SIMULATED ASTER DATA FOR GEOLOGIC STUDIES

The Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) is a high spatial resolution imaging instrument, scheduled to be launched on NASA's Earth Observing System AM-1 satellite platform in 1998, ASTER acquires data in 14 bands, spanning the visible, near-infrared, short-wavelength infrared, and thermal infrared spectral regions, with spatial resolution varying from 15-90 m, depending on wavelength, In order to evaluate our ability to use ASTER data for geological mapping, we created a simulated 14-band ASTER data set for Cuprite, Nevada, The study site has sparse vegetation and exposes a wide range of unaltered and hydrothermally altered volcanic rocks, The wide range of wavelengths covered by ASTER allowed us to distinguish iron oxide minerals, clay-bearing minerals, sulfate minerals, ammonia minerals, siliceous rocks, and carbonates. Based on interpretation of the ASTER data, and in conjunction with laboratory and field spectral measurements, we produced an alteration map showing the distribution of argillized rocks, opalized rocks with alunite, silicified rocks, and areas dominated by kaolinite and buddingtonite. The map was as accurate as published maps made by traditional field methods, ASTER should be an improvement over existing satellite systems for geologic mapping.