This would be the secret by which giant gold nuggets are generated

Published:

Sep 3, 2024 10:49 GMT

The current, widely accepted theory does not fully explain the formation of large gold nuggets, according to the authors of the new study.

A research team led by geologists at Monash University in Australia, Postulated a revolutionary theory suggesting that electricity generated by earthquakes could be the secret behind the mysterious formation of giant gold nuggets, which are often found embedded in quartz veins formed in seismic-related deposits.

“The standard explanation is that gold precipitates from hot, water-rich fluids as they flow through cracks in the Earth’s crust,” explains Chris Voisey, who led the study. “As these fluids cool or undergo chemical changes, the gold separates out and becomes trapped in the quartz veins,” he continues.While this theory is widely accepted, it does not fully explain the formation of large gold nuggets.especially considering that the concentration of gold in these fluids is extremely low,” he noted.

An interesting property of quartz

Quartz, the mineral that normally hosts these gold deposits, has the natural property of generating an electric charge when subjected to tension. This phenomenon, called piezoelectricity, is used in everyday items such as watches and lighters. By applying a small mechanical force on the quartz, it creates a significant voltage.The scientists wanted to find out whether the mechanical stress generated by earthquakes can do something similar inside the Earth and whether this piezoelectricity could explain the formation of these abundant veins of gold in quartz.

Theory put to the test

The research team tested the new concept by reproducing the conditions that quartz might experience during an earthquake. They immersed quartz crystals in a gold-rich fluid and applied stress to simulate the stress of seismic shaking. The quartz samples were then examined by microscopy.

“The results were surprising,” said Tomkins, a research collaborator.The pressed quartz not only electrochemically deposited gold on its surface, but also formed and accumulated gold nanoparticles.“He said. “Interestingly, the gold had a tendency to settle on top of existing gold grains rather than forming new ones,” he added.

The scientists explained that while quartz is an electrical insulator, gold is a conductor, so once some gold is deposited, it becomes a focal point for further growth, effectively “coating” the gold grains with more gold.”Our discovery provides a plausible explanation for the formation of large gold nuggets in quartz veins.“Voisey said.

As quartz is subjected to repeated stresses due to earthquakes, it generates piezoelectric voltages that can reduce dissolved gold in the surrounding fluid, causing it to sediment.In essence, quartz acts as a natural battery, with gold as an electrode, slowly accumulating more gold with each seismic event.“Voisey said. The study was published this Monday in Nature Geoscience.