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Data from: Petrogenetic studies of Permian pegmatites in the Chinese Altay: implications for a two-stage post-collisional magmatism model

Cite this dataset

Wang, Mengtao (2022). Data from: Petrogenetic studies of Permian pegmatites in the Chinese Altay: implications for a two-stage post-collisional magmatism model [Dataset]. Dryad. https://doi.org/10.5061/dryad.xksn02vk0

Abstract

Understanding the petrogenesis of rare-metal pegmatites is important for understanding ore-forming processes and their tectonic settings. In this study, we performed zircon U-Pb geochronological and Hf-O isotopic analyses of the Xiaokalasu (XKLS), Dakalasu (DKLS) and Yelaman (YLM) pegmatites in the Chinese Altay orogen. These pegmatites have low εHf(t) values (-0.6 ~ +4.3), two-stage model ages of 989 ~ 1293 Ma, and high δ18O values (+6.52 ~ +11.31), indicating that they may have been derived from the anatexis of mature sedimentary rocks in the deep crust, with a small amount of mantle-derived or juvenile material. Geochronological and Hf-O isotopic data for granitic intrusions in the Chinese Altay Mountains indicate that the εHf(t) values decreased from the Permian to the Triassic, which implies that two-stage post-collisional magmatism occurred in this region. During the Permian, the thin lower crust was cold; thus, magmatism likely originated in the deep crust close to the Moho surface and involved intense mantle-crust interactions. During the Triassic, asthenospheric upwelling provided heat to the lower crust, which increased the geothermal gradient and led to the anatexis of shallow crustal material.

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Funding

Key Program of National Natural Science Foundation of China, Award: 91962222

Guizhou Provincial 2019 Science and Technology Subsidies, Award: GZ2019SIG

Strategic Priority Research Program (B) of the Chinese Academy of Sciences, Award: XDB18000000