北喜马拉雅变质作用和花岗岩研究及其与高喜马拉雅结晶岩系的对比

    The metamorphism and granitic features of the north Himalayas and their comparision with that of the high Himalayan belt REN Liudong

    • 摘要: 沿北喜马拉雅(拉轨岗日山脉)分布一条变质-花岗岩带,其变质级别沿垂直于走向方向呈高低起伏变化,而不是单调递增或递减。花岗岩与围岩以和谐过渡为主,岩体不同部位的矿物、岩石成分均有相当程度的变化,熔融程度较低;而高喜马拉雅花岗岩是低共熔的结果。北喜马拉雅变质-花岗岩带与高喜马拉雅结晶岩相比,从变质作用到岩浆活动均有很大的相似性。本文认为,二者形成的构造环境相似,但时间上又有一定的差异。

       

      Abstract: In the north Himalayas(the Langoi Kangri Mountains )occur a great metamorphic-granite belt,across which the metamorphic grades change oscillatorily,instead of simply progressive in one direction Granites are generally transitional to the country rocks,and the mineral assemblages and chemical compositions of the granites vary substantially from one part to another,suggesting the low degree of partial melting.While that of the high Himalayan leucogranite is of eutectic origin.Compared the metamorphism and magmatic activity with the high Himalayan crystalline rocks,the north Himalayan metamorphic-granite belt bears strong similarities with the high Himalayan belt.The authors duduce that the tectonic settings of the two belts are similar,while the formation time may be different.

       

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