Samples of rock harvested in Canada are thought to contain parts of Earth’s crust dating back to more than 4.3 billion years ago.
As Earth is estimated to be about 4.6 billion years old, researchers now say it’s possible that parts of our planet’s original crust still remain in place today.
Scientists found isotopic evidence of the ‘parent rocks’ of 2.7 billion-year-old samples from the Canadian Shield, suggesting Earth’s oldest crust survived the formation of this continental feature.
In a new study, researchers from the University of Ottawa and Carnegie Science analyzed the isotope ratios of samarium and neodymium rocks from the Superior Province, which sits just north of the Great Lakes.
These samples are composed primarily of a type of granite that’s 2.7 billion years old, and formed through the ‘recycling’ of older, magnesium-rich rocks.
‘This area of northern Quebec is the nucleus of the Canadian shield,’ explained Professor Jonathan O’Neil, of the university’s Department of Earth and Environmental Sciences.
‘Previous work had shown that if we had a flavour of something older, of this ancestor, it would be there.’