Geochronological and geochemical constraints on the heat source of thermal activity in the Rausu geothermal field, Shiretoko Peninsula, Hokkaido, Japan

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概要

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• The Rausu geothermal field is situated in the middle part of the Shiretoko Peninsula, east Hokkaido, Japan. It has been classified into “A-type” (characterized by high temperature/depth ratio) in terms of its Geothermal Activity Index. The geology of the area consists of Tertiary volcaniclastic rocks, a hornblende dacite intrusion and overlying Tertiary to Quaternary lavas. The dacite is 63 wt.% SiO2 and belongs to the calc-alkaline suite. The solidus and subsolidus temperatures of the dacite magma, calculated from mineral equilibrium, are 830°C and 741°C, respectively. The K-Ar age obtained from hornblende phenocryst is 3.0±0.8 Ma. The geological, geochronological and petrological data suggest that the heat source of the Rausu geothermal field is a long-lived, high-temperature granodioritic pluton existing beneath the intrusion. It is suggested that the thermal activity is caused by the upwelling of high-temperature fluids related to the pluton, through fracture networks within or around the intrusion.

• 2002-06-01

著者

• Goto Yoshihiko

  Department Of Geoscience And Technology Graduate School Of Engineering Tohoku University

• Kono Tatuzo

  Department Of Geoscience And Technology Graduate School Of Engineering

• TSUCHIYA Nobutaka

  Department of Geology, Faculty of Education, Iwate University

関連論文

• K-Ar ages of the Akan-Shiretoko volcanic chain lying oblique to the Kurile trench : Implications for tectonic control of volcanism
• Middle Miocene to Quaternary primary basalt and high magnesian andesite magmas of North Hokkaido, Japan : Source mantle characteristics and degrees of partial melting
• Formation process of branches of needle ice crystals grown from vapor
• Geochronological and geochemical constraints on the heat source of thermal activity in the Rausu geothermal field, Shiretoko Peninsula, Hokkaido, Japan
• Internal structures of a subaerial dacite cryptodome at Usu volcano, Hokkaido, Japan (特集 2003年度実施の地域との共同研究の報告)

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