PALEOLIMNOLOGICAL CHANGES ACROSS THE LAST GLACIAL MAXIMUM AT LAKE NAKURU, KENYA

The complex topography of the East African Rift System (EARS) due to active volcanism and tectonics results in variable rainfall which creates small rift basins that can amplify climate signals. Such “amplifier lakes” are vital to understand how larger scale global climate changes impact smaller scale environments, particularly on a continent that is vulnerable to natural disasters resulting from anthropogenic climate change. During the Last Glacial Maximum (LGM; 25-21 ka), rainfall dynamics of the EARS were altered as the global climate system shifted to an interglacial period leading into the Holocene. This research explores how Lake Nakuru, currently a shallow, highly alkaline lake located in central Kenya, changed across the LGM in response to global changes in climate. Samples were retrieved at 5-cm resolution from the upper eleven meters of two duplicate, 17-meter drill cores taken by the Lake Naivasha Coring Project in 2004. The chronology of the cores is based on a newly developed age model based on 11 AMS ¹⁴C ages measured on charcoal and two ⁴⁰Ar/³⁹Ar ages from separate tephra layers. These preliminary results use grain size analysis, X-Ray Fluorescence (XRF) data, and diatom identification to explore high resolution lake level variability of Lake Nakuru. The aim of this project is to reconstruct the paleolimnology of Lake Nakuru across the LGM to understand how global changes in climate impacted Nakuru’s hydrology and paleoproductivity, increasing understanding of how large-scale systems impact small-scale systems most vulnerable to current climate change.