Trace element behavior in Miocene I-type and S-type granitic rocks in the Ohmine District, central Kii Peninsula

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Authors:Murata, Mamoru; Yoshida, Takeyoshi
Volume Title:Ganseki Kobutsu Kosho Gakkai-Shi Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists
Source:Ganseki Kobutsu Kosho Gakkai-Shi = Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists, 80(6), p.227-245. Publisher: Nippon Ganseki Kobutsu Kosho Gakkai, c/o: Tohoku Daigaku Rigakubu, Sendai, Japan. ISSN: 0021-4825
Publication Date:1985
Note:In Japanese with English summary. 92 refs.; illus. incl. 6 tables, geol. sketch map
Summary:The Ohmine granitic rocks of Miocene age are divided into S-type and I-type. Abundance of trace elements of these rocks is given as well as petrography and major element abundance. The S-type granitic rocks are higher in SiO2, F and Rb/Sr, and lower in Sr than the I-type rocks. The Shirakura rocks (I-type) formed at an early stage are higher in differentiation index, Ce, Rb and Nb and lower in MgO/(MgO + FeO), Co, Cr, Ni and Sr than the Drogara rocks (S-type). On the basis of these data, the authors discuss the genesis of the granitic rocks. The S-type magma was formed by partial melting of biotite- and orthoclase-bearing sedimentary and/or metasedimentary rocks at approx 700°C and 5 kbar. The I- type granitic rocks would be generated by partial melting of Ca- amphibole and plagioclase-bearing intermediate igneous and/or meta-igneous rocks. Fractional crystallization of plagioclase, Ca-amphibole, and biotite occurred in the I-type magma. Judging from the trace element behaviour, it is unlikely that the granitic rocks are the products of large-scale magma-crust interaction and of mixing between basaltic and granitic magma. The authors also propose a revised classification of calc-alkaline granitic rocks; C-type (sub- to meta-aluminous, SrIo >0.708) and W-type (peraluminous, SrIo <0.708) beside I- and S-type; C-type is not yet found. I- and W-type occur in mature continental regions. S-type occurs in the regions consisting of immature crust without basaltic layer and in the region of crust exceeding 50 km in thickness such as continental margin and continent-continent collision zones. [K.O.]
Subjects:Cenozoic; Chemical composition; Classification; Differentiation; Distribution; Fractional crystallization; Geochemistry; Granites; Igneous rocks; Magmas; Miocene; Neogene; Partial melting; Plutonic rocks; Protoliths; Rb/Sr; Revision; Tertiary; Trace elements; Asia; Far East; Honshu; Japan; Kii Peninsula; C-type; Calk-alkalic composition; Fractionation; I-type; Ohmine; Outer Zone; S-type; W-type
Abstract Numbers:87M/6278
Record ID:1986002136
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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001 1986002136
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005 20190221164915.0
008 190110e198506 ja a 0 0 jpn d
040 |a ViAlAGI  |c ViAlAGI 
041 |a jpn  |b eng 
072 7 |a 05A  |2 georeft 
072 7 |a 02C  |2 georeft 
100 1 |a Murata, Mamoru  |e analytic author 
245 1 0 |a Trace element behavior in Miocene I-type and S-type granitic rocks in the Ohmine District, central Kii Peninsula 
300 |a p. 227-245 
500 |a In Japanese with English summary. 92 refs. 
500 |a Abstract number: 87M/6278 
500 |a Abstractor: K.O. 
500 |a Key title: Ganseki Kobutsu Kosho Gakkai-Shi = Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists 
500 |a Source note: Ganseki Kobutsu Kosho Gakkai-Shi = Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists, 80(6), p.227-245. Publisher: Nippon Ganseki Kobutsu Kosho Gakkai, c/o: Tohoku Daigaku Rigakubu, Sendai, Japan. ISSN: 0021-4825 
500 |a Publication type: journal article 
504 |b 92 refs. 
510 3 |a GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom 
520 |a The Ohmine granitic rocks of Miocene age are divided into S-type and I-type. Abundance of trace elements of these rocks is given as well as petrography and major element abundance. The S-type granitic rocks are higher in SiO<2`, F and Rb/Sr, and lower in Sr than the I-type rocks. The Shirakura rocks (I-type) formed at an early stage are higher in differentiation index, Ce, Rb and Nb and lower in MgO/(MgO + FeO), Co, Cr, Ni and Sr than the Drogara rocks (S-type). On the basis of these data, the authors discuss the genesis of the granitic rocks. The S-type magma was formed by partial melting of biotite- and orthoclase-bearing sedimentary and/or metasedimentary rocks at approx 700°C and 5 kbar. The I- type granitic rocks would be generated by partial melting of Ca- amphibole and plagioclase-bearing intermediate igneous and/or meta-igneous rocks. Fractional crystallization of plagioclase, Ca-amphibole, and biotite occurred in the I-type magma. Judging from the trace element behaviour, it is unlikely that the granitic rocks are the products of large-scale magma-crust interaction and of mixing between basaltic and granitic magma. The authors also propose a revised classification of calc-alkaline granitic rocks; C-type (sub- to meta-aluminous, SrI<o` #GT0.708) and W-type (peraluminous, SrI<o` #LT0.708) beside I- and S-type; C-type is not yet found. I- and W-type occur in mature continental regions. S-type occurs in the regions consisting of immature crust without basaltic layer and in the region of crust exceeding 50 km in thickness such as continental margin and continent-continent collision zones. 
650 7 |a Cenozoic  |2 georeft 
650 7 |a Chemical composition  |2 georeft 
650 7 |a Classification  |2 georeft 
650 7 |a Differentiation  |2 georeft 
650 7 |a Distribution  |2 georeft 
650 7 |a Fractional crystallization  |2 georeft 
650 7 |a Geochemistry  |2 georeft 
650 7 |a Granites  |2 georeft 
650 7 |a Igneous rocks  |2 georeft 
650 7 |a Magmas  |2 georeft 
650 7 |a Miocene  |2 georeft 
650 7 |a Neogene  |2 georeft 
650 7 |a Partial melting  |2 georeft 
650 7 |a Plutonic rocks  |2 georeft 
650 7 |a Protoliths  |2 georeft 
650 7 |a Rb/Sr  |2 georeft 
650 7 |a Revision  |2 georeft 
650 7 |a Tertiary  |2 georeft 
650 7 |a Trace elements  |2 georeft 
651 7 |a Asia  |2 georeft 
651 7 |a Far East  |2 georeft 
651 7 |a Honshu  |2 georeft 
651 7 |a Japan  |2 georeft 
651 7 |a Kii Peninsula  |2 georeft 
653 |a C-type 
653 |a Calk-alkalic composition 
653 |a Fractionation 
653 |a I-type 
653 |a Ohmine 
653 |a Outer Zone 
653 |a S-type 
653 |a W-type 
700 1 |a Yoshida, Takeyoshi,  |e analytic author 
773 0 |t Ganseki Kobutsu Kosho Gakkai-Shi Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists  |d Sendai : Nippon Ganseki Kobutsu Kosho Gakkai, c/o: Tohoku Daigaku Rigakubu, Jun. 1985  |x 0021-4825  |y GKKGA2  |n Ganseki Kobutsu Kosho Gakkai-Shi = Journal of the Japanese Association of Mineralogists, Petrologists and Economic Geologists, 80(6), p.227-245. Publisher: Nippon Ganseki Kobutsu Kosho Gakkai, c/o: Tohoku Daigaku Rigakubu, Sendai, Japan. ISSN: 0021-4825 Publication type: journal article  |g Vol. 80, no. 6  |h illus. incl. 6 tables, geol. sketch map