Quebec Rocks May Be Oldest on Earth, Scientists Say

By KENNETH CHANG
Published: September 25, 2008

A swath of bedrock in northern Quebec may be the oldest known piece of the earth’s crust.

Researchers report that this rock is 4.28 billion years old and formed when the Earth was less than 300 million years old.
In an article appearing in Friday’s issue of the journal Science, scientists report that portions of that bedrock are 4.28 billion years old, formed when the earth was less than 300 million years old.

“These rocks paint this picture of an early earth that looked pretty much like the modern earth,” said Richard W. Carlson of the Carnegie Institution of Washington and one of the authors of the paper.

Other scientists are intrigued, but not yet entirely convinced that the rocks are quite that old.

“There is a certain amount of healthy skepticism that needs to play a role here,” said Stephen J. Mojzsis, a professor of geological sciences at the University of Colorado. Dr. Mojzsis said the new research was well done, but that he thought these were younger sedimentary rocks, pressed together out of the remnants of earlier rocks that were indeed 4.28 billion years old.

more:
http://www.nytimes.com/2008/09/26/science/26rock.html?ex=1380081600&en=df6a3b5b6f0c2342&ei=5124&partner=digg&exprod=digg

But it seems close enough to 4.5 billion years (most recent estimate of the moon's age that I've seen) that they might be about the same age.

If the collision theory origin of the moon is true, I've always wondered if there was any chance of solid rocks surviving from 'Earth Mark I' (or from whatever hit it).

The impact would of turned the surface into a sea of lava several hundred miles thick. The surface seems to have had solidified extremely quickly, though; there are 4.4 billion year old crystals of zircon (the hard, clear crystals used as fake diamonds) found in Australia that give chemical evidence of there being large bodies liquid water on Earth 4.4 billion years ago, just 100 million years after the great impact.

provide a first-person account and all that... :-)

The 4 billion year-old Actasca Formation in the NW Territories. :wow: