Orbital Characterization of the Composition and Distribution of Spinels Across the Crisium Region: Insight From Luna 20 Samples

Spinels represent a small fraction of lunar surface materials but provide important insights into the petrological evolution of the lunar crust and mantle. Previous remote sensing analyses of highlands spinel-bearing lithologies have focused on pure Mg-Al spinels, which are rare in the lunar sample collection. Using Moon Mineralogy Mapper data, we develop and test an approach for detecting spectral signatures of spinel across a wider range of Mg, Al, Fe, Cr, Ti-bearing compositions than have been addressed in previous studies, including within mafic-bearing assemblages. This approach is validated through integration with laboratory-measured spinel spectra and petrographic observations of samples returned by the Luna 20 mission from the Hilly and Furrowed Terrain surrounding the Crisium Basin. Applying this approach to data from the Crisium region, small abundances of spinel (More