Interior Plateau Geoscience Project: Summary of Geological, Geochemical and Geophysical Studies
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Ministry of Employment and Investment Energy and Minerals Division Geological Survey Branch INTERIOR PLATEAU GEOSCIENCE PROJECT: SUMMARY OF GEOLOGICAL, GEOCHEMICAL AND GEOPHYSICAL STUDIES Edited by Larry J. Diakow, P.Geo., John M.Newel1, P.Eng. Geological Survey of Canada BC Geological Survey Branch Open File 3448 Paper 1997-2 v> Ministry of Employment and lnvesfment Energy and Minerals Division Geological Survey Branch INTERIOR PLATEAU GEOSCIENCE PROJECT: SUMMARY OF GEOLOGICAL, GEOCHEMICAL AND GEOPHYSICAL STUDIES Edited by Larry J. Diakow, P.Geo., John M.Newel1, P.Eng. Geological Survey of Canrtda BC Geological Survey Branch I Open File 3448 Paper 1997-2 Canadian Cataloguing in Publicatton Data Main enhy under titlee: Interior Plateau geoscience project :summary of geological, geochemical andgwphysical studies (Paper ; 1997-2) Issued by Geological Survey Branch. Includes bibbographical references: p. ISBN 0-7726-3208-1 1. Geology, Economic - British Columbia - interior Plateau Region. 2. Geology - British Columbia - Interior Plateau Region. 3. Geochemistry - British Columbia - Interior PlateauRegion. 4. Geochemical prospecting - Victoria British Columbia - Interior Plateau Region. 5. Mines and British Columbia mineral resources - British Columbia - Inten01 Plateau Canada Region. I.Newell, J.M. (John M.). 11. Diakow, LanyJames, 1955- . 111. British Columbia..Ministry of Emplopat and Investment. IV. British Columbia. Geological Swqbranch. March 1997 V. Titlc Vl. Series: Paper (British Columbia. Minisky of Employment and Invesment) ; 1997-2. QE187.157 1997 557.11'82 C97-96W86-3 Mlnisby of-b@ and ~n- TABLE OF CONTENTS LJ. Diow: Introduction ........................................ 1 D.E. Kerr and V.M. Levson: Drift Prospecting LJ. Diow, I.C.L. Webster,T.A. Richards Activities in British Columbia' An and H.W. Tipper: Geology of the Fawnie Overview with Emphasis on the Interior and Nechako Ranges, Southern Nechako Plateau ........................................................... 159 Plateau, Central British Columbia (931;2,3, SJ. Cook: Regional and Property-Scale 6,7) ...................................................................... 7 Application of Lake Sediment P. Metcalfe, T.A. Richards, M.E. Vieuve, Geochemistry in the Search for Buried Deposits J.M. White and CJ. Hikson: Physical Mineral in the Sonthern Nechako and Chemical Volcanology of the Eocene Plateau Area, British Columbia 175 Mount Clisbako Volcano, Central British (93C, Fi, F, K, L) ............................................. Columbia ........................................................... 31 C.E. Dm:Biogeochdcal Surveys in the Interior Plateau of British Columbia 205 P. Sehhha and J. Riddell: Geology of the .............. Tatlayoko Lab - Beece Creek Area (92N8, M.E. Best, V.M. Levson and LJ. Diilkow: 9, 10; 92015, 6, 12) ........................................... 63 Eleemmagnetic Mapping in Drift Covered Regions of the Nechako Plateau, British P.S. Mustard and P. van der Heyden: Columbia 225 Geology of Tatla Lake (92Nl15) and the ......................................................... East Half of Bussel Creek (92N114) Map D. Teskey, P. Stone, P.S. Mustard and P. Areas ................................................................ 103 Metealfez High-Resolution Regional Aeromagnetic Swey - Ioteiior Plateau V.M. Levson and T.R Giles: Quaternary British Columbia ............................................. 221 Geology and Till Geochemistry Studies in the Nechako and Fraser Plateaus, Central RA. Lane and T.G. Sdmete~:A Review of British Columbia (93Ul,8,9, 10; F/2,3,7; Metallic Minerakation in the Interior U16;W1) ..................................................... lZ3 Plateau, Central British Columbia (Parts of 93B, C and F).................................................. 237 A Plode: Reconnaissance Till Geochemistry on the Chilcotin Plateau (92015 and 12) ........ 147 Paper 1997-2 iii Ministry of Employment andInveSrmenr INTRODUCTION By LJ. Diakow, Britiih Columbia Geological Suwey The Intenor Plateau (Figure 1) is one of the most ders the plateau in the southwest. They focused on areas promising, yet least explored areas of high mineral poteu- with known deposits, working outwards into less well- tial in British Columbia In 1992, the Geological Survey of known prospective geology. Two mapping programs, in Canada and British Columbia Geological Survey initiated the southernNechakoRiver and northeastern AnahimLake the Interior Plateau Project, operating under the auspices map areas. were conducted where epithennal precious of the Mineral Development Agreement (1991-1995). The metal and porphyry copper-molybdenum prospects are ex- objectives of the project were to improve understanding of posed in windows through the younger Neogene cover. the geology and mineral deposits, test and develop explo- Other mapping in the vicinity of the Fish Lake deposit and ration techniques suited fordrift-covered terrain, and pro- further to thenorth in the CharloaeLake, Junker Lake (NTS vide the best possible mineral potential assessment for the 92N), Tatla Lake and Bussel Creek (NTS 93C) map areas Interior Plateau region. The project brought together a team encompassed prospective terrain for porphyry style depos- of 26 scientists, some of whom provided ancillary informa- its along the eastern margin of the Coast Belt and in the tionfor core programs that includedmineraldepositstudies structurally complex zone marking the western margin of (Figure 2). bedrock and surfcia1 mapping, till and lake the Intermontane Belt. The results of these program pro- sediment geochemistry, and hiogeochemistry, airborne vide an updated stratigraphic and structural framework for magnetic, gamma-ray spectrometric and electromagnetic ongoing mineral exploration. surveys (Figure 3). The Interior Plateau's dense forest, The Interior Plateau contains a number of present and blanket of glacial sediments and Neogene volcanic rocks past-producing mines, including Blackdome. Gibraltar, have hidden much of the older bedrock and hitherto hin- Endako and Equity Silver, that all lie outside the region dered exploration. This volume contains summary reports studied. A survey of mineral occurrences in the northern for these programs. pm of the Interior Plateau was carried out in order to Mapping programs were carried out in areas of varied document their characteristics and to establish local geo- topography fromlow-lying plateau te~~ain,typical of much logic setting and controls. These data are integrated in a of the Interior Plateau, to mountainous terrain which bor- conceptual model. A high-resolution aerornagnetic survey covering fifty- nine 150 COO-scale map sheets in the Interior Plateau is integral to better understanding of regional trends of stra- tigraphy, structure and mineral deposits in sreas of poor outcrop. In addition, three multiparameter airborne geo- , !F 1 TS(CIUt i I Mineral Deposit Studies Figure 1. Location of the Interior Plateau and physiographic subdivisions and tectonos!xatigraphicterranes in south and cenhai Figure 2. Location of metallic mineral occurrences studied in the Bntlsh Columbia southern NecbAo Plateau. Brifish Columbia Bedrock Mapping Aeromagnetic Suwey Figure 3. Location of gmsciena: p10pms in the Interior Plateau region. 2 Geological Survey Branch Minirrry ofEmptoymenr and Investment physical surveys, centred on the Fish Lake, Cllsbako and exploration applicable to the Interior Plateau. Three small Wolf deposits, acquired gamma-ray spectrometric, mag- regional lake sediment geochemical surveys were com- netic and VLF-EM data at an elevation approximately one pleted in the Nechako River and the Fort St. James third of that of the regional aeromagnetic survey. The study (NTS 93K) map areas, where Mesozoic and Cenozoic was designed to test the application of these techniques in rocks host a variety of mineral deposits. The program, the vicinity of known prospects with differing parameters based on prior orientation studies, determined background such as host lithology, minedkation and alteration. De- levels for pathfinder elements, corroborated previous lake tailed ground electromagnetic surveys were used locally to sediment anomalies, and outlined new areas for iiniher substantiate differences in till thickness and the location of exploration. Two biogeochernical surveys were carried out buried intrusive contacts. over the Fish Lake porphyry and Clisbako epithermal de- Studies of glacial deposits, supplemented by geo- posits to assess the potential of plant species for detecting chemical analysis of till samples were conducted in the different types of concealed mineral deposits. Anahlm Lake (NTS 93C) and Nechako River (NTS 93F) Contributions of the Interior Plateau Project have sig- map areas and, in the Mount Tatlow and Elkin Creek map nificantly improved our understanding of geology in this areas (NTS 920) in the sonthern part of the Fraser Plateau. region. Integration of geological studies from the different The main objectives of these projects were to map the disciplines has led to new mineral discoveries and identi- distribution of Quaternary deposits, determine glacial his- fied additional exploration targets. Advances have also tory, identify geochemically anomalous areas, refine mod- been made in development of exploration techniques spe- els of glacial dispersal and develop methods of drift cifically suited to this part of the Canadian Cordillera. Paper 1997-2 3 .