Yeah, nice, uncontroversial geology! 40 million years ago, Nevada was split by a big, hot spreading ridge that ended up under Yellowstone. It's all 'Basin and Range', which are all extension grabens. At this time, lots of deep stuff flowed to the surface, carrying gold. Why does gold live deep? Perhaps when the early Earth was partially molten it separated out and settled deep due to it's high density. Perhaps at 40 km we have a sold layer of pure gold!
In an interview, Cline and Simon explained how they brainstormed scenarios on the origin of invisible gold during a retreat two years ago with the report's other authors, UNLV's Anthony Longo and John Muntean of the Bureau of Mines and Geology.
"We spent three days and two nights. We ate and slept thinking about this and divided up the questions and sorted out the answers," Cline said.
Now, that's geology!