中部地方，第四紀毘沙門岳火山のアダカイト質岩の岩石学

• 氏家 治

  Department of Earth Sciences, Toyama University

• 田中 るみ

  Hydrogen Isotope Research Center, Toyama University

• 渡邊 和徳

  Osaka Branch, Meiji Consultant Co., Ltd.

書誌事項

タイトル別名

• Petrology of adakitic rocks from Quaternary Bishamon-dake volcano, central Japan.

抄録

Quaternary Bishamon-dake volcano, central Japan, is composed of calc-alkalic clinopyroxene-orthopyroxene andesite and dacite with subordinate hornblende andesite having Sr/Y>40, SiO₂ ∼63%, and Al₂O₃ ∼18%. The volcanic rocks are characteristically poorer in incompatible elements such as K₂O and Rb than rocks from the adjacent volcanoes (Dainichi-dake, Eboshi and Washiga-take, Gankyoji, Haku-san, Kyoga-take, and Tomuro). They are essentially mixing products between two magmas; an andesite having SiO₂ ∼60% and higher in FeO.t/MgO (FeO.t denotes total iron as FeO), and an adakite richer in SiO₂ and lower in FeO.t/MgO carrying phenocrysts of orthopyroxene with Mg/(Mg+Fe) ∼0.80 and clinopyroxene with Mg/(Mg+Fe) ∼0.82 and presumed mantle-derived olivine (Fo ∼90) xenocrysts. The end-member andesite magma may have been formed by regional volcanism or lower crustal anatexis, while the end-member adakite magma is likely to have been locally generated beneath Bishamon-dake. The end-member adakite magma had SiO₂>65%, Na₂O≤3.2%, K₂O≤1.2%, Rb≤20 ppm, Y<10 ppm, Nb≤6 ppm, FeO.t/MgO≤1.6 and Sr/Y>60, and was presumably generated by melting of the subducting Philippine Sea plate.

収録刊行物

• 岩鉱

  岩鉱 94 (9), 315-328, 1999

  一般社団法人　日本鉱物科学会

キーワード

• Adakite
• Petrology
• Slab melting
• Philippine Sea plate
• Mantle olivine
• EPMA
• Chemical composition

詳細情報

• CRID: 1390282681211460480
• NII論文ID: 10002698612
• NII書誌ID: AN10047992
• DOI: 10.2465/ganko.94.315
• COI: 1:CAS:528:DC%2BD3cXks1yrsA%3D%3D
• ISSN: 18813275
• ISSN: 09149783
• NDL書誌ID: 4901933
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I4901933
• 本文言語コード: en
• データソース種別:
  • JaLC
  • NDL
  • Crossref
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可