Articles | Volume 13, issue 8
Clim. Past, 13, 991–1005, 2017

Special issue: Climate–carbon–cryosphere interactions in the...

Clim. Past, 13, 991–1005, 2017

Research article 01 Aug 2017

Research article | 01 Aug 2017

Post-glacial flooding of the Bering Land Bridge dated to 11 cal ka BP based on new geophysical and sediment records

Martin Jakobsson1, Christof Pearce1,2, Thomas M. Cronin3, Jan Backman1, Leif G. Anderson4, Natalia Barrientos1, Göran Björk4, Helen Coxall1, Agatha de Boer1, Larry A. Mayer5, Carl-Magnus Mörth1, Johan Nilsson6, Jayne E. Rattray1, Christian Stranne1,5, Igor Semiletov7,8, and Matt O'Regan1 Martin Jakobsson et al.
  • 1Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, 10691 Stockholm, Sweden
  • 2Department of Geoscience, Aarhus University, 8000 Aarhus, Denmark
  • 3US Geological Survey MS926A, Reston, Virginia 20192, USA
  • 4Department of Marine Sciences, University of Gothenburg, 412 96 Gothenburg, Sweden
  • 5Center for Coastal and Ocean Mapping, University of New Hampshire, Durham, New Hampshire 03824, USA
  • 6Department of Meteorology, Stockholm University, 106 91 Stockholm, Sweden
  • 7Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences, 690041 Vladivostok, Russia
  • 8Tomsk Polytechnic University, Tomsk, Russia

Abstract. The Bering Strait connects the Arctic and Pacific oceans and separates the North American and Asian landmasses. The presently shallow ( ∼  53 m) strait was exposed during the sea level lowstand of the last glacial period, which permitted human migration across a land bridge today referred to as the Bering Land Bridge. Proxy studies (stable 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 cal ka BP). 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 cal ka BP in the earliest Holocene, which is later than in 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 at around 11 cal ka BP is observed. The shift corresponds to meltwater pulse 1b (MWP1b) and is interpreted to signify relatively rapid breaching of the Bering Strait and the submergence of the large Bering Land Bridge. Although the 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.

Short summary
The Arctic and Pacific oceans are connected by the presently ~53 m deep Bering Strait. During the last glacial period when the sea level was lower than today, the Bering Strait was exposed. Humans and animals could then migrate between Asia and North America across the formed land bridge. From analyses of sediment cores and geophysical mapping data from Herald Canyon north of the Bering Strait, we show that the land bridge was flooded about 11 000 years ago.