re: Here's some interesting interpretation
from Terragen renderings
Note the view is approximately the same as your THEMIS oblique view. And we see "lakes" within craters and other lowlands. But none (except in a crater) where the THEMIS shows light-colored warmer terrain. However, in the Terragen rendering it appears that the lighter/warmer terrain is in fact lower than the region of the landing ellipse. The landing ellipse appears to be on a slight rise.
The overhead view here may make the elevation differences clearer. The upper left quadrant of the images appears to correspond with the lighter/warmer areas of the THEMIS image.
This image may help sort out some of the elevations as well.
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