Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 13, 1269-1284, 2017
https://doi.org/10.5194/cp-13-1269-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
28 Sep 2017
The De Long Trough: a newly discovered glacial trough on the East Siberian continental margin
Matt O'Regan1,2, Jan Backman1,2, Natalia Barrientos1,2, Thomas M. Cronin3, Laura Gemery3, Nina Kirchner2,4, Larry A. Mayer5, Johan Nilsson2,6, Riko Noormets7, Christof Pearce1,2,8, Igor Semiletov9,10, Christian Stranne1,2,5, and Martin Jakobsson1,2 1Department of Geological Sciences, Stockholm University, 10691, Stockholm, Sweden
2Bolin Centre for Climate Research, Stockholm University, 10691, Stockholm, Sweden
3US Geological Survey MS926A, Reston, Virginia 20192, USA
4Department of Physical Geography (NG), Stockholm University, 10691, Stockholm, Sweden
5Center for Coastal and Ocean Mapping, University of New Hampshire, Durham, New Hampshire 03824, USA
6Department of Meteorology, Stockholm University, 10691, Stockholm, Sweden
7University Centre in Svalbard (UNIS), P.O. Box 156, 9171, Longyearbyen, Svalbard, Norway
8Department of Geoscience, Aarhus University, 8000, Aarhus, Denmark
9Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences, 690041, Vladivostok, Russia
10Tomsk National Research Polytechnic University, 634050, Tomsk, Russia
Abstract. 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 cal 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).

Citation: O'Regan, M., Backman, J., Barrientos, N., Cronin, T. M., Gemery, L., Kirchner, N., Mayer, L. A., Nilsson, J., Noormets, R., Pearce, C., Semiletov, I., Stranne, C., and Jakobsson, M.: The De Long Trough: a newly discovered glacial trough on the East Siberian continental margin, Clim. Past, 13, 1269-1284, https://doi.org/10.5194/cp-13-1269-2017, 2017.
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Short summary
Past glacial activity on the East Siberian continental margin is poorly known, partly due to the lack of geomorphological evidence. Here we present geophysical mapping and sediment coring data from the East Siberian shelf and slope revealing the presence of a glacially excavated cross-shelf trough reaching to the continental shelf edge north of the De Long Islands. The data provide direct evidence for extensive glacial activity on the Siberian shelf that predates the Last Glacial Maximum.
Past glacial activity on the East Siberian continental margin is poorly known, partly due to the...
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