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TitleStudy of glacial flows and associated sediments: the case of Amaruq, Nunavut
AuthorBoulianne-Verschelden, N; de Bronac de Vazelhes, V; McMartin, I; Beaudoin, G; Côté-Mantha, O; Simard, M
SourceGAC-MAC 2017; Geological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Programs with Abstracts vol. 40, 2017 p. 38
LinksOnline - En ligne
Alt SeriesEarth Sciences Sector, Contribution Series 20160447
PublisherGeological Association of Canada
MeetingGeological Association of Canada-Mineralogical Association of Canada Joint Annual Meeting 2017; Kingston, ON; CA; May 14-18, 2017
Mediapaper; on-line; digital
File formatpdf
Subjectsgeological surveys; mineral distribution; mineral exploration; ice sheets; ice movement; ice flow; sediment dispersal; till deposits
ProgramRae Province, Chantrey-Thelon, GEM2: Geo-mapping for Energy and Minerals
AbstractThe Amaruq project is located in Nunavut 60 km northwest of the currently operating Meadowbank gold mine. This region has a significant mineral potential but the basement rock is largely covered by till, thus furthering our understanding of glacial dispersal processes is essential for efficient exploration in the area. This study is on the understanding of the ice-flow history and surficial geology mapping of the Quaternary deposits at regional (1: 50,000) and detailed (1: 10,000) scales, both centered on the gold deposits at Amaruq. The study area is located about 100 km northwest of the last position of the Keewatin Ice Divide.
During the last glaciation, the Laurentide Ice Sheet covered the study area until the ice disappeared approximately 6,000-7,000 14C years ago. As a result, the area is extensively covered by various types of glacial deposits. The predominant surficial deposits are bouldery sandy till veneers, commonly forming small ridges perpendicular to ice flow, thick silty till blankets in streamlined landforms or plains, and five glaciofluvial systems containing esker ridges, hummocks, diamictons, kames and outwash plains. The thick silty till blankets appear to cover the sandy till veneers.
Previous reconnaissance-scale mapping indicates a main north-northwest regional ice-flow direction. In the study area, four sets of ice-flow directions were recognized based on the detailed mapping of striations, grooves and roches moutonnées. The oldest, oriented towards the NNW (N345°), is the dominant direction and is responsible for most of the glacial moulding of the landforms. The second and third ones are oriented respectively at N325° and N308° and did not have a significant influence on the orientation of the landforms. The fourth ice-flow set is found only locally along glaciofluvial systems and indicates late ice flows towards esker ridges.
A preliminary pebble count was done by ODM Laboratories on 10-kg till samples collected from frost boils. The results show that the sandy till veneers material has a major local component derived from the underlying bedrock. The bouldery sandy till veneer shows a sharp change in pebble composition across the underlying lithological boundaries in bedrock. The lithological package hosting the Amaruq mineralized zones is dominated by ultramafic to intermediate volcanic and sedimentary rocks, whereas the dominant lithologies up-ice of mineralization are essentially of granitic composition. The pebbles of the thick silty till blankets over and down-ice of the mineralized zones are granite-dominated even if the lithologies beneath are of the volcanic and sedimentary origin.
Summary(Plain Language Summary, not published)
This poster presents an overview of the 2016 field work completed on the Amaruq gold exploration project in central mainland Nunavut on the surficial geology of the mineralized zones. The interpretation of the glacial history and surficial geology mapping as well as targeted till and mineralized bedrock sampling form part of two MSc thesis research projects to develop till geochemistry and indicator mineral methods for gold exploration in areas underlain by permafrost. The Geological Survey of Canada is involved in co-supervising the student within the Chaire de recherche industrielle CRSNG¿Agnico Eagle en exploration minérale at Laval University. The study is part of the GEM-2 Thelon-Chantrey Rae Project and the findings will help improve mineral exploration methods in glaciated terrain.