A new contouring of the Aleutian abyssal plain at 25 m intervals defines it as a complex of coalescing fans built by four major channels and their distributaries. Toward their source these channels converge to the northeast to a point in line with Shelikof Strait, Cook Inlet and the Susitna River basin, which drains the Alaska Range. The Alaska Range is a likely source of sediments for the Aleutian plain. From an analysis of the evolution of the fan, it appears the channels have operated successively from west to east, as suggested by the thinning of the pelagic layer in that direction. Viewing these facts in light of the plate tectonic hypothesis, one can imagine that as the Pacific plate was moving northwesterly toward the Aleutian Trench, an extended Susitna River was spilling its load of sediments through successive channels. The most ancient Seamap channel is now slipping into the trench, while the easternmost one, Taurus, represents the most recent road followed by sediments into the deep sea before the final interruption of the turbidite supply.

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