PMC

(A) Vertical temperature profile for the site locations. Solid and dashed lines represent latest Paleocene and PETM model estimates, respectively. Data from (A and C) for comparison, including error bars for depth: Morozovella (0 to 30 m), Acarinina (0 to 50 m), (0 m; surface), and benthic (100 to 150 m). (B) Modeled latest Paleocene temperature along an inshore-offshore transect representing the study site. (C) Modeled warming from latest Paleocene to PETM along the same transect. (D) -derived (orange), δ¹⁸O-derived (blue), and Mg/Ca-derived (red) SSTs and modeled Paleocene meridional SST gradient (solid line). Gray dots represent point-by-point model-data comparisons. (E) Interpolated absolute SST reconstructions. (F) Modeled latest Paleocene (2240 ppm) temperatures. (G) PETM absolute SST changes and -derived (orange), δ¹⁸O-derived (blue), and Mg/Ca-derived (red) SST changes between the latest Paleocene and the PETM. Gray dots represent point-by-point model-data comparisons. (H) Interpolated change in absolute SST. (I) Modeled SST change from the latest Paleocene to the PETM (4480 to 2240 ppm). (J) PETM SST changes, normalized to tropical (20°N to 20°S) SST changes (2.7°C) from the data and -derived (orange), δ¹⁸O-derived (blue), and Mg/Ca-derived (red) SST changes between the latest Paleocene and the PETM. Gray dots represent point-by-point model-data comparisons. (K) SST changes from the latest Paleocene to the PETM from the data, normalized to tropical SST changes in the data (2.7°C). (L) SST changes from the latest Paleocene to the PETM, normalized to tropical SST changes in CESM1 (2.4°C). Black circles indicate site locations.

Stratigraphic chart showing the age of Paleocene and Eocene formations of Alabama. Modified from .

Leaf dry mass per area (LMA) of the three Paleocene D1 megafloral associations. (A–C) Comparisons of LMA in the Denver Basin between the Cretaceous and (A) P-D1-West; (B) P-D1-Central; and (C) P-D1-East associations. The Cretaceous species-site pairs are identical to and are identical in all three panels. In the Paleocene, upward facing triangles = early Paleocene D1 (66.04–65 Ma); downward facing triangles = later Paleocene D1 (< 65 Ma). The sum of Paleocene data across all three panels is identical to . (D–F) Cumulative distribution functions of LMA from different temporal groupings in the Denver Basin in (D) P-D1-West; (E) P-D1-Central; and (F) P-D1-East.

Full details of how the 19 Paleocene faunas on which this gradient is based were compiled are given in . Latitudinal gradient for neogastropods only shown in green. Paleolatitudes taken from the Paleobiology Database.