The Record of Antarctic Environment Preserved in Deep Sea Sediments: Critical Times of Climate Change

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Rea OPP 9527067 Abstract This award supports a project to define the paleoclimatic variability during times of important climate change on Antarctica, in the latest Cretaceous and Paleocene, late Eocene and early Oligocene, and the early Pliocene. Preliminary data suggest that the Maastrichtian and possibly Paleocene environment of Antarctica was dry enough to permit generation of sufficient dust to form an important component of the sediments surrounding the continent. This research will determine if and when this semi-arid climate did exist on Antarctica and when it was superseded by more moist conditions. The transition to fluvial and hemipelagic dominated erosional processes may shed light on the initial formation of glaciers in the Antarctic hinterland. At the time of the Eocene/Oligocene boundary, changing sediment accumulation rates and the relative proportions of hemipelagic and ice-rafted material will provide information on when the Antarctic ice sheet became well-established, effectively shutting off the supply of fluvial sediment to the Southern Ocean. And finally, any significant change in the ice sheet configuration during the early Pliocene should be readily observable in the concomitant changes in the nature and rates of terrigenous sedimentation. To accomplish these goals, this project will examine the terrigenous component of deep sea sediments of the Southern Ocean. These materials contain a dual record of the environment of Antarctica and of the sedimentary transport processes. Techniques of mineral grain extraction, grain-size analysis, magnetic fabric determination, geochemical characterization, and flux calculation, all of which have proven diagnostic in the interpretation of paleoclimatic and paleoceanographic conditions, will be applied within this project to unravel the history of environmental change on the Antarctic continent.