HR: 0830h
AN: PP31B-0264    [PDF]
TI: Sedimentation Processes Along the Continental Margin of the Western Bellingshausen Sea, West Antarctica
AU: Gohl, K
EM: kgohl@awi-bremerhaven.de
AF: Karsten Gohl, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, 27568 Germany
AU: * Scheuer, C
EM: cscheuer@awi-bremerhaven.de
AF: Carsten Scheuer, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, 27568 Germany
AB: Since the beginning of glaciation of West Antarctica, changes of glacial and interglacial periods affect the sediment supply across the shelf and onto the deep sea. Along the slope and rise of the continental margin of the Antarctic Peninsula, Cenozoic sediments were deposited which development was influenced by ice sheet fluctuation and mass transport processes. Thus, both the sediment stratigraphy and the physiography of the sea floor reflect the history of the West Antarctic ice sheet as well as processes that transport, erode and deposit sediment along the outer shelf, slope and rise of the continental margin. We present interpretations of multichannel seismic reflection data produced along and across the sparsely investigated continental rise of the western Bellingshausen Sea. This new seismic line links previously data sets of the eastern Bellingshausen Sea and the Amundsen Sea and contributes to a better understanding of the glacial-marine sedimentation processes along the West Antarctic margin. We could identify three sedimentary units, named Unit 1, 2 and 3. The lowermost Unit 3 is characterised as "Low-deposition Stage", representing the pre-glaciation stage. Unit 2 seems to reflects the onset of the glaciation on the continental shelf and can be termed as "Transition Stage". The uppermost Unit 1 is made of terrigenous sediment material transported by shelf ice across the shelf edge. The correlation with a profile orientated perpendicular to the slope shows that the boundary between the units 2 and 1 coincides with the base of a sediment wedge that consists of strong prograding shelf sequences, a strong evidence for shelf ice deposits. Thus, the boundary between units 2 and 1 indicates the advance of shelf ice up to the shelf edge, where transported sediment material was deposited. The onset of this advance along the margin of Antarctic Peninsula occurred approximately in the mid to late Miocene (about 5-8 Ma). However, an exact dating of the onset along this margin is difficult due to the far distance to the closest ODP Drill Sites 1095 and 1096.
DE: 1620 Climate dynamics (3309)
DE: 3025 Marine seismics (0935)
DE: 4540 Ice mechanics and air/sea/ice exchange processes
DE: 4558 Sediment transport
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting