Both Ancient and Modern

This image of the floor of an old impact crater in Arabia Terra shows evidence of multiple different geological processes, both ancient and modern. The linear ridges and scarps formed eons ago, perhaps as fractures filled with lava or some other dark material that is more resistant to erosion than the surrounding materials in the crater floor. Boulders up to 3 meters in diameter are strewn downslope on both sides of the dark ridge near the center of the picture.