Majority of the world's gold deposits formed by earthquakes

It's always interesting to learn how certain rocks are formed, and gold is one of those elements that is so precious and rare, yet very few people have any idea on how it's formed in the Earth. According to a study conducted by a group of Australian geologists, 80% of the world's gold deposits are actually formed in the blink of an eye thanks to earthquakes.

The process is called "flash vaporization," which happens deep below the Earth's crust, going down as far as 18 miles below, fault cavities from earthquakes fill up with fluids and are subject to extremely high temperatures and pressure, which leads to instant vaporization of these fluids that contain dissolved substances like gold and silicate minerals.

This process has always been theorized, but it's been unclear as far as how drastic the pressure changes are. It turns out that an earthquake can create a dramatic drop in pressure, which forces the fluid to expand to as much as 130,000 times its original size — all of which happens in a split second, hence "flash vaporization."

Of course, the link between gold deposits and earthquakes is nothing new, but the study finally quantifies how drastic the pressure changes are far beneath the Earth's surface. About two-thirds of all known gold deposits consist of gold veins that are formed deep underground and can be mined directly, with 45% of the world's gold mostly coming from South Africa.

[via io9]

Image via Flickr