Oldest Water on Earth, 2.6 Billion Years Old Found; Geologist Confirms It Is Not Fit for Drinking
In 2013, geologists discovered a fracture deep in a Canadian mine containing Earth’s oldest water. Hidden almost 3 kilometres beneath the surface, the pristine groundwater has been sealed for about 2.64 billion years. The extraordinary find is located in a mine near Timmins, Ontario, a region geologically known as the Canadian Shield—the oldest part of North America’s crust. The site is ideal for studying ancient geology because its volcanic rock and sediment layers have remained undisturbed by erosion or seismic activity for billions of years.
An analysis of the water, published in Nature, reveals chemical composition indicating the water formed under ancient atmospheric conditions. To determine its age, researchers used advanced techniques based on noble gas analysis, especially xenon. Because noble gases are chemically inert and largely unreactive with other elements, they serve as extremely accurate time stamps. By analysing specific isotope ratios, scientists compared the “fingerprints” of the gases in the water with models of Earth’s atmospheric evolution.
Geologist and one of the study’s authors, Barbara Sherwood Lollar, professor at the University of Toronto’s Department of Earth Sciences, explained the validity of the findings. “Using water isotopes and, in particular, noble gases, we can quantify whether the water has any modern component. And none of it does, so it is indeed isolated from the modern water cycle,” Lollar said.
Early research showed the water was at least 1.5 billion years old. However, the gas content released from the surrounding rock indicates a much older age—2.6 billion years—precisely when those minerals first formed.
To give an idea, this water was trapped underground long before plants, animals, or even complex cells existed. At that time, Earth’s atmosphere contained little oxygen, and life was limited to simple single-celled organisms. Intriguingly, the ancient water contains chemicals known to support life. This suggests that microbial ecosystems could thrive without sunlight and be completely isolated from the outside atmosphere for millions of years. The finding strengthens the possibility of similar habitats elsewhere in the Solar System, such as beneath Mars’ surface, which could also have supported life.
Despite the significance, myths arose that the geologist drank Earth’s oldest water. Barbara Sherwood Lollar quickly clarified that the water is not drinkable because it tastes extremely bitter and is far saltier than seawater. “Unfortunately, the ‘and she drank it’ story is a media fabrication. I did not and would never do that. But if you have seen the video, you will have seen water flowing and bubbling in places. A few drops would probably get on you, and you would understand how bitter it must taste.” She added that the story arose when someone repeatedly asked whether the water could be drunk. She answered no because it would taste very terrible.