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Lithium (Li) isotope analyses of sedimentary rocks from the Meishan section in South China reveal extremely light seawater Li isotopic signatures at the Permian-Triassic boundary (PTB), which coincide with the most severe mass extinction in the history of animal life. Using a dynamic seawater lithium box model, we show that the light seawater Li isotopic signatures can be best explained by a significant influx of riverine [Li] with light [[delta].sup.7]Li to the ocean realm. The seawater Li isotope excursion started [greater than or equal to]300 Ky before and persisted up to the main extinction event, which is consistent with the eruption time of the Siberian Traps. The eruption of the Siberian Traps exposed an enormous amount of fresh basalt and triggered C[O.sub.2] release, rapid global warming, and acid rains, which in turn led to a rapid enhancement of continental weathering. The enhanced continental weathering delivered excessive nutrients to the oceans that could lead to marine eutrophication, anoxia, acidification, and ecological perturbation, ultimately resulting in the end-Permian mass extinction. end-Permian mass extinction | Li isotopes | Meishan section | continental weathering | Permian-Triassic boundary

Multiple sulfur isotopes ([sup.32]S, [sup.33]S, [sup.34]S, and [sup.36]S) measured on pyrites from the Penglaitan section, the Global Stratotype Section and Point (GSSP) for the Guadalupian-Lopingian Series boundary, and from the auxiliary Tieqiao section in South China show a sulfur isotope signal of negative and positive [delta][sup.34]S with negative [DELTA][sup.33]S. We suggest that these data indicate mixing of [sup.34]S-enriched and [sup.34]S-depleted sulfur in the sediments, which may have been driven by shoaling of sulfidic waters. Similar isotopic data of negative [delta][sup.34]S with negative [DELTA][sup.33]S were also observed from the EF section in the Delaware Basin of west Texas (USA). The consistency of the minor sulfur isotopic anomalies from both South China and west Texas suggests a causal link between widespread shoaling of sulfidic waters and the end-Guadalupian mass extinction. doi: 10.1130/G37284.1