Between the lines it seems to me that they think that there is just one grand sedimentary sequence on Mars. I dont see it that way. I see a formerly tectonically active planet that will contain many episodic sequences and cyclic sedimentation, just as on Earth.

dark eolian sediments to the rim in arm's reach

I think there is evidence for an erosional unconformity here. The very wavy sediments in the middle are overlain by a dark layer without any outcrops. This darlk layer is much flatter on top, so I think the top of the light wavy layer is a former erosion surface with hills. The current surface is also very flat and erosional. The layers in this area seem confusing; I suspect some of them have slumped into the crater from higher up, and are seen more than once in a given transect.
An Unconformist