The Makgadikgadi basin, a dynamic hydrological input and aeolian output system. Frank D. Eckardt a,* , Robert G. Bryant b, Warren W. Wood c, Kevin White d, Baruch Spiro e, Graham McCulloch f a Environmental and Geographical Sciences, U niversity of Cape T own, P Bag X3, Rondebosch, 7701, South Africa b Department of Geography, Uni versity of Sheffiel d, Dept. of Geography, Wi nter Street, Sheffiel d, S10 2TN, U K c Department of Geol ogical Sciences, Michigan State Uni versity, East Lansi ng, Michigan 48824, USA d Department of Geography, The Uni versity of R eading, Whiteknights, R eading, UK e Department of Miner alogy, The Natural Histor y Museum, Cromwell Road, London SW7 5BD, UK f Department of Z ool ogy, Uni versity of Dublin, Trinity College, Dublin 2, Irel and * Correspondi ng author:
[email protected] This study focuses on modern day processes surrounding the Makgadikgadi pan basin system in NE Botswana. We present results on the chemistry and dynamics of fluvial surface water inputs, examine the nature and chemistry of various surface and subsurface evaporation products, provide data on the nature and chemistry of aeolian outputs and demonstrate the impact of aerosol deposition in the downwind sector of the pans. During the wet season surface water enters the saline pans and precipitates mostly calcite and halite, as well as dolomite and traces of other salts associated with the desiccation of the lake. The hypersaline subsurface brine (up to TDS 190,000 mg/l) is homogenous with minor variations due to pumping by BotAsh mine (Botswana Ash (Pty) Ltd), which extracts 2400 m 3 of brine/h from a depth of 38m.