摘要
Panzhihua-Xichang (Panxi) micro-palaeoland is the oldest terrane on the western margin of the Yangtze Block. Some intermediate-basic granulites are considered to be the crys-talline basement of lower crust in the terrane. Granulite-facies metamorphism of the granulites was developed in the period from 1186 Ma to 1128 Ma. The origin of granulites was related to the collision orogenic process occurring when the micro-palaeolands merged to form the Rodinia Supercontinent. Amphibolite-facies retrogressive metamorphism of granulites took place in the period from 877 Ma to 825 Ma. This period was consistent with the breakup time of the Rodinia Supercontinent. 40Ar/39Ar ages and fission track (FT) ages of granulites in the Panxi mi-cro-palaeoland show that the vertical movement history of crustal rocks was a slow uplift process of the rigid terrane in the time from Neoproterozoic to Mesozoic. The subduction of India Plate towards Euroasia Plate resulted in the rapid uplift of the Qinghai-Tibetan Block in Cenozoic. Meanwhile, the Qinghai-Tibetan Block moved towards east. Consequently the Panxi terrane was uplifted rapidly. As a result of the collision orogeny between the Qinghai-Tibetan Block and the Panxi terrane, the granulite-facies crystalline basement in this region was exhumed and exposed to the surface.
Panzhihua-Xichang (Panxi) micro-palaeoland is the oldest terrane on the western margin of the Yangtze Block. Some intermediate-basic granulites are considered to be the crystalline basement of lower crust in the terrane. Granulite-facies metamorphism of the granulites was developed in the period from 1186 Mato 1128 Ma. The origin of granulites was related to the collision orogenic process occurring when the micro-palaeolands merged to form the Rodinia Supercontinent. Amphibolite-facies retrogressive metamorphism of granulites took place in the period from 877 Ma to 825 Ma. This period was consistent with the breakup time of the Rodinia Supercontinent. 40Ar/39Ar ages and fission track (FT) ages of granulites in the Panxi micro-palaeoland show that the vertical movement history of crustal rocks was a slow uplift process of the rigid terrane in the time from Neoproterozoic to Mesozoic. The subduction of India Plate towards Euroasia Plate resulted in the rapid uplift of the Qinghai-Tibetan Block in Cenozoic. Meanwhile, the Qinghai-Tibetan Block moved towards east. Consequently the Panxi terrane was uplifted rapidly. As a result of the collision orogeny between the Qinghai-Tibetan Block and the Panxi terrane, the granulite-facies crystalline basement in this region was exhumed and exposed to the surface.
作者
XU Shijin1, LIU Wenzhong1, WANG Rucheng1, YU Hangbo1, LI Daming2, WAN Jinglin2 & FANG Zhong1 1. Department of Earth Sciences and State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 210093, China
2. Institute of Geology, China Seismological Bureau, Beijing 100029, China
基金
This work was supported by the National Natural Science Foundation of China(Grant No.49972062)
by the Ministry of Education(Grant No.104089).
