Re: Not a landslide, IMHO
You are probably right. This deposit was probably a long process.
There are some outcroppings near the rim of the crater. It looks a though the small mountain was created after the meteor, but I don’t see how this could be the case. The crater had to come after the mountain was created. The impactor must have blasted away part of that small mountain and over time, debris has slid down to fill half the crater.
I just love Geology.