Multiple sulfur isotope chemostratigraphy across the <scp>Permian–Triassic</scp> boundary at Chaotian, China: Implications for a shoaling model of toxic deep‐waters

Abstract Previous studies on multiple sulfur isotopes ( 32 S, 33 and 34 S) in sedimentary pyrite at the end‐Permian suggested a shoaling of anoxic/sulfidic deep‐water contributing to extinction. This scenario is based an assumption that cycle was largely controlled by benthos activity, though stratigraphic correlation between records ichnofabrics sediments has not yet been examined. We report isotopic composition Permian–Triassic boundary interval Chaotian, South China. Our data can be generally explained mixing sulfide from two different sources: one produced via sulfate reduction open system with respect other closed system. In particular, former substantially low δ S (&lt;−40 ‰) high ∆ (up +0.100 values likely water‐mass or oxic common burrows. The frequent occurrence small framboids (mostly &lt;5 μm diameter) Lopingian (Late Permian) Dalong Formation facies supports enhanced anoxic mass. negative are observed only limestones, no substantial change across extinction horizon despite disappearance bioturbation. results apparently inconsistent previous model. expand model infer that, when sulfidic its rate high, amount hydrogen (H 2 supplied onto shelf shoaling; resulted positive value bulk sediments. variation global scale suggests H concentration and/or upwelling deep‐waters during transition.