The belt of green rocks of Nuvvuactuq has been known for its old rocks for a long time: gray plains of rocked rocks on the eastern shore of Hudson. However, researchers do not agree on their exact age.
Work carried out two decades ago suggested that rocks could have 4.3 billion years, thus located at the oldest era in the history of the earth. Other scientists, using a different dating method, however challenged this discovery, arguing that ancient contaminants failed the age of the rocks and that they were actually slightly younger, 3.8 billion years.
In this new study, the researchers sampered a different section of rock from the belt and estimated the age using the two previous dating techniques, which consist in measuring the disintegration of a radioactive element in another over time. Result: the rocks had around 4.16 billion years.
The different methods “have given exactly the same age,” said Jonathan O’Neil, author of the study and the University of Ottawa.
The new research was published Thursday in the journal Science.
The earth formed about 4.5 billion years ago from the collapse of a cloud of dust and gas, shortly after the appearance of the solar system. The primordial rocks are often melted and recycled by the movements of terrestrial tectonic plates, which makes them extremely rare on the surface today.
Scientists have discovered old-year-old rocks in another training in Canada, the Gneiss d’Acasta complex, in the Northwest Territories, but the rocks of Nuvvuactuq could be even older.
The study of the rocks of the beginnings of the history of the earth could give an overview of the appearance of the planet, in particular how its bubbling magma oceans gave way to tectonic plates and even how life appeared.
“Having a sample of what was going on on earth at that time is really precious,” said Mark Reagan, of the Iowa University, who studies volcanic rocks and lava and did not participate in the new study.
The rocky formation is on the tribal lands of Inukjuak and the local inuit community temporarily prohibited scientists from taking samples from the site due to the damage caused by previous visits.
After visiting geologists on the site, large pieces of rock lacked and the community noticed songs online, said Tommy Palliser, who manages the land with the Pituvik Landholding Corp. The Inuit community wishes to collaborate with scientists to create a provincial park that would protect the territory while allowing researchers to study it.
“There is a lot of interest in these rocks, and we understand it,” said Palliser, a member of the community. We just don’t want additional damage. ”
