AN ISOTOPIC CALIBRATION STUDY OF PRECIPITATION, CAVE DRIPWATER, AND CLIMATE IN WEST-CENTRAL FLORIDA

A calibration study of the stable oxygen and hydrogen isotopes from

precipitation and cave dripwater was conducted in west-central Florida at Legend

Cave during 2007-2008. The amount effect was shown to dominate the area,

with a negative relationship between rainfall amount and the precipitation δ¹⁸O

values. A meteoric water line of 6.7 suggest evaporative effects occur, however

cave dripwater δ¹⁸O values averaged near the mean amount-weighted average of

the precipitation. A weak seasonal influence was observed in the d-excess

values, with summer precipitation being more depleted. Comparison of the

precipitation δ¹⁸O values to synoptic weather data shows the amount effect

dominates due to strong convective storms causing more depleted rainfall in

greater amounts year round. The constant δ¹⁸O values of the dripwater indicate

that speleothem reconstructions in this area would show changes in annual to

interannual scales and would be suitable for long-term, high-resolution studies.