ABSTRACT
This chapter assesses the reliability of the isotopic signature of Lake Turkana carbonates as a measure of past climatic conditions by comparing isotopic records from three cores in the lake with historical records of rainfall on the Ethiopian Plateau. Climate changes that are most consequential to society take place on time scales of decades to centuries. Most rain in East Africa occurs during the passage of the intertropical convergence zone, the ill-defined low pressure zone where the northeast and southeast trades converge and cause convectional rainfall. Freeze coring was used to recover the fluid sediment and to enable the laminations in the sediment to be seen and photographed. When the lake level curve is compared with rainfall in the Ethiopian highlands, it is in these time periods that corresponding rises in lake level are not observed for increased rainfall.
