The Sedimentary Legacy of a Palaeo-ice Stream on the Shelf of the Southern Bellingshausen Sea: Clues to West Antarctic Glacial History during the Late Quaternary

• Published in: Quaternary Science Reviews
• Main Authors: Hillenbrand, C.-D., Larter, R. D., Dowdeswell, J. A., Ehrmann, W., Ó Cofaigh, C., Benetti, S., Graham, A. G. C., Grobe, H.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Digital Commons @ University of South Florida 2010
• Subjects: Life Sciences; Antarctic; Antarctic Peninsula; Bellingshausen Sea; The Antarctic; West Antarctic Ice Sheet; West Antarctica; Antarc*; Antarctica; Ice Sheet; Ice Shelf; Sea ice
• Online Access: https://digitalcommons.usf.edu/msc_facpub/1537; https://doi.org/10.1016/j.quascirev.2010.06.028

A major trough (“Belgica Trough”) eroded by a palaeo-ice stream crosses the continental shelf of the southern Bellingshausen Sea (West Antarctica) and is associated with a trough mouth fan (“Belgica TMF”) on the adjacent continental slope. Previous marine geophysical and geological studies investigated the bathymetry and geomorphology of Belgica Trough and Belgica TMF, erosional and depositional processes associated with bedform formation, and the temporal and spatial changes in clay mineral provenance of subglacial and glaciomarine sediments. Here, we present multi-proxy data from sediment cores recovered from the shelf and uppermost slope in the southern Bellingshausen Sea and reconstruct the ice-sheet history since the last glacial maximum (LGM) in this poorly studied area of West Antarctica. We combined new data (physical properties, sedimentary structures, geochemical and grain-size data) with published data (shear strength, clay mineral assemblages) to refine a previous facies classification for the sediments. The multi-proxy approach allowed us to distinguish four main facies types and to assign them to the following depositional settings: 1) subglacial, 2) proximal grounding-line, 3) distal sub-ice shelf/sub-sea ice, and 4) seasonal open-marine. In the seasonal open-marine facies we found evidence for episodic current-induced winnowing of near-seabed sediments on the middle to outer shelf and at the uppermost slope during the late Holocene. In addition, we obtained data on excess 210Pb activity at three core sites and 44 AMS 14C dates from the acid-insoluble fraction of organic matter (AIO) and calcareous (micro-) fossils, respectively, at 12 sites. These chronological data enabled us to reconstruct, for the first time, the timing of the last advance and retreat of the West Antarctic Ice Sheet (WAIS) and the Antarctic Peninsula Ice Sheet (APIS) in the southern Bellingshausen Sea. We used the down-core variability in sediment provenance inferred from clay mineral changes to identify the most reliable AIO ...