Using C and N stable isotopes in ostrich eggshells to develop paleoenvironmental records for Late Pleistocene East African rock shelter sequences

Summary

The Middle to Later Stone Age transition in East Africa ~30-60 ka has been hypothesized as a response to increased resource risk due to cooler, drier Late Pleistocene environments with greater short-term variability. Local paleoenvironmental records are needed to test such hypotheses. Ostrich eggshell (OES) fragments are common in African archaeological sequences, are amenable to 14C and U-series dating, and their δ13C and δ15N values are known to correspond to the C isotopes of vegetation and mean annual precipitation, respectively. Here we show that primary stable isotope compositions are preserved in dated OES from GvJm-22 rockshelter at Lukenya Hill, Kenya, and Kisese II, Tanzania for at least 50 ka. Mean δ13C and δ15N values from ~14-3 ka at both sites indicate wetter environments during the African Humid Period, as expected. Prior to 14 ka, mean δ15N values at Lukenya Hill show an overall wetting trend for the past ~50 ka, while at Kisese II, precipitation oscillated, with a dry period during MIS 2. These results suggest distinct paleoenvironmental trends through time at sites separated by only ~300 m elevation, 3° latitude, and 350 km distance, suggesting a more complex mosaic of environmental change in the area than regional/global records resolve.

This Resource is Part of the Following Collections

• Society for American Archaeology 82nd Annual Meeting, Vancouver, BC (2017)

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Record Identifiers

Abstract Id(s): 17106