The ancient water was collected from
boreholes at Timmins Mine beneath Ontario,
Canada, at a depth of about 1.5 miles (2.4
kilometers).
"When these rocks formed, this part of
Canada was the ocean floor," said study co-
author Barbara Sherwood Lollar, an Earth
scientist at Canada's University of Toronto.
"When we go down [into the mine] with
students, we like to say imagine you're
walking on the seafloor 2.6 billion years
ago."
Working with U.K. colleagues Chris
Ballentine and Greg Holland, Sherwood
Lollar and her team found that the water
was rich in dissolved gases such as hydrogen
and methane, which could provide energy
for microbes like those found around
hydrothermal vents in the deep ocean.
In addition, the water contained different
rare gases that include the elements helium,
neon, argon, and xenon, which were created
through interactions with the surrounding
radioactive rock. By measuring the
concentrations of isotopes of these "noble
gases"—so called because they rarely interact
with other elements—the team could
estimate how long the water had been
trapped underground and whether it had
been isolated.
Depending on the noble gas analyzed, the
age estimates for the water varied between
1.1 billion years old and 2.6 billion years old
—or as old as the rocks in the mine itself.
"It shows us that there's been very little
mixing between this water and the surface
water," Sherwood Lollar said. "What we
want to do with further work is see if we can
narrow that [age range] down."
Teeming With Life?
Geologists have long known that a lot of
water can be present in continental crust,
locked away in microscopic voids in
minerals, pore spaces between minerals, and
veins and fractures in the rock. But what's
been unclear is the age of such water, said
geochemist Steven Shirey, a senior scientist
at the Carnegie Institution for Science.
"The question is how old is it? Is it water
that's part of current circulation with surface
water? Or is it water that retains old
chemistry and potential biota?" said Shirey,
who was not involved in the study.
The new findings, detailed in this week's
issue of the journal Nature, is evidence that
ancient pockets of water can remain isolated
in the Earth's crust for billions of years.
"That's the really exciting part about this
study," Shirey said.
Sherwood Lollar and her team are testing the
mine water to see if they can find evidence
of living microbes. If life does exist in the
water, she said, it could be similar to
microbes previously found in far younger
water flowing from a mine located 1.74 miles
(2.8 kilometers) beneath South Africa.
Those microbes could survive without light
from the sun, subsisting instead on chemicals
created through the interactions between
water and rock.
Such "buried" microbial communities are
rare, and fascinating for scientists because
they are often not interconnected.
"Each one of them may have a different age
and a different history," Sherwood Lollar
said. "It will be fascinating for us to look at
the microbiology in each of them ... It'll tell
us something about the evolution of life and
the colonization of the subsurface."
Expanding Horizons
The Timmins Mine water could also help
scientists understand how much of the
subsurface of the Earth is actually inhabited
by life. The answer to that question has
implications for life on other planets, such as
Mars, scientists say.
"It opens up your horizons for what's
possible," Shirey said. "If you think that you
can have microbial life throughout the entire
crust of the Earth, then all of a sudden it
becomes very possible that life could live on
other planets under the right condition."
That raises questions about potential life in
relatively warm rock located beneath the
cold surface of Mars, where liquid water
could still exist.
"We're looking at billion-year-old rock here
and we can still find flowing water that's full
of the kind of energy that can support life,"
Sherwood Lollar said.
"If we find Martian rocks of the same age
and in places of similar geology and
mineralogy to our site, then there's every
reason to think that we might be able to find
the same thing in the deep subsurface of
Mars."
boreholes at Timmins Mine beneath Ontario,
Canada, at a depth of about 1.5 miles (2.4
kilometers).
"When these rocks formed, this part of
Canada was the ocean floor," said study co-
author Barbara Sherwood Lollar, an Earth
scientist at Canada's University of Toronto.
"When we go down [into the mine] with
students, we like to say imagine you're
walking on the seafloor 2.6 billion years
ago."
Working with U.K. colleagues Chris
Ballentine and Greg Holland, Sherwood
Lollar and her team found that the water
was rich in dissolved gases such as hydrogen
and methane, which could provide energy
for microbes like those found around
hydrothermal vents in the deep ocean.
In addition, the water contained different
rare gases that include the elements helium,
neon, argon, and xenon, which were created
through interactions with the surrounding
radioactive rock. By measuring the
concentrations of isotopes of these "noble
gases"—so called because they rarely interact
with other elements—the team could
estimate how long the water had been
trapped underground and whether it had
been isolated.
Depending on the noble gas analyzed, the
age estimates for the water varied between
1.1 billion years old and 2.6 billion years old
—or as old as the rocks in the mine itself.
"It shows us that there's been very little
mixing between this water and the surface
water," Sherwood Lollar said. "What we
want to do with further work is see if we can
narrow that [age range] down."
Teeming With Life?
Geologists have long known that a lot of
water can be present in continental crust,
locked away in microscopic voids in
minerals, pore spaces between minerals, and
veins and fractures in the rock. But what's
been unclear is the age of such water, said
geochemist Steven Shirey, a senior scientist
at the Carnegie Institution for Science.
"The question is how old is it? Is it water
that's part of current circulation with surface
water? Or is it water that retains old
chemistry and potential biota?" said Shirey,
who was not involved in the study.
The new findings, detailed in this week's
issue of the journal Nature, is evidence that
ancient pockets of water can remain isolated
in the Earth's crust for billions of years.
"That's the really exciting part about this
study," Shirey said.
Sherwood Lollar and her team are testing the
mine water to see if they can find evidence
of living microbes. If life does exist in the
water, she said, it could be similar to
microbes previously found in far younger
water flowing from a mine located 1.74 miles
(2.8 kilometers) beneath South Africa.
Those microbes could survive without light
from the sun, subsisting instead on chemicals
created through the interactions between
water and rock.
Such "buried" microbial communities are
rare, and fascinating for scientists because
they are often not interconnected.
"Each one of them may have a different age
and a different history," Sherwood Lollar
said. "It will be fascinating for us to look at
the microbiology in each of them ... It'll tell
us something about the evolution of life and
the colonization of the subsurface."
Expanding Horizons
The Timmins Mine water could also help
scientists understand how much of the
subsurface of the Earth is actually inhabited
by life. The answer to that question has
implications for life on other planets, such as
Mars, scientists say.
"It opens up your horizons for what's
possible," Shirey said. "If you think that you
can have microbial life throughout the entire
crust of the Earth, then all of a sudden it
becomes very possible that life could live on
other planets under the right condition."
That raises questions about potential life in
relatively warm rock located beneath the
cold surface of Mars, where liquid water
could still exist.
"We're looking at billion-year-old rock here
and we can still find flowing water that's full
of the kind of energy that can support life,"
Sherwood Lollar said.
"If we find Martian rocks of the same age
and in places of similar geology and
mineralogy to our site, then there's every
reason to think that we might be able to find
the same thing in the deep subsurface of
Mars."
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