Under this award the PI will measure 14C in independently dated Peruvian mollusks from multiple time intervals to define long-term trends in upwelling variation. Upwelling is a defining factor of El Nino-southern oscillation (ENSO) in the eastern Pacific, particularly along the coast of Peru. Historical records of this phenomenon are limited and older proxy records in this region are few. The proposal will exploit the ventilation age difference between equatorial surface and deeper upwelled waters. The detection of El Nino events will be made by screening for shell increment alteration and by sequential d18O analysis. The simultaneous excursions in d 18O and D14C in molluscan shell identify periods of upwelling variation caused by El Ninos. By providing data of Peruvian Holocene upwelling this project will provide understanding of paleo-ENSO and give insight into past deep water circulation. Furthermore, the large increase in the database of regional D R data will improve age-dating in many disciplines. Broader impacts of this research also include graduate and undergraduate student training through participation in all stages of research.
