Metamorphism of the Bikou Group in the Shanxi-Gausu-Sichuan Border Region |
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作者姓名: | Wei Chunjing |
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作者单位: | Wei ChunjingDepartment of Geology,Peking U niversity,Beijing Fei Zhenbi |
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基金项目: | This research is a project(No.49070098)supported by the National Natural Science Foundation of China |
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摘 要: | The Blkou Group on the Shaanxi-Gansu-Sichuan border is composed of Mid-Late Proterozoic metamorphosed bimodal volcanic rocks and flysch sediments. Its metamorphism may be divided into the blueschist and greenschist facies. Three metamorphlc zones, i.e. zones A, B, and C, may be distinguished on the basis of the field distribution of metamorphlc rocks and the variation of b0 values of muscovite. Blueschists are characterized by coexistence of sodic amphiboles and epidote and occur as stripes or relict patches in extensive greenschists of zone A. Studies of metamorphic minerals such as amphiboles, chlorite, epidote and muscovite and their textural relationships indicate that blueschists and greenschists were not formed under the same metamorphic physico-chemical conditions. The blueschist facies was formed at temperatures of 300-400℃ and pressures of 0.5-0.6 GPa. The greenschist facies in zones A and B has similar temperatures but its pressure is only 0.4 GPa or so. The transition from the blueschist to
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Metamorphism of the Bikou Group in the Shanxi-Gausu-Sichuan Border Region |
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Authors: | Wei Chunjing |
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Institution: | Wei ChunjingDepartment of Geology,Peking U niversity,Beijing Fei Zhenbi |
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Abstract: | |
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Keywords: | metamorphic mineral blueschist greenschist metamorphism Bikou Group |
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