Scientists believe that the earth – and the rest of the solar system too – emerged from a cosmic gas cloud 5 billion to 6 billion years ago. About a billion years elapsed before the gas cloud cooled and condensed enough to allow the first minerals to crystallize.
These early rocks formed as a crust on the surface of the still hot and gaseous globe. Violent upheavals from deep within the earth melted and cracked the newly formed crust again and again, until enough heat had been released for the crust to solidify and form the land masses.
Until the discovery in Western Australia, evidence for the formation and appearance of the earliest rocks of earth has been incomplete: no rocks have been found that are old enough to provide proof of these early events. Therefore, scientists have had to look elsewhere for evidence of the age of the earth.
Read more: http://scienceray.com/earth-sciences/geology/the-oldest-rock-in-the-world-a-missing-link-in-a-billion-year-gap/#ixzz0zvToEYBT
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