Ethiopian lakes – Palaeoenvironmental reconstruction in the source region of modern man
The climatic and environmental context in the source region of the emergence of Modern Man is still poorly known. This project is, in strong cooperation with Henry Lamb (University of Aberystwyth), dedicated to the analysis of limnic sediments in Central and Southern Ethiopia in terms of elucidating the climate history of the last 200,000 years, in order to investigate the conditions which led to primary dispersal of Modern Man to Northwest Africa and to the Near East.
The overall project objective is to use data from Ethiopian lake sediments to reconstruct the Late Pleistocene climatic and environmental history of the Horn of Africa at high temporal resolutions. Century to decadal resolution will allow reconstruction of short-term variations in the strength of the East African monsoon, and their links to D/O, NAO and ENSO oscillations. Annual resolution may also be achievable at specific sites over some time intervals, allowing investigation of past seasonality and its influence on the resources available to early human populations. For this purpose, we will recover and investigate long sediment records from selected lakes in the Ethiopian highlands and the Rift Valley. A deep core site will be chosen following phase 1 survey of potential lakes. This will include seismic survey to establish the depth and structure of potential sediment archives, short (<10 m) core recovery and analysis, and limnological survey (including locally-based monitoring) to establish calibration datasets mainly for pollen and ostracods. Tectonic and hydrothermal information will be collected and verified in the field, in order to check for non-climatic influences on lake level and hydrochemistry. Cores will be analysed for sedimentology, pollen, charcoal and ostracods during phase 1 and later for stable isotopes, trace-elements and organic geochemistry, mineralogy, diatoms, grass cuticles and phytoliths. Time-control will be established by a combination of AMS radiocarbon, luminescence, and Ar-Ar analysis of tephras, working towards the construction of a regional tephrochronological framework. Accompanying archaeological surveys in the surroundings of the limnological archives will establish the connection to the human settlement history. The resulting long palaeoenvironmental records promise to provide farreaching insights into the role of climatic and environmental change in the population dynamics, mobility, and cultural development of early modern humans in a key part of Africa, at the source of human dispersal into Europe and Asia.