9316597 Cerling The carbon isotopic composition of paleosol carbonate and organic matter can be used to estimate the concentration of CO2 of the ancient atmosphere. Preliminary results indicate that atmospheric P(CO2) was less than 800 ppm V for most of the Tertiary, but was significantly higher during the Mesozoic (2500 to 3000 ppm V). This proposal is to continue to work on estimating the CO2 content of the Paleozoic through Cenozoic paleoatmosphere. We propose to compare the results from paleosols in North America with those in Europe and South America: trends observed on all continents are likely to be global trends.
