Scooby Doo could be soil that has been cemented together by water or acid rain.
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Joy Crisp video Joy Crisp audio -- |
The closest rock that I've seen that comes to that, and I'm not sure that it's a rock, would be Scooby Doo. Scooby Doo could very well be soil that has been cemented together, perhaps either by water and things in the water that calcificated out or acid rain (which we could've had on Mars long ago) and somehow glued the grains together so much so that it turned it into rock. On Earth we call this hard pan. But we're not sure-- the dividing line between a hard soil and a rock is a difficult one to make. We've spun the wheels of the rover around on Scooby Doo and we saw no effect and no scratch marks and some people thought that this was then proof that it was a rock. But unfortunately, we have counter evidence that in the rock yard here at JPL we went out to some hard soil and didn't make a mark there either. So we're left not knowing for sure if Scooby Doo is a rock or not, but it very well could be what we would then call a sedimentary rock.
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Matt Golombek audio |
Now from that, we decided to go over to Scooby Doo, which is a whitish patch. It's a low kind of indurated-cemented rock in a clockwise sense, and we put the APXS down against it. We managed to do that and get an APXS measurement of Scooby Doo, and then we tried to disturb Scooby Doo with the wheels. We did a roll-bar pull test and we rotated wheels on it. We couldn't do anything to it. It's well-cemented together, so it's like a cemented soil of some sort because its chemical composition looks like a regular soil.
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Ron Greeley video Ron Greeley audio -- |
Scooby Doo is an interesting rock because first it has a very high reflectivity, it has a white appearance and it's sort of flat down on the ground. Now, we're not really sure if it's a rock or if it's compacted soil. The compositional measurements have not been refined yet so we're not quite sure what it's made of. One of the exciting possibilities is that it could be a sedimentary rock of some kind.
