Characterizing Volcanic and Impact Materials in Lunar Craters


Impact craters on the Moon are typically infilled by either impact or volcanic melt, but outside of a few previously known characteristics, identification can be complicated. Morphological and compositional characteristics are the best options for definitive differentiation between volcanic and impact in impact craters. In this paper the history of lunar morphological research is reviewed and eight craters >60km in diameter are mapped to create a comprehensive list of features of note using the maps available through JMARS. Over the past 50 years, interest in lunar morphology has been primarily impacted by the technology available. Without high definition views of the lunar surface, studies on the Moon’s craters focused on size and volume instead of internal components. As technology improved, the study of lunar craters expanded. This thesis shows that many features of note in impact melt-filled impact craters exist primarily on the crater floor. That floor has been obscured in volcanically-filled impact craters. Impact melt-filled impact craters also maintain the same albedo and composition as the surrounding terrain, while volcanically-filled impact craters are of a darker albedo and mafic composition. The existence of terraced rims is affected by age rather than interior fill composition, unless the interior melt has obscured any terraces. Crater rims slump with age and therefore cannot indicate alone the type of melt inside the crater.



Planetary Science, Astronomy, Moon, Crater morphology