 | Three billion years ago, the atmosphere contained almost no oxygen and the air consisted primarily of gases containing sulphur. Gases like hydrogen sulphide were pumped out of volcaneos, rising to form clouds that then fell as acid rain on the mountains.
In a new study published in Nature Geoscience entitled, "Witwatersrand gold deposits formed by volcanic rain, anoxic rivers and Archaean life", Christoph Heinrich, a professor of Economic Geology, argues that the gold didn't just get moved by the rivers – it was first dissolved chemically in volcanic rain. Heinrich's theory is that the gold would have formed soluble complexes with the sulphur, which were then absorbed by water, before finally being separated by primitive microbes to form the gold. | |