HYPERSPECTRAL-BASED MINERAL IDENTIFICATION FOR GEOLOGIC MAPPING APPLICATIONS

Investigations are being conducted into the usefulness of airborne hyperspectral data for detailed geologic mapping applications. Emphasis is placed on evaluation of hyperspectral data as an aid to geologic mapping as normally done by ground-based reconnaissance on a large-scale map base.

Hyperspectral data provide a means of identifying surface mineralogy, and are an aid to lithologic mapping. The data being analyzed were collected by the HYDICE (visible-shortwave infrared) and SEBASS (longwave infrared) airborne imaging spectrometers. Results indicate the ability to produce general mineralogic/lithologic maps at scales better than 1:24,000 using 1-meter resolution data. Also, a more thorough mapping was achieved because of the increased compositional information gained by using both the shortwave and longwave spectral information.

In addition, the 1m data were spatially degraded to 5, 10, 20, and 30 meters to compare the effects of lower spatial resolution on mineral identification and resultant mapping and to evaluate how spatial resolution translates into map scale. In general, the results indicate that while spatial detail is rapidly lost as resolution degrades, spectral detail tends to be retained, which allows for accurate moderate-scale mapping.