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To: VadeRetro
So you're punting on the oxygen.

My link to the Duke university description makes no mention of free oxygen. It describes a neutral oxidizing atmosphere. "Oxidizing" as a usual chemical reference is the tendency for something to contribute an electron as displayed here Oxidizing Agents

Oxidation is defined in chemistry as gain of oxygen, loss of hydrogen or loss of electrons; the loss of electrons enables you to calculate an oxidation state.

You attempted to bring in Wells and a consideration of free oxygen and I refuse to be tied to that argument. I answered your BIF contention and have answered the pyrite and uraninite considerations. In the process of answering your claims I found information as of 2 months ago that lends evidence to the viability of a prebiotic atmosphere containing free oxygen. That is nice, and would put a bigger nail in the coffin of a reducing atmosphere but an oxidizing atmosphere is enough problem for the alleged reducing atmosphere. The reducing atmosphere of the Miller-Urey experiment has been pretty much abandoned. Now the Miller-Urey proponents are clinging to hope that a neutral atmosphere can explain the chemistry required.

So the "accepted" situation at this point is not a Miller-Urey atmosphere. Evidence is building that free oxygen in the primordial atmosphere is not eliminated as a possibility. The experiments I linked mean things. They are that the partially oxidized minerals UO2(how did it get that way?) and FeS2 are not a conclusive indicator of the absence of free oxygen in the atmosphere. You'll note that the environments for the problematic minerals are beaches and streams. This has a reason. It is also an indication. There were deposits of these materials that eroded or the materials were formed by a process at these locales.

635 posted on 06/01/2002 10:33:10 AM PDT by AndrewC
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To: AndrewC
I answered your BIF contention and have answered the pyrite and uraninite considerations. . .

618.

649 posted on 06/01/2002 11:40:38 AM PDT by VadeRetro
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To: AndrewC
Note that the concentration of atmospheric oxygen required to rust a static mineral deposit can be very low, compared to, say, the concentration required to degrade organic materials being continually introduced by active processes.
651 posted on 06/01/2002 11:53:14 AM PDT by VadeRetro
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