对混合花岗岩的质疑——论中国大别山地区天堂寨片麻状花岗岩的成因 |
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引用本文:张德全,孙桂英.1991.对混合花岗岩的质疑——论中国大别山地区天堂寨片麻状花岗岩的成因[J].地球学报,12(1):147-158. |
DOI:10.3975/cagsb.xxxx.xx.xx |
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中文摘要:天堂寨片麻状花岗岩,侵位于大别群变质岩系。本文从岩相学、岩石化学、稀土元素地球化学、矿物化学、捕虏体以及矿物之间平衡关系论证了该岩体并非混合交代成因,而是壳源岩浆结晶产物,属I′_u型花岗岩。片麻构造形成与应力作用和塑性变形有关。 |
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A QUERY ON THE ORIGIN OF MIGMATITIC GRANITE ——ON THE GENESIS OF THE TIANTANGZHAI GNEISSIC GRANITE, DABIESHAN, CHINA |
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Abstract:The Tiantangzhai massif, outcropping in the centre of the Dabie mountains region and located to the NE of Luotian county, intruded the meta-morphic rocks of the Dabie Group in Early Cretaceous time. It consists mainly of gneissic biotite monzonitic granite with average SiO2 of 71.7%, Eu/Eu 0.69 and La/Yb 49.39. M' -value of biotite is 47.24-48.1 (M'=Mg ×100/CMg + Fe + Mn + Ti + Al) and KDBi-FeHo is 1.03. It shows that the biotite was in equilibrium with the hornblende during emplacement. The emplacement depth of the massif is more than 10-13km and is the product of crystallization of the crust-derived magma, rather than migmatitic or metaso-matic genesis. It belongs to I'u-type granite. The gneissic structures are formed by the stress and are the results of plastic deformation. |
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