World’s Oldest Rocks Confirmed in Canada
Rocks in Canada are confirmed as the oldest in the world
In 2008, scientists reported that rocks in Canada were the oldest in the world. The new data seems to confirm this disputed complaint
An artistic impression of the earth during the Eon Hadean, when the planet formed its first solid crust – most of which sink into the coat later to never be revised again.
On the banks of Hudson’s Bay in northeast Canada, which could be the oldest rocks in the world. A study now suggests that they have at least 4.16 billion years – 160 million years more than all the others recorded, and the only piece of crust of the earth known for having survived the first eon of the planet.
In 2008, the researchers indicated that these rocks dated up to 4.3 billion years, an assertion that other scientists have challenged. Work reported today in Science1 It seems to confirm that the rocks, known as the Greenstone Nuvvuactuq belt, are record breakers.
The researchers say that the rocky formation offers a unique window on the start of the earth, after the planet has cooled up since its fiery birth 4.5 billion years ago.
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“It is not a question of” my rock is older than yours “,” explains Jonathan O’Neil, geologist at the University of Ottawa who heads the research team. “It’s just that it is a unique opportunity to understand what was going on during this period.”
The label of “oldest rocks” sometimes turned against him. In recent years, other teams have waved numerous samples of the Nuvvuactuq belt, leaving the landscape marked. Last year, the local Inuit community closed access to the rocks to avoid more despair.
Only a handful of geological samples in the world dates back 3.8 billion years or more. Among these, the oldest rocks are in the formation of Acasta Gneiss in the territories of northwestern Canada; At 4 billion years, they mark the border between the first geological eon of the earth, the Hadean, and the next, the Archaean. Geologists have also found tiny mineral crystals dating from the Hadee – such as zircon crystals of $ 4.4 billion in Western Australia – which have become anchored in the more recent rock. But there are no pieces of survivor crust known to the Hadean – except, perhaps, the Greenstone Nuvvuactuq belt. It consists mainly of materials which began as volcanic basalt before undergoing various modifications during the tortured history of the earth.
The green belt of the Nuvvuactuq of Canada in Canada could have come from the basalt lava of a volcano that broke out about 4.3 billion years ago.
In their 2008 work, O’Neil and his colleagues analyzed the chemical footprint left by the radioactive decay of the Samarium-146 isotope in the neodymium-142 to calculate that the Nuvvuactuq rocks were 4.3 billion years. (Samarium-146 is a short-term isotope that was exhausted in the first 500 million years of the earth, and none was left after about 4 billion years.) Other scientists challenged this work, arguing, for example, that the Hadéan age crust had become mixed in a younger crust, contaminating the results.
For the latest works, the O’Neil team analyzed rocks once molonaires which had been intrusive in the main rocks of Nuvvuaguq as a knife cutting in a cake. Going out with intruding rocks, O’Neil and his colleagues were able to establish a minimum age for the cake itself. They used two radioactive clocks: the disintegration of Samarium-146 in the neodymium-142 and that of Samarium-147 in the neodymium-43. The two gave ages of about 4.16 billion years for the intruda rocks. “If you do not agree with this, you need a very speculative and complex model to get the same answer,” explains O’Neil.
Having the two clocks of agreement on an age – which was not the case in previous work – strengthens the case for a Hadean age for the rocks, explains Bernard Bourdon, geochemist at the University of Lyon in France. He remains circumspect, however, and says he would like to see additional evidence, involving other disintegrations of radioactive isotopes. “I would be happy if these rocks were really Hadian, but I think we must still be careful,” explains Bourdon.
The document “provides a new set of data which, hopefully, can advance this discussion,” explains Richard Carlson, geochemist at Carnegie Science in Washington DC who collaborated with O’Neil in previous works. For Carlson, most of the evidence suggests that the rocks are indeed Hadean.
For the moment, more answers may have to wait. The Pluvik Landholding Corporation in Inukjuak, Canada – The Inuit group which is intendant of the field in question – currently does not grant a permit for an additional scientific study, due to previous damage to other groups. “It’s unfortunate, but I would do the same,” says O’Neil.
This article is reproduced with permission and was first publication June 26, 2025.
