著者

Wada Hideki Ohashi Fumio Fujioka Kantaro

出版者

Shizuoka University. Institute of Geosciences

雑誌

Geoscience reports of Shizuoka University (ISSN:03886298)

巻号頁・発行日

vol.20, pp.167-173, 1994-03

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Massive magnesite deposits in the Setogawa Group in Shizuoka were formed by an extensive carbonation of serpentinite in an ancient accretionary prism. Stable isotopic investigations of the origin of massive magnesite deposits revealed that a homogeneous deep-seated magmatic carbon mixing with marine limestones may be the main source of the carbon. Many calcite and dolomite veins occur in the serpentines, basaltic and pelitic rocks and based upon carbon and oxygen isotopes are supposed to be of similar origin to carbonate veins found in modern serpentine diapirs of the Izu-Bonin and Mariana is-land arc. In contrast, massive magnesite deposits were formed during the subduction of an active volcano and/or an active ridge, with circulation of magmatic carbon providing the carbon source for the serpentine diapirs.