"Could the Meridiani Spherules be Surficial?" |
"Could the Meridiani Spherules be Surficial?" |
Jul 10 2007, 04:37 PM
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Junior Member Group: Members Posts: 42 Joined: 2-July 07 Member No.: 2646 |
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. |
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Jul 13 2007, 07:01 PM
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Junior Member Group: Members Posts: 42 Joined: 2-July 07 Member No.: 2646 |
denis, re your 26, Thanks. On your first point: I have noticed that spherules occur less frequently on rock than on soil. This is pretty well established for spherules attached to rock, but it also seems to be true for loose spherules. The densest coverings of spherules seem to always be on soil and I tend to think that the presence of soil is somehow causing the denser spherule populations. The causality can easily be turned around, however, and soil explained by the presence of spherules, which would reduce wind at the surface and allow soil or dust to accumulate between them. Still, I would GUESS that your clustering of loose spherules within Endurance could be caused by the generally shallow and patchy soil cover in Endurance compared with the plains, that is, a mixture of rock and soil substrates is available.
You mention limited accumulations of spherules in Endurance but I don't see any accumulations that appear to be connected to gravity movements, and I don't think that there are overall more spherules per area in Endurance than on the plains. You write of "short distance interaction between spherules". The average distance between spherules attached to rock surfaces is much greater than the average distance between spherules loose on soil, so if the ancient subsurface concretion model is used, wouldn't a long (or at least longer) distance interaction be required to explain them? What is the approximate "short distance" you are referring to and how does it compare with the average separation of spherules attached to rock? Dr. Burt might laugh at the idea that spherules forming in a groundwater system could be controlled by nothing but the distance to nearby spherules, and I have to agree with the criticism. The MER team have been forced to propose that their spherule-building aquifer was uniformly permeated at all depths with water and solutes and that the water did not move, which is asking a lot. A surface nodule explanation isn't obviously any better at explaining the spaced-apart spherule distributions, but it does avoid (through vagueness) having to invoke groundwater and earth-like concretion formation. It may help to explain why the more-uniform-than-random distributions are clear at the surface - it is in the surface environment that spherule growth has taken place and been controlled. |
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