Why does gold run in veins? All heavy metals like this come from supernovas. Why would they concentrate in some position when they eventually make it to Earth?


Why does gold run in veins? All heavy metals like this come from supernovas. Why would they concentrate in some position when they eventually make it to Earth?

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As I understand it, at a given heat and temperature, minerals become dissolved/melted and as they flow cool and condense at certain points and you wind up with concentrations. Gold may be a little more involved, since it’s fairly inert, but this is how you get veins of crystals and the like.

It’s not like gold is formed in a supernova or some other celestial process and then slowly makes its way to an already existing Earth. What happens is that billions and billions and billions of years ago, certain elements were formed in supernova and widely dispersed. These elements ended up intermixed in giant clouds of mostly hydrogen gas, which coalesced into a rotating disk of matter, which further coalesced into our sun at its center and lots of dust and small rocky objects orbiting what would become the sun. Over millennia, the smaller rocky objects, some of which contained gold, coalesced into larger and larger objects. The heat of the collisions of these bodies melted them, and heavier elements tended to clumped together, and some of it sunk toward the interior of the molten ball of Rock. Plate tectonics, subduction, and volcanism, provided ongoing mixing and melting of these materials. Gold tended to clump together since it was denser than most of the surrounding materials, and as it cooled, it did so in clumps, or veins. In mountain forming regions, these veins and the surrounding rock was pushed up into the spots we find it today. This is an ongoing process, but it happens on geological time scales.

/edited for typos

They don’t “make it to Earth” from Supernovae. The molecules are created there yes, but they coalesced as Earth was forming, where they would have clumped together amongst the other dust (and eventually rocks) which ended up forming the planet.

[Gold veins form instantly during earthquakes.](https://www.nature.com/news/earthquakes-make-gold-veins-in-an-instant-1.12615) Gold isn’t water soluble except in *incredibly* strong acids, on the surface of the Earth. But deep underground, at extremely high pressure, it can dissolve much more easily. The most current theory is that during earthquakes, the pressure is relieved and the gold solidifies instantly in pure form.

More generally, gold is concentrated by the process of water and light minerals being carried underground by plate tectonics, and bubbling to the surface. Gold is not chemically reactive, so it is rarely concentrated like that. Platinum and rare earth elements are even less strongly concentrated by geochemical processes.

The elements start mixed throughout the planet. But after that there are various forces working on the elements. Each whenever or mineral responds differently to these conditions.

A simple one is density. Denser materials will slowly settle to lower positions over time. This is why Earths court is highly concentrated iron, nickle and heavy elements.

There is also melting points, and how easily it dissolves into water. Having different behaviors for each of these means gold might transport through the rock carried by water, but then settle out while other materials stay dissolved and moving.