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The reply to a question about nucleosynthesis, that heavier than iron elements are produced in supernovae explosions, raised for me the following question which I could not answer by googling. Partially because the search for planets and stars brings out astrology answers!

Explosions are dispersive, nevertheless we find minerals in clumps, not only uniformly dispersed in the ground. Is there a coherent presentation that explains how minerals end up in veins and bands?

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    $\begingroup$ It looks like this is due to geochemical processes, not astrophysical processes: en.wikipedia.org/wiki/Ore_genesis $\endgroup$ Mar 18, 2011 at 6:44
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    $\begingroup$ Is the question about Nucleosynthesis (the creation of heavy elements)? Or about the concentration of one or more elements via geochemical activities? $\endgroup$ Mar 18, 2011 at 14:30
  • $\begingroup$ I have found that the only suggestion for the appearance of heavy elements higher than Fe in the binding energy curve,comes from supernova explosions and scatterings of neutrons etc. So it is on the creation of heavy elements. Of course if veins and bands can come out from a uniform soup of elements by a reasonable model it would also explain the observations. $\endgroup$
    – anna v
    Mar 18, 2011 at 16:04
  • $\begingroup$ ""if veins and bands can come out from a uniform soup of elements by a reasonable model"" This model is called mineralogy and is very old and proven. $\endgroup$
    – Georg
    Mar 18, 2011 at 16:12
  • $\begingroup$ Hi Anna, I need help in some offline verification. would you be please available for a chat for 2 minutes, if so, please let me know when. I am in PST time zone. $\endgroup$
    – kpv
    Aug 25, 2016 at 5:46

3 Answers 3

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Mostly because they are heavy.

Rocks erode putting their constituents into solution, the heavy stuff settles out in river/sea beds, and metals are heavy.

For many metals hydrothermal process are more important. Super hot water deep in the earth dissolves the rock containing the minerals, it moves along cracks in the rock and cools depositing the salt and metals as lines in the rock.

In an asteroid with no geological process the metals are found in their raw state having cooled directly from the original ball of primeval gas

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    $\begingroup$ "the heavy stuff settles out in river/sea beds" - are you suggesting that veins can be essentially the "fossilized" remains of ancient stream beds? $\endgroup$
    – Michael
    Nov 25, 2014 at 3:34
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p.s. I have found a course notes precis and it seems there are several models proposed.

Completely out of my depth, I would propose that if matter above Fe in the binding energy curve were in a concentration within a "protoplanet" with a high enough pressure, it could form a quark gluon plasma, and then all type of nuclei could precipitate/crystalize as conditions change, according to their quantum mechanical state function, so a supernova explosion might be sufficient to make uranium, but not necessary. This would explain clumping and veins.

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    $\begingroup$ ""if matter below Fe were in a concentration within a protoplanet with a high enough pressure, it could form a quark gluon plasma,"" a quark-gluon-plasma does not even exist in the core of stars, how should that develop in a protoplanet? $\endgroup$
    – Georg
    Mar 18, 2011 at 12:44
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    $\begingroup$ I found this interesting diagram blogs.uslhc.us/the-quark-gluon-plasma . Also found the hypothesis that neutron stars are a quark gluon plasma. Maybe during the big bang when the temperature reaches the plasma stage heavier elements than those permitted to form by the binding energy curve are crystallized out en mass, clumping together. My objective is not to have a supernova as the only mechanism of creating the heavy elements, because explosions are dispersive. $\endgroup$
    – anna v
    Mar 18, 2011 at 15:58
  • $\begingroup$ ""My objective is not to have a supernova as the only mechanism of creating the heavy elements, because explosions are dispersive. "" But how will You get the transirons out of the neutron stars? Only after some dispersion there is a chance for the material to be incorporated in a planet. $\endgroup$
    – Georg
    Mar 18, 2011 at 16:09
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    $\begingroup$ you beat me to asking it, but roughly this question came to mind as i was lying in bed with my wife, and intuitively i reached this same conclusion. at that point, in bed, relaxed, it seemed extremely unlikely to me somehow that astro-snowballed uranium would just end up just so in planetary crust, due to the large number of collisions that would be required over time to 'snowball' large amounts of helium and hydrogen together into uranium and all the way into planetary crust in the backwaters of the universe, the local group, no less, just in time for it to keep decaying radioactively... $\endgroup$
    – ixtmixilix
    Feb 24, 2012 at 0:36
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Almost all the various "metals" (like primitive tribes that count "1, 2 many", the astronomers describe the elements as "hydrogen, helium, metals") in the earth come from supernovae explosions. So the uranium got there pretty much the same way that the silicon, iron, oxygen, potassium, etc.

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    $\begingroup$ In that case the uranium would be uniformally distributed every million atoms - and so rather tricky to find and mine. $\endgroup$ Apr 19, 2011 at 22:25
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    $\begingroup$ @Martin; Indeed, this is generally true. Per the wikipedia article: "Uranium is one of the more common elements in the Earth’s crust, some 40 times more common than silver and 500 times more common than gold.[1] It can be found almost everywhere in rock, soil, rivers, and oceans.[2] The challenge is to find those areas where the concentrations are adequate to form an economically viable deposit." $\endgroup$ Apr 19, 2011 at 22:53
  • $\begingroup$ Furthermore, having started college as a mining engineer, the concept that "the heavy stuff settles out in river/sea beds" is more or less true, but that "metals are heavy" has little to do with where uranium deposits appear. This is because uranium ores, while generally dense, are easily dissolved and are not sufficiently tough to appear as placer deposits. See the wikipedia article: en.wikipedia.org/wiki/Uranium_ore and look up information on placer deposits. $\endgroup$ Apr 19, 2011 at 22:55

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