In Striking It Rich with ‘Instant Gold’ (17 April 2013) Timothy L. Clarey points us to a Nature Geoscience paper called “Flash vaporization during earthquakes evidenced by gold deposits.” The gist is as follows:
The two scientists found that faulting events are key to gold deposit formation, where rocks split apart and quickly slip past one another, causing earthquakes. Faults through solid rock are never straight. Instead, they follow zigzag patterns that look like chain lightening and create small voids—openings in the rocks called “jogs.” Fast-forming jogs create instantaneous drops in pressure during movement, causing superheated deep waters to almost instantly “flash vaporize,” leaving behind thin coatings of gold and quartz.
Repeated earthquakes could build up the gold to levels that would be economical to mine. Continue reading