Scientists say that gold deposits found in rock layers along active fault lines were created by earthquakes.
A team of geologists has estimated that 80% of the planet’s commercial gold deposits were created when strong earthquakes produced enormous pressure that tore rock layers apart, causing water containing gold particles inside the layers to vaporize, New Scientist notes.
The resulting gold-rich residue is left in the rocks along the fault line. It had long been understood that gold is deposited in rock seams by water, but the process behind the depositing was never fully understood.
According to the research, strong earthquakes force open cracks in rock layers at the speed of sound. As the cracks form, water in the surrounding rock is drawn into the voids where the pressure drops sharply, flash-vaporizing the water.
As the water vaporizes, minerals, including gold, are deposited along the cracks in the rock. Over time and repeated quakes along time fault, large amounts of gold can be deposited.
By the standards of geological time — a few hundred thousand years — the process is relatively quick.