The Cosmonaut Sea Wedge |
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| Authors: | K Solli B Kuvaas Y Kristoffersen G Leitchenkov J Guseva V Gandjukhin |
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| Institution: | (1) Department of Earth Science, University of Bergen, 5007 Bergen, Norway;(2) VNIIOkeangeologia, 1, Angliysky Ave., 190 121 St. Petersburg, Russia;(3) PMGRE, 24, Pobedy Street, 189510 Lomonosov, Russia |
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| Abstract: | A set of multi-channel seismic profiles (∼15,000 km) is used to study the depositional evolution of the Cosmonaut Sea margin
of East Antarctica. We recognize a regional sediment wedge, below the upper parts of the continental rise, herein termed the
Cosmonaut Sea Wedge. The wedge is situated stratigraphically below the inferred glaciomarine section and extends for at least
1,200 km along the continental margin with a width that ranges from 80 to about 250 km. The morphology of the wedge and its
associated depositional features indicate a complex depositional history, where the deep marine depositional sites were influenced
by both downslope and alongslope processes. This interaction resulted in the formation of several proximal depocentres, which
at their distal northern end are flanked by elongated mounded drifts and contourite sheets. The internal stratification of
the mounded drift deposits indicates that westward flowing bottom currents reworked the marginal deposits. The action of these
currents together with sea-level changes is considered to have controlled the growth of the wedge. We interpret the Cosmonaut
Sea Wedge as a composite feature comprising several bottom current reworked fan systems. The wide spectrum of depositional
geometries in the stratigraphic column reflects dramatic variations in sediment supply from the continental margin as well
as varying interaction between downslope and alongslope processes. |
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| Keywords: | Antarctica Cosmonaut Sea Deep-sea deposits Depositional processes Seismics |
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