INVESTIGATION OF THE CONTROLS ON DUNE COLOR IN THE NAMIB SAND SEA USING MINERAL MAGNETIC ANALYSES

The geological and environmental controls upon the pattern of increasi ng dune redness inland in the Namib Sand Sea are investigated using mi neral magnetic measurements, satellite imagery and dithionite extracta ble iron. Results suggest whole grains or inclusions within grains dom inate the iron oxide assemblage but the sediment colour is more strong ly influenced by a second component which consists of haematite within the grain coatings. The magnetic data suggest that source materials e xert at least a partial control on dune colour in this field setting. Evidence for the influence of other factors (e.g. age and climatic gra dient) is also present. (C) 1997 Elsevier Science B.V.