Refinement of the Permian–Triassic Boundary Using Integrated Stratigraphic Techniques

The Permian–Triassic Boundary (PTB) marks the most severe mass extinction event in Earth’s history, eliminating approximately 90–95% of marine species and profoundly restructuring terrestrial ecosystems. Accurate delineation of this boundary is essential for understanding the tempo, causes, and environmental consequences of the end-Permian biotic crisis. This study refines the stratigraphic resolution of the PTB through an integrated framework combining biostratigraphy, chemostratigraphy, magnetostratigraphy, and high-precision radiometric dating. The research focuses on well-preserved marine successions, particularly the globally recognized section at Meishan in Huzhou, which serves as the Global Stratotype Section and Point (GSSP) for the PTB. Conodont biozones, especially the first appearance datum (FAD) of Hindeodus parvus, are integrated with carbon isotope (δ¹³C) excursions, mercury anomalies linked to volcanic activity, and magnetostratigraphic polarity reversals. These datasets are further constrained by U–Pb zircon dating of interbedded volcanic ash layers, providing high-resolution temporal calibration. Results demonstrate that the boundary interval is characterized by a sharp negative carbon isotope excursion, abrupt faunal turnover, and synchronous geochemical anomalies that correlate with intensified volcanism associated with the Siberian Traps. The integration of multiple stratigraphic tools reduces chronological uncertainty and clarifies the sequence of extinction pulses and environmental perturbations.