Stratigraphic constraints on late Pleistocene glacial erosion and deglaciation of the Chukchi margin, Arctic Ocean

Abstract At least two episodes of glacial erosion of the Chukchi margin at water depths to ∼ 450 m and 750 m have been indicated by geophysical seafloor data. We examine sediment stratigraphy in these areas to verify the inferred erosion and to understand its nature and timing. Our data within the e...

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Bibliographic Details
Published in:Quaternary Research
Main Authors: Polyak, Leonid, Darby, Dennis A., Bischof, Jens F., Jakobsson, Martin
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 2007
Subjects:
Arctic
Arctic Ocean
Bering Strait
Amerasia Basin
Chukchi
Foraminifera*
Ice Sheet
Ice Shelves
Iceberg*
Sea ice
Online Access:http://dx.doi.org/10.1016/j.yqres.2006.08.001
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Summary:Abstract At least two episodes of glacial erosion of the Chukchi margin at water depths to ∼ 450 m and 750 m have been indicated by geophysical seafloor data. We examine sediment stratigraphy in these areas to verify the inferred erosion and to understand its nature and timing. Our data within the eroded areas show the presence of glaciogenic diamictons composed mostly of reworked local bedrock. The diamictons are estimated to form during the last glacial maximum (LGM) and an earlier glacial event, possibly between OIS 4 to 5d. Both erosional events were presumably caused by the grounding of ice shelves originating from the Laurentide ice sheet. Broader glaciological settings differed between these events as indicated by different orientations of flutes on eroded seafloor. Postglacial sedimentation evolved from iceberg-dominated environments to those controlled by sea-ice rafting and marine processes in the Holocene. A prominent minimum in planktonic foraminiferal δ 18 O is identified in deglacial sediments at an estimated age near 13,000 cal yr BP. This δ 18 O minimum, also reported elsewhere in the Amerasia Basin, is probably related to a major Laurentide meltwater pulse at the Younger Dryas onset. The Bering Strait opening is also marked in the composition of late deglacial Chukchi sediments.

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