Oldest rocks on Earth 'discovered '
An international team has found the rocks, as old as 4.28 billion years, in Northern Quebec in Canada, along the Hudson's Bay coast, 40 km south in an area Nuvvuagittuq greenstone belt.world Updated: Sep 26, 2008 14:24 IST
Scientists have discovered the "oldest rocks" on Earth, a finding they claim could shed more light on our planet's mysterious beginnings.
An international team, led by University of McGill, has found the rocks, as old as 4.28 billion years, in Northern Quebec in Canada, along the Hudson's Bay coast, 40 km south of Inukjuak in an area known as the Nuvvuagittuq greenstone belt.
Earlier, the oldest-dated rocks were from a body of rock known as Acasta Gneiss in Canada's Northwest Territories which are 4.03 billion years old.
"Now, these (in Northern Qubec) are the oldest whole rocks found so far," lead scientist Richard W. Carlson said.
According to them, the rocks "faux-amphibolites" could be remnants of a portion of Earth's primordial crust -- that's the first crust which formed at the surface of our planet, the 'Science' journal reported.
The scientists estimated the age of the rocks using isotopic dating, which analyses the decay of the radioactive element neodymium-142 contained within them. This technique can only be used to date rocks 4.1 billion years old or older.
The Earth is 4.6 billion years old, and remnants of its early crust are extremely rare -- most of it has been mashed and recycled into Earth's interior several times over by plate tectonics since our planet formed.
"The data from these findings will give researchers a new window on the early separation of Earth's mantle from the crust in the Hadean Era. Our discovery not only opens the door to further unlock the secrets of the Earth's beginnings.
"Geologists now have a new playground to explore how and when life began, what the atmosphere may have looked like, and when the first continent formed," Jonathan O'Neil, a team member,said.