Morphologic Mapping of Lunar Impact Basins

Modern high-resolution remote sensing datasets for the Moon provide a detailed view of the lunar surface and its features. This thesis uses visible, compositional, and topographic data to create the most detailed geomorphological maps to date of portions of three lunar impact structures: Orientale Basin, Tsiolkovsky Crater, and Schrödinger Basin, which are three of the best-preserved impact structures on the lunar farside. This thesis discusses the mapping and analysis of seven distinct ejecta facies around Orientale, nine distinct facies in and around Tsiolkovsky, and twelve units of surface materials in the central Schrödinger Basin region. This analysis utilized 100 m/pixel Lunar Reconnaissance Orbiter Wide Angle Camera (LROC-WAC) images, 0.5 m/pixel Narrow Angle Camera (LROC-NAC) images, 10 – 50 cm vertical resolution Lunar Orbiter Laser Altimeter elevation data, Circular Polarization Ratio (CPR) from radar data from the Miniature Radio Frequency (Mini RF) instrument onboard LRO, and FeO abundance maps derived from Clementine spectral data to observe lunar surface morphology and composition. The study regions were then subdivided into distinct facies based on observed surface texture, relative tonality, the expression of topographic structures, and relationship with preexisting topography. The extent of each facies was precisely mapped using the JAVA Mission-planning and Analysis for Remote Sensing (JMARS) mapping program. Patterns in the ejecta material around Orientale and Tsiolkovsky were identified, including a bilateral symmetry to both ejecta blankets and distinct “Forbidden Zones” lacking secondary impact crater chains. The geographic and stratigraphic distribution of different ejecta facies and the interaction of these materials with preexisting topography indicates multistage ejecta emplacement, and specific impact directions and angles for these impacts. The Orientale- forming impact occurred toward the southwest at an angle of ~25°– 45° and the Tsiolkovsky- forming impact occurred toward the southeast at an angle of ~20o – 25o. Additionally, the mapping of the Schrödinger Basin interior enabled the design of a rover traverse path for use in future surface exploration as part of the Canadian Space Agency (CSA) Precursor to Humans And Scientific Rover (PHASR) initiative. This traverse plan includes twenty specific locations where samples could be collected to further our understanding of impact cratering and lunar chronology