SUB-ANNUAL VARIATION OF STABLE OXYGEN ISOTOPES IN O. VIRGINIANUS TOOTH ENAMEL AS A PROXY FOR SEASONALITY: A CASE STUDY FROM SINGER MOYE MOUNDS, GEORGIA

Stable isotope analyses of herbivore tooth enamel have proven useful for interpreting diet and environmental conditions in both modern and archeological specimens. However, white-tailed deer (O. virginianus) remain under-studied in this respect despite their ecological ubiquity in North America. Deer populations share historic proximity to human settlements, particularly in the southeast, where deer were a primary resource for the Muscogee People. Singer Moye, one of the largest Muscogee mound sites in Georgia, is comprised of midden deposits containing faunal remains that coincide with the onset of the Little Ice Age (1400 ­– 1700 AD). Generally characterized by severe winters and mild summers throughout the northern hemisphere, this unique climatic interval is poorly constrained in the southeastern US. Stable isotopic analyses of deer enamel from midden deposits may be a powerful proxy for the reconstruction of regional seasonality in this period. Previous work with O. virginianus examined stable isotopes in bone collagen to elucidate deer diet and climatic variables like precipitation. Though informative, bone collagen ultimately lacks the temporal resolution of tooth enamel, which mineralizes sequentially and is resistant to diagenesis. In O. virginianus, M2 and M3 molars archive sub-annual variation in δ¹⁸O_carb across approximately one year, recording changes in seasonality. Because deer ingest water through mostly broad-leafed vegetation, enriched δ¹⁸O_carb indicates stronger evapotranspiration. Thus, the range of δ¹⁸O_carb values convey changes in precipitation and temperature that effect the total evapotranspiration across a year. We interpret relatively small ranges of δ¹⁸O values across the year as dampened seasonality and large ranges as strengthened seasonality. We present preliminary δ¹⁸O_carb data on several M2 and M3 pairs from a Singer Moye midden to reveal snapshots of seasonality during the late Mississippian Period and the onset Little Ice Age in the southeast.