Texture analysis is playing an increasingly important role in digital image processing techniques to derive physical information about geologic surfaces and processes. The use of traditional reconnaissance mapping tools such as optical remote sensing is severely constrained in tropical regions by almost permanent cloud coverage. The use of radar remote sensing is therefore a preferable means to assess the geology and structural framework of those areas. This paper evaluates the potential use of JERS-1/SAR data to map a geologically complex region such as the Tapajos Mineral Province. We employ variogram textural analysis to automatically identify textural domains that can be correlated to both Archaean-Proterozoic bedrock and Quaternary gold-mineralized placers. The semivariogram classifier proved to be a powerful feature recognition technique that can be successfully applied for regional geologic and mineral exploration studies. 133140