Structure of the Berings Sea and the Aleutian Ridge

Abstract

Seismic refraction profiles made in the Bering Sea in three geologic provinces — the Aleutian ridge, the Aleutian basin, and the eastern shelf — show that the Aleutian basin has a structure that can be interpreted as an area with oceanic structure on top of which has been deposited 4 km of sediment and volcanic rocks; the mantle is at a depth of 14 km, 3 km deeper than normal, and the ocean floor 1.3 km shallower than normal. Beneath the Aleutian ridge and the eastern shelf, the mantle depth is 22 km or more. The Aleutian ridge has acted as a sediment barrier, and sediments from the coasts of Alaska and Siberia have been trapped behind it; eventually the Aleutian basin should fill to the brim and form an addition to the continental mass.