Quantitative Validation of Formation Mechanism of Lunar Floor Fractured Craters

Lunar floor fractured craters are a special class of craters modified by post impact mechanisms resulting from geological activities. Two theories of origin of FFC's have been hypothesized: magmatic intrusion and viscous relaxation. We attempt to validate the hypothesis drawn in favor of magmatic intrusion as formation mechanism. The approach was to extract and analyze those properties of FFC's which would be affected by crater formation mechanism so as to predict the mechanism they favor. The origin of FFCs is investigated by observing implications of morphology and morphometry on formation mechanism andby study of aerial distribution. This study focuses on analysis of morphological features namely diameter, depth, rim height, crater symmetry and presence and absence of interior features like moats. The key features/parameters were determined by in-house developed software and analyzed for 83 floor-fractured craters belonging to different classes. It was concluded that FFCs possess lower depth-to-diameter ratio as compared to predict through empirical relationship documented in literature. At the same time, FFCs possess intact rim heights, depicts moats in the floors and do not show any axis-symmetric deformation. All this provide strong evidence against probability of formation of crater by viscous relaxation hence supporting magmatic intrusion as origin of floor fractured craters.