科学前沿

The Carnian Pluvial Episode (CPE) was a major climate change in the early Late Triassic. Multiple ¹³C negative excursions are widely considered to be key indicators of CPE and may be associated with the activity of Wrangellia large igneous province (LIP). However, it is still not clear whether the increased terrestrial inputs due to enhanced hydrological cycle during the CPE disturbed the isotope signal in marine settings. This study analyzed the high-resolution carbon isotopes and element geochemistry of three typical marine section (Xiashulao, Erguan, and Duanqiao) in South China. Decoupling between δ¹³C_carb and δ¹³C_org (2–3 ‰ negative shift of δ¹³C_carb vs 3–4 ‰ positive shift in δ¹³C_org) during CPE is observed at two shallow marine sections, i.e., Xiashulao and Erguan. No decoupling of δ¹³C_carb and δ¹³C_org was found in Duanqiao, which may relate to its location in a deep slope or basin environment, receiving fewer terrestrial inputs. This study reveals the regulating effect of depositional environmental differentiation on the carbon isotope record during the CPE and proposes a model of organic‑carbonate carbon isotope decoupling driven by terrestrial input.