Large veins of gold can take hundreds of thousands of years to form. But there are deposits of great wealth that are beyond the norm. They can form in just a few years, months, or even days! This has puzzled scientists for a long time. How is it possible that they form so quickly? Where does the gold come from that is formed in a few days?
Anthony Williams-Jones and Duncan McLeish from McGill University studied it. They checked examples of these deposits in different mines. They found that they form in a similar way to sour milk. Their results are collected in an article published this week. Named Colloidal transport and flocculation are the cause of the over-enrichment of gold in nature.
Gold deposits occur when hot water flows through rocks. It dissolves tiny amounts of gold and concentrates it in the cracks in the earth’s crust. It happens on levels that are invisible to the naked eye. In so-called bonanza deposits, the concentration of these gold veins is millions of times higher than the usual gold concentration in the earth’s crust. That is why they are so popular. How can fluids with such low gold concentrations lead to these abundant gold deposits?
“Our results solve this paradox,” explain the scientists. ‘These gold deposits shouldn’t exist. There just wasn’t enough time for her to form. And yet they exist!
The gold concentration in hot water is very low. It would take millions of years to fill a one-inch-wide crack with gold. What about the gold that is formed in just a few days?
Gold and milk
‘We use a powerful electron microscope. Bonanza gold deposits are formed from a liquid that is very similar to milk. ‘Milk is made up of tiny fat particles. When cutting, they hang in the water because they repel each other. A surface film in the form of a kind of gelatine is created. ‘The same is true of colloids of gold. They are formed by charged gold nanoparticles that repel each other. When they lose their charge, they decompose and flocculate. This type of jelly gets trapped in the crevices in the rock. And the ultra-high gold veins are formed.
“It is the first evidence of the formation and flocculation of a colloid of gold in nature. We can develop more effective strategies for researching them, ”the authors explain.
The modern gold hunters, the great miners, have an extra tool to help them find it.