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

Abstract

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.

Sediment Provenance Changes in the Western Arctic Ocean in Response to Ice Rafting, Sea Level, and Oceanic Circulation Variations Since the Last Deglaciation

“…We thus hypothesize that the dolomite-rich IRD1A in core 05JPC could be dated at 11 ka cal BP similar to IRD1A from core 02PC ( Figure S1a). This IRD correlation would imply that the age for the opening of the Bering Strait may be older than 11 ka cal BP (Jakobsson et al, 2017) as previously suggested by Keigwin et al (2006), England and Furze (2008), and Elias et al (1992). Further investigations are required to gain a more precise chronology of the age constraint for the Bering Land Bridge flooding.…”

Rethinking long‐term vegetation dynamics: multiple glacial refugia and local expansion of a species complex

“…The abundance of Alnus in these pollen records does not display spatiotemporal patterns that would suggest the migration of Alnus across BLB. In these records, Alnus expanded markedly by 14 000 cal BP at several WB sites distant from BLB, but it did not do so until 10 000 cal BP at the WB sites near BLB and in Alaska, which was ~1000 yr after the flooding of BLB (Jakobsson et al ). Within Alaska, the earliest postglacial expansion of Alnus occurred in the northwestern Brooks Range, Kenai Peninsula and southeastern Alaska (Brubaker et al ), instead of in western coastal areas, as would be expected if WB had been the source area of postglacial Alnus expansion in Alaska.…”

Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea

“…12 and 11 ka (Elias et al, 1992;Keigwin et al, 2006;Jakobsson et al, 2017). The gradual intensification of the BSI inferred from the increase in chlorite content from ca.…”