Expansion & Collapse of the Cordilleran Ice Sheet during the Quaternary

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Under this award the PIs will reconstruct the glacial history of the southern limb of the Cordilleran Ice sheet using glacial-marine sediments off the coast of Vancouver Island, British Columbia. Glacial advances and retreats associated with corresponding paleoclimatic events are poorly documented in the Pacific Northwest prior to 15 Ka. The jumbo piston core MD02-2496 will be used to interpret the history of growth and decay of the Cordilleran Ice Sheet over the last 500 Ka (at ODP Site 888). As the North Pacific greatly affects the climate (including the jet stream) downwind across North America, data obtained from this study should advance ability to model climate, to interpret glacial geomorphology and calculate continental denudation rates. Knowledge of when the British Columbian shelf was ice covered and when iceberg discharge occurred will test the feasibility of the migration route of early humans attempting to occupy the American continent via the North Pacific coastal route. The PI will examine particle size and sediment fabric within a jumbo piston core (MD02-2496) and at ODP Site 888 to determine ice sheet growth and decay in the region. At the same time high quality 14C dates and local sea surface temperatures will be generated based on planktonic foraminiferal d18O. Benthic d18O values will be employed to resolve changes in global ice volume.