Morphologic mapping and interpretation of ejecta deposits from Tsiolkovskiy crater

Abstract

AbstractHigh‐resolution images and elevation data sets from the Lunar Reconnaissance Orbiter along with spectral data from the Clementine mission are used to identify and map in detail the well‐preserved Late Imbrian Tsiolkovskiy crater situated on the far side of the Moon. This study identifies five distinct morphologic units associated with Tsiolkovskiy crater and the surrounding ejecta blanket. Analysis of the spatial and stratigraphic relationships of each of the ejecta units shows an asymmetrical distribution of the overall ejecta blanket, as well as a consistent overprinting of ballistic ejecta by ponds and flows of impact melt‐bearing material. This study shows that the asymmetric distribution of the ejecta blanket, including a distinct up‐range “forbidden zone,” is related to the impact direction and angle for the impactor that formed Tsiolkovskiy crater. The consistent presence of melt‐bearing ponds and flows overlying the ballistic ejecta deposits indicates that two separate ejecta emplacement events occurred. We interpret this as an initial phase of ballistic ejecta emplacement during the excavation stage, followed by a second phase of melt‐bearing ejecta emplacement. The second phase begins during the end of the excavation stage and continues throughout and beyond the modification stage of crater formation.