Intracontinental Orogenic Igneous Rocks and Orogenic Processes in Qinghai-Xizang-Himalaya

作     者：Deng Jinfu Zhao Hailing Lai Shaocong Li Yuwen Liu Houxiang Mo Xuanxue Di YongjunDepartment of Geology and Mineral Resources , China University of Geosciences , Beijing 100083 

出 版 物：《Journal of Earth Science》 (地球科学学刊（英文版）)

年 卷 期：1995年第14卷第2期

页      面：5-12页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

基　　金：This study is supported by the Ministry of Geology and Mineral Resources and the National Natural Science Foundation of China 

主　　题：intracontinental orogeny . paired igneous rock zone . orogenic process 

摘      要：Based on the discussion on the intracontinental orogenic igneous rocks formed after India-Asia collision (40 or 45 Ma),the intracontinental orogenic processes of Qinghai-Xizang (Tibet )-Himalaya are traced . Muscovite/two mica granite is considered as a petrological record of intracontinental subduction. Volcanic rocks of shoshonite series are believed to be the products of the orogenic and outside cratonic lithosphere convergence . The intracontinental orogenic igneous rocks are developed only on the margins of the orogenic belt. The pairing phe nomenon of the igneous rock zones is regarded as one of the best signs to recognize the special range of orogenic belt . The stage of magmatic activity is a representation and indicator of orogenic episode . Three pairs of the igneous events in Oligocene , Miocene and Pleistocene and their space distribution indicate three corresponding orogenic episodes and the horizontal expansion across the orogenic belt , respectively . On the northern and southern margins of the orogenic belt are always developed the volcanic eruption of the shoshonite series and the muscovite two mica granite intrusion ,indicating the different nature of the margins .In the former case the colder crust and hotter mantle . as well as the double crust resulted from the horizontal shortening are developed , and in the latter case the hotter crust and colder mantle , the double crust by the overlapping of two crusts are formed . During the Pleistocene orogenic episode the interior of the orogenic belt , i. e. the Gandise - Qiangtang might be going to the stage of the orogenic collapse . and the compressional orogeny might occur only at both the mar gins . The orogenic processes mentioned above show that beneath the Qinghai - Xizang (Tibet ) Himalaya,the deeper mantle has been always undergoing a descending convergence , rather than the simple orogeny resulted from the underthrusting of the India continent only . The dynamic forces that results in rapid up