The Cenozoic geological hallmark of Western Yunnan is the characteristic voluminous Late Cretaceous-Eocene granites;however,their geological background and petrogenesis have not been well constrained and elucidated.In this study,we present new zircon U-Pb dating,along with geochemical and Sr-Nd-Hf isotopic data for granites from the Tengchong-Lianghe granitoid belt(as abbreviated to Tengliang belt)and West Yingjiang batholiths from the Tengchong block.The mineralogical and geochemical features of the Tengliang granites and the West Yingjiang batholiths are ascribed to aluminous S-type granites and weak peraluminous Ⅰ-type,respectively.Zircon U-Pb analyses yielded consistent ages ranging from 67.5 Ma,68.4 Ma and 66.2 Ma from the Tengliang granitoid belt and 50.4 Ma to 60.8 Ma for three samples from the west Yingjiang batholiths.The Tengliang granites were emplaced during the Late Cretaceous(68-66 Ma)and demonstrate negative εHf(t)values(-24 to-4)and initial 87Sr/86Sr ratios of 0.7101-0.7139 and significant negative εNd(t)values from-8.91 to-13.2,indicating a Proterozoic sedimentary source or enriched components.The hornblende-bearing I-type granites from West Yingjiang are characterized by lower initial 87Sr/86Sr ratios of 0.7076-0.7106,compared to Tengliang granite and negative whole-rock εNd(t)values from-4.0 to-11.9.The early Eocene west Yingjiang gneissic granites show wide ranges of εHf(t)values from+7.4 to-8.5 and T2DM of 1.30-0.65 Ga,indicating partial melting of ancient crust with contributions of depleted mantle materials.In combination with the regional background and previous studies,we propose that such a spatio-temporal distribution of the Tengchong granitoid belt might be related to the rollback or angle-switching of the Neo-Tethyan subducting slab.This study sheds new light on the evolutionary history of the Tengchong block.

CHEN Xijie;MENG Yuanku;CAI Zhihui;LI Huaqi;LIU Xiaojia

Development and Research Center of China Geological Survey,Beijing 100037,China;Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources,Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China;State Key Laboratory for Mineral Deposits Research,Nanjing University,Nanjing 210023,China;College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao,Shandong 266590,China

地质学报（英文版）

[1]CHEN Xijie;MENG Yuanku;CAI Zhihui;LI Huaqi;LIU Xiaojia-.Geochemistry and Petrogenesis of Late Cretaceous-Paleocene Granites from the Tengchong Block,Western Yunnan:Implications for Angle-switching of Subducting Slab)[J].地质学报（英文版）,2022(05):1600-1614

Subducting,Lianghe,Tengliang,Yingjiang,batholiths,aluminous,from+7

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