2018 ESA Annual Meeting (August 5 -- 10)

PS 54-77 - Estimating temperature at Gray Fossil Site from the paleobotanical record

Friday, August 10, 2018
ESA Exhibit Hall, New Orleans Ernest N. Morial Convention Center
Emily M. B. Simpson, Geosciences, East Tennessee State University, Johnson City, TN
Background/Question/Methods

When active in the latest Miocene and early Pliocene, the Gray Fossil Site in east Tennessee was a flooded sinkhole complex surrounded by a temperate forest dominated by Quercus and Carya. Flora and fauna from the site include taxa whose distributions are limited by cold winter temperatures, suggesting that the region was warmer and wetter during the Miocene and Pliocene; however, climatic parameters have not been quantified. Understanding the climate of the time will allow for better interpretation of the response of Tennessee’s ecosystems to change. Temperature and precipitation are estimated using leaf margin analysis (LMA) and climate leaf analysis multivariate program (CLAMP). Estimates are then compared to modern averages in the region.

Results/Conclusions

LMA predicts a mean annual temperature of 22.86 ° Celsius for the region, while CLAMP predicts 16.62° Celsius with an average annual precipitation of 122.28 centimeters. Although CLAMP estimates are similar to modern averages, the results from leaf margin analysis seemed much higher. It is probable that the real average falls somewhere in between these two estimates. Based on experimental margins of errors for both methods, I estimate that the climate at the Gray Fossil Site during the Miocene and Pliocene would have been roughly 20° Celsius.