"Could the Meridiani Spherules be Surficial?" Options

[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.

[Kye Goodwin]

Paxdan, re your 33, That's funny, Thanks. We have crossed the border to a far stranger place than Scotland. On Mars the mathematician's humourously cautious approach may be the most appropriate.

Doug, I do this for pleasure, and I've found that deadlines tend to spoil the fun, so your proposed deadline just isn't going to work for me. You have been keeping this thread alive with your keen interest. If there isn't any further interest by others this is likely to be my last post here. There are lines of evidence which I have not discussed suggesting that the spherules may be surficial, but I am not in any hurry.

In the fall of 2004 I read the original Brine-splat paper and soon thought that the Meridiani layered deposit had been well and simply explained. Impact-surge is such a good idea that I expected to be reading about it in the newspapers within weeks. I did read it in Nature a year later and have watched the impact surge idea slowly gain prominence in the discussion. The MER team now regularly addresses it as the primary alternative to their own work. It seems that you have decided to cut off Dr. Burt's thread. It is hard to understand why you wouldn't want the central debate about Meridiani to take place on your site.

I would be happy to hear from anyone with friendly or constructively critical comments about the ideas I have raised here. I haven't got very far yet with my research on the three occurences of hematite detected at Gusev. I have a paper copy of "Water alteration of rocks and soils on Mars at the Spirit rover site in Gusev Crater" from Nature July 2005, Haskin et al. It includes the detail that the coatings on Mazatzal "contain the only occurrence of CRYSTALLINE haematite detected to date on the basaltic plains of Gusev" (emphasis mine). The source of that is referenced but I ran out of dimes at the library that day and failed to copy the last page. If anyone is ahead of me on this, just what sort of crystalline haematite was detected on Mazatzal? This info-pauper will continue the search. This question may be pertinent to the impact spherule hypothesis because if grey hematite has been found in a form other than spherules it would suggest that a Mars process other than impact may be able to create grey hematite.

[djellison]

It seems that you have decided to cut off Dr. Burt's thread.

Indeed - Dr Burt agreed it was the right thing to do - it was going in circles and getting no futher. The same is true here - but given that this thread has been going for less time, I thought I'd give it a little longer before bringing it to a close.

In both cases - the threads have been more of a cyclical soap-box rather than scientific debate - and that's not something I want at UMSF.

Doug