I was perusing an issue of NewScientist (an old one--from January 20-26 of this year) and found a fascinating article about accelerated gold formation. The article link is here, but unfortunately you can't view most of it without a subscription. (Notice I shamelessly stole their title for use on this post.) Luckily, there's another article on the same subject here, published in the Geotimes.

In the article science journalist Phil McKenna explores how theories of slow gold formation have been turned on their head in light of recent empirical evidence that gold can form quickly. At the center of interest is the Lihir gold mine on Papua New Guinea's Lihir Island, where lies a gold deposit containing around 1600 metric tons of the lovely stuff. The mine is unique not only for the large size of its deposit but for the ongoing volcanic activity in the region. Hydrothermal activity is continuous at the mine, and several miles south of the island there are seafloor vents containing the world's highest underwater gold concentration rate.

 It turns out that the Lihir deposit is still being formed as you read this. Kevin Brown, a geochemist from a New Zealand research center, knew gold deposits could form from the heated water in hydrothermal vents. As the water turned into steam, minerals--including gold, if the geologic location was right--were left behind as a deposit. He decided to conduct a test at Lihir to see if the deposits there might have been formed in this way. Sure enough.

 It turns out that at the current rate of hydrothermal activity, 24 new kilograms of gold are accruing to the Liher deposit every year. At that rate, says Brown and his colleague, Stuart Simmons, the entire deposit could have formed in 55,000 years. Their findings were published in Science last year.

Christoph Heinrich, a Zurich researcher who has discovered very high concentrations of gold trapped in quartz crystals, thinks the deposit at Lihir could have formed even faster:

 [Heinrich] thinks the hydrothermal system investigated by Brown and Simmons may have passed its prime and could once have contained greater concentrations of gold. "We have found fluids that had a thousand times higher concentrations," Heinrich says of sites he has studied in Argentina, Indonesia, south-east Europe and the US. "If you spin the same argument that they are using with a thousand times higher concentrations, then the time it takes might have been a thousand times shorter--50 or 60 years."   --NewScientist

 All this to say that, surprise, gold can form quickly. Please be aware that not all geologists are happy about this prospect, particularly when it conflicts with other favored gold deposition theories. Says Stuart Simmons, "Geologists hate each other for life over their opinions on this stuff. These are highly emotive debates that take on an almost religious fervor."

In case you were wondering, Simmons and Brown have already tried designing a gold trap. (Were you hoping you had thought of it first?) Unfortunately, the cost of collecting the gold would appear to outweigh the metal's value. Harvesting deposits from hydrothermal vents would probably have to be incorporated into existing hydrothermal plants in order to be cost effective. Simmons and Brown are still working on that one.

Image copyright: Silvia Silva. Used by permission.