Petrogenesis and tectonic implications of the Eocene-Oligocene potassic felsic suites in western Yunnan, eastern Tibetan Plateau: Evidence from petrology, zircon chronology, elemental and Sr-Nd-Pb-Hf isotopic geochemistry

Abstract

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Chronological and Geochemical Study of the Cenozoic Potassic Felsic Igneous Rocks in Western Yunnan, SE Tibet: Implications for their Tectonic Mechanisms

“…Table 2) and exhibit Sr-Nd isotopes similar to those of coeval mafic magmas sourced from the lithospheric mantle (Fig. 8a; Lu et al, 2013;He et al, 2016;Tong et al, 2019;Wang et al, 2020).…”

“…1b, 6), implying a potential spatiotemporal relation; (2) these syenitic porphyries show coherent and parallel REE and (Middlemost, 1994); the dashed line separating the alkaline series from the subalkaline series is from Irvine and Baragar (1971); (b) K 2 O vs. SiO 2 (Peccerillo and Taylor, 1976); (c) A/CNK vs. SiO 2 (Kemp et al, 2006). Data sources: contemporaneous potassic mafic rocks in western Yunnan from Xu et al, 2001;Guo et al, 2005;Huang et al, 2007;Huang et al, 2010;Li et al, 2010;Jia et al, 2013;Lu et al, 2015; the coeval felsic intrusions in western Yunnan from Lu et al, 2013;He et al, 2016;Tong et al, 2019;and Wang et al, 2020. trace-element patterns to those of coeval mafic suites (Figs. 5, 7), reflecting a continuous evolutionary relationship between them; (3) the syenitic porphyries from the studied region show high bulk-rock zircon saturation temperatures (740-774°C) (Suppl.…”

“…Fields for western Yunnan potassic mafic rocks are from Zhang and Xie, 1997;Ying and Cai, 2004;Guo et al, 2005;Xu et al, 2006;Huang et al, 2007;Xia et al, 2007;Huang et al, 2010;Jia et al, 2013;and Lu et al, 2015; those for potassic felsic rocks are from Deng et al, 1998a;Liu et al, 2003;Wang, 2003;Dong et al, 2005;Peng et al, 2005;Liang et al, 2007;Lu et al, 2012;He et al, 2016;Tong et al, 2019;Wang et al, 2020;. 1999;Liang et al, 2007), accompanying reactivation of some pre-existing lithospheric faults (Schä rer et al, 1984;Tapponnier et al, 1990;Leloup et al, 1995).…”

Petrogenetic evolution of the Zhuopan potassic alkaline complex, western Yunnan, SW China: Implications for heterogeneous metasomatism of lithospheric mantle beneath Simao and western Yangtze block

“…Zircon Hf isotopes of Zhuopan alkaline rocks recorded T DM model ages much older than crystallization age (Table S3), indicating that the mantle source has been modified to long-term low Lu/Hf ratios attributed to ancient metasomatic processes. It has been considered that the western Yangtze block underwent Proterozoic subduction before 900 Ma (Chen et al, 2017a;Gan and Huang, 2017;He et al, 2016;Tong et al, 2019), while the margin of Simao-Indochina block experienced a long-lived double-sided subduction during the evolution of the Protoand Paleo-Tethys Ocean (460-280 Ma), according to arc magmatic rocks (Lai et al, 2014;Li et al, 2012;Nie et al, 2015). Huang et al (2010) argued that the Emeishan Large Igneous Province (ELIP) whose inner zone is located in western margin of the Yangtze block (Fig.…”

Petrogenesis of the Late Eocene to Early Oligocene Yao'an Shoshonitic Complex, Southeastern Tibet: Partial Melting of an Ancient Continental Lithospheric Mantle beneath the Yangtze Block

“…Numerous Cenozoic potassic-ultrapotassic rocks have been identified on the Tibetan Plateau and its southeastern margin, which provide geological records of the India-Eurasia collision/subduction (e.g., Mo et al, 1993;Chung et al, 2005;Deng et al, 2014;Guo and Wilson, 2019;Dong et al, 2022). Given their geodynamic implications, much geochronological, geochemical and zircon Hf-O isotopic data have been published on them (e.g., Ding et al, 2016;Wang et al, 2018Wang et al, , 2022Tong et al, 2019;Liao et al, 2020;Shen et al, 2021;Chen et al, 2022;Li et al, 2022;Liu et al, 2023). These data demonstrated that each potassic-ultrapotassic body in SE Tibet appears to be unique, and no single petrogenetic model can be universally applied to them.…”