The Nuvvuactuq green belt of Canada is home to fragments of the oldest crust on the earth, shows the study
Geologists have discovered convincing evidence of the preservation of Hadean rocks – dating from 4.16 billion years – in a complex geological sequence called green stone belt Nuvvuactuq, opening a rare window on the early days of the earth.
The Greenstone Nuvvuactuq belt, Canada. Image credit: Jonathan O’Neil.
A large part of the first geological history of the earth remains poorly understood due to the scarcity of rocks and minerals of the Hadéan age (more than 4.03 billion years).
These ancient materials are generally modified or destroyed because the crust of the planet is recycled by current tectonic processes.
“A candidate to survive Crustal Rock from Hadean-Age is the Greenstone Nuvvuaguq belt,” said Dr. Christian Sole at the University of Ottawa and colleagues.
“However, this assertion is controversial; Some argue that the isotopic data underlying these estimates can rather reflect subsequent geological mixture processes rather than the real age of training. ”
“If it is demonstrated as an original Hadean, the green stone belt Nuvvuactuq would represent the oldest sequence of rocks preserved on earth.”
“It would offer critical information on the geology of the beginning of the earth, including the potential framework of the emergence of life.”
To force the age of the green stone belt Nuvvuactuq, the researchers focused on a specific type of old rocks – metagabbroic intrusions – in the belt.
These intrusions intersect with older basalt rocks, and this characteristic allowed the authors to use a dating combined with the uranium head (U-PB) with isotopic analyzes of Samarium-Neodymium (SM-ND) at short and long-lived to determine an age limit lower than older formations (older basalt rocks).
SM-ND data have given coherent ages of approximately 4.16 billion years, regardless of the location of the sample or the mineral composition.
The fact that the two isotopic systems produce the same age in rocks linked by clear evidence of magmatic differentiation strongly supports their crystallization of the Hadéan age.
This, in turn, argues the idea that fragments of the mafic crust of the Eon Hadean survived in the Greenstone Nuvvuactuq belt.
“Understanding these rocks returns to the very origins of our planet,” said Dr. Jonathan O’Neil, researcher at the University of Ottawa.
“This allows us to better understand how the first continents were formed and to rebuild the environment from which life could have emerged.”
The results were published in the journal Science.
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C. and al. 2025. Proof of mafic intrusions by Hadean in the green stone belt of Nuvvuactuq, Canada. Science 388 (6754): 1431-1435; Doi: 10.1126 / Science.ADS8461
