Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/cp-2017-56
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
20 Apr 2017
Review status
This discussion paper is under review for the journal Climate of the Past (CP).
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, Gemery Laura3, Nina Kirchner2,4, Larry A. Mayer5, Johan Nilsson2,6, Riko Noormets7, Christof Pearce1,2,8, Igor Semilietov9,10, Christian Stranne1,2,5, and Martin Jakobsson1,2 1Department of Geological Sciences, Stockholm University, Stockholm, 106 91, Sweden
2Bolin Centre for Climate Research, Stockholm University, Stockholm, Sweden
3US Geological Survey MS926A, Reston, Virginia, 20192, USA
4Department of Physical Geography (NG), Stockholm University, SE-106 91 Stockholm, Sweden
5Center for Coastal and Ocean Mapping, University of New Hampshire, New Hampshire 03824, USA
6Department of Meteorology, Stockholm University, Stockholm, 106 91, Sweden
7University Centre in Svalbard (UNIS), P O Box 156, N-9171 Longyearbyen, Svalbard
8Department of Geoscience, Aarhus University, Aarhus, 8000, Denmark
9Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences, 690041 Vladivostok, Russia
10Tomsk National Research Polytechnic University, Tomsk, Russia
Abstract. Ice sheets extending over parts of the East Siberian continental shelf have been proposed during the last glacial period, and during the larger Pleistocene glaciations. The sparse data available over this sector of the Arctic Ocean has 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 glaciogenic 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 pre-dates 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., Laura, G., Kirchner, N., Mayer, L. A., Nilsson, J., Noormets, R., Pearce, C., Semilietov, I., Stranne, C., and Jakobsson, M.: De Long Trough: A newly discovered glacial trough on the East Siberian Continental Margin, Clim. Past Discuss., https://doi.org/10.5194/cp-2017-56, in review, 2017.
Matt O'Regan et al.
Matt O'Regan et al.
Matt O'Regan et al.

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Short summary
The existence of past ice sheets on the East Siberian continental margin is poorly known. In this paper, we present new geophysical mapping and sediment coring data from the East Siberian shelf and slope revealing the presence of a glacially excavated cross-shelf trough extending to the edge of the continental shelf north of the De Long Islands. The data provide direct evidence for extensive glacial activity on the Siberian shelf that pre-dates the Last Glacial Maximum.
The existence of past ice sheets on the East Siberian continental margin is poorly known. In...
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