Mg-Spinel Distribution in South Pole-Aitken (SPA) Basin: Spatial Distribution, Geologic Context and Spectral Characterization

Abstract

The spatial distribution of Mg-spinel lithology at South Pole-Aitken (SPA) basin is revealed by systematic mineralogical survey along the basin rings. We report Ingenii-Thomson region as a Mg-spinel anomaly, having the largest number of exposures based on newly identified and previously reported occurrences on the Moon. The timing of Mg-spinel formation is constrained by using SPA impact as a key geological time marker. Post-SPA origin of this lithology is favored in this region due to the general lack of pervasive Mg-spinel occurrences along basin rings, being the deepest exposures of the pre-SPA crust. Our detailed mineralogical analyses also highlight several detections of Mg-spinel lithology exhibiting weak 1,000 nm absorption band, emphasizing the need for a detailed analysis of such locations. Collectively, these salient findings have important implications for understanding the compositional diversity of Mg-spinel lithology, refinement of the formation models and determining the role of Mg-spinel lithology in the lunar crustal evolution.