Determining Historic Climates Using Oxygen and Carbon Isotopes Found in Stalagmites

by Eric Gibson

Submitted : Spring 2020

Using oxygen and carbon isotopic data gathered from a stalagmite located in Brooksville, Florida dating back to around 5,300 to 4,200 years ago, the climate was reconstructed using the infamous Dansgaard equation. Through determining the SMOW values for temperatures between 22^oC and 30^oC, recording the PDB values for the amount of oxygen-18 compared to oxygen-16, and converting the PDB values to SMOW values, the temperature could be matched to the correct age of the stalagmite layer. Once the temperatures were found, the ratio of carbon-13 to carbon-12 was recorded as PDB values and compared with the temperature changes in this time period. The average overall daily temperature of the Brooksville area between 5,300 and 4,200 years ago was 26.7^oC with decadal oscillations likely being the cause of rapid changes in the temperature. This recorded average daily temperature was then related to current climates and used as insights to the possible effects of climate change in modern society.

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