[doodad]

Mars is generally believed to not have experienced earth-like plate tectonics

I hadn't heard that(don't follow the astro stuff as much as terrestrial), but volcanism certainly points to some kind of fluid transfer from the interior of the planet to the surface and the deformation at the area. I guess we will find out.

[John H K]

There are some really large-scale bulges in the volcanic areas (causing faulting, etc.) but no evidence of plates sliding around.