Geologists have revealed how gold nuggets are formed
Gold deposits are often associated with quartz veins, from which up to 75% of the world's supply of this precious metal is extracted. However, the formation of large nuggets of gold remains a mystery.
Australian researchers from Monash University, led by Christopher Voisey, have proposed a new explanation based on the piezoelectric properties of quartz, which may contribute to the formation of gold during earthquakes.
They outlined their findings in a paper in the journal Nature Geoscience.
Gold is typically deposited from hot hydrothermal solutions that rise through cracks in the Earth's crust during seismic activity. The solutions reach temperatures of 200 to 650 degrees Celsius and pressures of up to five kilobars. However, to explain the formation of large gold nuggets, scientists have drawn on the hypothesis of gold nanoparticles collecting on the surface of quartz crystals.
The researchers conducted experiments with quartz samples from Australia's Fosterville mine. They simulated seismic waves and studied the deposition of gold from different solutions. The results showed that the piezoelectric potential of quartz crystals can promote electrochemical deposition of gold on their surface, especially in places where quartz crystals act as electrodes.
According to the researchers, the processes described by them can occur in nature.
This may explain the formation of nucleation and growth of large nuggets of gold in mining ore systems, which differ from gold deposits of other origins with a high content of metal, but without large accumulations, - explained the scientists in the article.
This mechanism explains how gold accumulates along cracks in quartz veins, creating unique deposits of large nuggets. According to the scientists, their study solves the more than century-old "gold nugget paradox".