Newly discovered Late Triassic Baqing eclogite in central Tibet indicates an anticlockwise West-East Qiangtang collision.

Autor:	Zhang YX; Asian Tectonics Research Group, College of Earth Science, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China.; Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China., Jin X; Asian Tectonics Research Group, College of Earth Science, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China., Zhang KJ; Asian Tectonics Research Group, College of Earth Science, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China. kaijun@ucas.ac.cn.; Key Laboratory of Computational Geodynamics, Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China. kaijun@ucas.ac.cn., Sun WD; Center of Deep Sea Research, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, 266071, China.; CAS Center for Excellence in Tibetan Plateau Earth Sciences, Chinese Academy of Sciences, Guangzhou, 510640, China., Liu JM; Asian Tectonics Research Group, College of Earth Science, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China., Zhou XY; Asian Tectonics Research Group, College of Earth Science, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China., Yan LL; Asian Tectonics Research Group, College of Earth Science, University of Chinese Academy of Sciences, 19 A Yuquan Road, Beijing, 100049, China.
Jazyk:	angličtina
Zdroj:	Scientific reports [Sci Rep] 2018 Jan 17; Vol. 8 (1), pp. 966. Date of Electronic Publication: 2018 Jan 17.
DOI:	10.1038/s41598-018-19342-w
Abstrakt:	The Triassic eclogite-bearing central Qiangtang metamorphic belt (CQMB) in the northern Tibetan Plateau has been debated whether it is a metamorphic core complex underthrust from the Jinsha Paleo-Tethys or an in-situ Shuanghu suture. The CQMB is thus a key issue to elucidate the crustal architecture of the northern Tibetan Plateau, the tectonics of the eastern Tethys, and the petrogenesis of Cenozoic high-K magmatism. We here report the newly discovered Baqing eclogite along the eastern extension of the CQMB near the Baqing town, central Tibet. These eclogites are characterized by the garnet + omphacite + rutile + phengite + quartz assemblages. Primary eclogite-facies metamorphic pressure-temperature estimates yield consistent minimum pressure of 25 ± 1 kbar at 730 ± 60 °C. U-Pb dating on zircons that contain inclusions (garnet + omphacite + rutile + phengite) gave eclogite-facies metamorphic ages of 223 Ma. The geochemical continental crustal signature and the presence of Paleozoic cores in the zircons indicate that the Baqing eclogite formed by continental subduction and marks an eastward-younging anticlockwise West-East Qiangtang collision along the Shuanghu suture from the Middle to Late Triassic.
Databáze:	MEDLINE
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