Notice the dune-like formations on the lighter, lower elevation plain that are missing from the darker, higher elevation? Wind is probably blowing all the dust and sand off the higher elevation and it collects on the lower plain, causing the lighter color.
Spice blows.........................obviously..............
Looks like that to me too. Those are definitely dune ripples, even in the bottom of the craters.
It’s there in the darker area too, you just have to look close. Look in the left section toward the top of the dark area, where two medium sized craters overlap. Just below those and to the right you can see it, and in the bottom of several craters, then once you see what to loo for, it becomes more visible in other areas.
Also, I notice some craters have no dune effect. Newer ones not old enough yet to show this dune effect?
But wait...I may be wrong here but I thought Mars didn’t have an atmosphere, so where does the wind come from? This definitely looks like the work of either wind or water, and water has been long gone for eons, or am I wrong and Mars does have an atmosphere of some sort?