Input of Glaciomarine Sediments along the East Antarctic Continental Margin; Depositional Processes on the Cosmonaut Sea Continental Slope and Rise and a Regional Acoustic Stratigraphic Correlation from 40° W to 80° E |
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| Authors: | B Kuvaas Y Kristoffersen J Guseva G Leitchenkov V Gandjukhin G Kudryavtsev |
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| Institution: | (1) Department of Earth Science, University of Bergen, Allegaten 41, 5007 Bergen, Norway;(2) PMGRE, 24 Pobedy Street, 189510 Lomonosov, Russia;(3) VNIIOkeangeologia, 1 Angliysky Avenue, 190 121 St. Petersburg, Russia |
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| Abstract: | Multichannel seismic reflection data from the Cosmonaut Sea margin of East Antarctica have been interpreted in terms of depositional
processes in the continental slope and rise area. A major sediment lens is present below the upper continental rise along
the entire Cosmonaut Sea margin. The lens probably consists of sediments supplied from the shelf and slope, being constantly
reworked by westward flowing bottom currents, which redeposited the sediments into a large scale drift deposit prior to the
main glaciogenic input along the margin. High-relief semicircular or elongated depositional structures are also found on the
upper continental rise stratigraphically above the regional sediment lens, and were deposited by the combined influence of
downslope and alongslope sediment transport. On the lower continental rise, large-scale sediment bodies extend perpendicular
to the continental margin and were deposited as a result of downslope turbidity transport and westward flowing bottom currents
after initiation of glacigenic input to the slope and rise. We compare the seismostratigraphic signatures along the continental
margin segments of the adjacent Riiser Larsen Sea, the Weddell Sea and the Prydz Bay/Cooperation Sea, focussing on indications
that may be interpreted as a preglacial-glaciomarine transition in the depositional environment. We suggest that earliest
glaciogenic input to the continental slope and rise occurred in the Prydz Bay and possibly in the Weddell Sea. At a later
stage, an intensification of the oceanic circulation pattern occurred, resulting in the deposition of the regional plastered
drift deposit along the Cosmonaut Sea margin, as well as the initiation of large drift deposits in the Cooperation Sea. At
an even later stage, possibly in the middle Miocene, glacial advances across the continental shelf were initiated along the
Cosmonaut Sea and the Riiser Larsen Sea continental margins. |
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| Keywords: | Antarctica bottom currents contourites Cosmonaut Sea glacial advances glaciomarine sediments Prydz Bay Riiser Larsen Sea turbidites Weddell Sea |
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