CONTROLS ON DUNE COLOR IN THE NAMIB SAND SEA - PRELIMINARY-RESULTS

The red colouration observed in many sand seas is a consequence of fin e grained haematite and clay coatings surrounding quartz grains and a number of hypotheses have been proposed to account for this. The marke d increase in dune redness with increasing distance inland in the nort hern area of the Namib sand sea is investigated using satellite imager y and mineral magnetic measurements. These results suggest that source materials exert at least a partial control on dune colour in this fie ld setting, but that evidence for the influence of other factors (e.g. climatic gradient and/or abrasion of coating during transport) is als o present.