Channel geometry in the Riiser Larsen Sea
Sedimentologic investigations in Antarctica focus on a channel-levee system in the Riiser Larsen Sea. The levees carry thick sediments that reveal an adequate high resolution that make them suitable for paleoenvironment investigations. Although we still have no age datings, it is suggested that the core shown here covers the time until MIS 7.
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This part of Antarctica shows extreme differences in ice coverage during winter and summer
Goals of this part of the investigations include
- To relate paleocurrent-speed reconstructions to the paleoclimate development
- Paleoceanography and Paleoclimate reconstructions of this part of Antarctica
A long sediment core recovered from a levee top reveals carbonate-rich sediments with few IRD during the interglacials and carbonate-depleted sediments during the glacials in the sand fraction. High resolution granulometric data suggest that the channels are more active during interglacials than during glacials. Preliminary conclusions can be drawn: druing glacial climates surface water production in the RLS was low. Presumably a quasi-permanent ice cover prevailed that also prevented the deposition of IRD. During interglacials conditions were like those of today with a very large sea-ice cover in winter and open conditions in the austral summer. It can be assumed that dense water formation on the shelf is reduced during the glacials and somewhat higher during interglacials. Further investigations will show whether dense shelf waters, turbidity currents, or probably brines are principally responsible for the formation of channels and levees in the RLS.
