High resolution estimates of paleo-CO2 levels through the Campanian (Late Cretaceous) based on Ginkgo cuticles

Using the stomatal index technique, the Campanian (Late Cretaceous) atmospheric carbon dioxide levels are estimated based on a sequence of fossil cuticles of Ginkgo adiantoides (Ung.) Heer. Ginkgo cuticles were sampled from 11 beds in the Taipinglinchang Formation at Jiayin, Heilongjiang Province, northeast China. In general, the regression function based results show a gradual decrease of pCO2 through Campanian with a background of ∼550–590 ppm. The new data of the Campanian pCO2 are more compatible with GEOCARB II model than those of GEOCARB III, although the new data have slightly higher values (30 ppm on average). A notable short-term carbon dioxide fluctuation (SCDF) is recognized in the upper Campanian (up to ∼690 ppm), and is followed by a rapid return to background values of ∼590 ppm.