[M-GI33] データ駆動地球惑星科学

[MGI33-04] 沖縄トラフ海底熱水鉱床の全岩化学組成データに対する独立成分分析の適用

*愛知 昭人¹、安川 和孝^1,2、野崎 達生^3,1,4,2、高谷 雄太郎^5,3,2、石田 美月¹、田中 えりか¹、中村 謙太郎¹、加藤 泰浩^1,2 (1.東京大学大学院工学系研究科、2.千葉工業大学次世代海洋資源研究センター、3.海洋研究開発機構、4.神戸大学、5.早稲田大学)

キーワード：熱水鉱床、沖縄トラフ、熱水鉱化作用、多変量解析、独立成分分析

Submarine hydrothermal activity is one of the key processes controlling the transfer of energy and materials from the Earth’s interior to surface systems including hydrosphere and biosphere. It is also an important process that produces mineral deposits of economic interest. In recent years, multiple scientific drilling cruises were conducted in the Okinawa Trough, a back-arc basin with a number of active hydrothermal vents [1-3], using the drilling vessel CHIKYU. The core samples contain various altered/unaltered volcaniclastic and hemipelagic sediments, as well as sulfide minerals. By ICP-QMS analysis, a comprehensive dataset of bulk chemical composition (>1,300 samples x 47 element contents) of the drilling core samples has been constructed.

In this study, we statistically analyzed the huge dataset using independent component analysis (ICA). ICA is a powerful method to recover mutually independent signals from an observed mixture of the source signals and it has been successfully applied to geochemical data [4-6]. We implemented ICA to identify multi-elemental features and their distributions involving geochemical heterogeneities in the (sub)seafloor hydrothermal deposits. In the presentation, through consideration of information of the extracted components, we will discuss the geochemical characteristics of the hydrothermal activities in the study area.


[1] Glasby et al. (2003) Ore. Geol. Rev. 23, 299-339.
[2] Nakajima et al. (2015) PLoS One. 10, e0123095.
[3] Nozaki et al. (2016) Sci. Rep. 6, 22163.
[4] Iwamori & Albarède (2008) Geochem. Geophys. Geosyst. 9, Q04033.
[5] Yasukawa et al. (2016) Sci. Rep. 6, 29603.
[6] Yasukawa et al. (2019) Geochem. Geophys. Geosyst. 20, 3402-3430.