Extended Data Table 1: Key results from individual model runs

From: Very large release of mostly volcanic carbon during the Palaeocene–Eocene Thermal Maximum

Table 1
  1. a, Summary of the main double-inversion experiments carried out. In the experiment identification (ID) column, R07 refers to configurations that tie the Site 401 records to the chronostratigraphy of ref. 25; FE refers to the 3He-based age model of ref. 57; sm refers to the inversion of analytically smoothed δ13C and pH data sets; rw denotes usage of original sample data for double inversions; HI and LO represent potentially extreme configurations that take into account the boron-proxy uncertainty at the 95% confidence level; noW refers to the disabling of silicate (and carbonate) weathering feedbacks; Corg refers to model configurations that allow the removal of excess organic carbon from the surface ocean. Grey shading highlights experiments that are discussed in the text and plotted in Fig. 3. Note that, first, peak emissions are binned at 2-kyr intervals; second, both cumulative emissions and Corg (organic carbon) burial are measured from 40,000 years ago to 190,000 years ago (model time); and third, peak excess weathering reflects carbon removal owing to silicate weathering above pre-PETM weathering rates.
  2. b, Summary table presenting the results of sensitivity experiments (shown in Extended Data Fig. 5) to quantify the importance of uncertainties in the age model for the CIE onset. In these experiments, the CIE onset phase is assumed to occur linearly, with the decline in δ13C and pH varying with a duration of 100 to 20,000 years. Shown are: diagnosed peak carbon emissions; cumulative carbon emissions occurring over the duration of the onset, and mean (flux-weighted) δ13C values for these emissions; cumulative carbon emissions occurring at the 20,000-year time horizon (comparable to the onset duration in our assumed age model), and mean (flux-weighted) δ13C values for these emissions; and cumulative carbon emissions occurring at the 50,000-year horizon, plus the mean (flux-weighted) δ13C values for these emissions. Note that in all experiments, once the onset is complete, the target pH and δ13C values are held constant (and low) until the end of the xperiment (50,000 years).