GRANULITES OF THE SOUTH MUYA BLOCK (Baikal-Muya Foldbelt): AGE OF METAMORPHISM AND NATURE OF PROTOLITH
S.Yu. Skuzovatov a1, E.V. Sklyarov b c2,3, V.S. Shatsky a d e1,4,5, K.-L. Wang f6, K.V. Kulikova g7, O.V. Zarubina a1
1A.P. Vinogradov Institute of Geochemistry, Siberian Branch of the Russian Academy of Sciences, ul. Favorskogo 1a, Irkutsk, 664033, Russia
2Institute of Earth's Crust, Siberian Branch of the Russian Academy of Sciences, ul. Lermontova 128, Irkutsk, 664033, Russia
3Far Eastern Federal University, ul. Sukhanova 8, Vladivostok, 690950, Russia
4V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
5Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia
6Institute of Earth Sciences, Academia Sinica, 128, Academia Road, Sec. 2, Nangang, Taipei, 11529, Taiwan
7Institute of Geology, Komi Science Center, Ural Branch of the Russian Academy of Sciences, ul., Pervomaiskaya 54, Syktyvkar, Russia
Keywords: Центрально-Азиатский складчатый пояс, Южно-Муйский блок, гранулиты, гранатовые пироксениты, циркон, U-Pb-возраст, континентальная субдукция, Granulites, garnet pyroxenites, zircon, U-Pb age, continental subduction, Central Asian Orogenic Belt, South Muya block
Abstract
High-pressure mafic granulites and garnet pyroxenites occur within the South Muya block as boudins or lenses among metamorphic rocks of the Kindikan Group. Their primary minerals crystallized at 670-750 ºC and 9.5-12.0 kbar. Granulite metamorphism peaked at 630 Ma, according to LA-ICP-MS U-Pb zircon ages. Judging by their major- and trace-element compositions and Hf isotope ratios in zircons, the South Muya granulites were derived from differentiated within-plate basalts, which, in turn, resulted from melting of juvenile mantle source and Meso- or Paleoproterozoic crust. The events of granulite and eclogite metamorphism in the South and North Muya blocks, respectively, were coeval and the two blocks were spatially close to each other at the onset of Late Baikalian subduction and collision events
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