THE INFLUENCE OF WEATHERING AND LICHEN COVER ON THE REFLECTANCE SPECTRA OF GRANITIC-ROCKS

Results are presented from a series of laboratory experiments that examined the effect of surface weathering and lichen cover on the spectral reflectance of granitic rocks over visible and infrared wavelengths. The effect of weathering on the rock reflectance varied with rock type. However, all the lichen-affected spectra, which included four different species, exhibited the same five diagnostic absorption features in the high resolution spectra. More general changes in curve characteristics were also evident in the lichen-affected spectra. The diagnostic absorption. features were evident in spectra from samples with less than 50% lichen cover. Certain mineralogic features remained evident in the spectra despite the surface lichen cover.