Remote sensing of evaporite mineral zonation in salt flats (salars)

Abstract

Compositional zoning within Salar de Atacama and Salar de Llulliallaco has been mapped from Landsat Thematic Mapper (TM) data. The data were enhanced using decorrelation stretching of TM bands 7, 5 and 4, which were considered to possess the majority of the mineralogical information. The resulting 7, 5,4 (RGB—red, green, blue) colour composites provide excellent discrimination of evaporite mineral zones within the salar.. Our interpretation is supported by fieldwork at the Salar de Atacama and spectral considerations. A strong relationship between the mineralogy of a unit and surface roughness as observed in the field, hence there is potential for imaging radar to provide complementary zonal data. Landsat TM images either on their own, or in conjunction with imaging radar, have shown their potential as an effective method of initial mapping and subsequent change detection of salars.