Editor's Summary
23 August 2007
Calibrating 'forever'?
Detrital zircons older than 4,000 million years from the Jack Hills, Western Australia are the oldest identified fragments of the Earth's crust, and are unique in preserving information on the earliest evolution of the Earth. Now micro-diamond inclusions have been discovered in Jack Hills zircon up to 4,252 million years old, including the oldest known diamonds found in terrestrial rocks. The spread of ages indicates that either conditions required for diamond formation were repeated several times during early Earth history, or that there was significant recycling of ancient diamond. Unless conditions on the early Earth were unique, the findings imply a relatively thick continental lithosphere and crust–mantle interaction at least 4,250 million years ago.
News and Views: Earth science: Old diamonds and the upper crust
Was the early Earth a blackened landscape of congealed lava, or was it cool enough for oceans to form? The discovery of diamonds in the oldest-known relics of surface rocks adds new élan to this debate.
Ian S. Williams
doi:10.1038/448880a
Letter: Hadean diamonds in zircon from Jack Hills, Western Australia
Martina Menneken, Alexander A. Nemchin, Thorsten Geisler, Robert T. Pidgeon & Simon A. Wilde
doi:10.1038/nature06083
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