The mysterious fate of early micrometeoritic oxygen

Abstract

It is generally assumed that oxygen appeared much later in the history of the Earth, during the (Great Oxidation Event), GOE which lasted about 150 Myr, about 2 Gyr ago. But the causes of the GOE are still debated. For a long time, it was thought that it resulted from the biogenic activity of photosynthetic early life forms, which decomposed a fraction of the atmospheric CO2 to extract the carbon necessary to their growth. But Holland (2002) now argues that it might be associated with complex changes in the composition of volcanic gases! The fate of the fraction oxygen resulting from the photodissociation of micrometeoric water vapour in the early thermosphere, during the peak of the PHBomb, was not decrypted, yet. The unsolved problem is to trace back its reaction network with early materials. © Springer 2006.