parting shot of the regolith (or is soil?)
is a debris layer of rock and mineral fragments, produced by the physical or mechanical break-up of the parent rock. A soil
, OTOH, is a mixture of rock and mineral particles mixed with organic matter. In my mind, a soil carries with it the implication of chemical weathering in addition to physical weathering. On Mars we have seen the suggestions of chemical weathering in the surface, but no organic component.
So what would the proper term be? It's more than a simple regolith, but not a full-fledged soil.