Quantitative Mineralogy Using Radiative Transfer Modeling

Near-IR spectra of lunar materials are strongly affected by both mineral abundance and mineral chemistry. Using a radiative transfer mixing model, we have developed methods to invert reflectance spectra and produce mineral abundances and Mg-number (ratio of Mg to the sum of Mg+Fe) from Clementine data, and from ground-based spectra of the Moon. Our approach has been to use a radiative transfer model that computes lunar spectra from first principles, then use various approaches to invert this model. Among the challenges of this approach is the quality of the data for optical properties of minerals, especially pyroxenes, the scarcity and quality of data to validate the approach, and choice of simplifying assumptions. We present our current status of deriving mineral abundance and chemistry from lunar spectra.