Provenance of Late Permian volcanic ash beds in South China: Implications for the age of Emeishan volcanism and its linkage to climate cooling

Hu Huang, Peter A. Cawood, Ming Cai Hou, Shi Jun Ni, Jiang Hai Yang, Yuan Sheng Du, Hua Guo Wen

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21 Citations (Scopus)

Abstract

Whole-rock geochemistry and zircon trace element, U–Pb and Hf isotopic data for Upper Permian volcanic ash at Shangsi show a significant change in source from the Emeishan Large Igneous Province (LIP) to a convergent plate margin magmatic arc. The lower stratigraphic samples display high Al 2 O 3 /TiO 2 ratios, strong negative Eu anomalies, and no depletion in high field strength elements. Zircons with ages of ca. 260 Ma from these ashes have a geochemical affinity to within-plate-type magmas and with felsic ignimbrites from the uppermost part of the Emeishan volcanic succession at Binchuan. These features, combined with relatively high ε Hf (t) values and low Th/Nb ratios in the zircons, imply a late-stage felsic volcanic origin related to Emeishan LIP. The upper stratigraphic samples at Shangsi display significant depletion in Nb and Ti; zircons separated from these volcanic ashes are chemically similar to those from arc-related/orogenic rocks, indicative of a magmatic arc source. Combined with published high-precision CA-TIMS data for these volcanic ash layers, the Emeishan volcanism can be constrained to between ca. 260–257.8 Ma. The age of Emeishan volcanism is consistent with the Wuchiapingian climate cooling event, supporting a potential linkage between these two phenomena.

Original languageEnglish
Pages (from-to)293-306
Number of pages14
JournalLithos
Volume314-315
DOIs
Publication statusPublished - 1 Aug 2018

Keywords

  • Climate cooling
  • Emeishan large igneous province
  • Felsic volcanism
  • Geochemistry
  • Volcanic ashes

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