Holocene Hydrologic Variability of the Eastern Caribbean Derived from Speleothems of the Recent Two Millennia: a Progress Report
Abstract
To improve models of future climate variability, knowledge of past temperature and precipitation is essential, especially in the Neotropics where proxies have been historically limited to sediment cores. Speleothems offer high resolution dating using uranium-series techniques, and in combination with stable carbon and oxygen isotopes 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 as well as Central and South America to the extent that replication is possible among archives at nearby locations. This study aims to reconstruct hydrologic variability over the recent two millennia using two stalagmites each from Venezuela and Puerto Rico. The Venezuelan stalagmites were collected from Cueva Camillo within a Cariaco Basin terrestrial catchment. Preliminary analysis of Venezuelan stalagmite VECA1a stable oxygen isotopes over the last 600 years shows increasing precipitation from ~300 - 588 yBP and comparison with Cariaco Basin titanium concentrations and planktonic foraminifera oxygen isotopes show a weak correlation. Spectral analysis reveals solar influence from ~ 330 - 400 yBP and also appears to be influenced by the Atlantic Multidecadal Oscillation (AMO) from ~ 350 - 400 yBP and from ~550 - 588 yBP where the record terminates at a hiatus. Further examination of the geographic climate applicability of this locale's data will be tested through comparison with these terrestrial proxies, by analyzing annual, centennial, and millennial-scale variation of 18O in speleothems. The Puerto Rican stalagmites will be compared via dating and stable isotope analysis with Venezuelan stalagmites, as well as the local instrumental record. Cave monitoring of parameters at Cueva Dos Ojos (Puerto Rico) include temperature, relative humidity, spot pCO2 measurements, drip rate and drip water chemistry. Monitoring initiated in March of 2013 has already detected seasonality, and is expected to provide insight to the isotopic signature of speleothems collected there.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMPP51A1944S
- Keywords:
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- 1616 GLOBAL CHANGE Climate variability;
- 1650 GLOBAL CHANGE Solar variability;
- 1620 GLOBAL CHANGE Climate dynamics