Analyses of environmental change in the continental area and marginal sea of the Arctic using radiogenic and stable isotopes of trace metal elements

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In this project, trace metal isotopes such as radiogenic Sr and Nd isotopes and stable Fe isotope were analyzed to examine the inflow and transportation of terrigenous material into the marginal seas such as the Bering and Okhotsk Seas. Isotope analyses of the Fe-Mn oxyhydroxides and carbonate in the Bering Sea sediments show that seawater Sr and Nd isotopes vary depending on weathering of the surrounding continental crusts such as Yukon River basin and the island-arc volcanic rocks such as Aleutians. In addition, iron of Fe-Mn oxyhydroxides and carbonate in the Okhotsk Sea has a "light" isotope composition, which suggests the supply from the Amur River. The regional and temporal variations of the Sr and Nd isotopes of the surface detrital sediments in the Bering and Chukchi Seas over the past 100 years reveal correlation of the terrigenous material supply from the surrounding continents and the annual mean SAT (surface air temperature) for the Arctic.