Evaluating the potential of early Pliocene mollusc shells from Peru as El Nino records - permanent "El-Nino-like" state or interannual El Nino variability

• Applicant: Dr. Lars Reuning
• Subject Area: Palaeontology
• Term: from 2006 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 32051613

The interaction between the El Niño-Southern Oscillation (ENSO) and long-term future global warming is uncertain. Some models link past and future ¿hothouse¿ climates to a shallowing of the east Pacific thermocline and a shift towards a permanent ¿El Nino-like state¿ in the east Pacific. This is in contrast to other models indicating little change in the ENSO system under ¿hothouse¿ conditions. The early Pliocene, characterized by prolonged global warmth, provides a good testing ground for these conflictive theories. Since ENSO events are tightly coupled to the annual cycle it is essential to use paleoclimate-archives with seasonal resolution to resolve individual ENSO events. The stable oxygen isotopes of mollusc shells could provide the first proxy-record for ENSO events during the early Pliocene. We will evaluate the potential of different mollusc species, from several Pliocene exposures in coastal Peru, as climate archives. A range of analytical methods (scanning electron microscopy, X-ray diffraction, cathodoluminescence) will be applied to develop a screening procedure for diagenetic modifications. Diagenetically unaltered mollusc shells will be selected for stable isotope analysis of seasonal temperature variability.

• DFG Programme: Research Grants
• International Connection: USA
• Participating Person: Dr. Thomas J. DeVries