JpGU-AGU Joint Meeting 2020

Presentation information

[E] Poster

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS11] Expedition Earth: discovering our planet's past and future through scientific drilling

convener:Junichiro Kuroda(Department of Ocean Floor Geoscience, Atmosphere and Ocean Research Institute, the University of Tokyo), Katsuyoshi Michibayashi(Department of Earth and Planetary Sciences, Nagoya University), Kohtaro Ujiie(Graduate School of Life and Environmental Sciences, University of Tsukuba), Clive Robert Neal(University of Notre Dame)

[MIS11-P07] Analytical method of noble gases using cuttings to understand distribution and origin of noble gases in accretionary prism in precise -

*Tomohiro Toki1, Shugo Kurahashi1, Naoto Takahata2, Yuji Sano2,3 (1.Faculty of Science, University of the Ryukyus, 2.Atmosphere and Ocean Research Institute, The University of Tokyo, 3.Institute of Surface-Earth System Science, Tianjin University)

Keywords:cuttings, noble gas, analytical method, accretionary prism

In this study, we measured noble gases from cuttings crushed in a vacuum, and obtained a data set of noble gases free from air contamination. As a result, the contribution rate of air-saturated interstitial water could be determined, and the helium isotope ratio released from the slab of the Philippine Sea Plate could be determined accurately. In addition, mantle-derived helium laterally would be supplied from wedge mantle around 1503 mbsf. Based on the lithology and hydrocarbons distribution, the sandstone layer distributed between 1000 and 1500 mbsf could play a role as flow path of deep-rooted gas from great depths. To obtain more accurate in-situ information than gas analysis using mud gas, we propose gas analysis using cuttings as an international standard for exploration of noble gas distribution during drilling.