Characterization of melt and ejecta deposits of Kepler crater from remote sensing data

Abstract

AbstractWe used Moon Mineralogy Mapper (M3), Arecibo and Mini‐RF radar, and Diviner radiometer data with Lunar Reconnaissance Orbiter (LRO) Camera and Kaguya Terrain Camera images to characterize the target, ejecta, and impact melt‐rich lithologies in and around lunar central peak crater Kepler. M3 data indicate the impact melt rocks of crater floor to be high‐Ca pyroxene dominated, distinct from the low‐Ca pyroxene‐dominated crater wall. The central uplift is high‐Ca pyroxene dominated, and has higher albedo. These observations are consistent with thin mare basalts underlain by noritic Imbrium ejecta, underlain by gabbroic crustal material. M3 data reveal an enigmatic, splash‐like feature of melt‐rich material on the southeastern (uprange) crater wall and flank. M3 data also highlight halos around Kepler. In detail the halos are slightly variable, but in broad terms they define a consistent feature, offset to the inferred downrange direction, and interpreted to reflect the distribution of glass‐bearing impact breccia. The radar data sets show most of the proximal ejecta to be radar‐bright. However, Diviner rock abundance data do not indicate the presence of blocks on the surface nor can they be seen using LRO Narrow Angle Camera images. Thus, the blocks giving rise to the enhanced radar signal are buried. Beyond the radar‐bright zone, a subtle radar‐dark halo emerges, coincident with a region of very low rock abundance in Diviner data. This multidisciplinary approach provides a robust analysis of the main characteristics of a lunar complex crater and reveals previously unidentified features related to the distribution of impact melt.