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TitleGeochemical and mineralogical dispersal in till from the Mount Polley Cu-Au porphyry deposit, central British Columbia, Canada
LicencePlease note the adoption of the Open Government Licence - Canada supersedes any previous licences.
AuthorHashmi, S; Ward, B; Plouffe, AORCID logo; Ferbey, T; Leybourne, M
SourceGeological Survey of Canada, Open File 7589, 2014, 1 sheet, Open Access logo Open Access
LinksCanadian Database of Geochemical Surveys, downloadable files
LinksBanque de données de levés géochimiques du Canada, fichiers téléchargeables
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
File formatpdf
ProvinceBritish Columbia
NTS93B/07; 93B/08; 93B/09; 93B/10
AreaQuesnel Lake; Fraser River
Lat/Long WENS-121.9167 -121.4167 52.6667 52.4167
Subjectsgeochemistry; economic geology; surficial geology/geomorphology; metallic minerals; mineralogy; dispersal patterns; sediment dispersal; porphyry deposits; porphyry copper; glacial deposits; tills; till analyses; till geochemistry; drift prospecting; drift deposits; ice flow; ice movement directions; glacial history; mineralization; Mount Polley Mine; Cenozoic; Quaternary
Illustrationslocation maps; photographs; photomicrographs; plots; flow charts
ProgramTargeted Geoscience Initiative (TGI-4) Intrusion/Porphyry Ore Systems
Released2014 03 02
AbstractMount Polley Mine is an alkaline, silica-under saturated Cu-Au porphyry deposit owned by Imperial Metals Ltd. It is located 8 km southwest of Likely, within the Interior Plateau of British Columbia. This region was glaciated several times during the Quaternary and is predominantly covered by till. This makes it an ideal site to develop drift prospecting exploration methods for detecting buried mineralization. Glaciers are dynamic, eroding bedrock, and transporting and depositing the resulting debris as till in the direction of ice movement. If a glacier erodes mineralized bedrock, the resulting till will be enriched in elements and minerals derived from the mineralization. Porphyry mineralization and the associated alteration zones are spatially extensive, which may result in large dispersal trains in till. The objective of this research is to characterize the geochemical and mineralogical composition of till in the Mount Polley region in order to identify key indicators of porphyry mineralization in till, benefiting future exploration for porphyry deposits in areas of thick drift cover. This research is funded by the Geological Survey of Canada's Targeted Geoscience Initiative (TGI-4) program. Dominant ice flow in the Mount Polley region is to the northwest with an earlier west-southwestward flow. During the 2012 and 2013 field seasons, 87 till samples were collected up-ice, overlying and down-ice from the deposit based on these flow measurements. Elements and minerals associated with the mineralization show elevated content near the deposit, which progressively decreases towards the northwest (or down-ice direction). These include copper, silver (in the 2 ?m fraction) and gold (in the 63 ?m fraction), up to 1548 ppm, 503 ppb and 90.2 ppb, respectively. Gold grain content of up to 87 grains per 10 kg is observed in the silt-fine sand fraction. In the heavy mineral concentrates (s.g > 3.2), apatite (up to 0.5%), chalcopyrite (up to 98 grains per 10 kg), and epidote (up to 90%), observed in the 0.25 - 0.5 mm fraction. Gold grain, chalcopyrite, and epidote are excellant indicators of Mount Polley mineralization. However, apatite may not be a suitable indicator of Mount Polley mineralization in till.
Summary(Plain Language Summary, not published)
The Targeted Geoscience Initiative (TGI-4) is a collaborative federal geoscience program that provides industry with the next generation of geoscience knowledge and innovative techniques to better detect buried mineral deposits, thereby reducing some of the risks of exploration. We need to find new methods for discovering mines where rocks are covered with glacial sediments: loose material (gravel, sand and clay). These methods are essential for the discovery of the next generation of mines in Canada. This poster presents one way of detecting metals associated with intrusive rocks like granite. We have identified mineral grains the size of a sand grain which are indicative of the potential presence of an economic metal deposit. The presence of these minerals in glacial sediments suggests that metals of economic potential might be found in rocks underneath the sediments.

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