Partial Melting Processes During Exhumation of Ultrahigh-Pressure Metamorphic Rocks in Dabieshan, China

作     者：Zhong Zengqiu Zhang Hongfei Suo Shutian You Zhendong(Faculty of Earth Sciences, China University of Geosciences, Wuhan 430074) 

作者机构：Faculty of Earth Sciences China University of GeosciencesWuhan 430074 

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

年 卷 期：1999年第18卷第3期

页      面：194-199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：国家自然科学基金(49794041 49772146) MGMR(9501102) 

主　　题：ultrahigh-pressure metamorphic rocks partial melting Dabieshan 

摘      要：Study practice has proved that the ultrahigh pressure metamorphic rocks iu Dabieshan must have exPerienced botk the retrograde metumorphism and partial melting under decompression and amphibolite-facies conditions during their exhumation from mantel depth to lower-middle *** retrometamorphism and partial melting of the ultrahigh pressure rocks in association with thermal state changing in the middle-lower crust, under amphibolite-facies conditions, are important physical and chemical processes. It would result in a great detrease in the integrated yield strength, and the enhancement of the de formabilitY or the rocks, promoting the transition from contractional (collision) to extensional defoemational regime. The statement of tbe retrometamorphism and partial melting of the ultrahigh pressure rocks has proved the in-site model for the ultrahigh pressure rocks in Dabieshan. It not only clarifies the evolutiou from the UHP eclogite to the surrounding gneissic rock (so called UHP gueiss) and to the garnet-beariug roliated granites (non-UHP country rocks), but also provides scientific arguments for the establiskment of the dynamic model of the exhumation of UHP metamorphic rocks in Dabiesban. In general, Purely conductive heat transfer from the crust itself is probably insurficient to produce temperature conditions for partial melting, and additional heat sources must have been present during partial melting. We infer that the partial melting and extensional flow are probably driveu by delamination and magmatic underplating of thickeued lithospkeric mantle following the continental oblique collision.