HOLOCENE HYDROLOGIC VARIABILITY OF THE EASTERN CARIBBEAN DERIVED FROM SPELEOTHEMS OF THE RECENT TWO MILLENNIA: A PROGRESS REPORT

In order to generate improved climate models of future climate variability, knowledge of past climate and precipitation is essential, especially in the Neotropics where proxies have historically been limited to sediment cores. Speleothems offer the advantage of being absolutely dated using Uranium-series techniques and combined with these dating methods, stable carbon and oxygen isotopes of speleothems can function as effective archives of terrestrial changes in precipitation, vegetation and mean annual temperature. Speleothem archives are relatively well documented throughout Europe and Asia and several records are available from Central and South America, however, as these archives become more abundant, it is becoming clear that there is a necessity for reproducibility among these archives at similar locations.

This study aims to reconstruct hydrologic variability over the recent two millennia using stalagmites from Venezuela and Puerto Rico. Venezuelan stalagmites were collected from the Cariaco Basin terrestrial drainage basin and the geographic climate applicability of the Cariaco Basin data will be tested through comparison with these terrestrial proxies, by analyzing annual, centennial, and millennial-scale variation of ¹⁸O in speleothems. Puerto Rican stalagmites will be compared with the instrumental record and cave monitoring was established in March of 2013. Preliminary analysis of Venezuelan isotopes over the last 600 years shows a drying trend in thhe modern period and solar influence from ~ 330 – 400 yBP.