Geologist Discovers The World’s Oldest Water 2 Miles Below Earth’s Surface — Then She Tasted It

Geologist Barbara Sherwood Lollar has had a taste of a lot of rocks in her lifetime, mainly to figure out how old the water flowing in their fissures is. Between 2009 and 2013, she combed the rocks of Canada’s Kidd Creek Mine and discovered that the water locked inside was 1.5 billion years old. A few years later, as miners grinded deeper tunnels into the copper, zinc, and gold mines, she got an opportunity to dip her instruments a little deeper in this Canadian mine and pump out some samples of the deep underground water.

Laboratory analysis showed that the water was nearly 2.6 billion years old, becoming the “oldest water trapped in Earth’s crust.” That’s when Lollar did what she had always done. She dipped her finger in the water and licked it. Scrunching up her face at the musty smell, she described the water as “very salty and bitter – much saltier than seawater,” to CNN. After further investigation, Lollar and her team published their observations in the journal Nature. Rocks overhanging in the dark belly of Earth usually accumulate water when rain and snowmelt dribbles downwards due to gravity. The water settles in pools inside the clefts and grooves carved into the rocks, getting trapped underneath. 

“When people think about this water, they assume it must be some tiny amount of water trapped within the rock. 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,” Lollar told BBC. From previous studies, scientists already knew that there was old water hiding somewhere in the mines of Canada, South Africa, and Finland. But the exact location was unknown. Lollar, a geologist in the department of Earth Sciences at the University of Toronto, had been studying the Kidd Creek Mine in Timmins for over a decade. 

The Glencore-owned mine was known to be the deepest base metal mine below sea level, primarily with deposits of copper, zinc and silver. So when miners started digging the mines further down to extract more lucrative deposits, she and her team sensed the opportunity to have a taste of some ancient water trapped in a network of crevices in the underground granite rocks, about 1.5 miles beneath the Earth’s surface. “And we took advantage of the fact that the mine is continuing to explore deeper and deeper into the earth,” she told BBC. Adding to NBC News, she described that the team went down in cages as there were no elevators. Other times, they used ramps to delve down in a curling spiral roadways.

To deduce the age of this water, they studied the chemistry of the water bubbles, mainly the isotopes of noble gases such as helium. Speaking to CNN, Lollar revealed that these isotopes are the signature of the approximate age of water. Since the water beneath the mine remained isolated for over a billion years, the water slowly accumulated these noble gases. The chemical reactions occurring between these gases and the isotopes acted as the nutrition, paving way for little microbial communities to evolve and thrive.

The water from this Canadian mine was found to be teeming with microbial life. The discovery bemused scientists by offering them insights into how a microbial community could thrive similarly in an environment like that of Mars or other planets. "Finding life in this energy-rich water is especially exciting if one thinks of Mars, where there might be water of similar age and mineralogy under the surface. If any life once arose on Mars billions of years ago as it did on Earth, then it is likely in the subsurface. If we find the water in Timmins can support life, maybe the same might hold true for Mars as well,” Lollar told NBC News.