Table 2.

Estimated change in δ¹⁸O_SW and temperature at the Paleocene–Eocene transition in the Clarks Fork and Bighorn Basin

Biozone interval	Δ18OPO4, ‰	Δ18OSW, ‰	ΔT (0.58‰/°C)	ΔT (0.39‰/°C)	ΔT (0.36‰/°C)
This study
Wa-0 to Wa-2	−1.6	−2.1	−3.6	−5.4	−5.8
Cf-3 to Wa-0	+2.2	+2.9	+5.0	+7.4	+8.1
Secord et al. (20)
Cf-3 to Wa-0	+2.1	+2.8	+4.8	+7.2	+7.8
Fricke et al. (17)
Wa-0 to Wa-3a	−1.4	−1.8	−3.1	−4.6	−5.0
Cf-2 to Wa-0	+1.8	+2.4	+4.1	+6.2	+6.7

Based on δ¹⁸O_PO4 of Ectocion (this study), Phenacodus [Secord et al. (20)] and Coryphodon [Fricke et al. (17)], for three different MAT/δ¹⁸O_SW slopes [the modern and two calculated values for early Eocene conditions from Secord et al. (20)].