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In the process of serpentinisation, protons act as oxidising agents for ferrous ions, which results in the production of dihydrogen gas. How is that possible?
Dihydrogen being a strong reductor, I woud expect this reaction spontaneously going the opposite way.

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    $\begingroup$ Maybe you should consider asking it in chemistry.stackexchange.com $\endgroup$ – arkaia May 29 '15 at 13:44
  • $\begingroup$ @aretxabaleta I disagree - this is completely related to earth science! As for the question, this might be extremely relevant: Thermodynamic constraints on hydrogen generation during serpentinization of ultramafic rocks. This might be paywalled though, unless you have an institutional subscription. $\endgroup$ – Gimelist May 30 '15 at 11:45
  • $\begingroup$ @Michael, I don't think it does not belong here. My suggestion comes from the fact that it has not received as much attention as some other questions and it does not have an answer yet. I know that chemistry currently gets more action than earth science and thus, my suggestion. I think it is fine in this site if the author is ok with it. $\endgroup$ – arkaia May 31 '15 at 1:17
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Under normal circumstances your suggestion might be correct, but bear in mind that the serpentinization reaction takes place under very negative Eh, and very high pH conditions (pH 12 or more). This abnormal combination is right on the boundary of water-hydrogen stability conditions. In hyperalkaline springs, which result from the reaction water + peridotite = serpentine, there is hardly a free molecule of oxygen left in solution.

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