Gold could be deposited in Earth’s crust almost instantaneously during earthquakes, reports a study published online this week in Nature Geoscience. Repeated earthquakes could therefore lead to the build up of economic-grade gold deposits.
Dion Weatherley and Richard Henley use a numerical model to simulate events in fluid-filled cavity in the crust following an earthquake. They show that a drop in pressure within the cavity, generated by an earthquake splitting the rocks farther apart, would cause the fluid to rapidly expand and vaporize. Any gold that was previously dissolved in the fluids would precipitate almost immediately, creating small gold deposits that build up during successive earthquakes.