underground cavern filled with water
Sarah Biren
Sarah Biren
February 14, 2024 ·  3 min read

World’s Oldest Water Lies At The Bottom Of A Canadian Mine And Is 2 Billion Years Old

Researchers found the oldest water in the world. They discovered water dating to about 1.5 billion years at the Kidd Mine in Ontario, Canada. However, after further exploration, scientists from the University of Toronto discovered ancient underground water that is about 2 billion years old.

Researchers Find the Oldest Underground Water in the World

The research team presented their work at the American Geophysical Union Fall Meeting in San Francisco in 2016. Lead presenter Professor Barbara Sherwood Lollar said, “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 liters per minute; the volume of the water is much larger than anyone anticipated”. Keep in mind, that groundwater usually flows much more slowly compared to surface water. But with boreholes drilling through the ground, the water flow increases drastically. [1]

The first pool of old water was found 2.4km (1.5 miles) below in the Kidd Mine, which is known for copper, zinc, and silver. “It really pushed back our understanding of how old flowing water could be and so it really drove us to explore further,” said Prof. Sherwood Lollar. “And we took advantage of the fact that the mine is continuing to explore deeper and deeper into the earth.

Dr. Oliver Warr, from the University of Toronto, led the second investigation, which found the pool almost 3 km (1.9 miles) below in the mine. Tests on gases in this water — including helium, argon, xenon, and neon — determined the water to be at least two billion years old, the oldest on Earth. This discovery gave a new perspective on our planet and the world that had existed so long ago.

Read: Ancient Bronze Age Couple Found in Loving Embrace 3000 Years After Burial

Are the Sites Capable of Sustaining Life?

In the first pool 2.4km deep, researchers analyzed the sulfates in the water. They discovered that sulfates were created during a chemical reaction between the rock and the water, not incoming from surface water. In other words, these ancient waters — despite being cut off from the surface — might be capable of independently sustaining microbial life. “The wow factor is high,” said one of the researchers, Long Li from the University of Albert. “If geological processes can naturally supply a steady energy source in these rocks, the modern terrestrial subsurface biosphere may expand significantly both in breadth and depth.

This idea became more realized when the researchers found chemical traces of miniscule single-celled organisms that used to live in these old waters. “By looking at the sulfate in the water, we were able to see a fingerprint that’s indicative of the presence of life,” said Prof. Sherwood Lollar. “And we were able to indicate that the signal we are seeing in the fluids has to have been produced by microbiology. And most importantly, has to have been produced over a very long time scale. The microbes that produced this signature couldn’t have done it overnight. This isn’t just a signature of very modern microbiology. This has to be an indication that organisms have been present in these fluids on a geological timescale.[2]

Life on Other Planets?

This means the Earth may be able to sustain life in more areas than originally thought. Not only that, but more studies on ancient waters can reveal where life might exist somewhere else in the solar system. Like in the icy oceans on the moon of Jupiter and Saturn perhaps. However, scientists have yet to find actually living microbes in these ancient pools. But finding more sites like these increases the chances of finding a real self-sustaining ecosystem.

We still need to determine what the distribution of ancient waters are on Earth, what the ages of this deep hydrogeosphere are, how many are inhabited,” said Prof. Sherwood Lollar. “[A]nd how any life we might find in those isolated waters is the same or different from other microbial life found for instance at the hydrothermal vents on the ocean floors.[3]

Keep Reading: An 82-year-old engineer made a machine that can turn air into drinking water


  1. “World’s Oldest Water Lies At The Bottom Of A Canadian Mine And Is 2 Billion Years Old.” IFL Science. Josh Davis. July 5, 2022
  2. “World’s oldest water gets even older.BBC News. Rebecca Morelle. December 14, 2016
  3. “The World’s Oldest Water Is Even More Ancient Than We Realised.Science Alert. Peter Dockrill. December 15, 2016