Statistical Treatment of TEX-86 Calibration Dataset

Investigator: 
Courtney Warren
Advisor: 
Mark Pagani
Start Date: 
October, 2011
Description: 

This project involves the assessment of a widely applied paleotemperature proxy known as TEX86. While the application of TEX86 is growing annually, few studies have been aimed at understanding the organisms that produce the compounds used in the proxy, or the conditions that govern their lipid expression. This study seeks to use existing satellite data to ascertain how other variables besides temperature may influence the calibration dataset for TEX86. Satellite data will be collected through the use of ENVI and ArcGIS in the Yale Center for Earth Observation, and multivariate statistical analyses will be used to correlate observed environmental conditions with the lipid relative abundances that constitute the TEX86 measurements

Preliminary statistical analysis on the calibration data set of 427 globally distributed modern samples and ~950 published ancient GDGT samples suggests that more work is needed before TEX86 can be applied to the geologic past with confidence. The distribution of ancient samples can coincide with the modern sample distribution line quite cleanly, but often entire sites will form a secondary distribution, evincing the presence of additional driving factors involved in the production and preservation of GDGTs.