The northern Bering Sea is a large epicontinental shelf area of less than 50 m depth that is dominated by a mean northward current toward Bering Strait. Bathymetric

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constrictions increase flow speeds to about 50 to 200 cm/sec causing the strongest currents on the eastern side of the straits. Geoprobe and current mooring stations show that tidal flows and storm-driven currents, including storm surge runoff, can significantly increase bottom current speeds in certain areas.

Topographic expression of the strong current regime occurs as ridges and swales in straits and scour depressions on shoal flanks. Large leeside shoals as much as 100 km long are constructed on the north side of islands and westward-projecting landmasses. These presently developing sand bodies are supplied with sand eroded from upcurrent beach and delta deposits. Strong currents presently remold the crests of the leeside and other relict offshore sand ridges into a complex series of small- and large-scale mobile bed-form fields.

Strong northward flow influences sediment composition and facies distribution over much of the region as well as the patterns of storm sand layers, ice scour marks, and large (25 to 150 m) scour depressions in modern sandy silt. The modern sedimentary facies on the western Yukon delta have been truncated by strong currents in eastern Shpanberg Strait. A substantial part of Yukon Holocene sediment has been displaced from Norton Sound by storm surge currents and the mean northward flow, bypassing Chirikov Basin, to be deposited 1,000 km to the north in Chukchi Sea. The increasing current speeds toward Bering Strait also control the offshore gradation of Holocene transgressive sand facies. The gradation to stronger currents in eastern strait areas results in coarser grain size and also i creased concentrations of shell fragments and heavy minerals.

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