The ‘world’s oldest water’ known to us was discovered in an ancient pool beneath Canada in 2016 and is at least 2 billion years old.
As early as 2013, scientists discovered the oldest water which is about 1.5 billion years ago at the Kidd Mine in Ontario, but in 2016, further investigation revealed that an older water source than Ontario’s was buried underground.
In 2013, this ancient liquid was first discovered at a depth of approximately 2.4 kilometers (1.5 miles) in an underground mine tunnel. But the depth of the mine, 3.1 kilometers (1.9 miles), the deepest base metal mine in the world, allows researchers to continue digging.
In 2016, Barbara Sherwood Lollar, a geochemist at the University of Toronto, told Rebecca Morelle on the BBC, “[The discovery in 2013] really delayed our understanding of the age of flowing water, so it really prompts us to explore more.”
“We take advantage of the fact that the mine continues to explore deeper earth.” The source was discovered about 3 kilometers (1.9 miles) away in 2016, and according to Sherwood Lollar, it’s much more than you think.
She said, “When people think of this water, they think it must be a small amount of water trapped in the rocks. But in fact, it is bubbling towards you. These things flow at a rate of liters per minute; the volume of water is much greater than anyone expected.”
Compared to surface water, the groundwater flow velocity is usually extremely slow, as low as 1 meter per year. But when drilling in a mine, its flow can reach about 2 liters per minute.
By analyzing dissolved gases in this ancient groundwater, including helium, neon, argon, and xenon, researchers were able to trace it for at least 2 billion years, making it the oldest water to be found on earth. The results of the study were announced at the Fall Meeting of the American Geophysical Union in San Francisco in December 2016.
An ancient pool below Canada in 2016 
The world’s oldest water to be found on Earth
In an earlier study published by the team in October, the analysis of sulfate content of this oldest water at 2.4 kilometers revealed something interesting about it – sulfate is produced in situ in a chemical reaction between water and rock. Instead of causing sulfate to be transported underground by surface water.
This means that the geochemical conditions in these ancient pools isolated from the surface are sufficient to support microbial life, an independent underground ecosystem that can last for billions of years.
“The surprise factor is high,” Long Li, a researcher at the University of Alberta, said in a news release.
“If geological processes can naturally provide stable energy to these rocks, the modern terrestrial underground biosphere can be significantly expanded in breadth and depth.”
This not only means that the potentially habitable area of the earth can be much larger, and considering that rocks with a history of one billion years represent about half of the earth’s continental crust; It can also mean that the habitability of planets on other planets may be more extensive than we thought.
“If this can work in ancient rocks on Earth, a similar process can make Mars habitable underground,” Sherwood Lollar explained to Hannah Fung at The Varsity in 2016.
Although we have not found any actual living microbial groundwater in this ancient place, on earth or elsewhere, the older the pools, the closer we get.
But there is still a lot of research to do. Sherwood Loral said,
“We still need to determine the distribution of ancient waters on earth, what is the age of this deep-water circle, and how many people live, What are the similarities or differences between any life we find in these isolated waters and other microbial life found in hydrothermal vents on the seafloor?”