| Imaging spectrometry, a new remote sensing method, can be used as a geologic tool to analyze and map sedimentary lithofacies. Imaging spectrometry seeks to combine the quantitative methods of reflectance spectroscopy with the synoptic viewpoint of imaging remote sensing. The high spectral resolution of imaging spectrometry data permits compositional analyses on a pixel-by-pixel basis. The spatial context of the data allows for the mapping of these spectrally derived results. Geophysical inversion theory provides the proper framework for analysis of these data. The forward model, linking observable physical parameters to the geological information of interest, is complicated. The spectral reflectance properties of the surface are controlled by its compositional and physical properties. The observed data, spectral radiance, are not only a function of the surface reflectance but are also influenced by topographic, atmospheric and instrument effects. Using geophysical inversion methods, this complex forward model can be inverted, deriving quantitative results and estimates of their uncertainty. Specific facies analyses illustrate the application of these concepts to three different facies studies of sedimentary formations exposed in the Rattlesnake Hills area of central Wyoming. The Frontier, Chugwater and Goose Egg Formations provide example facies studies. |
