This project will analyze stable isotopes in planktic and benthic foraminifera at intervals of 3000-5000 years in ODP sites with continuous recovery spanning the Paleocene/Eocene boundary. This time represents an interval of unusually warm global climate, and incorporates at least one dramatic decrease in a 13 C, which has been postulated to indicate massive release of gas hydrates with global warming resulting from input of methane into the atmosphere. The project will (a) determine whether there were several 13 C events, (b) assess the relationship of these events to an evolutionary turnover in marine microorganisms which occurred about 0.5 m.y. later and (c) determine whether there is evidence for precission-driven climate cycles that can be used to improve age-control estimates.