Role of the granular nature of meteoritic projectiles in impact crater morphogenesis

TL;DR

This paper introduces novel volume-diameter aspect ratio diagrams to analyze crater morphogenesis, suggesting that granular impactors influence crater features and challenging traditional uplift models.

Contribution

It presents new scaling laws and a granulometric analysis indicating granular impactors shape crater features and internal structures.

Findings

Crater types can be explained by granular vs. granular collisions.

Central peaks and domes result from dynamic confinement of impactors.

Boulder size distributions support impactor-based formation hypotheses.

Abstract

By means of novel volume-diameter aspect ratio diagrams, we ponder on the current conception of crater morphogenesis analyzing crater data from beam explosions, hypervelocity collisions and drop experiments and comparing them with crater data from three moons (the Moon, Callisto, and Ganymede) and from our own experimental results. The distinctive volume-diameter scaling laws we discovered make us to conclude that simple and complex craters in satellites and planets could have been formed by granular vs. granular collisions and that central peaks and domes in complex craters were formed by a dynamic confinement of part of the impacting projectile, rather than by the uplift of the target terrain. A granulometric analysis of asteroids and central peaks and domes inside complex craters, shows boulder size distributions consistent with our hypothesis that crater internal features are the remnants of granular impactors.