UMR CNRS 5805 EPOC
Environnements et Paléoenvironnements
Océaniques et Continentaux

        

Consignes de Sécurité et Numéros d'Urgence
(à l'usage des personnels du laboratoire)

November 19, 2010  10:45 am

Lieu Salle Stendhal, DGO, Bâtiment B18 Intervenant(s) Alexander CORREA-METRIO, Department of Biological Sciences, Florida Institute of Technology, USA

The climate of the Neotropics varied significantly in glacial times, but the timing, duration, and magnitude of changes remain unknown. Furthermore, the impact of extreme events that induced periods of exceptional climate change has not been determined. Lake pete-Itza (core PI-6), Guatemala, provides a 86,000-year continuous sedimentary record of the Central American lowlands. Fossil and modern pollen analyses were used to reconstruct air temperature changes for the region. Changes in the Atlantic circulation, migration of the ITCZ, and insolation seasonality influenced the climates and the vegetation of the area. Low-magnitude temperature changes were associated with Dansgaard-Oeschger cycles and Heinrich Events, with significant coolings almost exclusively associated with the latter. Warming rates predicted for the 21st century had no precedent during the last 86,000 years. The temperature record of Lake Peten-Itza evidenced that the area is tightly linked to the interhemispheric climatic system at millennial and centennial scales.