The Emeishan large igneous province (LIP), southwestern China and northern Vietnam, is thought to have been a potential driver for the biotic crises and paleoclimate changes around the Guadalupian-Lopingian boundary (GLB; Permian), but the lack of high-precision radiometric dates to constrain the duration and eruption rates of the volcanism has limited the assessment of their relationship. We present new chemical abrasion–isotope dilution–isotope ratio mass spectrometry U-Pb zircon geochronology of three samples from the lowermost and uppermost parts of the volcanic succession in the central portion of the Emeishan LIP. The results demonstrate that Emeishan volcanism began by 260.55 ± 0.07 Ma and persisted until at least 257.22 ± 0.37 Ma. Combined with a previously published age of 259.1 ± 0.5 Ma for silicic ignimbrites, we estimate that ~85% of Emeishan LIP volume erupted within 1.45 ± 0.50 m.y. Our new results confirm that the Emeishan volcanism began slightly prior to the initiation of the associated mass extinction event and was contemporaneous with the associated warming interval. The new data support the hypothesis that the Emeishan LIP likely triggered the biotic crises and paleoclimate changes around the GLB.

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The southwestern margin of the South China Craton preserves a Late Permian to Early Triassic sedimentary succession, the provenance of which helps to constrain the magmatic history and tectonic evolution of the Paleo-Tethyan Orogen. In this study, we present new detrital zircon U-Pb age, trace element, Hf isotope and whole-rock geochemical composition analyses from the Lower Triassic Qingtianbao Formation, to distinguish the provenance of clastic rocks. The results show that the detrital zircons of the Qingtianbao Formation are characterized by an age spectrum of unimodal, with an age peak of ∼260 Ma, and have a geochemical affinity to within-plate sources. Most of these zircons have positive εHf(t) values (+1.6 to +5.9), similar to those of the Emeishan rhyolites. The whole-rock geochemistry of most clastic samples shows no Nb–Ta anomalies on primitive mantle-normalized elemental diagrams. These features imply a source related to the Emeishan volcanic rocks. Integration of the geologic and provenance records in the southwestern margin of the South China Craton, we suggest that the Paleo-Tethyan Ocean may undergo a unidirectional subduction westward beneath the Indochina Block during the Late Permian–Early Triassic.