PLIO-PLEISTOCENE PALEOVEGETATION RECONSTRUCTION USING BULK PALEOSOL ORGANIC MATTER FROM THE BARINGO BASIN, KENYA

During the Pliocene Epoch, atmospheric CO₂ levels were similar to modern and near-future conditions. Understanding the response of floral communities to increasing CO₂ is a top priority in paleoenvironmental research and can provide valuable information on possible biome changes under anthropogenic climate change. The Chemeron Formation from the Baringo Basin in central Kenya contains records of terrestrial and lacustrine strata across the Pliocene through Pleistocene Epochs. In this study, we analyzed paleosols from the Baringo Basin, which include both outcrop and the BTB-13 drill core, to reconstruct paleovegetation using bulk organic carbon isotope ratios (δ¹³C). Samples were oven-dried and then ground to a fine powder using a mortar and pestle. The paleosol samples were then decarbonated in silver capsules using 1M HCl on a hot plate at 50℃. All samples were subsequently dried and wrapped in tin capsules. They will be analyzed for their δ¹³C value using an elemental analyzer coupled to an isotope ratio mass spectrometer (EA-IRMS). Results from these analyses will be used to compare the relative abundance of C3 and C4 vegetation across the Pliocene to early Pleistocene. These records will be contextualized with paleoprecipitation trends reconstructed from the same paleosols using bulk geochemical proxies. Our ultimate goal is to better understand interactions between plant communities, local climate conditions, and long-term CO₂ change in one location through time.