北海道北部, 利尻火山噴出物の岩石学的進化 Petrological evolution of Rishiri volcano, northern Hokkaido, Japan

この論文にアクセスする

この論文をさがす

著者

    • 石塚 吉浩 ISHIZUKA Yoshihiro
    • 北海道大学大学院理学研究科地球惑星物質科学教室 Department of Earth and Planetary Sciences, Graduate School of Science, Hokkaido University
    • 中川 光弘 NAKAGAWA Mitsuhiro
    • 北海道大学大学院理学研究科地球惑星物質科学教室 Department of Earth and Planetary Sciences, Graduate School of Science, Hokkaido University

抄録

Rishiri volcano is an isolated polygenetic volcano that lies at a distance of about 200 km from Quaternary volcanic fields in Hokkaido. The volcanic activity has started abruptly since <0.2 Ma after∼9 My hiatus of volcanism and might have ended since several thousand years ago. The volcanic activity can be divided into three, initial, climactic and final stages in terms of its eruption rate. The climactic stage can be also subdivided into three, C-1, C-2 and C-3 stages in the ascending order.<br>     The eruptive products span from basaltic to rhyolitic rocks (SiO<sub>2</sub>=49.2-73.8%) which can be distinguished by phenocryst assemblages and whole-rock chemistry. Judging from incompatible trace elements, felsic rocks from each stage cannot be formed by fractional crystallization of the basaltic magma and may be produced by crustal melting. Phenocryst assemblage, Ti contents in hornblende, and geological thermometers indicate that magmatic temperature of the dacitic and rhyolitic rocks increases from ∼800°C in the initial stage to ∼1050°C in the C-2 stage, and then decreases to ∼700°C in the final stage. On the other hand, chemical compositions of olivine and spinel suggest that the basaltic magma has also changed its source mantle with the volcanic activity. It can be estimated that the source mantle for the basaltic magmas has changed from fertile peridotites in the initial stage to depleted ones in the climactic stage, and finally changed to fertile ones in the final stage.<br>     The variation in magmatic temperature of the felsic magmas indicates that the volcanic activity with higher eruption rate has produced magma with higher temperature. This suggests that the production of these magma can be explained by ascending and cooling of a mantle diapir which plays as a heat source to melt crustal materials. It can be concluded that the whole-life of Rishiri volcano may be explained by evolution of a single mantle diapir. Our petrological analysis could provide important constraints on modeling magma generation of a polygenetic volcano, because effect of preceding and/or adjacent volcanism is negligible in the case of Rishiri volcano.

収録刊行物

  • 岩鉱 : 岩石鉱物鉱床学会誌 : journal of mineralogy, petrology and economic geology  

    岩鉱 : 岩石鉱物鉱床学会誌 : journal of mineralogy, petrology and economic geology 94(8), 279-294, 1999-08 

    Japan Association of Mineralogical Sciences

参考文献:  43件

参考文献を見るにはログインが必要です。ユーザIDをお持ちでない方は新規登録してください。

被引用文献:  4件

被引用文献を見るにはログインが必要です。ユーザIDをお持ちでない方は新規登録してください。

各種コード

  • NII論文ID(NAID)
    10002603559
  • NII書誌ID(NCID)
    AN10047992
  • 本文言語コード
    JPN
  • 資料種別
    ART
  • ISSN
    09149783
  • NDL 記事登録ID
    4853425
  • NDL 雑誌分類
    ZM46(科学技術--地球科学--岩石・鉱物・鉱床)
  • NDL 請求記号
    Z15-71
  • データ提供元
    CJP書誌  CJP引用  NDL  J-STAGE 
ページトップへ