Environmental Change in Namibia During the Last 130,000 Years From Cave Speleothems, Tufas and Fluvial Sediments

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

Southern Africa, and indeed the Southern Hemisphere in general, lacks the paleovegetation and absolute temperature and rainfall data needed for refinement of current biome and General Circulation Model simulations. Namibia presents a unique set of opportunities to develop long records of vegetation, temperature, and rainfall. The abundant caves and speleothems of the country are the key to how this can be achieved, with large waterfall tufas and thick ancient fluvial/aeolian sediment sequences playing supportive roles. The proposed research, which involves scientists from Namibia, Botswana, South Africa, and the U.S.A., will study Holocene environmental change in Namibia during the last 130,000 years from cave speleothems, waterfall tufas, and sequences of ancient fluvial/aeolian sediments. The project will include extensive field sampling, sample dating, staple isotope and other chemical and element measurements, and regression analysis to link ground water fluctuations with climate conditions. The research will compare the newly collected climatic records with archaeological data for Namibia, and for other parts of southern Africa, to evaluate human-environmental relationships during the Holocene. The new data will also be used to compare with records of El Nino frequency to assess its variations during the Holocene. The sparse coverage of terrestrial data in the Southern Hemisphere restricts the kind of detailed data-model comparisons on which the global climate modeling relies. The research will provide new medium- and high-resolution vegetation, temperature, and rainfall data for southern Africa for the last 130,000 years, thus filling a major gap in the terrestrial paleoenvironment record for southern Africa. This would be the longest such record for the subcontinent and the longest records in the world. The data developed will be crucial to accurate global climate modeling, and the comparison with the records of El Nino frequency will help improve our understanding and modeling of El Nino recurrence and intensity in the present.