Lunar Impact Ejecta Degradation and Maturation Signatures

Science Goals: Spectral measures of maturity in the visible portion of the electromagnetic spectrum modestly correlate with magnetic indices of lunar soil samples enabling an evaluation of lunar surface maturation processes. Newly acquired data of the lunar surface from multispectral instruments (e.g., the Moon Mineralogy Mapper and The Kaguya MI), the Diviner lunar radiometer, LROC WAC, and the Mini-RF radar now allow us to explore maturity relationships at a variety of wavelength regions relative to Clementine color data. Our preliminary investigations suggest that the maturity of features can be identified at a variety of wavelengths, though the features may manifest differently depending on the wavelength region examined. Examination of three craters of differing ages (classified as "young", "intermediate" and "old") suggest that age effects are seen in all wavelengths. However, no detailed study integrating these multiple perspectives across the lunar surface has yet been performed to better understand these potential relationships. Here, we propose an integrated study of crater ejecta blankets to probe maturation processes to better understand how crater ejecta degrade in various terrains across the lunar surface as seen in remote sensing data spanning from the UV to microwave wavelengths.

Proposed Methodology: We will investigate the ejecta blankets of young lunar craters using a variety of data sets, at a variety of wavelengths, to better understand their emplacement, maturity, and degradation history. Specifically, we will analyze data from the spectrometer on board Kaguya, LRO's Diviner, the LROC WAC, LRO-LAMP, and the Mini- RF instrument to examine maturity of lunar materials, specifically ejecta blankets of young craters, and assign (relative) ages to these craters based on the calculated maturity with each data set. We will also leverage Clementine color data to generate OMAT maps to enable comparisons with a standard maturity index. This will be done in 4 main tasks: 1) Examine radar scattering characteristics of young crater ejecta across the lunar surface, 2) Examine these same craters in optical, thermal and UV-VIS data sets to identify any maturity effects across wavelengths, 3) Integrate relative ages from different data sets and compare with OMAT; 4) Examine specific correlations between indices identified in various data sets.