Geologic mapping using thermal images

In the past, remote sensing from aircraft and satellite for geologic mapping concentrated on the visible and reflective infrared parts of the spectrum, because of the availability of Landsat and aircraft multispectral scanners operating in this spectral range. With the launch of the Heat Capacity Mapping Mission (HCMM) satellite, regional thermal image data also became available. We have examined the HCMM data for geologic information over two desert areas in southern California, the Trona area and the Pisgah area. Three techniques were used for displaying and combining thermal data and visible and near infrared, including color additive composites, principal components, and calculation of thermal inertia images. Use of the color additive composite image was simplest and allowed for simultaneous display of both thermal and reflectance properties. Thermal data were found to provide additional geologic information, unavailable from Landsat data or from aircraft visible and near-infrared data alone. The addition of these data relating to thermal properties allowed separation of rock types with differing thermal properties but with similar reflectance characteristics.