Determining Past Climate from Isotopic Analysis of Speleothems

by Jessica Aguilar

Submitted : Spring 2015

The objective for this project was to use speleothems (specifically stalagmite cores from a local cave) as a proxy to determine the past climate of Brooksville, Florida from 4000 years ago to 6000 years ago. Specifically, using isotopic analysis of ¹⁶O and ¹⁸O ratios (obtained from a mass spectrometer) to determine whether rainfall or temperature had more impact during this time period. The lowest approximate vPDB value was discovered along with the approximate highest vPDB value, they were converted to vSMOW. Then, the Dorale equation was used until the matching temperatures to the (highest and lowest) vSMOW values were discovered. Due to the fact that the difference between 30.9 ˚C and 20.8 ˚C is 10.1 which is greater than 10, we can concluded that rainfall had more of an impact than temperature did in Brooksville, Florida from 4000 years ago to 6000 years ago. 

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