A team of researchers, including a University of Michigan scientist, has uncovered a new gold-sulfur complex that sheds light on how gold deposits form. The research uses numerical modeling to show that a specific condition in the Earth’s mantle can cause gold to be transferred into magmas and eventually reach the surface.
The model reveals the importance of this gold-trisulfur complex under high pressures and temperatures, 30-50 miles beneath active volcanoes. This complex causes gold to bond with trisulfur, making it more mobile in magma. The team’s results suggest that this is the key explanation for the high concentrations of gold found in certain mineral systems.
Gold deposits are formed in subduction zones, where a continental plate is being pushed under another. In these areas, magma from the Earth’s mantle can rise to the surface. The researchers found that when the conditions are right, a fluid containing trisulfur ions can be added to the mantle, causing gold to bond with trisulfur and form this complex.
This study is significant because it provides a robust thermodynamic model for the existence and importance of the gold-trisulfur complex. The researchers used lab experiments and modeling to identify this new complex and develop a predictive model that can be applied to real-world conditions. The results have the potential to improve our understanding of how gold deposits form and can have a positive impact on exploration efforts.
The study, published in the Proceedings of the National Academy of Sciences, builds on existing research and offers new insights into the formation of giant gold deposits in subduction zones.
Source: https://phys.org/news/2024-12-thermodynamic-gold-earth-surface.html