Sapphirine-bearing high pressure marie granulite and its implications in the south Altyn Tagh |
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作者姓名: | ZHANGJianxin MENGFancong |
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作者单位: | InstituteofGeology,ChineseAcademyofGeologicalSciences,Beijing100037,China |
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摘 要: | Sapphirine-bearing high pressure mafic granulites are recognized in the Bashiwake area of the south Altyn Tagh. Mafic granulites and associated peridotites occur as lenses within kyanite-bearing high pressure felsic granulites.Sapphirine occurs as intergrowths with corundum, spine land Ca-rich plagioclase in symplectite in between garnet and clinopyroxene. Reaction textures and mineral compositions indicate that sapphirine-bearing symplectites formed by reactions cons, ruing kyanite, garnet and clinopyroxene.Therefore, both petrographic observations and the mineral compositions suggest that these quartz-free magic granulites had an eclogite origin with an assemblage of garnet clinopyroxene kyanite, which is estimated to be stable at T =1000℃ and P≥2.1 GPa. The sapphirine-bearing symplectites are resulted from isothermal decompression or decompress‘ion with slight cooling during exhumation of the hos trock.
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关 键 词: | 蓝宝石 前寒武层 麻粒岩 岩石 岩层 中国 |
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