GOLD NEWS

Researchers unravel how gold reaches surface of Earth

Sun Dec 29 2024

An international team of researchers have identified a complex of gold and sulphur that helps scientists get a clearer understanding of how gold makes its way to the surface of the Earth. The gold within ore deposits along the Pacific Ring of Fire, a chain of volcanoes that stretches across the Earth originates deep within the mantle and wells up towards the surface, transported by magma. However, scientists did not have a clear understanding of the underlying processes involved. The researchers have used numerical modelling to reveal the conditions under which gold enriched magmas rise to the surface.

The model reveals the role played by a gold-trisulphur complex, that was previously predicted in theory, and whose existence has been the focus of vigorous scientific debate. This gold-trisulphur complex requires an exacting set of pressure and temperature conditions to form between50 and 80 kilometres beneath active volcanoes. The volcanoes cause the gold to move from the mantle into the magmas that eventually make it to the surface of the Earth. While gold is self-sufficient in the mantle above a subducting ocean plate, it readily bonds with trisulphur to form the complex when fluid contianing the trisulphur ion is introduced from the subducting plate to the mantle. This complex is very mobile within the magma.

A robust thermodynamical model

A paper describing the findings has been published in the Proceedings of the National Academy of Sciences. One of the coauthors of the paper, Adam Simon says, “This thermodynamic model that we’ve now published is the first to reveal the presence of the gold-trisulfur complex that we previously did not know existed at these conditions. This offers the most plausible explanation for the very high concentrations of gold in some mineral systems in subduction zone environments.” While gold was known to form complexes with various sulphur ions, this is the first time that the existence of a gold-trisulphur complex has been supported by a compelling thermodynamical model.

Source: https://www.news9live.com