re: Meridiani soil -- airbag imprints vs wheel tracks, huh?
I address this here. But in a nutshell I think it is that the reflection is due to compacting of the surface granules. I believe the airbag bounces exerted considerably more force upon the surface than do the regular tire tracks.
I also think that a secondary factor regarding reflectivity is that this reflectivity is aided by the smoothness of the impacting surface, creating a smoother and, subsequently, more reflective surface. The airbags are considerably smoother than the tires.
SDAI-Tech1