Figure F6. Comparison of Cretaceous ¹⁸O temperature records indicate a 20- to 40-m.y. mismatch between peak Cretaceous–Cenozoic warmth and peak Cretaceous–Cenozoic tectonic CO₂ production inferred from ocean crust cycling (after Wilson et al., 2002). Open symbols = "glassy" foraminifers from the low-latitude western Atlantic, Gulf Coast, and Tanzania. Solid symbols = bulk carbonate from the high-latitude southern Indian Ocean. All temperatures are conservative values calculated assuming w = mean Cretaceous seawater and would be 3°–6°C higher if modern latitudinal trends in w were applied. VPDB = Vienna Peedee belemnite.