[X] My Assistant

[Kye Goodwin]

I have been reading the response to the reponse to impact-surge linked by Dr Burt in post 170. The MER team objects to the impact-spherule explanation because " The spherules are dispersed nearly uniformly across all strata." I agree that is a valid criticism. It is very much like Dr. Burt's criticism of the MER team's hypothesis, that spherule distributions are not consistent with any conceivable ground-water movement regime that should have controled the development of concretions. I agree strongly with this point of Dr. Burt's as well. Neither theory does a good job of explaining the distribution of the spherules. Also, neither theory does a good job of explaining why the spherules do not apparently disturb the bedding.

There may be a solution in a possibilty that I now raise with some trepidation. I think that there is a chance that the spherules are superficial, and not an integral part of the Meridiani strata at all. This probably sounds crazy to many readers, but before rejecting it outright remember that science is at kind of an impasse on this and could use a new idea. If the spherules are superficial this would explain a number of puzzling observations.

The layering at Homeplate and Meridiani is most simply explained by impact-surge. It is elegantly and inescapably explained by impact-surge. The impact-surge authors have also tried to explain the Meridiani spherules as part an impact event. If doubts are raised that the spherules are integral to the deposit, this would not in any way be inconsistent with the impact-surge origin of the layered structure. On the contrary, an objection to impact surge would be removed.

I intend to start another thread under Opportunity to discuss this question. The first posting should be mine and should be an organized outline of how it might be possible that the spherules have been mis-interpreted as part of the Meridiani layered deposit. I am working on it. If anyone wants to start in on me with the obvious objections, do it here for now. Maybe Dr. Burt would like to respond. No matter what the details of spherule formation in an impact or spherule deposition in the impact sediments, the very uniform distributions that we see are troublingly unlikely. Random distributions are possible from explosive dispersal but less likely than some kind of clustering because of the rapidly changing conditions in the surge cloud. The more-uniform-than-random distributions of spherules on rock characterised by MER-team analysis cannot be explained by impact surge.

[djellison]

How do you make hematite rich spheres sat on top of olivine rich soil? The two are essentially mutually exclusive minerals. The existence of one makes a VERY strong case against the formation of the other. You're going to have to some up with something extraordinary to do that.

You've still not touched the fact that the spherules are different and/or absent in different places.

And the earth analogues we've seen of concretions show a lot of concretions in not a lot of rock - the ratio is certainly similar, if not higher, than the one here.

And - if you're proposing the surface formation of the spheres at the same time as the surface formation of sulphate rich rock - why is there not sulphate rich rock everywhere? Why is there some forming and hiding spheres to a depth of a few mm here (pointing straight down at a piece of outcrop) but none there ( pointing to a patch of soil a metre to the right).

Surface formation has a lot more issues to tackle than any other theory I've seen. It seems like you're trying to solve one problem, by creating many more.

Doug