Ancient diamonds provide clues on Earth history

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Ancient diamonds unlock secrets of early Earth<br />Wed Aug 22, 2007 3:43PM EDT<br />By Ben Hirschler<br /><br />LONDON (Reuters) - Diamonds more than 4 billion years old -- nearly as old as the Earth itself -- have been discovered in Western Australia, giving scientists vital clues about the early history of our planet.<br /><br />Found trapped in zircon crystals in the Jack Hills region, the small gems are the oldest identified fragments of the Earth's crust and their existence suggests the Earth may have cooled faster than previously thought, experts said on Wednesday.<br /><br />The time between the creation of the Earth around 4.5 billion years ago and the formation of the oldest known rocks some 500 million years later is known as the Hadean period -- the "dark ages" of geology.<br /><br />Many geologists have traditionally thought of it as a time when the surface of the planet was a mass of molten lava. But the discovery of the ancient diamonds, reported in the journal Nature, challenges that view.<br /><br />Martina Menneken of Westfalische Wilhelms-Universitat Muenster, Germany, and colleagues said the presence of diamonds -- which are created under intense pressure -- implied there was a relatively thick continental crust as early as 4.25 billion years ago.<br /><br />This suggests it may have taken only around 200 million years for the Earth's surface to cool enough for water to condense and oceans to form.<br /><br />"These latest findings indicate that the planet was already cooling and forming a crust much earlier than previously thought," Alexander Nemchin, an expert in geochemistry at Australia's Curtin University of Technology and one of Menneken's co-researchers, said in a statement.<br /><br />"Jack Hills is the only place on Earth that can give us this kind of information about the formation of the Earth. We're dealing with the oldest material on the planet."<br /><br />Radioactive dating showed the crystals from Western Australia varied in age from 3.06 billion to

 

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Wow, this is absolutely fascinating stuff.<br /><br />Certainly the Earth's crust formed far quicker than originally thought.<br /><br />I wonder if liquid water on Earth formed at an earlier time too.<br /><br />General idea had it that the Earth's crust re-melted when the iron seperated out to <br />form the Cores (inner & outer).<br /><br />Perhaps this did not happen & our planet differentiated whilst it formed??<br /><br />Andrew Brown. <div class="Discussion_UserSignature"> <p><font color="#000080">"I suddenly noticed an anomaly to the left of Io, just off the rim of that world. It was extremely large with respect to the overall size of Io and crescent shaped. It seemed unbelievable that something that big had not been visible before".</font> <em><strong><font color="#000000">Linda Morabito </font></strong><font color="#800000">on discovering that the Jupiter moon Io was volcanically active. Friday 9th March 1979.</font></em></p><p><font size="1" color="#000080">http://www.launchphotography.com/</font><br /><br /><font size="1" color="#000080">http://anthmartian.googlepages.com/thisislandearth</font></p><p><font size="1" color="#000080">http://web.me.com/meridianijournal</font></p> </div>