Rekonstruktion der Variabilität des Niederschlags in der Karibik während des letzten Glazials (115.000 - 12.000 Jahre vor heute)

• Antragsteller: Professor Dr. Denis Scholz
• Fachliche Zuordnung: Paläontologie
• Förderung: Förderung von 2013 bis 2017
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 231855229

The tropical hydrological cycle plays a key role in regulating global climate, in particular through the export of heat and moisture to higher latitudes. The climate of the Caribbean and, in particular, precipitation strongly depends on the position of the Intertropical Convergence Zone (ITCZ), which is influenced by seasonal insolation as well as inter-hemispheric spatial gradients in sea surface temperature (SST). The region is also influenced by several large-scale climate patterns, such as the Atlantic Multi-Decadal Oscillation, El Nino and the North Atlantic Oscillation.Several palaeoclimate studies have documented the important role of the position of the ITCZ for Caribbean climate variability during the Holocene. However, for the last Glacial, only a few high-resolution palaeoclimate records from the Caribbean are available.The aim of this proposal is the reconstruction of past precipitation variability in the Caribbean for the Last Glacial period based on speleothems from Puerto Rico and Cuba. Both regions are very sensitive to changes in the position and strength of the ITCZ due to their location at the northernmost boundary of the ITCZ. We will precisely date speleothem growth phases, which reflect past humid phases in the Caribbean, by U-series methods. Furthermore, we will analyse stable oxygen and carbon isotopes as well as various trace elements at decadal to centennial resolution in order to reconstruct precipitation variability during the last Glacial. We will compare these records with supra-regional climate records and the results of climate modelling.In the framework of the DFG SPP INTERDYNAMIK project CaribClim, we have reconstructed past precipitation variability in the Caribbean during the Holocene based on speleothems from Cuba. In 2012, we have initiated another project using remaining funding of CaribClim I and have studied two further speleothems from Cuba (stalagmite Cuba Medio) and Puerto Rico (ENS-2). Both samples grew during the last Glacial, and our preliminary results show several growth phases between 80 and 11 ka. We interpret these growth phases as past humid phases during the last Glacial. In the framework of this project, we plan to study two further large speleothems from Puerto Rico, which grew between 114 and 14 ka, and apply for funding for the years 2013 and 2014 in order to finish the project.

• DFG-Verfahren: Sachbeihilfen
• Beteiligte Person: Professor Dr. Augusto Mangini