The oldest known water in the world was discovered in an ancient basin below Canada in 2016 and is at least 2 billion years old.
As early as 2013, scientists discovered water about 1.5 billion years old in the Kidd mine in Ontario, but in 2016, more in-depth investigations revealed an even older source buried underground.
The initial discovery of the ancient liquid in 2013 was at a depth of about 2.4 kilometers (1.5 miles) in an underground tunnel in the mine. But the mine’s extreme depth – 3.1 kilometers, the world’s deepest base mine – has allowed researchers to continue digging.
“[The 2013 find] it really repulsed our understanding of how old running water can be, and so it really prompted us to explore further, “said Barbara Sherwood Lolar, a geochemist at the University of Toronto, to Rebecca Morel at the BBC in 201
“And we took advantage of the fact that the mine continues to explore deeper and deeper into the ground.”
The source from 2016 was found about 3 kilometers (1.9 miles) down and according to Sherwood Lolar there is much more of it than you might expect.
“When people think of this water, they suggest that it must be some small amount of water caught in the rock,” she said.
“But they actually explode a lot on you. These things flow at a rate of liters per minute – the volume of water is much larger than anyone expected.”
Groundwater is usually extremely slow compared to surface water – as slow as 1 meter per year. But when tapped with boreholes drilled in the mine, it can flow at about 2 liters per minute.
By analyzing gases dissolved in this ancient groundwater – including helium, neon, argon and xenon – researchers have been able to date it to at least 2 billion years, making it the oldest known water on Earth.
The findings were presented in December 2016 at the fall meeting of the American Geophysical Union in San Francisco.
In previous studies published by the team in October, the analysis of the sulphate content of the water found 2.4 km below showed something interesting – that sulphate was produced on the spot in a chemical reaction between water and rock, not as a result of the transfer of sulphate underground from surface waters.
This means that the geochemical conditions in these ancient bodies of water, which are detached from the surface, may in themselves be sufficient to sustain microbial life – an independent, underground ecosystem that could potentially last for billions of years.
“The wow factor is high,” one Long University researcher at the University of Alberta said in a press release.
“If geological processes can naturally provide a stable source of energy in these rocks, the modern terrestrial underground biosphere can expand significantly in both latitude and depth.”
Not only does this mean that potentially habitable areas of the Earth can be much larger – given the comparable billions of years of rocks that make up about half of the Earth’s continental crust – it can also mean that the habitability of planets in other worlds it may be wider than we thought.
“If this can work on ancient rocks on Earth, then such processes can make the subterranean surface of Mars habitable,” Sherwood Lolar told Hannah Fung in Varsity back in 2016
Although we have not yet found any real living microbes in this ancient groundwater – on Earth or anywhere else – the more ancient pools we discover, the closer we can get.
But much more needs to be done.
“We still have to determine the distribution of the ancient waters of the Earth, the age of this deep hydrogeosphere, how many are inhabited,” Sherwood Lolar said.
“[A]and how any life we might find in these isolated waters is the same or different from the other microbial life found, for example, in the hydrothermal vents on the ocean floor. “
A version of this article was first published in December 2016.