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TitleDrift prospecting applied to Iron Oxide Copper Gold exploration in the Great Bear Magmatic Zone, Northwest Territories, Canada
AuthorNormandeau, P X; McMartin, I; Paquette, J; Corriveau, L
SourceGeohydro 2011, Joint meeting of the CANQUA and International Association of Hydrogeologists, abstracts volume; 2011 p. 1
LinksOnline - En ligne (Full program/Programme complet, PDF 150 MB)
Alt SeriesEarth Sciences Sector, Contribution Series 20100335
MeetingGeohydro 2011, Joint meeting of the CANQUA and International Association of Hydrogeologists; Quebec City; CA; August 28-31, 2011
Mediapaper; digital
ProvinceNorthwest Territories
Subjectseconomic geology; surficial geology/geomorphology; drift prospecting; drift deposits; iron oxides; copper; gold; mineralization; exploration; exploration methods; glacial deposits; tills; Great Bear Magmatic Zone; Cenozoic; Quaternary
ProgramGEM: Geo-mapping for Energy and Minerals, Iron-oxide Copper-gold (IOCG) / Multiple Metals - Great Bear Lake (NWT)
AbstractAs part of Canada's Geomapping for Energy and Minerals (GEM) Program, an applied Quaternary research activity under the IOCG-Great Bear Project was undertaken in the Great Bear Magmatic Zone (GBMZ) to provide a practical guide to geochemical and indicator mineral exploration for Iron Oxide Copper-Gold (IOCG) deposits in glaciated terrain. Initial work was completed in 2007 as an orientation study around the NICO Co-Au-Bi deposit, interpreted as a magnetite-group IOCG deposit. Recent field work, completed in 2009 and 2010, began the second phase of this project. Bedrock (n=111) and till (n=102) samples were collected up-ice, proximal to, and down-ice from mineralization, host hydrothermal systems and least altered bedrocks. Detailed sampling was completed in the vicinity of the Sue-Dianne Cu-Ag-Au hematite-group IOCG deposit and near additional showings thought to be parts of large polymetallic IOCG systems within an IOCG-porphyry-epithermal continuum across the GBMZ. Characterization of the non-ferromagnetic indicator mineral physical properties, minor and trace element composition, and determination of till matrix geochemistry will serve to evaluate preservation and/or modification of useful IOCG deposit mineralization or alteration signatures in glacial sediments. This work forms part of a PhD research project at McGill University and represents a collaborative effort between the University and the Geological Survey of Canada.
Striations, roches moutonnées and crescentic fractures indicate a predominant ice-flow direction varying from 250° in the southern part of the GBMZ to 280° in the north. Traces of older ice-flows were also recorded across the GBMZ but do not display any consistent relative chronology. The extent of glacial dispersal will be assessed using local ice-flow indicators and till composition (matrix and clasts).
Preliminary results indicate the presence of chalcopyrite, apatite, pyrrhotite, andradite, Mn-epidote, bornite, allanite, ferroactinolite, fluorite and gold in various concentrations within the indicator mineral fraction (0.25-2 mm; SG>3.2). Surface bedrock samples collected at the Sue-Dianne deposit contain chalcopyrite, malachite, bornite, allanite, gold and hematite/magnetite. Till collected over or immediately down-ice of Sue-Dianne contains a number of apatite and tourmaline grains, while gold, chalcopyrite, gahnite and Mn-epidote are present in low concentrations. SEM examination revealed trace amounts of iron oxides in gahnite, apatite, tourmaline and andradite grains (0.25-0.5 mm) from till samples collected down-ice of Sue-Dianne and other showings. Some chalcopyrite grains (0.25-1 mm) are found in association with specular hematite. Further examination of selected grains, electron microprobe analysis and LA-ICP-MS analysis will help to develop criteria that contribute vectors to IOCG deposits.