D and Deuterium Excess in the GISP2 Ice Core

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This award is for support to continue measurements of deuterium on samples from the Greenland Ice Sheet Project Two (GISP2) ice core. The values of deuterium measured on the GISP2 ice core samples will be used to reconstruct and interpret the temperature history recorded in the core. Deuterium excess values will also be calculated in order to determine the climate conditions at the oceanic moisture source. This work will be coordinated with the group from the University of Washington that is measuring oxygen isotope ratios on the ice core. Work to date suggests that records of pressure (North Atlantic Oscillation) and temperature (Jakobshave-Oslo seesaw) oscillations are recorded in the deuterium and deuterium excess values. Values of deuterium excess during the last glacial period show sharp changes at the times of some, but not all, of the massive fluxes of icebergs into the North Atlantic ocean (Heinrich Events). Major questions to be addressed include the nature of rapid climate changes seen in many of the climate proxies measured in the core, the existence of modes of climate as reflected by preferred states of the climate proxies, and the importance for the climate record of differential thinning and thickening of layers, as well as possible folding and faulting of the near basal ice.