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Author Topic: How did Earth get its gold?  (Read 7900 times)

thedoc

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How did Earth get its gold?
« on: 08/09/2011 16:39:29 »
Gold, platinum and many other precious metals are more common in the Earth's crust than models of the planet's formation would predict, causing some to question the current theory. But now it looks like the planet's surface was re-endowed with "bling" by a late meteor shower...

Read the whole story on our website by clicking here

  
« Last Edit: 08/09/2011 16:39:29 by _system »

CliffordK

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How did Earth get its gold?
« Reply #1 on: 08/09/2011 19:44:57 »
Has there been a significant amount of gold found in regolith or moon rock?

Meteorites, of course, get concentrated with heavy metals due to their shedding the lighter materials in the upper atmosphere, which presumably comes down much more diffusely.

Gold is often found in veins from igneous processes, and wouldn't seem to require delivery by asteroids, but rather requires volcanic and seismic activity to bring it to the surface.

Is this early asteroid bombardment a late extension of the planet formation?

Mazurka

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How did Earth get its gold?
« Reply #2 on: 09/09/2011 10:58:07 »
This theory has been around since the 70's - logic dictates that heavy elements present such as gold when the earth accreted would have ended up in the core. 

The various processes whereby gold gets concentrated into veins etc are not thought to go as deep as the core.

The late heavy bombardment event occurred when the development of the core/ mantle was nearly (if not totally) complete.

The isotopic geochemistry of tungstun (gold inconvieniently lacking isotopes) shows a difference between before and after the late heavy bombardment.

Don_1

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How did Earth get its gold?
« Reply #3 on: 04/10/2011 12:34:49 »
I hope Gordon Brown doesn't read this! He'll flog it on www.ebay.mars for a couple of dollars an ounce.

 

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