Frank O. Nitsche

Lamont-Doherty Earth Observatory
of Columbia University
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Sedimentation processes in the Bellingshausen Sea and their variations along the continental margin

F.O. Nitsche, A. Cunningham, R.D. Larter and K. Gohl

Previous geophysical studies of southern-hemisphere glacial margin sedimentation have focussed on a few key areas of Antarctica (e.g. the Antarctic Peninsula, Prydz Bay, Wilkes Land margin, and the Weddell and Ross Seas). These investigations have shown diverse patterns of sediment deposition on the Antarctic continental shelf, slope and rise, which suggests regional variability in the sedimentation processes producing these deposits. In this study, we present multi-channel seismic reflection profiles (totalling 2700 line-km) and bathymetry data acquired across a remote and poorly surveyed part of the Antarctic continental margin in the Bellingshausen and Amundsen Seas. These data were obtained by the British Antarctic Survey (BAS) and the Alfred Wegener Institute for Polar and Marine Research (AWI) between 1992 and 1995, and incorporate the first digitally-recorded seismic reflection profiles crossing this part of the margin. This new information has been combined with published data, and used to interpret sedimentation processes in this region. Between 72° and 105°W, seismic reflection profiles show significant longitudinal variations in sediment input from the shelf to the upper slope. At greater depth, debris flows, turbidity flows and bottom currents control the further transportation and deposition of sediment. Variation in the style of sedimentation on the continental rise reflects the relative contribution of these different processes along the margin.

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Frank Nitsche - last update 9/27/2005