The Effect of Deglacial Meltwater Processes on Kimberlite Indicator Mineral Concentrations in Glacial Sediments



Patrick DesRosiers –



P.D. DesRosiers – Simon Fraser University, Burnaby, BC, Canada
B.C. Ward – Simon Fraser University, Burnaby, BC, Canada
D. Sacco – Palmer, Vancouver, BC, Canada
B. Elliott – Northwest Territories Geological Survey, Yellowknife, NT, Canada



The purpose of this project is to quantify the effects of deglacial meltwater on kimberlite indicator mineral concentrations in meltwater corridor sediments. The study area is located 100 km west of Lac de Gras, NWT. It contains subglacial meltwater corridors and related landforms, unmodified glacial sediments and has diamond potential. Meltwater corridors are characterized by glaciofluvial sediments such as eskers, discontinuous sand and gravel veneers, enigmatic hummocks of sandy diamicton and exposed rock. Till dominates in intervening areas. The surficial geology was interpreted at a scale of 1:15 000 using 3D digital mapping software (Summit EvolutionTM). Fieldwork focussed on calibrating the interpretations of surficial materials, measurement of ice flow indicators and sampling of glacial sediments. Ongoing sample analysis includes granulometry and clast lithologies, indicator mineral recovery, and matrix and indicator mineral geochemical analysis. Grainsize analysis reveal that till generally has more silt and clay than meltwater-affected sediments within the meltwater corridor, which can affect the normalization of analytical results. There is variability in KIM concentrations along a transect of samples that include unmodified till and meltwater affected sediments. These results are discussed in terms of drift prospecting and meltwater-related landform genesis.

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