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...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 uplift of the plateau since Pleistocene come from the buoyances caused by the compressional stress and mountain root at the margins and by the lithosphere delamination and mountain root in the interior .展开更多
The Tan-Lu Fault was once a transform fault in the Paleotethys, west of which was the Qinling-Dabie Ocean separating the Yangtze Craton from the North China Craton, and east of which was the Su-Lu Ocean separating the...The Tan-Lu Fault was once a transform fault in the Paleotethys, west of which was the Qinling-Dabie Ocean separating the Yangtze Craton from the North China Craton, and east of which was the Su-Lu Ocean separating the Su-Wan Block from the Jiao-Liao Craton. The Qinling-Dabie Ocean closed in the Indosinian orogeny, which created the China-Southeast Asia Subcontinent, with the Tan-Lu Fault becoming a marginal shear zone along the newly-formed amalgamated subcontinent. The Su-Lu Ocean subducted partly in the Indosinian.orogeny, but not closed. In the Jurassic and Early Cretaceous, the Su-Wan Block drifted northwards with subduction of the Su-Lu Ocean and moved westwards to converge the subcontinent by sinistral sheafing of the ENE-striking fractures. The Su-Lu Ocean finally closed and the Su-Wan Block collided with the Jiao-Liao Craton in the Early Cretaceous, which constituted a part of the magnificent interplate Yanshanides. The interplate orogeny rejuvenated the fossil sutures and deep fractures, as well as the Indosinian orogen, and the intraplate （intracontinental） Yanshanian orogeny occurred in the subcontinent. The East Asia Yanshanides, consisting of the interplate orogens in the outer side and the intraplate orogens in the inner side, collapsed quickly in the latest Early Cretaceous and Late Cretaceous. The eastern China area entered a tensile period from the Eogene, and the tectonic differentiation between the central and eastern China areas since the Jurassic was further strengthened.展开更多
基金This study is supported by the Ministry of Geology and Mineral Resources and the National Natural Science Foundation of China
文摘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 uplift of the plateau since Pleistocene come from the buoyances caused by the compressional stress and mountain root at the margins and by the lithosphere delamination and mountain root in the interior .
文摘The Tan-Lu Fault was once a transform fault in the Paleotethys, west of which was the Qinling-Dabie Ocean separating the Yangtze Craton from the North China Craton, and east of which was the Su-Lu Ocean separating the Su-Wan Block from the Jiao-Liao Craton. The Qinling-Dabie Ocean closed in the Indosinian orogeny, which created the China-Southeast Asia Subcontinent, with the Tan-Lu Fault becoming a marginal shear zone along the newly-formed amalgamated subcontinent. The Su-Lu Ocean subducted partly in the Indosinian.orogeny, but not closed. In the Jurassic and Early Cretaceous, the Su-Wan Block drifted northwards with subduction of the Su-Lu Ocean and moved westwards to converge the subcontinent by sinistral sheafing of the ENE-striking fractures. The Su-Lu Ocean finally closed and the Su-Wan Block collided with the Jiao-Liao Craton in the Early Cretaceous, which constituted a part of the magnificent interplate Yanshanides. The interplate orogeny rejuvenated the fossil sutures and deep fractures, as well as the Indosinian orogen, and the intraplate （intracontinental） Yanshanian orogeny occurred in the subcontinent. The East Asia Yanshanides, consisting of the interplate orogens in the outer side and the intraplate orogens in the inner side, collapsed quickly in the latest Early Cretaceous and Late Cretaceous. The eastern China area entered a tensile period from the Eogene, and the tectonic differentiation between the central and eastern China areas since the Jurassic was further strengthened.
