The precious metal gold may not be native to earth but have come from outer space and merged in the core. The geologists at the University of Bristol have put forth a theory that a mammoth meteorite shower over four billion years ago is what brought the precious metals gold and platinum to earth.
They believe that the large deposits of gold and related precious metals came to the earth in meteorites after the core of the planet was formed by molten iron sanking into the core center. The staggering 20 quintillion tonnes of meteorite matter crashed into the earth in a shower about 200 million years ago and this ore is what is being mined today.
Dr Matthias Willbold , who led the research team at the university of Bristol said that their work showed that most of the precious metals on which our economies and many key industrial processes are based have been added to our planet by lucky coincidence when the Earth was hit by about 20 billion tonnes of asteroidal material.
The earth’s crust and mantel have more gold and precious metals than expected in a model of planetary formation. This means that the gold and precious metals came in at a later stage of the formation of the planet. Dr Willbold added that the proportions of gold and other precious metals are difficult to measure because they concentrate into nuggets, and they need to analyse a lot of rocks to get meaningful data.
The team members have been studying old rocks in Greenland to see just how the planet had changed over time. The analysis of these ancient rocks showed that they were formed during the earth’s formation and had higher ratio of the tungsten isotope 182W when compared to more modern rocks. Thus the modern rocks must have come to earth through a meteorite shower.