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Formation age, geochemical characteristics and petrogenesis of syenogranite in Chaihe area, central Daxingan Mountains: Constraints on Late Carboniferous evolution of the Xing’an and Songnen blocks

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The tectonic evolutionary history between the Xing’an Block (XB) and Songnen Block (SB) in the eastern Central Asia Orogenic Belt (CAOB) has been hotly debated. In this study, we present a series of new data to provide a better constraint on the magmatic process during plate subduction and its implications for the regional tectonic evolution of XB and SB, even the CAOB. The whole-rock geochemistry and zircon U-Pb chronology of syenogranite in the Chaihe area of the Great Xing’an Range have been carried out. The dating results show that the syenogranite was formed in the Late Carboniferous during the 303.1–316.1 Ma. | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 489-515 http journals.tubitak.gov.tr earth TÜBİTAK Research Article doi 10.3906 yer-2103-4 Formation age geochemical characteristics and petrogenesis of syenogranite in Chaihe area central Daxingan Mountains Constraints on Late Carboniferous evolution of the Xing an and Songnen blocks 1 1 2 1 2 1 Dong-Xue LI Chang-Qing ZHENG Chen-Yue LIANG Xiao ZHOU 1 College of Earth Sciences Jilin University Changchun Jilin China 2 Key laboratory of Mineral Resources Evaluation in Northeast Asia Ministry of Land and Resources Jilin University Jilin China Received 11.03.2021 Accepted Published Online 20.06.2021 Final Version 16.07.2021 Abstact The tectonic evolutionary history between the Xing an Block XB and Songnen Block SB in the eastern Central Asia Orogenic Belt CAOB has been hotly debated. In this study we present a series of new data to provide a better constraint on the magmatic process during plate subduction and its implications for the regional tectonic evolution of XB and SB even the CAOB. The whole-rock geochemistry and zircon U-Pb chronology of syenogranite in the Chaihe area of the Great Xing an Range have been carried out. The dating results show that the syenogranite was formed in the Late Carboniferous during the 303.1 316.1 Ma. The SiO2 content of dated samples is around between 65.43 75.88 while the total alkali content K2O Na2O is 7.23 10.19 the content of MgO 0.07 0.63 and the value of Mg is 0.14 0.36. Moreover they have right-inclined REE distribution patterns La Yb N 1.23 15.61 with slight negative or inappreciable Eu anomalies δEu 0.06 0.49 . All samples were enriched in LILEs e.g. Rb and K and depleted in HFSEs e.g. Nb Ta and Ti . Based on these data combined with their trace element characteristics we conclude that these rocks in our study area were likely derived from partial melting of the crust. Combining with regional tectonic evolution studies and our petrological and geochemical studies