Abstract
Abstract: The bio‐essential elements are demanded for the metabolic action of all living organisms. These elements are continuously supplied to biosphere through the elemental cycle on the surface Earth. The geochemical cycle of bio‐essential elements was most likely different in the pre‐biotic era (ca. 4.4 to 4.0 Ga) compared to the modern Earth. The difference was probably made by the absence of continents and biological mediation in the pre‐biotic environments. Geochemical cycle models of bio‐essential elements (P, B and Mo) on the pre‐biotic Earth are proposed in this study, and these models are examined using available geochemical data.The input flux of phosphorous in pre‐biotic oceans was probably dominated by submarine hydrothermal activities associated with carbonatized oceanic crusts. Such input flux by submarine hydrothermal activities is not known in the present‐day oceans, and probably a unique flux in the pre‐biotic oceans. Boron chemistry of pre‐biotic oceans was also controlled by submarine hydrothermal input flux. The Mo exchange between the pre‐biotic ocean and lithosphere may have restricted only at the submarine hydrothermal areas. These suggest that the submarine hydrothermal discharging areas were only locations to obtain bio‐essential elements for the earliest life. This model is consistent with the previously proposed model for hydrothermal origin of life.
Published Version
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