Geodynamic Nature of the Trough-Shaped Sedimentary Depression in the Northern Aleutian Basin of the Bering Sea

摘要

Large marginal seas in the northwestern Pacific Ocean are characterized by a complex tectonic structure consisting of abyssal basins and uplifts of different ages and geodynamic origins, which reflect the long development history of its active margin. Interpretation of the tectonic nature of deep-sea isolated sedimentary basins is of importance for reconstructing their geodynamics. The Bering Sea, which was formed during the Cenozoic, is a typical example of such marginal basins. It comprises three deep-sea basins (Aleutian, Komandor, and Bowers) separated by the aseis-mic Shirshov and Bowers ridges and the Bering continental shelf that connects the Asian and North American continents. Seismic investigations revealed a depression in the basement of the northern Aleutian abyssal plain, which is filled with sediments over 9 km thick (North Aleutian sedimentary basin) [I]. This basin approximately 650 km long and 100 km wide extends from the foot of the Shirshov Ridge in the west to the base of the continental slope of the Bering shelf in the east. The purpose of this work is reconstruction of the geodynamic formation settings of the basin using available geological information and calculating anomalies of the D function (nonlinear coefficient of correlation between gravitational and magnetic fields) along profiles crossing the sedimentary basin in question.