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Title :Tarama Knoll: Geochemical and biological profiles of hydrothermal activity
Authors :Yamanaka, Toshiro
Nagashio, Hiromi
Nishio, Ryu
Kondo, Kazuna
Noguchi, Takuroh
Okamura, Kei
Nunoura, Takuro
Makita, Hiroko
Nakamura, Kentaro
Watanabe, Hiromi
Inoue, Kazuhiro
Toki, Tomohiro
Iguchi, Kouichiro
Tsunogai, Urumu
Nakada, Ryoichi
Ohshima, Shogo
Toyoda, Shin
Kawai, Jun
Yoshida, Naohiro
Ijiri, Akira
Sunamura, Michinari
Issue Date :10-Jan-2015
Abstract :Tarama Knoll is located about 60 km north of Tarama Island, Sakishima Islands, southwestern Japan. The knoll has an almost conical shape, with foot and summit depths of 2,000 and 1,490 m (total relief = 510 m) from the sea surface, respectively. This area has been identified as a possible active submerged volcano called “Tarama Knoll” (Otani et al. 2004). However, there are actually two separate knolls in the area. This knoll is located northeast of the other, which is named Tarama Hill. During the KT05-26 cruise on the R/V Tanseimaru, a methane anomaly was detected near the seafloor around the area and was considered to be of possible hydrothermal origin. Based on visual observation of the seafloor and its bathymetry, this knoll is considered a pumice cone. Dense turbid water is often observed around summit of the knoll, and a methane anomaly was detected in the water. These observations suggest that the turbid water is a hydrothermal plume. An iron-rich, red-brown sediment-covered area was discovered at a depth of 1,510–1,540 m on the southwestern slope near the summit. At the red-brown sediment area, a weak shimmering of clear fluid could be observed, and the fluid temperature reached 20 °C. Sampled shimmering fluid showed a high silica concentration (≥1 mM), indicating an interaction between the fluid and the surrounding rock. These chemical data support the occurrence of active hydrothermal circulation at Tarama Knoll.
URL :https://doi.org/10.1007/978-4-431-54865-2_40
Type Local :単行書の章
ISBN :978-4-431-54864-5
978-4-431-54865-2
Publisher :Springer Japan
URI :http://hdl.handle.net/20.500.12000/37666
Citation :Subseafloor Biosphere Linked to Global Hydrothermal Systems; TAIGA Concept p.497
Appears in Collections:Peer-reviewed Journal Articles (Faculty of Science)

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