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The varying nature and thickness of glacial sediments affect the characteri...
The varying nature and thickness of glacial sediments affect the characteristics of glacial transport in the Amaruq gold deposit area in Nunavut, Canada. To help evaluate the deposit signature, glacial sediments were collected in frost boils along transects parallel to the main ice flow direction. A complementary detailed geochemical drift exploration dataset and a new Quaternary map were also used to define the geometry of the mineralized debris dispersal trains. Principal Component Analysis identifies a gold mineralization signature associating As, Ag, Au, Cu, Pb, Sb, W, S, Fe and Zn and its mafic-BIF host rock. This signature, similar to lode gold geochemical signatures, follows a general NNW dispersal trend, in agreement with the predominant regional and local ice-flow indicators. In a zone covered by thick till within streamlined landforms and characterized by distal provenance, the dispersal train shows a significant distance for the first indicator to appear at surface down-ice of the known mineralization (~1 km lag). Results from this area also show a lower intensity of deposit signature compared to other mineralized dispersal trains located in thin till forming small transverse moraine ridges and characterized by a local provenance and a ~300 m lag. High counts of scheelite and pristine-shaped gold grains are found down-ice of mineralization and their distribution are in general agreement with the nature of the dispersal trains defined by the till geochemistry. Our results strengthen the use of PCA and indicator minerals combined with an understanding of ice flow dynamics to map deposit signatures and efficiently guide mineral exploration during glacial sediment surveys at local scales.
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