JavaScript requeired.
Geochemical Journal
Geochemical Journal An open access journal for geochemistry
Published for geochemistry community from Geochemical Society of Japan.

Discovery of a new hydrothermal venting site in the southernmost Mariana Arc: Al-rich hydrothermal plumes and white smoker activity associated with biogenic methane

Toshitaka Gamo, Harue Masuda, Toshiro Yamanaka, Kei Okamura, Junichiro Ishibashi, Eiichiro Nakayama, Hajime Obata, Kiminori Shitashima, Yoshiro Nishio, Hiroshi Hasumoto, Masaharu Watanabe, Kyohiko Mitsuzawa, Nobukazu Seama, Urumu Tsunogai, Fumitaka Kouzuma, Yuji Sano
Geochemical Journal, Vol. 38, No. 6, P. 527-534, 2004

ABSTRACT

This paper reports a series of studies leading to the discovery of a submarine hydrothermal field (called Nakayama Field) at an arc seamount (12°43′N, 143°32′E) in the southernmost part of the Mariana Trough, western Pacific Ocean. We first detected hydrothermal plumes characterized by water column anomalies of temperature, light transmission, Mn, Fe, Al, O2, CH4, and δ13C of CH4 above the summit caldera of the seamount. Then deep-tow camera surveys confirmed the existence of hydrothermal activity inside the caldera, and an ROV dive finally discovered white smoker-type fluid venting associated with vent fauna. A high concentration of aluminum in the plume and white smoker-type emissions imply acidic hydrothermal activity similar to that observed at the DESMOS Caldera in the eastern Manus Basin, Papua New Guinea. Anomalously low δ13C (CH4) of −38‰ of a vent fluid sample compared to other arc hydrothermal systems along the Izu-Bonin and Mariana Arcs suggests an incorporation of biogenic methane based on a subsurface microbial ecosystem.

KEYWORDS

submarine hydrothermal activity, southern Mariana Trough, hydrothermal plume chemistry, aluminum anomaly, biogenic methane

All Issues

Current Issue:
Stats:
Impact Factor: 1.561
Geochemical Society of Japan

page top