Sea-level control on the Late Permian−Early Triassic continental succession in North China and the role of eustasy and climate change

Continental successions across the Permian−Triassic transition hold essential clues to the environmental cascade that culminated in the greatest mass extinction in Earth history. Here we establish a refined sequence stratigraphic framework for the Late Permian to Early Triassic alluvial−lacustrine strata of the North China Basin, integrating new age constraints, sedimentological observations, and hydrological simulations from the Community Earth System Model. Three third-order depositional sequences are recognized, with boundaries linked to major eustatic falls at the latest Dienerian, earliest Spathian, and latest Spathian, while also reflecting the influence of regional tectonics and paleoclimate. The expected latest Permian sequence boundary is absent; instead, a maximum regressive surface caps a lowstand systems tract, indicating that sea-level drawdown preceded the end-Permian crisis. Our results highlight the interplay among eustasy, tectonics, and climate in shaping continental depositional architecture, and indicate that base-level fall was a contributing factor in the prelude to this crisis.