Zircon U-Pb Ages and Hf Isotopes of Neoproterozoic Meta-Igneous Rocks in the Liansandao Area,Northern Sulu Orogen,Eastern China,and the Tectonic Implications  

作　　者：Zhaojun Song Huimin Liu Fanxue Meng Xingyu Yuan Qiao Feng Dingwu Zhou Juan Ramon Vidal Romani Hongbo Yan 

机构地区：[1]Shandong Key Laboratory of Depositional Mineralization and Sedimentary Minerals,Shandong University of Science and Technology,Qingdao 266590,China [2]Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266061,China [3]Instituto Universitario de Geologia(Universidad de A Coruna),Campus Universitario de Elvina,15071 Coruna,Spain

出　　处：《Journal of Earth Science》2019年第6期1230-1242,共13页地球科学学刊（英文版）

基　　金：financially supported by the Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology (No. MGQNLM201902);the National Natural Science Foundation of China (Nos. 41472155,41876037);the Scientific and Technological Innovation Project of the China Ocean Mineral Resources R & D Association (No. DY135-N2-1-04);the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents (No. 2016RCJJ008);the SDUST Research Fund (No. 2015TDJH101).

摘　　要：The Sulu Orogen preserves the Neoproterozoic tectonic-magmatic events,corresponding to the breaking up of the Rodinia supercontinent.The ages and petrogenesis of meta-igneous rocks in the Liansandao area in the northern Sulu Orogen are not well-constrained.This study reports zircon U-Pb ages and Hf isotopes of these rocks from the Liansandao area.Three meta-igneous rock samples give similar weighted mean 206 Pb/238 U ages of 744±11,767±12,and 762±15 Ma,respectively,indicating the Neoproterozoic crystallization ages.These rocks formed coevally with the Wulian and Yangkou intrusions that located along the Yantai-Qingdao-Wulian fault zone.The Neoproterozoic ages indicate that the meta-igneous rocks from the Liansandao area have affinity to the Yangtze Block.The three samples haveεHf(t)values of-7.2–-10.5,-6.0–-17.5,and-6.8–-12.0,respectively.These negativeεHf(t)values indicate a primarily crustal source.However,the widely variousεHf(t)values that are higher than the continental crust,suggesting magma mixing between mantle-derived materials and the continental crust or source heterogeneity.Combined with the Hf model ages and geochemical characteristics,the monzodiorite(sample LSD-2)is most likely to be mantle-derived magma then interacted with ancient continental crust,and the granitic protolith(samples LSD-1 and LSD-3)in the Liansandao area might derive from the re-melting of a Paleoproterozoic continental crust at^750 Ma,resulting from the upwelling and underplating of mantle-derived magma formed in an extensional setting due to the break-up of the Rodinia supercontinent.The Sulu Orogen preserves the Neoproterozoic tectonic-magmatic events,corresponding to the breaking up of the Rodinia supercontinent. The ages and petrogenesis of meta-igneous rocks in the Liansandao area in the northern Sulu Orogen are not well-constrained. This study reports zircon U-Pb ages and Hf isotopes of these rocks from the Liansandao area. Three meta-igneous rock samples give similar weighted mean 206 Pb/238 U ages of 744±11,767±12,and 762±15 Ma,respectively,indicating the Neoproterozoic crystallization ages. These rocks formed coevally with the Wulian and Yangkou intrusions that located along the Yantai-Qingdao-Wulian fault zone. The Neoproterozoic ages indicate that the meta-igneous rocks from the Liansandao area have affinity to the Yangtze Block. The three samples have εHf(t) values of-7.2–-10.5,-6.0–-17.5,and-6.8–-12.0,respectively. These negative εHf(t) values indicate a primarily crustal source. However,the widely various εHf(t) values that are higher than the continental crust,suggesting magma mixing between mantle-derived materials and the continental crust or source heterogeneity. Combined with the Hf model ages and geochemical characteristics,the monzodiorite(sample LSD-2) is most likely to be mantle-derived magma then interacted with ancient continental crust,and the granitic protolith(samples LSD-1 and LSD-3) in the Liansandao area might derive from the re-melting of a Paleoproterozoic continental crust at ～750 Ma,resulting from the upwelling and underplating of mantle-derived magma formed in an extensional setting due to the break-up of the Rodinia supercontinent.

关 键 词：NEOPROTEROZOIC ZIRCON U-PB age ZIRCON LU-HF isotope SULU OROGEN 

分 类 号：P58[天文地球—岩石学]