Japan Geoscience Union Meeting 2019

Presentation information

[J] Oral

S (Solid Earth Sciences ) » S-GL Geology

[S-GL27] Geochronology and Isotope Geology

Thu. May 30, 2019 10:45 AM - 12:15 PM A10 (TOKYO BAY MAKUHARI HALL)

convener:Takahiro Tagami(Graduate School of Science, Kyoto University), Yuji Sano(Division of Ocean and Earth Systems, Atmosphere and Ocean Research Institute, University of Tokyo), Chairperson:Yuji Sano, Takahiro Tagami

11:15 AM - 11:30 AM

[SGL27-07] Estimation of Paleoenvironment by sedimentary rocks in Labrador, Cacada

*katsutaka sudo1, Yuji Sano1, Tsuyoshi Komiya1, Bakert David2, Michael Broadley2, Bernard Marty2 (1.University of Tokyo, 2.CRPG-CNRS, Université de Lorraine)

In the previous research, we reported isotopic compositions of graphite and carbonate in the 3.95Ga metasedimentary rocks from northern Labrador, Canada (Tashiro et al., 2017). Based on the isotopic shift of 20-30‰, we claimed a carbonate fixation by the Earth’s earliest life. In this work, we picked up graphite from the very old rocks collected in Labrador and Nuvvuagittuq, and measured volatile isotope compositions by the step-wise heating method. We analyzed nitrogen isotopes to investigate whether the organic carbon was producted by cyanobacteria or methanobacteria, and noble gas (argon, krypton, xenon) isotopes to determine the age of rocks. We have used two types of gas mass spectrometer; VG3600 for nitrogen, Helix-MC for noble gases. The obtained data together with experimental method will be given in the presentation.