Piston cores from northern Lake Turkana in Kenya contain strong cyclic records of carbonate abundance and lamination thickness. One of these cores has been radiocarbon dated and shows several strong cycles (significant at the 95% confidence interval) in the range of decades to centuries. The proposed research on cores from this lake has two primary objectives: first, to determine the climatic and limnological significance of the cycles and second, to determine the phase relationships of the various cycles relative to one another and to the present day. Field work will entail deployment of a sediment trap, and collection of freeze and piston cores, and filtration of water samples. The significance of this research is that Lake Turkana sediments provide a unique opportunity to: (1) gauge the cyclic behavior of climate in sub-Saharan east Africa for a period of 4000 years with unusually high temporal resolution, and (2) assess man's impact on climate in this region of Africa with the perspective of 4000 years of historical record.
