Stable isotope analyses of authigenic calcite from Lake Turkana, Kenya: High resolution paleoclimatic implications for the past 5000 years

Climate variations on time scales of years, decades or centuries can have significant impacts on food, water and energy resources. Carbon and oxygen isotopes in lacustrine basins have been used for a number of decades as a proxy for past climate change. Authigenic calcite from Lake Turkana, a closed basin in northern Kenya, is analyzed in the present study for carbon and oxygen isotopes. The stable isotope record in short gravity cores is compared with the relatively short meteorological record. The paleoclimatic record for the past 5500 years is obtained from longer piston cores. Although it is clear from this study that the isotope record in authigenic calcite at Lake Turkana is not a one-to-one representation of the rainfall record, the long-term oxygen isotope record does reflect actual lake level fluctuations and can be used as a proxy for lake level change beyond the historical record.