Sedimentary proxies for Pacific water inflow through the Herald Canyon, western Arctic Ocean
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ORIGINAL ARTICLE
Sedimentary proxies for Pacific water inflow through the Herald Canyon, western Arctic Ocean Henrik Swärd1,2 · Matt O’Regan1,2 · Christof Pearce3 · Igor Semiletov4,5 · Christian Stranne1,2 · Henrik Tarras1 · Martin Jakobsson1,2 Received: 20 November 2017 / Accepted: 12 June 2018 © The Author(s) 2018
Abstract Pacific water inflow to the Arctic Ocean occurs through the shallow Bering Strait. With a present sill depth of only 53 m, this gateway has been frequently closed during glacial sea-level low stands of the Pleistocene. Here, we investigate the sedimentological and mineralogical response to sea-level rise and the opening of the Bering Strait during the last deglaciation in a 6.1 m-long marine sediment core (SWERUS-L2-4-PC1) from the Herald Canyon. Grain size data indicate an abrupt erosional contact at 412 cm down core that likely formed when Pacific waters first started to flow into the Arctic Ocean around 11 cal ka BP, and was topographically steered into the Herald Canyon. A transitional unit between 412 and 390 cm appears to be a condensed interval with minimal local sedimentation. The underlying sediments, deposited in a shallow, river-proximal setting, exhibit a rather uniform bulk and clay mineral composition similar to mineral assemblages from surface sediment samples of the Chukchi Sea. Enhanced contributions from Pacific waters above 390 cm (
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