How is Gold Formed Naturally?
Gold is a very valuable metal used in jewelry, computers, electronics, dentistry, and medicine. It has a fascinating origin story.
It can be formed naturally through several chemical and physical processes. One of these is the explosion of supernovae and the nuclear fusion that forms atoms of gold. Another is a collision of neutron stars, and a third is the formation of volcanic eruptions.
Supernovae
In a supernova explosion, or when neutron stars collide in collisions of stars known as neutron star mergers, the rapid neutron-capture process (r-process) and other nuclear processes can forge gold. They can also synthesize elements heavier than iron, such as copper and zinc.
These elements are not naturally produced in the Sun because they require a lot of energy to be forged. They can only be forged in energetic events, like massive stars exploding or neutron star collisions.
For millions of years, these energetic events have enriched the interstellar medium with heavy elements from hydrogen and helium. But the evolution of these elements still needs to be completed.
Neutron Star Collisions
If you’re a gold lover, you might wonder how this precious metal forms naturally. For centuries, astronomers have suspected that violent cosmic events such as supernovae could be responsible for minting elements heavier than iron – including gold.
But a new study suggests that the answer may lie in neutron star collisions. These are the smallest and densest stars in the universe, with masses bigger than our Sun’s.
When two neutron stars spiral into one another, they eject massive amounts of hot, dense matter. It then cools to less than 10 billion degrees and undergoes nuclear reactions to form heavy elements.
Erosion
Erosion is a geological process that transports materials from one place to another. It involves water, wind, or ice moving soil and rock.
In some places, erosion is more pronounced than in other parts of the planet. This is because the land may be bare, which makes it easy for the loose material to move off.
Gold is commonly found in gold ores and veins, deposits of fractured rock that the circulating of heated fluids has altered. These fluids pick up and concentrate gold and other minerals within the rocks.
Earthquakes
Earthquakes are caused by two pieces of rock, called tectonic plates, moving across each other. The edges of the plates bump into each other, causing friction. When the edges slip, they release energy and cause a lot of shaking.
The process can be very fast – sometimes, it can happen within a few tenths of a second. This happens along a network of fractures and jogs in the crust, known as faults.
A new study shows that sudden pressure drops trigger flash vaporization in these fluid-filled cracks, forming quartz veins and leaving behind gold as the minerals co-deposit with water. It’s a repeated process of building economic-grade gold deposits in regions where earthquakes occur regularly.
Volcanoes
Volcanoes are vents where lava, rock shards (tephra), and steam erupt onto the Earth’s surface. The eruption process can last days, months, or even years.
Molten rock is pushed upward by buoyancy and pressure from the magma, making it lighter than surrounding solid rock and allowing it to flow through cracks or gaps in the Earth’s crust. Sometimes, this is enough to break through weak areas in the Earth’s crust and begin an eruption.
Gold has been found in volcanic rocks and the ash thrown from volcanoes. This is because volcanic magma contains gold that floats to the surface.
