The de Long Trough:A newly discovered glacial trough on the East Siberian continental margin

Ice sheets extending over parts of the East Siberian continental shelf have been proposed for the last glacial period and during the larger Pleistocene glaciations. The sparse data available over this sector of the Arctic Ocean have left the timing, extent and even existence of these ice sheets larg...

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Bibliographic Details
Published in:Climate of the Past
Main Authors: O'Regan, Matt, Backman, Jan, Barrientos, Natalia, Cronin, Thomas M., Gemery, Laura, Kirchner, Nina, Mayer, Larry A., Nilsson, Johan, Noormets, Riko, Pearce, Christof, Semiletov, Igor, Stranne, Christian, Jakobsson, Martin
Format: Article in Journal/Newspaper
Language:English
Published: 2017
Subjects:
Arctic
Arctic Ocean
De Long Islands
East Siberian Shelf
Long Islands
SWERUS-C3
Online Access:https://pure.au.dk/portal/da/publications/the-de-long-trough(34b91d90-1a7a-405e-b344-503275d020a8).html
https://doi.org/10.5194/cp-13-1269-2017
https://pure.au.dk/ws/files/117768919/cp_13_1269_2017.pdf
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Summary:Ice sheets extending over parts of the East Siberian continental shelf have been proposed for the last glacial period and during the larger Pleistocene glaciations. The sparse data available over this sector of the Arctic Ocean have left the timing, extent and even existence of these ice sheets largely unresolved. Here we present new geophysical mapping and sediment coring data from the East Siberian shelf and slope collected during the 2014 SWERUS-C3 expedition (SWERUS-C3: Swedish-Russian-US Arctic Ocean Investigation of Climate-Cryosphere-Carbon Interactions). The multibeam bathymetry and chirp sub-bottom profiles reveal a set of glacial landforms that include grounding zone formations along the outer continental shelf, seaward of which lies a > 65-m thick sequence of glacio-genic debris flows. The glacial landforms are interpreted to lie at the seaward end of a glacial trough-the first to be reported on the East Siberian margin, here referred to as the De Long Trough because of its location due north of the De Long Islands. Stratigraphy and dating of sediment cores show that a drape of acoustically laminated sediments covering the glacial deposits is older than 50 kyr BP. This provides direct evidence for extensive glacial activity on the Siberian shelf that predates the Last Glacial Maximum and most likely occurred during the Saalian (Marine Isotope Stage (MIS) 6).

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