http://marsrovers.jpl.nasa.gov/gallery/all...4P1131L0M1.HTML

I'm betting those dark crumbling rocks are the remnants of ejecta hurled from a crater (Victoria perhaps) made long after the lakebed dried up.

I think so. The outcrop stone and dark stone cannot be mixed. Let the IDD zoom on it in order to confirm.

Rodolfo

Im not so certain about that, Erberus do show dark patches too at the rim suggesting the dark material was there when the crater was created. And its one very old and eroded crater. So I keep an open mind about where these darker rocks/material originated.

There is no telling about the dark angular fragments at this point. We've been seeing them in increasing numbers the further south we drive and I think I'm starting to see larger pieces on the evaporite bedrock. We'll see what it is soon enough.

We need a marker horizon!

--Bill

Finally, an MI. http://marsrovers.jpl.nasa.gov/gallery/all...4P2936M2M1.HTML

But it's hard to say much about it, other than it's fine grained and fractured. The ubiquitous Martian basalt?

Maybe these dark rocks are fragments of what lies beneath the evaporite layer? Erebus is the largest impact structure we've come close to, we ought to be traveling right now over the degraded remains of its ejecta blanket. The soft mostly-salt evaporite rocks that probably made up most of the ejecta blanket have weathered down to a flat plain, but if small, very shocked pieces of whatever underlied the evaporite layer were mixed in with the evaporite in the ejecta blanket, I would expect to see such chunks lying out on the ground, the softer evaporite having eroded away around it.

-the other Doug

In his latest update, Steve Squyres says they have 2 principal theories - ejecta or meteors.

http://marsrovers.jpl.nasa.gov/gallery/all...D4P2957M2M1.JPG

I don't think the MI is going to make much out of this and the clump of rocks is likely too small to get an accurate reading on with the other instruments. Maybe they should 'stomp' on them with the rover and try to shatter some or at least scrape them off.