Speciation of trace elements for the prediction of isotope fractionation

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H02149
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Geochemistry/Cosmochemistry
• Research Institution: The University of Tokyo
• Principal Investigator: Takahashi Yoshio 東京大学, 大学院理学系研究科(理学部), 教授 (10304396)
• Co-Investigator(Kenkyū-buntansha): 大野 剛 学習院大学, 理学部, 准教授 (40452007) ; 飯塚 毅 東京大学, 大学院理学系研究科(理学部), 准教授 (70614569) ; 柏原 輝彦 国立研究開発法人海洋研究開発機構, 海底資源研究開発センター, 研究員 (70611515) ; 小暮 敏博 東京大学, 大学院理学系研究科(理学部), 教授 (50282728) ; 遠藤 一佳 東京大学, 大学院理学系研究科(理学部), 教授 (80251411)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 化学種解明 / 同位体分別 / モリブデン / 吸着構造 / XAFS

Outline of Final Research Achievements

Isotope fractionation of various elements in various geochemical systems has been predicted by the speciation of these elements in the samples, which can provide new isotopic geochemical tool to clarify the history of the earth and planet. For example, tungsten isotope fractionation between its dissolved species and adsorbed species on iron and manganese oxides has been studied based on the speciation and isotope analyses. The 0.6 permil isotope fractionation observed in this system can be useful for the better understanding of redox history of the earth, especially when applied with molybdenum isotope which is sensitive only for the adsorption on manganese oxide. Similar isotope fractionation was predicted and actually observed for germanium and rubidium in the adsorption systems. Moreover, isotope fractionation of Fe at the 4 permil level was observed during the evaporation of Fe such as in anthropogenic combustion process, which can be useful to distinguish source of Fe in aerosols.

Free Research Field

地球化学、環境化学