Using C and N stable isotopes in ostrich eggshells to develop paleoenvironmental records for Late Pleistocene East African rock shelter sequences
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.
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Using C and N stable isotopes in ostrich eggshells to develop paleoenvironmental records for Late Pleistocene East African rock shelter sequences. Elizabeth Niespolo, Warren Sharp, Christian Tryon, J. Tyler Faith, Todd Dawson. Presented at The 81st Annual Meeting of the Society for American Archaeology, Vancouver, British Columbia. 2017 ( tDAR id: 429814)
min long: -18.809; min lat: -38.823 ; max long: 53.262; max lat: 38.823 ;
Abstract Id(s): 17106