Seamless geological map generation using ASTER in the Broken Hill-Curnamona province of Australia

The availability of multiple ASTER image acquisitions enables regional-scale geological mapping, though instrument, irradiance, atmospheric and surface scattering effects can cause problems in generating seamless mosaics of geological information products. These issues, including shortwave infrared (SWIR) crosstalk, were addressed in producing seamless ASTER geological maps over the Curnamona Province, associated with the world class Pb–Zn–Ag Broken Hill deposit. Over 35 ASTER scenes covering an area of approximately 52,000 km2 from 14 different overpass dates were acquired. Maps of Al–OH and Mg–OH/carbonate were generated from ASTER SWIR data as well as a map of quartz content from the thermal infrared (TIR) data. Maps of ferrous iron content were also generated from the SWIR data of individual ASTER scenes. The SWIR bands also enabled qualitative mapping of the Al–OH composition though garnet and feldspar – rich units were not well mapped using the TIR. Field sampling and spectral measurements, together with detailed 1 : 25,000 mapping and large-scale HyMap surveying, constrained the accuracy of the ASTER-derived geological products.