9304659 Pratt PIs will develop a high-resolution stratigraphic and geochemical framework for the Lower and middle Cretaceous in northern South America, with focus on the Cenomanian-Turonian boundary interval. These data are needed to establish a regional picture of sea level change, primary marine production, and biologic evolution in the Caribbean gateway between the Pacific and the developing Atlantic oceans. Isotopic and geochemical data will be used to calculate the total quantity of marine organic carbon preserved on this margin, making it possible to assess the degree to which the equatorial region influenced global concentrations of carbon dioxide and oxygen in the Cretaceous atmosphere.
