Zircon and Monazite Ages Constraints on Devonian Magmatism and Granulite-Facies Metamorphism in the Southern Qaidam Block:Implications for Evolution of Proto-and Paleo-Tethys in East Asia

作     者：Jin Ba Lu Zhang Chuan He Neng-Song Chen Timothy M.Kusky Qinyan Wang Yusheng Wan Xiaoming Liu 

作者机构：School of Earth SciencesChina University of GeosciencesWuhan 430074China College of Earth ScienceChengdu University of TechnologyChengdu 610059China Sichuan Institute of Geological SurveyChengdu 610081China Center for Global TectonicsChina University of GeosciencesWuhan 430074China Beijing SHRIMP CenterBeijing 100037China State Key Laboratory of Continental DynamicsDepartment of GeologyNorthwest UniversityXi'an 710069China 

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

年 卷 期：2018年第29卷第5期

页      面：1132-1150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：supported by the National Natural Science Foundation of China(Nos.40972042,40772041,42072030) the Open Research Program of the Key Laboratory of Continental Dynamics,Northwest University 

主　　题：zircon and monazite U-Pb geochronology cordierite peraluminous granite low pressure granulite Proto- and Paleo-Tethys evolution East Kunlun-Qaidam. 

摘      要：High-temperature magma generation process and granulite-facies metamorphism can provide important information about mantle-crustal interaction and tectonic evolution. The strongly peralu- minous monzonite pluton, the Jinshuikou cordierite granite on the southern margin of the Qaidam Block, can provide important information about the mantle-crustal interaction and constraints on tectonic tran- sition from Proto-Tethys to Paleo-Tethys. This pluton develops enclaves of mafic granulite, amphibolite and quartzofeldspathic rocks, and is cut by massive monzonitic leuco-granite veins. Zircon and monazite U-Pb dating for the cordierite granite, the granulite enclaves and a massive monzonitic leuco-granite vein reveal that the cordierite granitic magma was generated from Mesoproterozoic continental crust with protolith derived from a provenanee that was composed of 〉2.8 Ga old recycled crustal materials and re- corded a -1.7 Ga magmatic event. The continental crust underwent low-pressure granulite-facies metamorphism at -380 Ma ago, whereas the cordierite granite magmas was generated and emplaced during 380 Ma, followed by intrusion of the massive monzonitic leuco-granite vein at circa 370-330 Ma. These data suggest that after the final closure of Proto-Tethys Ocean spreading along the southern Qaidam Block at -420 Ma, break-off of the subducted slab or delamination of the lower crustal base and upwelling of the asthenospheric mantle beneath the southern Qaidam Block occurred before the Mid-Devonian, and that the initiation of the Paleo-Tethys tectonics might initiate near the end of Early-Carboniferous in the East Kunlun-Qaidam region, East Asia.