caa a22 4500 606149120 CHVBK 20210128100532.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s00531-014-1057-y doi (NATIONALLICENCE)springer-10.1007/s00531-014-1057-y The Mesozoic metamorphic-magmatic events in the Medog area, the Eastern Himalayan Syntaxis: constraints from zircon U-Pb geochronology, trace elements and Hf isotope compositions in granitoids [Elektronische Daten] [Hanwen Dong, Zhiqin Xu, Yuan Li, Zhao Liu, Huaqi Li] Based on the regional geological mapping, several granitoid intrusions had been discovered in the Eastern Himalayan Syntaxis (EHS). In order to constrain their petrogenesis and discuss their relations with the regional tectonics, we carried out U-Pb dating, trace elements and Hf isotope geochemistry studies on zircons separated from the granitoid rocks, in the area of the EHS. In this contribution, the granitoid rocks are mainly composed of diorites (X20-1-6) and granitic gneissic rocks (X2-15-1). The U-Pb zircon dating of diorites yields a crystallization age of 193.8±2.0Ma. These zircon have ε Hf(t) values ranging from −6.48 to −0.05, indicating an involvement of ancient crustal materials in the generation of these igneous rocks. The zircons from the Medog granitic gneissic rock commonly show zoning structures. The REE patterns and abundances of the inherited cores are different from those of the oscillatory rims. The LA-ICP-MS U-Pb zircon in situ analyses indicate that: (1) the zircon cores give multi-stage magmatic event ages ranging from 516 to 1,826Ma, of which six ages are converged on 1,330-911Ma, it is considered that the migmatitic gneiss has been formed in this time, and (2) while the zircon rims yield 206Pb/238U weighted mean ages of 217.4±3.0Ma (MSWD=3.2), which was interpreted to represent the ages of the Triassic anatexis. Their ε Hf(t) values range from −18.98 to −8.36 and −14.22 to 8.72, respectively. The timing of the anatexis in the Medog area is coeval with the widespread metamorphism in Lhasa terrane. Springer-Verlag Berlin Heidelberg, 2014 Mesozoic nationallicence Zircon nationallicence Medog area nationallicence The Eastern Himalayan Syntaxis nationallicence Dong Hanwen State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 100037, Beijing, China aut Xu Zhiqin State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 100037, Beijing, China aut Li Yuan State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 100037, Beijing, China aut Liu Zhao China University of Geosciences (Beijing), 100083, Beijing, China aut Li Huaqi State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 100037, Beijing, China aut International Journal of Earth Sciences Springer Berlin Heidelberg 104/1(2015-01-01), 61-74 1437-3254 104:1<61 2015 104 531 https://doi.org/10.1007/s00531-014-1057-y text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00531-014-1057-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Dong Hanwen State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 100037, Beijing, China aut NATIONALLICENCE 700 1- Xu Zhiqin State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 100037, Beijing, China aut NATIONALLICENCE 700 1- Li Yuan State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 100037, Beijing, China aut NATIONALLICENCE 700 1- Liu Zhao China University of Geosciences (Beijing), 100083, Beijing, China aut NATIONALLICENCE 700 1- Li Huaqi State Key Laboratory of Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, 100037, Beijing, China aut NATIONALLICENCE 773 0- International Journal of Earth Sciences Springer Berlin Heidelberg 104/1(2015-01-01), 61-74 1437-3254 104:1<61 2015 104 531