The ambiguous rock formations on the east coast of Hudson Bay in Canada may contain the oldest known rocks on Earth, new research claims.
This analysis took 4.16 billion years ago the striped gray rocks of the site, part of an outcrop called the Nuvvuagittuq Greenstone Belt.
Dating is carried out in two ways, measuring the age of ancient magma trapped in rocks using the decay of radioisotope (elemental versions), significantly enhancing controversial past research by the same scientists.
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If their discoveries, published in Journal Science on June 26th, rise up, they can provide a unique window into the geochemical stages in which ancient history of our planet and life emerged.
“Volcanal rocks must be at least 4.16 billion years old and I argue that the best age for them is 4.3 billion,” Jonathan O’Neill, professor of environmental science at the University of Ottawa, told Live Science. “The known rocks are not old.”
The Earth began as a ball of red hot lava. It cooled slowly over the first 600 million years as the solid lock pockets began to form. This was a tumultuous time for our young planet. This was repeatedly slapped by the asteroids, and even maintained a fierce blow from Protoplanet theology.
Related: Did plate tectonics cause life? Groundbreaking new research could crack the deepest mystery of the Earth
As early as 3.8 billion years ago, the surface of the Earth was either recycled inside the Earth or dived below each other to accumulate vast mountain ranges and ditches. This subduction means that much of the rocks on our planet’s surface have been chemically altered for a long time due to intense heat and pressure.
However, some areas are well far from the boundaries of the tectonic plates, as they contain rocks that have not changed for billions of years. One of these is in northeastern Canada, with the oldest part of which is the Nuvvuagittuq Green Stone Belt (NGB). Scientists agree that the outcrop is at least 3.8 billion years old.
Then, in 2008, O’Neill and his colleagues published a study suggesting that NGB was 4.3 billion years ago. This means that it contained the oldest rock in the world.
However, other geologists oppose it, suggesting that the researchers’ methods are flawed. Older rocks are usually dated using a mineral called zircon, which has been chemically stable for billions of years. However, NGB volcanic rocks do not contain zircon, and scientists were forced to measure the age of the rock to neodymium due to the collapse of the elemental samarium.
But this new way of trouble was lurking. Samarium decays to neodymium via two pathways (from samarium 146 to neodymium-142 or to neodymium 143 to samarium 147) creating two isotopic clocks with different decay rates. The first path of decay leads to a half-life of about 96 million years (the period required for half of the original elements to remain), while the second path has a half-life spanning trillions of years.
This means that the two damping paths produced highly different estimates for the age of the rock. This is because long-life clocks are etched in modern times and are particularly susceptible to structural events that disrupt isotopes along the way through the damping process.
The 4 billion-year-old “rocks and metamorphosis ‘cooking'” doesn’t really affect that short-lived clock, but it can reset the long-lived clock and cause an age difference between these two systems,” O’Neill said.
To avoid this issue, the team returned to the formation and searched for sections where magma from the Earth’s mantle or middle layer had invaded the planet’s primitive crust. These invasions could be used as the lowest age, as they had to be younger than the rocks they soaked in. A new analysis reveals within these sections of the NGB, both decays of neodymium provided 416 billion years, the same age.
Further research confirms that if the rocks are as old as O’Neill’s team believes, they can provide important insights into how life appeared on our planet and beyond.
“Some rocks from the Nuvvuagittuq Greenstone Belt were formed by precipitation from seawater. These help us understand our first ocean composition, temperature and atmosphere and host the oldest traces of life on Earth,” O’Neill said. “Understanding the environment in which life was able to begin on our planet can also help us explore finding traces of life elsewhere, such as Mars.”
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