[X] My Assistant

[dvandorn]

I was just looking at the large-scale Opportunity route map done by OSU Mapping/GIS Laboratory, and my impression that the etched terrain overlies what was once heavily cratered terrain was highly reinforced. Here is the original OSU/GIS route map:



I see what looks like the highly eroded remnants of rather heavily cratered terrain all throughout the etched terrain to the west of Oppy's route. Here is a version of that same image that I have somewhat roughly annotated with red circles that approximate many of the ancient craters I think I can see:



Sorry about the crudity of my drawings -- all I have available is MS Paint to do this kind of thing.

Anyway, this gives me the impression that the area was once heavily cratered. The question is, are the ancient craters features that predated the deposition of the evaporite, or have they just eroded down because they were made in the very soft evaporite layer? I'd think that these craters would be so large that they would easily penetrate well beneath the evaporite layer -- so my bet would be that the ancient craters were worn down by water, after which the evaporite was laid down on top of them. That would explain why they are so subdued.

Since we have actually visited the rim of one of these craters (Erebus), it seems to me we ought to be able to make some kind of judgment as to whether these craters were made before or after the deposition of the evaporite.

-the other Doug

[diane]

"Adjectived" has a more fingernails-on-the-chalkboard grating quality than "adjectivized". I'll stick with it.

As for "teh" well, live and learn!