日本地球惑星科学連合2018年大会

講演情報

[JJ] ポスター発表

セッション記号 H (地球人間圏科学) » H-TT 計測技術・研究手法

[H-TT18] 環境トレーサビリティー手法の開発と適用

2018年5月22日(火) 15:30 〜 17:00 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:陀安 一郎(総合地球環境学研究所)、中野 孝教(大学共同利用機関法人 人間文化研究機構 総合地球環境学研究所)、木庭 啓介(京都大学生態学研究センター)

[HTT18-P09] Geochemical characteristics of hydrothermal fluids observed along Median Tectonic Line in Mie-Prefecture, Japan.

*Umam Rofiqul1谷水 雅治1杉本 直人1仲井 涼1森 康則2 (1.Kwansei Gakuin University、2.Mie Prefecture Health and Environmental Research Institute, Japan)

キーワード:Groundwater、Geofluid、Median Tectonic Line、Mass spectrometry、Hot spring

Island arc magmatism is considered to be triggered by the addition of fluids dehydrated from subducting slab. The relationship among volcanism, hydrothermal ore forming, and hot spring in island arc is therefore important to understand distribution of geofluid in the area. We investigated hot spring in Mie-prefecture to estimate their origin. Various types of hot spring are observed in that area, and their origin and characteristics are estimated from dissolved trace element concentrations and their isotope systematics.

We investigated the ratios of 11B/10B and 7Li/6Li of hot spring water samples as well as 18O/16O and D/H isotope ratios of water. Resultant 18O/16O-D/H ratios of water were mainly plotted along the fractionation trend of meteoric water and a mixing trend with seawater, but some samples have isotopic shifts toward heavy 18O/16O ratios, which indicate interactions with rocks under high temperature. Their 11B/10B and 7Li/6Li ratios showed very low values for some samples, which suggest that the fluids are originated from deeper part of the earth crust. In addition, a decoupling between the two isotope systems is observed.