Assessing the Duration of the Paleocene-Eocene Thermal Maximum

The Paleocene-Eocene Thermal Maximum (PETM) was a climate/carbon cycle perturbation recognized in stable carbon isotope (delta C-13) records with a negative carbon isotope excursion (CIE). The PETM CIE termination has been associated with a delta C-13 inflection with pre-PETM-like values referred to as the G point. However, the G point approach has produced variable PETM CIE duration estimates (similar to 120-230 kyr), which reflects a need to test its reliability. Here, we apply statistical analyses to existing delta C-13 records and reveal that the G point is sensitive to underlying delta C-13 uncertainties. We generate a probabilistic-based CIE detection limit, which constrains the time range over which the PETM is detected in delta C-13 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.