Since Shpanberg Strait was opened by sea-level transgression about 12,000 B.P., one-third to one-half of the sediment load of the Yukon River has bypassed the northern Bering Sea to accumulate in the thick blanket of Holocene1 sediment in the southern Chukchi Sea. Prior to the transgression of Norton Sound about 9500 B.P., more than half of the Yukon River sediment may have been bypassed to the Chukchi Sea. After about 5000 B.P., deposition of Yukon sediment significantly increased in the Bering Sea when the present Yukon subdelta was apparently formed in the southern part of Norton Sound. Even now, one-third of the Yukon load may be carried to the Chukchi Sea, because the continual strong northward circulation of the Alaskan Coastal Water advects some of the Yukon sediment plume, along with masses of sediment intermittently resuspended by storms.

This major displacement of sediment 500 to 1,000 km from a river source has important implications for models of advective transport over shelves, paleogeographic reconstructions of sedimentary environments in epicontinental seas, and development of nonsubsiding deltas, such as the Yukon.

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