Extended Data Fig. 2: δ13Corg values from previously published PETM and Early Eocene strata relative to terrestrial palynomorph abundance (Arctic Coring Expedition (ACEX), Site M0004a.
From: Shallow-water hydrothermal venting linked to the Palaeocene–Eocene Thermal Maximum
The black (background) line represents the organic matter source mixing line as determined in Sluijs & Dickens33. This line (in ‰) takes the form of ax + b = 0.044 ✕ terrestrial pollen (%) – 27.3. The PETM mixing line is 3.9‰ offset from the Paleocene–Eocene background, reflecting the approximate size of the PETM CIE33. To facilitate comparison with the new isotope data, ACEX data flagged as ‘PETM CIE’ are limited to the interval where Apectodinium augustum occurs consistently31. The Paleocene samples of Unit VI and V (Holes U1568A, U1567B and U1567C) are shown as box-whisker plots (white) and were determined to contain approximately equal proportions of marine and terrestrial organic matter (~50%). The marine-dominated samples (U1567B and U1567C; red box plots) show the expected ~4‰ CIE previously reconstructed for the ACEX samples33.
