Theories on Gold Nugget Formation (Part 2)
(Did this Aussie nugget erode out or was it created by nanoparticles?)
Over the past decade some interesting new theories have been postulated on how gold nuggets are actually formed. In general, these theories don't fall into line with the old timers' view that gold nuggets were simply fragments of vein, lode, or reef material that had eroded out and then been further reduced in size and coarseness over time.
I've identified three main theories of gold formation that I'd like to bring to your attention.
I have to admit that when I first came across this theory on gold nugget formation I shook my head in disbelief. Microbes and gold? Were the so-called experts smoking crack or what? However, I decided to press on in an attempt to give the proponents of this theory the benefit of the doubt.
It seems that a while back researchers and scientists from the University of Adelaide in Australia discovered a nifty little bacterium called cupriavidus metallidurans that actually helps catalyze gold mineralization from a biological standpoint. Needless to say, this discovery made quite a few eyes pop wide open in the earth sciences as well as the mining industry at large.
Our Bacterial Buddy
The Aussie experts began to put two and two together when they found the same bacterial organism on gold grains recovered from sites as far apart as 2,174 miles (3,500 kilometers) in New South Wales and Northern Queensland. To quote one of the researchers, "It made us wonder why these organisms live in this particular environment. The results of this study point to their involvement in the active detoxification of Au complexes leading to formation of gold biominerals."
(Electron micrograph of gold nanoparticles in solution highly magnified.)
Since I work at a national science and engineering laboratory and am used to this sort of gobbledygook science speak I'll translate this in simpler terms: It seems our little bacterial buddy, cupriavidus metallidurans, has an amazing ability to defend itself against toxic metallic elements by inducing oxidation and an (as yet) unidentified gold gene cluster. In other words, this little sucker creates metallic gold.
Growing Gold Nuggets?
Granted, all of this occurs on a microbial scale and the gold particles that cupriavidus metallidurans creates as a defense fall into the nano-particle range. That's extremely small...in fact, to my knowledge these gold particles can only be seen using electron microscopes.
So how does gold nugget formation tie in here? The Australian scientists believe that the nanoparticles of gold that cupriavidus metallidurans creates build and build over time (lots of time I assume) and eventually contribute to the growth of gold nuggets out in the field.
One Hell of a Theory
Can you imagine the expression on the faces of the old timers if you could run this theory past them? Still, after all is said and done, it's one hell of a theory that does have a solid basis in scientific fact.
Bottom line? Ya gotta love those Aussies...they're a different breed for sure.
Good luck out there.
If you liked this post, you may want to read: "Large Nuggets in Australia (Part 2)"
(c) Jim Rocha 2012
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