Collaborative Research: Do Holocene Variations In Arctic Sea Ice And Greenland Icebergs Drifting Through Denmark Strait Reflect Natural Cycles?

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Historical observations and theory suggest the importance of the extent and duration ofdrift ice on the Climate System through changes in the Hemispheric albedo and the impact of freshwater export from the Arctic Ocean and Greenland Ice Sheet on the Thermohaline Circulation. Funds are provided to develop 50-100 yr resolution records of changes in sea ice export from the Arctic Ocean and iceberg transport from tidewater ice streams of NE Greenland that reach the Denmark Strait and to develop a detailed history of ice-rafted debris (IRD) over the last 12,000 cal yr BP. Denmark Strait is believed to be a critical area for study as it lies at the boundary between the southward export of Polar and Arctic waters and the northwestern limb of the North Atlantic Drift in the form of the Irminger Current. The research will explore a sources-to-sink model along the ENE/E Greenland shelf and across the Denmark Strait using sediment characteristics to document spatial and temporal changes in composition in a series of well-dated, high-resolution cores from either side of the Denmark Strait and along the NE Greenland shelf. This information will be used to infer changes in the transport of sea ice through the Denmark Strait.Given the ongoing observations of changing sea ice character in the Arctic, changes in the flux of sea ice into the Greenland-Norwegian Seas and the North Atlantic Ocean, and possible acceleration of ice loss from the Greenland Ice Sheet through iceberg calving, a better understanding of how these processes varied in the past will help inform projections of future climate variations. This project will develop data sets that contribute to that understanding.