Ferroaxinite and datolite from Mt.Nio,Shizuoka City,central Japan (鮫島輝彦先生追悼論文集)

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概要

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• Ferroaxinite and datolite occur in veins in a dolerite sheet cutting metabasite of the Setogawa Group. The chemical analysis of ferroaxinite is SiO_2 42.40,Al_2O_3 18.30,Fe_2O_3 0.09,TiO_2 0.13,FeO 9.05,MgO 1.51,MnO 0.77,CaO 19.20,B_2O_3 6.37,H_2O^+ 1.33,H_2O^- 0.06,total 99.21% corresponding to ( Ca_<l.94>Mn_<0.06>)_<〓2.00> (Fe^<2+>_<0.71>Mg_<0.21>Al_<0.04>Fe^<3+>_<0.01>Ti_<0.01> )_<〓0.98>Al_<2.00>B_<l.04>Si_<4.00>O_<16>H_<0.84> on the basis of total O = 16. The empirical formula of datolite, derived from the chemical analysis, is very close to the ideal formula CaBSiO_5 (OH) with a slight H_2O excess. Idiomorphic forms of the minerals are exclusively found in voids in veins, although partially developed forms of ferroaxinite are common. Ferroaxinite is tabular with largerr(011) and b(010). Datolite idiomorphs are short prisms with m(110) and s(102) dominant. Associated minerals within and adjacent to veins are quartz, calcite, albite, adularia, chlorite, and bannisterite, together with pumpellyite. In veins ferroaxinite always preceeds datolite in the crystallisation sequence. This is similar to the relationship between manganaxinite and datolite in skarns from some pyrometasomatic ore deposits in Kyushu. Some veins lack ferroaxinite and have pumpellyite instead, drawing attention to the fact that, leaving aside minor differences in H_2O content, subtraction of HBO_2 + SiO_2 from the ferroaxinite formula yields pumpellyite-(Fe^<2+>).

• 静岡大学の論文

著者

• Ono S

  Japex Oman Co. Ltd.

• Sameshima Teruhiko

  Institute Of Geosciences School Of Science Shizuoka University

• ONO Susumu

  Japex Oman Co. Ltd.

• 鮫島 輝彦

  Institute of Geosciences, School of Science, Shizuoka University

関連論文

• Ferroaxinite and datolite from Mt.Nio,Shizuoka City,central Japan (鮫島輝彦先生追悼論文集)

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