Sedimentation on the Weddell Sea continental margin and Abyssal Plain, Antarctica
Fisco, Mary Pamela P.
Anderson, John B.
Master of Arts
Abyssal sediments collected in piston cores were examined to determine sediment distribution patterns and active sedimentary processes in the Weddell Sea. Pelagic, hemipelagic, debris flow, and turbidite deposits were identified and distinguished by their individual characteristics of grain-size, sorting, texture, bedding, and sediment source. Sediment distribution patterns show a large turbidite fan complex extending across the northeastern portion of the basin. Recent turbidite deposition in the Weddell Sea has occurred under polar glacial conditions. This has produced sequences distinctly different from those occurring in temperate glacial environments, as in the northern high latitudes. Polar turbidites consist of massive, thick-bedded gravels, sands, silts, and muds, which are significantly depleted in silt. Temperate turbidites are rich in silt, and typically consist of interlaminated, graded, silts and muds. Similarities exist between Weddell Basin and Bellingshausen Basin seismic data. These data suggest that turbidite deposits constitute most of the sediment fill in these basins