Researchers date ancient water deep beneath earth’s surface
When a pocket of ancient water was discovered deep beneath the Earth in 2013, a team of Canadian researchers estimated it to be roughly 1.5 billion years old. At the same site, they discovered a deeper pocket of water estimated to be at least 2 billion years old, making it the oldest water on the planet.
Barbara Sherwood Lollar, a University of Toronto professor who led the team that discovered the original underground lake, told ABC News that the characteristics of this ancient water is very different from surface water:
It’s highly saline — another aspect of it that [which] tells us that this fluid has been in this sub-surface for really long time of period. […] So sometimes up to ten times the salinity of sea water, it’s really quite a nasty business really. […] To us it makes it much more interesting, it’s full of chemical energy for life, which is part of the reason why we’re investigating it.
She and other researchers discovered this water underground through exploration in the Kidd Creek Mine in Timmins, Ontario, Canada. The copper, zinc, and silver mine is one of the deepest, extending roughly 3.1 kilometers, or more than 10,000 feet, below the Earth’s surface. The earlier discovery was made at 2.4 kilometers, or close to 8,000 feet. This latest team looked specifically at fracture fluids drawn from 3 kilometers under the Earth’s surface. They used gas analysis to date the water.
The water in these underground pools flows slowly until tapped. When a borehole is drilled into the rock, the ancient water reportedly gushes out at rates of at least 2 liters per minute.
In a previous analysis, the team looked at the sulfate content of water found at 2.4 kilometers, and discovered the sulfate was produced through a chemical reaction between the water and the rock. It was not carried underground by surface water.
The researchers believe that conditions in these older waters could potentially sustain microbial life, and even be completely independent, self-sustaining ecosystems.
Water and Life
Understanding the deeper pockets of the Earth’s crust and the life within it helps increase our understanding of other planets and the possibilities for life forms that might exist below their surfaces, which are wholly separate from atmospheric conditions.
Sherwood Lollar explained:
For many years we still thought that life was really just a thin veneer on the surface of the planet, that life was largely dependent just on the sun’s energy. […] What we have learnt since then through work done at the hydrothermal vents, the ocean bottoms and caves and in the sub-surfaces, is in fact there is life on this planet as well in the deep dark places.
The next steps for the researchers include determining more information about the distribution and age of these pockets of underground water, whether they contain life forms, and if so, how they compare to microbial lifeforms found near hydrothermal vents on the ocean floors.
The latest work — “New Frontiers for Deep Fluids and Geobiology Research in the World’s Oldest Rocks” — was presented at the American Geophysical Union Fall meeting, December 12-16, 2016. The work has not yet been subjected to peer review.