Multichannel seismic evidence bearing on the origin of Bowers Ridge, Bering Sea

GSA Bulletin
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Abstract

Bowers Ridge is a large, arcuate sub-marine ridge that extends north and west from the Aleutian Ridge and separates the abyssal Aleutian and Bowers Basins in the Bering Sea. Two multichannel seismic-reflection lines recorded in 1976 over Bowers Ridge and the adjacent basins confirm the existence of 8- to 10-km-thick sediment wedges on the north side of Bowers Ridge and at the base of the Bering continental margin. Deformed sediment within the Bowers wedge indicates that subduction of the adjacent ocean crust beneath the ridge probably occurred prior to middle Cenozoic time. Flat-lying reflectors near the bottom of the trench suggest that a bathymetric trough and large ridge existed in Mesozoic time. The major period of underthrusting, subsidence, and in-filling of the trench probably occurred from Mesozoic to early Tertiary time. Small amounts of underthrusting may have continued after the early Tertiary development of the Aleutian Ridge; however, by middle Miocene time, the formerly subaerial Bowers Ridge had subsided below sea level.

The multichannel seismic data do not show evidence for a buried spreading center within the eastern Aleutian Basin. Consequently, the sediment wedges (trenches) at both Bowers Ridge and the Bering continental margin are believed to be the consequence of subduction that occurred during the convergence of the ridge and the margin. The large size of Bowers Ridge suggests that a large amount of convergence has occurred since Mesozoic time. If Bowers Ridge was a large feature in Mesozoic time, as suggested by the apparent bathymetric trough, then the ridge may be as old or older than the Aleutian Ridge to which it connects.

Publication type Article
Publication Subtype Journal Article
Title Multichannel seismic evidence bearing on the origin of Bowers Ridge, Bering Sea
Series title GSA Bulletin
DOI 10.1130/0016-7606(1981)92<474:MSEBOT>2.0.CO;2
Volume 92
Issue 7
Year Published 1981
Language English
Publisher GSA
Contributing office(s) Pacific Coastal and Marine Science Center
Description 11 p.
First page 474
Last page 484
Other Geospatial Bowers Ridge, Bering Sea
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