Clay mineral dispersal patterns in the north Bering and Chukchi Seas

Abstract

Characterization of the clay mineralogic constituents of the <2 μm e.s.d. (equivalent spherical diameter) size fraction of contemporary marine and fluvial sediments from the north Bering Sea—Chukchi Sea region and adjacent land areas has resulted in delineation of suites dominated by broadly defined “illitic” and “expandable group” components, with lesser amounts of chlorite and kaolinite. Distribution patterns elucidated indicate net northward transport of sediments relatively enriched in the “expandable group” with predominant terrigen ous source from the Yukon River system. This material is distributed across the study area in a medial zone along a general north—south trend, with peripherally decreasing relative amounts of this “expandable group” component, and concomitant relative increases in the “illitic” components. These patterns are consistent with known physical oceanographic and regional geologic relationships, in terms of sediment sources, transport processes, and depositional mechanisms. The foregoing suggest, further, that consideration of the stratigraphic relationships of these clay mineral component-types, as a function of time, in relevant marine sediments north and south of the present Bering Strait, should be informative with respect to regional Quaternary paleogeography, as related to global sea level fluctuations during glacial and interglacial episodes.