島弧マグマ供給系の構造と進化

• 吉田 武義

  東北大学大学院理学研究科地球物質科学

• 木村 純一

  福島大学教育学部地学教室地圏環境科学研究室

• 大口 健志

  秋田大学鉱山学部附属素材資源システム研究施設

• 佐藤 比呂志

  東京大学地震研究所

書誌事項

タイトル別名

• Structure and Evolution of Magma plumbing Systems of Island Arc

抄録

Geological and petrological approaches combined with seismological images enable us to discuss the magma segregation and plumbing systems beneath island arcs. The isotopic and primitive magma compositions of the Cenozoic volcanic rocks in the NE Honshu arc suggest the presence of three types of source mantle; the sub-continental and subarc lithospheric mantle, and the subarc asthenospheric mantle (Yoshida et al., 1995). The heterogeneity and across-arc profile of magmatic temperature are closely related to the seismic velocity structure. There is no need to add a slab component to the source of island arc tholeiites in order to explain their isotopic and LILE compositions (Togashi et al.,1992). Three prominent periods of volcanic activity; continental margin, back-arc basin, and island arc stage, are identical in the Cenozoic NE Honshu (Ohguchi et al.,1989). Since the magmatic source regions are considered to be long-lived (Yoshida et al.,1995), they have a strong influence on the distribution and evolution of the volcanoes. Many calderas were formed under a condition of neutral stress field associated with gentle uplift of the axis of NE Honshu arc (Sato and Yoshida,1993). The change in the motion of the Pacific plate occurred at about 4 Ma introduced a large component of compression normal to the Japan trench (Pollitz, 1986). Crustal shortening occurred in the age between 3.5-1.0 Ma is attributable to the change in volcanic activity (Sato and Yoshida, 1993). The NE Honshu arc is divided into four volcanic zones (Nakagawa et al., 1986). The Sekiryo volcanic zone is an axial zone of arc volcanism in which the temperature of magma is the highest, and the eruptive materials are more voluminous than in the other zones. Trace elemental and isotopic data suggest that the associated medium-K CA and low-K TH rock series in the Sekiryo zone were derived from different degrees of partial melting and/or different mantle sources (Yoshida, 1989). The difference of magma emplacement depth can also explain the diversity of CA/TH rock series in andesite compositions. At least four magma chambers, which existed at different depths, are of the requisite to explain the complex magma activities occurred at Ontake volcano in the Late Pleistocene (Kimura and Yoshida, 1993, 1997 a).

収録刊行物

• 火山

  火山 42 (Special), S189-S207, 1997

  特定非営利活動法人 日本火山学会

詳細情報

• CRID: 1390282679280612992
• NII論文ID: 10004493838
• NII論文ID: 110003041112
• DOI: 10.18940/kazan.42.special_s189
• ISSN: 21897182
• ISSN: 04534360
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可