科学前沿

The Permian-Triassic transition, marked by Earth's largest mass extinction and intensive volcanisms, represents a critical interval for understanding global environmental crises and biotic turnovers. Magnetostratigraphy provides a unique tool for correlating marine and terrestrial records, yet inconsistencies in polarity sequences and limited chronostratigraphic precision have hindered robust global correlations. Here we synthesize and rigorously evaluate magnetostratigraphic data across the late Lopingian (Late Permian) to the earliest Triassic from China, North American, central European Basin, Karoo Basin, East European Platform and Siberian Trap suites — using a unified reliability framework (M-value ≥4). Our reanalysis reveals that the late Permian Changhsingian Stage is dominated by normal polarity magnetozones (P1n to P5n from younger to older), intercalated with four short reversed polarity intervals (P1r to P4r from younger to older). The base of normal polarity interval P1n is interpolated to be ∼252.2 Ma. The end-Permian mass extinction and Permian-Triassic boundary are thus placed in the lower part of the normal magnetozone P1n. Three additional magnetozones (T1r, T1n and T2r from younger to older) are recognized in the earliest Triassic Induan Stage. The distinct normal polarity P1n across the Permian-Triassic boundary can serve as a potential marker for improving correlation of the Permian-Triassic interval between marine and non-marine sequences. In future, improved measurement technology for isolating primary remanent magnetizations, more rigorous cross-checking of high-resolution magnetostratigraphic sequences and high-precision geochronological constraints are necessary to refine a reliable magnetostratigraphic timescale during the Permian-Triassic transition.