Mapping the Iron Oxide Content of Dune Sands, Namib Sand Sea, Namibia, Using Landsat Thematic Mapper Data

A linear mixture model was applied to Landsat Thematic Mapper data to map iron-oxide content over the northern part of the Namib Sand Sea, Namibia. Field samples were collected to calibrate the remotely sensed iron oxide proportions to dithionite extractable Fe in mg g(-1), the in situ proportions correlating strongly with the remotely sensed estimates (r=0.91). The results reveal a region of high Fe-oxide concentration in the east, an area of low Fe-oxide concentration in the west, separated by a mixing zone. We interpret this to indicate that there is more than one sand source contributing to the sand sea. (C) Elsevier Science Inc., 1997.