Oldest Rocks on Earth Discovered?

September 26, 2008

An expanse of bedrock along Hudson Bay, Canada, may be a chunk of crust that formed not long after the solar system was born nearly five billion years ago, according to a new study. The finding could push back the age of the most ancient remnant of stable crust on Earth by about 300 million years.

Previous research had dated rocks in northwestern Canada to 4.03 billion years ago, and tiny crystals of the mineral zircon in Western Australia are known to be upward of 4.38 billion years old.

It’s not known whether the bedrock itself is also as old as the crust, a question that awaits further analysis, said study co-author Richard Carlson, a geochemist at the Carnegie Institution in Washington, D.C.

Regardless, the ancient date supports the once-controversial idea that Earth was cool enough to produce crust early in its history.

Ancient rocks in the Nuvvuagittuq region of Hudson Bay, Canada (above), may be the oldest rocks known on Earth, scientists said in September 2008.
Image © Science/AAAS

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