The gold comes from meteorites

September 8, 2011
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Researchers at the University of Bristol, UK, reported that after a high-precision analysis on some of the oldest rock samples from Earth provides clear evidence that the world accessible supplies of precious metals are the result of meteorite bombardment that took place 200 million years after the formation of Earth. This research was published in Nature.

When the Earth was formed, cast iron sank to the center forming the core. This phenomenon has carried the vast majority of our planet’s precious metals like gold and platinum. In fact, there are enough precious metals in the Earth’s core to cover the entire planet’s surface with a layer of four meters thick.

Dr. Matthias Willbold and Professor Tim Elliott of Bristol Isotope Group of Earth Sciences School revealed that they analyzed Greenland rocks formed almost four billion years, collected by Professor Stephen Moorbath, University of Oxford. These ancient rocks provide a unique window into the composition of our planet soon after the formation of the nucleus, but before the bombardment of meteorites.

Meteor impact at the time, shake the mantle of the Earth by giant convection processes. A goal for future work is to study the duration of this process. Subsequently, the geological processes formed the continents and concentrates of precious metals (and tungsten) in deposits of minerals that are mined today.

“Our work shows that most of the precious metals, key to our economies and many industrial processes, came to our planet by a fortunate coincidence, when the Earth was hit by the asteroid material,” experts said.