Posted on 03/18/2013 7:42:33 PM PDT by neverdem
Pressure changes cause precious metal to deposit each time the crust moves.
Scientists have long known that veins of gold are formed by mineral deposition from hot fluids flowing through cracks deep in Earth’s crust. But a study published today in Nature Geoscience1 has found that the process can occur almost instantaneously — possibly within a few tenths of a second.
The process takes place along 'fault jogs' — sideways zigzag cracks that connect the main fault lines in rock, says first author Dion Weatherley, a seismologist at the University of Queensland in Brisbane, Australia.
When an earthquake hits, the sides of the main fault lines slip along the direction of the fault, rubbing against each other. But the fault jogs simply open up. Weatherley and his co-author, geochemist Richard Henley at the Australian National University in Canberra, wondered what happens to fluids circulating through these fault jogs at the time of the earthquake.
What their calculations revealed was stunning: a rapid depressurization that sees the normal high-pressure conditions deep within Earth drop to pressures close to those we experience at the surface.
For example, a magnitude-4 earthquake at a depth of 11 kilometres would cause the pressure in a suddenly opening fault jog to drop from 290 megapascals (MPa) to 0.2 MPa. (By comparison, air pressure at sea level is 0.1 MPa.) “So you’re looking at a 1,000-fold reduction in pressure,” Weatherley says.
Flash in the pan
When mineral-laden water at around 390 °C is subjected to that kind of pressure drop, Weatherley says, the liquid rapidly vaporizes and the minerals in the now-supersaturated water crystallize almost instantly — a process that engineers call flash vaporization or flash deposition. The effect, he says, “is sufficiently large that quartz and any of its associated minerals and metals will fall out...”
(Excerpt) Read more at nature.com ...
wow. amazing. God’s forge: His earth.
Interesting. But there still needs to be a high concentration of gold within the host rock for this to occur. There are faults all over the world that have no precious metals associated with them.
The authors would probably hypothesize that water with certain minerals in solution must be brought under pressure to ~390C, then suddenly de-pressurized, vaporizing the water.
What minerals should be in solution?
It was proven long ago.
Gold Chloride.
That's not cost effective, even with gold as the end product.
I like this approach from UCSB:
all you need is some other stuff made of elements with atomic number smaller than gold and a source of neutrons. If you feed in the neutrons appropriately you can build up the nucleus up in mass until you get gold nuclei. Along the way, some of the the neutrons will decay into a proton and electron and neutrino. The nucleus ejects the electron and neutrino and the atomic number steps up by one since there is now an extra proton in the nucleus.
This is not supposed to be cost effective either, but perhaps collider research will produce something better.
I’m not suggesting we try it... but the crystalline gold you find in quartz deposits was at one time gold chloride solution that dropped in temperature and pressure... that makes the gold crystallize out of the solution.
Distinctive virus behind mystery horse disease
Most popular human cell in science gets sequenced
FReepmail me if you want on or off my health and science ping list.
Still, I would like to make gold the way nature did. This would reduce the cost of materials. Energy inputs would be substantial, however.
31 and a fraction grams in a Troy ounce.
Can we please stop posting this? There have already been at least three separate posts concerning this just in this afternoon -is the FR ‘search’ function really that inefficient?
Propaganda to keep gold prices suppressed! :p
"When mineral-laden water at around 390 °C is subjected to that kind of pressure drop, Weatherley says, the liquid rapidly vaporizes and the minerals in the now-supersaturated water crystallize almost instantly — a process that engineers call flash vaporization or flash deposition."
Yo Einstein! Pardon me for having a chemistry major, but not one of those posts describe flash vaporization or flash deposition. Those terms are now keywords. Maybe their links did, but people don't always follow links.
P.S. I'm not that obsessive compulsive. I just do title searches.
Mine (pun intended) was from another source.........
I do title searches before I post news that involves popular subjects or well known people.
However, I’m glad Free Republic has stopped deleting redundant posts on more obscure news.
I’ll bet several hundred people read the “Gold” story who would not otherwise have seen it.
I think most people read Free Republic the same way I do.
First, I check the right hand margin for interesting titles.
Second, I scan or read all the stories on the most current page.
I would miss many important stories each month if Free Republic deleted all the redundancies.
Well, if you find a cost-effective method to produce gold, then the value of gold will drop precipitously, and then it wouldn’t be any good to us except for industrial uses. So, what is the point?
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