It’s been bubbling out of the rocks beneath their feet since the 1880s, but no one really appreciated the significance — until now.
An international research team reported Wednesday that miners near Timmins are tapping into an ancient underground oasis that may harbour prehistoric microbes. The water flowing out of fractures and bore holes in one mine near Timmins dates back more than a billion years, perhaps 2.6 billion, making it the oldest water known to exist on Earth, says the team that details the discovery in the journal Nature.
“This is the oldest (water) anybody has been able to pull out, and quite frankly, it changes the playing field,” says geologist Barbara Sherwood Lollar, at the University of Toronto, who co-led the team.
Her colleague Chris Ballentine at the University of Manchester in Britain describes it as an “ interconnected fluid system” deep in the Canadian Shield that is “billions of years old and capable of supporting life.”
The researchers have yet to find microbes living in the water, but Sherwood Lollar says the ancient fluids “certainly look habitable.” They expect to know for certain with in a year.
Meanwhile, the scientists say it’s time to rethink which parts of Earth — and planets like Mars — are fit for life.
“We are just slowly beginning to understand that in fact we are looking at a whole new hydrosphere on the planet,” Sherwood Lollar said in an interview. She said it appears several regions on Earth contain ancient isolated water in geological formations below the surface.
They are not underground lakes, she says, but more like veins of water that run through fractures in the rocks.
In 2006, Sherwood Lollar and her colleagues found microbes eking out an existence in saline waters 2.8 km below the surface in South African gold mines. That water had been cut off from the surface for tens of millions of years.
That work led the researchers to northern Ontario and the discovery of the much older water. It flows out of fractures and bore holes in a mine 2.4 kilometres below the surface. Sherwood Lollar declined to the name of the copper-zinc mine near Timmins involved in the project out of what she called “courtesy” to the company.
“The miners first tipped us to it,” says Sherwood Lollar, noting how records of “really saline water” in Canadian mines date back to the 1880s. “It had completely flown under the radar of the science community.”
The team collected samples of the water , which flows out of one fracture at the rate of almost two litres a minute, and took them back to the lab for analysis.
Analyses of isotopes of the compounds and gases in the samples revealed the salty water, which sparkles as ancient gas bubbles out of it, has been trapped in the rocks between 1.5 and 2.64 billion years. The water also contains plenty of hydrogen, comparable to rates found on hydrothermal vents in the deep ocean, which can fuel microbial life.
The rocks in the mines near Timmins were created by a massive hydrothermal vent system on an ancient seafloor 2.7 billion years ago. Volcanic lava and sea sediments are stacked up in the rocks like a “layer cake,” says Sherwood Lollar. “When you go down in the mines you can see some of the pillow lavas structures still preserved in the rock.”
People tend to think life on Earth first evolved “in a warm little pond” about 3.8 billion years ago, but she says another possibility is that life began below the surface, away from the meteorites and ultraviolet radiation bombarding the planet at the time.
“It is certainly plausible that life arose not in a warm little pond but a warm little fracture below the surface protected form what was going on at the surface,” she says. She and her colleagues speculate the same phenomena may be occurring below the surface of Mars, which has geology similar to the Canadian Shield.