Arrowhead Craters and Tomahawk Basins: Signatures of Oblique Impacts at Large Scales

Introduction: Crater excavation becomes less efficient with increasing scales and decreasing impact angles (with respect to the horizontal). Possible expressions of such changes in cratering efficiency include increasing amounts of melt [1] or increasing dimension of the central structure relative to the crater diameter [2,3]. Asymmetries in placement and shape of central relief suggest that the central uplift may preserve a signature of the initial trajectory and speed [3,4]. Such a suggestion provides an explanation for differences in central uplift styles (peak vs. peak-ring) for the same crater diameter on a given planetary body. The role of crustal structure [5] is a complementary, not a competing, hypothesis because crustal properties affect the penetration stage. In this study, it is proposed that projectile failure during oblique impacts plays an important role and becomes more evident at large scales due to reduction in crater diameter to projectile diameter, curvature (except at the largest scales), and impact speed.