Saturday, 27th September 2008
Oldest rocks on earth found in northern Canada
A pinkish tract of bedrock on the eastern shore of Canada's Hudson Bay contains the oldest known rocks on earth, formed 4.28 billion years ago, not long after the planet was formed, scientists said on Thursday.
The rocks may be remnants of earth's primordial crust, which formed on the planet's surface as it cooled following the birth of the solar system, according to Jonathan O'Neil of McGill University in Montreal. "Maybe it was the original crust, and before that there was no stable crust on the earth. That's a big question," Dr O'Neil said in a telephone interview. The expanse in northern Quebec, measuring about 10 square kilometres, is made up of the volcanic rock basalt. To determine the age of the rocks, geochemists used isotopic dating methods analysing the elements samarium and neodymium.
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