Evaluation of the sensitivity of reflectance ratios to mafic minerals in the lunar regolith

The 950/560 nm spectral ratio has been traditionally used as a qualitative indicator or lunar soil maturity because the 950 nm band falls within the major Fe2+ mineral absorption bands near 1 µm characteristic of relatively immature, crystalline surfaces. Since there are several other processes unrelated to maturation that may affect this ratio value, we have evaluated the 950/730 nm ratio as a potentially better measure of the relative 1‐µm band strength. We find that the 950/730 nm ratio appears to be much more sensitive to the 1 µm band depth, but feel that other unknown variables preclude using these single ratios to provide meaningful quantitative results at this time. Because of problems with near‐IR scattering in vidicon detectors used in previous studies, we have measured the scattering properties of our two CCDs and conclude that any scattering is negligible.