A pair of geologists from the University of Ottawa (Ontario, Canada) and the Carnegie Institute for Science (Washington, D.C.) made a stunning discovery in the Canadian area known as Hudson Bay.
While exploring the eastern shore of Northwestern Quebec, the scientists came upon a piece of ancient granite, encasing volcanic rock that is believed to have survived the Earth's cooling process and belong to our planet's early crust, formed roughly 4.3 billion years ago.
This incredible find is all the more astonishing considering most of the planetary crust has been long destroyed through the subduction of tectonic plates, the earliest surviving piece previously discovered dating back just 2.7 million years.
This makes the volcanic rock that emerged in Hudson Bay the oldest geological treasure ever uncovered.
"I think that it's a piece of the original crust. It was cooked, but I think it's still very close to what it used to be," said team leader Jonathan O'Neil, from the University of Ottawa, in a statement.
Together with Richard Carlson, the pair published their conclusions in the journal Science and believes their finding could shed new light into our planet's early geodynamics, leading to a more comprehensive understanding of how planets are formed in our solar system.
Cutting-Edge Isotope Technology Reveals Rock's Age
The 4.3-billion-year-old rock, which is a basalt believed to have come from underneath the Earth's first oceans, was recovered from the continent's ancient geological core, a region called "The Canadian Shield."
The scientists were able to trace back the rock's age by using the latest geological technique, developed only a decade ago and available in just a few geology labs.
This technique enabled O'Neil and his research partner, Carlson, of the Carnegie Institute for Science, to measure the rock's composition and analyze the decay of a rare isotope called samarium-146, which was only produced on Earth during the planet's first 500 million years of existence, when the cooling process gave birth to the planetary crust.
Terra Primum
The team examined the basalt rock, as well as the granite cocoon it was found in, and discovered both of them had ancient origins.
The study revealed the granite formation to be just one geological step away from Earth's original crust. The scientists believe this old granite was formed when the planet's early crust was recycled back into the mantle, 1.3 billion years after it appeared on the surface.
The piece of basalt, however, proved to be even older. The team was astonished to discover it belonged to the original crust itself — terra primum, formed between 4.2 billion and 4.3 billion years ago — and managed to survive the planet's violent evolutionary processes, perfectly preserved in its granite encasing.
"By studying the makeup of these rocks, you almost piece together the DNA, so to speak, of these old continents," said O'Neil.
