In a breakthrough that reads like alchemy, scientists at the University of Geneva have solved a long-standing mystery about how gold travels through the Earth’s crust to form valuable deposits of this precious metal. Their discovery reveals that a particular form of sulfur acts as nature’s gold courier, challenging previous theories about how precious metal deposits form.
The journey of gold from deep within the Earth to mineable deposits has long puzzled geologists. Now, researchers have identified that bisulphide, a specific form of sulfur, plays a crucial role in transporting gold through superhot fluids released by magma – the molten rock that eventually becomes the volcanic formations we see at the surface.
“Due to the drop in pressure, magmas rising towards the Earth’s surface saturate a water-rich fluid, which is then released as magmatic fluid bubbles, leaving a silicate melt behind,” explains Stefan Farsang, lead author of the study published in Nature Geoscience.
In a breakthrough that reads like alchemy, scientists at the University of Geneva have solved a long-standing mystery about how gold travels through the Earth’s crust to form valuable deposits of this precious metal. Their discovery reveals that a particular form of sulfur acts as nature’s gold courier, challenging previous theories about how precious metal deposits form.
The journey of gold from deep within the Earth to mineable deposits has long puzzled geologists. Now, researchers have identified that bisulphide, a specific form of sulfur, plays a crucial role in transporting gold through superhot fluids released by magma – the molten rock that eventually becomes the volcanic formations we see at the surface.
“Due to the drop in pressure, magmas rising towards the Earth’s surface saturate a water-rich fluid, which is then released as magmatic fluid bubbles, leaving a silicate melt behind,” explains Stefan Farsang, lead author of the study published in Nature Geoscience.
This groundbreaking methodology allowed the scientists to observe something previous researchers couldn’t: the exact chemical form of sulfur present in these magmatic fluids. Using laser analysis techniques, they discovered that bisulphide, along with hydrogen sulfide and sulfur dioxide, are the main forms of sulfur present at these extreme temperatures.
The findings overturn a 2011 study that had suggested different sulfur compounds were responsible for gold transport.
“By carefully choosing our laser wavelengths, we also showed that in previous studies, the amount of sulfur radicals in geologic fluids was severely overestimated and that the results of the 2011 study were in fact based on a measurement artifact,” says Farsang, effectively settling a decade-long debate in the geological community.
Since much of the world’s gold and copper comes from deposits formed by these magma-derived fluids, understanding exactly how they form could also aid in future mineral exploration efforts.
Think of it as understanding nature’s own delivery system: just as a postal service needs specific vehicles and routes to deliver packages, gold needs specific chemical compounds and conditions to move through Earth’s crust. By identifying bisulphide as the primary “delivery vehicle,” scientists have mapped out one of nature’s most valuable transportation networks.
The study emerged from the complex interaction between tectonic plates – the massive sections of Earth’s crust that slowly move against each other. When one plate slides beneath another, it generates magma rich in volatile elements like water, sulphur, and chlorine. As this magma rises toward the surface, it releases fluids that carry dissolved metals with them – a process that ultimately leads to the formation of the gold deposits that humans have prized throughout history.
This new understanding of gold’s journey through the Earth not only helps explain how existing deposits formed but could also guide future exploration efforts, potentially making gold mining more efficient and targeted.
Source : https://studyfinds.org/how-gold-reaches-earths-surface/
