CNN
–
A rocky outcrop on a far-off corner in northern Quebec looks calm in the eerie secluded quarantine on the eastern shore of Hudson Bay, Canada.
However, for the past 20 years, this exposed ancient seabed remains known as the Nuvvuagittuq Greenstone Belt has been a warm and scientific battlefield in its quest to identify the oldest rock on the planet.
New research suggests that geological sites have the oldest surviving fragments of Earth’s crust, dating back 4.16 billion years ago. It is the only rock from the beginning of four geological eons in the history of our planet. It began 4.6 billion years ago when the world was hot, turbulent, hellish.
“The Rock is a book for geologists… And now we’re missing the book (in Hadean). The Nuvvuagittuq Green Stone Belt is at least one page of that book, so that’s why it’s so important.”
The Nuvvuagittuq Greenstone belt has been dated several times by various research groups, with very different results. Most people agree that the rocks are at least 3.75 billion years old, but that is not the oldest on the planet.
It is more widely agreed that the Acasta Gneiss Complex, a group of exposed rocks along the riverbank 300km (300km) north of Yellowknife in northwestern Canada, is the oldest geological layer on Earth. These rocks were clearly dated 40.3 billion years ago, marking the boundary between Hadean Eon and the next chapter in Earth’s history, Archean. (There are old rocks on Earth, but not from Earth, and not part of this discussion. Some met stones are 4.5 billion years old.)
A controversial 2008 paper co-authored by O’Neil, who claimed he was a doctoral student and that Nuvvuagittuq Greenstone Belt was 4.3 billion years old, O’Neil is studying his Ph.D. However, other geologists had problems with the limitations of dating techniques and how data was interpreted. In this latest paper, O’Neill, currently an associate professor at the University of Ottawa in the Department of Global Environmental Sciences, aims to prove critics wrong.
Dating rocks involve using radiation techniques that exploit the natural and spontaneous radioactive attenuation of certain elements of the rock. This acts as a type of watch.
O’Neil uses the hourglass analogy. Imagine counting sand grains at the top (radioactive elements) and at the bottom (elements produced from radioactive decay). Knowing the velocity of flowing grain (represents the rate of decay) allows scientists to date rocks. Some of these radiant clocks are robust and can withstand the high temperatures and pressures that the Earth’s crust has withstanded in the year, while others are affected by these processes.
The gold standard and easiest way to make a very old rock layer is the extremely strict mineral known as zircon. These small crystals incorporate a little uranium into their structure, allowing researchers to identify age by measuring radioactive decay of uranium atoms, turning them into lead at known rates.
However, nuvvuagittuq green stone belt – Mapped after geological surveys in the 1960s, but attracted scientific attention in the early 2000s. It contains very few rocks with zircon, as they rarely occur in specimens with low levels of silicon, including the ancient oceanic crust.
“We tried to find the zircon. They were just not there or formed later during rock metamorphosis and cooking,” O’Neill said. Metamorphic rocks are those converted by heat, pressure, or other natural forces.
Instead, for new research, O’Neill turned to the rare earth element samarium, which collapsed into the elemental neodymium. The element was only active over 4 billion years ago, so it is a technique used to date a met stone.
“The controversy over this age is that some people believe that the clocks we use are not good or that it has been affected (by other geological processes),” he said.
“It’s a discussion about what we’re measuring in time because we can’t use zircon, and some people in my field will be sure of it only.”
O’Neill said this technique is worth it in this case. Because it is possible to measure the attenuation of two variants or isotopes of samarium on two different isotopes of neodymium, essentially you get two clocks for one price. The most recent paper focused on the fact that the two data points converged at the same age: 4.16 billion years ago, sampled from within the belt to an ancient rock of a certain type of metamorphicity – Metagabroic invasion.
This age means that Hadean Crust’s “at least a small debris” is preserved in the Nuvvuagittuq Greenstone belt, providing irreplaceable insight into the origins of the earth and how life was formed.
Nearby rocks from the same location may hold various life signatures from eon, and microfossils, small filaments formed by bacteria, tubes. He was not involved in the latest research, but is studying the fossils of the site.
“The newly-dated rocks come from a mantle that is not considered to be life-held or habitable for life,” said Papineau, professor emeritus of biogeochemistry and exobiology at Precambria at the University of London College.
“However, the adjacent sedimentary rocks are now confirmed to be at least 40,600,000 years old, which is “‘” about 400 million years after the addition of our planet and solar system,” he added in an email.
“The very early life evidence in these sedimentary rocks shows that the origin of life can be (relatively said) very quickly, which makes it more likely that life is common and widespread in the universe.”
According to other scientists who are not involved in the study, it is not yet clear whether the outcrop of Nuvvuagittuq will be widely accepted as the oldest rock on Earth.
Bernard Bourdon, a geochemist at the French Institute of Geology, Lyon, had previously had problems with the early dates of the Nuvvuagittuq Greenstone Belt published by O’Neill, but he said he was “more confident” by his latest work, and that he had “improved” in previous studies.
“The better thing compared to the 2008 paper is the fact that two techniques give us the same age. That’s good. That’s where we criticized the first results.”
“In the end, I think there’s more credibility in that era,” he said, adding that he has “minor questions” and wants to explore the data more deeply.
According to Hugo Oriek, a geoscientist and senior researcher at Curtin University in Australia, the Rock era remains “an unsolved mystery.”
“If there were no previous ‘easy’ minerals, they’ve turned into whole rocks. This is a problem because there are multiple minerals in the entire rock sample,” Oriek said in an email.
“One of these minerals will change and that age will just ‘reset’ the age for the whole House to fall,” he added.
Few things are critical when dealing with rocks and minerals with a complex geological history spanning over 4 billion years, according to Jesse Raymink, an early career professor of geoscience at Penn State University.
“It’s very surprising that even if these rocks were “small” 3.8 billion years ago, they’re still preserved. This current work presents more compelling data that supports an age 4.15 billion years ago than previously produced,” says Reimink.
“The timescale is very long and the history of these rocks and minerals is so tortured that it is very surprising to collect all the key information from them.”
Sign up CNN’s Wonder Theory Science Newsletter. Explore the universe with news about fascinating discoveries, scientific advancements and more.
