Early in the life of the Solar System, things were a lot more violent than they are today. Rocks were flying everywhere, willy-nilly, smacking into the newly formed planets, pocking them with craters ...
Cassini SAR (synthetic aperture radar) images of Titan's impact craters. Arrows indicate potential forms of crater modification processes, including: dunes and sands (purple), channels (blue), and ...
a large asteroid impact could relatively easily punch through the crust and into the mantle below, allowing lava to flood upward and pool in the resulting crater, forming, in this case ...