JpGU-AGU Joint Meeting 2017

Presentation information

[EJ] Poster

S (Solid Earth Sciences) » S-CG Complex & General

[S-CG71] [EJ] Ocean Floor Geoscience

Wed. May 24, 2017 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL7)

[SCG71-P02] Chemical and isotopic compositions of interstitial water from the Izena hydrothermal field

*Tomohiro Toki1, Tsubasa Otake2, Jun-ichiro Ishibashi3, Yohei Matsui4, Hirokazu Kato3, Shigeshi Fuchida5, Rena Miyahara3, Akihi Tsutsumi3, Shunsuke Nakamura2, Ryuhei Kawakida2, Hirotaka Uza1, Riki Uehara1, Ryuichi Shinjo1, Tatsuo Nozaki4, Hidenori Kumagai4, Lena Maeda4, CK16-05 on-board member (1.University of the Ryukyus, 2.Hokkaido University, 3.Kyushu University, 4.JAMSTEC, 5.NIES)

Keywords:Izena Hole, hydrothermal system, interstitial water, chemical and isotopic compositions

In the previous SIP cruises, several hydrothermal sites have been drilled in the Iheya North Knoll, and distribution of sulfide ore deposits and hydrothermal fluids have been unraveled. However, the sulfide ore deposits in the Iheya North Knoll are relatively small to understand detailed formation processes of a massive hydrothermal ore deposits, particularly factors controlling the scale and grade of the deposits, which will be useful for exploration of large and high-grade deposits. In the Izena Hole, two hydrothermal active fields have been reported, and they have been called Hakurei and JADE sites (Halbach et al. 1989). At Hakurei site, several mounds up to tens of meters in height lie in lines. A potential sulfide ore body has been also pointed out beneath the mound of sulfide by JOGMEC ( In this study, coring was conducted around the massive hydrothermal ore deposits at Hakurei site, and chemical compositions of interstitial water and headspace gases from sediments or volcanic rocks were investigated. The purposes of this study are (1) to investigate the influence of hydrothermal activities on the chemistry of interstitial water and headspace gas and (2) to understand how the distribution of hydrothermal fluids below the seafloor is related to the growth of massive hydrothermal ore deposits.