Geochemistry of the marine sediments

Abstract

A goal of this study is to obtain a clear and systematic description of the sediment which may give a clue of the accumulation history and the paleoproductivity in the ocean. In this study, I have obtained a sediment cores from the northern North Pacific Ocean (station 3) and the Bering Sea (station 4) in order to elucidate the record of the past and present. The sediment cores, which differed in redox conditions, have been studied by measuring several chemical elements (Ba, opal, U, Cd, Mn, Ti and Al), radionuclides (- ^-Th, 230rh) as well as the contents of carbonate and organic carbon. Both cores consists of diatomaceous ooze, with a core at station 4 containing a fairly large amount of biogenic opal although it is dominated with fine-grained terrigenous material.