Aster Imagery And Aeromagnetic Data - Powerful Tools To Aid Reconnaissance Geologic Mapping Of The Sierra San José Mountain Range, Northern Sonora State, Mexico

Aeromagnetic and Advanced Spaceborne Thermal Emission and Reflection Radiometer<br>(ASTER) data are currently being used to assist in geologic mapping of the Sierra San José<br>region in the Sonoran San Pedro River basin. Lithologic contacts have also been mapped using<br>Euler deconvolution of aeromagnetic data. A lithologic classification map consisting of quartzfeldspar,<br>clay-muscovite-sericite, and carbonate was produced using thresholded match filter<br>ASTER data and relative band depth absorption analysis (RBD). A minimum noise transform<br>(MNF) false color composite image was used to map lithologic units. A false color composite<br>image of ASTER bands 1 (blue), 2 (green) and 3 (red) was also used to determine the extent of<br>vegetation and assist in mapping structural features, although most of the structural features<br>could be mapped using high altitude stereo pair imagery. To date, field studies indicate that<br>ASTER data have successfully mapped carbonates, sericite, and muscovite and with lesser<br>success have also helped characterize quartz-rich rocks. In addition, our field studies, along with<br>ASTER and Landsat data, have confirmed lithologic contacts at the surface mapped by Euler<br>deconvolution of the aeromag.