Can't tell if the white areas are recent coating of sulfate dust or if the white is bedrock with dark material as the coating. Seems like alot of float on the surface. I can't wait to see it in context. But indeed, if the polygons are found in the lower units I have to re-examine (or abandon) my earlier thoughts concerning the timing of fracturing. Do we have really good orbital pictures to discern the geometry of the regional fracture pattern? I still wonder if they are related.

Last month's GSA Today had an article titled Dilational fault slip and pit formation on Mars (abstract). The authors make a fairly convincing case for active dilational normal faulting. Their postulation as to how the surface of Mars is expanding? Expansion associated with the freezing of water saturated sediments. Hmmmm. The article deserves a longer review, maybe later.

Here's another example of the different rock types:

Look at this bedding! Oh I can't wait for compositions on this stuff! Looks sulfate rich, but that might be coating. Would a greater iron content trick the TES into a mafic call on this stuff? Some polygonal fractures here too, but some orthagonal aspects as well.

I have to keep reminding myself that this surface is likely not horizontal.

Thanks for the heads up on the pancams, Nick. Lots to see there.