Use of Landsat thematic Mapper imagery as mineral prospecting tool in the tin province of Goias, Brazil

Abstract

The Tin Province of Goias, in central Brazil, includes several granitoids with greisenized‐albitized facies, which occupy the apical parts of the massifs. Stanniferous mineralizations (cassiterite) frequently occur associated with these metasomatkally altered facies. Areas of altered rocks bear open grasslands in contrast to the savanna‐type vegetation cover composed of small trees, shrubs and herbaceous plants occurring everywhere over the granitoids. Landsat Thematic Mapper ratio images (TM4/TM3) of the rainy season were used to delineate these target areas within the granitoids. Follow‐up field checking confirmed the occurrence of metasomatic rocks with cassiterite in most of the delineated areas. Thus, future prospecting work for primary tin deposits in the granitoids of the region can be largely facilitated by the use of this procedure.