Late pleistocene sedimentation history of the Shirshov Ridge, Bering Sea

Abstract

Abstract-The analysis of the lithology, grain size distribution, clay minerals, and geochemistry of Upper Pleistocene sediments from the submarine Shirshov Ridge (Bering Sea) showed that the main source area was the Yukon-Tanana terrane of Central Alaska. The sedimentary materials were transported by the Yukon River through Beringia up to the shelf break, where they were entrained by a strong northwestward flowing sea current. The lithological data revealed several pulses of ice rafted debris deposition, roughly synchronous with Heinrich events, and periods of weaker bottom current intensity. Based on the geochemical results, we distinguished intervals of an increase in paleoproductivity and extension of the oxygen minimum zone. The results suggest that there were three stages of deposition driven by glacioeustatic sea level fluctuations and glacial cycles in Alaska.

Deglacial Land-Ocean Linkages at the Alaskan Continental Margin in the Bering Sea

“…A common source for Yukonderived sediments and marine sediments along the Arctic coast of Alaska are kaolinite-bearing Mesozoic sedimentary rocks and paleosols as well as altered Paleozoic tuff beds, that prevail in northern Alaska and form part of the mountain chain of the Brooks Range (Naidu et al, 1971;Naidu and Mowatt, 1983;Dalrymple and Maass, 1987;Borden et al, 2010;Darby et al, 2011). Kaolinite in the course of the Yukon River may also originate from diagenetic clays in Cretaceous-Cenozoic coal deposits of the Yukon-Tanana River catchments of central Alaska (Triplehorn, 1976;Merritt, 1986;Levitan et al, 2013).…”