编号：CDUT-2023-53

标题：Crust-derived felsic magmatism in the Emeishan large igneous Province New evidence from zircon U-Pb-Hf-O isotope from the Yangtze Block, China

入藏号：WOS:000788107300002

中国科学院文献情报中心期刊分区：地球科学1区/TOP（2022）

本校作者：邹灏、胡成辉

来源出版物：GEOSCIENCE FRONTIERS  卷: 13  期: 3  文献号: 101369

出版年：2022

第一地址：成都理工大学

关键词：Emeishan Large Igneous Province;Mafic and felsic magmatism;Zircon U-Pb-Hf-O isotopes;Crustal partial melting;Mantle plume

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摘要：Numerous intrusive bodies of mafic-ultramafic to felsic compositions are exposed in association with volcanic rocks in the Late Permian Emeishan large igneous province (ELIP), southwestern China. Most of the granitic rocks in the ELIP were derived by differentiation of basaltic magmas with a mantle connection, and crustal magmas have rarely been studied. Here we investigate a suite of mafic dykes and I-type granites that yield zircon U-Pb emplacement ages of 259.9 +/- 1.2 Ma and 259.3 +/- 1.3 Ma, respectively. The epsilon(Hf)(t) values of zircon from the DZ mafic dyke are -0.3 to 9.4, and their corresponding TDM1 values are in the range of 919-523 Ma. The epsilon(Hf)(t) values of zircon from the DSC I-type granite are between -1 and 3, with TDM1 values showing a range of 938-782 Ma. We also present zircon O isotope data on crust-derived felsic intrusions from the ELIP for the first time. The delta O-18 values of zircon from the DSC I-type granite ranges from 4.87 parts per thousand to 7.5 parts per thousand. The field, petrologic, geochemical and isotopic data from our study lead to the following salient findings. (i) The geochronological study of mafic and felsic intrusive rocks in the ELIP shows that the ages of mafic and felsic magmatism are similar. (ii) The DZ mafic dyke and high-Ti basalts have the same source, i.e., the Emeishan mantle plume. The mafic dyke formed from magmas sourced at the transitional depth between from garnet-lherzolite and spinel-lherzolite, with low degree partial melting (<10%). (iii) The Hf-O isotope data suggest that the DSC I-type granite was formed by partial melting of Neoproterozoic juvenile crust and was contaminated by minor volumes of chemically weathered ancient crustal material. (iv) The heat source leading to the formation of the crust-derived felsic rocks in of the ELIP is considered to be mafic-ultramafic magmas generated by a mantle plume, which partially melted the overlying crust, generating the felsic magma. (C) 2022 China University of Geosciences (Beijing) Published by Elsevier B.V.

文章链接地址: https://doi.org/10.1016/j.gsf.2022.101369