Author Topic: Scientists find link between volcanism and the formation of copper ore  (Read 1580 times)


drocknut

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Re: Scientists find link between volcanism and the formation of copper ore
« Reply #1 on: February 21, 2015, 02:07:51 PM »
Interesting read, thanks for sharing.

HeySal

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Re: Scientists find link between volcanism and the formation of copper ore
« Reply #2 on: February 21, 2015, 09:17:12 PM »
It is interesting.  Volcanoes seem to produce a few nice little trinkets here and there.  What I find interesting is that some volcanoes do and some don't since it all comes up from the mantle.  I know there's something about how certain volcanoes produce gold, but don't remember anything about the specifics.  My brain seems to absorb only so much at once before it goes on overload.
Sal

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James

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Re: Scientists find link between volcanism and the formation of copper ore
« Reply #3 on: February 21, 2015, 11:29:53 PM »
It is interesting.  Volcanoes seem to produce a few nice little trinkets here and there.  What I find interesting is that some volcanoes do and some don't since it all comes up from the mantle.  I know there's something about how certain volcanoes produce gold, but don't remember anything about the specifics.  My brain seems to absorb only so much at once before it goes on overload.

From what I recall the process involves the intense heat and pressure on water making the water supercritical so it readily dissolves the gold.  As the gold dissolved in the water moves up through the cracks in the rock losing heat and pressure water loses solvency and the gold drops out of the water depositing in the cracks.  This would be vein gold.

What a lot of people don't realize is that most gold nuggets do not form this way.  Instead they are formed from bacteria.  Same with some forms of silver, such as threaded silver.  The first process I heard of about 30 some odd years ago was they found that Bacillus cereus bacteria would actually take the gold dissolved in water and plate itself like armor.  The somehow the would change the charge on the gold to attract more gold and the process continued forming larger and larger nuggets.  Same reason a place cleaned out of gold nuggets in a river can have new nuggets a decade later.  Other bacteria were found to ingest the gold salts dissolved in the water killing the bacteria in the process but leaving a cast of the gold.  More living bacteria would grow on that casting, ingest the gold salt killing the new bacteria forming a new casting, and again the process continues.

If you have gold nuggets or threaded gold look at them under the microscope. Often you will see growth patterns from the bacteria.  I have a great example packed away somewhere. If I can ever find it I will put it under the microscope and get some pics so you can see what I mean.  The growth pattern is definitely bacterial in origin.  Here are some examples of what I am talking about:

http://www.the-scientist.com/?articles.view/articleNo/34274/title/Microbial-Metallurgy/

http://archive.news.softpedia.com/news/The-Midas-Bug-the-Bacterial-Alchemist-31713.shtml

The first pic in this link looks somewhat similar to my gold nugget:

http://geotripper.blogspot.com/2010_07_01_archive.html

Now if this was formed geothermally and then washed out of a mountain and down a river, considering how soft gold is there is no way it would have maintained this shape.  These nuggets were definitely formed by bacterial action in the river.

HeySal

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Re: Scientists find link between volcanism and the formation of copper ore
« Reply #4 on: February 22, 2015, 08:18:55 PM »
I read about the gold and bacteria.  From what I read, prospecting companies now search for the bacteria to find gold.
Sal

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