日本地球惑星科学連合2019年大会

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[J] 口頭発表

セッション記号 S (固体地球科学) » S-GL 地質学

[S-GL27] 地球年代学・同位体地球科学

2019年5月30日(木) 10:45 〜 12:15 A10 (東京ベイ幕張ホール)

コンビーナ:田上 高広(京都大学大学院理学研究科)、佐野 有司(東京大学大気海洋研究所海洋地球システム研究系)、座長:佐野 有司田上 高広

10:45 〜 11:15

[SGL27-06] Geochemical origin/cycle analysis with isotopologues and isotopomers

★Invited Papers

*吉田 尚弘1 (1.東京工業大学物質理工学院, 地球生命研究所)

キーワード:アイソトポマー、アイソトポログ、地球化学的循環、軽元素安定同位体

Since the 1950’s, the stable isotope composition of natural samples has proved to be a unique tool for the study of geological and biological processes, their evolution and effect on Earth’s surface environment. However, due to technical and conceptual limitations, the complete set of information potentially contained in the different modes of isotopic substitution remains largely unexplored. In this study, using new methodological developments that allow analysis of more isotopically substituted molecules, we are developing new tracers in 3 modes of isotopic substitution, fully integrated in the study of geological, biological and anthropogenic processes which affect the origin and evolution of the Earth’s surface environment.

3 modes of substitution of stable isotopes in a single molecular species are;

1) Position specific isotope abundance (PSIA): Our group has pioneered PSIA of N2O1,2) and organic molecules using classic isotope mass spectrometry3) and nuclear magnetic resonance4,5). We have shown that PSIA of hydrocarbons and organic acids allows to distinguish between biological and non-biological processes4,6).

2) Mass-independent fractionation (MIF): The discovery of MIF of sulfur and oxygen in terrestrial samples has revolutionized environmental geochemistry and our understanding of the evolutionary history of the Earth's environment and life7-9).

3) Clumped isotopes (i.e. isotopologues and isotopomers with 2 minor isotopes) provide unique information about the temperature history of molecules such as carbonates10) or organic compounds11-13).

We are currently developing new and improved tracers of environmental and biogeochemical processes and applying them to the environmental diagnosis. We are establishing and standardizing new methods for the analyses of every 3 complex modes of isotopic substitution, and unifying them to develop ultimate environmental diagnosis.

The development and application of these new isotopic tools to the environment evolution, in modern and more ancient eras, represents an important conceptual advance in Earth and life sciences. This will open new areas of research about, for example, the geological production of some atmospheric gases, metabolic processes and the biological fixation of atmospheric CO2, the production and cycling of pollutant gas by industrial processes. As a whole, these new tracers will be integrated together for diagnosis of the Earth’s environment.

References:

1)Yoshida & Toyoda, 2000 Nature; 2)Yamazaki, Toyoda, Yoshida, et al., 2014 Biogeosciences; 3)Yamada, Yoshida, et al., 2002 RCM; 4)Gilbert, Yamada, Yoshida, 2013 Anal. Chem., and 5) 2014 Anal. Chim. Acta; 6)Gilbert, Yamada, Ueno, Yoshida 2016 Geochim. Cosmochim. Acta; 7)Danielache, Ueno, Yoshida et al., 2008 J. Geophys. Res.; 8)Hattori, Danielache, Ueno, Yoshida et al., 2013 PNAS, 9)Ueno, 2015 Science; 10) Yoshida, Abe, Yamada et al., RCM, 2013; 11)Tsuji, Yamada, Yoshida et al., 2012 Sensor;: 12)Ono et al., 2014 Anal. Chem.; 13)Stolper et al., 2014 Science.