SIMS reveals Diagenesis and Seasonal Paleoprecipitation: A New Method for Reconstructing Past Environments

Summary

One goal of zooarchaeological inquiry is to reconstruct past environments. This presentation will highlight a new method to identify paleoprecipitation records from the stable oxygen isotope values (δ18Oen) recorded in tooth enamel. Seasonal rainfall patterns are reconstructed using a secondary ion mass spectrometer (SIMS) to generate high-resolution serial spot analyses (13 µm spots) of δ18Oen. Additionally, this presentation will address the specific issue of identifying diagenesis (post-depositional alteration) in tooth enamel, a material that has long been assumed to be resistant to diagenesis. Previous research identified chemical changes the tooth enamel crystal structure using cathodoluminescence (CL). It is unclear whether changes identified by CL correspond to altered isotope ratios in the enamel. It was not until technological advancements with instrumentation, such as the SIMS, that the question of diagenesis in enamel could be addressed directly because oxygen isotope values could not be measured at a high enough resolution to test this question. The aim of this research project is to identify areas of enamel diagenesis, clarify previous notions about enamel preservation in the fields of paleoanthropology and archaeology, and use the data from unaltered enamel regions to reconstruct the seasonal patterns of rainfall at an early hominin site.

This Resource is Part of the Following Collections

• Society for American Archaeology 81st Annual Meeting, Orlando, FL (2016)   •
• New Methods in Zooarchaeology

Keywords

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