PALEOENVIRONMENTAL AND PALEOCLIMATIC CHANGES IN TROPICAL EAST AFRICA SINCE THE LGM, NEW RECORD FROM THE CHERANGANI HILLS, KENYA

The climatic changes in the late Pleistocene to the Holocene period have been significantly associated to the Late Glacial Maximum (LGM) and Africa Humid Period (AHP) between 15 to 5 Ka according to previous published works of the East African region. This research focuses on East Africa in the past to provide insights into the controls and timings of climatic variations from the past. The significant disparity of timings of events in the continent of Africa remains due to limited geographical coverage, low-resolution proxy and the tedious work involved in obtaining past high resolution data. Furthermore, these constraints make it difficult to discern the difference between paleoenvironments and paleoclimates that are as a result of human disturbance and those that result from natural climatic changes. This study presents high resolution sedimentological data valuable for effective paleoenvironmental and paleoclimatic reconstruction up based on a strong age model developed by ¹⁴C dating, pollen, fungal spores and charcoal analysis at 1 cm intervals along cores collected from three different sites in Kenya. This is supported by LOI and XRF data.

Preliminary results from Loss on Ignition (LOI) and XRF data tied to the strong age-model developed for this study are indicative of probable cycles of desiccation and humid periods evident, with the former at around 5300 years BP and the latter 17500 and 19600 years BP. These coincide with the times of occurrence of major climatic events in other published studies which resulted in fluctuating thus humid and desiccation conditions prevailing in these periods. To complement other studies focusing on pollen and fungal spore assemblages to improve understanding of past climates and environments of East Africa, this data is enhanced by the quantitative palynological analysis which show the signatures of human interference in the record as early 2500 years BP. Therefore, this study improves spatial-temporal understanding of climate variability of in East Africa responsible for vegetation change and habitability of the environment. The study also allows for the description of climate variability and vegetation patterns induced by humans in Africa where it is believed that anatomically mankind has interacted with the environment from approximately 200 ka Years ago, hence, a clear distinction.