COMPARATIVE OPTICAL DATING TECHNIQUES IN DETERMINING THE AGE OF COPPICE DUNES ON THE MESCALERO SAND SHEET, SOUTHEASTERN NEW MEXICO

Coppice dunes on the Mescalero Sand Sheet form around Torrey mesquite that populated the area after American settlement in Southeastern New Mexico. The dune age is constrained by 14C dating on the underlying Loco Hills soil and by previous 137Cs radioactive isotope analysis in the upper 22 cm of the dune. The optical age was determined from a sample from 1.0m depth using the Single Aliquot Regenerative Dose (SAR) technique. Because data from small aliquots showed evidence of partial bleaching, the Leading Edge model, and the Minimum Age Model were applied to large data sets, and produced ages consistent with the 137Cs data. Comparative data were collected using the single-grain optically stimulated luminescence (OSL) technique.