An international team of researchers, including a scientist from the University of Michigan, has proposed a new model to explain why gold, despite being more abundant in the Earth’s bulk composition than lead, is found at the surface. Published on December 29, 2024, the study focuses on how molten rocks (magma) transport gold from the Earth’s mantle to the surface.
Historically, gold atoms are trapped in the mantle due to high pressure and heat, making the presence of gold on the surface a mystery. Previous theories didn’t fully explain how gold moves upward, but this new approach highlights the role of sulfur in creating a gold-sulfur complex, which allows gold to remain molten and move through the mantle. This complex forms when sulfur-rich liquid interacts with mantle rocks under high pressure.
The research identifies subduction zones—regions where one tectonic plate slides beneath another—as key areas for gold transport due to the release of water and sulfur that fosters necessary chemical reactions. Laboratory experiments mimicked conditions under active volcanoes and confirmed that sulfur enhances gold’s mobility, suggesting a link between these geological settings and the largest gold deposits on Earth.
The findings have implications for mineral exploration, particularly in subduction zones around the Pacific Ocean, indicating that sulfur-rich fluids could also transport other metals. The study aims to refine models of how heat, pressure, and chemistry interact to influence gold deposits, guiding future field studies in volcanic areas. This advancement not only clarifies gold’s geological journey but also opens new avenues for resource discovery.
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