Laboratory experiments confirm that impacts into ice result in a "ring mold shape."
These craters are common in lobate debris aprons and lineated valley fill.
An modification of the formation of ring mold craters being formed by impact into an ice layer was presented at a Planetary Science conference in Texas in 2018.
[4] Although cold and dry at present, Mars undergoes major climate changes in which snow and ice are deposited in certain regions.
It has been known for some time that Mars undergoes many large changes in its tilt or obliquity because its two small moons lack the gravity to stabilize it, as the Moon stabilizes Earth; at times the tilt has even been greater than 80 degrees[5][6] As a result of these climate changes layers of ice are created that when struck by an asteroid can form ring mold craters.