Mamta Chauhan

and 2 more

Central peaks of lunar complex craters of Copernican period provide best examples to study morphologies of impact melts and exposed subsurface as they are better preserved and less affected by the space weathering. Crater Tycho, present towards SW, nearside of the Moon is one such example of young and fresh complex crater. Present study is high-resolution mineralogical investigation coupled with morphological study of central peaks and floor of crater Tycho and other contemporary craters to understand the nature of occurrence and distribution of compositionally distinct lithologies identified near their central peaks that differ in colour and specific appearance. A detailed high-resolution analysis suggests that the clastic exposures associated with the melts have a mafic composition that have been observed at similar other contemporary craters. They represent the fragmental polymict breccia clasts and their stratigraphic relation with the melts alongwith with their mineralogy suggests them to be representative of subsurface anorthositic gabbro/noritic body. Their occurrence and association with structural features, such as breccias dikes and cooling cracks suggest their formation at different stages of cratering and associated crustal modification. The formation mechanism of the polymict breccia clasts causing lithological variability has been discussed. We also report here the occurrence of rejuvenated dykes peculiar to Tycho setting that are distinct from the fractures in the immediate viscinity. Their unique nature suggests different emplacement mechanism associated with dynamic cratering process till not reported at any young complex crater on the Moon.