Piedrahita, Victor A.Heslop, DavidRoberts, Andrew P.Rohling, Eelco J.Galeotti, SimoneFlorindo, FabioLi, Jinhua2025-12-172025-12-170094-8276ORCID:/0000-0001-8245-0555/work/182268084ORCID:/0000-0003-0566-8117/work/182268351https://hdl.handle.net/1885/733795746The Paleocene-Eocene Thermal Maximum (PETM) was a climate/carbon cycle perturbation recognized in stable carbon isotope (δ13C) records with a negative carbon isotope excursion (CIE). The PETM CIE termination has been associated with a δ13C inflection with pre-PETM-like values referred to as the G point. However, the G point approach has produced variable PETM CIE duration estimates (∼120–230 kyr), which reflects a need to test its reliability. Here, we apply statistical analyses to existing δ13C records and reveal that the G point is sensitive to underlying δ13C uncertainties. We generate a probabilistic-based CIE detection limit, which constrains the time range over which the PETM is detected in δ13C records. This protocol reveals a protracted CIE recovery (>145 kyr) that accounts for a 268.8+21.2/−20.5 kyr PETM CIE duration. Our new duration estimate exceeds previous values, which confirms the potential of extreme carbon cycle perturbations to cause long-lasting carbon cycle disruptions.This study was supported financially by the National Natural Science Foundation of China (Grants 42225402 and W2433104), the Innovation Group Project of Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (Grant 311022004), the Australian Research Council (Grant DP190100874), the China Postdoctoral Science Foundation (Grant 2024M753205), and the Chinese Academy of Sciences through an International Postdoctoral Exchange Fellowship (Talent introduction program) and an IGGCAS International Fellowship for Postdoctoral Researchers. We thank three anonymous reviewers and the editor, Dr Sarah Feakins, for their suggestions that improved this manuscript.10en© 2025. The Author(s).carbon isotope excursion (CIE)Paleocene-Eocene Thermal Maximum (PETM)PETM CIE duration2025-04-1610.1029/2024GL113117105002013958