Scientists from the University of Toronto have discovered an ancient pool of water in Glencore’s Kidd Mine in Timmins, Ontario that is at least 2 billion years old.
Science Alert reported that in 2013 a pond dating back 1.5 billion years was found but after searching deeper the second, older pond was discovered.
The initial discovery of the ancient liquid in 2013 came at a depth of around 2.4 km (1.5 miles) in an underground tunnel in the mine. But the extreme depth of the mine – which at 3.1 km (1.9 miles) is the deepest base metal mine in the world – gave researchers the opportunity to keep digging.
“[The 2013 find] really pushed back our understanding of how old flowing water could be and so it really drove us to explore further,” geochemist Barbara Sherwood Lollar from the University of Toronto told Rebecca Morelle at the BBC.
The Kidd Mine is the deepest base metal mine in the world and produces copper and zinc concentrates.
The new source of ancient water was found at about 3 km (1.9 miles) down, and according to Sherwood Lollar, there’s a significant amount.
“When people think about this water they assume it must be some tiny amount of water trapped within the rock,” Lollar said. “But in fact it’s very much bubbling right up out at you. These things are flowing at rates of litres per minute – the volume of the water is much larger than anyone anticipated.”
Ground water usually flows extremely slowly compared to surface water – as slowly as 1 m/a (3 ftpy). But when tapped with boreholes drilled in the mine, it can flow at about 2 l/min (6 ft/min).
By analysing gases dissolved in this ancient ground water – including helium, neon, argon and xenon – the researchers were able to date it back to at least 2 billion years, making it the oldest known water on Earth.
Science Alert reported that the findings were presented at the American Geophysical Union Fall Meeting in San Francisco, and have yet to be peer-reviewed. But if they can be independently verified, the implications could go far beyond just breaking geochemistry records.
In previous research that the team published in October, analysis of the sulfate content of the water found at 2.4 km (1.5 miles) down showed something interesting – that the sulfate was produced in situ in a chemical reaction between the water and the rock, and not the result of sulfate being carried underground by surface water.
This means that the geochemical conditions in these ancient pools of water that are cut off from the surface could be sufficient in themselves to sustain microbial life – an independent, underground ecosystem that could last for potentially billions of years.
Not only does that mean Earth’s potentially habitable areas just got a whole lot bigger – given comparable billion-year-old rocks make up about half of Earth's continental crust – it could also mean that planetary habitability on other worlds might be wider than we thought.