Science and Space

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Early Earth has continents

A study of zircons, the oldest minerals on Earth, suggests that massive amounts of continental crust were formed soon after Earth’s creation 4.56 billion years ago.

Mark Harrison at the Australian National University in Canberra and his team looked at the ratio of hafnium isotopes, which change as a result of the radioactive decay of lutetium, to lutetium itself in 100 zircons dating back between 4 billion and 4.37 billion years. The minerals came from the Jack Hills in Western Australia.

Lutetium is retained in the melting Earth’s mantle, whereas hafnium becomes part of the continental crust. High hafnium ratios in the ancient zircon samples indicate that, at the time they were formed, much of the mantle had melted and cooled to produce crust

posted by: kyawoo at 21:12 | link | comments |
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