This image shows a new impact crater that formed between July and September 2018. It's notable because it occurred in the seasonal southern ice cap, and has apparently punched through it, creating a two-toned blast pattern.
The impact hit on the ice layer, and the tones of the blast pattern tell us the sequence. When an impactor hits the ground, there is a tremendous amount of force like an explosion. The larger, lighter-colored blast pattern could be the result of scouring by winds from the impact shockwave.
The darker-colored inner blast pattern is because the impactor penetrated the thin ice layer, excavated the dark sand underneath, and threw it out in all directions on top of the layer. North is up.