Don’t drink it though.
Deep down within a Canadian mine researchers have made an incredible discovery: the world’s oldest known water. Found at a depth of roughly 3 kilometers (1.8 miles), it dates to an impressive 2 billion years old.
Back in 2013, the same research team discovered water dating back about 1.5 billion years, but this time they searched even deeper to reveal an even older pool buried underground. The new discovery pushes back the date for oldest water by at least 500 million years.
The Kidd Mine in Ontario, Canada, where the water was found, is the deepest basal metal mine in the world, as miners get deeper and deeper into the Earth’s crust in search of copper, zinc, and silver. When the new (well, old, old, old) water deposit was found, researchers analyzed it by studying the gases trapped inside. Water stuck in rock cracks often has gases like helium and xenon trapped, and by measuring these, scientists can tell how old the water actually is.
“When people think about this water they assume it must be some tiny amount of water trapped within the rock,” Professor Barbara Sherwood Lollar, who presented the discovery, told BBC News. “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.”
But the very old age of the water is not the only important discovery. When analyzing the liquid, the research team found traces of life in it! Although they haven’t found actual living bacteria as yet, what they did find is, in fact, the fingerprint of life, suggesting that there has been some form of microbiology living within the water for a very long time.
Previous analysis of the sulphate content of the 1.5-billion-year-old water found earlier at 2.4 km down showed that the sulphate present hadn’t been carried underground by surface water but was produced right there as the result of a chemical reaction between the water and the rock.
This means that the geochemical conditions in these ancient pools of water that are cut off from the surface could indeed be sufficient in themselves to sustain microbial life – independent, underground ecosystems that could potentially last for billions of years.
“The wow factor is high,” one of the researchers, Long Li from the University of Alberta, said in a press release.
“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.”
The fact that something has been able to survive, and even flourish, in water that is so old and so deep within the ground means that Earth’s potentially habitable areas just got a whole lot bigger – considering that comparable billion-year-old rocks make up about half of Earth’s continental crust. But it could also mean that planetary habitability on other worlds might be greater than we thought. While rivers no longer flow on the surface of Mars, there are still pockets of water and ice under the surface, which could provide the conditions necessary for life to thrive.
Sources: 1, 2, 3, 4