Re: Circular formations on Mars, their origin(s)
In that picture, here is what probably happened;
First, the smaller impact crater on the right was formed.
Second, the area was flooded with water. This eroded and buried the crater up to its rim. Some of this water soaked into the ground where it froze.
Third, the impact crater on the right was formed. The heat from this impact melted the ground ice causing the ‘splashed’ mud appearance.
When you look at these pictures, remember that everything you see didn’t happen at once. Mars Landscape has been shaped over billions of years. On Mars today, we can see craters of all ages together. Some will be more eroded then others.
You are looking at two dimensional pictures that have a fourth dimension to them- time.