A “Marine”; ice cap in South Beringia (a working hypothesis)

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Abstract
During glacio‐eustatic lowering of sea level, the shallow northeastern portion of the Bering Sea became a part of the Bering Land Bridge while the sea's deep southwestern portion remained part of the ocean. Judging by indirect evidence, the deep portion was glaciated. Our analysis stresses a multifacetted analogy between the Bering Sea and the Norwegian‐Greenland Sea which strongly suggests that the conditions conducive to ice‐sheet growth existed over both seas. The intensified polar front in the “glacial”; North Pacific, like that in the “glacial”; North Atlantic, acted as a barrier to northward flow of subtropical water; also branches of the Kuroshio Current ceased to enter the Bering Sea. This resulted in a negative heat balance in the sea, which must have forced the inception of a marine ice sheet through an ice‐shelf mechanism. The South‐Beringian Ice Sheet is visualized as a single dynamic system of marine and terrestrial glaciers with a total area of 2.6–2.7 million km2; its central portion was the Bering Ice Shelf constrained north of the Aleutian‐Commander Ridge and resting on the Shirshov and Bowers ridges. The large submarine canyons of southern Beringia, the flattened tops of the above ridges, and “submerged”; terraces on the continental slopes were connected with glacial scouring, while the system of coalescing turbidite fans at depth are considered to be glaciomarine. In reconstructions of sea‐surface summer temperatures for the North Pacific 18,000 years ago, the 0° isotherm should be plotted south of the Aleutian‐Commander Ridge and a separate zone of steep thermal gradient is interpolated immediately south of that isotherm.