrocks on Mount Kirk (Photo 2-24; cobble conglomerate beds. The tuff contains fresh, black Figures 2-15. 2-16). An irregular, ankeritic or iron-manga- blotite crystal fragments, aligned parallel to bedding, very nese oxide weathered surface is described by Salat and

Btrllerin 95 45 Calcalkaline Na20 u+ K20 MgO

+6 Alkaline 0,6

2 g40 Subalkaline , , 35 40 45 50 6560 55 70 75 80 05 ;:I//,Si02 (wt %) 1

Figure 2-18. Major and trace element geochemical plots for Sustut Group (circles), Sloko Group (triangles) and Miocene(?) volcanics (squares): (a)plotoftotal alkaliversus silica(afterLe Maitre, 1989). Pc=picmbasalt;F=foidite; Ul=tephritemasanite;U2=phonotephrite; U3=tepbriphonolite; Ph=phonolite; B=basalt; Sl=lrachybasalt; S2=basalric uachyandesite; S3=lrachyandesite;T=lrachyte/trachydaciIe; Okbasaltic andesite; Okandesite; 03=dacite; R=rhyolite; (b) plotof total alkaliversus silica (afterbine and Baragar, 1971); (c) AFM plot (after Imineand Baragar, 1971); (d) plot of log (ZrN)versus log Zr (after Pearce andNow, 1979). Pearce (1983) uses this diagram to distinguish arc volcanics erupted on oceanic crust from those eruptedon continental crust, with continentalarcs above ZrN = 3.

,, , i - . ., .-. Noakes on thenorth flank of Mount Helveker. The . , a', ,. (1979) .. , . ., ,, , , ~ >-- , ., ,,... .. ' ~ estimated total stratigraphicthickness varies from 300 to 700 metres from the south to north flank of the mountain. The depositional surfaceas exposed on Strata Mountain is essentially flat from east to west (i.e. mature). The basal contact is 350 to 450 metres higher in elevation at Strata MountainthanonthesouthernflankofMountHelveker(7.5 krn farther north); the present slope of the basal contact is about 3". Fast of Yehiniko Lake, subhorizontal conglomerate rests unconformablyon theNightout pluton. Northeast of Yehiniko lake, Sustut Group sedimentary rocks are in contactwith altered intrusiverocks and Hazei- Photo 2-24. View northwest to Sloko volcanic rocks (unit TS) capping Mount Helveker. Uranium-beating coalified wwd frag- ton volcanic rocks. Northwest of Yehiniko Lake, steeply men6 located in Sustutconglomerate (unit KTS), cropout in the northeast Strata Of the Sustut Group are inferredIo snow-filled -,mllv. Basalt dikes. feeders to the Sloko Gmuo... can be be faulted against the Yehiniko Pluton. In the Mount seencuttingtheSustutGroupconglomerarenearthebreakinslope Helvekerarea, basaltand felsite dikes, believed to be Sloko (see Photo 2-22b). Group feeders, intrude the sedimentswith striking thermal

46 Geological Survey Branch Ministry ofEmploymenf and Invesfmenf effects; conglomerate up to 2 metres from the basalt dikes and adjacent to the fans. The progression from volcanic to is red and oxidized (Photo2-22a). Sloko Group weldedtuff plutonic-dominated clast compositionsin conglomerates at sits unconformably on limonitic Sustut conglomerate. Mount Helveker suggests initial erosion of Mesozoic volcanic strata and subsequently their relatedplutons, as advo- AGE AND CORRELATION cated by Kerr (1948a). The large clast sizes and coarse Palynomorphs, extracted from a sample collectedkil- 4 greywacke interbeds indicate most of the sediments accu- ometres east ofthe map boundary, suggest an Early Paleo- mulated in the proximal alluvial fan facies.The red to ma- cene age, which is younger than the Brothers Peak roon clast rims signify subaerial deposition. Formation in its type area (Appendix 7). An additional ten Regionally, the deposition of the coarse clastic blanket samples were processed for palynomorphs but wereunpro- suggests a tectonic event (development of the Coast Belt) ductive. Fossil leaves of Aspidiophyllum trilobatum col- that uplifted Stikine Terraneto the west (present Coast Belt), lected from exposures of possibly correlative strata 28 eroded older strata and plutons, formed a major erosional kilometres northeast of Mount Helveker, on Kunishina surface, and deposited coarse clastic material in the map Creek, suggest a Late Cretaceousage (Kerr, 1948a). A Late area. The sediments represent late to postorogenic intermon- Cretaceous biotiteK-Ar date of 85.6d.0 Ma (Table 2-1) for tane molasse deposition (Miall, 1978). in a basin that may a biotite-bearing wacke supports the Brothers Peak Forma- have been related to strike-slip faulting in either compres- tion correlation (sensu stricto). However, the biotite flakes sional or tensional stress regimes, basedon plate models for have two possible sources:the Middle Jurassic Saffronplu- the Cordillera in Late Cretaceous to Paleocene time ton, or a primary volcanic origin.The unaltered crystalssug- (Gabrielse, 1985). The preservation and distribution of the gest a volcanic origin ratherthan erosion from a pluton and sediments mimics those at the mouth of Mess Creek therefore the date is interpreted to reflect the time of depo- (Souther, 1972) and southwest of the Grand Canyon of the sition of the wacke. An Eocene whole-rock K-Ar date of Stikine River (Read, 1983,1984). If this correlation is cor- 51.6t1.8 Ma was obtained from biotite-bearing vitric rhy- rect, then it implies that there was significant transtension olite ashtuff (Table 2-11, The dateis younger than expected, west of the right-lateral related strain documented by and may be the age of zeolite grade metamorphismrelated Gabrielse (1985) for the DeaseLake area. to Sloko Group volcanism. Eisbacher (1974) advocatedthat the Brothers Peak deposition continued theinto Eocene after ‘obtaining similarK-Ar results, however, these ages arein- EOCENE SLOKO GROUP (Unit TS) terpreted here to be reset. If they represent depositionalages, Eocene stratified rocks in the map area are charac- ,then the rocks are correlative with Eocene sedimentary terized by chalky white, poorly indurated intermediatetuff, rocks of the “Tanzilla Canyon formation” exposed near exposed only nearthe summit of Mount Helveker (Figures ‘Tuya River and Tanzilla Canyon (Read, 1984), and would 2-19, 2-20; Photo 2-24). The well exposed section is be- be tentatively assigned tothe Sifton assemblage (Gabrielse tween 150 and 275 metres thickand comprises a basal,gen- (et ai., 1991b). Souther (1972) included beds at the summit tly dipping welded dacite tuff and breccia, overlain by of Strata Mountain with the Sloko Group because of the porphyritic basaltic andesite flows(or sills ?)and capped by ]presenceof primary felsic volcanic material. However,it is hornblende-rich andesite breccia. ]now apparent that these rocks are correlative the with Sustut (Group, as originally advocated by Kerr (1948a). As pres- The basal white, grey and pale green, quartz-biotite ently interpreted, isit unlikely that someof the granitic clasts crystal ash to lapilli dacite tuffs and ignimbrite are both are derived from plutons as young as Eocene; however, welded and unwelded. Locally, prominenteutaxitic textures closer examination of the clasts and U-Pb dating could con- are defined by flattened fiammC. Individual cooling units lirm this. are difficult to define. Intercalated pale green plagioclase- porphyritic dacite flows and flow breccias have irregular DEPOSITIONAL ENVIRONMENT fractures and are locally columnarjointed.On the west side A high-energy alluvialfan setting with rapid sediment of Mount Helveker, welded tuff is overlainby brick-red vol- input from areas ofhigh relief is envisioned for the Sustut canic breccia and well bedded lithic lapilli tuff, interpreted Group. A system of coalescing alluvial fans, and probably to be pyroclastic surge and flow deposits. They are overlain braided streams, received intermittent pyroclastic deposits by light grey weathering hornblendeand plagioclase-phyric and rare flows. Itis inferred that a transverse drainage sys- dacite flows and sills. Lithologically similar dikes cut Sustut Group rocks on Mount Kirk, tem was developed, where streams flowed directly fromthe 6 kilometres to the southwest. uplifted source (Miall, 1981).The laterally continuous.thin Overlying the dacite flows near the top of the south luhite tuff horizons are believedto be episodic airfall depos- side of Mount Helvekerare distinctive dullbrown weather- its, preserved due to rapid burial by prograding alluvialfan ing, resistant. columnar jointed, pyroxene-plagioclase-por- sediments. The basin may have ken fault controlled,as are phyritic andesite flows and monolithic flow breccia. The numerous modem alluvial fans (Miall, 1981). Imbricated cumulative thicknessof the subhorizontal flowsis about 75 clasts and foreset bedsat several localities suggestnorth to metres, individual flows or sills are 2 to 5 metres thick northeastward-directed paleocurrents, in accord with Kerr’s (Photo 2-25). The top of Mount Helveker is capped by (1948a) observation that clast size decreases to the north- poorly indurated, recessive, light grey, pale to olive-green east. Fossilwood fragments and deciduous leaf imprints in- weathering, andesitic volcanic brecciaand homblendecrys- dicate vegetated areas in a temperate climate, probably on tal lithic lapilli tuff. Hornblende crystals in the matrix and

- Bulletin 95 47 ...... ,., .... /

.... ,...... ' 0- 1 km aTrachyandesite to basaitflowsls~lis 1Ahyodacite lapilli tuff-breccia,tufi

Figure 2-19. Distribution of Sloko volcanic rocks at Mount Helveker. Star depicts K-Ar sample locality. i

Figure 2-20. Schematic SIC.. Group stratigraphic column basedon the erosional remnant preserved at Mount Helveker. Samplenumbers correspond 10 lithogeochemical samplesin Appendix 8. Progression of Sloko Group volcanism at Mount Helveker is indicated by stages 1 to 3. lithic fragments are unaltered, however, plagioclase grains kaline, calcalkaline affinities (Figure 2-lXb, c). Two of the andthe matrixare clay-altered (Photo 2-26). moremafic samplesplot in thewithin-plate field on the Zr versus Zrly plot (Figure2-18d). CHEMISTRY On Mount Helveker, the lowermost daciticto andesitic Nine chemical analyses of Sloko rocks aregiven in Ap- unit (stage 1: Figure 2-20) includes a basal trachytic or pendix X, with two altered samples and one volcaniclastic trachydacitic ash tuff. The middle unit (stage 2) is mainly sample being discarded from the suite used for chemical andesitic, with one dacite sample and one basaltictrachyan- classification. The six remaining samples include rocks of desite. The andesitic rocks cluster near the boundary of the andesitic todacitic compositions(Figure 2-1Xa), with suhal- trachyandesite field, and may be characterized as medium

48 Geological Survey Branch Ministry of Employment and Investment

- hiletin 95 49 British Columbia

Photo 2-26. The top of Mount Helveker is andesitic hornblende-rich crystal lithic lapilli tuff-breccia (includedin unit TSd), from which an Eocene K-Ardale was obtained(DBR89-371; Appendix 3-2).

Photo 2-27. New southeast to flat-lying. columnarjointed basalt flow (unit Mb), ahout6 metres thick, 1.6 kilometres south of Latimer Lake.The undated flows are tentatively correlated with the Level Mountain flood basalts.

50 Geological Survey Branch Ministry of Employment and Investment

to high-potassium andesites. The upper hornblende-rich CHEMISTRY crystal lithic tuff-breccia (stage 3) is trachytic or trachydaci- Three individual flow sampleswere collected from the tic in composition. same outcrop for chemical characterization of this unit. One Overall there is a subtle angular discordance (10”) be- sample with a loss on ignition value greater than 4% was tween essentially flat-lying Sloko Groupvolcanic rocks and discarded. The flow is andesitic and hascalcalkaline, subal- underlying weathered, limonitic, gently dipping Sustut kaline affinities (Figures 2-18a. b. c). Chrome values are an Group conglomerate (Photo 2-24), however, beds are lo- order of magnitude greater than those from andesitesof the cally conformable. Hazelton, Sustut and Sloko groups. The Zr versus ZrN plot shows a trend toward higher ZrN values from Sloko and AGE ANDCORRELATION Sustut Groupsto the Miocene (?) volcanics (Figure 2-18d), with the latter displayinga strong within-plate signature. Kerr (1948a) referred to theserocks as “Helveker vol- Neogene volcanism in the Stikine belt includes both canics” (which he believed were Late Cretaceous; his unit alkaline basalt and peralkaline sialic suites. which occur in 1). Souther (1972)first correlated the rocks with the Eocene en echelon segments controlled by extensional structures. Sloko Group (his unit 24). New K-Ar dates reported here The controlling structures may be wrench faults related to indicate Sloko Groupvolcanism was coeval with Coast Belt larger scale dextral transcurrent structures (Souther, 1992). plutonism in the map area. Fresh hornblende crystals from grey to olive lithic fragments and matrix yielded a K-Ar date AGE ANDCORRELATION of 48.8e1.7 Ma 2-26). There are no (Table 2-1; Photo The Latimer Lake flowsmay be correlativewith flows events recognized in the area, andthis re- younger thermal 20 kilometres to the east, where basalt remnants derived sult is consideredan extrusiveage. Regionally the ageof the from the Mount Edziza area rest on river gravels in the group ranges from 45 to 55 Ma (Souther, 1977; Lambert, 1974). StikineRiver valley (Kerr, 1948a; Souther, 1972, 1992). Al- ternatively. they may correlate with flows that emanate from LevelMountain,ashieldvolcano33kilometrestothenorth- DEPOSITIONAL ENVIRONMENT northwest(Hamilton,1981).ThesourceoftheLatimerLake The basal contactof the Sloko Group with the Sustut flows is unknown and they remain undated. Group marks a change from high-energy, alluvial fan and fluvial deposition with minor intermittent rhyolitic volcan- QUATERNARY (UnitQal) ism, to extensive, explosive subaerial dacitic to andesitic Examination of Quaternary features was not the focus volcanism. The combination of lava flows and pyroclastic of the project but some relevant observations areincluded flows suggests Mount Helveker was close to a composite here to stimulate further research. Orientation of glacial volcano, but notdirectly within the vent facies, as most tuf- striations suggestsat least three episodes of ice transport in faceous material is lapilli to ash size. Exposures are rem- the Tahltan Lake map area. A north-northwest or south- nants of what must have been a much more extensive southeast ice movement above 1300 metres elevation con- volcanic pile. More extensive erosionalremnants. preserved tram with a north-northeast direction evident over the within grabens, occurto the northwest in the Tulsequah map lower, rolling hills west of Shakes Lake. Luge granite er- area (Souther, 1971; Bradford andBrown, 1993b). ratics, similar to the Sawback pluton to the south, lie on a plateau at 1700 metres elevation and are probably the prod- MIOCENE OR YOUNGER(?) FLOWS uct of this northeasterly directed ice movement.In addition, Sustut Group polymictic conglomerate boulders occur on (Unit Mb) Isolation Mountain (DBR91-245) andassuming their source Previously unmapped, flat-lying columnar jointed po- was the Strata Mountain - Yehiniko Valley area, then ice tassic andesite flows form isolated, cliff-face exposures movement must have been to thenorth. In contrast, erratics (Photo 2-27) and benches in a densely forested area 1.6 kil- south of Tahltan Lake, at loo0 metres elevation, point to a ometres south of Latimer Lake. The brown-weathering, period of southward-directed ice movement. amygdaloidal flows contain unaltered biotite and clinopy- Broad. U-shaped glaciated valleys commonly display roxene phenocrysts set in a groundmass containing green- misfit drainages, such as along the upper reaches of the brown plagioclase microlites. Amphibole and Tahltan River, and demonstrate how Pleistoceneglaciation clinopyroxene also occur as xenocrysts. Amygdules of in- has partially controlled the present drainagesystem. Clearly, tergrown quartz and calcite comprise 10%of the rock. The more work is required to resolve the timing and limits of series of flows, over 330 metres thick, is intermittently ex- each ice advanceand its Quaternarydeposits. A study of the posed from 670 to 1000 metres elevation. Individual flows Quaternary geology and climate change of Mount Edziza are 4 to 6 metres thick. Local red-brown interflow conglom- and Telegraph Creek area has recently been completed by erate suggestsfluvial reworking of some lavaflows. Spner(1994).

Bulletin 95 51 Ministry of Employmen1 and Invesmnt

52 Geological Survey Branch Ministry of Employment and Investment

CHAPTER 3 INTRUSIVE ROCKS

REGIONAL OVERVIEW The ForrestKerr pluton, southeast of the project area, Plutonic rocks ofnorthern British Columbia represent is the only known representative of the oldest suite; it in- at least seven intrusive episodes:Late Devonian, Middle(?) trudes Devonian strata and is overlain nonconformably by to LateTriassic, Late Triassic, Early Jurassic, late Early Ju- Early Carboniferous limestone (Logan et ai., 1993~;Drobe rassic, Middle Jurassic, and Eocene (Figure 3-1; Anderson, erai., 1992). Middle(?) to Late Triassic plutons fall into two 1993; Bevier and Anderson, 1991: Logan et ai., 1992a; groups: small, Alaskan-type ultramafic bodies and larger Woodsworth et ai., 1991). There are no known Cretaceous calcalkaline plutons. Both intruded at shallow levels and are plutons, which is in sharp contrastto the areas to thenorth coeval with Stuhini Group volcanism (Woodsworth et ai., near Atlin and south of Bowser Basin. Plutonic rocks related 1991). The ultramafic suite, known as the Polaris suite to individual episodes havebeen assigned to separatesuites. (Woodsworth er ai., 1991), includes the Gnat LakesCom- most of which are distinctive enough torecognized be at the plex (Nixon er ai., 1989). the Mount Hickman Ultramafic property scale. Complex and two smaller bodies discovered in the course of this study. However, new isotopic data for the Polaris

REGIONAL PLUTONICSUITES

Figure 3-1. Distribution of plutonic rocks, outlineof Bowser Basin andSkeena fold belt between Stewart and Rase Lake (modified from Wheeler and McFeely.1991). Selectcd plutons are labelled;details of the Stikine project area (outlined)are shown in Figure 3-2.

Bulletin 95 53 TABLE 3-1 CHARACTERISTICS OF INTRUSIVE ROCKS

Age/ nameAccessory Pluton type Rock Contact Plutonic Suite Minerals Relations Eoceneolder Intrudes(51-55all Mag Sawback, Tracegranite,Christina, Ma) Bio HYDER Hamper Bio granodiorite units Scud Pro. alt. granodiorite Intrudes granodiorite Tertiary alt. ?? Pro. Scud Stikine assem. MiddleJurassic (170-177 Ma) Yehiniko, SafFron, Hb-Bio granite Mag,Trace ti IntrudesStuhini Gp., N iko, Conover HazeltonTHREE SISTERSConover Niko, Gp. & Stikine suite Late Early JurassicStikinegranodioriteIntrudes Bio-Hb(180-187 Navo, Mtn., Cone Ma) Strata Glacier, assemblage & Dokdaon, Devils Copper Mtn. suite Mtn. CopperCONE Devils Dokdaon, MOUNTAIN Elbow, Jacksons, Strata Mtn., Shebou Early Jurassic Early (?) dioriteBio-Hb Ridge, Geology to StikineIntrudes N avo Qtz diorite asscmblage diorite DIORITE Qtz Navo & Copper Mtn. suite Intruded by Cone Mtn & Hyder suites Early Jurassic (189-195 Ma)IntrudesStikinemag. tracemonzonite Qtz Ti, Limpoke, Hb Poque, assemblage TEXAS CREEK Poque, & Brewery Stuhuni Gp. Pereleshin, Oksa Ck. LateTriassic to EarlyJurassic Rugged Mtn., Syenite, monzonite Gnt., Ti., apt.,mag. Intrudes Stikinc (210-195 Ma) Butterfly Quartz monzonite assemblagemonzonite Quartz Butterfly Ma) (210-195 & Stuhini COPPER MOUNTAlN GP. Latimer L., Bio mt apt. Ti, Damnation, clinopyroxenite MiddleLateTriassicto Hickman, Nightout, Hb-Bio granodioritemag.Py, Intrudes Polaris suite, (220-228 Ma) Castor,Lake,Tahltan to Qtzuncon. monzoniteGp., Stuhini STIKlNEHazclton by overlainLinle Tahltan Lake, Tahltan River, GP. Half Moon Middle toTriassic LatcMiddle ClinopyroneniteScud, 01, crmag., Intruded by M t. Hickman dunite Hickman pluton Hickman dunite HickmanALASKAN-TYPE Mt. ULTRAMAFITES Complex,

54 Geological Survey Branch Complex (Nixon et a!., 1993) suggestthat it isyounger than intrusions (Table 3-1). Composilionsofintrusiverocks were most of the ultramafic complexes in the project area which determined by examining hand specimens stained for potas- are referredto here as Alaskan-type ultramafic plutons. The sium feldspar and studying thin sections. Intrusive rocks Stikine calcalkaline suiteof plutons is the most extensive in were named using the classification schemesof Streckeisen the area. It includes the Stikine, Hotailuh. Hickman and (1976) and Le Maitre (1989). Whole-rock major and trace Mwsehom batholiths (Figure 3-1). Late Triassic to Early element analysesof 65 samples were used to classify rock Jurassic alkaline plutons of the Copper Mountain suite are types and discriminate among possible tectonic settings. commonly associated with porphyry copper-gold deposits Geochemical data and a description of analytical techniques throughout British Columbia (Woodsworth el al., 1991). are in Appendix 11. Table3-2 provides a summary of radio- The Rugged Mountain pluton and Butterfly pluton in the metric dates. Analytical data for new dates arein Appendi- study area and the Galore Creekintrusions immediately lo ces 12 and 13. AI1 previously published K-Ar isotopic dates the south, are correlative with the Copper Mountain suite. were recalculated using the decay constants of Steiger and Commonly, the plutons are bimodal, with ultramat% and Jager (1977); one sigma errors arereported. syenite phases.The Early Jurassic event,genetically related to important vein deposits in the Stewart-Iskut area, com- (?) prises the Texas Creek suitewith large, calcalkaline hetero- MIDDLE TO LATE TRIASSIC geneous plutons. Late Early Jurassic intrusions have been PLUTONS (228-220 Ma) added to these suitesbased on new data for the ConeMoun- Triassic plutons are well represented in the study area tain pluton. Middle Jurassic plutons are included in the and fall into two main groups: small, Alaskan-type ul- Three Sisters suite, described by Anderson (1983a,b). Ex- tramafic plutons, and more extensive tholeiitic to calcalka- tensive Eocene plutons of the Hydersuite commonly under- line diorite to granodiorite stocks. They correspondroughly lie the eastern pan of the Coast Belt. tothePolarisandStikinesuitesofWoodswonhelal.(1991). Plutonic rocks underlie about 40% (1500 km2) of the AUSKAN-TYPE ULTRAMAFITES map area, mainly in the south (Figure 3-2). Field relationships, compositional, mineralogical and textural data, com- Alaskan-type ultramafite bodies underlie MountHick- bined with radiometric dates, were used to define suitesof man, "Middle Scud" Creek, and an area southwest of Ye- hiniko Lake (Figure 3-3). They are typically dull brown to

Figure 3-2. Distribution of plutons in the project area, showing isotopic age determination sample localities. Figure 3-3. Distribution of the Middle to Late Triassic Stikine and Mount Hickman PlutonicSuites. -......

Brirish Columbia

TABLE 3-2 SUMMARY OF ISOTOPIC DATES FOR PLUTONIC ROCKS

FIELD MAP ROCK TYPE PLUTONIC PLUTON DATING MINERAL AGE REF.PLUTONICMINERALDATINGPLUTONAGE TYPE ROCK MAP FIELD N O. UNIT SUITE METHOD (Ma) METHOD SUITE UNIT NO.

DBR88-290-2 Fclsite Edike Dike Hyder K-Ar Bi 49.7 f 1.7 3a MGU88-48 GranodioriteEgd Christina Hyder K-Ar Bi 54.2 j. I .7 3a MGU88-48 GranodioriteEgd Christina Hyder K-Ar Hb 56.1 f 2.0 3a 0266-6 Egd Quam monzoniteChriStiM Hydcr K-Ar Bi 45.112 2 MGU88-76 Egn Biotite granite Hydcr Sawback K-Ar Bi 48.0 + 1.7 3a

CGR89-495 mlgn Granite Threc Sisters Saffron K-Ar Bi 162*7 3a CGR89-517 mlgn MoNodiorite Three Sisters Saffron K-Ar Hb 162j.7 3a 81-HA19a mlgn Qummonzonite Three Sisters Yehiniko Rb-Sr Bi 1701. I6 1 8l-HA19a dgn Quammonzonite Three Sistcn Yehiniko K-Ar Bi 172i6 1 8l-HAl9a dgn Quam monzonite Three Sisters Yehiniko Rb-Sr WR 178j.11 1 DBR88-328 dgd Pinkgranite Three Sisters Niko K-Ar Bi 177f7 3a CGR89-546 elm MoNonite Threc Sisters Conover K-Ar Hb 17716 3a

DBR90-40 Granodioritelelgd Cone Mtn. Cone Mm. U-Pb Zr 184.7 i 0.6 3c DBR88-331 lelgdGranodiorite Cone Mtn. Dokdaon K-Ar Hb 158*6 3a DBRKS-329 ldsd Granodiorite Cone Mm. NWO K-Ar Bi I63 i 6 3a DBR88-329 klgd Cranodiorirc Mtn.Cone NaYO K-AI Hb 182 * 7 3n

DBR91-723 MoNoniteeJm Texas Crcek Limpoke U-Pb Zr 19412 3c DBR91-723 eJm MoNonite Texas Creck Limpke K-AC Hb I82 f 5 3a MGU88-102 clqm Quam monzonite Texas Crcck Pcrelerhin K-Ar Hb 204f7 3a

INE91-119 ITSBi-cpa syenitc Coppcr Mtn. Ruggcd Mtn. Ar-Ar Bi 195 f 3 3b DBR91-725 syeniteITSBi Capper Mtn. Rugged Mm. U-Pb Zr >189.4 f 0.6 3d MGU90-743 ITSHornblende syenite Copper Mm. Buttemy Ar-Ar Hb 204.1*2.0 4

CGR89-78 MonzonitelTgd Nightout Stikine K-Ar Hb 200 i 7 3a 81-HAl7a ITgdHb-Bi granodiorite Stikine Nightout K-Ar Hb 22818 1 81-HA17a ITgdHb-Bi granodiorite Stikinc Nightout Rb-Sr Bi 232 + 5 1 81-HA17a lTgdHb-Bi granodiorite Stikine Nightout K-Ar Bi 23619 1 81-HAlOa 1TmBi-Hb granodiorite Stikine Hickman K-Ar Bi 209i15 1 81-HAlOa ITm Bi-Hbgranodiorite Stikine Hickman Rb-Sr Bi 216+4 1 81-HAlOa ITmBi-Hb granodiorite Stikine Hickman K-AI Hb 22118 1 81-HAlOa ITmBi-Hb granodiorite Hickman Stikine Rb-Sr WR 233 f 23 1

One sigma errors for K-Ar and Rb-Sr dates, andtwo sigma errors for U-Pb dates are reported, see Appendices 12 and 13 for analytical data. References: I = Holbek (1988); 2 = White ef al. (1968); 3 = this report, a = Harakal, b = Reynolds, c = McClelland, d = Mortenson); 4 = M.H. Gunning in Hunt and Roddick (1994, sample GSC94-41, pages 139-140).

56 Geological Survey Branch Minisrw ofEmpioymenr and Inveshenr black weathering, orthopyroxene-free clinopyroxenites The body displays faint magmatic layering developed in which contain abundant magnetite. They intrude andhorn- fine-grained, locally foliated. dull brown weathering cli- fels mafic metavolcanic hostrocks. The body at Mount nopyroxenite. Granodiorite dikes, believed to be related to Hickman has a dunite core and a clinopyroxenite margin, the Nightout pluton, cut the ultramafite. Anomalous nickel suggesting an Alaskan-type affinity (cf: Nixon and Rublee, and cobalt Regional Geochemical Surveyvalues in Saffron 1988). The ultramafites may be feeders to parts of the Creek may be derived fromthis body. Stuhini Group. Other ultramafic bodies are associatedwith megacrystic syenite and have been included in the younger HICKMAN BATHOLITH Copper Mountain suite. Collectively, the Stikine suite of plutons delineatesthe Stikine Arch. The north-trending Hickman batholith, about MOUNT HICKMAN COMPLEX 65 kilometres long by 17 kilometres wide, is the southem- The best exposed andstudied member of the Middle to most body of the suite. It underlies an area of about 1200 Late Triassic ultramafites is the Mount Hickman body, an square kilometres in the eastem part of the map area. The oblong, northeast-trending intrusion about 3 by 5 kilometres batholith is composed of three plutons: the Middle(?) to Late in surface area. This study represents the body as a distinct Triassic Hickman and Nightout plutons andthe Middle Ju- entity rather than includingit within the Hickmanpluton (cf: rassic Yehiniko pluton (Figure 3-1; Souther, 1972; Holbek, Souther, 1972). Detailed descriptions of the body are given 1988). Souther’s “Hickman batholith” isarestricted circular by Nixon et al. (1989). It comprises mainly medium- pluton east of Schaft Creek and north of Mount Hickman grained, equigranular, black to tan-weathering clinopy- and is now referred to as the Hickman pluton. TheTriassic roxenite and olivine clinopyroxenite containing IO to 15% plutons are believed to be subvolcanic intrusions of the fractured, serpentinized olivine and3 to 5% euhedral chro- Stuhini Group, as documented for the Hotailuh batholith mite and magnetite. Partof the core isa small dunite body (Anderson, 1983a). Locally, granitoid-bearingintravolcanic with serpentinized and fresh olivine. The body produces conglomerates indicate denudationof parts of these plutons prominent magnetic highs on aeromagnetic maps (Map during Stuhini Group volcanism. 92386: Map NTS 104G; Map NO-09”). The ultramafite intrudes and metamorphoses a roof HICKMAN PLUTON pendant of plagioclase-phyric andesite flows and tuffs cor- The Hickman pluton, consisting of three distinctive relative with the Camian to Norian Stuhini Group, but is phases, underlies an area of 300 square kilometres in the itself intruded by, and is found as xenoliths within, the main southern comer of the map arewearVanishing Lake. The phase of the Hickman pluton. The southwest contact of the heterogeneous main phase is the most extensive and is complex is homfelsed Stuhini volcanic rocks and therefore dominated by massive to faintly foliated, medium-grained, believed to be intrusive. A limonitic zone in this area may equigranular, dull grey hornblende biotite granodiorite to mark the northeastward extension of a fault mapped to the quartz monzodiorite. Tonalite and quartz diorite aresubor- south by Logan et al. (1993a). dinate and their relationship to themain body is uncertain. Magnetite and raretitanite are accessory minerals. The main MIDDLE SCUD ULTRAMAFITE phase intrudes themafic phase on the south,Stuhini Group The Middle Scud ultramafite, named after the creekto volcanic rocks and Mount Hickman complex on the east, the northwest, comprises a 4 square kilometre, variably ser- and Permian and Upper Triassic sediments on the west. Late pentinized, medium to fine-grained clinopyroxenite. It in- Triassic dates of 209?15 Ma (K-Ar biotite), 221+8 Ma (K- trudes mafic metavolcanic rocks (biotite schist) correlated Ar hornblende), 216k4 Ma(Rb-Sr biotite) and 233?23 Ma with the Stuhini Group. Anomalouslyhigh amphibolite fa- (Rb-Sr wholerock Holbek, 1988; Table 3-2) were obtained cies metamorphic grade attained by rocks in this area may, for the main phase east ofVanishing Lake. The main phase in part, be due to theemplacement of the ultramafic rocks. is lithologically similarand coeval with the Nightout pluton, The southeast corner of the ultramafite is intruded by a larger but locally more strongly foliated body exposed 10 megacrystic quartz diorite of the Hickman pluton. Serpen- kilometres to the north. tine-rich shears and north-trending faults cutthe ultramafite and extend north to the Yehiniko uluamafite. The Middle The mafic phase forms the southern border of the Scud and Yehiniko ultramafites lack the prominent aero- batholith and extends south into the areamapped by Logan magnetic signatureswhich characterize the Mount Hickman and Koyanagi (1989). It comprises medium-grained, equi- complex. granular, hornblende gabbro and plagioclase-bearing horn- blendite. The contact with the main phase is locally YEHINIKO ULTRAMAFITE gradational and mafic xenoliths are found within the main An ultramafic body southwest of Yehiniko Lake was phase. discovered duringthe course of this project. It sharesattrib- The diorite phasecomprises megacrystic quartz diorite utes of the Middle Scud body in that it liesalong north-trend- and underlies a 12 square kilometre areaon thewest margin ing faults, is sheared, is peripheral to a Late Triassic pluton, of theHickman pluton. The pluton outwardly resembles pa- and is difficultto distinguish from mafic metavolcanicrocks tassium feldspar megacrystic quartz monzonite of the Late correlated with the Stuhini Group. The high magnesia and Triassic to Early Jurassic Pereleshin pluton (see below). chrome oxide and low silica geochemical signature was However, as Souther (1972) noted. the rectangular used to distinquish this body from maficmetavolcanic rocks megacrysts, which are up to5 centimetres long, are plagio- of the adjacent Stuhini Group (Figure 3-10; Appendix 11). clase, not potassium feldspar. Quartz and hornblende,

~ Buliefin 95 57 chloritized biotite and accessory magnetite comprise the OTHER STIKINE SUITE PLUTONS groundmass tothe plagioclase megacrysts. Diorite intrudes Five undated plutons in the northern part of the map the Middle Scud ultramafite along its western contact; the area are tentativelyincluded in the Stikine suite:the Tahltan character of the eastern contact is uncertain. The diorite is Lake, Castor, Little Tahltan Lake, Tahltan River and Half spatially associated with the Hickman pluton and, at one Moon plutons (Figure 3-3). All are small (each less than 4 locality, has a poorly defined gradational contact with the km2) and intrude Stuhini Group rocks. They lie immediately main phase. At another locality, the diorite phase intrudes southeast of the extensive Moosehorn pluton which isbe- the mafic phase. These relationships indicate that it is lieved to be Late Triassic in age (cf Bradford and Brown, younger than the mafic phaseand possibly coeval with the 1993b). main phase. A prominent aeromagnetic anomaly that ex- The Tahltan Lake pluton underlies a3.5 square kilome- tends southalong the southwestborder of the Hickman plu- tre area immediately west of Tahltan Lake. Hornblende ton may outline the diorite phase. quartz monzodiorite dominatesin the northern and western NIGHTOUT PLUTON sectors of the intrusion, while the eastern half is characterized by hornblende quartz diorite. Though composition- The Nightout pluton (Holbek, 1988) underlies about ally varied, the fineto medium-grained, equigranularrocks 275 square kilomeh-es. Its distribution has been modified are texturally homogeneous. Poikilitic hornblende is rela- from that of previous workers (Souther, 1972; Holbek, tively unaltered and occurs as subhedral to euhedral pris- 1988) by including a phase north of Boomerang Creek matic grains which enclose equant plagioclase crystals. which had been grouped with the Yehiniko pluton. The plu- Colour index ranges from 18in the quartz monzodiorite to ton consists of foliated to massive, medium-grained, biotite 30 in the quartz diorite. Oscillatoryzoned plagioclase crys- hornblende granodiorite that grades locally to tonalite, tals are invariably saussuritized, giving a grey to greenish quartz monzonite, monzodiorite and diorite. Titanite is a cast to the rocks. Accessory minerals include magnetite, common, locally medium-grained accessorymineral. Mafic apatite and zircon. inclusions are common along the margins. Near Lingwell The Castorpluton is an eye-shaped, bimodalintrusion Creek, the pluton is characterized by a widespread mag- exposed over about 6 square kilometres southeastof Little matic foliation and by coarse-grained (up2 cm) to poikilitic Tahltan Lake. It is dominated by fine to medium-grained potassium feldspar grains. equigranular biotite hornblende granodiorite. Along the The Nightout pluton intrudes Stuhini mafic volcanic eastern margin, the border phaseis characterized by fine to rocks on its westand northwest margins, and foliated Stikine medium-grained hornblende quartz diorite;to the west it is assemblage rocks on its northern margin. Foliation in the represented by fine-grained equigranular tonalite. The col- pluton parallels the contactand the foliation in the country our index ranges fromIO to 30 and plagioclase is weaklyto rocks. In Yehiniko Creek canyon,Kerr (1948a) describeda moderately saussuritized. Potassium-feldspar megacrystic syenite felsenmeer associatedis with thewestern part of the thick sill-like geometry for the western part of the pluton pluton. which he referred to as the “Yehiniko mass” He suggested it wasthe source of arkosic sedimentaryrocks in Glomerate The Little Tahltan Lakeplutons comprise 4 square kil- Creek. Near the headwaters of Boomerang Creek, the ometres of predominantly medium-grained, inequigranular Nightout pluton is overlain nonconfomably by Lower Ju- hornblende granodiorite; most have medium to fine-grained rassic volcanic rocks of the Hazelton Group and by Upper quartz monzodiorite to hornblende diorite border phases. Cretaceous to Paleocene(?) conglomerate of the Sustut The colourindex of the intrusion directly northwestof Little Group. Along the southwest sideof Yehiniko Lake and far- Tahltan Lake ranges fromIO to 30.Hornblende is the domi- ther south, unfoliated, medium-grained equigranular mi- nant mafic mineral and accessory minerals include magnetite and titanite. Hornblende is altered chlorite and epidote otite) hornblende tonalite,possibly a marginal phase of the to while turbid, interlocking plagioclase laths and potassic Nightout pluton, intrudesand hornfelses the Stuhini Group feldspar crystals are completely replacedby carbonate and and the Yehiniko ultramafite. sericite. Thereis a poorly developed foliation withinthe in- Potassium-argon isotopic datesof 236s Ma (K-Ar bi- trusion along its western margin. otite), 228& Ma (K-Ar hornblende),and 232~5Ma (Rb-Sr The Tahltan River pluton is a narrow, elliptical body, biotite; Holbek, 1988; Table3-2) suggest a Middleto Late less than 2 square kilometres in area, that is poorly exposed Triassic age for the southern partthe pluton. of Farther north, along the banks of the Tahltan River northwest of Tahltan near Boomerang Creek, a sampleof biotite hornblende gra- Lake. It is a predominantly leucocratic(colour index = IO), nodiorite collected near the pre-Lower Jurassic unconfor- medium-grained equigranular hornblende to biotite horn- mity yielded a hornblende K-Ar date of 2@7 Ma (Table blende quartz monzodiorite. Hornblende, the dominant 3-2; Appendix12); this may be a partially reset age, perhapsmafic mineral, occasionallyenclosescrystalsofplagioclase. reset during intrusion of a nearby east-strikingdike swarm Quartz and potassic feldspar are interstitial. Alteration is possibly associated with the Middle Jurassic Saffron pluton.moderate, producing bleached,pale grey towhite-weather- However, in contrast to mostof the Nightout pluton to the ing outcrops. Hornblende is partially altered to chlorite; zeo- north, which isfoliated, the dated samplewascollected from lites are present along joint surfaces and quartz-epidote an unfoliated phase, which may be younger (Souther, 1972). veinlets are common.

58 Geological Survey Branch The Half Moon pluton is a 4 square kilometre, crescent-include Galore Creek, the Ten Mile Creek body (Morgan, shaped body outcroppingnorth of Tahltan River. The centre 19761, and the Zippa Mountain pluton (Bevierand Ander- of the pluton consists of equigranular medium to coarse- son. 1991; Lueck and Russell, 1994; Figure 3-1). The Ten gained hornblende quartz monzodiorite.The border phase Mile Creek intrusion has awell preserved clinopyroxenite is equigranular to inequigranular fine to medium-grained border phase around a syenite core. This complex yields hornblende biotite quartz diorite. Mafic mineral contents Late Triassic K-Ar dates [(209+7 Ma, recalculated from range from15 to 25%. Plagioclaseis saussuritized and chlo- datesofMorgan(1976)usingdecayconstantsofSteigerand rite alteration is pervasivethough weak. Jager (1977)l. Stevensel al. (1982) reportedan Early Juras- sic biotite K-Ar date of 202k7 Ma from a biotite clinopy- L.ATE TRIASSIC TO EARLY JURASSIC - roxenite of the Tahltan syenite stock in Stikine Canyon, COPPER MOUNTAIN PLUTONIC SUITE presumed tobe the same body as the Ten Mile Creekintru- (;!10-195 Ma) sion. The dominantly alkaline Copper Mountain suite con- BUTTERFLY PLUTON sists of small intrusionsand dikes (Figure 34) which range TheButtedy pluton. referredtoasthe “Butterfly Creek in composition from syeniteto quartz monzonite. They are mass” by Kerr (194Ka), intrudes Carboniferous volcanic commonly associated with copper-gold mineralization, as rocks of the Stikine assemblage and volcanic rocks of un- exemplified by the GaloreCreek deposit southof the study certain age, at Butterfly Lake. Detailed descriptions of the area. The Rugged Mountain pluton and Butterfly pluton pluton are provided by Gunning (1993a). The stock is an (Gunning. 1993a) best illustrate the characteristic features elongate body, less than 2 kilometres wideand 3 kilometres ol‘this suitein the project area,namely: abundant potassium long. The composite, multiphase body (4 phases) comprises feldspar megacrysts, aegirine-augite, biotite and melanite pyroxene-rich syenite inthe southwest, and potassium feld- gsunet (Neill. 1992; Neill and Russell, 1993). The alkaline spar megacrystic syenite to quartz monzonite in the north- intrusions and their commonly associated ultramafite east. The central part of the body is mainly hornblende phases tend to be magnetite rich and therefore produce syenite and lesser potassium feldspar megacrystic syenite. prominent aeromagnetic anomalies. Similar syenite stocks Black to darkgreen pyroxenite and pyroxene syenite isme- with marginal pyroxenite complexes occur regionally and dium to coarse grained, with abundant biotite, augite, hornblende and magnetite. Distinctive flow-aligned potassium feldspar megacrysts up to 5 centimetres long comprise up to 70% of orange-brown weathering syeniteto quartz monzonite. Epidotized and chloritized hornblende comprises less than 5% of the rock. Aegirine-augite, colourless garnet and biotite flakes were noted by Kern (1948a). Disseminated pyrite and magnetite are common accessory minerals.Tex- tures vary from coarse megacrystic to medium grained. Hornblende isthe dominant maficmineral in contrast topy- mxene in the older syenitephase. Hornblende syenite dikes with pyroxene syenite xenoliths intrude the megacrystic syenite. The eastern margin of the pluton is marked by chloritic metavolcanic phyllite and there is local biotite hornfels. Smallirregular bodies of hornblende quartz monzodiorite and diorite which intrude the syenite west and south of Bunertly Lake may be related to youngerplutonica episode. A buff-weathering, northeast-striking heterolithic intrusive syenite breccia dike intrudes siliceous siltstoneon the northeast side of Butterfly Lake. Another irregular intrusive breccia is exposed in the south-central part of the pluton. The breccias contain fragments of megacrystic syenite, and lesser green, grey and black siliceousrock, granitoids. rare aphanitic basalt fragmentsand potassium feldspar crystals in a dark green, chloritic groundmass. The Butterfly pluton is correlated with the Copper Mountain suite on the basisof megacrystic texture, mineralogy,~ornpositionanda204.1+2Mahomblende~Ar~~Ar age (Gunning, in Hunt and Roddick, 1994). RUGGED MOUNTAIN PLUTON Figure 3-4. Distribution of the Late Triassic toEarly Jurassic The aptly named Rugged Mountainpluton (Photo 3-1), Copper Mountain Plutonic Suite. exposed on the southernflank of Rugged Mountain, covers

- Bulletin 95 59 British Columbia

Photo 3-1. Mew norlheast to the Rugged Mountain syenite complex(z), dark mafic border phase (y) along the northern contact of the pluton, intrudes Stuhini Group rocks(x).

Photo 3-2. Late-phase trachytic potassium, feldspar megacrystic dikc of the Rugged Mountain complex.

60 Geological Survey Branch ~~

Minisrrv of Energ?: Mines and Petroleum Resources an areaof about 14 square kilometres. A detailed mapping, garnet. Pyroxene of variable compositions andapatite crys- petrographic and mineral chemistrystudy of the pluton by tals are subaligned and may represent cumulate minerals. Neill (1992) undertaken in conjunction with this project, Secondary minerals in fracture fillings includechlorite, cal- provides the basis formuch of the following description. cite and garnet. The pluton is a composite (3 phases and dikes), pink to SYENITE PHASE light grey alkaline syenite body, which intrudes Stuhini Group tuffaceous siltstone, shale, limestone and ash tuff. Pink, medium-grained alkali-feldspar syenite contain- The complex has a pyroxenite phase along its nonhernmar- ing less than 60% mafic minerals is the predominant phase gin and most contacts between syenite and pyroxenite are of the complex. Potassium feldspar occurs as interstitial sharp, but locally, an intrusive breccia is formed, with py- grains and locally as megacrysts up to 2 centimetres long. roxenite blocks in a syenite groundmass. This relationship Other primary minerals include melanite garnet, biotite, is similar to the Butterfly pluton. Late-phase, leucocratic. apatite, titanite and magnetite. Aegirine-augite commonly potassium feldsparmegacrystic dikes cutall phases and the occurs as small, fractured cores with secondary hornblende country rocks (Photo3-2). Kerr (1948a) referred to the com- rims. Primary hornblende is a minor component. plex as the "Shakes Creek mass". HYBRID PHASE Four main rock types were differentiated by Neill The hybrid phase has similar mineralogical features to (1992). based largely on mafic mineral content: clinopy- the syenite phase but contains more60% than pyroxene and roxenite, hybrid syenite and clinopyroxenite, syenite and biotite. The syenite and hybrid phases were not differenti- syenitelmonzonite dikes. All rock types contain potassium- ated on the map (in pocket). feldspar, biotite. aegirine-augite, melanite garnet, magnetite, titanite and apatite. Pyroxene is relatively unaltered but ALKALINE DIKE SWARM feldspars showsome sericite and chloritealteration. Garnet West-striking syenite dike swarms arewell exposed 1.5 occurs as dark red crystals and light brown grains surround- kilometres north and 4.0 kilometres southwest of Rugged ing other accessory minerals. The garnet is a high-titanium Mountain. The texturally variable dikes include both variety of andradite that typically occurs in soda-rich igne- trachytic to sub-trachytic potassium feldspar megacrystic ous rocks (Kerr, 1959). The $ybri$phase of the Rugged (up to 7 cm long) varities. and trachyticalbite-megacrystic Mountain complex yielded an Ar- Ar biotite plateau date varieties. Pyroxene is rare and, where present, is replaced of 195k3 Ma (P. Reynolds. written communication, 1993). by hornblende: otherwise the mineralogy is similar to the which is concordant with the Limpoke pluton of the Texas syenite phase. A potassium feldspar megacrystic dike on the Creek suite (Figure3-5; Table 3-21, west flank of Rugged Mountain yielded a im recise U-Pb CLINOPYROXENITE PHASE date, interpreted to be older than the 206U338Pb age of The partially prCSeNed biotite clinopyroxenite border 189.433.6 Ma (J.K. Mortensen, written communication, phase is upto 100 metres wide and 2.5 kilometres long. and 1994; Figure 3-5; Table 3-2). Dike swarms in Barrington River canyon and the eastern flank ofIsolation Mountain forms the steeply dipping northern contact of the complex on (Photo 3-1). The contact between pyroxenite and syenite is are possibly related. Together the dike swarmsradiate from sharp. The recessive pyroxenite weathers black to dark an area outlined by a prominent aeromagnetic anomaly cen- green and containsunaltered pyroxene and biotite. Smaller tredonLatimerLake,andmayberelatedtoablindinuusion. pyroxenite bodies have also been mapped along the northeast and southeast bordersof the pluton. LATIMER LAKE AND DAMNATIONPLUTONS Aegirine-augite. magnetite and apatite comprise the Discreteultramatite bodies withoutappreciablesyenite bulkoftherock, with lessertitanite, biotiteandraremelanite underlie the Latimer Lake and Damnation Creek areas(Fig- ure 3-4). They are included in the Copper Mountain suite because they have similar textures andcornpositions to clinopyroxenite phases of the suite. 195 Ma Bioiila Plaieou Oaio The three small ultramafic plutons, underlying less than v 7 square kilometres in total, intrude and hornfels Stuhini Group tuffaceous siltstone along an easterly trend, 4 kilometres nonh and east of Latimer Lake. Two of the intrusions had not been mapped previously. Their characteristics are well represented by the Latimer Lake pluton, which underlies a forested area and is poorly exposed. Partially caved bulldozer trenches, remaining after iron exploration on the Shakes iron deposit in the 1960s. provide most of the expo- I 4 sures of the pluton; however, it generatesa prominent high 100 P0 0 20 LO 60 80 100 on aeromagnetic maps (Map 92506; NTS Map 1C4G). %"Ar RELEASED The Latimer Lilke pluton is composed of black, granular, medium to fine-grained biotite magnetite clinopy- Figure 3-5. Biotite"Ad9Ar plateau date for the Ruggcd roxenite. Cumulate clinopyroxene and unaltered biotite Mountain pluton (analysesby P. Reynolds, 1993). display faint millimetre-scale layering in thin section. Bi- otite also forms an intercumulate phase with magnetite, gioclase laths, all setin a groundmassof potassium feldspar. which was the target of iron exploration (McIntyre, 1966). Hornblende and pyroxene occur as subhedral to euhedral Clinopyroxenite is locally brecciated and the space betweenprismatic grains and accountfor 2 to 10% of the rock. fragments is filled with potassium feldspar and coarse biotite. Part ofthe western flank of the pluton includesintru- POGUE AND BREWERY PLUTONS sive breccia, consisting of pyroxenite fragments supported The Pogue pluton, a poorly exposed body less than 3 in hornblende diorite. Porphyritic syenite around theperiph- square kilometresin area, crops outIO kilometres southwest ery ofthe body, noted by Souther (1972). was not seen dur- of the Limpoke pluton. It is composedof fine-grained, equi- ing our mapping. An unnamed satellitic ultramaficbody of granular hornblendeto biotite hornblende monzodiorite;bi- unknown extent lies 2 kilometres farther west. The third otite and hornblende comprise 20% of the rock. A body, theDanmation pluton, 1Okilometres totheeast, shares subtrachytic texture definedby flow-aligned plagioclase is most features of the Latimer Lake pluton but lacks syenite. developed at its eastern contact. The Brewery pluton con- It intrudes and hornfelses Stuhini Grouptuff. sists of pink hornblende quartz monzodiorite with about 25% mafic minerals. It is exposed only along an isolated EARLY JURASSIC TEXAS CREEK ridge 20 kilometres northeast of the Limpoke pluton, but PLUTONIC SUITE (189-195Ma) may extend to the east. The Early Jurassic Texas Creek plutonic suite includes calcalkaline plutons associated with economically impor- PERELESHIN AND OKSA CREEK PLUTONS tant precious and base metal vein deposits, like the Premier Potassium feldspar megacrystic quartz monzonite in- mine and Sulphurets depositsin the Stewart-Iskut area (Fig- trusions, the Pereleshin pluton and Oksa Creek stock, are ure 3-1; Anderson and Thorkelson,1990). The Texas Creek included in the Texas Creek suite because of their similar granodiorite, near Stewart, is an irregular-shaped pluton composition. The Pereleshin pluton underlies about 180 with comagmatic potassium feldspar megacrystic dikes andsquare kilometres, from Mount Pereleshinnonhwest across sills (“Premier porphyry”; Brown, 1987).The Limpoke plu- the Stikine River into the Coast Range; its extent is greater ton (Figure 3-6) is included in this suite on the basis of an Early Jurassic U-PI, zircon date (194*2 Ma; Brown er ol., 1992~;Appendix 13) and on the basis ofits composition and its associated copper and gold showings. A K-Ar hornblende date of I826 Ma (Appendix 12) for the Limpoke pluton may represent a cooling age.Two smaller bodies, the Pogue and Brewery plutons, are also includedin this suite. LIMPOKE PLUTON The Limpoke pluton, an elongate body approximately 8 kilometres long, underliesan area of21 square kilometres immediately southof Limpoke Creek. This two-phase, texturally heterogeneous stockis dominated by an outer phase of pale grey, mediumto fine-grained, equigranular biotite- hornblende quartz monzonite. The centre of the intrusion consists mainly of coarse to medium-grained plagioclase- megacrystic biotite hornblende monzodiorite with plagioclase phenocrysts, 1 to 2 centimetres in length, set in a fine-grained groundmass of potassium feldspar. The per- centage of mafic minerals increases toward the outer margins of the pluton, withthe colour index ranging from about 18 to 40. Hornblende is the dominant mafic mineral, but dark brown biotite locally coexists with dark green hornblende. Clinopyroxene occurs with hornblende and biotite in one locality. The intrusion contains magnetite as fine- grained granules, and they probably contribute to the significant anomaly apparent on aeromagnetic maps (Map NTS 104G). Apatite is a common accessory mineral. Leucocratic, potassium feldspar megacrystic syenite dikes intrude the eastern and western borders of the pluton and surrounding Upper Triassic sedimentary and volcanic rocks. The dikes are similar to syenite and alkali feldspar syenite dikes northwest of the Rugged Mountain pluton. They are characterizedby tabular, trachytic potassium feld- Figure 3-6. Distribution of Early Jurassic Texas Creek Plutonic spar phenocrysts 1 to 2 centimetres long, and smaller pia- Suite and Early Jurassic diorites.

62 Geological Survey Branch Minisfry ofEmplovmenf and Inveshnenl than that mapped by Brown and Gunning(1989b). It is commonly in complex agmatite wnes of diorite, granodiorite posed of grey, medium-grained, porphyritic hornblende and aplite. Locally, Cone Mountain granodiorite intrudes quartz monzoniteto granite. Potassium feldspar megacrysts along jointsof Early Jurassic diorite plutons. account for20 to 40% of the rockand anhedral quartz 10 to The Cone Mountain pluton, centredon Cone Mountain, 25%. Mafic minerals, euhedral black hornblende and trace underlies an area of 30 square kilometres and intrudes the biotite, comprise10 to 2070.Large titanite crystals, magnet- Stikine assemblage. Its eastern contact, theCone Mountain ite and apatite are accessory minerals. fault, is a mylonite zone 500 metres wide (cf: Chapter 4 A hornblende K-AI date of 2Mk7 Ma was obtained Structure and Metamorphism). from this body and is interpreted as the minimum age of A U-Pb zircon date of 184.7d.6 Ma (Brown era/., emplacement (Appendix 12). A Tertiary hornblende biotite 1992~;Appendix 13) for theCone Mountain plutonis inter- granodiorite, the Christina pluton, intrudes the Pereleshin preted to represent the age of emplacement of the suite. It body west of Mount Pereleshin. may be coeval with Hazelton Group volcanic rocks westof The Oksa Creekpluton, which is about3 kilometres in Yehiniko Lake (cf: U-Pb date for volcanic strata; Chapter diameter, is exposednear the headwatersof Oksa Creek. It 2). Discordant mineral pair and single mineral K-Ar dates is massive, coarseto medium-grained, crowded megacrystic for Cone Mountain suite plutons range from to Early Middle quartz monzonite containingpotassium feldspar megacrysts Jurassic. The Navo pluton yielded K-Ar dates of 182k7 Ma (up to60%). hornblende (up to 25%). and distinctive coarse- for hornblende and 163+6 Ma for biotite; the Dokdaonplu- grained titanite (up to2 cm long) and secondary epidote. ton yielded a hornblendeK-AI date of1586 Ma (Appendix 12). The hornblende datefor the Navo pluton is concordant EARLY JURASSIC(?) DIORITE with the Cone Mountain pluton U-Pb date;the other K-AI dates are considered tobe partially reset. INTRUSIONS The Strata Glacier, Dokdaon and DevilsElbow plutons The Geology Ridge and Davoplutons aretwo distinct, are the largest intrusionsof the Cone Mountain suite. They undated. bodies of diorite (Figure 3-6). The east-trending underlie an area of approximately 165 square kiiometres. Geology Ridgeplutonconsistsofconspicuous,blacktodark from the headwaters of Strata Creek west to DevilsElbow. grey, medium-grained, equigranular, biotite hornblende dio-They are unfoliated, medium-grained (biotite) hornblende ritetomonzodiorite.1twasdescribedasa"maficmigmatite" by Souther (1971). It is indeed texturally heterogeneous, with maiic pegmatites and hornblendites characterized by irregulardark patches ofcoarse-grained acicular hornblende up to 3 centimetres long and interstitial quartz, plagioclase cone Ut" suits and potassium feldspar. The northwest-trending Davo pluton ranges from quartz monzodiorite to hornblende diorite in composition and underlies an area of about 15 square kilometres. It intrudes Permian limestone and underlying strata.Its westem border, near the headwaters of Navo Creek, consists of a zone of vertical diorite schlieren, 50 metres wide, adjacent to recrystallized Permian limestone (cf Photo 4-14). Here hostrocks contain layersand podsof garnet andgarnet-diopside skarn up to 75 metres fromthe contact. No other plutons in the area have this strong, syn-emplacement (?) vertical fabric developed attheir margins.

LATE EARLY JURASSIC CONE MOUNTAIN INTRUSIONS(187-180 Ma) The Cone Mountain intrusions, a groupof eight grano- dioritic plutons, are spatially associated with and contain abundant angular xenoliths of the Early(?) Jurassic Geology Ridge and Davo diorites. They are the principal intrusions north of the Scud River and include the Cone Mountain, Navo, Dokdaon, Strata Glacier, Devils Elbow, Jacksons. Strata Mountainand Shebu plutons (Figure3-7). The Cone Mountainsuite(aninforma1nameusedherebecauseplutons of this age were previously unrecognized in the region) is characterized by leucocratic (colour indexIS) biotite hornblende granodiorite. Ubiquitous angular to rounded mafic xenoliths range from less than a metre totens of metres in Figure 3-7. Distribution of late Early Jurassic ConeMountain diameter (see Photo IC in Gunning, 1993a), and are com- plutonic suite.

Bullefin 95 63 granodiorite to quartz monzcdiorite which intrudes rocks YEHINIKO PLUTON of the Stuhini Group and Stikine assemblage. Titanite is a The Yehiniko pluton crops out over an area of about ubiquitous accessory mineral. 200 square kilometres.It is composedof distinctive fleshto The Jacksonspluton isan irregular bodyof granodiorite salmon-pink, medium-grained, equigranular biotite horn- which intrudes Carboniferous and Upper Triassic rocks 5 blende granite.It is distinguished from graniteof the Eocene kilometres south of the confluence of Stikine River and Strata Creek. It contains numerous pendants of metavol- Sawback pluton by its colour, higher mafic content(colour canic rocks adjacent to its contacts. Twokilometres west of index = 10-15) and presence of hornblende. Plagioclase is Strata Mountain, a broad V-shaped body of medium- moderately saussuritized, unlike in the younger Sawback grained biotite-hornblende quartz monzodiorite comprises pluton, where it is generally unaltered. Magnetite and sub- the Strata Mountain pluton.It intrudes rocks of the Stuhini ordinate titanite are ubiquitous. Along the Scud Glacier, the Group but contact relationships with Lower Jurassic vol- pluton intrudes pyroxene-phyric Stuhini volcanicrocks on canic rocks to the north are uncertain. The Shebou pluton, the eastand the Nightoutand Hickman plutons to the north 4 kilometres southeast of Strata Mountain, consists oftex- and south, respectively. The Yehinikopluton is interpreted turally heterogeneous hornblende diorite and subordinate to have been emplaced in the Middle Jurassic based on a leucodiorite. On the south sideof Strata Creek, this intrusion biotite K-Ar date of 1726 Ma, and biotite and whole-rock varies from fine to coarse grained, is locally foliated and rarely gneissic. On the steep slopes north of Strata Creek, Rb-Srdates of 17of16 Ma and 178+11 Ma (Holbek, 1988). the pluton is intensely altered and intruded by numerous pink, fineto medium-grained (biotite) hornblende graniteto NIKO PLUTON syenite dikes, thought to be comagmatic with the Middle The Niko pluton, west of the Scud Glacier, shares all Jurassic Saffron pluton: consequently, the contact relations the features of the Yehiuiko pluton and is included in the with Lower Jurassic rocksto the north are uncertain. Three Sisters suite.It yielded a biotite K-Ar dateof l77+7 Ma, which is concordant with dates fromthe Yehiniko plu- MIDDLE JURASSIC THREE SISTERS ton, and which is interpretedto represent the minimum age PLUTONIC SUITE (177-170 Ma) of emplacement (Appendix12). The Yehiniko, Niko and Saffron plutons are included in the Three Sisters suite, younger the phase of the Hotailuh SAFFRON PLUTON batholith (cf: Anderson, 1983a: Figure 3-8). West of Yehiniko Lake. distinctive pink, medium and locally fine-grained hornblende biotite granite to quartz monzonite underlies an area of about 30 square kilometres and comprises the Saffron pluton. Northwest of Saffron 7.. /I ,” “I. renit.) Creek, distinctiveorange to brown-weatheringoutcropsand regolith delineate the extentof this stock. Subordinate pale 2 Dokdoon grey quartz monzcdiorite, quartz monzoniteand hornblende diorite comprisethe southwest andsouthern partsof the pluton. The dioriteis intruded by granite and quartz monzonite apophyses of the Saffron pluton and is therefore slightly older. The intrusion is more heterogeneousin both composition and texture than the Yehiniko pluton. On the northeastmargin of the Saffron plutonthe steep contact with conglomerateof the Sustut Group is interpreted to be a fault. Contacts with Upper Triassic volcanic rocks and post-Late Triassic hornblende diorite onthe south,and with Lower Jurassic volcanicrocks on thewest, are intrusive andcountryrocksare strongly hornfelsed. Concordanthorn- blende and biotite K-Ar datesof 1626 Ma from the border phase monzonite and granite (Appendix 12). respectively, are interpretedto represent a minimum emplacement age for the Saffron pluton. CONOVER PLUTON West of the confluence of the Stikineand Chutine rivers, Stuhini Group rocks are intruded by distinctive senate to crowded plagioclase-porphyritic hornblende monzonite to monzodiorite bodies. The intrusions, including the Conover pluton (about 2 km2) and numerous associated sills, are texturally heterogeneous, but typically contain blocky to lath-shaped, locally trachytic plagioclase phe- Figure 3-8. Distribution of Middle Jurassic Three Sisters nocrysts, 3 to 5 millimetres long, in a groundmass of horn- Plutonic Suite. blende, potassium feldspar, plagioclase and quartz. The

64 Geological Survey Branch Conover intrusions have compositional, geochemical and Jurassic granites. and formsup to 50% of the rock. Potas- textural similarities to the Pereleshin pluton. However, sium feldspar ranges upto 30% and is locally megacrystic; hornblende yielded a 177sMa K-Ar date (Appendix 12), plagioclase averages 20% and biotite less than 4%. Horn- therefore, they are included with the Three Sisters suite. blende is absent, helpingto distinguish the Eocene plutons from the Middle Jurassic Yehiniko and Saffron plutons. MIDDLE JURASSIC DIKESWARMS AND DOK Limestone and rare argillite pendantswithin the granite STOCKS arealteredtoskarn,foliated,andatMountJonquette,exhibit Abundant and distinctive pink dikes of biotite-hom- "chocolate tablet" boundinage. Exoskam and less common blende-plagioclase (rarely potassium feldspar) porphyritic endoskam assemblages consist of gamet. diopsideand wol- (quartz) syenite, granite and (quartz) monzonite are exposedlastonite. Mafic dikes intrude the pendants, are deformed near the west and southwest contactsof the Saffron pluton. with the limestone, and are cut by the granite. Fine to me- They intrude Lower Jurassic and Upper Triassic rocks dium-grained diorite also intrudes the limestone pendants. within an irregular north-northeast to northeast-trending Gamet (almandine)-bearing aplite dikes, less than 1 metre zone markedby rusty, limonitic and clay-alteredrocks. This wide, crosscut bath the diorite pendants and the granite. suggests that the dikes,and in part, the alteration, are geneti- Along the Stikine River in Klootchman Canyon,the pluton cally related to the Saffron pluton and, together with the is strongly fractured. Farther north, near Missusjay Creek, prominent hornfels zone around it, suggest that it is epi- pendants of recrystallized limestone, several hundreds of zonal. Farther southwest along thetrend of this zone, on the metres across,clop out along the margin of the pluton, and ridge betweenDokdaon and Strata creeks, hornblende gran- fine-grained granite and aplite dikes extend the into country ite to quartz monzonite stocksand homblende-plagioclase- rock. Three kilometres southofMount Jonquette, the south- porphyritic (quartz) syenite and (quartz) monzonite dikes em margin of the pluton is marked by a heterogeneous, are also tentatively correlatedwith the Saffron pluton. The xenolith-rich zone over 100 metres wide, which contains stocks are associated with porphyry copper mineralization angular to roundedinclusions of folded phyllitic schistoseto on the Dok claims (Ulrich, 1971). metavolcanic(?) rocks and diorite (Photo3-4). The variation in degree of deformation of xenoliths suggests they were EOCENE HYDER PLUTONIC SUITE derived from different crustal levels or they had different (55-51 Ma) residence times within the magma chamber. The more de- The Cretaceous and early Tertiarywas a time of extensive syntectonic and post-tectonic plutonism and uplift in ru the Coast Plutonic Complex. In the Ketchikan area, the Coast Belt can be divided into three suites on the basis of age: western tonalite (55-57 Ma); central orthogneiss (ca. 127 Ma); and eastern granite(52-53 Ma; Arth efal., 1986). The eastern suite, equivalentto the Hyder Plutonic Suiteof Woodsworth el al. (1991). is the most extensive of the plutonic suites in the study area (Figure3-9). The plutons pas- sively intruded strata along the eastern edge of the Coast Belt at shallow crustal levels;they are coeval with volcanic racks of the Sloko Group, which are exposed in a discontinuous belt to the east. {CHRISTINA PLUTON The Christina pluton underlies an area of about 75 !square kilometres in the southwestern comer of the study area near Christina Creek. It is compositionally similar to :Middle Jurassic granodiorites, but yielded concordantK-Ar (dates of 56.1t2.0 Ma (hornblende) and 54.221.7 Ma (biotite; Appendix 12). A younger biotiteK-Ar dateof4S.122 ]\?a was reported by White et al. (1968). but is considered IObe partially reset. SAWBACK PLUTON The Sawback pluton, which underlies an area of 450 quare kilometres, is the largestpluton exposedin the west- central part of the map area.It consists of equigranular, dull grey to pink, biotite granite, characterizedby its medium to coarse grain size, well developed butwidely spaced joints (Photo 3-3) and relatively unaltered nature.Quartz is com- rnonly coarse grained, in contrast with that in the Middle Figure 3-9. Distribution of Eocene Hyder Plutonic Suite. Photo 3-3. Well jointed exposures, a characteristic of the Eocene Sawback granite pluton.in the Sawback Range, Coast Mountains,3 kilometres north of Cirque Mountain. formed blocks were either heated to higher temperatures, The Hamper pluton intrudes diorite and granodiorite allowingthem todeform ductily, orthey originatedat deeperplutons 5 kilometres southeast ofOksa Mountain Photo 3- crustal levels where higher stresses may have been preva- 5). This areaof multiphase intrusion and brecciation resem- lent. bles that described for the Sawback pluton southof Mount Jonquette, except no metamorphic xenoliths were identi- AmiddleEoceneK-Arbiotitedateof48.0cl.7Ma(Ap- fied. Inclusions vary from subrounded, ductily deformed pendix 12) is a minimum age for intrusion of the Sawback mafic schlieren to angular fragments of diorite. The xeno- pluton. Two small plugs southof Galore Creek includedin liths increase in size and abundance toward the contact of the suite, yielded K-Ar biotite dates of 48.9?4 and 53.5+4 the Davo diorite. Irregular patchesof hornblende-potassium Ma (Panteleyev, 1975, 1976). feldspar-quartz pegmatite with acicular hornblende occur in this area. At one locality, a granodiorite breccia xenolith is HAMPER PLUTON itself a block in the granite. The intrusiverelationships indicate that diorite and granodiorite were intruded prior to The Hamperpluton,about 35 square kilometresin area, the granite. A single granite xenolith observed within gra- is included in the Hyder suite. It intrudes the late Early Ju- nodiorite is an exception to this sequence. rassic Strata Glacier pluton and Oksa Creek pluton and is similar in composition (biotite granite) and texture to the Sawback pluton. Miarolitic cavities lined with quartz, epi- OKSA CREEK DIKESWARM dote and pyrite occurin the intrusion near Oksa Creek. Like A steeply dipping, north-striking bimodal dike swarm the Sawback pluton, itis also associated with skams. Near extends north for more than 35 kilometres from the head- the headwaters of Oksa Creek, theHamper pluton intrudes waters of Navo Creek to the confluence of Dokdaon and Permian limestone and a garnet (two phases), diopside, epi-Strata creeks.The swarm, up to 3 kilometres wide, is domi- dote and wollastonite skarn is developed forto upIO metres nated by prominent buff to white-weathering, quartz-phyric from the irregular contact. Boudinaged calcsilicate layers felsite and rhyolite dikes1 to IO metres wide. Some are flow and pods in grey marble contain quartz cores surroundedby banded and others are stainedwith manganese oxideon joint radiating wollastonite needlesand an outer rimof diopside. surfaces. The felsite dikes intrude Permian limestone and Malachite-stained fractures occur near the contact,in both crosscut a swarm of vesicular basalt dikes that trend nonh the limestone and intrusions. to northeast near the headwaters of Oksa Creek. The mafic

66 Geological Survey Branch Ministry of Employmenf and Invesfment

I dikes are narrower, np to 2 metres wide, closer spaced and ' more uniform in width. A biotite-rich felsite body exposed within the Oksadike j swarm at the head of Dokdaon Creek yielded a K-Ar biotite ' date of 49.7k1.7 Ma (Appendix 12). Therefore, the felsite dikes and coeval Sawback pluton may be intrusive equivalents of Sloko Group volcanic rocks.

TERTIARY(?) GRANODIORITE Limonitic weathering plagioclase-porphyritic grano- dioriteintheheadwatersoftheScudRiverfomsaelongate, north-trending body, covering an area of 7.5 square kilome- trees, subparallel to the Scud Glacier fault. The granodiorite intrudes Permian limestone, contains prominent white plagioclase laths in a fine-grained green groundmass, and is pervasively fractured and altered (chlorite, sericite, pyrite). The pluton is tentatively included in the Tertiary suite because of its porphyritic, high-level nature. Alternatively, it may correlate with a dated Early Jurassic pluton (Scud River pluton) exposed northeast of Galore Creek (cf: White et ai., 1968: Logan er ai., 1993a,b).

LATE MIOCENE (?) OR YOUNGER DIKES East-trending, metre-scale olivine(?) and pyroxene- porphyritic basalt dikes form twoswarms several kilometres wide, one within the Hickman pluton and the other nearthe contacts of the Yehiniko and Nightout plutons (Kuys dike swarm; Figure 4-2). The mafic dikes areprobably LateMio- cene or younger, and related to Mount Edziza Complex magmatism.

Fhoto 3-4. (a) Tightly folded, amphibolite-grade phyllite xenolithwithin the Geology Ridge diorite, along the migmatic northern contact zone with the Sawback pluton(DBR-90-18). Lithology and styleof dcformation of the xenalith suggesta probable Stikine assemblage protolith. (b) Brecciateddiorite xenolith andmultiphaseintrusion ofgranite IhesouthernconlactoftheSawhackpluton, along 3 kilometres south of Mount Jonquette and 500 metres north of (a) (DBR-90-19).Diorite blocks are angular to wispy, defining different degreesof deformation and foliationin both brittle and ductile regimes. British Columbia

observationsand petrographicexaminationsthat distinguish GEOCHEMISTRY AND TECTONIC plutonic suites. Voluminous calcalkaline, subalkaline plu- tonscomprise theTriassic Stikine suite (Hickman,Nightout, DISCRIMINATION OF INTRUSIVE Tahltan Lake, Little Tahltan Lake, Tahltan River plutons), ROCKS the Early Jurassic Texas Creek suite (Limpoke pluton), the Classification schemes for plutonic rocks attempt to late Early Jurassic Cone Mountain suite (Cone Mountain, achieve two goals: they distinguish rock types and help to Navo, Niko, Strata Glacier, Dokdaon plutons), the Middle interpret tectonic settings. Determinationof modal mineral Jurassic Three Sisters suite (Yehiniko, Saffron, Conover proportions of quartz, alkali feldspar, plagioclaseand feld- plutons) and the EoceneHyder suite (Sawback pluton). Two spathoids remains the preferred methodof subdividing plu- ultramafic suites display distinct chemistry relativeto each tonic rocks becauseof its simplicity andease of application other and to the calcalkaline suites; theyare Middle toLate (Le Bas and Streckeisen, 1991). Classification schemes Triassic Alaskan-type intrusions (Mount Hickman, Middle based solely on chemistry have inherent limitations becauseScud and Yehiniko ultramafites) along the flanks of the rock chemistry can be significantly modified by processes Hickman batholith, and Late Triassic to Early Jurassic ul- which include fractional crystallization, crustal contamina- tramafites (Rugged Mountain, Latimer Lake and Damna- tion, migration of volatile phases, crystallizationof minerals tion), associated with alkaline plutons. The following rich in trace or rareearth elements (e.g. monazite), and post- discussion summarizes the chemical characteristics of each crystallizatjon alteration(Pearceetul., 1984). Despite these plutonic suite in the project area and reviews their tectonic variations, general trends are recognized thatform the basis implications. for discrimination of igneous suites and corroborate field divisions. MIDDLE TO UTETRIASSIC Alkali-silica and AFM diagrams distinguish plutonic ALASKAN-TYPE ULTRAMAFIC PLUTONS rock suites and help subdivide the ultramafic cumulate bod- Samples from the Mount Hickman, Middle Scud and ies. Whole-rock samples that plot along the FeO-MgO tie Yehiniko ultramafites form a cluster on the alkali-silica dia- line on the AFM diagram are interpretedto reflect cumulate gram, and scatter along the FeO-MgO tie lineof the AFM mineral phases, not the bulk composition of the parent diagram (Figure 3-10a and b). Cumulate diopsidic py- magma. However, samples that plotoff the tie line may re- roxene, olivine and magnetite observed in thin section de- flect .magmatic compositions. These factors are important termine where samples plot. The positions of each sample when interpreting a suiteof samples distributed on the dia- on the AFM diagram reflect different cumulate mineralpro- grams. portions and mineral compositions; the Yehiniko and Mid- Whole-rock chemical analysesof 65 samples of intm- dle Scud bodies tend to have a restricted compositional sive rocks from the Stikine project area corroborate the range field and less magnetite comparedto Mount Hickman.

68 Geological Survey Branch .. .5 I A/CNK (f)

* :t;

VAG I .1 I 4 ' ' """' 10 ' ' 100 ' '"""1I000 Y t Nb '

-01 KZO Rb Ba Nb Zr Y Yb

Figure 3-10. Chemical characteristics of the Stikine suite compared with the Alaskan-type ultramafites: (a) Alkali-silica diagram.@) .4FM diagram. (c) Quam - alkali feldspar - plagioclase diagram of Slreckeisen (1976); Q=quartz, A=alkali feldspar, P=plagioclase, :I=granite,4=granodionte, ktonalite, kalkalifeldspar syenite,6'quanz alkali-feldspar syenite, 7=syenite, 7*=quanz syenite,&mon- ;mite, S*=qu& monzonite, 9=monzodiorite, 9*=quartz monzdiorite. IOdiorite, lO*=quam diorite. (d) Shand index values. (e) TectonicdiscriminationdiagramafterPearceeral.(1984);VAG=volcanic-arcgranites,ORG=ocean-ridgegranites,WPG=within-plate granites, synCOLG = syncollision granites. (0 Ocean-ridge granite (ORG) normalized geochemical patterns;ORG normalizingvalucs are listed in Table 3 of Pearce et a/.(1984).

- Bullelin 95 69 The MgOlMnO ratiosdistinguish the Middle to Late recognized, possibly because theyhave been altered (Neil1 Triassic Alaskan-typeand the Late Triassic to Early Jurassic and Russell, 1993; Figure 3-llc). Normative values were alkaline ultramafites; ratios greater than 90 are charac- determined with all iron assignedto Fez03; despite this, no teristic of the Mount Hickman, Middle Scudand Yehiniko normative silica was calculated. Neill and Russell (1993) plutons, whereas ratios lessthan 90 characterizethe Rugged documented that the phases are comagmatic and that the Mountain, Latimer Lake and Damnationintrusions. The ra- Rugged Mountain samples show an iron-depletion trend, tios are a functionof pyroxene compositions; Alaskan-type toward the potassium feldspar apex from hybrid to dike plutons have diopsidic pyroxeneand alkaline plutons con- phases (Figure 3-11). All the noncumulate samples are tain aegirine-augite (Neilland Russell, 1993). The Alaskan- metaluminous (Figure3-lld). type ultramafites differ from the alkaline suitein their lack Stuhini Group rocksin the area of the Rugged Mountain of syenite phases, pyroxene compositions and absence of pluton were not sampledin detail, however, shoshonitic la- garnet vas may occur in the area. For example, shoshoniticextru- sive equivalents of the alkaline plutons are recognized STIKINE SUITE around Galore Creek (Logan and Koyanagi, 1994) and in Some of the largest plutons in the project area belong the Nicola Groupof the southern Intermontane Belt(Mor- to the Stikine suite. They range in composition from mon- timer, 1987). zodiorite to granodiorite and tonalite with subalkaline, calcalkaline to tholeiitic affinities (Figure3-10a. b and c). The TEXAS CREEK SUITE Tahltan Lake and Little Tahltan Lake plutons plot in the tholeiitic field on an AFM diagram, presumably due to The Early JurassicTexas Creek suiteis represented by higher magnetiteand biotite contentsthan the other plutons a sample of quartz monzodioritefrom the Limpokepluton (Figure 3-lob). Stikinesuite samples displayI-type charac- and two samplesfrom the Pereleshin pluton (Figure 3-12a, teristics, a term defined by Chappell and White (1974) to b, c and d). They plot in overlapping fields with the Stikine signify pluton derivation from partial melting of igneous suite samples (Figures 3-10,3-15) and display I-type affin- protoliths, followedby normal igneous differentiation. The ity. Srikine suite has relatively high sodium (NazO >3.2% in felsic varieties),Shand‘s index lessthan 1.1 (metaluminous; CONE MOUNTAIN SUITE Shand, 1951; Figure 3-1Od), CIPW normative diopside or Late Early Jurassic Cone Mountain suite samples are normative corundum less than 1%. a wide compositional subalkaline. They havelower alkali contents at comparable spectrum, hornblende, biotite, accessory titanite and no silica values relative to samples of the Stikine and Three muscovite. Shand’s index reflects the degree of alumina Sisters suites (Figures 3-12a; 3-15). However, the three saturation; as alumina increases, the source crust is inter- suites overlapon theAFM diagram [Figure3-15(b)]. Sam- preted to be more evolved. Rock classificationof the Stikine ples collected from the Cone Mountain, Navo, Dokdaon and suite using normative chemistry on the QAP ternary dia- Strata Glacier plutons were identifiedas granodiorite in the gram (Figure 3-1Oc) agrees closely with modal classifica- fieldbutrangefromtonalitetograniteonFigure3-12c.They tion of stained slabs performedin the field (compare “rock display I-type affinities with metaluminous to mildly per- code” with “QAP” in Appendix1 I). aluminous character (Figure3-12d).

LATE TRIASSIC TO EARLY JURASSIC THREE SISTERSSUITE ALKALINE & ULTRAMAFIC PLUTONS Plutons of the Middle Jurassic Three Sisters suite are The Rugged.Mountain suite variesin composition from subalkaline, calcalkaline, I-type granites, except for one syenite clinopyroxenite and has clear alkaline charac- to dike sample that fallsin the alkaline field (Figure3-13a, b teristics, in contrastto other plutonsin the study area (Figure and c). The intrusionsare dominantly peraluminous(Figure 3-lla). Monzonite dike, syenite andhybrid (mafic syenite) 3-13c), with normativecorundum greaterthanI %. Samples samples fall alonga line on the AFM diagram that can be from two phases of the Saffron pluton are represented: the extended from the distinct clusterof clinopyroxenites to the main granite and the border quartz monwdiorite. Theyare alkali-rich dikes (Figure 3-llb). The pattern illustrates an widely separatedon theplots. A monzodiorite fromthe alkali-enrichment trend, which is compatible with extrac- Saf- fron pluton, a monzonite from the Conover pluton, and a tion of cumulate aegerine-augite from an assumed parent granodiorite dikeplot in the metaluminous field (Figure 3- melt (clinopyroxenite cluster).Evolution to more potassium 13d). rich residual melts ultimately produced the potassium-feldspar megacrystic dikes. Cumulate aegerine-augite, magnetite and melanite garnet in the ultramafite samples (NeillHYDER and SUITE Russell, 1993) determine where samples ploton the AFM Chemical characteristicsof the Eocene Hyder suite plu- diagram (Figure 3-llb). In the study area, these phasesare tons are similar to those of the Three Sisters suite;they are unique to the alkaline suite and explain the distinct distribu-dominated by subalkaline, calcalkaline graniteof I-type af- tion on the AFM diagram relative to the Alaskan-type ul- finity (Figure 3-14a, b and c). They range in composition tramafites discussed previously. Although the syenitesare from tonalite to granite (Figure 3°C). The intrusions are nepheline normative and plot in the foid-bearing syenite peraluminous and metaluminous (Figure3-14d), with nor- field, no modalnepheline or other feldspathoids havebeen mative corundum greaterthan 1%.

70 Geological Survey Branch Ministry of Employment and Investment

(:a) 16

Latimer Lake

Na20+K,0 MgO

2 Y 2 \ a

1 too0 :

ayrrC0LC

WPC

1 Rb VAG 10 ORC

I I , I , ,,/,I , , , ,,,,,I I 10 100 1000 Y + Nb

Figure 3-11. Chemical characteristics of the Rugged Mountain complex: (a) Alkali-silica diagram. (b) AFM diagram wih mineral compositions obtained from microprobe studies by Neill (1992). Gunning (1993a). and Deer et al. (1977). Comparison of Rugged Mountain intrusions and Averill Plutonic Complex (from Neill. 1992). Solid squares = Rugged Mountain intrusions, open squares = Averill Complex. (c) Quartz - alkali feldspar -plagioclase diagram; 7' = foid-bearing syenile, 8' = foid-bearing monzonite. (d) Shand index values.(e) Tectonic discrimination diagram after Pearceet 01. (1984); abbreviations as in Figure 3-10(e).

- Bulletin 95 71 FeO

L Early Jurassic

A Lale Early Jurassic

GeologyRidge Diorile

Limpcke +cons Ut". NOVO cons Ut". Alkaline Dokdoon 4 SubaUcaline / GeologyRidge Diorite 04 35 I 35 45 55 65 75 '1 SiO, Q

looo WCOLC I

100

ORC Rb e VAC

.01 ' I K20 Rb Ea Nb Zr Y Yb

Figure 3-12. Chemical characteristicsofthe Early Jurassic Texas Creek and late Early Jurassic Cone Mountain suites: (a) Alkali-silica diagram. @) AFM diagram. (c) Quam - alkali feldspar- plagioclase diagram with fields and abbreviations as shownin Figure 3-IWc). (d) Shand index values. (e) Tectonic discrimination diagram after Pearcc et ol. (1984). (0 Ocean-ridge granite (ORG)normalized geochemical patterns; ORG normalizing values are listedin Table 3 of Pearceel nl. (I 984).

72 Geologicol Survey Branch Minisrry ofEmploymenr and lnveshnenr

.o I I ' K,O Rb Ba Nb Zr Y Yb

Figure 3-13. Chemical characteristicsof the Middle Jurassic Three Sisterssuite: (a) Alkali-silica diagram.(b) AFM diagram. (c) Quartz - alkali feldspar - plagioclase diagram with fields and abbreviations as shown in Figure 3-I0(c). (d) Shand index values. (e) Tectonic discrimination diagram after Pearce er a/. (1984). (0 Ocean-ridge granite (ORG)normalized geochemical patterns; ORG normalizing values are listed in Table3 of Pearce ef a/. (1984).

Bullerin 95 73 I K20 Rb Ea Nb Zr Y Yb

Fiyre 3-14. Chemical characteristicsof the Eocene Hyder suite: (a) Alkali-silica diagram. AFM(b) diagram. (c) Quartz - alkali feldspar - plagioclase diagram with fields and abbreviations as shown in Figure 3-10(c). (d) Shand index vaules. (e) Tectonic discrimination diagram after Pearceet al. (1984). (0 Ocean-ridge granite(ORG) normalized geochemical patterns;ORG normalizing values are listed in Table 3 of Pearce et al. (1984).

74 Geological Survey Branch FeO

.* 0 _.., ., , , , , , , , 35 45 55 83 73 83 SiO, Q

5 P .4 .5 I 2500 r A/CNK

'ooo~Rb100 . .i...... WPC

10 V" c .. . .

1 10 100 1000 Y + Nb R1 = (4Si-II(Na+K)-Z(Fe+Ti)

Figure 3-15. (a) Total alkali-silica variation diagram displaying the distinctly alkaline characterof the Rugged Mountain pluton compared to all the other suites (alkaline- subalkaline division after Imine and Baragar,1971). The Yehiniko and Sawback plutonsare clearly the most silicic. Mafic border phasesof the plutons have not been included in this plot. Mineral compositionsare from microprobe studies b'y Neil1 (1592). Gunning (1993a). and Deer et al. (1977). @) AFM diagram (calcalkaline-tholeiitic division after Irvine and Baragar, 1971) for plutonicrocks from the project area; notethat ultramafic rocks plot within the tholeiitic field. Eocene Hyder suite samplesare from the Sawback pluton, except onefrom Christina pluton. (c)Quartz - alkali feldspar- plagioclase - feldspathoid diagram for plutonic nxks using the classification schemeof Streckeisen (1976), based onmodal mineralogy for rocks withless than W% mafic minerals. (d) Shand's index diagram showing relative alumina saturation (Shand, 1951); most plutons are metaluminous, only the granites are peraluminous. A/NK = AIzOd(Na20 + KzO), NCNK = AIzOd(Ca0 + NazO + Kz0). (e) Tectonic discrimination diagram for plutonic n~ks;(Y+Nb)versusRb(afterPearceeroL,1984).(f)GranitoidsamplesplottedontheRl-R2multicationicdiagramwilhsuperimposed kctonic environment boundaries (Batchelor and Bowden,1985). TECTONIC DISCRIMINATION Samples fromthe Rugged Mountainpluton straddle the Since Chappell and White (1974) first proposedthe I field boundary between the volcanic arc and syncollisional and S-type subdivision, I-type granites have been further granite fields of Pearce el nl. (1984; Figure 3-11(e)). The subdivided intoM and A-type granites with respective deri- alkaline chemistryand mineralogy is unique among the plu- vation from oceanic and continental crust (Pitcher, 1982). tonic suites but the tectonic setting is ambiguous. Empirical and theoretical studies combinedwith higher pre- EARLY JURASSIC cision analytical datacontinue to refine chemical classification schemes and discrimination of granitoid tectonic The monzodioritesample forthe Limpoke pluton falls regimes, most notably forA-type granites (cf:Whalen et nl., within the volcanic-arc granite field on the (Nb+Y) versus 1987; Eby, 1992). As wel1,rareearthelement (REE)patterns Rb plot of Pearce ef al. (1984; Figure 3-12e). This is com- can be employed to discriminate among tectonic settings patible with the interpreted arc setting for Hazelton volcan- (eg. Pearce et al., 1984). Ocean ridge granite (ORG) nor- ism farther south in the Iskut-Stewart area (e.& Anderson, malized geochemical patterns for the subalkaline Triassic, 1993). Early and Middle Jurassicand Eocene plutons all display a MIDDLE JURASSIC similar patternof strong enrichmentsin large-ion lithophile elements (Sr, K, Rb and Ba) and depleted Nb, Zr, Ti, Y and Analyses from most Middle Jurassic Three Sisters suite Yb relative to the norm (Figure 3-10(9to 14(f)); such fea- plutons plot in the corner of the volcanic-arc granitoid field, close to the syncollisionalfield (Figure 3-13e). They mark tures are typical of volcanic arc granitoids (Pearce et a!., 1984). Extrusive rocksof the Stuhini Groupmimic plutonic the first episodeof evolved granitic plutonism in the study chemistry, with REE patterns typicalof subduction-gener- area and presumably signify a maturing (thickening)of the crust. Their extrusiveequivalents may be the less extensive, ated calcalkaline arcs (Pearce, 1983;cf: Chapter 2). Meso- zoic plutons of Stikinia have chemical characteristics younger part of the Hazelton Group. similar to those of Pacific and Andean-type magmas EOCENE (Pitcher, 1982). Our geochemical data suggest that the Stikine Terrane crustevolved from a primitiveisland arcin The voluminous Eocene Sawback plutonof the Hyder the Late Triassic to a mature continentalarc by the Middle suite displays volcanic-arc granitoid chemical charac- Jurassic. This corroborates tectonic models proposed for teristics much like the Middle Jurassic Three Sisters suite northern Stikinia. The general enrichmentin silica and al- (Figure 3-14e). Theextensive plutonism is attributed to sub- kalis from Triassic through to Middle Jurassic and Eocene duction of Pacific oceanic plates beneath theNorth Ameri- is illustrated in Figure3-15(a); the same feature is reflected can plate. by the progression from metaluminous to peraluminous TEMPORAL EVOLUTION OF PLUTONS: THE compositions. Trace element data for the subalkaline plu- OROGENIC CYCLE tons show similar trends from primitive to more evolved volcanic-arc signatures through time (Figure 3-15(f)). The In general, atemporal progression from metaluminous, following discussion considers four plutonic periods and low-silica quartz diorite to granodiorite plutons in the Tri- their tectonic implications: Late Triassic, Early Jurassic, assic to more evolved peraluminous granite plutons by the Middle Jurassic and Eocene. Middle Jurassic and Eocene is evident (Figure 3-15). Batchelor and Bowden (1985) modelled the progression of LATE TRIASSIC compositions through an orogenic cycle on amulticationic Stuhini Group intravolcanic conglomerate contains diagram (Figure 3-15(f)). The majority of calcalkaline in- granitoid clasts that are indistinquishable from Hickman trusions fallwithin the pre-plate collision (destructive plate pluton granodiorite. Conglomerate occurs predominantly margin) field, except forMiddle Jurassic and Eocene gran- along the western flank of the pluton. Anderson (1983a). ites that liein the late-orogenic field. Thediagramillustrates documents similar polymictic conglomerate within the that Triassic, pre-plate collision granitoidsevolved compo- Stuhini Group adjacent tothe Hotailuh batholith. The sub- sitionally toward Middle Jurassic granite, as predicted for rounded clasts provide evidenceof rapid unroofing of Tri- typical orogenic cycles (cf:Batchelor and Bowden, 1985). assic plutons duringLate Triassic volcanism.

76 Geological Survey Branch CHAPTER 4 STRUCTURE AND METAMORPHISM

lFigure4-1.DistributionofmajorfaultsinnonhwestemBritishColumbia,modifiedafterBradfordandBrown,1993a;Evenchick,1991b.c; Ikwis, 1992; Logan era/., 1992b; Mihalynuk er al., 1994; Read. 1983, 1984; Souther, 1959, 1971, 1972;and Wheeler and McFeely, '1991.CLF = Chutine Lake fault, CMF = Cone Mountain fault, FKF = Forrest Ken fault, LLF Long lake fault, MA = McTagg anticlinorium, MCG= Mess Creek graben.MF = Mwsehom fault, MP= Mwsehorn pluton. NLG= Newmont Lake graben,OB = Ophir 13reak, SF = Sulphurets fault, SGF= Scud Glacier fault, SU/HF= South Unuk/Harreymcl fault, THS-LFZ = Tally Ho shear-LleweUyn fault wne. URF = Unuk River fault, WLF= West Lake fault, WSF= West Slope fault.

tiullerin 95 77 King Salmon fault system comprises west to northwest- ble 4-1): pre-Late Triassic contraction (Dl), and structural trending, southwest-verging folds and faultswhich involve culmination development (Dz); post-Late Triassic to pre- rocks as young as the LowerJurassic Laberge Group, that Toarcian contraction (D3); and Middle Jurassic to Creta- developed during Middle Jurassic contractional deforma- ceous contraction (D4). The earliest episode was tion morstad and Gabrielse, 1986). This is interpreted to synmetamorphic and produced widespread chlorite-sericite mark the final accretion and obduction of Cache Creek Ter-foliation (SI)and rare isoclinal folds(FI) in Carboniferous rane onto Stikinia. The Skeena fold belt comprises north- rocks. SI was folded during D2 into open to tight chevron east-verging folds and faults that developedin the Bowser folds (F2). Evidence for the timingof Dz remains equivocal. Lake and lower Sustutgroups in latest Jurassicto Early Cre- Open folds, overturned beddingand reverse faults, possibly taceous and latest Cretaceous to early Tertiary time, during northeast-verging, developed during D3, and the younger accretion of the Intermontane Superterrane to ancestral age limit anis angular unconformityat the base theof Lower North America (Evenchick, 1991b, c). The Sumdum-Fan- Jurassic HazeltonGroup. D4 produced crenulationsin phyl- shaw deformation occurredin mid-Cretaceous to Paleocene litic Carboniferous strata and tight folds in Permian lime- timeandmayrepresenttheundenhrustingofAlexanderTer- stone and mylonitic foliationsin a late Early Jurassicpluton. rane beneath Yukon-Tananaand Taku terranes (McClelland A notable feature in the project area is the contrast in etal., 1991). Brittle deformation postdatingthe Skeena fold structural trends of Paleozoic and Triassic strata. North of belt is characterizedby north-trending transcurrent and ex- the Stikine River, folds and faults trend northeast and east, tensional faults, which formed in Miocene and later time but to the south, they trend north and northwest 4-2). (Figure (Souther, 1970). following a change from pure convergenceThe orientation of Permian limestone massifs delineates to oblique convergence of Pacific plates relative to the thesewest- trends most clearly. This change in orientationis also em ancestral North America margin (Engerbretson et ai., illustrated in Carboniferous strata between Devils Elbow 1985). and Missusjay Creek; however, the closure itself is under In this chapter we describe structures related to four the Stikine valley alluvial fill.West of the map area, a similar episodes of deformation, review several fault systems and flexure from west to northwest-trends beenhas documented conclude with a brief discussionof metamorphism. The goal by Souther (1959). These changes are probably due to a is to document numerous structural elementsthat may ulti- combination of folding and faulting. However, delineating mately be used to develop a more detailed structural evolu- exact contact relationships remains elusivedue to poor ex- tion for the region.Our challenge was to group diverse and posures in critical areas. disparate features and determine age constraints.The timing of many structural featuresis poorly constraineddue tolack PRE-LATE TRIASSIC DEFORMATION of marker horizons, and because different fold styles de- @I velop where competency contrast between lithologic units and Dz) is high. In addition, the paucityof Jurassic or younger strata Four southwest-widening structural culminations (Lit- in most areas prevents unequivocal assignmentof many fea- tle Tahltan Lake, BarringtonRiver, Chutine River and Mis- tures to specific deformational episodes. susjay Creek culminations), and one trending south Four episodes of deformation in the studyarea are (Ta- southeast nearthe Scud River,are underlain by variably foliated and folded Permian and older rocks 4-2).(Figure They

TABLE 4-1 SUMMARY OF STRUCTURALFEATURES IN THE PROJECT AREA

T iming Fold style Planar Linear structureLinearPlanarMetamorphicstyle TimingFold Area Orientation of StNCture minerals fold planes fold minerals StNCture pre-Xate ~soclinal Axial planar VariableChlorite, due Little Tahltan Lake, Triassic (none later sericite toF,axes fold Barrington River, observed foliation 61) (none recogized foldingChutine River,Scud in map area) Lake Butterfly River,in map area)

post-Tight,chevron, Spaced axial Rare Lake,TahltanConsistentLittle Middlesimilar folds + planarcleavage F2 axes, BarringtonRiver,within T riassic structural domains Chutine River Chutine domains structural Triassic (S2) pre-Late culminationspre-Late so3 Triassic? lineations

post-Norian ~. FaultedMountainopen Crocusnone Northwesf None none pre-Toarcianfolds

MiddleSW-vergent + planarAxialChevron fold None Northwest to MountainCone axes north Jurassicto upright, cleavage axes Cretaceouschevron

78 Geological Survey Branch Permian Itmestone Paleozoic Structural culminations 1. Little TahltanLake 2. Barrington River 3. Chutine River 4 MissuS)ay Creek

x-x rnylonite zones Trlasstc-Jurassic uncontorrnitv

Figure 4-2. Major structural elements in the project area. AF = Ambition fault, BoF = Boomerang fault, BuF = Butterfly fault. CaM = Castor mylonile, CMF= Cone Mountain fault, KFZ = Kitchener fault zone, KDS = Kuys dike swarm, MSC= Middle Scud Creek faults, NSZ = Navo shear mne. OCDS = Oksa Creek dike swarm. SGF = Scud Glacier fault, X = pendant of folded metavolcanic rocks.Y = pendant of folded schist within Geology Ridge diorite, and YF= Yehiniko fault.

Bullerin 95 79 Photo 4-1. Characteristic deformation in Stikine assemblage phylliticturf in the Tahltan Lake structural culmination:(a) Nonhwest-verging, tight, angularpolyharmonic foldsofgreen and grcy phyllitc with axial planarclcavagc; (b) Ccntimetre-scale, north-verging, rounded to chcvron-style folds. The chlorite-sericitc foliation (SL)is coplanar to bcdding(So) and both are foldcd, therefore, at least two phases of deformation are evident. Deformed quam vein is shown by thc “x”. !record at least twophases of pre-Late Triassic deformation LITTLE TAFILTAN LAKE CULMINATION .and contrast sharplywith surrounding more massive Meso- The LittleTahltan Lake culmination is characterizedby :zoic strata. The northern two culminations expose poorly tight chevron folds(F2) and strata with a penetrative chlo- dated, tightly folded@2), penetratively foliated@I) rocks, rite-sericite foliation (SI)developed in greenschist-grade (correlated with dated Carboniferous or older units to the metavolcanic rocks and rare limestone. Northwestof Little .north (Bradford and Brown, 1993b) and south (Holbek, Tahltan Lake, thinly layered, green and maroon phyllitic 1988; Logan and Drobe, 1993b) on the basis of lithology. rocks are intensely folded into moderately steeply to south- .metamorphic grade and fabric. The lack of penetrative fab- east-inclined folds with subhorizontal, northeast-trending rics in surrounding massive Mesozoic strata, and more in- fold axes (F2; Photo 4-1). The centimetre to metre-scale, :tense and tighter folding and metamorphism of Paleozoic open to tight chevron folds verge northwest. Locally, this :strata within the culminations areused to conclude that these second phase of folding has generated spaced axialplanar ;are structural culminations. cleavage and crenulated SI foliations. No new mineral growth is evident on the axial planar surfaces of F2 folds. PHYLLOSILICATE FOLIATION(Dl) White quartz veins and pods, presumably synmetamorphic Penetrative phyllosilicate foliations, variably devel- (Dl), are deformed, which suggests thatD2 &formation oc- (oped in pre-Triassic strata of the culminations. are inter- cumd after thepeak of metamorphism (Photo 1).4- Locally, preted to be products of the oldest deformation and mullions parallel the SwS1 intersections and macroscopic metamorphic episode(Dl). The chloriteand scricite mineral fold axes and are developed where competency contrast is ;growth suggests that deformation was synchronous with great, such as in interlayered limytuff and siliceous tuff. ;greenschist-grade metamorphism. Synmetamorphicquartz Tightly folded phylliteand limestone of the Stikineas- $reins formedat this timeand were deformedby later folding semblage contrast with massive limestone and unfoliated ~n;see Photo 3a in Gunning, 1993a). Rare, rootless isocli- tuffaceous sedimentary mks of the Stuhini Group across nal folds are products of this earliest phaseof deformation, the faulted southeastcontact of the Little Tahltan Lake cul- they are more commonin correlative strata to the northwest mination. The northern contact was not mapped. (Bradford and Brown. 1993a). The foliation observedin Carboniferousstrata may cor- BARRINGTON RNER CULMINATION relate with a pre-Permian deformation. Ken (1948a) de- In contrast to the LittleTahltan Lake culmination, few !;cribcdasubtie structural discordance betweenpre-Permian macroscopic tight folds were observed in the Barrington and Permian strata and a chert-bearing conglomerateat the River culmination. Rocks within it display a peneeative, base of the Permian limestoneat Missussjay Mountain. Far- moderate to steep southto southeast-dipping phyllitic fabric ther southin the Sphaler Creek and Forrest Kerr map areas, (SI) that intersects bedding (So) at low angles, suggesting Logan and Koyanagi (1994)and Logan, Drobe and McClel- that tight folds are present, althoughclosures are rare. Bed- land (in preparation) provide evidence of pre-Permian de- ding-cleavage intersections suggest that there majoris a an- formation where isoclinal folds of mid-Carboniferous tiformal closure that plunges gently to the east in the limestone are overlain by Late Carboniferous to Permian Banington River valley, with secondary closures on the polymictic volcanic conglomerate containing mid-Carbon- northern limb. As in the Little Tahltan Lake culmination, iferous limestone clasts. quartz tension veins are common but appear less deformed. Local kinked @2) phyllosilicate foliation has a moderate DEVELOPMENT OF STRUCTURAL south-dipping axial plane and plunges gently east or west CULMINATIONS (02) Strong ductile to brittle deformationof Carbniferous tuff light to close D2 chevron-style folding of composi- in the culmination (Photo 4-2) contrasts with massive tional layering and SI,and the developmentof culminations Stuhini tuff exposed to the east. Contacts between constitu- me interpreted to te pre-Late Triassic. Late Triassic and ent lithologies were not observed. younger rocks do not exhibit tight folding adjacent to the northern culminations, and in general, bedding attitudesin CHUTINE RIVER CULMINATION IJpper Triassic strata do not conform tothe margins of the Permian limestone delineates the east-trending Chutine culminations. Locally, such as at Missusjay Creek, Upper Riverculmination.Thethicknessoflimestonechangesfrom Triassic rocks appearto lie unconformably on foliated Car- less than 200 metres near Wimpson Creek to over 2800 bniferous strata. Folded northeast-trending Permian lime- metres east of Tuffa Lake, probably due to Dz folding and stone lieswithin a massive Late Triassicpluton (Moosehorn faulting. A northward-inclined open fold on the northwest pluton, Figure4- I), immediately northwestof the studyarea limb of the culmination, theUgly anticline, hasan amplitude (Bradford and Brown, 1993a, b). However, the data are of more than 150 metres and is outlined by Early Permian somewhat equivocal and competency contrast duringpst- limestone with a core of variably foliated,rusty weathering, Triassic deformation may account for the differences in siliceous siltstone, tuff and minor, discontinuous, structural stylebetween pre- and Late Triassic units.For the recrystallized limestone (Photo 4-3). Lapilli tuff contains a mnainder of this discussion it is assumed that these culmi- pervasive phyllitic foliation but pillow basaltis massive to nations formedbefore the Late Triassic. If they are younger, faintly foliated, illustrating that strainis partially controlled they may represent the deeper crustal level, northwestern by lithology. Fast-trending beds and foliation planes dip extension of the Skeena fold belt. steeply to the south or north.

- Bulletin 95 81 West of the Ugly anticline and south of the Chutine bedding. However,at this locality there is no gouge or shear- River, Permian limestone is complexly folded into open ing to suggest significant faulting. Elsewhere within the folds with rounded closures, andtight chevron folds. Chev- Kitchener faultzone. both units are folded and faulted. Far- ron-folded Middle Triassic black mudstoneand chert crop ther east, near Tuffa Lake, the chert unit is absent,probably out immediately north of thePermian limestone and within due to faulting, and Stuhini Group tuffaceous wackestruc- the Kitchener fault zone (Photo 4-4). Locally, folds are turally overlies Lower Permian limestone (unit IPSc). disharmonic with thickened hinge zones and thinned limbs, Northwest of Tuffa Lake, Middle Triassic chertand Stuhini and some arerootless. Faint sericite-chloritephyllitic folia- Group tuffaceous wacke are structurally interleaved within tion parallel to bedding is common. North of Ugly Creek the Kitchener fault zone. On the northeast wall of the Bar- and the Kitchener faultzone Upper Triassic strata are gentlyrington River canyon, upstream from the placer operation, dipping. competent middle Triassic chertis folded into chevrons di- Farther eastwithin the Chutine River culmination,east rectly above folded Permian limestone. of the Barrington placermining camp, foldsin the limestone are tight to isoclinal and are associatedwith bedding-parallel AGE CONSTRAINTS AND TAHLTANIAN faults. Small-scale fault duplex structuresare common. An OROGENY east-trending, upright isoclinal fold contrastswith a recum- Folding of Paleozoic strata in these culminations oc- bent fold of darker weathering, well bedded limestone ex- curred before theLate Triassic andEarly Jurassic. Massive posed on a cliff face north of Jimjack Lake and illustrates augite-phyric basalt dikes, interpreted to be feeders to the complexity of the deformation. Stuhini Group volcanic rocks, intrudefolded, phyllitic rocks The contactbetween Permian and Triassicrocks which in the Bamngton River culmination. In the Chutine River outlines the culmination iswell exposed immediately north culmination. folded Paleozoic rocks are cut by massive fel- of the Ugly anticline, where Lower Permian limestone bedssic dikes related to the Early Jurassic Limpokepluton. Far- dip steeplynorth and areoverlain paraconformably by buff- ther south, near the Scud River, angular blocks of tightly weathering Middle Triassic chertbeds (unit mTc). This area folded (D2 folds) mafic schist occurwithin massive Geology lies within the southern limit of the Kitchener fault zone, Ridge diorite, correlatedwith the Early Jurassic dioritesuite where numerous faults are subparallel to steeply dipping (Photo 4-5; locality Y on Figure 4-2). Assuming the schist

Photo 4-2. Characteristic microfabricsof rocks in the Barrington River culmination: (a) Chlorite-sericite-rich ashtuff interlayered with recrystallized limestone (INE91-360);@) Well foliated crystal tuff with prominent presssure shadows between plagioclase crystals (13191-182). Photo 4-3. View northwest to the Ugly anticline, an inclined, open fold of rusty weathering siltstone (uCSS) and well bedded Lower Permian limestone (IPSc) which are overlain unconfomably by Middle Triassic chert (mTc;see Figure 2-8). The nature of the contactis quivocal; beds are parallel across the contact and the chert appears rest to paraconfomably on the limestone. Alternatively, there may be a bedding-parallel fault betweenthe two units.

Fhoto 4-4. Chevron folded Middle Triassic cherton northcm edge of the Chutine River culmination, illustratingthe marked competency contrast between the chert and calcareous layers. Chert deformsby brittle failure andcaIc~rcous layers flow into the fold closures.

83 Photo 4-5. Tight folds with subangular clasurcs developed in mafic schist that occurs in angular pendants within massive Early Juras- sic Geology Ridge diorite (note:pluton is outside fieldof vicw; DBR90-18). is correlative with the Stikineassemblage, this providesan- (Figure 4-3; Photo 2- 15). Norian beds are locally overturned other pre-Early Jurassic age constraint. to the nonheast immediately below the angular unconfor- It is suggested that the culminations formed duringthe mity. Elsewhere, more massive and competent Stuhini Tahltanianorogeny, aPermo-Triassicepisode ofuplift,fold- Group volcanic strata underlie the well bedded clastic rocks ing, regional metamorphism and plutonism recognized in and have steeper beddingattitudes than the Hazelton strata. the Tulsequah and Telegraph Creek areas (Souther, 1971). The angular unconformity is a sharp contact with no This interval corresponds to Earlyan to Middle Triassicde- evidence of faulting; the surface is essentially flat, and a positional hiatus noted throughout much of Stikinia basal conglomerate or regolith is notably absent along this (Souther, 197 I; Read and Okulitch,1977). Coeval events to ridge (Photo 4-6). A basal polymictic conglomerate is ex- the northeast and south are the Cassiar orogeny (White, posed to the north. The unconfomity surface displayssig- 1959) and Sonoman orogeny of the southwestern United nificant relief farther north-northwest in Helveker Creek(cf: States (Wyld, 1991). Read (1983, 1984) and Read el al. Chapter 2; Photo 2-14),East of Mount Kirk, it is marked by (1983) suggest a slightly older, Late Permian to Early Tri- a basal Hazelton Group volcanic conglomerate lying on assic age for this event. massive Stuhini flows. Elsewhere in the study area, bedding attitudes of the POST-NORIAN AND PRE-TOARCIAN Stuhini Group vary greatly. Folds are rare and recognized CONTRACTION OF STUHINI GROUP only in thinly bedded sequences: axial planar cleavages are (D3) absent, in contrast with Paleozoic rocks. More massive vol- A spectacular exposure ofan angular unconformity es- canic rocks and local limestone horizons are unfolded and tablishes an importantdeformational event that has not been lack penetrative foliations, except north of the Scud River much discussed in the literature. It correlates with a regional where mafic crystal tuff displays a chlorite foliation (Gun- angular unconformity east of Schaft Creek (cf: Logan and ning, 1993a). An isolated recumbent fold of tuffaceous Drobe. 1993b). near Unuk River fault (Henderson el a/., wacke within massive volcanic rocks is exposed on a cliff 1992; Lewis et al., 1993) and at Oweegee Dome (Figure face north of Rugged Mountain. Upright, northwest-trend- 4-2) as documented by Greig and Gehrels (1992). ing open folds with subhorizontal axes are developed in Steeply dipping, folded and faulted Norian Stuhini thinly bedded siltstoneand Carnian limestone near the west Group clastic rocks are unconformably overlain by gently shore of Tahltan Lake. These folds may be correlativewith to moderately dipping Toarcian Hazelton Group volcanic the northeast-directed contractional event defined between rocks along the ridge between Strata and Quattrin creeks Strata and Quattrin creeks. 254' 074' Hazelton Group - Metres % angular calcalkaline Toarcian unconformity tuff-breccia and flows 'z r Iu 2000 Feet 1 0 (Zlrcon U-Pb 185+7-2 Ma) U I 6000 4 -n Norian

[LateNorian '. 1000 -__ SedimentaryRocks) " " ." """

Stuhlnl Group """"" 2oao-k*.* + + * ' + volcanlc+Glacier rocks

i,,ometrez l+*..+*\ 0

Figure 4-3. Schematic cross-scction illustratingdcforrncd uppcr Norian clasticrocks of the Stuhini Group unconfomably overlain by Toarcian flows and tuifs, bctwcen Strata and Quattrin crecks.

Photo 4-6. Svuctural discordance between thinly bedded Norian sedimentaryrocks and overlying Lower Jurassic volcanic rocks.This ,close-up ofthe contact that is also shownin Photo 2-15 illustrates the angular discordance and lackof basal conglomerateor regolith. AGE CONSTRAINTS FOLDS A period of post-Norian and pre-Toarcian contraction In the area of Navo and Rugose creeks, felsic tuffs of is well constrained by dated strata above andbelow the an- the Navo formation are folded into upright toinclined, open gular unconformity between Strata andQuattrin creeks. The to tight, gently southeast-plunging chevron folds (Figure4- vergence of the contractional event is difficult to determine,4). Where fold closures are absent, bedding-cleavagerela- but may have been northeast-directed if the attitudes of over- tionships suggest that the strata are tightly folded (Photo turned bedding represent fold vergence. Truncation of 4-9). Farther east, toward the ScudGlacier, decimetre-scale, steeply dipping Stuhini Group beds by the massive late upright, open to tight, north-trending foldsand smallerscale, Early Jurassic Dokdaon and Strata Glacierplutons may also parasitic minor folds occur in Lower Permian limestone. In indicate folding prior to theirintrusion. Farther south, in the contrast, a steep tovertical, northwest-striking bedding and Sulphurets area, a possibly correlative post-Late Triassic chlorite-sericite foliation characterizeargillite and siltstone and pre-Hettangian angular unconformity is marked by a of Carboniferous or Late Triassic age (Photo 4-8), in the basal conglomerate(Jack formation; Hendersonel al., 1992; Scud River valley. No fold closures were observed. Lewis er al., 1993). In addition to the upright chevron folds, southwest- verging asymmetric minor folds are commonin Navo Creek STRUCTURES NEAR SCUD GLACIER area (Photos 4-10.4-11). A gently inclined majorsynform, More intensely deformed and metamorphosed,undated with an amplitude of 3 kilometres, contains secondary S, Z upper greenschistto amphibolite facies metavolcanic rocks and M-type macroscopic folds exposed alonga cliff face on (Photo 4-7) resemble strata of the Stuhini Group and crop the north side of Rugose Glacier (area2 in Figure 44). The out around Middle ScudCreek, east of theScud Glacierand upper limb is truncated by a moderately to steeply eastdip- west of the Hickman Ultramafic Complex. Alternatively, ping reverse fault. Discrete zones of isoclinally folded cy- they may correlate with Carboniferous volcanicrocks of the lindrical corals, asymmetrically folded microscopic Stikine assemblage. Theyare characterized bymetre-scale, locally rootless, tight, upright, gently northeast to north- plunging folds developed in biotite schist and mafic metatuff adjacent to foliated pyroxenegabbro sills. Rare biotite lineations plunge gentlyto the south on moderate west- dipping foliation surfaces. Foliated and infolded recrystallized limestone and chloritic tuff are exposed east of the ScudGlacier. Here, an open, gently northeast plunging anticline is cored by Upper Permian limestone. Three kilometres farther south, limestoneis folded into open, gently southeast-plunging, southwest-vergent synform-antiform pairs disrupted by faults and at one locality intruded by the border phaseof the Hickman pluton. Well foliated to massive diorite related to the Hickman pluton locally cuts compositional layering. Asimilarstyleofminorfolding was observed in correlative rockson the northeast margin of the Strata Glacier pluton. A pendant of these folded metavolcanic rocks within thesouthwestmarginoftheYehinikoplutonconstrainsfold- ing as pre-Middle Jurassic (Photo4-7). The lower age limit is either Late Triassic or Carboniferous, depending on the lithologic correlation used (Stuhini Group or Carboniferous part of the Stikine assemblage). If the foliated gabbrosills are related to the Hickman pluton, then the deformation is younger than Late Triassic. This local deformation and metamorphism may be related to the intrusion of the Hick- man pluton or the more regionalLate Triassic to Early Ju- rassic event. Why the eastern border of the pluton is not equally deformed remains unknown.

MIDDLE JURASSIC OR CRETACEOUS CONTRACTION (D4) Two stylesof macroscopic folds,and northeast-dipping contractional faults north of the Scud River (Figure 4-4) are Photo 4-7. A pcndant of chevron folded metavolcanicrocks discussed below. They are believed to herelated to a Middle (Stuhini Group?) within massive granite of the Middle Jurassic Jurassic or Cretaceous contractional event. Yehiniko pluton (DBR88-206).

86 Geological Survey Branch Ministrv of Employment ond Investment

Figure 4-4. Schematic cross-section illustrating the contrast in deformation between fclsic tuff (Navo formation, uCSn and overlying Permian limestone succession (Ambition formation, IPSc). and the series of northwest-trendin:. reverse faults, including the Cone Mountain fault. Other abbreviations:uCSs? =possible Carboniferous strata (or Upper Triassic?);IPSa = argillite: UTSV= Upper Triassic Stuhini Group. The two styles of folding are illustrated hereas area 1 and 2; the tightcr, upright foldsin area 1 could be in the closure of a larger anticline. In fact, it may be the hangingwall anticline to the Cone Mountain fault.

Photo 4-9.Vicw to the south of bcdding-cleavage intersections in Photo 4-X. Typical steeply dipping to vertical foliation dcvcloped fclsic tuff (Navo formation), on the southwest limb of a shallow in Carboniferous (or Upper Triassic?) mctascdimentq rocks in southwest-plunging, upright synform (DBRXX-115). Pencil at top the Scud River valley (unit uCS?). of photo for scale, refracted clcavage is prominent.

.Balletin 95 87 bioclasts, dissolution fabrics and local pervasive cleavage are characteristicof some of the reverse faults.The folding and faulting imbricateand greatly thicken the limestone succession. Our previous interpretation invoked separate phases of deformation, producing upright folds and then asymmetric folds (Brown and Gunning, 1989a). however, we now suggest they are products of the same contractional event.

CONTRACTIONAL FAULTS A series of northwest-striking, subvertical to moderately northeast-dipping faults, including theCone Mountain fault, trend northwest from the ScudRiver north to the Ham- perpluton, and may extend as far north as theButtertlyLake fault (Figures 4-2.4-4.4.5). Contractional faults produced older-over-younger relationships in the Ambition Forma- tion limestone in the Rugose Glacier area, defined by fusulinid biostratigraphy, and by local overturned beds and asymmetric folds south of Rugose Creek (Figure44; Photo 4-10; Appendix 2). The reverse faults can be traced kil- 20 ometres to the south to Copper Canyon, where Permian limestone is structurally interleaved with Lower andMiddle Triassic shale and siltstone (Souther, 1972; Logan and Koy- anagi,1994).

CONE MOUNTAIN FAULT The ConeMountain fault is a zone of mylonitic granodiorite and foliated Stikine assemblage metavolcanic rocks 500 metres wide (Figure 4-5). Massive granodiorite in the footwall (Cone Mountain pluton) becomes increasingly strained over about 100 metres, and contains foliated grani- Photo 4-10. View northwest to asymmetric, southwest-vergent toid withdiscrete layersof ultramylonite in the zoneof high- fold in Lower Permian limestone(unit IPSc; DBR88-19). est strain (Photo 4-12). Northeast-dipping biotite and chlorite foliation rarely display east-plunging lineations.

Figure 4-5.Relationship of the Cone Mountain fault to the Cone Mountain and pluton hangingwall Stikine assemblage rocks. Southwest vcrgencc is basedon S-C fabrics,mica fishin the deformed pluton. Similar vergence for related reverse faullsin the Ambition Formation limestone is based on asymmetric folds and older-on-younger relationships dcfincd by fusulinid species which indicate stratigraphic repetition.

86 Geological Survey Brunch Ministrv of Employment and Investment

Photo 4-1 1. West-vcrging minor foldsio foliated mctamorphoscd tuffaccous rocks (Butterfly member;DBR88-52).

The hangingwall is foliated chlorite phyllite of the Stikine gashes. Theattitude of the mylonitic foliation relative to the assemblage (Figure 4-5). quartz veins suggests a reverse, southeast-directed sense of The deformed granitoid rocks display well-developed motion along the northeast-trending mylonite (Photo 4-13). S-C fabrics (Simpson and Schmid,1983) and rare mica fish NAVO SHEAR ZONE (Lister and Snoke, 1984) which indicate a southwest-directed sense of shear(Photo 4-12; Figure 4-5). Polygonized The Navo Shear zonemay be the northern extension of quartz grainsreflect ductile processes hut plagioclase crys- the Rugose fault in a similar way that the Cone Mountain tals have discrete microfaultsimplying brittle failure. The fault and Butterfly Lake faults arerelated. A 50 metre wide down-dip, biotite and chlorite stretching lineations reflect ductile and brittle shear zone, at thewestern contact of the the southwest-directed transport direction. This shear sense Daw pluton with adjacent Lower Permianlimestone is well is compatible with locally overturned, west to southwest- exposed in the headwaters of Navo Creek (Photo 4-14a. b). verging minor folds in the hangingwall Permian limestone It comprises recrystallized limestone with a subvertical fo- stratigraphy (Photo 4-10). liation and foliated diorite of the Davo pluton. Elliptical am- phiboliteanddiorite xenolithsareboudinaged and flattened, BUTTERFLY LAKE AND RELATED FAULTS and black basnlt dikes are brecciated and stretched within Discrete mylonite and cataclasitezones east of the mar- the diorite (Photo4-14a). gin of the Butterfly Lake syenite may be a northern extension of the Cone Mountain fault system. The most AGE CONSTRAZNTS prominent, the Butterfly Lake fault (Figure 4-2). is a steep, Most of the southwest-directed deformation is inter- north-trending brittle fault zone containing sheared and preted to be lateEarly Jurassicto Paleocene. It must be post- fractured mafic dikes and Carboniferous volcanic rocks. Triassic because Upper Triassic strata are folded into Polished fault surfaces along the mafic dike margins are ser- southwest-verging folds and faulted north of the Scud River. pentinized and talcose. If related to the Cone Mountain faull, Farther south, near Copper Canyon, Middle Triassic strata the Butterfly Lake structureshould be a dextral transcurrent are folded and faulted within correlative structures(Souther, fault. Oblique to the Butterfly Lake fault is a zone of north- 1972; Logan and Koyanagi, 1994). However, some pre- east-trending mylonitic syenite, 30 centimetres wide, that Early Jurassic movement is indicated along a north-trend- contains a chlorite foliation and en echelon quartz tension ing, gently west dipping, west-side-down fault and shear

Bdlerin 95 89 Brirish Colurnbiu

Photo 4-12. Photomicrographs comparing undefonnedIO mylor& tic Cone Mountain pluton; (a) Massive biotite hornblende granodiorite (DBR90-40); (b and c) Mylonitic granodiorite containing polygonized quartz grains and micro-faulted plagioclase grains. Crossed polarized light photographs above plane light images for each.

90 Geological S1,rvey Brunch I Photo4-13.Viewnortheast:othemyloniticButleerflyLakesyenite . - Carboniferous volcanic rock contact (Bullerfly formation, t DBR90-33).showing quartz tensiongashes which indicate a re- i versesense of movement. t

Photo 4-14. (a) View northwest to brecciated basalt dikcs and diorite within mylonilic diorite adjacent 10 the contact with Permian limestone. on the wcst side of the hcadwatcrsof Navo Crcck (DBR88-I). Flattuncd and aligned diorilelamphibolite schliercn foliation is rnoderalcly to steeply soulhwest dipping. Discrctc minor raulls dip modcralcly to the north and display reverse sense of motion where they displace the foliation and schilcrcn. (b) View southeast to rubvcrtical. southwcst-striking laycred marble immcdiately east of Navo 'Creck hcadwatcrs (DBR88-2). zone at Galore Creek where Early Jurassic metasomaticbi- NORTH-TRENDING FAULTS otite overprints ductile fabrics (Tom Heah, personal com- North-trending faults with poorly defined displace- munication, 1994).A younger, late Early Jurassic constraint ments are abundant in the Scud Glacier area, southwest of is provided by ductile deformation of the 185 Ma Cone Yehiniko lake, near Butterfly Lake and north of Stikinethe Mountain pluton. The upper age limit is providedby unde- and Chutine rivers. They include the Scud Glacier, Middle formed Eocene granite with blocks of folded limestone westScud Creek and Butteffly faults, Navo shear zone and co- of the StikineRiver. planar Oksa Creek dike swarm (Figure4-2). Some arereac- tivated faults with complicated reverse, normal and REGIONAL CORRELATION transcurrent movements, and locally mineralized. The relationship of the Cone Mountain fault systemto the regional strain pattern is unknown hut our age con- SCUD GLACIERFAULT straints for displacement overlap deformation associated The most prominent north-trending fault, the vertical with the Middle Jurassic King Salmon fault (Thorstad and Scud Glacier fault (previously interpreted as the southern Gabrielse, 1986) and the Late Jurassic to Tertiary Skeena extension of the Ambition fault by Brown and Gunning, fold belt (Evenchick, 1991b, c; Figure 4-1). The King 1989b). juxtaposes Permian limestone with Stuhini Group Salmon fault (sensu stricto) is mapped at the base of the west of Scud Glacier (Figure 4-2). implying over1200 me- Sinwa Formation (Souther, 1971), however, Takwahoni tres of east-side-down displacement. The fault zone com- Group strata farther south are foldedand faulted by the same prises a series of polished fault planes and a splay, deformational event. Therefore, the southernmostextent of containing 3 metres of clay gouge and en echelon pods of mafic volcanic rocks (Figure4- strain related to this deformationis indicated by the dotted rusty, sheared and polished 6). 3 kilometres northwest of the toe of the Scud Glacier. line on Figure 4-1. Southwest-vergence is dominant in the The polished fault planesare curviplanar, with horizontal to King Salmonfault and commonin the ConeMountain Struc- gently south plunging slickensides, which suggest dextral ture. Components of the Skeena fold belt. however, also transcurrent motion.A Miocene(?) basalt dike,1 to 5 metres havesouthwestvergence,forexampletheUnukRiverthrust thick, within and parallel to the fault has slickensided con- fault, which is interpreted to be linked, via back-thrusting, tacts, but is not dismemberedor truncated and was probably to the Sulphurets fault (Lewis, 1992). Thislast example il- intruded late in the development of thezone. lustrates that vergence does not differentiate specificStruc- Fault motion is post-Late Triassic. A small, altered, tural events. feldspar-porphyritic intrusion (possibly Eocene) cuts faulted, cleaved and altered StuhiniGroup rocks 3 kilome- FAULTS tres northwest of the toe of the Scud Glacier. The faultpro- jects southward toward the ScudRiver valley, where it may High-angle faults trend north, east, northwest and be plugged by another poorly exposed feldspar porphyry northeast and locally control map unit distribution (Figure intrusion. The fault extends southward beyond this body 4-2). Relative timingof movement on these fault sets isun- into the South Scud River valley and beyond (Loganet ul., clear. A seriesof north-dipping reverse faultsis orthogonal 1993b). To the north, the fault traceis covered by glaciers to the north-trending strike-slip faults. and icefields, butit may link with north-trending faults ex-

Riedsl theory main fault with horizontal slickensides 340174 NE S-plane S=023/72 SE cleavage c 023/78 SE 3 metre wide shear zone 234178 NW =c plane

chert pods (oriented 225175 NWI

1 (DBR90-211

Figure 4-6. Fabrics associated wilh the Scud Glacier faull; (a) Plan view of the main fault with deflected spaced cleavage indicating a right-lateral sense of displacement. Riedelmodel from McClay (1987); (b) 3 metre wide shear zone splay off main fault.

92 Geologicul Survey Branch Ministry of Employment and Investment posed alongthe west margin of the Yehiniko ultramafite, the faceous wacke, but bedding is rotated into the fault zone. Yehiniko fault zone. Movement on the Kitchener fault, presumably north side The Scud Glacier fault is interpreted to be a dextral down, is post-Triassic. oblique-slip fault. The sense of motion is basedon the ori- BOOMERANG AND RELATED FAULTS entation of the main fault zone relative to a spaced cleavage (Figure 4-6a)and the acute anglebetween the main fault and The east-trending, south-dipping Boomerang fault.lo- a conjugate gouge zone,3 metres wide.The coplanar Mess cated north of Boomerang Creek, bas Sustut Group sed- Creek fault zone,30 kilometres tothe east, was active from mentary rocks in its hangingwall and Hazelton Group Early Jurassic to Recent time (Southerand Symons, 1974). volcanic rocks in its footwall (Figure 4-2).The fault is not However, earlier sinistral motion is possible, as shown for exposed, but steep, south-dippingand vertical beds of Sustut the Tally Ho shear - Llewellyn fault to the northwestby Hart GrouparetruncatedagainstalteredgraniticdikesandHazel- andMihalynuk(1992).Theydescribeacomplex,long-lived ton Group volcanic rocks. The probable western extension transcurrent structure with ductile sinistralmotion between of the fault, on the west side of the Yehiniko Creek valley, 220 and about 180 Ma and dextral brittle displacement in is a shear zone10 centimetres wide, which offsets the con- middle toLate Cretaceous. The Hanymel -SouthUnuk fault tact of the Sustut Group and the Saffron pluton. The fault system may be analogous with early ductile sinistral motion contains zones of limonitic, brecciated granite and several (P.D. Lewis, personal communication, 1994). It is difficult 15-centimetre sectionsof clay gouge. It offsets the contact to assess the extentof reactivation on faults the in study area. approximately 500 metres in a left-lateral sense and may represent a south-dipping, oblique-slip shear zone.The Ter- MIDDLE SCUD CREEK FAULTS tiary or younger Boomerang faultmay be a reactivated Ju- A series of north-trending vertical faults parallel the rassic structure, because the Jurassic granitic dikes have a Scud Glacier fault and interleave Permian limestone, ma- similar orientation to the fault. roon tuff, chert and gabbro in Middle Scud Creek canyon. Narrow west-striking. subvertical and gently north dip- Limestone and tuff are steep to vertical. Local fault breccia ping extensional faults eastof the Scud Glacierand between northeastofMiddle ScudCreek 1 to2 metres wide, contains Quattrin and Strata creeks may be part of the Boomerang angular fragments of country rock. The faults extent south- system. The faultscut Stuhini Group andmost shownoah- ward where they are named “south Scud River fault zone” side-down displacement. A prominent, rusty weathering, by Logan and Koyanagi (1994). west-striking fault that juxtaposes Permian limestonewith Farther north, on the flanks of Mount Helveker,north quartz monzonite near the headwatersofMiddle Scud Creek andnortheast-striking.high-ang1enormalfaultsdisplacethe has horizontalslickensides,indicatingthatlatestmotion was basal contact of the Sloko Group by about 50 metres. Co- strike-slip. planar faults cut Sustut strata on Strata Mountain. Minor vertical displacements are also common on the series of DUCTILE FABRICS small north-trending faults cutting Permian limestonein the A series of discrete, east-trending ductile and brittle easternhalfoftheChutineculmination(Browneral.,1993). shear zones, each less than a metre wide. deform Early Ju- rassic diorite along Geology Ridge. Their ofsense shear and OKSA CREEKDIKE SWARM relationships to other structures is unclear, although similar The Oksa Creek dike swarm is a series of prominent, zones occur south of the Anuk River, 25 kilometres south- steeply dipping, north-trending, light grey weathering fel- east of Geology Ridge (Logan and Koyanagi,1994). Farther site dikes, up to 10 metres wide, that cut narrower, north- north, several discrete, east-striking mylonite zonesof foli- east-striking, black basalt dikesin the vicinity of Oksa and ated hornblende quartz diorite and chlorite schist are ex- Navo creeks (Figure 4-2). The dikes underlie as much as posed along the southern margin of the Castor pluton. 20% of a zone 2 kilometres wide, but they do not extend Adjacent Stuhini limestone and andesitic volcanics arealso farther north than Strata Creek or south of the Scud River. foliated. The dikes represent local but significant east-west extension, probably in the Tertiary perhaps related to back-arc JIMJACK FAULT SYSTEM (;.e. Coast Belt) extension. North-dipping Stuhini Group volcanic rocks are struc- EAST-TRENDING FAULTS turally overlainby concordant Permian limestone alongthe northeast-striking, moderately northwest dipping Jimjack KITCHENER FAULT ZONE reverse fault. It doesnot crop out. Triassic stratain the foot- The Kitchener fault zone is an east-trending zone of wall dip tothe north as imbricated, homoclinal faultpanels. subvertical faults within middle Triassic chert and the Permian limestone in the hangingwall farther northis com- Stuhini Group, and forms the northern boundaryof the Chn- plexly folded and upright, east-striking. tight to isoclinal tine River culmination.The zone is abouta kilometre wide symmetrical folds are most common. between the headwaters ofCave and Ugly creeks. The east- Movement on the Jimjack fault is post-Triassic (Stuhini ern extentof the zoneand its relationshipwith the south-di- Group) and pre-Eocene as the Sawback plutonis not faulted. rected Jimjack fault remains uncleardue to poor exposure. The faults may be correlative with northeast-striking con- Middle Triassic chert beds are folded into tight chevron tractional faults in the Tanzilla River area,15 kilometres to folds with amplitudes up to about 5 metres (Photo 4-4). In the northeast (Figure4-1 ), where Read(I 983) has described contrast, folds arenot evident in massive Stuhini Grouptuf- post-Eocene. normal displacement. Figure 4-7. Schematic cross-sections of the Sustut Group between Strata Mountain and Yehiniko valley, locations shownon Figure 4-8. Section I illustrates the gentle north-northeast gradient of the sub-Sustut unconfomity, and the structural complexity northeast of Mount Helveker. Section I1 shows the Saffron pluton reverse-faulted against the Suslut Group and the pronounced difference in elevation(1Mx) rn) of the basal contact across the fault.

Figure 4-8. (a) Distribution of Sustut Group in the Yehiniko valley and (b) interpreteden echelon left-stepping, dextral wrench fault system that may have produced lhe abrupt dip changes and reverse fault.

94 Geological Survey Branch ~~

NORTHWEST-TRENDING FAULTS cally more recrystallized than Late Triassic limestone,even Bedding of Sustut Group on Strata Mountain, Mount when CAI values are equal. Carnian conodonts in the Kirk and Mount Helveker is gently dipping to horizontak Tahltan Lake and Tahltan River areas have valuesof about however, northeast of Mount Helveker andin the Yehiniko 5, equal to those obtained from Lower Permian limestone Creek valley, beds strike to the northwest, dip steeply,and alongtheChutineRiver(Figures4-9,4-10).TheseCAIval- display abrupt reversals in dip direction. No fold closures ues of 5 to 5.5 are indicative of lower greenschist grade have been observed, except for a possible drag foldon the metamorphism (chlorite zone), with temperatures between eastern flank of Mount Helveker (R.T. Bell, written com- 300"and440°C(Rejehianefal., 19871.Thereisasignificant munication, 1989). A contractional fault that dies out into thermal contrast in Carnian rocks across the Jimjack fault, an anticline along striketo the northwest has been inferred with an abrupt drop to CAI values of3.5 or less, which in- to explain three features of the conglomerate:ahNpt the dip dicate zeolite facies metamorphism. This supports the inter- reversals, bedsdip underneath the older Saffron pluton;and pretation of the faultas a north-side-up reverse fault. the incipient cataclastic deformation of greywacke north- Some of the highest colour alteration indices are found west of Yehiniko Lake (Figure 4-7). adjacent to intrusions. For example, Upper Permian lime- A left-stepping. dextral wrench fault may have pro- stones have CAI values between 7 and 8, implying amphi- duced the contractional faultsand folds in the Sustut Group bolite grade, where intrudedby a Late Triassic diorite plug in this area (Figure 4-8).The distribution of preserved Sustut east of the toe of the Scud Glacier. Elevated CAI values also Group has a similar geometry to the Mess Creek graben occur west of the Tahltan Lake plutonand north of the Rug- (Souther, 1972) anda larger area southof the Grand Canyon ged Mountain and Half Moon plutons (Figure 4-10). of the Stikine River (Read, 1983; Wheeler and McFeely, In contrast to Paleozoic strata in the project area, Car- 1991). The basins and structures may he related to a latest boniferous and some Lower Permian strata farther lo the Cretaceous to early Tertiary right-lateral wrench fault sys- southeast near Newmont Lake show anomalously low CAIs Em, perhaps linkedto the terminal stagesof deformation in (Brown et al.. 1991). Late Triassic signatures are varied; .the Skeena fold belt. Carnian limestone values indicate an abrupt change from zeolite to greenschist grade across the JimjackthNst fault. :METAMORPHISM Norian values are uniformly within the zeolite facies, but are restricted in their distribution adjacent to the Hazelton Most rocksin the study area have undergone subgreen- outlier. Near Galore Creek, Middle to Late Triassic cono- !chistorgreenschist grade metamorphism. Primary textures donts have comparable values of about5 (Logan and Koy- are preserved in Mesozoic strata, but most Paleozoic rocks anagi, 1994). The fact that older rocks do not necessarily display some penetrative fabric whichhas obliterated origi- have higher CAIs demonstrates that the area has a varied nal textures. Pluton emplacement has partially controlled thermal history. This may be related to a combination of metamorphic mineral assemblagesin several areasand am- plutonism and regional faulting (Figures 4-9and 4-10). phibolite grade (hornblende hornfels) is attained locally (Figures 4-9,4-IO). The project area is divided into areasof LATE PERMIAN TO EARLY TRIASSIC(?) similar metamorphic facies based on conodont colour al- METAMORPHISM teration indices (CAI; Appendix 3).on petrographic identifications of metamorphic mineral assemblagesand on some The oldest metamorphic fabrics are pervasiveto faintly x-ray diffraction analyses (Appendix 10). Areas of green- developed penetrative phyllosilicate foliationsin Paleozoic schist facies correspondto CAIs greaterthan 5 and less than strata. Sericite and chlorite foliations are best developedin 7, and occur across the northern third of the Tahttan Lake the Little Tahltan take and Barrington River culminations. map area, northof the Jimjack fault, and souththe of Hazel- Foliation is less pervasive in the Chutine River and Scud ton outlier (Figure4-10). Zeoliteto lowergreenschist facies River culminations where Gunning (1993a) defines the r,xks with CAls less than 5 and greater than 1 underlie an greenschist assemblageas calcite, quartz, epidote (zoisite), area between Yehiniko Lake and the confluenceof the Chu- white mica and magnesium-rich chlorite (corundophilite). tine and Stikine rivers (Figure4-10). Local thermal anoma- Amphibolite and greenschist grade Carboniferous volcanic lies related to intrusions are evident throughoutthe area; for and sedimentary rocks in the Butterfly Lake area display example, Tahltan Lake and Scud Glacier areas. Zeolite moderately developed foliations. grade Stuhini volcanic rocks are common north of Mount Age constraints for metamorphism are poorly estab- Helveker and in the northeast-trending belt of rmks in the lished. We interpret the event to be pre-Middle Triassic in Srikine valley. Farther north. laumontite occurs in age, based on the presence of intensely deformed green- alnygdules and veinlets in Stuhini basalts near the Damna- schist grade rocks of probable Permianand older age,which tion pluton. are juxtaposed with less deformedand lower grade LateTri- assic strata, suchas in the Little TahltanLake culmination. CONODONT COLOUR ALTERATION INDICES The same contrastsare noted, butare less well expressed in The study of conodonts in Triassic and older rockspro- the other culminations.The foliations formed beforeor dur- vides an index of thermal maturationin the region. Carbon- ing DI recumbent fold development. as recognized farther ikrous and Permian limestone CAI values are similar, north in the Tulsequah map area (Bradford and Brown, averaging about 5, and indicating probable greenschist 1993a). The postulated pre-Middle Triassic metamorphic grade metamorphic conditions. Permian limestone is typi- event correlateswith a post-Early Permian. pre-MiddleTri-

- Bdlerin 95 95 0 'P 20

kiiomewer

Figure 4-9. Thermal maturation based on conodont colour alteration indices and metamovhic grade. Distributionof conodonts and their colour alteration index values are relatedlo simplified geology. Symbols illustrateCAI and thin section control pints with their facies. Data are grouped into five facies.DP =Damnation pluton, HMP= Half Moon pluton, RMP= Rugged Mountain pluton,TLP = Tahltan Lake pluton.

96 Geological Survey Branch Eorly-Middle Triassic

1 2 3 4 5 6 7 a CAI Temperature I I I 1 I I range I'CI 60-140360-550 300-480190-300 110-220 480-720

unmetamorphased Zeolite facies pumphellyite facies

Figure 4-10. Histograms illustrating the distributionof CAI values relativeto age. Temperature ranges are from Epsteiner nl. (1977) and Rejebian era/. (1987). assic low-grade metamorphic and deformation eventnoted truncateisograds within theTaklaGroup(Greenwoodetal.. by Read (1984) and Readet al. (1989) to the east andsouth- 1991). east, and more widely by Monger(1977b). EOCENE BURIAL METAMORPHISM JURASSIC TO PRE-LATE CRETACEOUS Petrography and limited x-ray diffraction analyses of METAMORPHISM rhyolite tuff and porphyritic basaltic andesite fromthe Sus- tut and Sloko groups identified zeolitesin fracture fillings Stuhini and Hazelton group rocks are characterized by and matrix (Appendix IO). Zeolites are probablythe product zeolite to lowermost greenschistgrade mineral assemblages of burial metamorphism. Similar conditions are evident (Appendix IO). There is no evidence of a regional pre- fromvitrinitereflectancedataforasampleofcoalifiedwood Hazelton (pre-Jurassic) metamorphic event affecting the from theSustut Group (Figure4-9) which fallsin the high- Stuhini Group that would correlate with the post- volatile bitumous coal series, with random reflectance (Rm) Norianlpre-Toarcian deformation discussed above. Vari- of 0.72 and mean maximum reflectance (Rmm) of 0.75. ations in metamorphic grade of Mesozoic strata tend to Similar rank Eocene coal occurs near Tuya River (1041/2,7: reflect proximity to plutons and localized heat flow. Lau- Ryan, 1991).Awhitecrystal-vitricrhyoliteashtufffromthe montite identifiedin the Stuhini Group near the Damnation Sustut Group produced a 51.6+1.8 Ma whole-rock K-Ar pluton limits the depth of burial to less than 11 or 12 kilo- date. This may represent the age of zeoliteburial metamor- metres (Lion, 1971). assuming a normal geothermal gradi- phism during Sloko volcanism. Uranium-lead dates of the ent of about 30°C per kilometre. Sloko Group 250 kilometres farthernorth are slightly older, The timing of the metamorphic event that affected at about 53 Ma (M. Mihalynuk,unpublished data). Stuhini and Hazelton stratais poorly constrained. Metamor- phic amphibolefrom theMoscovian volcanic unit(Butterfly CONTACT METAMORPHISM member) yielded a 155 Ma date by conventionalK-Ar tech- Contact aureoles adjacent to plutons extend up to500 niques (Appendix 12). however. it is unclear whether this metres from intrusive contacts. Secondary gamet-wollas- reflects the thermal peak or represents partial resetting dur- tonite skarns and biotite hornfels are common,and andalu- ing the Eocene plutonicepisode. Similarly. 166 and 148 Ma site wasidentified at Devils ElbowMountain. The strongest dates obtained from Aalenian and Toarcian volcanic rocks thermal effects occur adjacent to ultramafite bodies where are equivocal estimates for the metamorphic event. The secondary amphibole is common and biotite hornfelswell is thermal event was probably coeval with emplacement of the developed. This presumably reflects the higher tempera- Middle Jurassic Three Sistersplutonic suite. An upper age tures of emplacement of the ultramaficrock. Plutonic rocks limit is provided by overlying Sustut Group strata, which underlie more than50% of some pans of the map area and are less metamorphosed. Similiar relationships are evident the elevated metamorphic mineral assemblages reflect this in north-central British Columbia where Sustut Groupstrata plutonism.

- Bulletin 95 97 SUMMARY OF METAMORPHISM strata but did not generate penetrativefabrics. Zeolitespre- Late Permian to Middle Triassic and Middle Jurassic sent in the Stuhini Group in the Stikine valley and in the metamorphicevents are documented. A Permo-Triassic ~~~~l~~~ G~~~~ outlierindicate that L~~~~~i~~~i~ and greenschist grade event may have been synchronous with younger rocks were neverdeeply buried. This may corrob- regional deformation which produced chlorite and biotite phyllite characterizing stikine assemblage rocks in the rate stratigraphic evidence thatthe Stikine Arch remained a minations. The postulated Jurassic event affected Mesozoic topographic high for much of the Mesozoic.

98 Geological Survey Branch Ministry of Employmenr and Invesfmenr

CHAPTER 5 ECONOMIC GEOLOGY

The map area lies within an important metallogenic in the caseof transitional veins, some ofwhich may repre- province along the eastern margin of the Coast Belt, from sent distal parts of porphyry systems. Given the relatively Alice Arm north to theTaku River, that hosts numerous pre- undeveloped nature of most of the mineral prospects, any cious and base metal mineral deposits (Figure 5-1). Past classification of deposit types must be viewed as provi- mineral production in the project area has been limited to sional. placer gold mined along the Barrington River. The mineral Certain deposit types areassociated with particularstra- potential of the region is highlighted by the Schaft Creek tigraphic intervals orintrusive suites, while others represent and Galore Creek porphyry copper deposits, immediately widely separated mineralizing episodes. For example,in the east and south of the project area, where large, unexploited Stikine Terrane, submarine volcanic arc settingsfavourable copper resources havebeen defined. In this chapter, mineral for massive sulphide depositsdeveloped in Devonian, Car- Occurrences within the study area are classified according boniferousandMiddleJurassicsequences.Alkalineandcal- todeposit type,and age constraintsonmineralizing episodes calkaline porphyry copper deposits and transitional veins are summarized. Finally, recent exploration activity and vi- developed where plutons intruded oceanic arcs during the able explorationtargets are reviewed. Late Triassic and Early to Middle Jurassic. More evolved No mineral occurrences in the study area have publish- silicic porphyry deposits and epithermal veins are associ- ed reserve estimates, but exploration has been limited be- ated with Eocene continental volcanism andplutonism. cause the areais remote and rugged. Known showings are primarily concentrated in eight main areas: the Scud River, PORPHYRY DEPOSITS Schaft Creek, the Yehiniko fault zone, Dokdaon-Strata- Helveker creeks, Devils Elbow, Mount Conover, Limpoke Northern Stikine Terrane contains examples of three pluton and Tahltan Lake pluton (Figure 5-2). types of porphyry deposits, The Schaft Creek and Galore Creek deposits (Figure 5-1) exemplify calcalkaline and al- The most economically significant deposit types in kaline porphyries, respectively. The Ben showing is hosted northern Stikine Terrane are: alkaline and calcalkaline por- by Eocene plutonic rocks and has affinities with porphyry phyries; transitional and mesothermal veins; epithermal molybdenum deposits. Although significant metal re- veins; volcanogenic massive sulphide (VMS) deposits, and sources have been defined at both Galore Creek and Schaft skarns. Classification of someof the showings in the project Creek, neither has been developed. area is speculative dueto lack of data. This is most common Fifteen of the fifty seven mineral occurrences recorded in the MINRLE database for the project area are classed as porphyry showings (Table 5-1). All showings, with the exception of the Ben showing, are hosted by Stuhini Group volcanics and Late Triassicto Middle Jurassic intrusions. CALCALKALINE PORPHYRY COPPER DEPOSITS Calcalkaline porphyry copper deposits are associated with high-level lo deep-seated felsic intrusive bodies, generally occurring along convergent margins in oceanic or continental arc settings. Gold and molybdenum contents may be significant. Theassociation with calcalkaline intrusive suites is a fundamental characteristic. Typical features include annular or shell-like alteration zones with potassic (potassium-feldspar andlor biotite) cores and sericitic to propylitic outer zones (McMillan and Panteleyev, 1988; McMillan, 1992). Schaft Creek is the outstanding example in the northern Stikine Terrane. SCHAFT CREEK (LIARD COPPER) Schaft Creek is a high-level, calcalkalineporphyry copper-molybdenum deposit (Sutherland Brown,1971; Fox er Figure 5-1. Major mineral deposits, mints and pas1 producers al., 1976; Seraphim et 01.. 1976) located near the intrusive between Slewart and Tulsequah. contact between the Middle Jurassic Yehiniko pluton and ILEGEND

. .I hosted by mafic flows,su~vo~can~c'~n~rus~ons and dpiclas. resources are 910 million tonnes with an average gradeof tics of the Stuhini Group, with only 109'0 of mineralization 0.3%copper, 0.03% molybdenumand0.113 grampertonne in felsic dikesand quartz feldspar porphyry (Linder, 1975). gold (Linder, 1975). The size of the deposit makes Scbaft These were originally believed to be comagmatic with the Creek one of the largest copper, molybdenumand gold de- Yehiniko pluton. However, altered monzonite from drill posits in British Columbia.

IO0 Geolo&icul Survey Branch TABLE 5-1 SUMMARY OF MINERAL OCCURRENCES

hUN FILE NAME NTS HOST ECONOMIC HOST NTS NAME hUNFILE DESCRIPTION REFERENCES

037 Hicks lMG106 63562003794W Sluhini bn.cpy,Bleb$, rrringerr, and GEM 1971-72,Mwk Group mo. PY disseminationsofpyrite, (1910) chalcopyrite, bornite and lerrr molybdeniteoccurmsinly in Sluhini Gmupvolcanicr near the ea~lcmmargin ofths Hickman plumn.

063 Latc IMGi06 3788506368000 Stuhini Group/ Ychiniko plu~on

078 104Gi06 3768006366000 Swhini Group; Yehinika pl~ion

038,O;Y LLK, Dok 35 mal. ". cw. Oxidized disminated and Vcilch (1970). Mmd mo. PY fracure-filling chalcopyrite-(1990b) molytdcniw-pyrite is sccompanisd by propyiitis aitcration. 043 Dok 104G112 6381700345650 Stuhini Group

074 PR 3490WIMGiI? 679700 Swhini Group

m1 Poke

tmz Gordon 104Gi136410365 334119 Stuhini CPY Disseminated chalcopyriteis Hallof(1966). Marvd Group aswined with alkali feldspar (1%). Ken (IY48n). svenile dike swarms which Souther (19721

320674 63661 76 Tecniary sock

EIullerin 95 IO1 British Columbiu

MlNFlLE NO. NTS DESCNPTIONECONOMICUTM HOST (Lone09) REFERENCES (104G ) NAME MAP NORTHEAST MPUNIT MINERALS

140 337504 6364500Slikinearremblagc py.cpy.rph Quanr veins up to 1.5 m wide Kurhnsr (199% 1991): SI", po rtrike015"it~ddip60-65V Chung(l990a) castcrly within porphyritic volcanics.

138 342504 6354000Stikinc assemblage py.cpy. Mineralized quam~alcitevein Kasper (199%) vh in pyritic argillitesreturned valucrof50ppbAu.l.4ppm Ag. 691 ppm Cu. 6830 ppm 2".

139 338wo 6358500 Slikine nrremblagepy. po, Quanlveinrinlimerlonenre Chung(l990e) wh mineralilcd with pyrite, pynholile, chalcopyrite and sphalerite.

056 NmhScud, 356387 6362368Sluhini Group Alicia Otis, Moped

111 Ychiniko East 361523 6373332Stuhini Group/ Ychiniko pluton

I12 Yehiniko West 359M)O 6382000Stuhini Group

129 Chuckster 353660 6377330Stuhini NNE-lrending, rtccply dipping new ossumnce Group carbonate-quanrveinlers14 (CGR89-307: cm wide in a 5 m-wide lone Appendix 14)

I34 354563 6379169Stuhini G

135 353336 6379465Stuhini GCOW

136 354555 6379720Stuhini A 077184SE trending. "EW 0CE"rrS"EC Group diwoniinuour quam vein, up(DBR89-302; ADDendix 14)

010 347400 6390250Stuhini GWP

019 Mtn. Goat, Kirk 348744 6390502 Suhini or Hareiton CP?,bn C" bornim.

I30 Steep Crcek 26971 6389455Sluhini PY. CPY? Group

ow Jackson, BIK, 339250 Conover Ck.

025 Lady Jane 338350 6395650 Suhini croup

102 Geological Survey Branch Minisrry of Emplynenl and lnvesrmenr

MINflLENO. NTS UTM (Zonc09) ECONOMICDESCIUPTIONHOST REFERENCES (LMG I NAME MAP NORTHEAST MAPUNIT MINERALS

o&I 104GI13 334512 6392515 Stuhini CP? Group

065 104Gl13 331200 6392700 Sluhini PY. Po. CP? GRWl

006 104Gl06 368378

007 104Gli I 365200

020 IWGII2 3373m 085

127 IMGII2 357610

I 49 IaKil13 325064

075,084 Gu,Gu Nonh 104Gi05 347000 63715W Strata Glacier plulon

058 Marg W'ert 104GIO5 347500

089 Marg Earl 348150 6371640 Sluhini Grovp

128 Forril Vein IWGIlI 351657 6384893 Sluhini Group

131 Dikcr 104Gl12 350289 6386230 Hazellon Group British Columbia

MINFLLENO. NTS UTM (ZoneO9) ECONOMICHOST REFERENCESDESCRIPTION (104G ) NAME MAP NORTHEAST MAPUNIT MINERALS

I32 Forgollen 104GllZ6383521 349343

I33 Captain 104Gl12 347412 6385901 Pyritcshalcopyrite occurs in DCW o~~umnce cm-scalr quam veins. (DBR89-273.277-3, 277-2: Appendix 14) .. 104G113 331080 6404200

Sliprn showings: 081,082, VB20,VB5, 104G113 342250 6425670 083. VB 12

01 I Drapich 104Gl12 339200 638930C

012 Devil'sflbow 104G112 339998 6383841 Stikine-mblage mag, py, SI", lrregularsulphidc lenrer~efurMandy (1930),Kerr epy. rph. wh. PO in skam developed at a (1948a),Ksp(l983), crancdiorirc contact. Llovd (1989). DUM

013 Ape* 104Gl12 340340 63794M

062 COS 104Gl05 341012 6355104

141 JDI. Scud River, lMGlO5 348559 6351591 CBI.CB2

151 Mas l04Gll3 324558 6425807 Sluhini mag Gm""

104 Geologicol Survey Branch Minisry of Employment and Invesrmnf

MlNFlLE NO. NTS UTM (Zone@% HOST ECONOMIC DESCRIPTION REFERENCES (IMG NAME MP €AST NORTH MAPUNIT MINERALS

Placergold depoil: 008 Barringtonfiver lMGl12 3352W 64026(10 Qal

SHOWINGS NEAR SCHAFI CREEK nite(Table5-1:LLK,Dok35,DokandPR;MINFILE104G The most significant concentrationof calcalkaline por- 038,039,043,074). Mineralized veins occur in propylitic phyry copper showings in the project area extends noxth and potassic alteration zones associated with north-north- from the Schaft Creek deposit along the eastern margin of east and northeast-striking, pink graniteto syenite dikesin- the Yehiniko pluton. These include the Late and ArcPost truding Stuhini volcanic rocks. These dikes may be (MINFILE 104G 063 and 078) and Nabs prospects (104G comagmatic with the Middle Jurassic Saffron pluton. This 030, 031 and 032). The Hicks showing (104G 037), just area has good potential for discovery of additional copper south of Schaft Creek, alongthe eastern contact ofthe Hick- and gold mineralization. man pluton, may also be related to this suite. Mineralogy consists of pyrite, chalcopyrite, magnetite, bornite and rare ALKALICPORPHYRY COPPER DEPOSITS molybdenite as disseminations along fracture zones and Alkalic porphyry copper deposits occurin Late Triassic sheared intrusive contacts. Silicification and propylitic alteration arepresent.Mineralization wasprobablycontrolled to Jurassic rocks Of Quesnellia and the northern by north-uending near the margins of [he Hick- StikineTerrane, where high-level monzonitic tosyenitic man and Yehinikoplutons. stocks and plugsintrude comagmatic volcanicswhichcom- monly have shoshonitic affinities. Magnetite-rich breccias, DOKDAON - STRATA CREEK AREA potassic and albite-epidote alteration and a molybdenum- Strongly oxidized pyritic alteration zones between poor, copper-gold metallic suite are typical features of alka- Vokdaon and Strata creeks contain several showings with lic systems. as exemplified by Galore Creek, just south of disseminated and fracture-filling chalcopyrite and molybde- the project area.

13ullerb1 95 105 -._ .

British Columbia

GALORE CREEK The Ben showing has similarities to better known deposits Mineralization at Galore Creekis associated with sev- in the Alice Ann area, south of Stewart (e.g. Kitsault). eral phasesof potassium feldspar megacrysticsyenite dikes Two types of mineralized boulders were foundsouth of and sills of the Copper Mountain suite, which intrude the Ben prospect,along Deeker Creek,in thecourse of this Stuhini Group volcaniclasticsand pyroxene and orthoclase- project. The first consistsof rusty weathering, semimassive phyric flows and breccias (Allen et al., 1976; Logan and to massive pyrite layersin fine-grained, white vuggyquartz Koyanagi,1994).Potassicandpropyliticalterationsuitesare (Photo 5-2). The second is a manganese-stained, vuggy present, and andradite to grossularite garnet is widespread. quartz-carbonate vein and breccia with disseminated chal- Mineralized zones contain abundant pyrite, chalcopyrite, copyrite. galena and pyrite. The latter vein type forms a magnetite and bornite, with local secondary cuprite and boulder train that Ashworth Exploration Ltd. traced (in covellite. Published drill-indicated and inferred reserves of 1990) southwest to an area coveredan byunnamed glacier. 113 million tonnes grading 1.06% copper,0.45 g/t gold and The sourceof the mineralized boulders isnot known. 8.6 g/t silver make Galore Creek oneof the largest deposits of its type (Allen e? al., 1976). MESOTHERMAL AND TRANSITIONAL RUGGED MOUNTAIN PLUTON VEIN DEPOSITS The Rugged Mountain pluton is classed with the Cop- Mesothermal vein systems occur in both ductile and per Mountain suiteof Late Triassic to Early Jurassic alkalic brittle shear zonescommonly associated with regional fault intrusions. Anomalous but relatively low copper and gold systems. Most vein systems probably developed at a depth values are reported from the clinopyroxeniteborder phase wherethetransitionfromductilesheartoseismogenicbrittle and from isolated rusty weathering pyrite-malachite altera- failure occurs (Sibsonef a[., 1988). This level is afunction tion zones (upto 2.32% Cu and 1.57 g/t Au; Marud, 1990b). of temperature and fluidpressure and isstrongly affectedby The presenceof alkalic inmsions at Rugged Mountain sug-intrusive and regional deformational events.Vein systems gests an analogous setting to GaloreCreek; however, pros- at higher crustal levels, above the brittle-ductile transition pecting to date has foundonly low copper and gold values zone, may be produced by high fluid pressures associated and weak alteration. with devolatilizing magmatic bodies or associated wallrock LIMPOKE PLUTON reactions. These veins areof economic interest wherethey contain high gold values, although significant base metals Several copper showings peripheral to the Limpoke may be present. pluton may represent alkalic porphyrymineralization (Table 5-1:Gordon,Poke,NewLimpoke;"RLE104G001.002, The northern Stikine Terranecontains numerous exam- 024). Disseminated pyrite and chalcopyrite occur within ples of such "transitional" veins, manyof which are associ- fracture zones in altered SNhini Group volcanics, in alteredated with Early Jurassic intrusions. To the south, in the quartz monzonite to monzodiorite, and in altered zones as- Stewart-Iskutbelt, the Premierand Sulphurets depositsare sociated with potassium feldspar porphyritic syenite dikes. hosted by Early Jurassic Hazeltonvolcanic rocks associated with coeval calcalkaline potassium feldspar megacrystic Potassic alteration @iotite and potassium feldspar) affects both intrusiveand adjacent volcanic rocks. Potassium feld- sills and dikes of the Texas Creek suite. Mineralizationoc- curred during the Early Jurassic (about 190 Ma), based on spar porphyritic syenite is mineralized at the Gordonshow- U-Pb dates fromgenetically associated intrusions (Alldrick ing. Minor molybdenite is present at the New Limpoke showing, while bornite occurs at the Gordon showing. Re- et af., 1986, 1987; Brown, 1987; Alldrick, 1993).The Snip cent sampling on these zones returned low precious metal deposit in the Iskut area is a goldand base metal rich vein values (Marud, 19%). within a brittle-ductile shear zone.It is hostedby Upper Tri- assic Stuhini(?) greywacke that is intrudedby the Red Bluff PORPHYRY MOLYBDENUM DEPOSITS porphyry, an Early Jurassic altered potassium feldspar Porphyry molybdenum deposits are distinct from megacrystic body that is elongated subparallelto the shear 1992).The calcalkalie copper porphyriesin ore mineralogy, tectonic zone(Macdonaldetol.,1992;RhysandGcdwin, Golden Bear deposit, northwest ofthe project area, consists setting, intrusion composition and alteration suites.are They generally related to granitic hypabyssal intrusions in of gold-bearing silicified Permian carbonate lenses and pyriticgougeincontactwithTriassicoroldermaficvolcanic extensional settingsin cratons or highly evolved arcs, and rocks along a north-trending strike-slip fault. Although no are copper and gold poor. Mineralization is associated with intense silicificationand phyllic alteration. Early Jurassic intrusions are exposed,an Early Jurassic age of mineralization is inferred from severalK-Ar dates onal- BEN - DEEKER CREEK AREA teration zones (Schroeter, 1987). The Ben porphyry molybdenum occumence(Table 5- 1: At least 22 of the 57 mineral occurrences recorded in Ben; MINFILE 104G 014) is within a zone of argillic and MINFILE for the project area canbe classified as transitional silicic alterationand manganese staining,up to IOM) metres or mesothermal veins(Table 5-1). Porphyry occurrencesare wide. Quartz stringers with disseminations of molybdenite preferentially hosted in Upper Triassic Stuhini volcanic and lesser chalcopyrite, pyrite and tetrahedrite, are hosted rocks and intrusive rocks of various ages. Structural fea- by a tine-grained felsic intrusion of probable Tertiary age tures, in particularhigh-angle fault systems,and proximity and biotite graniteof the Eocene Sawback pluton. The large to Jurassic and Tertiary inmsions, are more significantcon- oxidized alteration zone is a prominent feature (Photo5-1). trols than stratigraphy. The orientation of veins varies

- I06 Geological Survey Branch Minimy ofEmployrnenr and lnvesrmenr

Photo 5-1. Aerial view of propylitic alteration zone at Bcn Mo-Cu-W prospect (MINFILE 104G/014). drilled in 1971 but little work has been done since. Quartz-sericite alteration and stockworks with disseminated molybdenite, chalcopyrite and pyrite occur along the northwest-trendinz faulted intmsive contact of an Eocene .~ranite/Tclsite intruded into the Middle Jurassic Geology Ridge diorite that contains pendantsofPermian(?) limestone. widely from area to area, with north, northeast and north- been obtained from the Chuckster vein, where a grab sample west-trending fault systems being most prominent. ran 136 g/t (Photo 5-3a. b). Thin quartz-carbonate veins car- Seven mineralized districts contain most of the vein rying chalcopyrite and galena at the Plum occurrence are showings: Scud River, Yehiniko fault zone, north of the illustrated in Photo 5-4. Strata Glacierpluton, pendants in the Strata Glacier pluton, HELVEKER CREEK north of the Strata Mountain pluton, Helveker Creek and Several auriferous quartz-chalcopyrite vein showings Conover Creek. Twoof these districts are tentatively classed as Eocene (pendants in the Strata Glacier pluton and north are hosted by Stuhini Group volcanics south of the Stikine of the Strata Mountain pluton); the rest probably result from RiverintheHelvekerCreekarea(Table5-1:August.Moun- Early to Middle Jurassic events. fain GoaUKirk. Steep Creek; MINFILE 104G 010, 019, 130). These northeast-trending veins parallel nonheast- EARLY TO MIDDLE JURASSIC trending faults in the Stikine River valley. Exploration of one of these veins in the 1920s included driving an adit YEHINIKO FAULT ZONE (Mandy, 193 I ). Copper occurrences reported by Souther (1972) in the CONOVER CREEK upper part of both forks of Yehiniko Creek (Table 5-1: Ye- hiniko East and West; MINFILE 104G 111, 112) are prob- In theConover Creek area,plymetallic quartz-carbon- ably related to north-trending faults marginal to the ate veins and breccia zones occurnorth and west of the Mid- Yehiniko pluton. Little else is known about these occur- dle Jurassic(?) Conover pluton (Table 5-1: Lady Jane, rences. Jackson, ConoverMountain and Mist; MINFlLE 104G 009. 025, 064 and 065). The Lady lane vein, traced over 350 NORTH OF THE STRATA GLACIER PLUTON metres, strikes north and dips about 60" west (Dirom, 1964). Four polymetallic quartz-carbonate vein showings are In contrast, the smaller and less extensive Jackson veins, hosted by Stuhini Group volcanics north of the Early Juras- strike northwest to north (;bid.).Veins are associated with sic Strata Glacierpluton (Table 5-1: Chuckster, Plum, Mist, silicification and iron carbonate alteration. The two vein Player; MINFlLE 104G 129, 134, 135, 136). Veins gener- systems were describedby Mandy(1930) and Kerr(1948a). ally trend northeasterly in this area. High gold assays have The northeasterly elongation of the pluton may indicate co-

107 Photo 5.2. Vuggy, coarsely crystalline quam vein with disseminated pyrite, chalcopyrite and galcna, ncar headwalenof Deeker Crcck (MINFILE 1MG-014; DBRBB-I 13-1). Wallrock fragments arc argillically altered intrusive rock

Ph 010 5-3. (a) Gold-rich (136 g/t Au) Chuckstcr vein of intergown prismatic quarcz nccdlcs with disseminatcd chalcopyrite, pyrite and trace galcna, cutting Stuhini Group cpiclastic rocks, hcadwatcrs of Slratn Creek (MINFILE 104G-129; CGR89-307-2). Photo 5-3.(h) Silicified and potassically altered Middle Jurassic(?) plutonicrock with chaledonic quartz-carbonate vein containing pyrite and galena that assayed 5 g/t gold, bctwecn Strata and Dokdaon crecks(CGR89-411).

Photo 54.Multiphase veins - sheared quartz, disscrninnted chalcopyrite-pyrirc, and carbonatc-galena,1 kilometre cast oi headwaters of StralaCrcck (MINFILE 1046-134; DBR89-298). eval inbusion and activation of northeasterly trending faults A larger north-trending belt of Tertiary mineral show- with allied hydrothermal activity. The veinsystems arecon- ings canbe defined parallel to the Navo Creek- Strata Creek trolled by brittle shear zones conjugateto the regionalstmc- dike swarm, and extendingas far north as Mount Helveker, mal trends. which is cappedby Sloko Group volcanics. The dike swarm suggests the possibility thatSloko Group rocks were depos- SCUD GLACIER AREA ited along the entire length of this belt, and subsequently The Otis and Moped showings are gold-bearing eroded southof Mount Helveker. Mineralizationin the sub- arsenopyrite-quartz stockworks and veins along a west- Sloko basement consists of transitional veins, with higher striking, north-dipping fault zone (Johnson and Jones, level epithermal mineralization having been removed by 1990a. b, c). In addition to theveins, two modes of possible erosion. porphyry-style mineralization have been identified; lenses and fracture fillings of massive chalcopyrite, bornite and EPITHERMAL VEIN DEPOSITS pyrite, and disseminated chalcopyritein mafic tuff (ibid.). Given their high-level setting,epithermal depositstend The Alicia occurrence (previously known as the “North to be associatedwith specific stratigraphic intervalsand vol- Scud”; Gale, 1964) lies onthe west sideof the Scud Glacier; canic facies rather than with particular intrusive episodes. it appears to be an extension of the Otis and Moped mineralized zone (Johnson and Jones, 1990a, b, c). On the east side of the glacier and around Middle Scud Creek, narrow and discontinuous quartz - iron carbonate veins carrying chalcopyrite, tetrahedriteand pyrite cut metavolcanic rocks (Photo 5-5).

LIMPOKE GLACIER AREA A quartz-sulphide boulder train was tracedby Cominco Ltd. from the Limpoke Creek valleyto the southern edgeof the Limpoke Glacier where three typesof mineralized boulders were identified quartz-sulphide, massive pyrrhotite- pyrite-chalcopyrite-sphalerite-galena, and zinc-bearing quartz-carbonate (MINFILE 104G 149; Westcott, 1989b). Geochemical and geophysical surveys, geological mapping programs and four diamond-drill holes havebeen completed along the south side of the glacier (Aspinall et al., 1990, Aspinall, 1991).

EOCENE PENDANTS IN THE STRATA GLACIER PLUTON Stuhini Group roof pendants in the Early Jurassic Strata Glacier pluton host several polymetallic quartz-carbonate vein showings (Table 5-1: Gu, Gu North, Marg West and Mag East; MINFILE 104G 075, 084, 058 and 089). The occurrences are located just east of a major north-trending felsic dike swarm of probable Eocene age, that extends from the headwatersof Navo Creek to Strata Creek. Felsic dikes crop out near the Margshowings. Mineralization consistsof pyrite, chalcopyrite, molybdenite, sphalerite, galena and scheelite in sheared and silicified zones. The proximityof the felsic dike swarm and the presence of tungsten mineralization suggest that these showingsare Eocene in age.

NORTH OF THE STRATA MOUNTAIN PLUTON Scattered vein mineralization occurs in Hazelton Group and Stuhini Group volcanicsnorth and east of the Middle Jurassic Strata Mountain pluton (Table 5-1: Fossil Vein, Dikes, Captain, Forgotten; MINFILE 104G 128, 131, 132, 133; Photo 5-6a, b). Felsic dikes of probable Tertiary age have been mapped near the Captainand Fossil Vein show- Photo 5-5. Narrow (10 cm), north-trendinkquartz -iron carbonate ings. Further, lead isotopes fromthe Forgotten vein plot in breccia zone containing minor chalcopynte, malachite and green the Tertiary cluster of Godwin et a/. (1991). suggesting a mica hosted by Stuhini mafic volcanic rocks. Listwanite alteration possible Eocene agefor mineralization in this district. is common in Stuhini Group mafic volcanic rccks (DBR88-187).

110 Geological Survey Branch ~ ~~ ~~~ ~ ~ ~~

Although no epithermal systems have been describedin the TAHLTAN LAKE map area, regional considerations suggest the potential for The Tahltan Lake copper skams (MINFILE 104G 081, epithermal gold associated with Jurassic and Eocene rocks. 082) and the newly discovered Mag skarn are hosted by The Skukum deposit, south of Whitehorse, is hostedby Eo- Stuhini Group tuffaceous sedimentary rocks intruded by cene intermediate to felsic volcanic rocks correlative with diorite to granodiorite plutonsof probable Late Triassic age. the Sloko Group. Numerous small deposits occurin domi- At Tahltan Lake, skarn occurs overan area 400 metres wide nantly subaerial andesitic to dacitic volcanics of the Early by 800 metres long (Marud, 1990a).Sulphide-bearing zones Jurassic Hazelton Groupin the Twdoggone district, eastof are 1 to 2 metres wideand up to 5 metres long. The northem theB0wserBasin.h thelskut Riverdistrict,epithermal sys- part ofthe skarn contains specular hematite theand southern tems are found in Hazelton Group volcanics in the Treaty part is principally magnetite with minor pyrite(D. Marud, Glacier area, andthe Eskay Creek deposit (Figure5-1) has personal communication, 1991). This change from reduced affinities with both volcanogenic massive sulphideand epi- conditions close lothe intrusion to more oxidized conditions thermal systems. farther from the contact is analogous to the Craigmont de- Although none of the vein systems in the project area posit (Rennie, 1962; Morrison, 1974). can beclassifiedasepitherma1,prospective Jurassic and Eo- cene stratigraphy coversa limited area north of Strata Creek.DEVILS ELBOW Structural levels south of Strata Creek and north of the Polymetallic skarns at the Devils Elbow, Apex and StikineRiverareprobablytwdeepforJurassicandyounger Drapich showings (Table 5-1: MINFILE 104G 12, 13, 11) epithermal mineralization. occur in Paleozoic volcanic and sedimentary rocksjust east of the Eocene Sawback pluton. The Lucky Strike, located southwest of the Drapich showing nearthe Sawback pluton, VOLCANOGENIC MASSIVE SULPHIDE isapolymetallic transitional quartz-vein showing.TheDev- DEPOSITS ils Elbow showing contains scheelite in discontinuous In northern Stikine Terrane, Kuroko depositsknown are lenses of disseminated sphalerite, galena, chalcopyrite,py- to occur in Devono-Mississippian and Jurassic arc se- rite and pyrrhotite that are up to 15 metres long and 1.5 quences. The Tulsequah Chief deposit, in the Taku River metres wide. It is hosted hy Upper Carboniferous Stikine area (Figure 5-1). is associated with Early Mississippian assemblage limy siltstone, argillite and limestone intruded rhyolite of the Stikine assemblage (J. Mortensen, written by Middle Jurassic(?) hornblendegranodiorite(Dunn, 1990, communication, 1992). At Eskay Creek, Early to Middle Keep, 1983; Wehster and Ray, 1991). The showings have Jurassic volcanics of the Hazelton Group host gold-rich been intermittently explored from about 1910the to present. massive sulphides near the stratigraphic transition from an In 1915 numerous trenches and three adits were driven (90 active volcanic arcto a starved basin setting (Andersonand m long at603 m elevation, 18 m at 648 m. and 6 m at 672 'Thorkelson, 1990). m; Kerr, 1948a). In 1952, tungsten ore was mined hut never shipped, and additional prospecting was conductedin 1970, No volcanogenic massive sulphide occurrences are 1982 and 1989 (Lloyd, 1989). In 1990 the Northair Group lcnown to occur in Stikine assemblage or HazeltonGroup in prospected and mapped the area; Dunn (1990) concluded the project area. However, gold-bearing massive sulphide that the skarns were small and contained little gold. Lead occur in the Stuhini Group on the Goat claims, north pods from the Devils Elhow showing plots within the Tertiary of Tuffa Lake in the headwaters of Cave Creek (MINFILE cluster of Godwin et al. (1991). suggesting a genetic linkto 1104G121). They contain pyrrhotite with minor chalcopyrite the Sawhack pluton, and confirmingthe link between Ter- and gold assays up to40 g/t (Strain, 1981; Korenic, 1982a). tiary systems and tungsten mineralization, as inferred above Other styles of mineralization on the claims include quam- in the discussion of Eocene transitional vein deposits. c:arbonate veins with pyrite, arsenopyrite and chalcopyrite and pluton-hosted massive magnetite pods (Lehtinen, 1989; At the Drapich showing, sheared massive sulphideand Van Angeren. 1991). garnetite skarn is developed in Permian(?) Stikine assemblage limestone intruded by Middle Jurassic(?) hornblende granodiorite. Two adits (20 m and 8 m long) were driven SKARN DEPOSITS along the mineralized contact in the 1930s. Sulphides include pyrite, pyrrhotite, chalcopyrite, sphalerite and minor Widespread carbonate-rich volcanic-sedimentary se- galena. The showing was resampled in 1988 (Davis, 1988). quences inuuded by dioritic to granitic plutons suggestthe potential for significant skarn mineralization in northern SCUD RIVER Stikine Terrane.The best known example is the McLymont A number of vein and skarn showings have been dis- northwest zone, south of the project area, an oxidized (ret- covered in a northwest-trending belt northeastof the Pere- rograde) gold-bearing skarn in Carboniferous Stikine as- leshin pluton,in the Scud River area(Table 5-1: Oksa Gold, semblage tuffs and sediments (Ray eral., 1991). Snow, Cos, Jameson, JD-1, JD-3 and CB-1, CB-2; MIN- Several copper-iron and polymetallic skarn showings FILE 104G140, 139,062,138, 141). Most of these are re- occur in Paleozoic and Upper Triassic volcanicand carbon- cently discovered occurrences, consisting of gold and ate sequencesin the projectarea. Themain clusters of skarn silver-bearing quartz veinsin Stikine assemblage sedimen- mineralization are copperskarns relatedto the Tahltan Lake tary and volcanic rocks, with pyrite, pymhotite, chalcopy- pluton and polymetallic skarnsin the Devils Elbow area. rite. sphalerite and galena. The Split zone, in skarn-altered

Bdlerin 95 I11 Brirish Columbia

Photo 5-6. (a)Pyrite euhedra within iron carbonate quam vcin.immediately west of StrataMountain (MINELE 104G-1323 DBR89-382). note undefonned naturein contrast to (b). (b) Ductile and brittledeformation in quartz-pyrite-chalocopyritevein, west-northwest of Strata Mountain (MINFILE 1WG-133; DBR89-277-2).

II2 GeoIogicaI Survey Branch ~~~~ ~~~ ~~ ~ ~ ~~ argillite along the contact with a granodiorite intrusion, TIMING OF REGIONAL comprises massive to weakly banded pyrite, pyrrhotite, METALLOGENIC EVENTS sphalerite. chalcopyrite and minor galena (Kushner, 1991). Outwash boulders of garnet-actinolite skam found at the Regional metallogenic analysis supports links between headwaters of Rugose Creek contain disseminatedto mas- a number of metallogenic events and specific stratigraphic intervals and intrusive episodes.By far the most significant magnetite, pyrrhotite and minor chalcopyrite. sive pyrite, metallogenic period spans the Late Triassic to Middle Ju- The Rugose Glacier covers the contactwhere granodiorite cuts Early Permian limestone, the probable source area for rassic (about 203-175 Ma). the float. Geochemical analyses of samples from these boulders are included in Appendix 14 and Ross (1989). These PALEOZOIC: VOLCANOGENIC MASSIVE showings may be related to the Early Jurassic Pereleshin SULPHIDE DEPOSITS pluton or the Cone Mountain pluton. The Cos showing is a Paleozoic arc rocks containing felsic volcanic se- copper skam developed at the contact of the Pereleshinplu- quences and associated Kuroko-type volcanogenic massive ton with Stikine assemblage limestone. A genetic link be- sulphide deposits arewidely distributed in “McCloud belt” tween the pluton and proximal skarn and distal vein terranes (Miller, 1987; Brown et al., 1991). In northern showings is likely. Stikine Terrane,the Tulsequah Chiefand Big Bull deposits are the most significant examples. Tulsequah is probablyof Devono-Mississippian age; rhyolitein the footwall yielded OTHER DEPOSIT TYPES a zircon U-Pb date 350.6+14.7/-6.2of Ma (J.K. Mortensen, in Sherlock et ol., 1994). Felsic arc volcanics are also re- PLACER GOLD gionally prominent in Upper Carboniferous to Lower Per- Placer gold accumulations in gravels immediately mian sequences, although no VMS showings of this age south of the Barrington River canyon(MINFILE 104G008) have been found. Elsewherein the McCloud belt, Lowerto have been worked intermittently since the late 1920s. Re- Middle Devonian bimodal volcanicsin the eastern Klamath ported gold recovery in 1933 was 3.1 kilograms, and 6.8 Terrane of northern California (Copley greenstone and the kilograms in 1935 (B.C. Minister of MinesAnnual Reports Balaklala rhyolite) formedin an extensional arc setting and 1933,1935).Morerecently,BarringtonGoldLtd.purchased host several deposits (Lapierreef a!., 1985). Ithe placer claims from Integrated Resources Ltd. and now mines the deposit on a seasonal basis. Test mining in 1990 LATE TRIASSIC TO JURASSIC PORPHYRY lproduced 12.4 kilograms ofgold from about 36 000 cubic DEPOSITS AND TRANSITIONALTO ]metres of gravel (Integrated Resources Ltd., News Release, EPITHERMAL VEINS October 21, 1991). Thegold occurs as flakes that are 5 mil- Upper Triassic Stuhini Group volcanics and Late Tri- limetres in diameter and smaller. The lode source of the gold assic to Early Jurassic Copper Mountain suite alkalic intru- is thought to lie within the Barrington River or Limpoke sive complexes host significant porphyry copper-gold Creek watersheds, probably associated with marginal deposits like Galore Creek.At Galore Creek, K-AI dates for phases of the Limpoke pluton. hydrothermal biotite associated with mineralization range from 177 to 201 Ma (White et al., 1968). Lack of zircons !?TRATABOUND URANIUM has thwarted attemptsto date the Galore trachytesby U-Pb Uranium occurrences on the He1 claims (MINFILE techniques. Itis probable that theage of emplacement of the 1.04G109) are hosted by Sustut Group conglomerate and Galore intrusions is closer to the older biotite alteration sandstone near Mount Heleveker. Theyoccur as secondary dates. This is supported by a 204+10 Ma K-Ar date fromthe rninerals in conglomerate. as radioactive coaly fragmentsin Pereleshin pluton, believedto becoeval with the Galore in- s,andstone, and as radioactive Sloko Group trachyte talus trusions. The Rugged Mountain pluton has geochemical (Bell. 1981). The source of the uranium is thought to be similarities and may be coeval, although no dating hasbeen Sloko Group volcanic rocks which20 lie to 30 metres above done. Possible alkalic porphyry systems peripheral to the the main showing. Uranium may have been leached from Limpoke pluton may he younger,if they are related to syeni- the Sloko Groupby migrating groundwaterand precipitated tic intrusions that cut the pluton, which has an emplacement on organic-rich material as secondary uranium minerals age of 194+2 Ma (Brown er al.. 1992~;Appendix 13). (Bell, 1981; Salat and Noakes, 1979). Early Jurassic Texas Creek suite alkalineto calcalkaline magmatism is associated with a broad spectrumof deposits CUMUUTE MAGNETITE in the Stewart-lskut belt, including porphyry copper-gold The Shakes Creek cumulate iron occurrence (MIN- (Kern), transitional veins (Premier, Sulphurets, Snip, Stone- FTLE 1046026) consists of a magnetite-rich clinopy- house) and high-sulphidation epithermal systems flreaty roxenite (Latimer Lake pluton) that intrudes Stuhini Group Glacier). The association of precious metal mineralization tuffaceous siltstone and andesite. Intercumulate and cumu- with more alkaline intrusions is well documented (Barr ef late magnetite averages 13 to 19% of the clinopyroxenite 01.. 1976). A well datedexampleis the Premiermine, where (“Intyre, 1966). The property was trenchedand drilled in Premier Porphyry dikes have been dated at194.8+2 Ma by the late 1960s.At this time a bulldozertrail was established U-Ph on zircon (Alldrick et ol., 1986). In the project area, from Gtenora on the Stikine River to the iron deposit. how-vein and skam mineralization related to the Early Jurassic ever, it has since been overgrown. magmatic event is found primarily in older rocks, suggest-

Bulletin 95 113 ~~ ~ ~ ing a lower structural level at the time of mineralization. with deposits for whichK-AI, U-Pb orhiostratigraphic dates Examples include the Scud River area, where veins in Pa- are available. Resolution of the Pb-Pb data does not dis- leozoic sequences may be genetically related to the Early criminate between Early and Middle Jurassic, or Jurassic Jurassic Pereleshin pluton. Younger, Early Jurassic miner- and Late Triassic events,hut does provide gooddiscrimina- alizationrelatedtoplutonsoftheConeMountainsuite(187- tion between Triassic-Jurassic and Tertiary events. Galena 180 Ma) issuggested bythe proximity of polymetallic vein from five showings in the project area can be comparedwith systems tothe Strata Glacier pluton. the Ph-Pb fingerprints developed for the Stewart-Iskut belt (Figure 5-3;Appendix 15). EARLY TO MIDDLE JURASSIC: Lead from the Plum and Player transitional veins falls VOLCANOGENIC MASSIVE SULPHIDE within the Jurassic cluster, consistent with genetica link to DEPOSITS the nearby Strata Glacier pluton, which is part of the Early Early to Middle Jurassic metallogenyof the Iskut camp Jurassic Cone Mountain suite.Vuggy quartz-sulphide (epi- also includes volcanogenic massive sulphide deposits,with thermal?) vein float sampledin Deeker Creek (sample 113) Eskay Creek being the outstanding example. Farther south,within the Eocene Sawback pluton, falls withinthe Tertiary in the Hazelton Group of the Alice Arm area, silver-rich cluster, consistent with its geologic setting. Lead signatures lead-zinc-barite deposits of the Dolly Varden camp have from two other showingsare more problematic.The Forgot- also been interpreted as Early Jurassic volcanogenic exten showing, another transitionalvein, is immediately east halites (Devlin and Godwin, 1986). Analogous mineraliza- of the Strata Mountain plutonbut plots in the Tertiary clus- tion has not been discovered in the Stikine project area, ter, suggesting that an unmapped Tertiary intrusionmay be reflecting the relatively limited exposure of the Hazelton the heat source for this system. The Devils Elbow skarn Group. showing is spatially associatedwith the Devils Elbowplu- MIDDLE JURASSIC: CALCALKALINE 39.0 PORPHYRY DEPOSITS AND TRANSITIONAL VEINS Secondary biotite from Schaft Creek yieldeda 1856 38.8 Ma K-Ar age (Panteleyevand Dudas, 1973), which overlaps the range of K-AI dates for Galore Creek; in addition, the 9 error is in the rangeof dates for the MiddleJurassic Yehiniko % 38.6 0 pluton. The significance of this date is therefore unclear. N D. Although the Middle Jurassic Three Sisters suite is not re- a a gionally known for significant associatedmineral deposits, 0 synmineral felsic dikes at Schaft Creek may be related to - 38.4 the Yehiniko pluton.Other possible Middle Jurassicexam- ples in the projectareainclude prospects alongthe Yehiniko fault zone, and vein systems close tothe Conover pluton. 38.2 EOCENE: EPITHERMAL TO TRANSITIONAL VEINS, PORPHYRY MOLYBDENUM-COPPER 15.i 'TERTIARY' D a 'JURASSIC' DEPOSITS w CLUSTER 0 Epithermal gold mineralizationis known in the Eocene N .D Skukum Group volcanics thein southern Yukon; correlative P r- 0 Devils Sloko Group volcanics extend as far south as Mount N Helvekerintheprojectar~.ExtensiveEocenedikeswarms, Elbow intrudingJurassic and olderrocks south of Strata Creek,sug- 15.E gest that the higher level manifestationsof Eocene mineralization have been eroded in the project area. Within this north-trending belt, tungsten-bearing polymetallic transitional vein mineralization has been interpreted to be related to Eocene magmatism. The style of mineralization reflects 15.i5 1 a deeper, suhvolcanic structurallevel. Porphyry-style mo- 18. 5 18.719.1 18.9 19.3 19.5 lybdenum-copper-silver showings at the Ben prospect are further evidenceof Eocene mineralization. 206PbJ204Pb Figure 5-3. Five new galena lead isotope signatures for mineral GALENA-LEAD ISOTOPE RESULTS showings in the project area (solid black symbols)relative to the twoclustenofGodwineral.(1991)thatwerederivedfordeposits Galena-lead isotope data from the Stewart-lskut area in the Stewan - lskut area. Includes datefor Devils Elbow from define two main clusters which loosely fingerprint Jurassic I.C.L. Webster (personal communication, 1990) and McLymont and Tertiary ages of mineralization (Godwin et al., 1991). Creck data from AD. Ettlinger (pemonal communication, 1991). Interpretation of Pb-Pb cluster ages basedis on comparison

114 Geological Survey Brmch ton, believed to he MiddleJurassic in age. Its lead signature Resources' Banington River placeroperation had intermit- also plots in theTertiary cluster, suggesting either that min- tent production during this time (no production statisticsare eralization isgenetically related to the EoceneSawback Plu- available). ton, which crops out a kilometre to the west, or that the Devils Elbow pluton is younger than presently interpreted. MINERAL POTENTIAL EXPLORATION ACTIVITY During the mapping project 133 grab samples were collected to characterize mineral occurrences. They were ana- Exploration focused on porphyry deposits in the 1960s lysed for precious and base metals and pathfinder elements and 1970s. This resulted in widespread activity centred on (Appendix 14). Mineral potential is varied but remains in- tbe Galore Creek and Schaft Creekdiscoveries. Following completely tested hecause the area is remote and rugged a lull from the late1970s until the mid-I980s, gold-related (Table 5-2). Several areasof regional geochemical anoma- exploration activity increased dramatically. Spurred by the lies and newly discovered small showings warrant further July 1987 release of Regional Geochemical Survey data and exploration and evaluation. Contact zonesaround Limpoke exploration successesin the Stewart-Iskut and Toodo,,-*one pluton remain exploration targets with silicified and pyri- camps, companies returned to the Telegraph Creek map tized float and placer gold known nearby. The syenite dike area.Theamountofunstakedgroundintheregioncompared swarm and associated limonitic alteration zones hold poten- with almost complete claim coveragein the "Golden Trian- tial for porphyry mineralization. Prominent rusty, pyritic al- gle" to the south also provided opportunities. teration mnes north of Devils Elbow Mountain couldhost Preliminary property work and regional prospecting copper-goldskarns. Local areasofStuhini Groupsubmarine were completed by Cominco Exploration Limited, felsic volcanic rocks are a favourable setting for massive Homestake Mineral Development Company, Equity Engi- sulphide deposits. Early Jurassic alkaline plutons and sub- neering Limited, Coast Mountain Geological Services Lim- volcanic intrusions remain prime targets for gold explora- ited. Hi-Tec Ltd. and Teck Corporation. Integrated tion.

TABLE 5-2 SUMMARY OF DEPOSIT TYPES AND MINERAL POTENTIAL SElTlNGS IN THE PROJECTAREA

Model NorthernExamples B.C. PotentialArea With

Calcalkaline porphyry copper- Schaft Creek, Early-Middle Jurassic calcalkaline intrusions molybdenum Red Chris and peripheral volcanic sequences

Alkaline porphyry copper-gold Galore Creek Early Jurassic K-feldspar megaclystic Kern porphyry intrusions

Porphyry molybdenum-silver Alice Arm, Adanac Eocene intrusions

TransitionaVmesothermal veins (Au Snip, Premier, Johnny Early Jurassic K-feldspar megacrystic iAg, C&Zn, Pb) Mountain, Golden Bear intrusions, shear wnes

Epitbed veins (A% Ag) Mount Skukum, Sloko Group, Hazelton Group Toodoggone, Premier(?), Treaty Glacier

Volcanogenic massive sulphide: Tulsequah Chief Devonian-Permian Stikine assemblage Kumko-type Eskay Creek Hazelton Group (Mount Dilworth and Salmon (C& Zn, Pb, Au, Ag) River formations) Sh McLymont Creek Widespread (mixed carbonate-volcanic (Au, Cu, Zn-Pb,W) sequences inwded by plutons) Strutabound uranium Sustut Group

Coal Tuya River coalfield Sustut Group

Placer gold Barrington River, Barrington River Dease Lake,Cassia Brirish Columbia

116 Geological Survey Branch Minisrw of Employment ami Invesrmcnr

CHAPTER 6 SIJJMMARY AND CONCLUSIONS

The following conclusionsstem fromthe four field sea- semblage, with no exposed base, is divided into Upper Car- sons ofmapping in the western Telegraph Creek map area. boniferous tholeiitic volcanicrocks and sedimentary rocks The general stratigraphic sequence,intrusive episodes and both containing discontinuous limestone intervals (Devils defomational events areillustrated on Figure 6-1. The map Elbow and Butterflyunits), Upper Carboniferousto Lower area is underlain by Carboniferous to Permian Stikine as- Permian felsic tuff (Navo formation), thick Permian lirne- semblage strata unconformably overlainby unnamed Lower stone (Ambition Formation)and tuff, wacke and chert (Scud and Middle Triassic sedimentaryrocks in isolated localities Glacier formation). The deposition of Early Permian lirne- and by extensive Upper Triassic volcanic rocks of the stone worldwide has no strictly valid modem analogues be- Stuhini Group. Lower Jurassic volcanic rocks correlated cause many Paleozoic reef builders are now extinct with the Hazelton Group lie unconformably on the Stuhini (Kennett, 1982). These shallow-water carbonate accumula- Group in one area. They, in turn, are overlain unconfor- lions, like the Ambition Formation, were very important in mably by Upper Cretaceous to Paleocene polymictic con- the global carbonate budget before100 Ma, before deep-sea glomerate tentatively included in the Sustut Group. Eocene carbonate-secreting organisms (planktonic foraminifera and pyroclastic volcanic rocks andassociated sillslflows cap the calcareous nannoplankton) developed (ibid). The thick ac- succession. Five newU-Pb and six new K-Ardates, together cumulation of open-marine limestone suggestsa relatively with numerous macro and microfossil age determinations, stable tectonic setting for at least30 Ma. The low-diversity help refine the stratigraphic successions. fauna was dominated by benthic organisms. By the Upper Paleozoic rocks of the Stikine assemblage span about Permian, interbedded tuff, representing local calcalkaline 65 Ma inthe study area, older Devonian strata, as found in pyroclastic volcanism, and chert and argillite were depos- Ithe Forrest Kerr Creek area, areunrecognized here. The as- ited.

ISOTOPIC DATES INTRUSIVE DEFORMATION MINERALIZIN( STRATA PLUTONS STRATA EVENTS SUITES EVENTS i I I I I I

Sksena told belt

King Salmon la"l1

Folding

Tahcaninn 0rODe"y

I -! Figure 6-1. Summary of stratiglaphic, intrusive, structural and mineralizing eventsfor wesiem Telegraph Creek maparea. Isotopic data from Holbek (1988) and While et al. (1968) is included. ~

Lower and Middle Triassic siltstone, argilliteand im- which are coeval and probably comagmatic with Stuhini pure limestone occurisolated as and rare exposuresbetween Group volcanism. Late Triassic to Early Jurassic alkaline the Stikine assemblage and Upper Triassic Stuhini Group. plutons (Copper Mountain suite) have ultramafic and The Upper Triassic (Stuhini Group) records the estab- syenite phases and include the Rugged Mountain plutonand lishment of extensive submarine arc volcanism with local Buttertly pluton in the study area and the Galore Creekin- subaerial conditions and reworking of material by fluvial trusions with associated Cu-Au mineralization immediately processes. Coarse breccias indicate significantrelief and the to the south.The Early Jurassic event, genetically relatedto diverse clastcompositions suggestunroofing of the plutons vein deposits in the Stewart-Iskut area,comprises theTexas (e.g. Hickman pluton) synchronouswith erosion of the Tri- Creek suite with large. calcalkaline heteorgeneous plutons assic volcanic pile and some of the Paleozoic strata. The (e.g. Limpoke pluton). A new, late Early Jurassic intrusive composition of the flowsvaries from tholeiiticto calcalka- suite hasbeen proposed based on data forthe Cone Moun- line. Some of the volcanic rocks have shoshonitic affinity tain pluton; these plutons arecoeval with part of the Hazel- and they commonly contain large augite phenocrysts. The ton Group volcanism. Middle Jurassic plutons (Three group is divided into several sedimentary and volcanic- Sisters suite) includes theYehiniko pluton that is bordered dominated facies with Carnian and Norian fossil ages. By on the north and south by Late Triassic plutons.The lack of the late Norian there wasa lull in volcanism and a marine Cretaceous plutonsand volcanic rocks in the area reflects a transgression. prominent magmatic hiatus. Muchof the western part of the map areais underlain by Eocene plutonsof the Hyder suite, An angularunconformity betweenupperTriassicstrata with extrusive equivalents representedby the Group. and Lower to Middle Jurassic Hazelton Group rocksis lo- Sloko The chemistry of the plutons shows atemporal progression cally apparent. Folded Norian siltstone and argillite are from metaluminous, low-silicaquartzdiroite togranodiorite overlain by subhorizontalToarcian or olderflows in an ex- in the Late Triassic to more evolved peraluminous granite posure west of Yehiniko Lake. Interfingering marine and by the Middle Jurassic and Eocene. subaerial volcanic rocks comprise this Hazelton Group outlier. Buff-Weathering limy wackeswith ammonites, belemnites and Weyla fragments illustrate shallow-marine STRUCTURE conditions for partof the succession. Nearby, subaerialma- roon-weathering hornblende-plagioclase-phyric flow- The study area lies between three regionally extensive banded dacite and andesite are Toarcian or older. These fault systems: King Salmon fault(100 km north), Sumdum- strata are overlain by submarine amygdaloidal basalt (pos- Fanshaw fault(75 km southwest), and Skeenafoldbelt (125 sibly Bajocian) with interpillow carbonate. km east). In this area, four episodesof deformation are de- tined pre-Late Triassic contraction(Dl), and structural cul- Middle to Upper Jurassic Bowser Lake Groupand Cre- mination development (D2, Tahltanian orogeny); post-Late taceous Skeena Group and lower Sustut GroupcharacterizeTriassic to pre-Toarcian contraction03); and Middle Juras- the northeastern Skeena fold belt, but are absentin the study sic to Cretaceous contraction(D4). The earliest episode was area, either due to nondepsition or erosion. Upper Creta- synmetamorphic and produced chlorite-sencite foliation ceous toPaleocenealluvial fandepositsoftheBrothers Peak (SI) and rare isoclinal folds(FI) in Carboniferous rocks. SI Formation (Sustut Group) lie unconformablyon the Hazel- was folded during D2 into open to tight chevron style folds ton and Stuhini Groups.The polymictic fanglomeratesmark (F2). Evidence forthetiming ofD2remainsequivocal. Open a major erosional event, probably related to uplift of the folds, overturned beddingand reverse faults, possibly north- Coast Belt. The braided alluvial fans also had local boggy east directed, developed during D3, and the younger age sections where coal seams developed.In addition, episodic limit is an angular unconformity at the base ofthe Lower pyroclastic volcanism blanketed thearea with felsicash tuff. Jurassic Hazelton Group.D4 produced crenulationsin phyl- Eocene magmatism is representedby an isolated outlier of litic Carboniferous strata, tight folds in Permian limestone Sloko Group continental arc volcanic rocks,and large coe- and mylonitic foliations of a late Early Jurassic Cone Moun- val batholiths that form muchof the Coast Beltat this lati- tain pluton. The paucity of Jurassic or younger strata pre- tude. Flat-lying basalt flows near Latimer Lake are vents unequivocal assignment of features to specific correlated with Neogene volcanic rocks from either the deformational episodes. Mount EdzizaComplexto theeast or LevelMountain shield volcano to the north. The contrast in structural trends of Paleozoic and Tri- assic strata is noteworthy. North of the Stikine River, folds and faults trend northeast and east, but to the south, they PLUTONISM trend north and northwest. The orientations of Permian Seven new U-Pb and fourteen newK-Ar age determi- limestone massifs delineatethese trends most clearly. They nations help define eight plutonic suites emplacedduring are partially controlled by contraction faults (e.& Cone six episodes: Middle toLate Triassic,Late Triassic to Early Mountain and Jimjack faults). The bend from northwestto Jurassic, Early Jurassic, a new late Early Jurassic, Middle east-trending southwestof the Chutine River remains enig- Jurassic and Eocene plutonic suites. Two groupsof Middle matic, partly because the closure is intruded by an Eocene to Late Triassic plutons are defined: small, isolated Alas- pluton. Four structural culminations (Little Tahltan Lake, kan-type ultramafic bodies (Mount Hickman Ultramafic Barrington River,ChutineRiver andMissisjay Creek)cored Complex and two smaller bodies)and much larger Stikine by Paleozoic strata display more penetrative fabrics than suite calcalkaline plutons(e.g. Hickman batholith), both of surrounding Mesozoic rocks.

118 Geological Survey Brmh In addition, several fault systems are described, Environments favourable for Kuroko-type massivesul- including the Cone Mountainand Scud Glacier faults.The phide deposition existed duringthe Devonian, Carhnifer- Cone Mountain fault and related structures are part of a ous and Middle Jurassic, when submarine arc volcanism major southwest-verging compressional event post-late was prevelant. Parts ofthe Stikine and Hazelton Group have Early Jurassic. North, northeast, northwest and massive sulphide potential, especially where rhyolitic vol- east-trending faults are also common. canic rocks are deposited on more mafic flows andtuffs. More evolved, precious metal bearing, silicic porphyry METAMORPHISM deposits and epithermal veins are associated with Eocene Most rocks in the map area display greenschist grade continental volcanism (Sloko Group)and plutonism (Hyder mineral assemblages, including quartz, albite, carbonate, suite). chlorite, epidote, clay mineralsand pyrite. Primary textures are commonly preservedin most Mesozoic rocks, it isonly LATE TRIASSIC -- STUHlNl ARC 1 in the Paleozoic strata that Penetrative deformation has ob- oceanicisland arc scured original features. These penetrative fabrics developed during the firstof two thermal events, a Permo-Triassic metamorphic event ("Tahltanian orogeny"). The second, a Middle Jurassic event, is postulated from partially resetK- Ar dates and coincides with emplacementof the Three Sis- ters Plutonic Suite.

ECONOMIC GEOLOGY The map arealies within an important metallogenicbelt encompassing active mines and past producers between Ste- .- wart and Tulsequah. British Columbia.The potential for un- EARLY JURASSIC -- HAZELTON ARC discovered mineral occurrences remains very high but I arcisland oceanic potential for economic deposits is probably moderate; exploration targets include: porphyry deposits in Mesozoic and Cenozoic rocks (e.g. Galore Creek, Schaft Creek and Ben showing); volcanogenic massive sulphides in the De- vonian and Carboniferous part of the Stikine assemblage (e.g. Tulsequah Chief) and Jurassic Hazelton Group (e.& Eskay Creek); shear-hosted gold (e.g. Snip mine along the Iskut River); fault-controlled mesothermalgold (e.g. Gold- en Bear mine); precious metal veins (e.g. Premier. Sul- phurets, Skukum mine). MIDDLE JURASSIC Alkalineandcalcalkalineporphyrycopperdepositsand veins developed where plutons intruded active oceanic arcs continental margin arc S (duringthe Late Triassic (Stuhini Group)and Early to Middle .Jurassic (Hazelton Group). Stuhini Group volcanic rocks :and coeval subvolcanic intrusive rocks host the Galore i tCreek copper-gold and Schaft Creek copper-molybdenum 4 porphyry deposits, and remain unexploited resources; im- proved infrastructure would facilitate their development. -1 Eocene calcalkaline porphyry molybdenum systems are also known, for example,the Ben occurrence lies alongthe eastern flank of the Coast Plutonic Complex. These hydrothermal systems have potential for hosting high-grade dver veins as exploitedsouth of Stewart. Vein deposits are commonin the Lower Jurassic Hazel- J ton Group in the Stewart-Iskut area. The Hazelton outlier I near Yehiniko Lake therefore holds potential for additional occurrences. Shear-hosted veins like the Snip deposit are small targets but the spatial (and perhaps genetic?) link to t;he Red Bluff potassium feldspar megacrystic porphyrypro- vides a guide to exploration. The Rugged Mountain and 1 L.impoke pluton areas have similar porphyriesand volcano- sxlknentary hostrocks and these areas remain prospective Figure 6-2. Schematic Mesozoic tectonic evolutionof the fi~rgold-bearing veins. project area. British Columbia

(b) TECTONIC EOCENE FRAMEWORK

Late Cretaceous to Paleocene tonaiite Study area Shear Zone

Siikinia

~ ~~ ~

(a) CRETACEOUSMID-LATETECTONIC FRAMEWORK

Study area Ornineca Rocky Mountaln Skeena SustutSkeena Belt Fold and ThrustBeit Fold Bell Basm

base of lithosphere

Figure 6-3. Schematic (a) Cretaceous and @) Eocene tectonic frameworkfor northern Cordillera with the general position of the shldy area illustrated (Modified from Evenchick, 1991c: McClellandet ai., 1991; Hollister, 1992).

TECTONIC MODEL ments to the Skeena fold belt(Evenchick, 1991b. c). Ductile The Mesozoic tectonic evolutionof the region is sum- deformation along the Sumdum and Fanshaw fault systems marized in Figure 6-2. The Stuhini arc accumulated on a may represent the undelthrusting of Alexanader Terrane be- "basement" of Carboniferous and Permian strata of the neath Yukon-Tanana and Taku terranes (McClellandet d., Stikine assemblage, duringsubduction of the Cache Creek 1991). At this time, the study area lay in the less deformed oceanic crust. TheEarly Jurassic Hazelton arc formed in a hinterland, between two thrust systems of opposite ver- similar manner and overlapped the Triassicarc. By the Mid- gence, the Sumdum-Fanshaw and Skeena fold belt (Figure dle Jurassic the ctusthad thickened sufficientlyto generate 6-3a). By the Late Cretaceous to Paleocenethe Coast Range granite plutons (Three Sisters suite) and finally the Cache megalineament (Le Conte shear zone) developedwest of the Creek ocean closed and obducted ontoStikinia. The Creta- study area; it can be traced over 800 kilometres along the ceous record is poorly represented in the map area but is west margin of the Coast Belt. The Tertiary saw renewed shown diagrammaticallyin Figure 6-3. Amalgmation of the subduction to produce an extensive magmatic episode,the Alexander Terrane and Wrangellia to the North American Hyder plutonic suite and extrusive equivalents, the Sloko margin in the Cretaceous may link through basal dtcolle- Group (Figures 6-2 and 6-3).

I20 Geological Survey Bmnch Ministry of Employment and Investment

REFERENCES

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Plutonic, and Smctural Framework for the Iskut River Map Area, Northwestern Bell,R.T.(1981):PreliminaryEvaluationofUraniuminSustutand British Columbia, in Current Research, Pan E, Geological Bowser Succcssor Basins, British Columbia;in Current Re- Survey ofC&, Paper 89-IE. pages 145.154. search, Part A, Geological SurveyofCanada, Paper SI-IA, pages 241-246. Anderson (1993): A Mesozoic Stratigraphic and PlutonicFrame- work for Northwestem Stikinia (Iskut River Area), North- Berger, W.H. (1974): Deepsea Sedimentation; in The Geology of western British Columbia, Canada; in Dunne, G. and Continental Margins, Burke,C.A., andDrake, C.L..Editors. McDougall, K, Editors. Mesozoic Paleogeography Sympo- Springer Verhg. New York, Heidelberg, Berlin, pages213- sium Volume,SociayofEcommic PuIeonrologistsandMin- 241. eralogirrs. Pacific Section. Betmanis, A.I. 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Southeast Alaska: Geochronology and Geochem- eralogic and Major and TraccElement Characteristics;Jour- istry; Geological Society ofAmerica, Programs with Ab- MI of Geophysical Research. Volume 94, pages 4469496. slracts, page 529. Bradford, J.A. and Brown, D.A.(1993a): Geology of the Bearskin Aspinall,N.C.(1991):AssessmentReportontheDrillingProgram and Tatsamenie Lakes Area, Northwestern British Columbia (IMWI in 1992, Grant, on the Poker Property; B.C. Minktry of Energy, Mines and and 8s); Geological Fieldwork B. Petmieum Resources, Assessment Report21,532. and Newell. I.M., Editors, B.C. Ministry ofhergy, Mines and Petroleum Resources, Paper 1993-1,pages Aspinall, N.C.,Strain, D.M. and Blain, A. (1990): Assessment Re- 159-176. port on Geological Mapping, Geochemical Sampling,Geo- Bradford, J.A. and Brown, D.A. (1993b): Geology, Mineral Oc- physical Surveying and Prospecting on the Poker Property; currences and Geochemistryof the Bearskin and Tatsamenie Lakes Areas, Northwestem British Columbia(NTS IMW1

Bulletin 95 I21 British Columbia

and 8s); B.C. Ministry of €new, Mines and PetroleumRe- and Newell, I.M., Editors, B.C. Ministry of€nergy, Mines sources, Open File 1993-1.3 sheets. andPetmleum Resources, Paper 1992-1, pages 179-195. Brew, D.A. (1988): Latest Mesozoic and Cenozoic Igneous RocksBrown, D.A..Neill, L,T~mmerman,J.,Harvey-Kelly,F.,Gunning, of Southeast Alaska - A Synopsis; US.Geological Survey, M.G. and Greig, C.J. (1992b): Geology, Mineral Occur- Open-File Report 88-845. rencesandGeochemisttyoftheTahltanLake-ChutineRiver Brew, D.A.. Ovenshine, A.T., Karl, S.M. and Hunt, S.1. (1984): Area,NorthwesternBritishColumbia(104G/12W,13);B.C. Preliminary Reconnaissance Geologic Map of the Peters- Ministry of €nergy, Mines and Petroleum Resources, open burg and partsof the Port Alexander and Sumdum1:25O,ooO File 1992-2. Quadrangles, Southeastern Alaska;U.S. GeologicolSurvey, Brown, D.A., Greig, C.I., Bevier, M.L. and McClelland, W.C. Open-File Report84405.43 pages. (1992c):U-PbZirconAgesfortheHazeltonGroupandCone Bridge, D.A., Marr, J.A., Hashimoto, K., Obara,M. and Suzuki, Mountain and Lirnpoke Plutons, Telegraph CreekMapArea, R. (1986): Geologyof the Kutcho Creek Volcanogenic Mas- Northwestern British Columbia: Age Constraintson Volcan- sive Sulphide Deposis Northern British Columbia; Cana- ism and Deformation;in Radiogenic Age and Isotopic Stud- dim Institute ofMining and Mefollurgy, Special Volume 37, ies: Report 6; Geologicol Survey of Canada, Paper 92-2, pages 115-128. pages 153-162. Brown, D.A. (1987): Geological Selling of the Volcanic-hosted Btown,G.C.,Thorpe.R.S.andWebb,P.C.(1984):~eGeochemi- Silbak Premier Mine, Northwestern British Columbia;un- cal Characteristics of Granitoids in Contrasting Arcs and published M.Sc. thesis, The University ofBritish Columbia, Comments on Magma Sources; Journal of the Geological 216 pages. Society of London, Volume 141, pages 413-426. Bud- dington, A.F. (1929): Geologyof Hyder and Vicinity,South- Brown, D.A. (1993): Geology of the Tahltan Lake Area, North- eastern Alaska; U.S. Geological Survey, Bulletin 807. 124 western British Columbia (104G/13);B.C. Ministry of En- pages. ergy, Mines and Petroleum Resources, Geoscience Map 1993-6. Cannichael, R.G. and Holbek, P.M. (1989): 1989Prospecting Re- port on the Rugged Mountain Property Canyon 25 Claim, Brown, D.A. and Greig, C.J. (1990): Geology of the Stikine River B.C. Ministry of €new, Mines and Petroleum Resources, - Yehiniko Lake Area. Northwestern British Columbia Assessment Report 19,072. (104G/llW, 12E);inGeologicalFieldwork 1989,B.C.Min- istry of Energy, Mines and Petroleum Resources, Paper Carer, E.S., Orchard, M.J., Ross, C.A., Ross, J.R.P., Smith, P.L. 1990.1, pages 141-151. andTipper,H.W. (1991): PartB,PaleontologicalSigna~~es of Terranes;in Chapter 2 of Geology ofthe CordilleranOro- Brown, D.A. and Gunning, M.H. (1989a): Geology of the Scud gen in Canada, Gabrielse,H., and Yorath. C.J., Editors,Geo- in River Area, Northwestern British Columbia (1046/5,6); logical Survey of Conada, Geology of Canada, No. 4, pages Geological Fieldwork 1988,B.C. Ministry of €nergy, Mines 28-38. andPetmleum Resources, Paper 1989-1, pages 251-267. Chappell,B.W.andWhite,A.J.R.(1974):TwoContrastingGranite Brown,D.A.andGunning,M.H.(1989b):GeologyandGeochem- Types; Pacific Geology, Volume 8, pages 173-174. ishy of the Scud RiverArea, Northwestern British Columbia (104G/5,6); B.C. Ministry of€nergy, Mines and Petroleum Chung,P.L.(1990a):GeochemicalReportontheOksaCreekProp Resources, Open Fkle 1989-7. erty; B.C. Ministry of Energy. Mines and Petroleum Re- sources, Assessment Report 19,876. Brown, D.A. and Gunning, M.H. (1993a): Geology of the Scud River Area, Northwestern British Columbia (104G15);B.C. Chung, P.L. (1990b): GeochemicalReport on the WKProperty; Ministry of€nerg% Mines and Petroleum Resources, Geos- B.C. Ministry of €new, Mines ond Petroleum Resources, cience Map 1993-3. Assessment Report 19,892. Brown, D.A. and Gunning, M.H. (1993b): Geology of the Scud Chung, P.L. (199oC): Prospecting Report on the Snow Property; Glacier Area, Northwestern British Columbia (104G/6); B.C. Ministry of €nergy, Mines and Petroleum Resources, B.C. Ministry of Energy, Mines and Petroleum Resources, Assessment Report 20,002. Geoscience Map19934. Cordey, F. (1992): Report on Radiolarians andother Microfossils; Brown. D.A.,Greig, C.J.andGunning,M.H. (1990): Geology and Geological Survey ofCanada, Report number FC-1992-2 Geochemistty of the Stikine River - Yehiniko Lake ha, Cox, D.P. and Singer, D.A., Editors (1986): Mineral Deposit Mod- Northwestern British Columbia (104G/llW, 12E); B.C. els; United States Geologicol Survey, Bulletin 1693, 379 Ministry of Energ% Mines and Petroleum Resources, Open pages. File 1990-1. Currie, L.D. (1992): MetamorphicRocks in the Tagisb LakeArea, Brown, D.A., Greig, C.J.and Gunning, M.H. (1993): Geology of Northern Coast Mountains, British Columbia: A Possible the Yehiniko Lake and Chutine River Area, Northwestern Link between Stikinia and parts of the Yukon-Tanana Ter- BritishColumbia(104G/llW, 12);B.C. MinistryofEnergy, rane, in Current Research, PartA, Geologicol Survey of Con- Mines MdPetroleum Resources, Geoscience Map 1993-5. ada, Paper 92-1A, pages 199-208. Brown, D.A., Logan, 1.M.. Gunning, M.H., Orchard, M.1.and Davis,J.W.(1988):GeologicalandGeochemicalReportontheMJ Bamber, W.E. (1991): Stratigraphic Evolutionof the Paleo- 1 to 16 Claims, Stikine RiverArea;B.C.Ministryof€nergy, zoic Stikine Assemblage in the Stikine and lskut Rivers Mines and Petroleum Resources, Assessment Report Area, Northwestern British Columbia;Canodian Journal of 18,134. Eonh Sciences, Volume 28, pages 958-972. Dawson, G.M.(I 889): Reporton an Exploration inthe Yukon Dis- Brown, D.A., Harvey-Kelly, F.E.L., Neill, I. and T1mmerman. 1. trict, N.W.T. and adjacent northern portionof British Colum- (1992a): Geology of the Chutine River- Tahltan Lake Area bia; Geological ond Natural History Survey of Canada, (104G/l2W, 13); in Geological Fieldwork 1991, Grant, B. Annual Report 1887-88, Volume111, Part B, 7B.

I22 Geologicol Survey Branch Ministn, of Employmenr and Inveshncnt

Dawson, K.M., Panteleyev. A., Sutherland Brown. A. and Evenchick, C.A. (1991~):Geometry, Evolution, and Tectonic Woodsworth, G.J. (1991): Regional Metallogeny; Chapter Framework of the Skeena Fold Belt North Central British 19, in Geology of the Canadian Orogen in Canada, Columbia; Tectonics. Volume IO, pages 527-546. Gabrielse, H. and Yorath, C.J., Editors, Geological Survey Fladmark, K.R. (1985): Glass and Ice. The Archaeology of Mt of Canada, Geology of Canada, No.4, pages 707-768. Fdzim Deporrmenr of Archaeology, Simon Fraser Univer- Deer, W.A.,Howie, R.A. andzussman, J. (1977): Anlnlroduction sity, Publication 14,217 pages. to the Rock-forming Minerals;Longmnn, 528 pages. Folk,P.(1981a):GeochemicalReponontheLimp#2Claim;B.C. de Rosen Spence. A. (1985): Shoshonites and Associated Rocks MinisfryofEnergy,MinesandPetroleumResources, Assess- of CenmlBritish Columbia; ln Geological Fieldwork1984, ment Report9092. B.C. Ministry of Enem, Mines and Petmleum Resources, Folk, P.G. (1981b): Report on the Geology, Trenching and Sam- Paper 1985-1,pages 426442. pling of the Marg and Dok Claims; in Assessment Report Devlin, B.D. and Godwin, C.I.(1986): Geology of the Dolly Var- 9617. den Camp, Alice Arm Area (103Plll. 12); in Geological Fox, P.E., Grove, E.W., Seraphim, R.H., Sutherland Brown, A. Fieldwork 1985, B.C. Ministry of Enem, Mines and Petro- (1976): Schaft Creek;in Porphyry Deposiuof the Canadian lewn Resources. Paper 1986-1, pages 327-330. Cordillera, Sutherland Brown, A., Editor,Canadian Instirute Dirom, G.A. (1964): Reliminary Geological Reporton Conover of Mining and Metallurgy, Special Volume 15, pages 219- Creek Group;B.C. Ministry of Enem, MinesandPermleum 226. Resources, Assessment Report591. Frith, R.A. and Fryer, B.J.(1985): Geochemistry and Origin theof Drobe,J.R.,Logan,J.M.andMcClelland,W.C.(1992):EarlyCar- Regan Intrusive Suite and other Granitoids in the North- boniferous Plutonism in Stikinia, Stikine and Iskut Rivers eastern Slave Province, Northwest Canadian Shield:Cana- Area, Northwestem British Columbia; in Abstract Volume, dian Journal of Earth Sciences, Volume 22, pages Cordilleran Tcctonics Workshop, University of Edmonton, 1048-1065. Report No.24. Gabrielse, H. (1980): Dease Lake Map Area; Geological Survey Dudas, B.M. (1972): Sno, Bird (Liard Copper); in Geology, Ex- of Can&, open File 707. ploration and Mining in British Columbia,B.C. Minisrry of Gabrielse. H. (1985): Major Dextral Transcurrent Displacements Enem, Mines and Petmlewn Resources, pages 3940 along the Northern Rocky Mountain Trench and Related Dum. (I 990): Latimer Lake Project, Report on Geological. Geo- Lineaments in North-central British Columbia; Geological chemical and GeophysicalPrograms on the Dole 1-4, Lake Society ofAmerica, Bulletin, Volume 96,pages 1-14. 1-4, Bake 1-4 and EN Claims; B.C. Ministry of Energy. Gabrielse, H. (1991): Late Paleozoic and Mesozoic Terrane Inter- Mines and Petroleum Resources, Assessment Report actions in North-central British Columbia;Canadian Jour- 20.523. MI of Earrh Sciences, Volume 28, No. 6, pages 947-957. Eby, G.N. (1992): chemical Subdivisionof the A-type Granitoids: Gabrielse.H.andYorath.CJ.(1991):TectonicSynthesis.Chapter Petrogenetic and Tectonic Implications; Geology, Volume 18; in Geology of the Cordilleran Orogen in Canada. 20, pages 641-644. Gabrielse, H. and Yorath, C.J., Editors, Geological Survey Eccles,L.(1981):GeologicalandGeochemicalReportontheMist of Cad,Geology of Canada. No. 4, pages 677-705. 1 and 2 Claims; B.C. Ministry of Enem, Mines and Perm- Gabrielse, H., Monger, J.W.H., Templeman-Kluit, D.J., and lewn Resources, Assessment Report9218. Woodsworth, G.J. (1991a): Structural styles, Part C. Inter- Eisbacber, G.H.(1974): Sedimentary History and Tectonic Evolu- montane Belt; in Chapter 17 of Geology of the Cordilleran tion of the Sustut and Sifton Basins, North-central British Orogen in Canada, Gabrielse, H. and Yorath, C.J., Editors, Columbia; Geological Survey of Canada, Paper 73-31.57 Geological Survey of Canada, Geology of Canada, No. 4, pages. pages 591-603. Engerbnmn, D.C.,Cox, A. and Gorden. P.C. (1985): Relative Gabrielse, H., Souther. J.G., Woodsworth, GI., lipper, H.W. and Plate Motions Between Oceanic and Continental Plates in Monger, J.W.H. (1991~):The Intermontane Belt in Chapter the Pacific;Geological Association ofAmerica. Special Pa- 9,Geology of the CordilleranOrogen in Canada, Gabrielse, per 206.59 pages. H. and Yorath, C.J., Editors, Geological Survey of Canada, Epstein, A.G.. Eptsein, J.B. and Harris, L.D. (1977): Conodont Geology of Canada, No.4, pages 345-351. Color Alteration- an Index to Organic Metamorphism:U.S. Gabrielse. H., Monger, J.W.H.. Wheeler, 1.0. and Yorath, C.J. Geological Survey Rofessional Paper 995.27 pages. (1991b): Morphogeological Belts, Tectonic Assemblages Evenchick, C.(1986): Structural Styleof the Northeast Marginof and Terranes, in Chapter 2 of Geology of the Cordilleran the Bowser Basin, Spatsizi Map Area, North-central British Orogen in Canada, Gabrielse, H. and Yorath, C.J., Editors, Columbia; in Current Research,Parr B, Geological Survey Geological Survey of Cad,Geology of Canada, No, 4, of Canada, Paper 86-1B, pages733-739. pages 15-28. Evenchick, C.A. (1991a): Jurassic Stratigraphy ofEast Telegraph Gale, R.E.(1964): Geological Reportof Mineral Claims BIK 137 Creek and West Spatsizi Map Areas, British Columbia: in to BIK 160. B.C. Ministry of .Energy, Mines and Petroleum Cumnt Research, PartE GeologicalSurvey of Canada, Pa- Resources, Assessment Report592. per 91-1E,pages 155-162. Geological Survey of Canada (1957): Operation Stikjne, Map 9- Evenchick, C.A. (1991b): Smctural Relationships of the Skeena 1957. Fold Belt Westof the Bowser Basin, Northwest BritishCo- Gill, J. and Whelan,P. (1989): Early Rifting of an Oceanic Island lumbia; Canadian Journal of Eorrh Sciences, Volume 28, Arc (Fiji) Produced Shoshoniticto Tholeiitic Basalts;Jour- pages 973-983. mlof Geophysical Research, Volume 94,pages4561-4578.

- Bulletin 95 123 Godwin, C.I., Pickering, A.D.R. and Gabites, J.E. (1991): Inter- Harland, W.B., Armswong, R.L., Cox, A.V.. Craig, L.E., Smith, pretation of Galma Lead Isotopes from the Stewart Area A.G. and Smith, D.G. (1990): A Geological TieScale (1030, P IMA,B,G), in Geological fieldwork 1990, B.C. 1989: Cambridge University Press, Cambridge, 263 pages. Ministry of Enem, Mines and Petmleum Resources, Paper Hart, G. and Mihalynuk,M. (1992): The Tally-Ho Shear~ Lewel- 1991-1, pages 235-243. lyn Fault Zone: Controls on Tuning and ?Lpes of Intern- Graf, C. (1985a): Chutine1.2.3 Mineral Claim (Conover Creek); tions between Nisling and Stikine Terranes in Northem B.C. Minisfry of Energy. Mines and Petroleum Resources, British Columbia and Southern Yukon Territory; Cordilleran Assessment Report 14,216. Tectonics Workshop, Universiry ofAlberta, Report No. 24, Graf, C. (19856): Kirk Mineral Claim; B.C. Ministry of Energy. page 87. Mines and Petroleum Resources, Assessment Report Hedley, M.S. (1966a): Limpoke;in LodeMetals in British Colum- 13,662. bia, B.C. Ministry of Energy, Mines and Petroleum Re- Greenwood, H.J.. Woodsworth, G.J., Read, P.B., Ghent, E.D. and sources, page 18. Evenchick, C.A. (1991): Metamorphism, Chapter16; in Ge- Hedley, M.S. (1966b) MH, in Lode Metals in British Columbia, ology of the Cordilleran Omgen in Canada, Gabrielse, H. B.C. Ministry of €new, Mines and Petroleum Resources, and Yorath, C.J., Editors,Geological Survey of Canada, Ge- page 18. ology of Canada, No. 4,pages 533-570. Henderson, J.R., Kirkham, R.V., Hendrson, M.N., Payne, J.G., Greig, CJ. and Gehrels, G.E. (1992): Latest Triassic -Earliest Ju- Wright, T.O. and Wright, R.L. (1992): Stratigraphy and rassic Orogenesis.StikineTeme, NorthwesternBritish Co- Smcture of the Snlphurets Area, British Columbia;in Cur- lumbia, Geological Sociery of America, Abstracts with rent Research, Pan A, Geological Survey of Canada, Paper Programs, Volume 24, No.5, page 28. 92-1A. pages 323-332. Grybeck, DJ., Berg, H.C. and Karl, S.M. (1984): Map and De- Hodgson,CJ.andLeBel,J.L.(1974):SouthTahlfan~eProperty scription of the Mineral Depositsin the Petersburg andEast- (# 656 A) Magnetometer Survey;B.C. Ministry of Energy. ern Port Alexander Quadrangles, Southeastern Alaska,US Mines and Pefmleum Resources, Assessment Report5097. Geological Survey Open-File Report 84-837, scale Holland, S.S. (1950): PlacerGoldProductionofBritishColumbia; 1:25O,OOO, 87 pages. B.C. Ministry of Energy, Mines and Petroleum Resaunes, Gunning, M.H. (1990): Stratigraphy of the Stikine Assemblage, Bulletin 28.89 pages. Scud River Area, Northwest British Colmbia;in Geological Holland, S.S. (1976): Landformsof British Columbia, A Physiog- Fseldwork 1989, B.C. Ministry ofEnergy, Miner ondPetm- raphic Outline; B.C.Minisfry of Energy,Mines and Perm- leumResources, Paper 1990-1, pages 153-161. leum Resources, Bulletin 48,138 pages. Gunning, M.H. (1993a):Character andEvolutionofan Uppr Car- Holbek, P.M. (1981): Geological Reporton the Late Claim;B.C. boniferous to Upper Permian Succession an in Extensional, Ministry ofEnergy, MinesandPetmleum Resources, Asseor- Oceanic Tectonic Setting; Stikine Assemblage, Northwest ment Report 9660. SLikinia, Scud River Area (NTS 104G), British Columbia, Unpublished M.Sc. thesis, University of Western Ontario. Holbek, P.M. (1988): Geology and Mineralization of the Stikine 305 pages. Assemblage, Mess Creek Area, Northwestern British Co. lumbia; unpublished M.Sc. thesis,The Univeniry of British Gunning, M.H. (1993b): Characterof Upper Paleozoic Strata and Columbia, 174 pages. Plutons,LowerForrestKerrCreekArea,NorthwesternBrit- ish Columbia;in Current Research, PartA, Geological Sur- Hunt, P.A. and Roddick, J.C. (1994): A Compilationof K-AI and vey of Canada, Paper 93-1A. pages 27-36. 40Ar-39Ar Ages: Report2; in Radiogenic Age and Isotopic SNdies; Report 8, Current Research 1994-F, Geological Gunning,M.H.,Bamber,E.W.,Brown.D.A., Rui,L.,Mamet B.L. Survey of Canada, pages 139-140. and Orchard, M.J. (1994): The Permian Ambition Formation of Northwestern Stikinia, British Columbia; in Pangea: Irving, E. and Monger, J.W.H. (1987): Preliminary Paleomagnetic Global Environments and Resources, Embry, A.F., Results from the Asitka Group, British Columbia;Canadian Beauchamp, B. and Glass, DJ., Editors, Canadian Society Journal of Earth Sciences, Volume 24,pages 1490-1497. of Petmlewn Geologists, Memoir 17, pages 589-619. 1rvine.T.N. and Baragar, W.R.A. (1971): A Guideto the Chemical Hallof, P.G. (1%3):Geophysical Surveyof the Poke Claim Group; Classification of Common VolcanicRock, Canadiun Jour- nal B.C. Ministry of Enew, Mines and Petroleum Resources, of Earth Sciences, Volume 8, pages 523-548. Assessment Report 535. Jeffery, W.G. (1967) Nabs, Paramount Mining Ltd.;in Annual Re- Hallof, P.G. (I 966): Report on the Induced Polarization and Resis- port 1966,B. C.Ministry of Energy. Mines andPetmleum Re- tivity Survey on the Gordon Claim Group;B.C. Ministry of sources, pages 29-30 Enem, Mines and Petroleum Resources, Assessment Re- Johnson, D. and Jones,P.W. (199Oa): Scud Property - 1045, Scud port 847. 10, 11, 12, 13.14 Claims; B.C. Ministry ofEnegy, Mines Hamilton, T.S. (1981): Late Cenozoic Alkaline Volcanics of the and Petroleum Resources, Assessment Report 20,184. Level Mountain Range, Northwestern British Columbia: Johnson, D. and Jones, P.W. (1990b): Scud Property- 1045, Scud Geology, Petrology and Paleomagnetism; unpublished 4,5,6,7 and 8 Claims; B.C. Ministry of Energy. Mines and Ph.D. thesis, Univeniry of Alberta, 490 pages. Permleum Resources, Assessment Report 20,185. Harayama, S. (1992): Youngest Exposed Granitoid Pluton on Johnson, D. and Jones, P.W. (199oc): Scud Property - 1045, Scud Earth: Cooling and RapidUplit? of the Pliocene-Quaternary #I, 2, 3, Alicia, Robyn Claims; B.C. Ministry of Energy, Takidani Granodiorite inthe Japan Alps, Cenml Japan, Ge- Mines and Petroleum Resources, Assessment Report ology, Volume 20, No. 7, pages 657-660. 20,186.

124 Geological Survey Branch Minisfry of Employment and lnveslmenr

Kaspef. B. (1%): Geological and Geochemical Report on the Lammle, C.A.R. (1%): Geological and Geophysical Reporton lameson 141 Claims: B.C. Ministry of Energy. Mines und Nabs 1-34 Mineral Claims;B.C. Ministry of Energy, Mines Petmleum Resources, Assessment Report 19,791. and Petmleum Resources. Assessment Report 900. Kaspzr, B. (1990b): Geological and Geochemical Report on the Lapierre, H.. Albarede, F., Albers, I, Cabanis, B and Coulon, C. Rattle and Roll Claims:B.C. Ministry of Energy, Mines and (1985): Early Devonian Volcanism in the Eastem Klamath Petroleum Resources, Assessment Report 19870. Mountains, California: Evidence for an Immature Island Keep, G. (1983): Prospecting Reporton the Lode Mineral Claims Arc, Canadian Jouml of Earth Sciences. Volume 22, pages 1-9 (inclusive) 11-12; B.C. Ministry of Energy, Mines and 214-227. Petmleum Resources, Assessment Report 11,262. Lehtinen. 1. (1989): 1989 Geologicaland Geochemical Report of Keep, M and Russell, I.K. (1989):The Geology ofthe Averill Plu- the Goat1 to 11 Claims: B. C. Ministry of Energy, Minesand tonic Complex, GrandForks, British Columbia;in Geologi- Petmleum Resources, Assessment Report 19439. cal Fieldwork 1988. B.C. Ministry of Energ): Mines and Lehtinen. J. (1990): 1989 Geological and Geochemical Reporton Petmleum Resources, Paper 1989-1, pages 27-32. the Bar 1 to 11 Claims; B. C. Ministry of Energy, Mines and Kennet (1982): Marine Geology; Prentice-Hall, Inc., 813 pages. Permleum Resources, Assessment Report 19836. Kerr, EA. (1927): Preliminary Reporton Stikine RiverArea, Brit- Le Bas, M.J. and Streckeisen, A.L.(1991): The RTGS Systematics ish Columbia;Geological Survey of Canada, Summary Re- of Igneous Rocks;Joumnl of the Geological Sociep, Lon- port 1926, Pm A, pages 14A-34A. don, Volume 148. pages 825-833. Kerr, F.A. (1929): Second Preliminary Report on Stikine River LeMaitre.R.W..Editor(1989):AClassificationofIgneousRocks Area,BritishColumbia,GeologicalSurveyofCanadn,Sum- and Glossary of Terms; BIaclovell Scientifc Publications, mary Report 1928, PartA, pages llA-26A. 193 pages. Kerr, EA. (1930): Preliminary Report on Iskut River Area, British Lewis, P.D. (1992): Structural Evolutionof the lskutRiver Area: Columbia: Geological Survey of Canado, Summary Report Preliminary Results; Mineral Deposit Research Unit, The 1929, PartA, pages 30A-61A. Universio of British Columbia, Annual Technical Report- YearZ.pages2.1-2.21. Kerr, EA. (1931): Explorationsbetween Stikine and Taku Rivers, British Columbia;Geological Survey of Canada, Summary Lewis. P.D..Thompson, J.F.H..Nadmju, G., Anderson, R.G. and Report 1930, Part A, pages 41A-55A. Johannson, G. (1993): Lower and Middle Jurassic Stratigra- phy in the Treaty Glacier Area and Geological Setting of the Kerr, EA. (1935): Stikine River Area, Cassiar District, British Co- Treaty Glacier Alteration System, Northwestern British Co- lumbia; Geological Survey of CaMda, Map 310A. lumbia: in Current Research, PartA, Geological Survey of Ken, EA. (1948a): Lower Stikine and lskut RiverAreas, British Canado, Paper 93-1A. pages 75-86. Columbia; Geological Survey of Cd,Memoir 246, 94 Lin Rui (1990): Report 23 Collectionsof Fossils from the Scud pages. on River Area: Geological Survey of Camda, Paleontology Kerr. EA. (1948b): Taku River Maparea, British Columbia:Geo- Subdivision, Calgary, report No. I-RUI-1990. logical Survey of Canado, Memoir 248.84 pages. Lin Rui (1991): Report on 1 Collection of Fossils from the Scud Kerr, P.F. (1959): Optical Mineralogy, Third Edition; McCmw- River Area, Southwestern Telegraph Creek Map Area; un- Hill Book Company, hc..442 pages. published report No, 1-RUI-1992. Korenic, 1.A. (1982a): 1981 Assessment Report of Geological, Lin Rui (1992): Report on 2 Collections of Fossils from the Tele- Geochemical and GeophysicalWork Performed on the Tuff graph Creek Area: unpublished report No. 1-RUI-1992. 1 Claim: B.C. Minisfry of Energy, MinesandPetmleum Re- Linder, H. (1975): Geology of the Schaft Creek Porphyry Copper sources, Assessment Report 10,475. Molybdenum Deposit, Northwestem B.C.; Canadian Insti- Korenic, J.A. (1982b): 1981 Assessment Report of Geological, tule of Mining and Metallurgy, Volume 68, No. 758, pages Geochemical and GeophysicalWork Performed on the Mkt 49-63. 1 and 2 Claims: B.C. Ministry of Enem, Mines and Petm- Lion, J.G. (1971): P-T Stabilities of Laumontite. Wairakite, leum Resources, Assessment Report 10,476. Lawsonite, and Related Minerals in the System, Kushner, W.R. (1990a): 1989 Summary Reporton the Oka Gold CaA12Si3Os-Si02-HzO Jouml of Petmlogy, Volume 12. Property, B.C. Ministry of Energy. MinesMdPetmleum Re- pages 379411. sources, Assessment Report 19,576. Lister. G.S. and Snoke,A.W. (1984): S-C MyloNtes; Jouml of Kushner, W.R. (199%): 1989 Summary Report on the Dokdaon Stmcrural Geology, Volume 6, No. 6, pages 617-638. Property; E.C. Ministry of Enem, Mines and Petroleum Re- Lloyd, C. (1989): Summary Report of the 1989 Exploration Pro- sources, Assessment Report 19,908. gramonthe~pidProperty;B.C.MinisrryofEne~,Mines :Kushner, W.R. (1991): 1990 Summary Report on the Oksa Gold andPetrolewn Resources, Assessment Report 19713. Property; B.C. Ministry Enem, Mines MdPetmleum Re- of Logan. J.M. and Drobe. 1.R. (1993a): Geology and Mineral Oc- sources, Assessment Report 20,840. currencesof the Mess Lake Area (IWGnW); in Geological lambert, M.B. (1974): The Bennett Lake Cauldron Subsidence Fieldwork 1992, Grant. B. and Newell, J.M, Editors, B.C. Complex, British Columbia and Yukon Territory;Geologi- Ministry of Energy, Mines and Petroleum Resources,Paper cal Survey of Canadn, Bulletin 227,213 pages. 1993-1, pages 135-148. lmmle. C.A.R. (1964): Geological Report on Mineral Claims Logan, J.M. and Drobe, J.R. (1993b): Geology of the Mess Lake BIK 117-136inclusive;B.C.MinistryofEnergy, Minesand Area, Northwestern British Columbia (104GnW): B.C. Petroleum Resources, Assessment Report 589. Ministry of Energy, Mines and Petroleum Resources, Open File 1993-6.

- Bulletin 95 125 Brifish Columbia

Logan. J.M., Dmbe, 1.R and McClelland,W.C. (In Preparation): McClelland, W.C. (1992): Permian and Older Rocksof the South- Geology along theFonest Kerr and Mess Lake Faults, Iskut westem Iskut River Map Area, Northwestern British Colum- River Area, Northwestern British Columbia (1048115. bia; in Current Research, Part A, Geological Survey of 104G/2&7); B.C. MinirtryofEnergy, MinesandPetmleum Cad.Paper 92-1A, pages 303-307. Resources, Bulletin. McClelland, W.C., Anovitz, L.M. and Gehrels, G.E. (1991): Ther- Logan, J.M. and Koyanagi, V.M. (1989): Geology and Mineral mobaromebic Constraints on the Structural Evolutionof the Deposits of the Galore Creek Area, Northwestern B.C. Coast Mountains Batholith, Central Southeastern Alaska; (104G/3&4); in Geological Fieldwork 1988, B.C. Minisfry Canadian Joumal of€arfhSciences, Volume 28, pages 9 12- of€nergy, Mines andPetmleum Resources, Paper 1989-1, 928. pages 269-284. McIntyre, J.F. (1966): Engineering, Geophysical and Geological Logan, J.M. and Koyanagi,V.M. (I 994): Geology and mineralde- Repon, ShakesEastand ShakesWest Groups;B.C. Ministry posits of the Galore Creek area; B.C. Ministry of Energ), ofEnerg), Minesand Pefmleum Resources, Assessment Re- Mines ond Pefrolewn Resources, Bulletin 92. port 773. Logan. J.M., Drobe, J.R. and Elshy, D. (1992a): Geologyof the McKenzie, K.J. (1985): Sedimentology and Stratigraphy of the MoreCreekArea.NorthwestemBritishColumbia(1MGn); Southern Sustut Basin,North-cend British Columbia;un- in Geological Fieldwork 1991, Grant,B. and Newell, J.M., published M.Sc. thesis, ?Ke (Iniversify ofBrifishColumbia, Editors, B.C. Ministry ofEnerg), Mines and Petroleum Re- 120 pages. sources, Paper 1992-1, pages 161-178. McMillan, W.J. (1978): Geology of the Guichon Creek Batholith Logan. J.M. and Dmbe, J.R. and Elsby, D.C. (1992b): Geology, and Highland Valley Porphyry Copper Disbict, British Co- Geochemistry and Mineral Occurrencesof Lhe More Creek lumbia; B.C. Ministry ofEnergy, Mines ond Permleurn Re- Area, Northwestern British Columbia (104G/2);B.C. Min- sources, Preliminary Map 30. istry of Energ), Mines and Petroleum Resources, Open File McMillan, W.J. (1992): Porphyry Deposiu in theCanadian Cor- 1992-5. dillera; in Ore Deposits, Tectonics and Metallogeny inthe Logan, J.M., Koyanagi, V.M. andDmk,J.R. (1990a): Geologyof Canadian Cordillera,B.C. Minisfry ofEnrgy, Mines and Pe- tbeForrestKerrCreekArea,NorthwesternBritishColumbia troleum Resources, Paper 1991-4, pages 253-276. (104B115); in Geological Fieldwork 1989,B.C. Ministry of McMillan, W.J. and Panteleyev, A. (1988): Porphyry Copper De- Energy, Mines and Petroleum Resources. Paper 1990-1. posits; in Ore Deposit Models. Roberts, R.G. and Sheahan, pages 127-139. P.A., Editors, Geoscience Canada, Reprint Series 3, pages Logan, J.M., Koyanagi,V.M. and Dmbe, J.R. (1990b): Geology, 45-58. Geochemistry and Mineral Occurrencesof the Forrest Kerr Macdonald, J.A., van der Hayden, P., Lefebure, D.V. and Alldrick, - Iskut River Area, NorthwestemB. C. (IMB110, 15); B.C. D.J. (1992): Geochronometry of the Iskut River Area - An Ministry ofEnerg), Mines and Petroleum Resources, Open Update(1MAandB);inGeologicalFieldw~1991,Grant, File 1990-2. B. and Newell, J.M., Editors,B.C. MinisfryofEnergy, Mines Logan, J.M., Koyanagi, V.M. and Rhys, D. (1989): Preliminary and Petroleum Resources, Paper 1992-1, pages 495-501. Geology and Mineral Occurrencesof the Sphaler Creekand Mamet, B.L. (1991): Report on Stikine Assemblage Samples; Re- Flood Glacier (1MG/3&4); B.C. Ministry of Energy, Mines port Misc02-BLM-1991, Universiry of Montreal. nndPetroleum Resources, open File 1989-8. Mandy, J.D. (1930): Stikine and Liard Mining Divisions;in Report Logan, J.M., Koyanagi, V.M. and Rhys, D. (1993a): Geology and of the Minister of Mines 1929; B.C. Ministry of Energy, Mineral Occurrences of the Galore Creek Area (NTS Mines and Petroleum Resources, page C115. IMG/03); B.C. Ministry of Energy, Mines and Petroleum Resources, Geoscience Map 1993-1. Mandy,J.D.(1931):StikineandLiardMiningDivisions;inReport of the Minister of Mines 1930; B.C. Minisrry ofEnerg3 Logan, J.M., Koyanagi, V.M. and Rhys, D. (1993b): Geology and Mines and Petroleum Resources, pages A117-119. Mineral Occurrences of the Galore Creek Area (NTS 101G/04); B.C. Ministq of Energy, Mines and Pefroleum Mark, D.G. (1970): Geochemical- Geophysical Reporton Mag- Resources, Geoscience Map 1993-2. netic and Soil SamplingSwey, Northern ValleyMines Lld.; B.C. Ministry of Energy, Mines and Pefmleum Resowres, Logan, J.M., Drok, J.R., McClelland, W.C. and Anderson, R.G. Assessment Report 2954. (1993~):Devonian Intraoceanic Arc Magmatismin North- westem Stikinia; Geological Association of Canada, Pro- Marsden. H. and Thorkelson,D.J. (1992) Geologyof the Hazelton gram with Abstracts. Vo1canicBeltinBritishColumbia:ImplicationsfortheEarly to Middle Jurassic Evolutionof Stikinia; Tectonics, Volume Long, D.G.F. (1981): Dextral Strike Slip Faults inthe Canadian 11, pages 1266-1287. Cordillera and Depositional Environmentsof Related Fresh- water Intermontane Coal Basins;in Sedimentation and Tec- Marud, D. (199oa): Reportof Activities on theTahltan Lake Prop tonics in Alluvial Bains, Miall, A.D., Editor, Geologica1 erty; B.C. Ministry of Energy, Mines and Petroleum Re- Assmiafionof Cam&, Special Paper 23, pages 153-186. sources, Assessment Report 20,149. Lueck, B.A. and Russell,J.K. (1994): Geology and Originsof the Marud, D. (199Oh): Report of Activities on the Dokdaon Creek Zippa Mountain Igneous Complex with Emphasis on the Property; B.C. Ministry ofEnegy. Mines andPetmleum Re- Zippa Mountain Pluton, Northern British Columbia;in Cur- sources, Assessment Report 20,153. rent Research Part A,Geo[ogicaI Survey of Canaaiz, Paper Marud, D. (19%): Report of Activities on the Rugged Mountain 94-1A. pages 77-85. Property; B.C. Ministry of Energy, Mines and Petroleum Re- McCIay, K. (1987): The Mapping of Geological Structures;Hal- sources, Assessment Repon 20,154. sled Press, John wiley & Sons, 161 pages.

126 Geological Survey Branch Mamd. D. (1990d): 1990 Assessment Report on the Gran 16 Mullan, A.W. and Bell, R.A. (1972): Report on InducedPolariza- Claim; B.C. Ministry of Energy, Mines and Petroleum Re- tion and Resistivity Survey, Project 124, Columbia River sources, Assessment Report20,302. Grid (Arc and Rose Claim);B. C. Ministry of Energy, Mines Miall, A.D. (1978): Tectonic Setting and Syndepositional Defor- and Perroleurn Resources, Assessment Report3986. mation of Molasse and other Nonmarine-paralic Sedimen- Mullen, E.D. (1983): MnOflXMP~05: A Minor Element Dis- tary Basins, Cadian Journal of Ennh Sciences, Volume criminant for Basaltic Rocksof Oceanic Environments and 15, pages 1613-1632. its Implications for Petrogenesis;Eanh and Planetary Sci- Miall, A.D. (1981): Alluvial Basins: Tectonic Setting and Basin ence Leners. Volume 36, pages 121-132. Architecture; in Sedimentation and Tectonics in Alluvial Ba-Neill, 1. (1992): Geology, Pemgraphy. and Chemistryof the Rug- sins, Miall, A.D., Editor, GeofogicafAssociafion of Can&, ged Mountain Alkaline Pluton, Northwestem British Co- Special Paper23, pages 1-33. lumbia (104GI13); unpublished B.Sc. thesis, The Universiry Mihalynuk. M.G., Smith, M.T. Hancock K.D.and Dudka, S. of Brifish Columbia, 75 pages. (1994): Regional and EconomicGeology of the Tulsequah Neill.I.andRussell,J.K.(1993):MineralogyandChemistryofthe River and Glacier Areas (104W12 & 13); in Geological Rugged Mountain Pluton: A Melanite-bearing AlkalineIn- Fieldwork 1993, Grant, B. and Newell. J.M., Editors. B.C. msion (104G/13); in Geological Fieldwork1992. Grant, B. Minisfry of Enew, Mines and Petroleum Resources, Paper and Newell, J.M., Editors, B.C. Ministry of Energy, Mines 1994-1.pages 171-197. andPefmleumResources, Paper 1993-1,pages 149-157. Miller, M.M. (1987): Displaced Remnantsof a Northeast Pacific Nelson, J. and Payne, J. G. (1984): Paleozoic Volcanic Assem- Fringing Arc: Upper Paleozioc Terranes of the Permian blages and Volcanogenic Massive Sulphide Deposits near McCloud FaunalAffinity, Western US.; Tectonics, Volume Tulsequah, British Columbia, Canadian Journal of Earth 6. pages 807-830. Sciences, Volume 21, pages 379-181. Monger, I.W.H. (1970): Upper Paleozoic Rocks of Stikine Arch, Nixon, G.T. and Rublee, VJ. (1988): Alaskan-type Ultramafic BritishColumbia;GeologicalSurveyofCanndn,Paper70-l, Rocks in British Columbia: New Conceptsof the Structure Part A, pages41-43. of the Tulemeen Complex; in Geological Fieldwork 1987, Monger, I.W.H.(1977a): Upper Paleozoic Rocksof Northwestern B.C. Ministry of Energy, Mines and Perrolewn Resources, British Columbia;PartA,GeologicalSurveyof Canada,Pa- Paper 1988-1,pages 281-294. per 77-1A. pages 255-262. Nixon,G.T.,Archibald,D.A.andHeaman,L.M.(1993):'Ar-39Ar Monger, J.W.H. (1977b): Upper Paleozoic Rocksof the Western and U-Pb Geochronometry of the Polaris Alaskan-type Canadian Cordillera and their Bearing on CordilleraEvolu- Complex, British Columbia: Precise Ttmingof Quesnellia - tion; CodianJournal of Earth Sciences Volume 14, pages North America Interaction;Geological Association of Can- 1832-1859. ada, Program and Abstracts, May, Edmonton, pageA-76. Monger, I.W.H. (1977~):The Triassic Takla Group in McConnell Nixon, G.T.. Ash, C., Connelly, J.N. and Case, G. (1989): Alas- Creek MapArea, Nortbsenual British Columbia;Geologi- kan-type Ultramafic Rocks in British Columbia: 2. The cal Survey of Canada, Paper 76-29.45 pages. Hickman, GnatLakes, and Menard Mafc-Ultramafic Com- plexes; in Geological Fieldwork B.C. Minisfry of En- Monger, I.W.H. and Irving, E. Northward Displacement 1988, (1980): ergy, Mines and Permfeum Resources, Paper 1989-1,pages of North-central British Columbia; Nature, Volume 285, 429-442. pages 289-293. Oliver, 1. and Gabites, 1. (1993): Geochronology of Rocks and Monger, I.W.H., Wheeler, 1.0.. Tipper, H.W., Gabrielse, H.. Polyphase Deformation, Bearskin (Muddy) and Tatsamenie Harms, T., Smik LC.. Campbell, R.B., Dodds, C.J., Ge- Lakes Dtstict. Northwestem British Columbia;in Geologi- hrels, G.E. and OBrien, Cordilleran Terranes;in l. (1991): cal Fieldwork 1992, Grant, B. and Newell, J.M., Editors, Chapter Geology of The Cordilleran Orogenin Canada, 8 of B.C. Ministry of Enew, Mines and Petroleum Resources, Gabrielse, H and Yorath, C.J., Editors,Geological Survey of Paper 1993-1,pages 177-183. Cda,Geology of Canada, No. 4, pages 281-327. Orchard,M.J.(1990):ReportonConodontsandotherMicrofossils IMorgan, D.R. (1973): Geological Report on the B #I-IO and the Collected by the B.C. Geological Survey: GeologicalSurvey BM #13-16,25-28.3740and 49-53 Claims of Bart Mines, of Can&, Report No. MJOiNov90. Ltd.; B.C. Minisfry of Energy, Mines and Petroleum Re- sources, Assessment Report4717. Orchard.M.J.(1992):ReportonConodontsandotherMicrofossils Collectedby the B.C. Geological Survey; GeobgicaalSurvey Morgan, J.T. (1976): Geology of the Ten Mile Creek Syenite - of Conado, Report Number Pyroxenite Pluton, Telegraph Creek, B.C.; unpublished OF-1992-26.. B.Sc. thesis, The Universily of British Columbia, 42 pages. Panteleyev, A. (1975): Galore Creek Maparea; in Geological Fieldwork 1974. B.C. Minisfry of Energy, Minesand Poro- Irlorrison, G.W. StratigraphicControl of Cu-Fe SkarnOre (1974): Ieum Resources, Paper pages Distribution and Genesis at Craigmont, British Columbia; 1975-2, 59-62. CdianInsfitute of Mining andMefallurgy, Bulletin,Vol- Panteleyev, A. (1976): Galore CreekMaparea, Geological Field- ume 73, pages 109-123. work, 1975, B.C. Minisfry of Enevy, Mines and Perroleurn Resources, Paper 1976-1,pages 79-82. Morrison. G.W. (1980):Characteristics and Tectonic Settingof tbe ShwhoniticRockAssociation;Lifhos,Volume13,pages97- Panteleyev. A. and Dudas, B.M.(1973): Sno,Bird (Liard Copper); 108. Nabs (Paramount);in Geology, Exploration and Mining in Brifish Columbia 1972,pages 527-528. Mortimer, N. (1987): The Nicola Group: Late Triassic and Early Jurassic Subduction-related Volcanismin British Columbia; Pearce, J.A. (1983): Role of the Sub-continental Litbosphere in Canadian Journal of Eonh Sciences, Volume 24, pages Magma Genesis at Active Continental Margins;In Hawkes- 2521-2536. worth, C.J. and Norry,MJ., Editors, Continental Basalts and Mantle Xenoliths; Shiva PublicationsDd.. pages 230249.

bulletin 95 127 British Columbia

Peawe, J.A. and Cann, J.R. (1973): Tectonic Settingof Basic Vol- morphism, Contact Metamorphism and Hydrothermal Al- canic Rocks Using Trace Element Analyses; Earth and teration; GeologicalSociety of America, Bulletin, Volume Planetary ScienceLeners. Volume 19, pages 290-300. 99, pages 471479. Pearce, J.A. and Now, M.J. (1979): Petrogenetic Iimplications of Rennie, C.C.(1 %2): Copper Depositsin the Nicola Rocks,Craig. X,21, Y and Nb Variations in Volcanic Rocks; Contributions mont Mine; Western Miner & Oil Review, Fehurary, pages to Mineralogy andPermlogy,Volume 69, pages 33-47. 50-52. Pearce, J.A., Harris, N.B.W. and Thdle, A.G. (1984): Trace Ele- Rhys, D.A. and Godwin, C.I. (1992): PreliminarySmctural Inter- ment Discrimination Diagrams for the Tectonic Interpreta- pretation of the Snip Mine(IME/II); in Geological Field- tion of Granitic Rocks; Journal of Petmlogy, Volume 25, work 1991, Grant, B. and Newell, J.M., Editors, B.C. Part 4, pages 956-983. Ministry of Energy, Minesand Petmleum Resources, Paper Perchanok, MS. (1980): Reconnaissance of Glacierdammed 1992-1, pages 549-554. Lakes in the Stikine and Iskut River Basins; National Hy- Ross, T.V. (1989): Geological and Geochemical Report on the drology ResearchInstitute, Inland Water Directorate, Envi- Scud River Project;B.C. Ministry of€nergy, Minesand Pe- ronment Canada, 32 pages. tmleum Resources, Assessment Report 19516. Phelps. G.B. and Gutrath, G.C. (1972): Report on a Geological, Rust B.R. (1980a): Facies Model 2. Coarse Alluvial Deposits;in Geochemical and Magnetometer Survey of the Arc, Port and Facies Models, Walker, R.G. Editor, Geoscience Canada, RoseClaimGroups;B.C. MinistryofEnergy, MinesandPe- Reprint SeriesI, Second Printing, pages 9-21. tmleum Resources, Assessment Report 3985. Rust, B.R. (1980b): Alluvial Deposits and Tectonic Style: De- Pitcher, M.G. (1960): Fusulinids of the Cache Creek Group, vonian and Carboniferous Successionsin Eastern Gas+; in Stikine RiverArea, Cassiar District, British Columbia, Can- Sedimentation and Tectonics in Alluvial Basins, Miall, A.D., ada; unpublished MSc. thesis, Brigham Young University. Editor, GeologicalAssociationofCan~,Special Paper23, 64 pages. pages 49-76. Pitcher, W.S. (1982): Granite’&x and Tectonic Environment;in Ryan, B. (1991): Geology and Potential Coal and Coalbed Meth- Mountain Building Processes, Hsu, K.J., Editor, Academic ane Resource of the Tuya River Coal Basin (1MJR.7); in Press, pages194. Geological Fieldwork 1990,B.C. Ministry of Energy Mines Preto, V.A. (1977): The Nicola Group: Mesozoic Volcanism Re- and Petroleum Resources, pages 419-429. lated to Rifting in Southern British Columbia;in Volcanic Ryder, J.M. (1984):Terrain Inventory for the Stikine-Isht River Regimes in Canada, Barager, W.R.A., Coleman, L.C and Area(NTSI04F.1MGandparlsof104Band1MH);B.C. Hall, J.M., Editors, GeologicalAssociation of Canado, Spe- MinistryofEnvimnment,LrmdsandParlrr,TechnicalReport cial Paper 16,p. 39-57. 11.85 pages. Ray, G.E., Jaramillo, V.A. andEttlinger, AD. (1991): me McLy- Salat, M.H. and Noakes, D.J. (1979): GeoIogical, Geochemical mont Northwest Zone, Northwest British Columbia: A Report on He1 Claims; B.C. Ministry ofEnergy, Mines and Gold-rich Retrograde Skam? (IMB); in Geological Field- Petroleum Resources, Assessment Report 7708. work 1990, B.C. Ministry of Energy Mines andPetroleum Schielly, H. (1972): Report on a Geological Survey doneon the Resources, Paper1991-1, pages 255-262. PR Gmup; B.C. Ministry of Energy, Mines and Petmleum Ray, G.E., Webster, I.C.L., Dawson, G.L. and Ettlinger, A.D. Resources, Assessment Report 3846. (1993): A Geological Overviewof the Hedley Gold Skam Schroeter, T.G. (1987): Golden Bear Project:in Geological Fkld- District Southem British Columbia (92H); in Geological work 1986, B.C. Minisrry of Enew, Mines and Petroleum Fieldwork1992,GranrB.andNewell,J.,Editors,B.C.Min- Resources, Paper 1987-1, pages 103-109. istryofEnergyMinesandPetmleumResources,Paper1993- 1, pages 269-279. Seraphim, R.H., Sutherland Brown, A. and Grove, E.W. (1976): Discussion of “Geology of the Schaft Creek PorphyryCop Read RB. (1983): Geology, Classy Creek (IMJIZE and Stikine per and Molybdenum Deposis Nolth-western B.C.”;in Lin- Canyon (104JRW). British Columbia; GeologicalSurvey of der, H., Canadian Institute of Mining and Metallurgy, Canada, Open File 940. Bulletin, Volume 69, pages96-99. Read P.B. (1984): Klastline River (104G/l6E). Ealue Lake Shand, SJ.(1951): Eruptive Rock, J. Wky. New York. (104W13W). Cake Hill (1041/4W), and Stikine Canyon (104111E); Geological ofcanada, Open File1080. Shedock, R.L.. Childe, F., Barret!. TJ., Mortensen, J.K., Lewis, Survey PD., chandler, T., McGuigan. P.. Dawson, G.L. and Allen, Read P.B. and Okulitch,A.V. (1977): TheTriassicUnconformity R. (1994): Geological Investigations of Tulsequah the Chief of South-central British Columbia; Canadian Journal of Massive SulphideDeposit, Northwestern British Columbia Eanh Sciences; Volume 14, pages 606-638. (104W12); in Geological Fieldwo* 1993, B.C. Ministry of Read P.B., Brown, R.L., Psutka, J.F., Moore, J.M., Journeay, M., Energy, Mines and Petroleum Resources, Paper 1994-1, Lane, L.S. and Orchard, M.J. (1989): Geology, More and pages 371-377. ForrestKerrCreeks@~of1MB/10,15,16&1MG/1,2), Shervais,J.(1982):li-VPlotsandthePetrogewsisofModernand Northwestern British Columbia; GeologicalSurvey of Can- Ophiolitic Lavas; Earthand Planetary ScienceLeners, Vol- ada, Open File 2094. ume 59, pages 101-118. Read P.B., Psutka, J.F., Brown, R.L. and Orchard, M.J. (1983): Sibson, R.H., Robert,F. and Poulsen,K.H. (1988): High-angle Re- ‘Tahltanian” Orogeny and Younger Deformations, Grand verse Faults, Fluid-pressure Cycling, and Mesothermal Canyon of the Stikine British Columbia; GeologicalAsso- Gold-QuartzDeposits; Geology, Volume 16, pages551-555. ciation of Canada, Programs with Abstracts, May 11-13, Victoria, Volume 8, page A57. Simpson, C. and Schmid,S.M. (1983): An Evaluation of Criteria to Deduce theSense of Movement in Sheared Rocks;Geo- Rejebian, V.A., Harris, A.G. and Huebner,J.S. (1987): Conodont Color and Textural Alteration:An Index to Regional Meta-

128 Geological Survey Branch ~

Minisfry of Employment and Investment

logicalSocietyofAmericaBulletin,Volume94,pages1281- Sutherland Brown, A. (1971): Sno, Bird (Lid Copper); in Geol- 1288. ogy,ExplorationandMininginBritishColumbia1970,B.C. Smith, J.G. (1977): Geology of the KetchikanD-l and Bradfield Minisrry of Energy, Mines and Petmkurn Resources, pages Canal A-l Quadrangles, Southeastern Alaska,US. Geologi- 49-57. cal Survey, Bulletin 1425.49 pages. Sweet, A.R. (1989): Report on5 Samples fmmthe Susblt Gmup; Smith, P.L., Thomson, R.C. and Tipper, H.W. (1984): Lower and Geological Survey of Canada, Paleontology Subdivision, MiddlelurassicSedimenrsandVolcanicsintheSpatsiziMap Calgaty, Report AS-19896. Area, British Columbia; in Current Research, Part A, Geo- Sweet, A.R. (1990): Report on 5 Samples from the Sustut Group; logical Surveyof Canada, Paper 84-1A. pages 117-120. Geological Survey of Cad,Paleontology Subdivision, Southam, P. (1991): 1990 Exploration Report onthe Tahltan Lake Calgary, Report AS-90-08. Property (Canyon 1-20, nil,TL-2 and lL3claims); B.C. Thomson,R.C,Smith,P.Landlipper,H.W.(1986):LowertoMid- Ministry of Energy, MinesandPermleum Resourres.Assess- dle Jurassic (pliensbachianto Bajocian) Stratigraphyof the ment Report 21,320. Northem Spatsizi Area, Northcentral British Columbia; Ca- Souther, J.G. (1959): Chutine; Geological Surveyof Canada, Map nadian Journal of Earth Sciences. Volume 23. pages 1963- 7-1959. 1973. Souther, I.G. (1970): Volcanism and its Rlationship to Recent Thorstad. L.E. and Gabrielse, H. (1986): The Upper Triassic CNSC~I Movementsin the Canadian Cardillera, Canndian KutchoFormation.CassiarMountains.NorthsentralBritish Journal of Eanh Sciences, Volume 7, pages 553-568. Columbia, GeologicalSurvey of Canada, Paper 8616.53 pages. Souther, J.G. (1971): Geology and MineralDeposits ofTulsequah Map Area; Geological Surveyof CaMdn, Memoir 362.76 Tipper. H.W. (1989): Unpublished repon on Jurassic fossils: Geo- pages. logical Surveyof Cda,Report J4-89-HWT. Souther. J.G. (1972): Telegraph Creek Map Area; British Colum- lipper, H.W. and Richards, T.A. (1976): Jurassic Stratigraphy and bia. Geological Survey of Canada, Paper714.38 pages. History of Northsenml British Columbia; GeologicalSur- vey of Conado, Bulletin270,73 pages. :Souther, J.G. (1977): Volcanism and Tectonic Environmentsin the Canadian Cordillera- A Second Look;in Volcanic Regimes Tuttle,O.F.andBowen,N.L.(1958):OriginofGraniteintheLight ofCanada, Baragar, W.R.A.. Coleman, LC. and Hall, J.M., of Experimental Studies in the System NaAISi3Os- Editon, Geological Association of Canada, Special Paper KAISijOs-SiOz-HzO, GeologicalSocieryofAmerica,Mem- 16, pages 3-24. oir 74, 153 pages. Souther.J.G.(1988):MountEdzizaVolcanicComplex,BritishCo- Tozer, E.T (1989): Report on Fossils from the Telegraph Creek lumbia; Geological Survey of Canada, Map 1623A. Area; Geological Surveyof Canada, ReportTI 9 ETT 1989. Ulrich. G.D. (1971): Report on Geological, Geochemical Souther, J.G. (1992): The Late Cenozoic MountEdziza Volcanic and Geophysical Surveys and Physical Work Done on the Complex, British Columbia; Geological Surveyof Canada, Memoir 420,320 pages. EmpireMetalsCorporationLtd.(N.P.L.)~rty,Dokdaon Creek, B.C.; B.C. Ministryof Enem, Mines andPetmleum Smther. J.G. and Symons, D.T.A. (1974): Smtigraphy andPaleo- Resources, Assessment Report 3238. magnatism of Mount Volcanic Complex, Northwest- miza Ulrich.G.D.(1971):ReportonGeological.GeochemicalandGeo- ern British Columbia; Geologic01 Surveyof CaMda, Paper physical Surveys and Physical Work on Dokdaon Creek 73-32,48 pages. Area; B.C. Minisrry of Energy, Mines and Petmleum Re- Souther, J.G. and Yorath, C.J. (1991): Neogene Assemblages, sources, Assessment Report 3238. Chapter IO in Geology of the Cordilleran Orogenin Canada, VandalI,T.A.,Brown,D.A. andmeaton, P.M. (1992): Paleomag- Gabrielse, H. and Yorath, C.J., Editors, Geological Survey netism of Toarcian Hazelton Group Volcanic Rocks in the of Canada, Geology of Canada, No. 4, pages 373-401. Yeh~o~eArea(l04Glll,l2):APreliminaryReport;in Souther,J.G., Armstrong, R. L. and Harakal, 1. (1984): Chronology GeologicalFleldworlt1991,Grant,B.andNewell,J.M.,Edi- of the Perahline, Late Cenozoic Mount Fdziza Volcanic tors, B.C. Ministry of Energy, Mines and Petroleum Re- Complex, Northern British Columbia, Canada; Geological sources, Paper 1992-1, pages 213-220. Society ofAmerica Bulletin, Volume 95, pages 337-349. Van Angeren, P. (1991): Assessment Reporton the 1990 Explora- Spner, I.S. (1994): Quaternary Climate Change in the Stikine tion Results (Geology, Geochemistry and Drilling) of the Plateau Region, Northwestern British Columbia; unpub- Goat4toGoat7Claims;B.C.MinistryofEnergy,Minesand lished PhD. thesis, University of Calgary,. Petmleum Resources, Assessment Report 20,988. Sreiger, R.H. and lager. E. (1977): Subcommission on Geochro- Veitch, J. (1970): Geological Report for Canadex MiningCow nology: Convention on the Useof Decay Constanrs inGeo- ration, Lld. on the EWK 1-4, LLK 1-4. WK1-36 Claims; and Cosmochronology; Eanh and Planetary Science Let- B.C. Ministry of Energy, Mines and Petmleum Resources, ters, Volume 36. pages 359-3152, Assessment Report 3029. Stevens.R.D.,Delabio, R.N. andLachance,G.R. (1982): AgeDe- Webster. I.C.L. and Ray, GE. (1991): Skams inthe Iskut River - terminations and Geological Studies, K-AI Isotopic Ages; Scud River Region, Northwest British Columbia (104B. G); Geological Surveyof Canada, Report16, page 4. in Geological fieldwork 1990; B.C. Ministry of €new, Strain, D.M. (1981): Geological and Geochemical Reporton the MinesandPetmleum Resources, Paper1991-1. pages 245- Tuff Claims;B.C. Ministry of Energy, Minesand Permleum 253. Resources, Assessment Report 9200. Westcott,M.G.(1989a):GeologicalandGeochemicalWorkonthe Swckeisen, A. (1976): To Each Plutonic Rock Its Proper Name; TRI 5-7, 9 andRUSH 5-8, 23-24 Claims; B.C. Ministry of Eanh Science Reviews, Volume12, pages 1-33. Energy, Mines and Permleum Resources, Assessment Re- port 19.143.

Bullerin 9S I29 "_...... I_._ ~.

British Columbia

WestcogM.G. (1989b): Geological and Geochemical Workon the White, W.M.. Harakal, J.E. and Carter, N.C. (1968): Potassinm- Poker 1-7 Claims;B.C. Ministry of Enem, Mines and Pe- Argon Ages of Some Ore Deposits in British Columbia:Ca- tmieum Resources,Assessment Report 19,247. diunInsritute ofMining and MetaIfurn, Bulletin, Volume Whalen, J.B., Me,K.L. and Chappell, B.W. (1987): A-type 61, pages 1326-1334. Granites: Geochemical Characteristics, Discrimination and Woodsworth, GJ., Anderson, R.G., Annsmng, R.L. Smik LC. Petrogenesis: Contributions to Mineralogy and Petrology, and van der Heyden,P. (1991): Plutonic Regimes; in Chap Volume 95, pages407419. ter 15 of Geology of the Cordilleran Orogen in Canada, Wheeler, J.O. (1961): Whitehorse Maparea, Yukon Territory Gabriel=, H. and Yorath, CJ., Editors, Geological Survey (IOSD); Geological Survey of Canada, Memoir 312, 156 of Cad,Geology of Canada, No.4, pages 491-531. pages. Wyld, SJ. (1991): Penno-Triassic Tectonism in VolcanicArc Se Wheeler, J.O. and McFeely,P. (1991): Tectonic Assemblage Map quences of the WestemU.S. Cordillera and Implications for of the Canadian Cordillera and Adjacent ofParts the United the Sonoma Orogeny; Tectonics, Volume 5. pages 1007- States, Geologicul Survey of Canada, Map 1721A. 1017. White, WM.H. (1959): CordilleranTectonicsin British Columbia; Yorath, CJ. (1991): Upper Jurassicto Paleogene Assemblages,in American Association of Petroleum Geologists Bulletin, Chapter 9of Geology of the Cordilleran Orogenin Canada, Volume 43, pages 60-100. Gabrielse, H. and Yorath, CJ., Editors, Geological Survey of Canada, Geology of Canada, No.4, pages 331-371.

130 Geoiogicol Survey Branch Ministrv of Employment Md lnvesrmenr

APPENDICES

Befferin95 131 APPENDIX 1 MACROFOSSIL IDENTIFICATIONS

M AP FIELD MAP GSC UTMNTS Zone 09 DESCRIPTION OF FAUNA REF. CODE NO. NO. MAP EAST NORTH - HMELTON GROUP IJHs CGR89-250C168017 1MG12 349990 6385659 belemnites, ammonile (Haugiasp. or Pleydaiiia?), Osfreasp. Early Jurassic.m. - I. Toarcian 2A IJHs OBR89-327IJHs C158943 IWGH 354706 6381236 Bags. of Weyla. true belemnites(?). brachiopods, coieoids Early Jurassic, pass.Toarcian 3A IJHs DBR89-423-1 C168M8 104011 354726 6381282 Terebratuiid brachiopods(l~bofhyri~ponccafasubpunc(ala) L. Jurassic. I. Pleins.-Toarcian 4 IJHs DBR89-423-2C168048 1WG11 354726 6381282 bivalves: Meleagrinella sp.(7) and Pecfensp. Late Triasriklurassic 3A IJHs DBR89-423-3IJHs C168049 1WG11 354726 6381282 belemnites. bivalves, gastropod Toarcian to late Early Cretaceous 3A IJHs OBR89-424IJHs C168050 1WG11 354787 6381410 ammonite: flanened Hammabcerassp.?; bivalves late(?) Toarcian 3A lJHs DBRW-155 C168072 1WG11 354584 6381575 )ale(?) Toarcian 3 STUHlNl OROUP uTSsl OBR91-1-3C189817 1WG13 344443 6411542 Halobia Carnian 1B uTSs1 OBR91-151C189816 104G13 344240 6411681 Hsiobia. Psrihalobia? early Norian 1B uTSslDBR9l-274 C189815 1WG13 339527 6406037 Halobia Carnian 1B UTSs1 DBR9l-281 C189818 1WG13 340481 6405709 Halobia Carnian 1B uTSsl DBR91-281-2 C189812104G13 340481 6405709 Halobia Carnian 1B uTSs2CGR69-168 C168014 104G12 351657 6389893 poorly preserved bivalves(?) indeterminate 1A uTSs2 CGR69-170 C168015 IWG12 351657 6389893 corals(?) indeterminate 1A uTSs2CGR89-178 C168016104G12 351614 6389732 bivalve indeterminate 3A uTSv CGR89-260 C168018 IWG11 345571 6400983 corals indeterminate 3A uTSs1 CGR89-302 C168020 104G12 340607 6399452 terebratulid(7). bivalve.crinoa hagments possibty Triassic 3A uTSv CGR89-454 C168023 104011 347500 6389101 nothing determined indeterminate 1A

uTSsl~ ". OBRR9-48~~ .. C16RO2R... . " . 1MC.12. . - .- 3dR35.3...... 6400672 "Pecfen"sp.. spiriferid brachiopod probably Lale Triassic 1A uTSs2 DBR09-157 C158938 1WG11 349589 6389142 Monolis Subcircularis Gabb late Norian 1A 63892ML Myophodgonia sp. Late Triassic. pmb.late Norian 1A 6389147 Monofissp. late Norian 1A 6403101 Perihalobiasp., Slikinocerassp. early Norian 1A 6379515 MMisalaskana Smith late Norian 1A

...... - ...... " 6378763 fragmentaryspiliferidbrachiopod, coral fragmenls probably LateTriassic IA uTSv DBR89-353 C158W 1WG12 336853 6395239 Wliy preSeNed pectinids indelerminate 1A UTSV DBR89-510 C167907 1WG12 345979 6399421 crushed serpenliconemmonitewilh simpkribs Triassic or Jurassic 1A 6400424 ragmenls 01 wiferid brachiopods prob. TTiassic 1A 6400372 fragments of anmonoid: Griesbachiles(7); indeter. bivaives prob. Late Triassic 1A 6400372 mmonites: Griesbachifes 2sp.: Slikinoceras sp. prob. early Norian 1A 6375670 Manotis subcircularisGet Late Triassic,lale Norian, Cordilkranus zone 1B

~ 1PSc CGR89-398C168M1 1WG12 335482 6402326 nothing determined indeterminate 1A lPSc DBR86-010-1 C159118104G05 Yffi02 6351685 Bothrophyllid coral, fusulinaceanforaminifers Lata Carboniferousor Permian 2A 1PSc DBR88-010-3 C158910104G05 348608 6351665 Tabulate coral, possibly Molfifhecopora sp. Late Carboniferousor Permian 2A IPSc DBR86-117-1 C159141 1MG05 350625 6350300 Herifschioides sp(coral). Ienesbate bryozoans. Permian, probably Early Permian 2A bothrophyilid corals. lusulinaceans foraminifers lPSc DBR88-118-1 C159142 1WG05 350901 6350357 Climiophyllid coral, schwagerinid. fusulinacean foraminifers Early Permian 2A lPSc DBR86-123-1 C158913 1WG05 349794 6349995 Fusulinaceanfominifen Late Carb.or Perm.. probably 2A not older than Mmcovian IPSa DBR88-131-2 C159121104G05 348130 6351100 Indeterminate syrirgipora coral probably Carboniferous or Permian 2A lPSc DBR86-164-2 C158144IWGOB 351414 635M01 Indeterminate bryozoans. schwagerinid. fusulinacean foraminifers Early Permian 2A lPSc DBR86-166-2 C159145 1WG06 351268 6350105 Indeterminate tabulatecorals. fusulinacean foraminifers Late Carb. w Perm.. pr&ably 2A

not~~~~ older than ~~~ Mmcovian~~~~~.~ 1PScOBR86-189-1 C159146 104GOB 351030 6350365 Fusuilnacean foraminifers Probably Permian.could be 2A as aid as Mascavlan lPSc DBR88-250-1 C159148104G06 356474 6353463 Indeterminate solidary coral, fusulinacean foraminifers. Permian. probablyAninskian or younger 2A 1PSC DBR86-251-1C159149 1MG06 358400 6353471 Indeterminate lophophyllii coral, schwagerinid. fusulinacean foraminifers Permian, probabiyArtinskian or younger 2A lPSc OBRB8-332-1 C159147 1MG05 350514 6350320 Bofhrophyllum sp(coral). indeterminate fenestrale and Permian 2A ranching bryozoans. rhynchoneliid brachiopods, gastropod, schwagerinid fusulinacean foraminifers 1PSc MMC88039.1 C15426.2104G08 352470 6347570 Solitary rugose coral. fusulinacean fwaminifen Late Carbaniferaus or Permian, probably Earty Permian uCS? MGU88087-1 C156903 104G05 340618 6357169Echinoderm colmnals Indelerminale 1PSc MGU88lW-1 C158W 104G06 350472 6350814 Indeterminate fenestellid bryozoans. echinoderm colmnal Ordovician to Permian lPSc MGU88199-1 C158905 1WG06 350453 6350693Echinoderm mlmnals Indeterminate tPScMGU68200-1 C158w6 104G06 350280 6350381 7Herirschioides ap, schwagerinid fusulinacean foraminifers Permian, probabb Early Permian 1PSc MGU88202-1 C158908 1WG08 350351 6350343 Bothrophyllii coral. echlooden coIm~b. Permian schwagerinid fusulinaceanfwaminifers 1PScMGU88203.1 C158909 1MGW W26350345 7Bolhrophyllorn sp, achwagerinid furulinacean forminifen Permian uCSs MGU8964 C158922 1MG12 339007 6402542 Bothrophylli wralr. schwagerinid(7). fusulinacean forminifen probably earty Permian uCSs MGU89140 C156927 lMG12 340524 6381697 wrais, Fomichevellasp. and Arachnolasrna(7) sp. Carboniferous uCSs MGU8S142 C168085 104G12 340555 6380961 Bolhrophyllid corab. labulale coral Carboniferous 1PScMGU69-349 C166M9 1MGm5 348651 6350874 Bolhrophyllid corab. bryozoans, brachiopods. schwagerinid Permian, Artinskian or younger fusulinacean foraminifers 1PSc MGU89353 C1660331MG105 348370 6351229 Bolhrophyllid coralr. syringopomid coral, gastropods, nodosarkl Early Permian foraminifers. schwagerinid fusuiinaceanforaminifen 1PSc MGU89-355 C166086 104G105 349636 6351263 Schirophoriasp.. ncdosarid foraminifen Permian IPSc MGU89.378 C168054 1WGi08 355381 635WO Gastropods probably Permian lPSc MGU89-383 C168068 104G106 358499 6353502 Solitary coral, schwagerinid fusulinacean foraminifers Permian, Artinskian or younger

REFERENCES: I .E.T. Tozer. Geolcgical Survey of Canada; A = Report TR-MTT-1989: E = Report ETT-19952. 2. E.W. Bamber. lnslilute of Sedmentary and Pelrolewn Geology. Paleontolcgy Subdivision, Calgary,Aberta: A IReporl C2-EWE-1988; B = Report Cl-EWE-t990. 3. t{.W.Tippr,GcologicalSuncyofCanada, Vmcouver;A= Report 1449-HWT. 4. D.Ager, wrillcncommunicaIion. 1989. British Columbia

134 Geological Survey Branch Ministy of Employmen1 and Investment

APPENDIX 2 FUSULINACEAN AGE DETERMINATIONS

FIELDNTS GSC UTM Zone09 AGE REF. NO. NO. MAP EAST NORTH

DBR88-132-2 CIS9123 104GOS 348010 6351148 early Lconardian (Aninskian) DBR88-I 17 c159141 104G06 350625 6350300 middle to late Wolfcampian (Asselian-Sakmarian) DBR88-123 CIS8913 104G06 349794 6349995 middlc to law Wolfcampian (Assclian-Saharian) DBR88-I25 CIS8914 104G06 349358 6350114 carly Cuadalupian (Wordian) DBR88-126-1 C158915 104G05 349154 6350206 early Guadalupian (Wordian) MGU88-203-1 CIS8909 104G06 350442 6350345 middlc to late Wolfcampian (Arsclian-Sakmarian) MMC88-039-1 CIS4262 104G06 352470 6347570 middle to late Wolfcampian (Arrclian-Sakmarian) DBR88-332-1 CIS9147 104C05 350514 6350320 middle to Ia1c Wolfcampian (Assclian-Sahmarian) DBR88-IM-I CIS9143 104G06 351416 6350418 middlc 10 latc Wolfcampian (Arselian-Sakmarian) DBR88-164-2 CIS9144 104C06 351414 6350401 middle 10 late Wolfcampian (Assclian-Saharian) DBR88-166-2 c159145 104G06 351268 635041 I Wolfcampian (?) (Asrclian-Saharian) DBR88-169-1 CIS9146 104G06 351030 6350365 middlc io late Wolfcampian (Arselian-Saharian) DBR88-I 18-1 CIS9142 104C05 350901 6350357 middle 10 laic Wolfcampian (Asselian-Sakmarian) MGU88-201-1 CIS8907 104G06 350280 6350361 middlc 10 late Wolfcampian (Assclian-Saharian) MGU88-202-1 CIS8908 104G06 350351 6350343 middle 10 late Wolfcampian (Assclian-Saharian) MGU89-349 C168029 104co5 348651 6350874 early Guadalupian (Wordian) MCU89-353 C168033 104GO5 348370 6351229 Lconardian (Aninrkian-Roadian) MGU89-383 C168068 104GO6 358499 6353502 early Guadalupian (Wordian) DBR88-131-1 c159120 l04G05 348112 6351 I12 Leonnrdian(?) (Aninskian-Roadian) DBR88-010-1 CIS9118 104G05 348602 6351685 Leonnrdian (Aninskian-Roadian) DBR88-010-2 CIS9119 104G05 348602 6351685 carly Lconardian (Aninskian) DBR88-250-1 CIS9148 104G06 358474 6353463 carly Cuadalupian (Wardian) DBR88-251-1 CIS9149 104G06 358400 6353471 carly Guadalupian (Wordian) DBR88-252-1 CIS9150 104C06 358372 6353514 early Cuadalupian (Wordian) MMC88-046-1 CIS4263 104G06 354315 6347603 Wolfcampian (?) (Asrclian-Sakmarian) DBR91-340 C189813 104GIZ 325715 6396977 early Wolfcampian (Asrelian) INE91-144 C189814 104C12 327344 6402893 middlc Lconardian (Aninskian) MCU89-64 c I58922 104G12 339087 6402542 laic Wolfcampian (Sakmarian)

IREFERENCES: I. = Lin Rui, Repon Number I-RUI- 1990, ISPG Calgary. Albcm. :1. = Lin Rui. Rcpn Number 5-RUI-1991, ISPG Calgaly. Alberta. :i.= Lin Rui. Repon Number 1-RUI-1992. lSPG Calgary, Albcna.

”* faunal lisu arc available upon rcqucrt.

‘I**Time chan from Cancr el ol. (19911; thosc in bcackcrs are from Harland el ol. (1989).

tru11erin 95 135 Brirish Columbia

~ ~~ 136 Geological Survey Brunch APPE~NUiX CONODONT IDENTIFICATIONS

MAP FIELD NTSGSCNo.1 UTM ZONE 09 DESCRiPTlONOFFAUNA AGE CAI REF. CODE NO. MapNo. MAP EASllNG NORTHING STUHlNl uTSsl CGR69-171 C-166OW 1MG112 351657 6389693 Epigondolella ex gr. bidenlala (Mosher) Late Triassic. late Norian 2.0-3.0 1 uTSs2 CGR69-232 C-166007 1WGH2 357021 6361053 blade flagmen1 7 Ordovician - Triassic 1 L1 CGR69-260-1 C-1660@3 1WG112 345571 6400983 Mefapolygnalhus pnmifur (Masher) Lale Triassic, iale Camarea* Nwim -3.0 1 L1 CGR69-260-2 C-166009 1WGI12 345571 6400983 Mefapolygnalhus? sp. Lale Triassic 2.0-3.0 1 L1 CGR69-261 C-166010 1WGI11 346037 6401176 Mefapolygnalhus? sp. Lale Triassic 2.0-3.0 1 uTSs2 CGR69451 C-166022 1WGH1 347639 6366801 Epigondolella sp. Laie Triassic. madle-late Norian 2.0-3.0 1 u DBR69-267-2 C-167912 lWGlll 353320 6379515 Eplgondolella ex gr. bidenfala (Masher) Lale Triassic. lale Norian -4.0 1 uTSs1 DBR6949 c-158919 1WGI12 346274 6400792 Epigondolella n. sp. c Orchard Late Triassic. Middle Norian -3.0 1 Ll DBR89-527 C-167915 1WG112 344216 84wP24 Mefapolvgnalhuspn~~ius(Mosher) Lale Triassic. iale CarnialFearly Nwian 3.M.O 1 uTSs1 DBR69-VB-3 C-167916 1WG112 344201 6400372 Melapolygnafhus prim,rrus (Mosher) Lale Triassic. late CarnialFearly Norian 3.0-4.0 1 UTS51 DBR91-5 C-166096 1WGH3 344430 6412093 Neogondolella? sp. Triassic 67 2 L1 OBR91-128." C-166097 1WG113 344859 6424406 Melapolygnafhussp., ramifom ehenls Lale Triassic. lale Carnian 5.56.0 2 L1 DBR91-242 C-169603 1WG113 338667 6406402 Melapolygnafhusnodosus(Hayashi 1966) Lale Triassic,lale Carnian 5.0 2 uTSsl DBR91-271 C-166073 1WGH3 339475 6406661 Melapolygnalhussp. cl..M. nodosus(Hsyashi 1986) Lale Triassic, lale Carnlan 4.55.5 2 uTS5l DBR91-280 C-189602 1WGl13 340451 6405804 Melaplygnefhussp.. ranifon elements Lale Triassic. Carnian 5.0 2 L1 DBR91-296 C-166075 1WGl13 340769 6426290 Msfaplygnafhus spp.,lNeospafhodu# sp. Lale Triassic, Iale? Carnian 5.5.7.0 2 L1 DBR91-322 C-169601 1WGl13 331667 6404574 Mefapolygnalhussp.cf. M. nodosus (Hayashi 1966) Lale Triassic. laie Carnian 5.0 2 L1 DER91403 C-169606 1MGl13 343012 6423958 Mefapolygnalhusexgr. nodosus(Hayashi1966). rmilorm element Lale Triassic. lale Carnian 5.0 2 L1 DBR91449 C-166088 1MGll3 326794 6421791 Melapolygnafhus sp. Lale Triassic. Carnian 5.0 2 LO iNE91-130 C-166095 1MGl13 336146 6425026 Mefapolygnafhus ex gr. polygnalhifonnis(Budurav and Slefamv 1965) Laie Triassic, early Carnian 4.5-5.5 2 LO INE91-130 c-1mas 1MGf13 336148 6425028 Mefaplygnafhus ladpota (Hayashi1968) LO INE91-130 C-169095 1040113 336148 6425028 Neogondolella sp.d. .N. indinefa (Kovacs 1983).ramifon elemenls LO INE91-131 C-166094 1WG113 335841 6424799 Melepolygnefhus? sp. MiddlPLaie Triassic. late LadiniaR 67 2 Carnian LO INE91-131-2 C-166093 1WGl13 335841 6424799 Melawfvonafhmso. i&Triassic. Carnian 4.5 2 L1 INE91-231 C-169632 1MGH3 333511 6430543 Mel=po&alhus ip. Lale Triassic, Carnian 5.08.0 2 Ll iNE91-235 C-166090 1WG113 333309 6431727 Melapl~gn~lhosnodosus(Hayashi1966). Neogwdolella indinale Lale Triassic. lale Carnian 4.55.5 2 (Kovacs 1963) L1 iNE91-235 C-166090 1WGl13 333309 6431727 Melapolygnalhussp.. Neccavilella?sp.. Neospalhodus? SP.. ramilorm 2 elmenls L1 JT191-59 C-169627 1MG113 331469 6431230 Neogondolella? sp. probably TriassLc 6.0 2 L1 JT191-61 C-169626 1MGll3 344695 6427643 Mefapolygnafhus sp..ranifom elements Lale Triassic, Cainian 5.0-5.5 2 uTSsl JT191-141 C-169830 104Gll3 322323 6405003 Mefapolygnalhus oodosus (Hayashi1966). ranifom elemenls Late Triassic.lale Carnian 5.0 2 TRIASSIC 1 mTc MGU6M96 C-166063 IWGIffi 357916 6353667 Neogondolells sp., ramitom elements Triassic? - 1 mTc DBR91-139-2 C-167945 1WGI12 323237 6403975 Neoslrepfognalhodus?sp., Hindeodus 6%. ramifom elwnenls Carbboniferous? - Early Permian 5.0 2 mTc DBR91-632 C-189624 1WGll3 329002 6404711 Neogondolella nepalensb (Kozur and Mosller 1976).Ellisonia sp. Early Triassic,Smilhian 5.5 1 mTc DBR91-632 C-169824 1WG113 329002 6404711 Neospalhodussp. d.N, pakjslanensis (Sweel1970). ramilorm element 1 mTc DBR91-671 C-169625 1WGl12 338266 64W656 Neogondolella exgc foliala (Bwlurov 1975). ramiform ekmenl MiddleTriasric, Ladinian 5.0 1 STlKlNE 1 IPSC DBR88-124-1 C-154278 1WG105 349625 639989 Neogondolella sp.. Neoslreplcgnalhodus cf. N. pquapsnsis (Behnken Early Permian. Artinskian 5.56.0 1 1975) IPSC DBR88-126-1 C-154280 1MG105 349154 6350206 Neoslreplognafhodus d.N. paquopansis (Behnken 1975) Early Permian. Artinskian 5.08.0 1 IPSC DBR88-164-1 c-154288 104Gl06 351416 6350416 Neoslreplognalhodus sp. Earty Permian, Artinskian 4.5.5.0 1 lPSC DBR88-164-2 C-154289 lWGlC6 351414 63W01 Neoslreptognafhodus? sp. EartyPermian 5.0 1 IPSC OBR88-166-2 c-154292 1WGIffi 351266 6350405 Hindsodussp.. ramiform elements Ca~oniferous-EarlyTriasslc 5.08.0 1 IPSC DBR88-167-1 C-154293 1WGIffi 351199 6350390 Neogondolslla sp.: Neosfreplognafhodursp..ramifon elemenk Early Permian, Artinskian 5.0-7.0 1 iPSC DBRW-168-1 c-154294 1WGIffi 351 149 6350384 Neogondolella sp.; Neoslreplognalhodus? sp. Early Permian 5.08.0 1 . IPSC DBR88-1693 c-154295 1WGIffi 351030 6350365 Neoslreplognalhodus sp.. ramifom elements Probably Early Permian 5.08.0 1 Y APPENDIX 3. Conlinued

UPS DBR88-246-1 C-159127 104Glffi 357894 6353908 Neogondolella sp.. ramform elemenls Permian 4.m.0 1 UPS DBR68-250-1 C-159129 IWGlffi 358474 6353463 Neogondolella cf phosphonensis (Youngquist. Hawley & Miller).Late Permian 8.0 1 UPS DBR88-251-1 C-159130 1WGlffi 358400 6353471 Hindecdus sp.: Neogondolellasp.. ramifom elementsPermian 8.0 1 UPS DBR88-252-1 C-159131 IWGlffi 358372 8353514 Hindeodussp.:Nsagandolellasp.. ramitom elemenlsPermianLate? 6.5-7.0 1 UPS DBRM-252-2 C-159132 IWGlffi 358379 6353513 Hindecdussp.: Neogondolella sp.. ramitom elements Late? Permian 6.5-7.0 1 IPSC DER84239 C-158935 1WGll2 339524 elemenls6401229 Ramiform Ordwiu'an - Triassic 5.5 1 1PSC MGU88198-1 C-159134 1WGlffi 350472 6350814 Ellisonla sp., Hindecdus sp.. Neogondolella sp.. Neoslreplognalhodus sp. Early Permian. Artinskian 4.5-5.5 1 lPSC MGU88199-1 C-159135 1WGIffi 350453 6350693 Elllsonia sp.. Hindecdus sp.. Neogondolella sp.. Neoslreplognalhodus sp. Early Permian, Artinskian 5.5.7.0 1 1PSC MGU68200-1 C-158906 1MGIffi 350409 635030 Indeterminate prductoid brachbpods. echinodermcolumnal. Carboniferous or Permian 5.0-5.5 1 1PSC MGU882W-1 C-159136 1WGiffi 350409 6350560 Hindeodussp.. amiformCarboniferous-EarlyTriassic elements 5.0-5.5 1 Ra miform elemenls IndeterminateIPSC MGU68-202-1 C-159138 elemenls1WGiffi 350351 6350343 Ramiform 5.0+ 1 IPSC MGU88203-1 C-159139 1WGIffi 350442 6350345 Neogondolella sp.. Neoslreplognalhcdussp..ramilonn elemenls Early Permian 5.06.0 1 mTc MGU8429 C-158920 1WG112 338434 6403213 Neogondolella sp., NeoSlreplcgnalhcdus?sp.. ramifomelments EarlyPermian. ?Artinskian 5.0 1 "CS" MGU64300-2 C-158947 1MG112 343960 6376764 Ramiform elemenls OrddWiciawTriaSsic 5.0 1

1PSC MGU64327 C-I66024 104G105 349204 6350695 Hindecdus sp. Early Carbonilerow~ Permian 5.5 1 lPSC MGU64337 C-168027 1WWffi 350188 6350474 Neogondolella sp.. Ellisonia sp., Neostreplognslhcdus sp. EariyPermian, Artinskian 5.5 1 UCSC MGU89-359-2 C-168037 1WG105Permian 343628 elemenls6357648 Ramiform - Triassic 5.0 1 "CSC MGU64.362-2 C-168040 1WG105 343537 6357594 Nsogondolella sp.. Diplognalhodus? sp. CarbmilerausLale - Permian 5.0 1 IPSC MGU89-376 C-168051 1WGlffi 354914 6350057 Neogondolella sp., Sweelognalhossp.. Ellisonia sp., raniform elements Permbn 4.06.0 1 IPSC MGU84377 C-166052 lWG1ffi 355094 6350052 Necgondol.?lla sp.. Sweelognalhus?sp., ramiform elemenlsPermian 5.0-7.0 1 IPSC MGU84378 C-168053 1WGIffi 355361 6350WO Neo~lreplognalhodussp. Early Permian. Artinskian 4.5-5.0 1 IPSC MGU89.363 C-166055 IWGiffi 358499 6353502 Ellisonla sp.. Hindecdussp.. Neogondolella sp.. rmilonn elements Late? Permian 7.0+ 1 IPSC MGU6963 C-158921 1WWl2 339188 6402477 Adelognalhos sp., ramifom elements Lale Carboniferous - Early Permian 4.5 1 ISaharbn) IPSC MGU6964 C-158923 1WGllZ 339087 6402542 Adefognalhussp..'Neoslreplognalhodus'sp..ramiformelements ArtinskianSakmarian. 7 Artinskian 4.5 1 IPSC MMC88-185-1 C-159113 1WGiffiIndeterminate 346956 6354862 Ramform elemenls 5.0-5.5 1 IPSC DBR91-227 C-167949 1WGll2 345997 6403031 Neoslreptognalhodus?sp. aH. N. pequopensis(BehnXen 1975) Early Permian, Artinskian 5.0-5.5 2 IPSC DBR91-227 C-167949 1WG112 345997 6403031 Neogondolella sp.d .N. idahoensis. ramiform elements 2 UCSV DER91493 C-189810 1WG113 324733 6426028 Neogondolella sp. indet. Probably Permian 6.0 2 IPSC DBR91-666 C-169622 1WW12 335416 6403201 plaIformfragment 7Carbanilerws-T~iasslc 5.56.0 2

Reference: 1. Orchard, M.J.. 1%. Geological Sulvey of Canada. Report nwnber MJOINw. 90 2. Orchard M.J., 1992. Geological Survey of Canada. Report nwnber OF-1992.26 Ministry of Employment and Investmen1

APPENDIX 4 BARREN CONODONT COLLECTIONS

MAP FIELDNTS GSC UTM zone w CODE NO. NO. MAP NORTHINGEASTING

SNHlNl GROUP uTSmv DBR85103-1 C-154271 1wwc6 3W103 %I57524 Ll CGR89-260-2 c-168008 1WGH 1 345571 6400883 Ll c-158949 1WGH2 340341 6399465 L2 C-168042 1ww12 353543 6377410 L1 ~. C-158925 1MW12 348323 €400898 u DBR89-156 c-156934 1ww11 349338 6369208 u DBR89-291 C-167911 1w11 355092 6378763 uTSmv MMCW-163-1 C-159109 1wW06 360688 6359191 vTSm MMC88-163-2 C-159110 1wwo6 360689 6359183 uTSrnv C-159111 1Mu06 360595 6359040 uTpm C-154270 1Mu06 358583 6354676 UTP MMC88-160-1 c-159108 1Wu06 360873 6359576 "TSSl CGR89-302 C-158950 104w12 340607 6399452 UTSS1 DBR894SE-3 c-168041 1ww12 352240 6402171 "TSSl CGR89-169 C-168003 104w12 351657 6389893 uTSs1 CGR89-172 C-168005 1wW12 351657 6389893 "TW DBR89-160 C-167913 1ww11 349517 6389094 "TSV CGR89-391 c-168043 1ww11 335917 6391964 "TSS2 CGR89-2% c-168006 1ww12 356984 6381096 uTSv C-167914 1WGIl2 349620 64W261 uTSS1 C-167917 1WG/12 351176 6401499 UTS C-159106 1WG106 356073 6357142 mTc C-168012 lCMGIl2 343101 6402251 "TSSl C-168013 104w12 344401 6402644 uTSs1 c-158937 104w12 342741 6401677 uTSSl C-189826 1WGl13 322954 6411474 mTc C-167945 104Gl13 323237 6403975 uTSv c-189809 104Gll3 324428 6422678 IPSC C-18SsM lMGH3 325715 6396977 UTSS DMU91-93 C-168077 104G113 326575 6413930 "TSV INE91-92 c-168098 104W13 330641 6414764 uTSrl 1NE91-229 C-189831 104W13 333856 6430863 "TSV DBR91-400 c-168089 104W13 335449 6415727 "TSSl DER91-185 C-167947 104G113 342895 6413535 IPSC JT191-80 C-189829 104Gll3 342904 6424881 IPSC INE91-182-3 c-168091 104W13 343055 6428199 UTSV INE91-3 c-1681w 104W13 348970 6416453

STlKlNE ASSEMBLAGE lPSc CGR89-275 C-168071 1MGH 1 343164 5402043 UCS CGR89-398-2 C-167919 1ww11 335462 6402326 "CS CGR89-398-3 C-167920 104Glll 335482 6402326 lPSc DBR8&010-2 c-154266 1MGm5 348608 6351666 UPS DBR88-024-1 C-154267 104W06 357507 6351702 IPSC DBR88-117-3 C-154274 104005 350625 6350300 IPSC DBR88-118-3 C-154275 1WG105 350901 6350357 IPSC DBR88-125-1 C-154279 104GIG5 349358 6350114 IPSc DBR85127-1 c-154281 104U05 348928 63%?48 IPSc DBR88-1251 c-154282 1W05 348671 6350220 Ipsa DBR88129-1 C-159133 1WC6 347956 6351246 IPSC DBR88-131-3 C-154283 104G105 348112 6351112 ipsa DBR88-132-1 c-154264 104Gm5 348010 6351148 IPS0 DBR85132-4 C-154285 1WG105 348032 6351146 IPSC DBR8E165-1 c-154290 1MG106 351348 6350409 IPSC DBR88-1661 C-154291 1WG106 351268 6350411 1st DBR88-1784 C-159102 104W05 345672 6352353 "CS? DBR€&179-1 C-159103 1WW05 345570 6352397 IPSC DBR88-332.5 C-159140 104W05 350514 6350320 IPSC DBR89-228 C-158935 104w12 336721 6400940 ucss MGU85Wl-1 C-154272 104G105 343659 6357535 1st MGU8B060-1 c-154296 104G105 340602 6357836 1st MGU88-061-1 C-154297 104GM5 340639 6357660 Ist MGU884X2-1...... c-154298 IMG~S 340639 6357586 1st MGU8B063-1 C-154299 1WG105 340613 6357470 1st MGU88-067-1 c.154m 104GD5 340618 6357169 bt MGU88-068-1 C-158901 104G105 340618 6357083 1st MGU88-130-1 C-159105 ~MGMS 341285 6356625 IPSC MGU88-201-1 C-159137 1MW06 350280 6350361 "CSS C-158928 1WG/12 340524 6381697 ucss MGU89-142 C-158930 1WG112 340555 6380961 ucss MGU89-201 C-158931 104w12 336440 6388157 IPSC MGU89-207-1 C-158932 1WGH2 336698 6389294 lPSc MGU89-207-2 C-mJ933 lWGH2 336698 6389294 British Columbia

IPSC MGU89-288 1WW05 342352 6373828 "CS" c-158947 1wG112 344ooo 6376764 "CS" c-158948 1WW12 344ooo 6376764 IPSC ...... C-168025 1WG105 349399 -12 IPSC MGU89-320 GI68026 1WG105 349ooo 63M993 IPSC MGU89-349 c-168028 1WG106 348651 6350874 IPSC MGU89-350 C-168030 1WWffi 348621 6350930 IPSC MGU89-352 C-168031 1WW05 348468 6351134 IPSC C-168032 1WW05 348370 6351229 IPSC c-168034 1WW05 348293 6351320 IPSC C-168035 1WW5 348559 6351559 IPSC C-168036 lWW05 34851 1 6351558 ucss 1WW05 343778 6357807 UCSS 1WW05 343574 6357618 UCSS C-158924 1WW12 338431 6385488 ucsv c-154258 104005 340820 6361353 "CS" C-154259 lWWO5 340908 6361445 ucsv ...... C-154260 1wG105 341115 6361418 IPSC MMC88WI C-154261 1WG106 352653 6347550 IPSC MMC-3 C-158916 1W06 354315 6347603 SIS MMC8W60-1 c-154264 1WWO5 340624 6357735 "CS? MMC88-989-1 C-154265 1WG105 346375 6349322 ucss MMC88-181-1 C-159112 1MGl06 346185 6354849 st MMC88-188-1 C-159114 1WW06 347072 6354478 IPSC C-159115 1MW06 347083 6354350 ucsv C-159116 IWW05 341883 6361269 "CSS C-159117 IWWG? 343031 6361417 IPSC C-167928 1WW05 346868 6348115 IPSC '2-167939 lWG105 347026 6347869 uTSmv C-167930 1MG106 360766 6358728 uTSmv C-167931 1WW06 360767 6358728 uTSs1 ...... GI67936 1wG112 329496 6403156 uTSs1 DER%-117 C-167938 1MG112 329381 6403081 uTSs1 DBR9C-124 C-167932 1WW12 328549 6403285 uTSs1 DER%-125 C-167933 1WG112 328587 6403282 uTSv DBR90144 C-167934 1WG106 359271 6355660 IPSC DBR91-129 C-167942 1WG113 322211 6403938 "CSC INE91-341-2 c-189833 1WG113 322331 6395934 VTSS DBR91643-2 C-189823 1WG113 322620 6413673 IPSC INE9149 c-168080 1WW13 322837 6403554 IPSC C-168081 1WGH3 322846 6403450 IPSC C-167943 IWGll3 323175 6402844 IPSC C-168092 1WW13 323629 6402593 "CS C-189807 1WW13 324350 6402940 uTSs c-189806 1WW13 324745 6427267 IPSC C-167946 1WGH3 324852 6403611 ICs" C-189805 1WGl13 324932 6429347 SI C-189821 1WGl13 326919 6420317 iTC rNE91-14 c-168099 1WGH3 327344 6402893 uTSsl DBR91-628 C-189820 1WG113 328397 €404303

References: Orchard. M.J. (1%): Geological SuNeyofCanada. Rewtinumber MJOINOV.90 Orchard. M.J. (1992): Geological Survey of Canada. Repti number OF-1992-1.

I40 Geological Survey Brnnch APPENDIX 5 RADIOLARIAN AGEDETERMINATIONS

IFIELD NTSGSC NO. UTM ZONE 09 AGE REF. juo. MAPNORTH EAST :STUHINI GROUP lDBR88-043-1 C154270 lWG06 358583 6354676 indeterminate 1 IDBR 916W C189826 IDBR916W 104G13 322958 6411698 Phanerozoic 2

lJnit mTc 1DBR90117 C167938 1WG12 6403081329381 TriaSSIC-LadinianMiddle 3 IDBR90139 C167944 104012 6404186323257 PhanelOzOiC 2 1DBR91-222 C167948 346614104G12 6403173 Phanerozoic 2 OBR91628 C189820 104G12328390 6404519 late Early Permian-Art,nskian to 2 Kungurian !XIKINE ASSEMBLAGE lrlGU88M)I-1104G05 C154272 6357535 343659 indeterminate 1

Fauna dercriptionr M auailuble upan requeu.

REFERENCES: I.Orclwd, MJ., 1990, Gcological Survey ofcanads, Repon number MJOMov. 90. i.Cordey,F., 1992.GcologicalSvrvcyofCnnada,RcponnumberFC-1992-2. 2. Cordey, F., pemnal communicalion. July 13. 1992.

Bullelin 95 141 Brifish Columbia

142 Geologicul Survey Branch Ministry ofEmplovment and Investment

APPENDIX 6 SAMPLES BARREN OF RADIOLARIA

FIELD GSC NTS UTM Zone 09 REF. NO. NO. MAP EAST NORTH

STUHlNl GROUP MMC86-158-3 C159107 1MG06 6359652360977 1 DER89247 C158937 1WG12 6401677342741 2

STlKlNE ASSEMBLAGE O BR88-171-1 C159101 OBR88-171-1 1WG05 54M01 6351266 1 D BR88-075-1 C158917 DBR88-075-1 1WG05 6372881340333 1 C GR84276 c168012 CGR84276 1WG11 6402251343101 2 CGR89288 C168013 1WG11 344401 Mo2M4 2 D BR6E133-2 C154287 DBR6E133-2 lMGO5 6351332 154781 1 MGU8&0Wl C154273 1WG05 6357140343752 1 D BR88024-2 C154266 DBR88024-2 1WG06 1 6351717 357512 OBR88-025-1 C154269 lWG06 1 6353807 357663 DBR88-242-1 C158918 1WGffi 1 6350367 359308 DBR88-245-1 C159126 1WG06 1 6353661 356029 D BR65246-1 C159127 DBR65246-1 1WG06 1 6353908 357694 C159126 1WG06 357636 6353958 1 DBR88-247-16353958 357636 1WG06 C159126

REFERENCES: I. Orchard. MJ.. 1990. Gmlogical SuneyofCanada. Rcwn numkr MJOMov. 90. 2. Cordey, F.. 1992. pemnal Communication.

13ulletin 95 143 Brirish Columbia Minisrry of Employmenr and lnveslmenl

APPENDIX 7 PALYNOMORF'H COLLECTIONS

MAP MAP FIELD GSC NTS UTM Zone09 AGE REF. NO. CODE NO. NO. MAP EAST NORTH

SUSTUT

c4 KTS DBR89-414 C167903 1WGl1 39925 6384925 early Paleocene 1

c1 KTS CGR8968 C167905 1WGl1 359040 6393772 indeterminate 1

c2 KTSr CGR89-128 C167906 104G12 360116 6393971 indeterminate 1

c3 KTS DBR84-268 C167901 1WGl1 347336 6385398 indeterminate 1

c5 KTS DBR90-25 C167921 lWGll 358264 6369001 indeterminate 2

C6 KTS DBR90-26 C167922 1WG11 358341 6388844 indeterminate 2

c7 KTS DBR90-27 C167923 lWGll 358351 6388796 indelerminate 2

C8 KTS DBR90-28 C167924 1WGll 353888 6392293 indeterminate 2

c9 KTS DBR90-29 C167925 1WGll 353872 639230 indeterminate 2

ClO KTS DBR90-30 C167926 lWG11 354065 6392360 indeterminate 2

c11 KTS DBR90-31 C167927 lWGll 353996 6392422 indeterminate 2

HAZELTON

c12 ImJHv DBR89-275 1 C167902indeterminate 1MGl16385285 347282

C13DBR89-424 IJHs C1679M 1 indeterminateIWGl1 6381410 354787

References: 1. Sweet. A.R.. 1989. Paleontology Division. ISPG. Calgary. Alberfa. Reportnumber AS-19896. 2. sweet. A.R.. 1990. Paleontology Division, ISPG. Calgary. Alberta. Reportnumber AS-90-08.

Bullelin 95 145 Brirish Colurnbio

~- 146 Geological Survey Branch APPENDIX 8 WHOLE-ROCK AND TRACE ELEMENT CHEMISTRY OFSTRATIFIED ROCKS

FIELD NO UTMNTSMAP UTMROCK MAP SiO, li02 AI,O, FerOd MnD MgO cao Na,O KzO zone 9 NORTHEAST CODECODE % % % % % % % % % DETECTION LIMITS: 0.01 0.01 0.01 0.01 0.010.01 0.01 0.01 0.01 ANALYTICALTECHNIQUE XRFllCPXRFllCP XRFIICP XRFllCP XRFllCP XRFllCP XRFIICP XRFllCP XRFllCP Unit Mb DER91495 104G13 337841 MW97 Mb BSLT 56.57 0.98 15.09 7.35 0.13 4.28 4.67 3.58 2.29 DBR91695-2.104G13 337841 "97 Mb ESLT 56.25 0.96 15.00 7.38 0.14 4.52 4.65 3.78 2.23 DBR91-6953 104G13 337841 6409497 Mb BSLT 56.14 1.01 15.02 7.50 0.13 4.63 4.52 3.93 2.06 Sloko Group: FLOWS andlor SILLS ~~~69.19~310.1~11 353015 6392471 TS DClT 64.13 0.43 16.29 4.44 0.17 0.61 2.51 5.35 2.61 DER69456 104Gll 351446 6392545 TSd BSLT 54.10 0.92 17.02 6.67 0.16 3.59 5.44 3.62 2.03 DER69459' 104Gll 351457 6392485 TSd RDCT 57.06 0.72 14.50 6.61 0.15 1.77 6.05 2.50 2.09 DBR69460' 104G11 351269 6391945 TSb TCAN 55.47 0.77 16.26 7.43 0.16 2.97 6.16 2.50 2.26 DBR69466 104G11 352432 6392360 TSb BSLT 59.54 0.70 16.74 6.36 0.17 2.25 5.39 3.69 2.26 DER69469 104Gll 352432 6392380 TSd FLOW 61.47 0.65 14.96 6.08 0.18 1 .86 4.16 3.90 2.62 DER89470 104Gll 352432 6392380 TSb TCAN 55.94 0.94 16.61 8.16 0.17 3.19 6.35 3.50 2.06 DBR69-471 104G11 352736 6392320 TSd ANDS 60.96 0.42 17.22 4.50 0.15 1.11 3.41 5.15 2.54 VOLCANICLASTIC ROCKS DER69467 1WGll 352272 6392237 TSd VCCB 60.29 0.62 16.93 5.63 0.17 2.10 4.18 3.90 2.82 Sustut Group: FLOWS andlor SILLS CGR69-200-2' 1MG12 353526 6395631 KTS ANDs 52.91 0.69 16.47 6.79 0.24 1 .83 7.12 3.91 1.79 CGR69-20D3 104G12 353526 6395831 KTS ANDs 54.62 0.90 17.02 6.22 0.12 3.36 6.04 3.29 1.96 VOLCANICLASTIC ROCKS CGR69-200-1104G12 353526 6395631 KTS TUFF 74.31 0.15 12.75 1.20 0.02 0.42 0.76 0.92 6.61 Hazelton Group: FLOWS andlor SILLS C G R69-217 104G12CGR69-217 355389 6376236 hJHv ANDS 54.10 0.72 17.74 8.32 0.14 3.41 3.69 5.96 0.64 CGR69-227 104G12 356604 6361456 hJHv ANDS 56.74 0.75 16.53 7.90 0.15 3.16 5.99 3.11 2.03 CGR69-237 l04G12 356002 6380736 hJHv FLOW 56.96 0.79 16.90 7.33 0.17 3.53 7.23 2.70 2.17 C G R89-30 104G11CGR89-30 367720 6386518 hJHv ANOS 51.74 1.10 17.03 6.91 0.16 4.13 7.92 3.35 1.65 CGR69439 104G11 348412 6387905 hJHv ANDs 56.35 0.80 16.89 7 39 0.15 2.96 6.93 3.09 1.96 CGR69467 104G12 355236 6360092 hJHv ANDS 52.02 0.69 16.42 8.66 0.16 3.99 9.05 2.71 1.21 CGR8946 1MG11 363364 6390305 hJHv FPPP 56.23 0.84 16.93 7.91 0.12 2.10 5.76 2.91 2.18 CGR89-511 104G11 354635 6386287 hJHv ANDS 53.1 1 1.02 16.38 8.91 0,24 5.04 4.11 5.71 0.67 OER69-155' 104G11 349364 6389572 hJHv ANDS 50.56 0.93 16.84 7.96 0.15 2.96 5.92 4.08 1.94 DER69-303' 104G11 354320 6379905 ImJHd RYLT 70.73 0.23 14.22 3.06 0.03 125 1.27 1.79 3.66 OBR69-377 104G11 346341 6387506 hJHv RYLT 71.60 0.24 14.09 3.37 0.01 0.20 0.24 3.40 4.60 DER89430 104G11 354407 6361909 ImJHb ESLT 49.53 0.64 16.00 8.56 0.14 5.55 11.23 2.01 1.17 DBR69432' 104Gll 353476 6361935 lmJHb BSLT 52.54 1.02 16.24 6.26 0.16 4.62 6.98 2.93 1.82 DBR69435 104G11 353139 6362257 hJHv ANOS 64.75 0.59 15.47 3.67 0.10 0.76 2.55 4.06 4.09 OBR90-151' 104Gll 354265 6381506 lmHd RYLT 47.10 1.05 18.46 6.60 0.14 4.76 5.59 5.05 2.02 DER90-162' 104G11 355655 6377046 lmHv ANDS 47.68 1.04 17.70 9.26 0.19 2.96 11.10 2.26 0.60 DBR91-714' lWG12 348865 638599 lmHv ANDS 61.25 0.60 15.57 5.86 0.10 1.01 3.46 3.11 2.63 DBR91-715' 104G12 346912 6386070 hH" ANDS 50.12 0.92 16.75 10.95 0.17 2.89 5.03 6.96 0.51 DER91-716 104G12 348917 6386091 lmHv ANDS 46.56 0.93 17.66 10.27 0.19 3.66 8.49 3.41 2.56 DBR91-719' 104G12 348639 6386112 hHb BSLT 47.74 0.89 16.31 6.17 0.31 3.47 7.57 6.17 0.45 DBR91-720 104G12 348626 6386148 hHb BSLT 51.64 0.97 16.60 10.88 0.16 3.03 3.82 7.51 0.13 f FIELD NO UTM UTMNTSMAP ROCK MAP K.OINa.0 LO1 PXO. OX-SUM Fe.0. FeO S CO, Ni Mo Zn zam, 9 EAST NORTH CODE CODE RaUo % % % % % % % PP ppm PP DETECTION LIMITS: 0.01 0.01 5 8 2 ANALYTICAL TECHNICIUE XRFllCPXRFllCPXRFllCP cdc. TIT AAS AAS AAS Unit Mb DBR91-695 l04G13 337841 €409497 Mb ESLT 0.64 0.31 3.79 99.24 5.05 2.07 DBR91-695.2'104G13 337841 6409497 Mb BSLT 0.59 0.31 4.17 99.41 4.59 2.51 0BR91-695.3104G13 337841 64W497 Mb BSLT 0.52 0.32 3.85 99.1 1 4.19 2.97 Sloko Group: FLOWS andlor SILLS DBR89-1983 104G11 353015 6392471 TS DCiT 0.49 0.24 2.22 99.20 3.58 0.79 0.01 0.40 91 DBR89-458 lWG11 351448 6392545 TSd BSLT 0.53 0.36 2.95 99.08 3.97 4.23 0.01 0.90 97 DBR89-459' 104Gll 351457 6392485 TSd ROCT 0.84 0.24 8.24 99.93 4.53 1.87 0.01 4.52 89 DBR89-460' 104Gll 351269 6391945 TSb TCAN 0.91 0.27 5.23 99.52 3.24 3.77 0.01 2.66 84 DBR89-468 104Gll 352432 6392380 TSb BSLT 0.58 0.23 2.22 99.75 4.45 1.72 0.01 0.14 81 DBR89-469 104G11 352432 6392380 TSd FLOW 0.67 0.21 3.30 75 99.45 5.52 0.50 0.01 0.65 DBR89-470 104Gl1 352432 6392380 TSb TCAN 0.59 0.26 1.90 99.28 4.17 3.59 0.01 0.14 89 DBR89-471 104Gll 352738 6392320 TSd ANDs 0.49 0.25 3.59 99.30 3.14 1.22 0.01 0.14 95 VOLCANICIASTIC ROCKS DB R89 -467 104G11DBR89-467 352272 6392237 TSd VCCB 0.72 0.23 2.58 99.45 3.95 1.51 0.01 0.47 85 SuStut Group: FLOWS andlor SILLS CGR89-2002' lMG12 353526 6395831 KTS ANOS 0.46 0.26 5.49 86 99.70 4.32 4.02 0.01 3.19 CGR89-2003 104G12 353528 6395831 KTS ANOS 0.60 0.27 3.70 99.70 5.19 2.73 0.01 0.36 89 VOLCANICIASTIC ROCKS CGR69-2001 104G12 353526 6395831 KTS TUFF 7.40 0.03 2.81 29 100.18 0.80 0.36 0.01 0.14 Harelton Group:

FLOWS~~ andlor ~ SILLS CGR89-217 1MG12 355389 6378238 hJHv ANOS 0.11 0.26 3.92 99.10 6.16 1.94 0.01 1.23 70 CGR89-227 104G12 356604 6381458 hJHv ANDs 0.65 0.16 3.26 99.78 4.47 3.w 0.01 1.45 70 CGR89-237 104G12 356002 6380736 hJHv FLOW 0.80 0.20 1.67 99.67 3.65 3.31 0.01 0.14 70 CGR89-30 104G11 367720 6388518 hJHv ANDs 0.55 0.39 2.77 99.35 5.64 2.94 0.01 0.77 69 CGR89-439 104G11 348412 6387905 hJHv ANOS 0.64 0.24 2.84 99.62 4.43 2.66 0.01 1.44 71 CGR89-467 104G12 355236 6380092 hJHv ANOS 0.45 0.17 2.31 99.41 4.03 4.17 0.01 0.79 71 CGR89-48 104G11 363364 6390305 hJHv FPPP 0.75 0.18 2.38 99.34 3.92 3.59 0.01 0.51 66 CGR89-511 104G11 354835 6386287 hJHv ANOS 0.12 0.28 3.62 99.09 5.23 3.31 0.01 1.37 130 DBR89-15s 104G11 349364 6369572 hJHv ANDs 0.48 0.45 7.36 99.17 6.62 1.22 0.01 1.08 93 DBR89-303' 104G11 354320 8379905 hJHd RYLT 2.06 0.03 3.57 99.86 1.46 1.44 0.01 1 .01 52 DBR89-377 1fflG11 348341 6387506 hJHv RYLT 1.41 0.02 1.39 99.56 2.97 0.36 0.01 0.14 44 OBR89-430 104Gll 354407 6381909 lmJHb BSLT 0.58 0.15 4.02 99.22 2.68 5.31 0.01 2.02 59 DBR89-432' 104Gll 353476 6381935 ImJHb BSLT 0.62 0.27 4.60 99.44 3.31 4.45 0.01 2.06 72 DER89-435 104Gll 353139 6382257 hJHv ANDs 1.01 0.17 3.55 99.96 3.24 0.57 0.01 1.91 44 DER%-151' 104011 354265 6381506 lmHd RYLT 0.40 0.24 7.49 98.72 1.27 4.97 0.21 3.86 DER90-162. 104G11 355855 6377046 lmHv ANOS 0.26 0.20 5.71 98.72 2.78 5.84 0.01 3.44 DBR91-714' 104G12 348865 6385994 lmHv ANDs 0.91 0.15 5.61 99.59 5.15 0.66 DBR91-715' 104G12 348912 6386070 lmHv ANDS 0.07 0.21 4.75 99.26 9.28 1.50 OER91-716 104G12 348917 6386091 lmHv ANDs 0.76 0.23 3.02 99.04 6.60 3.30 DBR91-719' 104G12 348639 6386112 hHb BSLT 0.07 0.20 8.19 99.47 4.05 3.70 DER91-720 104G12 348628 6386148 lmHb BSLT 0.02 0.20 4.07 99.01 8.03 2.56 FIELD NO NTSMAP UTM UTM MAP ROCK Cr Ba ST Rb Zr Y Nb Ta V La Sn Th U zone 9 NORTHEASTCODE CODE ppmppm PP ppmppm PP PP ppmppm ppm PP PP~PP~ DETECTION UMITS: 10 10 5 10 20 10 5 NA 5 15 NANA NA ANALYTICAL TECHNIQUE XRFXRFXRF XRF XRF XRF XRF XRF XRF XRF XRFXRFXRF Ilni9.. . . MIX. . . . . DBR91-695 104G13 337841 6409497 Mb BSLT 113 531 54 171 21 8 45 DBR91-6952' 1MG13 337841 6409497 Mb BSLT 108 469 50 171 23 9 <15 DBR91-6953 lWG13 337841 6409497 Mb BSLT 105 431 42 171 20 9 45 Sloko Group: FLOWS andlor SILLS DBR89-19a31MG11 353015 6392471 TS DCIT 5 1611 405 45 166 25 7 44 25 DBR89-458 1MGl1 351448 6392545 TSd BSLT 15 1418 894 35 115 28 6 154 30 DBR89-459' 1MG11 351457 6392485 TSd RDCT 14 884 282 48 117 24 7 133 19 DBR89-460. lMG11 351269 6391945 TSb TCAN 16 1368 831 33 128 26 5 145 20 DER89488 lMG11 352432 6392380 TSb BSLT 21 1471 594 34 153 27 6 116 27 DBR89-469 104Gll 352432 6392380 TSd FLOW 23 1868 585 48 135 27 9 106 16 DBR89-470 IMGll 352432 6392380 TSb TCAN 24 1245 587 39 141 27 8 180 22 DBR89-471 WGll 352738 6392320 TSd ANDs 4 1602 5w 42 181 26 8 34 29 VOLCANlCLASTlC ROCKS DBR89-467 1MGl1 352272 6392237 TSd VCCB 12 1709 680 44 168 29 8 93 20 Suslul Group: FLOWS andlor SILLS CGR89-20@2' 1MG12 353526 6395831 KTS ANDs 18 1183 396 28 123 28 11 172 20 CGR89-20M 1MG12 353526 6395831 KTS ANDs 19 1173 571 36 127 30 9 171 11 VOLCANlCLASTlC ROCKS CGR89-20Dl 1MG12 353526 6395831 KTS TUFF 4 1157 72 121 131 22 13 9 33 Hazelton Group: FLOWS andlor SILLS CGR89-217 1MG12 355389 6378238 hJHv ANOS 20 447 783 15 82 24 5 183 8 17 C15 CGR89-227 104G12 356604 6381456 hJHv ANDs 23 1095 406 37 118 26 7 183 21 45 <15 <15 CGR89-237 1MG12 356002 6380735 hJHv FLOW 22 1015 430 49 127 25 11 198 16 c15 e15 c15 CGR89-30 1MG11 357720 6388518 hJHv ANDs 44 1109 587 30 140 30 11 240 25 C15 <15 <15 CGR89-439 1MGll 348412 6387905 hJHv ANDs 23 1091 465 41 131 26 7 178 19 17 <15 <15 CGR89-467 1MG12 355236 6380092 hJHv ANDs 16 689 406 24 83 22 6 196 18 45 <15 d5 CGR89-48 lWGll 363364 6390305 hJHv FPPP 15 1127 404 42 109 22 6 183 20 cl5 c15 45 CGR69-511 1WGll 354835 6386287 hJHv ANDs 100 401 361 19 143 27 9 198 22 45 ~1545 DBR89-155' 104Gll 349364 6389572 hJHv ANDs 19 391 502 40 200 29 13 192 30 DBR89-303' 1MGll 354320 6379905 hJHd RYLT 4 1030 178 107 284 30 15 2 31 DBR89-377 lWG11 348341 6387506 hJH" RYLT 4 2539 144 101 278 35 12 20 42 DBR89-430 1MG11 354407 6381909 lmJHb BSLT 158 455 307 22 87 27 8 213 17 DBR89-432' 1MG11 353476 6381935 lmJHb BSLT 71 811 444 33 145 27 8 185 18 DBR89-435 1MGll 353139 6362257 hJHv ANDs 6 1106 153 111 258 31 11 49 18 DBRW-151' lMG11 354285 6381506 lmHd RYLT 22 1129 569 10 131 27 7 234 25 DBRW-162' 1MG11 355655 6377046 hlH" ANDs 35 473 497 10 71 21 5 306 15 DBR91-714' 1MG12 348865 6385994 hH" ANDs

C GR 69-229 104G12CGR69-229 353793 6361361 hJHv CLTF 51.99 0.96 17.89 9.15 0.18 3.83 7.09 4.15 0.49 Sfuhinl Group: FLOWS andor SILLS C GR 69-IO 104G11CGR69-IO 350344 6391596 uTSv FLOW 49.27 0.91 13.01 11.16 0.21 8.17 9.97 3.27 1.39 C GR 89-163 104G11CGR89-163 341342 6391774 uTSv BSLT 46.74 0.74 12.33 10.63 0.16 6.55 11.86 1 .90 2.23 CGR89-163DUf 1WG11 341342 6391774 uTSv BSLT 46.68 0.74 12.33 10.78 0.16 8.56 1185 1.95 2.26 CGR69-264 104G11 345426 6400750 uTSvb BSLT 48.71 0.82 14.42 9.38 0.17 6.61 10.40 3.46 0.69 CGR89.266 104G11 345664 MOM69 UTSVP FLOW 48.35 0.86 13.82 10.26 0.19 6.76 9.05 2.74 3.15 CGR89-335 104G12 352292 6376373 uTSvb BSLT 46.75 0.65 9.76 10.62 0.37 10.76 14.39 1.11 0.57 CGR89-533 104G12 340089 6393659 uTSv BSLT 46.26 0.70 10.48 11.86 0.22 11.17 13.10 1.63 0.94 CGR69-554 104G12 345251 6396216 uTSv ANDS 46.1 1 1.18 16.34 11.37 0.25 4.90 7.43 3.60 2.27 CGR69-563 104G12 346606 6396233 uTSv BSLT 49.00 1.54 15.09 13.10 0.25 3.68 6.70 4.67 0.69 DBR69-281 104Gll 346610 6384970 UTSV FLOW 47.29 0.72 10.42 11.29 0.21 12.18 11.96 2.w 0.77 DER69-370 lWG12 344967 6392423 uTSvb ESLT 46.16 0.77 11.92 11.31 0.20 9.W 13.84 1.73 0.95 DER91-535 1MG13 338286 6430030 UT" BSLT 48.37 0.64 10.97 10.80 0.19 13.21 11.26 1.73 0.77 DER91-581' 1WG13 351503 64 18008 UTV BSLT 43.26 1.17 16.08 12.69 0.20 3.74 6.04 3.30 0.34 DEW-601 104G13 351704 E421915 UT" BSLT 50.95 1.07 17.46 10.42 0.18 4.12 6.97 3.04 0.76 DBR91-703 104G13 335493 6396746 "T" BSLT 50.24 0.61 13.64 9.67 0.15 7.77 6.70 2.51 2.77 JT191-53 104G13 333675 6430064 "T" ANDS 46.61 0.97 16.91 10.54 0.23 5.89 10.46 2.74 1.06 MGU88-176 104G06 360496 6369172 uTv ANDS 50.71 0.96 17.04 9.52 0.20 5.25 10.47 2.16 2.34 M GU 89.254 104G12MGU89.254 331650 6392506 UT" BSLT 54.09 1.w 16.30 9.56 0.16 3.59 7.95 2.24 1.77 MGU69.267 1WG12 329571 6392392 UT" ESLT 47.27 1.m 17.60 10.76 0.21 5.21 6.86 4.w 3.56 MGU69.270-1104G12 329185 6391797 UT" BSLT 49.34 0.63 13.85 10.60 0.20 7.31 9.17 2.23 3.36 MMC68-291' 104Gffi 353295 6356073 UT" BSLT 49.63 0.64 15.07 9.86 0.18 6.74 9.25 1.73 4.23 VOLCANICIASTIC ROCKS M M C68-263 104G06MMC68-263 357110 6357696 UT" TUFF 65.53 0.57 14.83 6.09 0.17 1.79 3.36 3.17 1.68 C GR 89-387 104G11CGR89-387 335509 6392668 UTSY LPTF 48.39 0.69 11.96 11.48 0.22 8.39 12.44 2.65 0.76 C GR 69-541 104G12CGR69-541 338624 6394075 uTSv LPTF 46.01 0.83 9.95 11.50 0.21 11.53 11.62 2.62 0.53 CGR69-541DUf104G12 338624 6394075 uTSv LPTF 46.06 0.63 9.91 11.49 0.21 11.62 11.63 2.47 0.52 DER69-382 104G12 333347 6395624 uTSvf TUFF 77.98 0.21 9.87 3.09 0.64 1.50 1.73 3.14 0.34 CGR69-477-1104G12 348953 6376500 uTSv VCCB 48.50 1.13 13.43 11.55 0.20 6.62 9.97 3.10 1.02 CGR89-550 lMG12 344435 6396670 uTSv VCCB 47.96 0.60 13.17 10.75 0.22 6,82 9.56 3.37 2.24 M M C86-16 104G06MMC86-16 361361 6357644 UTS VCCB 46.26 0.71 12.66 10.67 0.21 9.35 11.72 2.36 2.43 ~~ FIELD NTSMAP UTM UTM Fe,O,MAPOX-SUM ROCK LO1 P,O.KIOINa,O FeO S CO, Ni Mo Zn zone 9 CODENORTHCODEEAST RaUo x % x % x % K PW ppm ppn DETECTION LIMITS 0.01 0.01 5 8 2 ANALYTICAL TECHNIQUE: XRFllCP XRFllCP XRFIICP C~C. TIT AAS AAS AAS VOLCANICLASTIC ROCKS CG R89-229 104G12CGR89-229 356793 6381361 hJHv0.33 CLTF 0.12 3.36 99.44 6.59 2.30 0.01 1.05 83 Stuhinl Group: FLOWS andlor SILLS CGR89-10 lWGll 350344 6391596 "TS" 0.31 FLOW 0.43 1.84 99.51 5.66 4.95 0.01 0.14 93 CGR89-183 104Gll 341342 6391774 "TS" BSLT 1.17 0.43 3.38 99.17 4.47 5.72 0.03 0.14 74 CGR89-183DUf lWGll 341342 6391774 "TS" BSLT 1.16 0.43 3.38 99.34 4.40 5.74 0.03 0.14 82 CGR89-264 1WG11 345426 €400750 uTSvb BSLT 0.26 0.27 3.82 99.17 3.70 5.11 0.01 0.54 79 CGR89-268 104Gll 345584 64ChX69 uTSvp0.47 FLOW 1.15 3.58 99.25 5.54 4.25 0.02 1.w 74 CGR89-335 1WG12 352292 6376373 uTSvb BSLT 0.51 0.23 4.06 99.47 4.66 5.54 0.01 1.69 181 CGR89-533 1WG12 340089 6393659 "TS" BSLT 0.51 0.26 2.45 99.29 6.45 4.89 0.01 0.14 87 CGR89-554 1WG12 345251 6396216 "TS" ANDS 0.63 0.64 3.18 99.27 4.57 6.12 0.02 0.72 109 CGR89-553 104G12 346606 6396233 "TS" BSLT 0.14 0.70 3.41 99.03 5.42 6.91 0.36 0.14 125 OBR89-281 1C4GlI 346810 6384970 "TS" FLOW 0.39 0.14 2.14 99.12 3.61 6.91 0.02 0.29 80 DBR89-370 1WG12 344967 6392423 "TSVb BSLT 0.55 0.45 3.05 99.38 2.30 8.11 0.01 0.14 74 DBR91-535 1WG13 338286 6430030 "T" BSLT 0.45 0.19 1.49 99.64 1.71 8.17 OBR91-581' 1WG13 351503 84 18008 UT" BSLT 0.10 0.41 7.47 99.50 4.11 7.71 OBR91-601 104G13 351704 6421915 "T" BSLT 0.25 0.18 2.18 99.31 5.03 4.84 DBR91-703 104G13 335493 6398746 UT" BSLT 1.10 0.29 2.39 99.14 3.60 5.45 JT191-53 l04G13 333875 6430064 UT" 0.15 ANOS 0.39 1.71 99.31 1.62 8.01 MGU88-176 1WGC6 360496 6369172 UT" 0.32 ANDs 1.08 0.96 99.95 1.92 6.84 0.06 0.15 26 8 MGU89254 104G12 331650 6392506 UT" BSLT 0.79 0.22 2.30 99.24 3.83 5.17 0.01 0.33 99 MGU89267 104G12 329571 6392392 UT" OSLT 0.89 0.65 1.91 99.23 4.30 5.81 0.01 0.29 83 MGU89270-1 104G12 329185 6391797 "TU BSLT 1.51 0.53 1.90 59.32 2.31 7.46 0.01 0.14 72 MMC88-291' 1WG06 356295 6356073 UT" BSLT 2.45 0.31 2.27 100.11 3.84 5.42 0.01 0.15 44 8 VOLCANICLASTIC ROCKS MMC88-283 1WG06 357110 6357695 UT" TUFF 0.59 0.09 2.34 99.80 4.19 1.71 0.01 0.49 4 8 CGR89-387 104G11 335509 6392688 "TS" LPTF 0.27 0.24 3.66 99.28 4.96 5.67 0.01 0.91 80 CGR89-541 1WG12 338824 6394075 "TS" LPTF 0.20 0.21 4.48 99.69 4.39 6.40 0.01 1.23 81 CGR89-541DUI 104G12 338824 6394075 "TS" LPTF 0.21 0.20 4.47 99.61 4.78 6.04 0.01 1.30 79 DBR89-362 104G12 338047 6395824 uTSvf TUFF 0.11 0.07 1.98 99.75 1.01 1.87 0.09 0.32 50 CGR89-477-1104G12 348953 6376500 "TS" VCCB 0.33 0.25 1.42 99.19 4.84 6.04 0.01 0.14 49 CGR89-550 1MG12 w435 6395870 "TS" VCCB 0.86 0.26 4.20 99.37 4.75 5.40 0.02 1.52 87 MMC88-18 104G06 361381 6357644 "TS VCCB 1.03 0.30 0.97 99.84 2.36 7.48 0 01 0.15 102 6 FIELDNTSMAPUTM NO MAP UTM ROCK Cr Ba Sr Rb Zr Y Nb Ta V La Sn Th U zone 9 NORTHEAST CODE CODE ppm ppm ppm ppm PP ppm PP ppm PP ppm PP ppm ppm

D ETE CTION LIMITS:DETECTION~~~~~ ~~ ~~ ~ 10 10 5 10 20 10 5 NANA 5 NA 15 NA ANALYTICAL TECHNIQUE XRFXRFXRF XRF XRF XRF XRFXRFXRF XRFXRFXRF XRF VOLCANICUSTIC ROCKS CGR89-229 1MG12 356793 6381381 hJHv CLTF 31 373 878 11 108 25 7 258 26 15 4545 Sluhlnl Group: FLOWS andlor SILLS CGR89-10 1WG11 350344 6391596 uTSv FLOW 229 732 507 20 54 15 6 302 19 C GR 89-183 104G11CGR89-183 341342 8391774 uTSv BSLT 279 499 691 40 51 20 5 282 24 CGR89-183DUF 104Gll 341342 6391774 "TS" BSLT 279 495 685 45 50 17 8 276 18 CGR89-284 104G11 345428 8400750 uTSvb BSLT 192 487 617 20 52 21 3 276 14 CGR89-268 104Gll 345684 €400469 UTSVP FLOW 156 976 504 72 74 21 5 293 21 CGR89-335 104G12 352292 6376373 uTSvb BSLT 463 307 530 10 37 14 5 273 16 CGR89-533 104G12 340069 8393659 uTSv BSLT 468 411 943 17 48 18 4 297 18 CGR89-554 104G12 345251 6396216 UTSV ANDS 47 1342 762 32 72 25 5 404 14 CGR69-563 104G12 346606 6396233 uTSv BSLT 34 407 675 14 115 40 6 398 15 D BR 89-281 104G11DBR89-281 348810 6384970 uTSv FLOW 439 488 226 13 38 14 5 304 19 DBR89-370 104G12 361967 8392423 uTSvb BSLT 347 221 442 19 49 16 4 294 27 DBR91-535 104G13 338286 8430030 UT" BSLT 607 299 16 38 14 5 <15 DBR91-581' 104G13 351503 6418008 UT" BSLT

FIELD NO NTSMAP UTM UTM ROCK MAP Cr Ba Sr Rb Zr Y Nb Ta V Lb Sn lh U Zone9CODE CODENORTH EAST pprn ppm PPI ppm PW ppm PW ppm PW ppmppm DETECTION LIMITS: 10 10 5 10 20 10 5 NA 5 NA15 NA NA ANALYTICALTECHNIQUE XRFXRF XRF XRFXRF XRF XRFXRF XRF SEDIMENTARY ROCKS MGU69-222 1WG12 329405 6388264 ST7 SLST 456 224 345 32 46 17 7 284 24 M GU 89-227 1WG12 329698 6366729329698MGU89-227 1WG12 ST? SLST 114 1104 757 E4 79 24 6 281 19 .. M GU 69.215 104G12 332770104G12MGU69.215 6387261 31PSmI ANOS 167 338 15 149 40 7 200 8 MGU89-237’ 1MG12 333581 6390262 ST7 ESLT 561 261 265 22 52 17 6 263 31 MGU89-239104G12 33W8 634x)M ST? BSLT 274 377 188 21 31 15 6 256 11 Stiklne Assemblage: FLOWS andlor SILLS DBR91-360-23244511WG12 6402675 133ST ESLT 530 14 263 32 63 <15 DflR91-360-3 1MG12 324451 6402875 122ST ESLT 314 34 286 31 62 45 MGU69-264 1MG12 342586 6373599 ST ANOS 6 439 330 62 488 36 136 9 79 MGU89291‘104012 342430 6374251 ST ASLT 19.. 35 408 4 471 72 22 147 35 MGU89-297 1MG12 343572 6375215 ST89 1 ESLT 146 478 36 343 55 65 210 91 MGU89-303’ 1WG05 342233 6371247 442ST BSLT 562 426 15 71 24 5 375 22 M GU 69-307’ 104G05 341765MGU69-307’104G05 6371397 ST BSLT 43 869 571 19 134 35 9 138 35 MGU69-314 1WG05 341266 6371566 ST BSLT 228 1102 575 24 116 26 4 211 27 MGU69-319’ 1WG12 340697 6371614 261ST ESLT 735 392 32 94 25 7 249 25

Notes: = altered nav sampler lhal exhibil at least one of the following criteria:LO1 z -4%. C02> 2%. or K,O I Na,O 5 2 Alleralion was no1 evaluated for the pyroclarlic,valcanicl~~lic0, sedimentary samples. Abbrevlatiom: ESLT = baran. DClT = dadle. RDCT = rhycdacile. RYLT- myolile, ANDs = andesile. TCAN = lrachyanderile, FPPP = polassiun feldspar-plagioclase porphyrilic. CLTF= cryslal luff. LPTF = lapilli luff. VCCB E volcaniclaslic breccia. ~ I54 Geological Survey Branch APPENDIX 9

FILTERING OF GEOCHEMICAL DATA:

Geochemical data were screened for alteration priorto inclusion on discrimination plots. Only analyses from flows of andesite, basaltand dacite were plotted. Most suitesigroups contain pyroclasticor volcaniclastic units which wcrc not plotted. Thcir chemistryis listed in Appendix 8 together with geochemical results for the entire volcanic spccimen collcction. Mctamorphic facics ranges from zeolite to greenschist grade, therefore modcrate mobilityof large ion elements is cxpected.

Samples were rejectcdbased on any one ofthrce parametcn:

I) K20/Na20 greater than 2, eliminatcs hydratcd and potassic-altcred samples. High-potassium rocks, such as shoshonites, do not exhibit K20Ma20 ratios of greater than 2, thcrcfore, this is considered to be an appropriate limiting parameter.

2) Loss on ignition (LOI) grcatcr than4 wt.%, eliminatcs oxidizcd and carbonate-altered samples.

3) CO2 contcnt greater than 2 wt.%, also climinatcs cxccssivcly carbonate-altered samples British Columbia

156 Geological Survey Branch APPENDIX IO PETROGRAPHIC NOTES

S AM PLE NO UTM NO SAMPLE Zn 09 METAMORPHICLITHOLOGY METAMORPHIC N OR TH ASSEMBLAGE GRADE ASSEMBLAGE EAST NORTH

!$TIKINE ASSEMBLAGE: IJER91 - 501IJER91- 325286 6428982 chloritic phyllite vnlet: ep. chl. qtz.PY: xtls: greenschist

:STUHINI GROUP OGR8S 322 349932 6378251 pyx plag phyric bas ep. alb. act. qtz greenschist 'CGR8S 325 349786 6378452 amyg 01 pyx Plag phyric bas amyg: alb. ep. chl. cat greenschist 'ZGR89- 10 350344 6391596 (01) PYX Plag phyric bas vnls: ep. chi. qk. acl greenschist CGR88 183 341342 6391774 bsllic XU lith laplash luff matrix and1 vnlt: ze zeite CGR8S 262 345980 6400980 (ol?) pyx plag phyric bas vnn: pr. alb. chl. ze(?) tranrilional CGR8S 264 345426 6400750 bsltic (01-pyx-plag phyric) x11 matrix: calc. Chl. alb(?) transitional CGR88 268 345684 640C469 amyg pyx plag phyric bas amygs: Le. calc. chi. zeile CGR8S 335 352292 6376373 ep amphibolite (metabas. matrix and1 xtls: amph uppergreenschist CGR88 380 336800 6393778 bsltic x11 lilh lap tuff matrix: alb. calc. amph(?) greenschist CGR8S 387 335509 6392688 pyx-rich bsllic xll lith laplash malrix: ep. Chl. calc. pp. transitional CGR89-407-1 348313 6379142 amyg 01 Plag pyx bas amyg: ep. alb. Chi. amph. greenschist CGR8S 407-3 348313 6379142 amyg plag wx phyric bas amygs:ep. alb: vnns: calc greenschist CGR8S 408 348342 6379389 amyg pyx plag phyric bas amygs and1 matrix: alb. act. greenschist CGR8S 477-1 348953 6376500 uralilized pyx phyric bas vnlts: act alb. qu: uralifized greenschist CGR~S n1 338824 6394075 bsllic XU lilh laplash tuff vnlls: Calc. chl. ep; matrix: transmnal CGRBS 550 344435 6396670 pyx-rich volc brx or xu lilh luff matrix and1 amygs: calc. zeone CGR8S 551 344783 6396452 bsllic XU Iilh lap tuff-bn matrix: ,?e (wairakile?) zeolile CGR8S 554 345251 6398216 OK?) pyx plag phyric bas vnlts: cak. Chl. ep. ze(?) ZeMite CGR8S 563 346606 6396233 pyx plag phyric bsltic andt. vnk: calc. qtr. CL(?): greenschist DER8S 127 snag 6402165 amyg 01. pyx, plag phyric bas amyg and vnll: ze zeolile DER8S 316 353385 6381112 amyg pyx(?) ol(?) plag phyric amyg: Chl. qtz. calc; vnlt: transitional DER8S 445 350960 6393215 amyg 01 pyx plag phyricbar arnyg: ep. qtz. Chl. calc. alb greenschist DER88 126A 355547 6402150 amyg pyx (CPYX and OPYX?) amygs: Chl. calc. pp(?) P"PP DER8S 281 346810 6384970 altered pyx-rich melabas matrix: act. cab. ep. alb, greenschist DEWS 370 344967 6392423 bsltic lith xtl aSNlap tuff matrix ad. alb. calc. chl greenschist MGU8S 157 359608 6375918 lith x11 (plag pyx) laplashtuff matrix:chl. act transilional MGU89- 73-1 359468 6378210 pyx. plag rich metabas vnlls: Chl. cab. ep: amygs: greenschist CGR8S 210 355698 6376866 meta-andit amyg: ep. chl. alb. qtz greenschist CGR89- 312 353029 6377225 x11 lilh lap luff-bn matrix: alb. ep. calc. act greenschist CGR8B 209 355757 6376911 amyg Pyx Plag PhyriC andn amygs: ep. alb. shl. 41r: greenschist CGR8S 333 351968 6378389 XU lith andt(7) tuff-brx vnls. matrix: ep. act. chl. greenschist CGR8S 346 355623 6375885 hornlelsed(7) lith xtl andtt(?) matrix: hb. plag=AnM-35 hbhomfels DER8S 357 337577 6395744 lith XU vitric laplash tuff matrix: chl. calc transitional DER88 366-3 339521 6396285 x11 lilh my(?) tuff vnns: qtz calc. Chl(?) transitional DER91- 8 344513 6412395 YOlC SSWS15 matrix: Chl. calc; vnlets: calc transitional DER91- 12 345331 6413366 plag pyx XU lith lap tuff xus: calc. chl. opaques; transitional DER91- 15 347855 6417740 plag x11 lith tuff amygs: Chl. pr. cab. qh: P+PP DER91- 21 340514 6417145 plag hb pyx XU lith luff malrix: chl. calc. pr Pw DER91- 27-2 349852 6417224 pyx plag hb phyricbas xtls: Chl. calc. ser: vnlets: transitional DBR91- 31 350816 6417425 pyx hb plag x11 lith lap tuff matrix: calc. Chl. alb: vnlets: transitional DER91- 32 351501 6417435 plag hb pyx phyriCbas matrix Chl. alb. ser. cab; w-pp DER91- 69 348738 E413859 pyx phyric bas brx amygs: Le. chl. qkcalc zeolite DER91- 82 346165 64227n bladed Plag pyx phyric matrix: chl. calc. ep: vnlt: greenschist DER91- 82-2 345160 6421n5 plag hb pyxXU lith tuff Xtls: chl. calc. Opaques: greenschist DER91- 101 342497 6417685 plag pyx XU tuff matrix: chl. calc transitional DER91- 124 343747 6423648 bladed plag pyx phyric mati*: chi ep transitional DER91- 220 331959 6413569 plag pyx X11 18th lap tuff matrix: Chl. PP: wet: pr. pr-PP DER91- 534 338139 6429916 pyx XU 11th tuff matrix: act. Chl. alb greenschisl DER91- 535 338286 6430030 pyx xtl lilh tuff matrix: act. Chl. alb greenschist

- Bulletin 95 157 MinislryyqfEmploymenf and Inveslmnl

SAMPLE NO UTM Zn 09 LITHOLOGY METAMORPHICMETAMORPHIC EAST NORTH GRADE ASSEMBLAGE

DBRQ1- 540 3M587 6413755 plag-rich tuff wacke matrix: calc. PP. pr. chl. ep pr-w DBR91- 552 336246 €414459 plag pyx xtl lilh lap 1°K matrix: chl transitional DBR91-334893 556 6415872 ams hb phyricbas amygs: cab. Chl. ep; vnlels: transitional DBR91- 581 351503 6418008 aphyric bas matrix: chl. cab: vnlels: transilianal DBR91- 584 351213 6418628 plag hb dl lith lap tuff matrix: chl. calc transitional DBRQ1- 587 350600 6419317 pyx Xu lith lap tufl matrix: chl. calc transitional DBR91-351482 593 6420614 hb plag pyx phyricbas matrix: chl. calc. ep transitional DBRQ1-351704 601 6421915 plag hb XU liul lap tuff malrix: chl. calc. opaques: greenschist DBR91-322954 604 6411474 VOlC SIS ""let:calC transitional DMU91-346104 13 6414436 amyg pyx plag phyricandn amygS: Chl. =IC, eP transitional INE91- 7 349079 6416171 plag pyx lith XU 1°K amyg: chl. qtz. calc. ep. Pr; PwP INE91- 34344604 6418482 plag pyx Xu liul lap tuff matrix: Chl. cab. qk transitional JT191- 77 343921 6426027 bsltic asNxti tuff - tuffaceous matrix: act, chl. alb greenschisl JT191- 112 330838 6419807 amyg plag phyric andvbas amyg: chl. cab. pr; matrix: Pr-w JT191. 114 349612 6420129 hb plag phyric diabase? matrix: Chl. cab. qtr. ep. pp: transitional JT191- 117 348901 6418473 amyg plag phyricbas amyg: Chl. =IC. Ze? transitional JT191- 118 348941 6418072 tuffac ssWgrit amygs: Chl. cak, vnles: chl. transnional JT191- 121 348669 6417630 massive andt silvflow matrix: ad. chl. ep. calc. chl transilional JT191-324983 126 €415167 amy9 hb plag PYX phyric bas matrix: calc; amygs: qtz. transitional JT191-324594 128 6414551 amy9 hb plag PYX phyric bas amygs: qlz. Chl. calc. PP pr-w JT191- 136 323697 6413466 plag hb phyricand1 matrix: Chl. calc transitional

HAZELTON GROUP: CG R89- 51CGR89- 354443 6390737 amyg 01 pyx plag phyricbas amyg: chl. calc. ep: vnlt: greenschist CGR84 162 353593 6388824 a((?) pyx plag Phyric bas vnlts: calc. chl. ep. alb. greenschist CGR8P 227 356604 6381458 OK?) pyx(?) plag phyric vnltr and1 matrix: qtr. Chl. transitional CGR89-467 355236 6380092 (ol?) pyx plag phyric bsltic Ca-plag (An55): VnllS: =IC: Mnsitional DER84 184 347397 6386705 amyg 01 plag PYX phyric bas amygs and1 vnlts: chl. alb. transitional DBR89- 430 354407 6381909 OK?) pyx pia9 phyricbas Ca-plag: al1n:chl. calc afler transitional CGR89- 160 353953 6388984 meta-and1 matrix: calcic plag, hb uppergreenschist CGR80 434 350072 6385284 pyx-plag Phyricand1 amyg: chl. calc. qk transitional CGR89-214 355339 6377986 xu lith andesiti ash tuff matrix: chl. calc transitional CGR89-217 355389 6378238 XU (plag) lith and1 lap tuff-bn amygr and1 matrix: chl. greenschist CGR89-229 356793 6381361 sparsely amyg PYX Plag and1 amygs and1vnlts: qtz, chl. transitional CGR84 237 356002 6380736 hb pyx plag phyric bsltic and1 plag=An50 transitional CGR89-363 352219 6382972 hornfelsed(?) andesiticlfelsic hornfels: biotite. act. alb; biaotite hornfels(?) CGR8S 437-2 351019 6384718 amYg (PYX) Plag amyg and1 matrix: act. ab. QTeWGChiSt CGR89- 439 346412 6387905 pyx plag phyric bslticandl Ca-plag (An47): altn: chl. transltional CGR89- 48 363364 6390305 (hb?) pyx plag Phyricand1 ah: calc. chl: plag=An48 transitional CGR8P 511 354835 6386287 amyg hb plag phyric andt amygs: chl. act. qlz Ca- transitional DBR8S 147 363974 6388675 amyg (017) plag phyric bsltic amyg: chl. calc.qtr indeterminate DER89 136-2 366740 6388629 trachytic amygand1 now bn amygs: calc. chl, ep.qk transilional DBR89- 136-2 366739 6388629 lrachgic amyg and1 now bn amyg: calc. qtz. transitional DBR89- 155 349364 6389572 bladed plag phyric andt amyg: cab. qk. chl. alb(?) transitional DBR8S 326 354588 6381203 hb plag phyric and1 vnlts: calc. 412. alb: ann: transitional OBRES 432 353476 6381935 trachytic pyx plag phyric Ca-plag: amygs: chl. calc. transitional DBR89- 69-1 354864 6387519 hb plag phyriC bsltic(?) and1 matrix and1 phenwlysls: greenschisl MGU89- 92 348900 6387140 amyg andt (vitric) x71 lilh lap amygs: chl. calc.qtz. alb lransitional MGU89 991 349497 6386531 amy9 pyx plag phyric bsltic amygs: chl. calc. ep.alb greenschist DER89 435 353139 6382257 amyg plas Phyric dac amygs: calc. alb. qtr. chl transilional

SUSTUT GROUP: CGR8S 200-3 353526 6395831 amyg pyx plag phyric bsltic amygs: Chl. calc. qtz. transitional CGR89 128-2 360116 6393971 pyx plag phylic bsltic and1 amyg: calc. chl; Ca-plag transitional CGR89- 2W-2 353526 6395831 sparsely am* Pia9 phylic amygs: chl. calc. W; transitional CGR8S 179 351300 6390380 trachytic rhyodac plag chl. calc.e~? transilional

~ ~ "" 158 Minisrrv of Employment and Investment

SAMPLE NO UTM Zn 09 LITHOLOGY METAMORPHIC METAMORPHIC EAST NORTH ASSEMBLAGE GRADE

DBR89- 376 354146 6391935 rhyoliic Xu VilriC ash luff matrix: ze(?) zeolite DBR89- 415-2 37m 6384950 welded lilh Xu vilric rhyash matrix: ze zeolile

SLOKO GROUP: DER89 468 341288 6394369 pyx plag phyric bsllic andl Caplag transitional DBR89- 469 341110 6394305 pyx plag phyric bsliic andl Ca-plag: amygs: cab. chl transitional JBR8S 470 340904 6394217 pyx plag phyric baJmsnic Ca-plag; amygs (rare):calc. lransitional ,JBR8% 458 341138 6394284 (hb) pyx plag phyric bsllic amygs: chl, WlC; plag=An47 transitional :3BR89- 460 341275 6394381 (hblpyx?) plag phyricandl amygs: Chl. cab. qtr; Ca- transitional IJBR8P 467 341289 6394367 pyx plag phyricandl Ca-plag: ann: chl. qfz. calc VanSitional l3BR8P 471 340902 6394216 hb plag phyricand1 flow bn: amygs: chl. ze zeolite 13BR89- 6 353026 6391935 amm femspar phyTlc andl(?) amygs: chl. qfz lransitional 13BR89- 198-3 353015 6392471 amyg hb feldsparphyric amygs: Chl. 412. calc. ze(?) zeolite

INTRUSIONS WITH METAMORPHIC MINERAL ASSEMBLAGES: ICGR89- 34 367461 6389197 phyncplag amyg andl amygs:calc. chl. ep ICGR89- 377 335494 6393085 pyx grained coarse vnb: pr pwp lDBR89- 64-2 355225 6389852 amyg phyric bas die amygs: tak. (qtz) transitional IDBR89- 374 356795 6399091 vnlls: calc. pr. chl pwp

Abbreviations: dac- dacile: ana- andesite: bas - basan; bsllic - basaltic; XU - crystal; lith - lilhic: lap - lapilli; amm - arnygdalokdal: hb - hornblende; lpyx - pyroxene; plag - plagioclase; 01 -olivine; bio-bwlile; chl - chbrile; calc - calcite; qlz. qua@: alb - albiote; ze- zwlile: pr - prehnile: pp - pumpellyile: ep - epidole; act - actinolite: lrem - tremolite: py - pyrite: brx - breccia; rhy- rholile: cpx- clinopyroxene; opx-

Bulletin 95 I59 160 Geological Survey Branch n”...T”., nrrmyum. L. .t WHOLE-ROCK LITHOGEOCHEMICAL ANALYSES OF PLUTONIC ROCKS 3 FIELD NO NTSMAPUTM UTM MAP ROCK UP SIO. no,Fe,Ox AI,O, MnO MgO CEO Na20P,O. K,O Zone8FIELDCODE CODE NORTH EAST % x % % % % % % % % DBtection Llmib: 0.01 0.010.01 0.01 0.01 0.010.01 0.01 0.01 0.01 A~lyti~lTechnlques: XRFllCPXRFllCP XRFllCP XRFllCPXRFllCP XRFllCPXRFllCP XRFllCP XRFflCP XRFllCP

GRNT MNGRNT 74.88 0.17 13.78 1.46 0.06 0.21 1.39 3.44 4.47 0.03 GRNT GRDR 70.26 0.36 15.20 2.60 0.08 0.67 2.05 4.12 3.54 0.13 MNZN MNGRNT 75.75 0.14 13.32 1.20 0.05 0.16 1.08 3.28 4.63 0.02 MGU89-209-3 GRNT MNGRNT 76.54 0.15 12.83 1 a2 0.03 0.06 0.58 3.49 4.71 0.02 MGU89-213-2 GRNT MNGRNT 76.48 0.12 13.07 0.80 0.01 0.06 0.37 2.89 5.13 0.01 MGU89-221 GRNT MNGRNT 68.28 0.58 15.17 3.55 0.07 1.M 2.35 3.68 4.59 0.18 MGU89-224 104G12 329990 6388052 GRNT MNGRNT 73.73 0.26 13.77 1.53 0.04 0.38 1.14 3.54 4.83 0.06 MGU89-224DUP 104G12 329990 6388052 GRNT MNGRNT 73.81 0.26 13.77 1.53 0.03 0.36 1.14 3.54 4.85 0.06 MGU89-232 104G12 330680 6388349 GRNT MNGRNT 71.35 0.38 14.19 2.29 0.04 0.62 1.11 3.39 5.03 0.11 ChdsUM pluton: MGU88-W 1WG05 332316 6349874 GRDR TNLT 59.28 0.69 18.23 6.56 0.13 2.44 6.51 3.35 1.74 0.25 DIKES DBR88290-2‘ 104005 347682 6371082 RYLT MNGRNT 63.24 0.59 17.84 4.68 0.12 1.29 4.02 4.87 2.57 0.20 DBR89-380 1WG11 349463 6387294 ANDs GRDR 61.47 0.71 15.02 5.07 0.09 2.28 3.71 3.66 3.17 0.21 DBR84380DUP 1WG11 349463 6387294 ANDs GRDR 61.69 0.71 14.99 5.10 0.09 2.30 3.70 3.59 3.03 0.20 MIDDLE JURASSIC.Three Sisters suite Niko pluton: DBR88328’ 352733104G06 6360764 GRNT MNGRNT 74.11 0.21 13.65 1.96 0.06 0.28 1.37 3.77 3.64 0.04 saffron pluton: CGR89.495’ 1MG11 359129 6384068 GRNT MNGRNT 68.76 0.38 15.26 3.04 0.04 0.69 1 .64 4.03 4.58 0.09 CGR84517’ lMGI1 354301 6385459 MONZ QZMZDR 53.73 0.95 16.88 8.05 0.1 1 3.93 7.43 3.66 2.39 0.32 CGR89-513 1MG11 355410 6386169 SYNT MNGRNT 71.88 0.30 14.14 2.52 0.03 0.35 0.26 3.30 5.47 0.39 Yehlnlko plulon: MGU88-I01 1WGW 360497 6367640 GRNT MNGRNT 76.60 0.15 12.78 1.39 0.04 0.14 0.88 3.21 4.43 0.02 MGU88-193 104G06 360944 6385404 GRNT MNGRNT 75.61 0.20 13.31 1.69 0.M 0.25 1.14 3.19 4.30 0.03 Canover pluton: CGR89-546’ lWG12 3381406393551 MNZN GRDR 58.47 0.67 16.72 7.44 0.18 2.74 6.42 3.M 2.34 0.21 DIKES CGR89-34 6389197367461 104G11 FPPP QZMZDR 51.18 1.31 16.98 9.58 0.22 2.85 4.36 4.94 2.88 0.29 LATE EARLYJURASSIC -Cone Mounlaln rub DBR9040’ 104G05 340300 6360530 GRDR MNGRNT 68.42 0.31 15.39 2.96 0.08 0.71 2.52 3.34 4.66 0.08 Navo pluton : DBR88329’1040% 348562 6359899 GROR GRDR 67.31 0.45 15.98 3.76 0.07 1.34 3.77 4.00 2.23 0.13 Dokdaon pluton: DBR8B331’ lMG06 6371030349807 GRDR GRDR 65.51 0.49 15.54 5.22 0.09 1.97 4.89 3.08 2.58 0.13 Strata Glacler pluton M G U8&1 94 104G06 356351 6386738356351 104G06MGU8&194 GRDR TNLT 64.69 0.57 16.52 4.83 0.09 1.95 4.75 3.90 1.82 0.15 EARLY JURASSIC -Texas Creek suite Llmpoka pluton: D ER 91-723’ 104G13 331083104G13DER91-723’ 6408326 QZMZDR QZMZDR 61.03 0.62 16.88 6.25 0.15 1.% 5.39 3.42 3.10 0.24 Geology Ridge pluton DBR9O.1 104005 329237 8380819 DORT DORT 52.72 0.66 11.41 8.88 0.22 10.30 11.60 1.74 0.33 0.21 DER9O.lDUP 104G05 329237 6360819 DORT DORT 52.77 0.66 1 1.52 8.88 0.22 10.34 11.56 1.75 0.34 0.21 ! FIELD NO NTSMAP UTM UTM MAP ROCK QAP LO1 OX-SUM Fe2Ox FeO s Cot NI MO Zn Cr Ba Sr Rb Zona9 EAST NORTH CODE CODE FIELD x % x x x x ppmppmppm ppm ppm ppm ppm Detectlon Umlhi: 0.01 5 8 2 10 io 5 io AnaWcal Technlques: XRFllCP XRFllCP CdC. TIT PIPS PIPS PIPS XRF XRFXRF EOCENE. Hyder suite - Sawback pluton: DBR88-108 1WG05 319895 6367806 GRNT MNGRNT0.29 99.88 0.52 0.85 0.01 0.15 2 8 29 722 134 167 DBR88-163 329826104G05 6365610 GRNT 0.52 GRDR 99.53 1.18 1.28 0.01 0.15 3 8 35 2088 527 51_. MGU8876' 327946104G05 6374268 MNZN MNGRNT0.21 99.84 0.57 0.57 0.01 0.15 2 8 22 539 112 148 M GU 69-ZW -3 104G12 333095104G12 MGU69-ZW-3 6385634 GRNT MNGRNT 0.42 99.65 0.62 0.36 0.01 0.14 11 2 308 62 261 MGU89-213-2 332545104G12 6386823 GRNT MNGRNT1.05 99.99 0.56 0.22 0.01 0.14 14 2 156 40 238 MGU89-221 329227104G12 6387981 GRNT MNGRNT 0.39 99.88 1.e4 1.72 0.01 0.14 52 14 1964 537 102 MGU89-224 329990104G12 6388052 GRNT MNGRNT0.34 99.62 0.65 0.79 0.01 0.14 27 6 930 233 116 MGU89-224DUP lWGl2 329990 6388052 GRNT MNGRNT0.34 99.69 0.50 0.93 0.01 0.14 27 5 905 232 117 MGU89-232 330680104G12 6388349 GRNT MNGRNT 0.81 99.32 1.01 1.15 0.01 0.14 33 9 1742 447 90 ChdsUna pluton: MGUBB48' 1MG05 332316 6349074 GRDR TNLT 0.60 99.78 2.89 3.30 0.01 0.15 28 25 1599 921 23 DIKES

DBR88-29'&2' 104005 347682 6371082 RYLT MNGRNT 0.41 99~83 2.32 2.12~~ 0.02 0.15 36 13 2017 797 DBR89-380 1WG11 349463 6387294 ANDs 3.96 GRDR 99.35 2.01 0.01 1.88 53 35 1443 597 76 DBR89380DUP 1WG11 349463 6387294 ANDs 3.96 GRDR 99.36 2.01 0.01 1.88 51 34 1452 595 75 MIDDLE JURASSIC -Three Slstera sulhi Nlko pluton: DBRW-328' 352733 104G06 63607€4 mJgn GRNT MNGRNT0.42 99.51 0.70 1.13 0.01 0.15 281705 22 74 163 Saffron pluton: CGR89-495. 104G113591296384068 mJgn GRNT MNGRNT 0.85 99.56 1.28 1.58 0.01 0.14 20 7102 2261254 CGR69-51r 1WG11 3543016385459 mJgn MONZ OZMZDR 1.92 99.37 2.45 5.M 0.01 0.65 29 41 807 62491 CGR89-513 104G113554106386169 Dikes SYNT MNGRNT1.32 99.66 1.60 0.65 0.01 0.14 31 5 1736 101 113 Yehlnlko pluton: MGU8&101 lMG066367640 360497 mJgn GRNT MNGRNT0.33 99.97 0.45 0.85 0.01 0.15 26 46 2386 €47 30 M G U881 93 1MG06MGU88193 360944 6365404 mJgn GRNT MNGRNT 0.27 100.03 -1.15 2.56 0.01 0.15 28 10 1019114 117 Conover pluton: CGR89-546' 1MG12 3381406393551 mJm MNZN 1.04 GRDR 99.27 3.44 3.60 0.01 0.14 7335 594 4299 29 DIKES C GR 89-34 104G11 367461 6389197367461 104G11 CGR89-34 Dikes FPPP QZMZDR4.48 99.07 4.00 5.02 0.03 1.w 5461436 21 115 48 LATE EARLYJURASSIC. Cone Mountain sulte DBRW4O' 1WG05 34OOW 6360530 leJgd GRDR MNGRNT 0.55 99.02 2.90 1.55 0.05 0.14 10 3442102 10 Navo pluton : D BR8 8-329' 104G06 348562 6359899348562 104G06DBR88-329' lead GRDR GRDR 0.43 99.47 1.78 1.78 0.01 0.15 48 51419 1141 19 Dokdaon pluton: DBR88-331' 1MG06 6371030349807 le&d GRDR GROR 0.54 100.04 2.21 2.71 0.01 0.15 38 57462 1546 38 Strata Glacler pluton M GU 8&19 4 104G06 356351 6366738356351 104G06MGU8&194 leJgd GRDR TNLT 0.46 99.75 1.x@ 2.56 0.01 0.15 78 18 23509 1073 EARLY JURASSIC. Texas Creek sulle Umpoke pluton: DBR91-723. 104G133310836408326 eJmd QZMZDR QZMZOR 0.69 99.73 6.25 2.71 912 14 63 Geology Ridge pluton DBRSO-1 104G053292376360819 eJd DORT 1.14 OORT 99.21 8.87 5.29 0.01 0.14 650 252 10298 DBRSO-1DUP 1WGO53292376360819 eJd DORT 1.14 DORT 99.39 8.87 6.12 0.01 0.14 €49 252 296 10 FIELD NO NTSMAP UTMUTM MAP ROCK QAP Zr Y Nb Ts v La YbPd Pt Sn m U Zone9 EASTNORTHCODE CODE FIELDppm ppmppm ppm Ppm ppm Ppm ppn Ppm Ppm PpmPpm D etection Urnlta: Detection 20 10 5 NA 5 15 NA NA NA Analylical Tachnlques: XRF XRF XRF XRF XRF XRF XRF XRF XRF XRF XRF XRF EOCENE - Hyder suite

DBR88-108 1WGO53198956367806 GRNT MNGRNT 121 24 24 5 24 19 7 DBR88-163 104G053298266365610 GRNT GRDR 149 13 17 5 53 22 5 MGUB8-76' 104005 3279468374266 MNZN MNGRNT 1W 20 21 522 15 8 MGU89-209-3 104012 3330956365834 GRNT MNGRNT 102 12 21 7 25 MGU89-213-2 104G123325456386823 GRNT MNGRNT 76 11 22 4 3 MGU89-221 1WG126387961 329227 GRNT MNGRNT 279 25 18 56 60 MGU89-224 1WG12 3299906388052 GRNT MNGRNT 158 16 13 15 42 MGU89-224DUP lMG12 3299906388052 GRNT MNGRNT 155 17 13 15 38 MGU89-232 104012 330680 6388349 GRNT MNGRNT I69 29 12 37 36 Christina pluton: MGUB8-48' 104G05 332316 6349874 GRDR TNLT 179 18 12 5 137 35 5 DIKES DBR8azwy 104G05 347682 6371082 RYLT MNGRNT DBR89-380 104G11 349463 8387294 ANDs GRDR 134 17 6 108 24 DBR89-38WUP 104G11 349463 6387294 ANDs GRDR 144 17 7 103 17 MIDDLE JURASSIC. Thme Slstar. mI(B Niko pluton: DBR~~-328. 104006 352733 6360764 GRNT MNGRNT 15% 24 18 5 31 33 8 ssnron pluton: CGR89495' 359129104G11 8364068 GRNT MNGRNT 276 26 11 34 24 CGR89-517' l04Gll 354301 6365459 MONZ QZMZDR 116 30 6 226 25 CGR89-513 104Gll 355410 6386169 SYNT MNGRNT 170 24 10 22 13 Yehinlka pluton: MGUB8-101 104G06 360497 6367640 GRNT MNGRNT 118 16 10 5 118 22 7 MGUB&193 104Gffi 360914 6365404 GRNT MNGRNT 1Z6 16 15 53Li 17 6 Conover pluton: CGR89-546' 6393551336140 104G12 MNZN GRDR 111 22 3 174 22 DIKES CGR89-34 104Gll8389197 367461 FPPP QZMZDR 145 32 9 287 22 LATE EARLY JURASSIC. Cone Mountain sulte DBR9MO' 104G05 34wOO 6360530 GRDR MNGRNT 197 22 19 43 43 Navo pluton : DBR88-329' lWG06 348562 6359899 GRDR GRDR 128 15 14 5 72 15 5 Dokdaon pluton: DB R88-331' 104G06 349807 6371030349807 104G06DBR88-331' GRDR GRDR 125 18 11 5 128 23 9 Strata Glacler pluton MGU88-194 lWG066356736 356351 GRDR TN LT 149 18 11 599 22 6 EARLY JURASSIC -Texas Creek sulta Llmpoke pluton: DBR91-723' 6408326331083 104G13 QZMZDR QZMZDR 151 26 7 45 Geology Ride8 pluton DBR90-1 104005 329237 6360819 DORT DORT 91 25 5 202 15 D8R90-1DUP 104G05 329237 6360819 DORT DORT 94 26 12 207 21 ...... - ...... kLYJURASSIC. Copper Mountain suite Rugged Mowttaln pluton - syenltes INE91-121 104G13 343900 6410055 eJs SYNT FSYNT 51.86 0.64 19.29 5.65 0.15 1.41 6.33 2.45 8.68 0.29 INE91-122 104G13 343815 6409693 e& SYNT FSYNT 52.51 0.76 19.26 5.56 0.17 1.51 5.51 3.24 8.27 0.28 INE91-316 104G13 345938 6408895 eJs SYNT FSYNT 53.72 0.52 20.78 4.51 0.13 0.99 4.91 2.96 9.03 0.24 INE91-317 104G13 3461 11 6408964 eJs SYNT FSYNT 50.42 0.63 18.93 5.75 0.15 1.41 6.71 2.23 8.49 0.34 INE91-320 104G13 346485 6409053 eJs SYNT FSYNT 51.17 0.85 18.71 7.30 0.18 1.76 7.74 1.75 8.51 0.46 INE91-322 104013 346472 6408613 *JS SYNT FSYNT 54.12 0.68 20.35 4.79 0.13 0.70 4.59 2.25 10.70 0.16 INE91-324 104G13 346493 6408088 eJs SYNT FSYNT 51.52 0.99 20.09 6.00 0.12 1.32 4.98 2.34 10.24 0.32 INE91-82 104G13 345489 6410465 Dikes SYNT FSYNT 58.74 0.28 19.88 2.23 0.08 0.40 2.62 1.87 11.78 0.01 INE9164 104G13 347313 6409513 Dikes SYNT FSYNT 60.28 0.14 21 .OB 1.74 0.03 0.14 2.86 5.29 7.49 0.01 INE91-73-2 104G13 348298 6410221 Dikes SYNT FSYNT 57.09 0.54 19.21 4.62 0.10 1.06 4.86 3.79 8.00 0.22 INE91-76 l04G13 346069 6409865 eJslTJcpx SYNTIPRXN NA 46.43 0.97 15.24 9.71 0.20 3.43 10.79 1.16 7.73 0.83 INE91-115 104G13 345096 6410460 eJflJcpX SYNTIPRXN NA 47.73 0.99 15.23 9.89 0.17 3.33 10.33 0.79 7.03 0.82 INE91-336 1WG13 343829 6410644 eJflJcpx SYNTlPRXN NA 48.56 0.92 15.52 9.32 0.18 3.88 9.91 1.38 7.54 0.91 Rugged Mountaln ultramafic phase INE91-78-2 104G13345738 6409800 TJcpx PRXN NA 38.90 1.54 3.20 21.02 0.34 9.96 21.33 0.81 0.06 2.56 INE91-80-2 1WG13 345626 6410045 TJcpx PRXN NA 37.59 1A7 4.47 18.55 0.32 7.91 20.24 0.87 1.23 2.31 INE91-80-2DU 104G13345626 6410045 TJPX PRXN NA 37.16 1.44 4.42 18.30 0.32 7.78 20.04 0.85 1.30 2.28 ultramante bodies Lamer lake pluton DBR91-382-2 338633104G13 6417196 TJcpx CPXN NA 39.21 1.50 5.34 19.51 0.20 10.95 20.46 0.23 0.18 1.34 DBR91-387 104013 338096 6416989 TJcpx CPXN NA 39.55 1.59 5.74 21 .01 0.20 11.00 18.59 0.23 0.28 0.04 DamnaUon pluton INE91-282 104G13 348525 6416034 TJcpx CPXN NA 40.20 1.50 4.04 22.25 0.20 11.44 18.21 0.26 0.31 0.18 Quartz monzonlte varlatlon Perslshln pluton: MGU88-102' 104G05 341169 6352116 eJqm MNZN QZMZDR 60.16 0.59 17.85 6.10 0.17 1.77 6.69 3.34 2.30 0.24 MGU88-190 1WG05 335928 6355747 eJqm MNZN GRDR 64.80 0.50 16.15 4.82 0.13 1.42 434 3.05 3.31 0.16 MIDDLE(?) TO LATE TFUASSIC - Polaris sulk? Mount Hlckman Complex MGU88-184 1WG06 374058 6347932 lTcx CPXN NA 49.58 0.35 1.16 9.22 0.19 17.31 19.52 0.19 0.01 0.01 D BR8B -314 104G06 375952 104G06DBR8B-314 6350727 ITcx PRXN NA 43.99 0.18 1.16 12.00 0.21 24.52 11.95 0.01 0.00 0.01 Middle Scud Creek body MMC86-224 lWG06 360224 6350671 lTcx CPXN NA 43.70 0.47 7.66 10.26 0.18 20.89 9.58 0.78 0.27 0.11 DBR8B-243 104Gffi 361339 6349375 lTcx GBBR NA 43.22 0.36 5.31 11.03 0.18 29.10 6.69 0.30 0.05 0.07 Yehlnko Lake body MGU89-111 1WG11 360372 6360596 lTcx CPXN NA 42.41 0.32 4.92 10.89 0.18 27.78 7.05 0.47 0.08 0.08 MGU89-114 104011 360008 6360195 rrcx CPXN NA 40.27 0.32 4.71 10.87 0.18 30.86 4.71 0.30 0.03 0.07 MGU89-121 104Gll 359714 6377724 rrcx CPXN NA 41.26 0.29 4.16 10.80 0.16 29.96 5.31 0.15 0.04 0.07 MGU89-158 104Gll 359664 6376552 lTcx CPXN NA 40.43 0.34 4.39 10.77 0.19 29.86 6.02 0.32 0.10 0.w MIDDLE TO LATETRIASSIC - Stiklne sulta Hickman bathollth DBR8B322 104Gffi 385956 6350407 ITm MNZN GRDR 63.56 0.51 16.57 4.95 0.10 2.01 4.43 4.14 2.52 0.18 MGU88-192 1WG06 369187 6356802 ITm GRDR GRDR 65.28 0.47 16.28 4.16 0.09 1.74 4.04 4.10 2.56 0.14 DBR8B-325 104Gffi 363815 6352467 ITm MNZN QZMZDR 53.73 1.w 17.61 8.88 0.18 3.59 8.00 3.42 2.07 0.34 M GU 88-197 104G06MGU88-197 362995 6351733 ITm MNZN QZMZDR 57.76 0.82 19.10 5.81 0.12 1.49 5.42 4.05 4.37 0.53 Nlghtout pluton MGU88-204 1WG06 375004 6373914 WJ GRDR GRDR 86.13 0.Y) 16.85 3.30 0.07 1.28 3.94 4.76 2.19 0.11 MGU89-52 1WG11 361593 6402281 W GRDR TNLT 59.44 0.60 17.71 6.19 0.14 2.46 6.21 4.19 0.86 0.21 CGR8S525 1MG11 363661 6375334 mad GRDR GRDR 64.34 0.51 16.12 4.44 0.09 1.89 4.18 4.18 2.73 0.15 ... . Analytical Techniques: calc.XRFllCP XRFllCP TIT XRF AASXRF AAS AAS XRF LATE TRIASSIC TO EARLY JURASSIC. Copper Mountain sulle Rugged MOUmln pluton -ryenltes INE91-121 104G13 343900 641W55 eJs SYNT FSYNT 2.32 99.07 2.74 2.81 52 INT 175 INE91-122 104G13 343815 6409693 eJS SYNT FSYNT 3.67 100.74 3.19 2.19 135 INE91-316 1WG13 345936 6408895SYNT eJs FSYNT 2.58 100.37 2.33 2.03 <50 4 145 INE91-317 104G13 346111 6408964SYNT eJ5 FSYNT 4.06 99.12 2.97 2.77 169 INE91-320 1MG13 346465 6409053 eJs SYNT FSYNT 2.01 100.46 3.46 3.60 200 iNE91-322 104G13 346472 6408613 eJs SYNT FSYNT 2.39 100.88 2.51 3.25 40 1105 204 INE91-324 104G13 346493 6408088 eJs SYNT FSYNT 2.93 100.85 1.57 3.21 16 1498 274 INE91-82 104G13 345489 6410465 Dikes SYNT FSYNT 1.76 99.65 1.oa 1.07

MGU88-204 1WGffi 375004 6373914 lTgd GRDR GRDR 144 12 5 72~~ 15 MGU89-52 1WG11 361593 6402261 lTgd GRDR TNLT 115 20 125 21 CGR89-525 363661104G11 6375334 lTgd GRDR GRDR 146 23 5 87 8 FIELD NO MAPNTS UTM UTM ROCK MAP QAP SIO, no, AlrOl Fe.O!, MnO zom s EAST NORTH CODE CODE FIELD % % x x x .. .. OBlscUon Llmlls 0.01 0.01 0.01 0.01 0.Of 0.010.01 0.01 0.01 0.01 Analytical Techniques: XRFllCP XRFIICP XRFllCP XRFllCP XRFllCP XRFllCP XRFIICP XRFllCP XRFIICP XRFllCP Tahltan Lake pluton DBR91-724 104G13 342364 6425433 TJSd QZMNZN QZMZDR 59.45 0.51 17.68 5.81 0.14 1.973.69 6.46 1.78 0.25 INE91-244 1WG13 344238 6425218 TJgd QZDORT QZMZDR 53.94 0.68 18.16 8.39 0.20 2.82 8.671.16 3.19 0.25 JT191-72 104G13 345075 6425634 TJgd QZDORT DORT 49.59 0.75 19.42 9.061.49 3.120.21 10.09 3.38 0.28 Llme Tahltan Lake pluton lNE91-225 1WG13 lNE91-225 3260426425667 GRDRTJhqd GRDR 60.65 0.50 18.16 5.24 0.165.10 1.37 1.91 3.87 0.20 Tahlbn River pluton WMC91-52 1WG13 342555 6430607 TJhqm QZMZDR GRDR bl.33 0.47 16.97 4.21 4.430.10 4.92 1.32 I.72 0.14 WMC91-52DUP 1WG13 342555 6430607 TJhqm QZMZDR 64.29GRDR 0.47 17.04 4.20 0.1 14.92 1.31 4.41 1.61 0.13

FiELDNO NTSMAP UTM UTM MAP ROCK (UP LO1 OX-SUM Fe,,O, FeO S Co. Ni Mo Zn Cr Ba Sr Rb Zone8 EAST CODENORTH CODE FIELD x x x 70% % ppm ppm ppm ppm ppm ppm ppm Detection Umlls: 0.01 510 8 2 10 5 10 AnalyUcal Techniques: XRFIICP XRFIICP dc. nr MS AAS AASXRF XRF XRF MGU68.197 1MG06MNZN iTm6351733 362995 QZMZDR2.01 99.98 0.51 0.15 0.01 3.42 28 23 908125 562

Nlohtaul~ .. "Innon MGU88.204 1MG06 GRDR375WGRDR lTgd 6373914 1.7499.62 0.61 1.40 0.01 0.15 66 35 1036 835 35 M G U89-52 1WG11 361593 6402281 IT@6402281 361593 1WG11MGU89-52 99.54 1.51 TNLTGRDR 2.64 3.010.14 0.01 66 21 852 16 827 CGR69-525 lWG11 363661GRDR lTgd 6375334 0.72 GRDR 1.81 99.35 2.370.14 0.01 59 26 1451 660 68 Tahltan Lake pluton DBR91-724 1MG13 342W 6425433QZMNZN TJ QZMZDR 1.56 99.50 5.81 2.51

FIELDNTSMAP NO UTM UTM ROCKMAP QAAP Zr Y Nb Ta V La Yb Pl Pd Sn Th u Zone9 EAST NORTHCODECODE FIELD ppm ppm ppm ppn ppm pp" ppm ppm ppm ppm ppmppm Detection Umlb: 20 10 5 NA 5 15 NA NA NA Analytical Techniques: XRF XRF XRF XRF XRFXRF XRF XRF XRF XRFXRF XRF MGUB8-197 lWG06 362995MNZN 6351733ITm QZMZDR32 272 20 519 127 6 Nlghtoul pluton MGUB8-204 1WG06 375W 6373914 12lTgd 144GRDR GRDR 7 5 72 15 6 MGU89-52 lWG11 361593 6402281 lTgd TNLTGRDR 115 20 1 21 125 CGRB9-525 1MG11 lTgd6375324363661 146GRDR GRDR 23 5 87 8 TaMbn Lake pluton DBR91-724 1MG13 342364 6425433QZMNZN TJ QZMZDR 80 16 <5 <15 45 45 c15 INE91-244 104G13 344238 6425218 TJ QZDORT QZMZDR19 67 c5 -35 <15

168 Geological Survey Branch - Minislry of Employmolt ond Investment

APPENDIX 12 POTASSIUM-ARGON ANALYTICAL DATA AND DATESFOR STRATIFIED AND PLUTONIC ROCKS

FEW W NTS UTM IZNW) ROCK PLUTON DATING MINERAL K 4VAr 4OAr AGE -NO. CODE W EAST NORMGROUP TYPE MEWOD I%) IxlMscigm) (*I (ma)

MGU8876 1WG05 327946 Kdr Bi 8.65 t 0.07 12.574 59.7 48.0f1.7 DEW9471 lMG11 352738 KJV Hb 0.577fO.Wl 1.110 79.6 488* 1.7 DBRW-290-2 1MGO5 347688 U.Ar Bi 6.090 i 0 030 11.922 90.9 49.7* 1.7 DElR89-376 VXGII 354146 Kdr WR 4.170i0.010 8.490 85.2 51.6* 1.8 MGU8848 104G05 332316 Kdr 5.76 BI t 0.04 12.368 53.5 54.2 * 1.9 MGUW8 104W5 332316 K-Ar Hb 0.695 t 0.W1 1.539 83.4 58.1 t2.0 DELR89-25 104Gll 358247 Kdr Bi 5.82 2 0.02 19.815 62.2 856&3.0 CGR89-217 104G12 355389 Kdr WR 0.475 i 0.002 2.843 86.9 1485 5 MGU69-314 104005 341176 K-Ar HQ 0.M7 i 0.m 4.073 329 155+5 DE.RW-331 104G05 348807 U-Ar Hb 0.712 i 0.W 4.58 88.8 158*8 C(iR89495 1MG12 359129 Kdr Bi 4.12 t 0.14 29.2W 94.7 162t7 CCiR89-517 104G11 354301 K-Ar HQ 0.345 0.016 2.272 82.3 162*7 104W 348562 K-Ar Bi 6 980 t 0.020 46.357 88.4 183*6 104Gll W12 K-Ar WR 1.660t0.010 11.245 9.8 166*6 104W 352733 K-Ar Bi 5.9M i 0.200 42.932 81.4 17717 104G12 338140 K-Ar Hb 0.802 f 0.~1 5.W 92.7 177i6 lL"5 348562 Kdr HD 1.21 t0.w 8.995 91.7 182*7 104013 331062 K-Ar HQ 0.601 *O.w7 4.481 89.8 182f5 l04Gll 366699 U.Al HQ 0.567 i 0.003 4.W 90.7 2W*7 104G05 3411% n-M Hb 0773~0004 6.495 955 2Me7

Builetin 95 169 British Colwrbia

170 Geological Survey Brmch APPENDIX 13 URANIUM-LEAD ANALYTICAL DATA

Zircon fraction Wl. U Pb" 206pbb PbC 20BPba -2WPbd 207pbd ccfr. 207pbd 207Pb/206Pb (mg.) (ppm) (PP) '04Pb (pa) (%)235" 238" C~fl.~age '06Pb (Ma) Hazellon Group andesilicluff(Sample DBR-90.162)' A. N1 t74-105A 0.023 425 13 1298 14 6.8 0.03032 f 0.10% 0.2101 fO.26% 0.56 0.05027 f 0.23% 207.3 t 10.8 8. N1 t62-74 A 0.013 527 15 784 18 10.7 0.02687i0.14% 0.1982 f 0.51% 0.60 0.04980 f 044% 165.8 i 20.5 C. N1 +149A 0.010 35 1169 2198 10 11.1 0.02908 iO.11% 0.1995 f 0.21% 0.85 0.04978 f 0.16% 184.5 t 7.5 Hazellon Group flowbanded rhyolile. (Samde.. DBR-90717)1 A. M2 t4563 0.2 532 13 675 247 13.2 0.02369 f 0.15% 0.1632 iO.21% 0.70 0.04954 +0.15% 173f7 B. N2 +6?-100 0.5 107 3 851 141 12.1 0.02617i0.15% 0.1606 f0.2146 0.70 0.OM05t0.15% 197t7 C. M2 +8&1Do 0.4 325 9 996 228 12.0 0.02663i0.15% 0.1628f0.16% 0.63 0.04978 f 0.10% 185k5 0. N2 +10&350 1.3 491 13 334 1120 12.0 0.02611 f0.15% 0.1767f1.35% 0.43 0.04964 + 1.32% 178f15 E.NZ +10&350A 0.2 386 I1 1266 108 11.7 0.02747f0.15% 0.1878*0.17% 0.69 0.04957 f 0.08% 175f4 Cone Mounlaingranaliarile (Sample DBR-9MO)' A.+IO5 N1 A 0.w 537 18 1578 28 12.6 0.02905 i 0.1 0% 0.1993f0.17% 0.70 0.04976 f 0.13% 183.9 1; 5.9 B. N2 +105A 0.089 429 13 1657 42 11.4 0.02906 fO.OS% 0.1993f0.15% 0.77 0.04973 f 0.10% 162.6 f4.5 C.M2+149A 0.062 402 12 2480 16 13.5 0.02906 f 0.10% 0.1995f0.18% 0.70 0.04976f0.11% 183.9 f 5.3 D.N2t105149A 0.102 606 17 2597 42 11.6 0.02613 C 0.09% 0.1937k0.13% 0.62 0.04994 f 0.07% 192.1 i3.5 Limpoke quartrmonzcdiwile (Sample DBR-91-723)2 A. N2 +3W5 1.1 759 20 5108 269 13.8 0.02568f0.15% 0.1767f0.15% 0.99 0.04991 f 0.02% 191 f 1 B. N2 +45-80 1.7 486 12 4297 100 12.7 0.02525f0.15% 0.1736f0.16% 0.96 0,04986f 0.04% 188i2 C. N2 +60-100 1.8 422 11 3793 112 12.3 0.02615f0.15% 0.1799f0.22% 0.87 0,04991 *0.17% 191 f 6 0. N2 +100-125 1.9 410 11 3910 111 12.2 0.02606 fO.15% 0.1791 fO.22% 0.68 0.04985 f 0.16% 168 f 8 E. N2 +125350 0.6 304 8 3377 119 11.9 0.02569f0.15% 0.1767f0.15% 0.96 0,04989 f 0.03% 19oi2 F. N2 +145-350 0.4 398 I1 6104 47 12.6 0.02794fo.15% 0.1924f0.15% 1.00 0.04993 * 0.01% 192f1 Rugged Mountaindyke (Sample DBR-91-725)3 A. N2 +74-105 0.031 2206 86.6 IO7 1250 21.2 0.02643 * 0.36% 0.1819t2.22% 0.04991 f2.04% 191.0 f 95.0 B.N2 t105134.aB.N2 13190.010 46.3 524 46 23.2 0.02982f0.15% 0.2044 f 0.74% 0.04972 f 0.66% 181.7i30.9 C. N2 +74-105. a 0,011 993 344 474 40 25.0 0.02872 fO.12% 0.1984 f 0.65% 0,05011 f 0.58% 199.9k27.1 D. N2 +74-134. a 20710.010 69.0 398 1w 21.3 0.02901 *0.12% 0.2002 f0.72% 0,05004CO.65% 197.0i30.1

~ __ Brifish Columbia

172 Geological Survey Branch - Ministry of Employnenl and Inveslmenl

APPENDIX 14 LITHOGEOCHEMICAL. DATA - FIELDNO. NTS UTM (Zn09) SAMPLE DESCRIPTION Au Ag Cu Pb Zn As Sb - MAP EAST Ppm. NORTH ppm. Ppm.PPb ppm PPm' ppm DBR88-5-2 1WGLU 346050 6356750 RuUy argillite with 5-1 0% dis py. PO -20 1 36 16 380 3 1 DBR88-20 1WG06 350630 6548450 Limonitic.buff limestone <20 ~0.5 5 7 27 5 50.5 DBR88101 1WGM 3M1000 6357550 Quartzvein insiblone <20 <0.5 21 7 29 36 40.5 DBR88-107 1MM5 319ow 6367100 Fyilic quam vein in altered intrusion (F) 112 20 9 42 22 1 q0.5 DBR88-113-1 1WG05 322200 6365800 Quartz vein wilh 25% gal. cpy. py (F) e20 37 0.27% 2.30% 1.44% Cl 3 DBR88-113-2 1WG05 322200 6365800 Quam vein wilh 25% py (F) 730 66 181 760 950 54 2 DBR88-115 lWG05 322900 6365500 Fyilk qualtr vein in Emne granite BO <0.5 4 39 10 3 0.7 DBR88-1301 lWG05 348600 6351640 Finegrained marc rack wilh malachite (F) 97 2 620 5 440 7 0.6 C'BR88-1302 1WGO5 348600 6351640 Anered limestone wilh mt. py.cpy 58 0.5 0.31% 3 173 8 c0.5 DBR88-187 104- 361330 6359720 Mafic sandslone with pyritic Fe-carb vein 5 COS 154 3 66 9 5 DBR88-213 1WG06 361040 6354820Anered limestone with pyrite, 2 C0.5 20% 3 36 112 11 DBR88-215 1WG06 361090 6354440 Fe-carb anered limestone wlm py, atpr 1 1.5 232 3 35 232 260 DBR88-222-2 1WGM 360040 6350930 Fezarb alteredlimeslone abw faun 1 COS 92 3 55 7 2 DBR88-286-1 1MG05 348140 6371700 Quartz vein 154 6 126 19 15 39 0.9 DBR88-2863 1MG05 348140 6371700 Massive sulphide pod with ml. py 102 25 91 20 24 54 COS DBR88-288 1WG05 347830 6371430 PyrileqJartz zone in vobnics 226 0.8 14 14 7 8 3 DBR88-302-2 lWG06 357650 6375300 Fe-Carb vein with py, splr. gal 450 20 450 0.58% 3.50% 258 321 ClBR88-336 1MG05 320650 6366225 Slck clcpmlW in anered felsicin1 (T) 1 ~0.5 15 20 30 Cl 0.5 ClBR88-337 1WW5 320650 6366225 Slck ckpmltd in anered felsic in1(r) 1 275 75 18 103 Cl 0.5 C3BR88-338 1MG05 320650 6366225 Srct-allered felsic in1 (D) 7 7 1 28 24 30 cl 0.5 1WG05 320650 6366225 Srd-allered felsic in1 with 91-mltd slck (D) 4 c0.5 17 20 22

- Bullerin 95 I73 Brirish Columbia

- FIELD NO. UTM (Zn 09) SAMPLE DESCRIPTION Au Ag Cu Pb Zn As Sb EAST NORTH ppb ppm ppm’ ppm. ppm. ppm’ ppm

1MG12 33751 1 6400131 siliceous tuffwilh disseminated py. c2 C0.5 200 9 2.0 lMG12 338259 6399941 siliceous tuffwith disseminated py. c2 c0.5 ’IM... 4 0.7 lMG11 353660 6377330 cm-scale qzcb veinlets @ py. gal. sph. py, 43 45.0 0.86% 0.51% 2.0 CGR89-307-2 lMGll 353660 6377330 un-scale qzzb veinlets @ py, gal, sph. py, 136390 19.0 0.29% 27 0.7 CGR89-324 1MG12 349748 6378342 float: qz vein @ ep. hem. cpy. py, mal 7 3.0 0.73% 7 2.0 CGR89-337 1WGll 353071 6376673 Sikfied. chlorilked andeprich plutonic 5 c0.5 118 7 3.0 CGR89-341 1MGl1 354520 6376545 cb vng 8 hematiticlpolassicab in plut host c2 c0.5 A 7 0.7 CGR89-359 1MGll 351903 6381529 pyritic and chlorilicwallrack to dike swarm 10 ~0.5 68 10 ~0.5 1MG12 337371 63935m cb veining and veikbreccia e2 a5 17 2 c0.5 CGR8W11 1MG12 347667 8379730 siliciied andpolassically(?) anered plut rock 5158 2.0 28 267 3.0 CGR89-412 1WG12 347476 6379970 18 C0.3 121 15 CGR89-460 1MG12 346971 6389455 M-scale qz veinletwilh py 312 12.0 0.50% 15 2.0 CGR89481...... 1WG12 347824 6376597 soil sample from limonitic zone 21 <0.5 315 24 3.0 CGR89-492-2 1MG11 35801 1 6383849 sumqz veinlet @ mal. py, ep 18 <0.5 0.52% 2 2.0 1MGll 363564 6375622 noat: qz veinlet @ vfg chaMte(?). mai 560 22.0 1.8% 79 6.0 1MG12 340283 6393699 Fe carb and chalcedonlc qz vein-breccia e2 c0.5 72 5 7.0 1MG12 340283 6395699 qz andFe cab veining s2 C0.5 68 2 3.0 1MG12 339639 6393835 chalcedonic qzvng 8 limonite open space <2 C0.5 40 7 24.0 1MG12 339105 6394010 Fe carb ann & drwv~. az o~en. soace. fillina- c2

1MG12 347013 6385242 Owat: qz vein@ w 342 2.0~~ 0.12% 31 14.0 DER89298 lWGl1 354563 6379169 qzSakite vein @ qy.gal. py 856 37.0 2.5% 0.36% 0.7 DBR89-298DUF 1MG11 354563 6379169 qz-calcite vein @ cpy. gal. PY 2561 29.0 1.9% 1.7% 1.o DBR89-302 1WG11 354555 6379720 qz vein @ mal 3w 261.0 11.8% 4 20.0 DER89367 1WG12 339187 6395997 silicified host @ 2% disseminated py 167 cn~5 10 19 4.0 DBR89-367-2 1MG12 339187 6395997 qrzaldte veins in clay-anered volcanichost 86 c0.5 49 56 4.0 DBR89-367-3 104G12 339187 6395997 qzzalcite veins in clay-altered volcanichost 140 S0.5 10 9 2.0 DBR89382 104G12 349193 6383577 qz-Fe cb vein @ py 766 12.0 7 0.31% 8.0 DBR89-383 1WGl2 349343 6383521 disseminated py in anered volcanic breccia 38 4.0 203 0.11% 21.0 DBR89-384 1wG12 349343 6383521 qzcalcite vein @ gal. py 548 40.0 485 2.2% 55.0 DBR89-388 1WG12 349486 6383569 qzzakite vein @ py, gal 3 5.0 20 585 39.0 DBR89-397 1WG12 347156 6384568 float: limonitic. pyritic altered breccia 17 1.7 6 56 2.0 DBR89-398 1WG12 347157 6384569 float clay-altered corgbmerate 6 0.8 11 41 7.0 DBR8W08-2 1w12 347488 6382841 vein 6 2.0 68 58 47.0 MGU89-73 1WG11 359468 6378210 chlorilized mafictuff ‘2 2.0 46 5 .- 0.8 MGU8973DUP 1MG11 359468 6378210 chloritired mafic luff 62 2.0 47 5 52 6 0.6 MGU89-112-2 IWGH 3m73 6380466 UP lo 10% PYin hb qz diorite dike <2 0.8 120 5 57 1 c0.5 MGU89-115 1WG11 3MKxK( 6380002 up to 10% pyin hb qz diorite dike 56 0.8 246 5 S0.5 MGU89115DUf 1WG11 3”8 6380002 uplolO%pyinhbqzdioritedike 77 0.8 282 5 s0.5 MGU89-124 1WG12 340509 6382959 pyritic melavolcanic 15 0.8 43 5 3.0 MGU89-125 1WG12 340515 6383126 pyrik metavolcanic 3 0.8 53 5 2.0 MGU89-126 1WG12 340468 6383222 pyritic melavolcanic <2 0.8 85 17 2.0 MGU89-126DUf 1MG12 34wM1 6383222 pyritic melavolcanic 42 0.8 17 466 2.0 MGU89-141 1MG12 340370 6381134 pyritic siliceoustuff 3 0.8 6 17 1.0 MGU89-143 1MG12 340508 6380666 pyritic siliceousluff <2 0.8 15 23 1.0 MGU89-144 1WG12 340500 6380258 pyritic siliceoustuff 8 0.8 40 5 0.7 MGU89-144DUf 1WG12 340500 6380258 PyrW siliceous tuff 11 0.8 45 5 C0.5 MGU89-180-2 1MG12 334859 6387323 pyrilic andesite dike <2 ~0.5 134 12 0.6 MGU89-184 1WG12 334242 6386MB pyritic andesi dike 4 <0.5 52 5 31 43 1.o MGU89-189-2 104G12 333426 6386410 pyritic recrystallized limestone 14 1.3 199 38 c0.5 MGU8920P2 1WG12 333095 6385834 pyritic recrystallired limestone <2 c0.5 104 17 1.0 MGU89-238 1MG12 333400 6390208 pyritic melapelide 6 C0.5 0.10% 9 3.0 MGU89-252 1WG12 332081 6392931 pyritic hb. plagioclase porphyriticdike d2 C0.5.~. 35 10 .~ 0.6 MGU89-279-2 1MG12 327858 8391153 dacite tuff @ SlO%layer-paallel pyrite <2 <0.5 28 14 82 17 2.0 DBRW243 1MGW 361339 6349375 WrxlPGE of a gabbmlpridotite 3 c0.5 40 5 0.9 MGUW157-2 1WG05 341290 6556620 1 <0.5 34 3 2 MGUW224 1 c0.5 74 5 e0.5 MGU90.518 1WG12 340043 6383679 4198 3.7 578 7 5 MGU90.580-3 1MG05 339764 6371561 5 0.1 14 6 2 lNE9145 1MG13 322521 6403596 Pyritc sinstone 7 c5 47 12 loo 4 0.9 INE91-45-2 1WG13 322521 6403596 Pyritc siltstone c5 c5 25 12 23 11 1.1

I74 Geological Survey Branch - FIELDNO. NTS UTM (Zn 09) SAMPLE DESCRIPTION AU Ag Cu Pb Zn AS Sb - MAP EAST NORTH Ppm. PPm' PDm PPb PPm PPm' PPfll. JT191-50A 1WG13 322775 6426500 10 m thick rusty altered zone <5 C5 114 10 180 5 2.2 JT19140Adup 1MG13 322775 6426500 10 m thick rusty altered zone 6 C5 125 12 181 6 2.3 llgE91-50 1MG13 322846 6403450 Py"tcsilD1One 13 +5 19 34 29 MI 5 DBR91471 1WG13 325259 6424810 Fecarbqtr-py vein6 un wide c5 c5 56 12 85 140 56 C)BR91470 104G13 325387 6424854 F-rb.qtr-py veinlets(flaa1) <5 e5 59 6 53 1x0 99 DBR91459 1WG13 325456 6424876 Rusty pyrite in vuggYquarcr(fl0at) 22 G5 40 4 37 1100 110 JT191-19A 1WG13 327750 andesitealtered6408352chllep.F'yritic. 24 -5 416 22 105 9 3.2 JT191-17 1MG13 329270 6406695F-m.,malachite in quarizvetn 417 6 545 120 300 72 1.2 JT191-96C 1WG13 329906 6413005Limonitic dike c5 25 28 6 14 3100 410 JT191-14 1MG13 330309 Mo6770 Epaote.ma1. anerationalong faun 106 5 14G 12 38 c2 0.3 JT191-11 1MG13 330392 64W065 Rusty zone with qtr veins 8 pyrite e5 q5 128 6 9 c2 c0.2 C3BR91697-2 104G13 335641 6409541Malachiteinfilling of fractures 12 1.51%44 r;5 413 5 1.6 DBR91-530 1WG13 336983 6429701 Pyritictuff mudstone c5 45 35 12 200 7 2.9 DBR91-252-2 1WG13 339417 6407830Pyritc. anered volcanic mck 12 -5 112 8 55 7 1 DER91699 1WG13 340114 6408405 syeniteRusty. pyritrc 28 1;s. "-292 28" 366 1.2

.lT191-79 104G13 342037 6425680Alteredgranodiorite. mal. staining 647 22~~ 0.29% 10 54 89 1.8 DBR91-171 lWG13 342215 6412266Pyritic, altered syenite dike 7 <5 224 12 68 5 0.4 DBR91-3W 1WG13 342234 6428432 Limonilic zone C14 c5 69 6 41 26WO 870 .lT191-82 1MG13Limonitic 343652 6424797 diorite 8 c58 367 31 8 2.5 .lT191-55 104G13 343738 6425127 Rusty. altered quaflzveinr 2380 27 180 10 325 1700 a2 6422070 pvritic.imn carbonateanered r* 86 50 11 1.2 iNE91-81-3 1WG13 3455216410352 Bbtite. magnetite. pyrite. malachite 1810 C5 1.17% 18 3 117 0.3 INE91-78-3 1MG13 3457386409800 Aneredsyenite 11m 31 0.90% 36 153 ~2 2.6 DMU91-3 1WG13 6415602249636 Limoniteandepaoteanered rx 48 <5 21 22 54 250 5.5 DBR91-594 1WG13 3514886420711 Fe- cab. alteredvolcanic fad <5 c5 60 8 491 4

Buflerin 95 I75