Figure 3. Comparison of key Late Cretaceous bottom water and sea surface temperature records.

Benthic and planktonic foraminiferal estimates of temperature have been recalculated using the δ¹⁸O data ofrefs 6,7,12,25 (see Methods for details). Note the Tanzanian planktonic foraminifera12,25 have not been sorted by depth ecology, and consequently the range of SSTs calculated likely encompasses estimates from mixed-layer to thermocline-dwelling species. It is likely that the warmest temperatures are most representative of mixed-layer conditions. SST estimates from metastable carbonates27 have been taken directly from the literature, but note that these estimates are minimum values, based on conservative assumptions of δ_w. SST estimates from published TEX₈₆ data2,24,26 have been recalculated where necessary, using the TEX₈₆^H proxy. The calibration error associated with TEX₈₆^H is ±2.5 °C¹⁴. The Turonian-age data from the Newfoundland margin26 only include data from after Oceanic Anoxic Event 2. Published age-models have been used throughout.