Post-glacial flooding of the Beringia Land Bridge dated to 11,000 cal yrs BP based on new geophysical and sediment records

• Main Authors: Jakobsson, M., Pearce, C., Cronin, T. M., Backman, Jan, Anderson, L. G., Barrientos, Natalia, Björk, R.G., Coxall, Helen, de Boer, A, Mayer, L. A., Mörth, Carl-Magnus, Nilsson, J., Rattray, J. E., Stranne, C., Semilietov, I., O'Regan, Matt
• Format: Report
• Language: English
• Published: EGU 2017
• Subjects: Arctic; Arctic Ocean; Chukchi Sea; Bering Strait; Pacific; Chukchi; Foraminifera*; Beringia
• Online Access: https://pure.au.dk/portal/da/publications/postglacial-flooding-of-the-beringia-land-bridge-dated-to-11000-cal-yrs-bp-based-on-new-geophysical-and-sediment-records(b0138a00-d86f-4b07-9124-3db2c824443d).html; https://doi.org/10.5194/cp-2017-11

The Bering Strait connects the Arctic and Pacific oceans and separates the North American and Asian land masses. The presently shallow (textasciitilde 53 m) strait was exposed during the sea-level lowstand of the last glacial period, which permitted human migration across a land bridge referred to as Beringia. Proxy studies (stabile isotope composition of foraminifera, whale migration into the Arctic Ocean, mollusc and insect fossils and paleobotanical data) have suggested a range of ages for the Bering Strait reopening, mainly falling within the Younger Dryas stadial (12.9–11.7 ka). Here we provide new information on the deglacial and post-glacial evolution of the Arctic-Pacific connection through the Bering Strait based on analyses of geological and geophysical data from Herald Canyon, located north of the Bering Strait on the Chukchi Sea shelf region in the western Arctic Ocean. Our results suggest an initial opening at about 11 ka in the earliest Holocene, which is later when compared to several previous studies. Our key evidence is based on a well dated core from Herald Canyon, in which a shift from a near-shore environment to a Pacific-influenced open marine setting around 11 ka is observed. The shift corresponds to Meltwater Pulse 1b (MWP1b) and is interpreted to signify relatively rapid breaching of the Bering Strait and submergence of the large Beringia Land Bridge. Although precise rates of sea-level rise cannot be quantified, our new results suggest that the late deglacial sea-level rise was rapid, and occurred after the end of the Younger Dryas stadial.