Earthquakes seem to be the key force behind the creation of large gold nuggets

By Eric Ralls – earth.com

Crack open a chunk of white quartz from a gold mine and you might see bright metal streaks inside. For more than a century, geologists looked at scenes like that and said, “Gold got here in hot water.”

They meant that super‑hot fluids moved through cracks in the rock, carried dissolved gold, and then left that gold behind when conditions changed.

That idea explains a lot, but it raises a tough question: those fluids usually carry only tiny amounts of gold compared with the volume of water, so how can that kind of solution leave behind large nuggets inside quartz, a mineral that hardly reacts with anything?

That puzzle still bothers geologists.