"Don't get me wrong, Mars is definately the home of some very non-earthlike geology, not to mention electrostatic sedimentary and chemical effects, but I think this one is more mundane than that. Keep looking! :)"

Yeah, could be more mundane, agreed. Still, never hurts to toss out the alternate theories... On the off chance they're right. Though the triboelectric effect seemed to create a lot of spiny formations, I didn't see a ton of large flat ridged structures in the triboelectric bit. Though I'm wondering if similar processes might form large flat ridged structures. Or, alrternately if similar processes to triboelectric charging could create and somwhow cement the spiny structures closely enough, that the weathering of the spines would reduce them to nubs, and just leave the agglomerated ridges (sans large spikes?).

Dunno. Interesting, but inconclusive. If nothing else, interesting physics (even if unrelated, which it could be).