An alternative hypothesis for the origin of the banded iron formations and the synthesis of prebiotic molecules is presented here. I show the importance of considering water near its supercritical point and at alkaline pH. It is based on the chemical equation for the anoxic oxidation of ferrous iron into ferric iron at high-subcritical conditions of water and high pH, that I extract from E-pH diagrams drawn for corrosion purposes (Geophysical Research Abstracts Vol 15, EGU2013-22 Bassez 2013, Orig Life Evol Biosph 45(1):5-13, Bassez 2015, Procedia Earth Planet Sci 17, 492-495, Bassez 2017a, Orig Life Evol Biosph 47:453-480, Bassez 2017b). The sudden change in solubility of silica, SiO2, at the critical point of water is also considered. It is shown that under these temperatures and pressures, ferric oxides and ferric silicates can form in anoxic terrains. No FeII oxidation by UV light, neither by oxygen is needed to explain the minerals of the Banded Iron Formations. The intervention of any kind of microorganisms, either sulfate-reducing, or FeII-oxidizing or O2-producing, is not required. The chemical equation for the anoxic oxidation of ferrous iron is applied to the hydrolyses of fayalite, Fe2SiO4 and ferrosilite, FeSiO3. It is shown that the BIF minerals of the Hamersley Group, Western Australia, and the Transvaal Supergroup, South Africa, are those of fayalite and ferrosilite hydrolyses and carbonations. The dissolution of crustal fayalite and ferrosilite during water-rock interaction needs to occur at T&P just below the critical point of water and in a rising water which is undersaturated in SiO2. Minerals of BIFs which can then be ejected at the surface from venting arcs are ferric oxide hydroxides, hematite, FeIII-greenalite, siderite. The greenalite dehydrated product minnesotaite forms when rising water becomes supersaturated in SiO2, as also riebeckite and stilpnomelane. Long lengths of siderite without ferric oxides neither ferric silicates can occur since the exothermic siderite formation is not so much dependent in T&P. It is also shown that the H2 which is released during hydrolysis/oxidation of fayalite/ferrosilite can lead to components of life, such as macromolecules of amino acids which are synthesized from mixtures of (CO, N2, H2O) in Sabatier-Senderens/Fischer-Tropsch & Haber-Bosch reactions or microwave or gamma-ray excitation reactions. I propose that such geobiotropic synthesis may occur inside fluid inclusions of BIFs, in the silica chert, hematite, FeIII-greenalite or siderite. Therefore, the combination of high-subcritical conditions of water, high solubility of SiO2 at these T&P values, formation of CO also at these T&P, high pH and anoxic water, leads to the formation of ferric minerals and prebiotic molecules in the process of geobiotropy.

中文翻译：

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在超临界点附近和碱性pH下的水可在缺氧条件下生产三氧化二铁和硅酸盐。带状铁层中观察到的矿物合成以及流体包裹体内部相关的地球生物化学的新假说。

本文介绍了带状铁形成的起源和益生元分子合成的另一种假设。我展示了考虑在超临界点附近和碱性pH下使用水的重要性。它基于在水和高pH的高亚临界条件下将亚铁氧化还原为三价铁的化学方程式，我从出于腐蚀目的绘制的E-pH图中提取（地球物理研究摘要第15卷，EGU2013-22） Bassez 2013，Orig Life Evol Biosph 45（1）：5-13，Bassez 2015，Procedia Earth Planet Sci 17，492-495，Bassez 2017a，Orig Life Evol Biosph 47：453-480，Bassez 2017b）。还考虑了二氧化硅（SiO2）在水的临界点的溶解度突然变化。结果表明，在这些温度和压力下，氧化铁和硅酸铁可在缺氧地区形成。紫外线不会使FeII氧化，也不需要氧来解释带状铁层的矿物。不需要干预任何类型的微生物，无论是硫酸盐还原型，FeII氧化型还是O2产生型。亚铁的缺氧氧化化学方程式适用于铁橄榄石Fe2SiO4和硅铁矿FeSiO3的水解。结果表明，西澳大利亚州的哈默斯利集团和南非的德兰士瓦超级集团的BIF矿物是铁橄榄石和铁硅石水解和碳化的矿物。在水与岩石相互作用过程中，地幔铁橄榄石和硅铁矿的溶解需要在T＆P处在水的临界点以下，并且在SiO2中不饱和的上升水中发生。可以从排气电弧中喷出的BIFs矿物为氢氧化铁氢氧化物，赤铁矿，FeIII绿铁矿，菱铁矿。当上升的水在SiO2中变得过饱和时，就会形成绿藻石脱水产物明尼苏达石，此外还有里贝石和stilpnomelane。长长的菱铁矿没有三氧化二铁，硅酸铁也不会出现，因为放热的菱铁矿的形成与T＆P的关系不大。还显示在铁橄榄石/硅铝石的水解/氧化过程中释放的H2可以导致生命的组成部分，例如从（CO，N2，H2O）的混合物在Sabatier-Senderens / Fischer中合成的氨基酸大分子-Tropsch和Haber-Bosch反应或微波或伽马射线激发反应。我建议，这种地生物合成可能发生在BIFs的流体包裹体内部，例如硅质硅cher石，赤铁矿，FeIII-绿铁矿或菱铁矿。因此，水的高亚临界条件，在这些T＆P值下SiO2的高溶解度，在这些T＆P处也形成CO，高pH值和缺氧水的组合导致在地球生物变质过程中形成铁矿物质和益生元。