How is Gold Formed and Distributed in Nature?

[dragoneyes001]

I asked this in another thread and was told this question should have had its own thread so as to not hijack the other thread.
That question was: Has anyone calculated how much if any gold is produced in the sun? which is likely almost none do to the differences between fusion and fission and the creation of random/not so random elements in the processes of each. the answer I received from the other thread was that gold is more likely to be produced in a super nova...which makes sense yet in that case we'd have to expect gold to be in pretty small individual groups if not just fragments?

After thinking this over some I had a few other questions about gold such as how does the element attract to itself since on Earth we find gold in veins more often than not accompanied by quarts veins. if the element is a product of random chance (so to speak) what made it collect in batches during the molten rock stage before it becomes a vein? also why are gold and quarts found as somewhat partners during the forming of stone?

 

[Danger]

Hi. This is just a quick comment rather than a real answer. Fusion stops when iron is produced. Heavier elements can't do it. Transmutation occurs under special conditions (nova or supernova) wherein neutrons are captured by the nuclei of iron and its descendants rather than causing a chain reaction explosion. That's drastically simplified from what really happens, but maybe will give you an idea.

 

[aroc91]

To put it simply, elements separate out due to their differing densities.

http://en.wikipedia.org/wiki/Iron_catastrophe
http://en.wikipedia.org/wiki/Planetary_differentiation

 

[Bandersnatch]

which makes sense yet in that case we'd have to expect gold to be in pretty small individual groups if not just fragments?

I don't quite follow the question here. Could you perhaps rephrase?

As for the second part, have a look here:
http://en.wikipedia.org/wiki/Ore_genesis
It's a fascinating read. In short, mineral concentrations can form in a number of processes, including precipitation from mineral-bearing deep water along faults (to form veins), crystallisation from magma as it cools (allowing different minerals to crystallise at different times), and even due to bacterial activity (http://en.wikipedia.org/wiki/Delftia_acidovorans).

These pages might be of use as well:
http://en.wikipedia.org/wiki/Gold#Occurrence
http://en.wikipedia.org/wiki/Vein_(geology)
http://en.wikipedia.org/wiki/Lode

 

[dragoneyes001]

@Bandersnatch what i meant was in a nova you'd expect most of the effluent from the explosion to be on a near molecular size or dust sized with some larger groups obviously mixed in. stuff to create the clouds which we believe created planets and stars. using the precipitation. elements like gold would accumulate at depths their densities dictate among other elements positions (like oil floating on water...etc...). at the time of the Earth's crust being formed just how much would meteors striking the planet at that period have affected the distribution of elements within the crust? or was the volcanic activity the greater influence for the distribution?

PS. thanks for the links.

 

[Bandersnatch]

Ah, o.k.
To answer you question, I think it's supposed to be all from meteors from after the crust solidified. What sunk earlier, sunk to the core of the planet, so volcanism can't be sensibly expected to drege it up.

 

[dragoneyes001]

yeah makes sense thank you.

 

[Bystander]

Principles of Geochemistry, Mason will give you an overview of cosmic, terrestrial, and crustal abundances and differentiation hypotheses.