CONCENTRATION OF CARBON-DIOXIDE IN THE LATE CRETACEOUS ATMOSPHERE

Stable carbon isotope data from Late Cretaceous (Maastrichtian) palaeo sols in India are used to estimate the concentration of carbon dioxide in the Late Cretaceous atmosphere. We show that the Maastrichtian atm osphere is unlikely to have contained more than about 1300 ppm by volu me of CO2, This value agrees with an independently modelled value of C O2 in the Late Cretaceous atmosphere. A low concentration of the green house gas carbon dioxide in the Maastrichtian atmosphere (relative to concentrations in the earlier Cretaceous) is consistent with palaeotem perature information from terrestrial plant and marine fossils, which suggest that the global climate cooled toward the end of the Cretaceou s Period.