Author of the article: Scott McLean
Publishing date: Aug 09, 2021 •
Ancient lake flood spanned the prairies, factored in ice age: U of A research
Author of the article:Nicole Bergot
Publishing date:Aug 09, 2021 •
Publishing date: Aug 09, 2021 •
Sophie Norris, who led a team of researchers as a University of Alberta Faculty of Science PhD student, takes samples in Fort McMurray Wood Buffalo's rural areas. Norris was studying an ancient flood that covered much of the prairies 12,000 years ago. Supplied Image/University of Alberta
A flood that covered Fort McMurray roughly 12,000 years ago could offer researchers insights into what drives rapid climate change.
The epic flooding, which was led by researcher at the University of Alberta, is one of the largest of its kind in the planet’s history. Sophie Norris, who led the team as a U of A Faculty of Science PhD student, says the flood from melting glaciers could have altered the circulation of the world’s oceans. This would have caused temperatures to drop and ushered in an ice age.
“What’s really interesting and important about this lake is that as it drained, it occurred at the same time as we were going into a sort of warm period more like the climate conditions that we have today,” said Norris in an interview.
The flood waters drained from an ancient glacial lake called Agazzis, which formed nearly 16,000 years ago. At 1.5-million square kilometres, the lake was roughly the size of Mongolia and larger than any lake that exists today. It stretched across Saskatchewan and Manitoba and crossed into northeastern Alberta, including what is now the Fort McMurray Wood Buffalo area.
The glacier melted fast enough to fill 800 Olympic swimming pools every second and gave way to enough water to fill the Great Lakes.
The floodwaters flowed northwest through a channel referred to as the Clearwater-Athabasca Spillway, which passed through Fort McMurray, and into the MacKenzie River Basin. The rushing waters did not stop until it reached the Arctic Ocean.
The flood corresponds with a period called the Younger Dryas. The northern hemisphere was coming out of an ice age but suddenly returned to near-glacial conditions. Norris and other researchers are planning more studies to understand the flood’s relationship to the Younger Dryas.
“The [flood] that goes through the Fort McMurray area is one of the leading culprits for [rapid climate change],” said Duane Froese, Canada Research Chair in Northern Environmental Change and Norris’ PhD supervisor at the University of Alberta, in an interview. “But up until now we never had a really good estimate of exactly how much water went through and what the source of that water was.”
The flooding in the Clearwater Valley was enough to cover houses, while geographically the terrain at the time was at the level of the Fort McMurray International Airport. As the flood waters flowed north, gravel deposits were left in its wake.
“One of the things that’s really cool is just how much construction and development around the Fort McMurray area intercepts these flood deposits,” said Froese.
“From building basements and housing developments through mining and the oilsands developments themselves.”
A flood that covered Fort McMurray roughly 12,000 years ago could offer researchers insights into what drives rapid climate change.
The epic flooding, which was led by researcher at the University of Alberta, is one of the largest of its kind in the planet’s history. Sophie Norris, who led the team as a U of A Faculty of Science PhD student, says the flood from melting glaciers could have altered the circulation of the world’s oceans. This would have caused temperatures to drop and ushered in an ice age.
“What’s really interesting and important about this lake is that as it drained, it occurred at the same time as we were going into a sort of warm period more like the climate conditions that we have today,” said Norris in an interview.
The flood waters drained from an ancient glacial lake called Agazzis, which formed nearly 16,000 years ago. At 1.5-million square kilometres, the lake was roughly the size of Mongolia and larger than any lake that exists today. It stretched across Saskatchewan and Manitoba and crossed into northeastern Alberta, including what is now the Fort McMurray Wood Buffalo area.
The glacier melted fast enough to fill 800 Olympic swimming pools every second and gave way to enough water to fill the Great Lakes.
The floodwaters flowed northwest through a channel referred to as the Clearwater-Athabasca Spillway, which passed through Fort McMurray, and into the MacKenzie River Basin. The rushing waters did not stop until it reached the Arctic Ocean.
The flood corresponds with a period called the Younger Dryas. The northern hemisphere was coming out of an ice age but suddenly returned to near-glacial conditions. Norris and other researchers are planning more studies to understand the flood’s relationship to the Younger Dryas.
“The [flood] that goes through the Fort McMurray area is one of the leading culprits for [rapid climate change],” said Duane Froese, Canada Research Chair in Northern Environmental Change and Norris’ PhD supervisor at the University of Alberta, in an interview. “But up until now we never had a really good estimate of exactly how much water went through and what the source of that water was.”
The flooding in the Clearwater Valley was enough to cover houses, while geographically the terrain at the time was at the level of the Fort McMurray International Airport. As the flood waters flowed north, gravel deposits were left in its wake.
“One of the things that’s really cool is just how much construction and development around the Fort McMurray area intercepts these flood deposits,” said Froese.
“From building basements and housing developments through mining and the oilsands developments themselves.”
Author of the article:Nicole Bergot
Publishing date:Aug 09, 2021 •
An illustration of a family of Woolly Mammoths grazing on what is left of the grasses as winter approaches in this ice age scene. PHOTO BY AUNT_SPRAY /Getty Images/iStockphoto
Article content
An epic glacial lake flood spanning Canada’s prairies may have been swift enough to trigger the ice age roughly 12,000 years ago, shows research lead by the University of Alberta.
The flood from the ancient 1.5-million square kilometre Glacial Lake Agassiz drained at a rate of more than 800 Olympic swimming pools a second, a finding that supports the theory that it may have propelled the warming Earth back into an ice age, said a recent U of A news release.
Sophie Norris, a former U of A Faculty of Science PhD student, led the study to determine how much water was discharged through the meltwater channel from the lake spanning what is now southern Manitoba and central Saskatchewan, up to the Alberta border.
“We know that a large discharge has gone through the area but the rate of the discharge or the magnitude was pretty much unknown,” said Norris, who finished her PhD under the supervision of Duane Froese, in a statement.
When the three-kilometre-thick Laurentide Ice Shield atop North America started to melt about 16,000 years ago, the lake formed, creating a dam that stopped any meltwaters spreading to Hudson Bay, say researchers. But the lake eventually spilled out to the northwest, along the major channel known as the Clearwater-Athabasca Spillway, through what is now Fort McMurray, into the Mackenzie River basin en route to the Arctic Ocean.
Norris added that Alberta might owe part of its resource wealth to the great flood.
“The oilsands region is essentially within the channel that this flood formed,” she said. “There would have been a huge amount of quaternary material on top of that, as there is in the surrounding area, but it has been exposed in Fort McMurray by this huge event.”
The first part of her international study used sedimentary evidence to estimate the flood water’s force, as well as more than 100 valley cross-sections to estimate flow sizes. The research team created a model of gradual dam failure, then determined an estimated discharge rate, at its height, of two million metres cubed of water every second. That means the flood drained about 21,000 cubic kilometres of water — or the amount of water contained in the Great Lakes — in less than nine months.
“What I find deeply satisfying is that modern hydraulic modelling, when applied to the evidence preserved in the landscape, shows how a phenomenal flood propagated 12,000 years ago,” said Paul Carling, study co-author from the University of Southampton, U.K.
The event was likely the largest terrestrial flood ever recorded from the overtopping of a lake, said co-author Daniel Garcia-Castellanos, from Geosciences Barcelona in Spain. “It also suggests that we are getting close to quantitatively understanding these rapid erosional-flooding events and linking them with the long-term erosion of landscapes.”
The time of the flood also corresponds to an event known as the Younger Dryas, when just as the northern hemisphere was coming out of the ice age, it suddenly returned to near-glacial conditions.
“During the Late Pleistocene, temperatures were returning to normal, when the Earth slipped back into an ice age,” added Duane Froese, Norris’s PhD supervisor and Canada Research Chair in Northern Environmental Change in the Department of Earth and Atmospheric Sciences.
“We don’t know for sure that the flood caused the Earth to slip back into the ice age, but certainly if you put that much water into the Arctic Ocean, the models show you get cooling of the northern hemisphere climate.”
Norris said the next step for researchers is to better understand whether the flood occurred at the start of the cold reversal, where it may have been the cause, or just played a part in more complex events that followed.
The paper, ‘Catastrophic Drainage From the Northwestern Outlet of Glacial Lake Agassiz During the Younger Dryas,’ has been published in Geophysical Research Letters.
Article content
An epic glacial lake flood spanning Canada’s prairies may have been swift enough to trigger the ice age roughly 12,000 years ago, shows research lead by the University of Alberta.
The flood from the ancient 1.5-million square kilometre Glacial Lake Agassiz drained at a rate of more than 800 Olympic swimming pools a second, a finding that supports the theory that it may have propelled the warming Earth back into an ice age, said a recent U of A news release.
Sophie Norris, a former U of A Faculty of Science PhD student, led the study to determine how much water was discharged through the meltwater channel from the lake spanning what is now southern Manitoba and central Saskatchewan, up to the Alberta border.
“We know that a large discharge has gone through the area but the rate of the discharge or the magnitude was pretty much unknown,” said Norris, who finished her PhD under the supervision of Duane Froese, in a statement.
When the three-kilometre-thick Laurentide Ice Shield atop North America started to melt about 16,000 years ago, the lake formed, creating a dam that stopped any meltwaters spreading to Hudson Bay, say researchers. But the lake eventually spilled out to the northwest, along the major channel known as the Clearwater-Athabasca Spillway, through what is now Fort McMurray, into the Mackenzie River basin en route to the Arctic Ocean.
Norris added that Alberta might owe part of its resource wealth to the great flood.
“The oilsands region is essentially within the channel that this flood formed,” she said. “There would have been a huge amount of quaternary material on top of that, as there is in the surrounding area, but it has been exposed in Fort McMurray by this huge event.”
The first part of her international study used sedimentary evidence to estimate the flood water’s force, as well as more than 100 valley cross-sections to estimate flow sizes. The research team created a model of gradual dam failure, then determined an estimated discharge rate, at its height, of two million metres cubed of water every second. That means the flood drained about 21,000 cubic kilometres of water — or the amount of water contained in the Great Lakes — in less than nine months.
“What I find deeply satisfying is that modern hydraulic modelling, when applied to the evidence preserved in the landscape, shows how a phenomenal flood propagated 12,000 years ago,” said Paul Carling, study co-author from the University of Southampton, U.K.
The event was likely the largest terrestrial flood ever recorded from the overtopping of a lake, said co-author Daniel Garcia-Castellanos, from Geosciences Barcelona in Spain. “It also suggests that we are getting close to quantitatively understanding these rapid erosional-flooding events and linking them with the long-term erosion of landscapes.”
The time of the flood also corresponds to an event known as the Younger Dryas, when just as the northern hemisphere was coming out of the ice age, it suddenly returned to near-glacial conditions.
“During the Late Pleistocene, temperatures were returning to normal, when the Earth slipped back into an ice age,” added Duane Froese, Norris’s PhD supervisor and Canada Research Chair in Northern Environmental Change in the Department of Earth and Atmospheric Sciences.
“We don’t know for sure that the flood caused the Earth to slip back into the ice age, but certainly if you put that much water into the Arctic Ocean, the models show you get cooling of the northern hemisphere climate.”
Norris said the next step for researchers is to better understand whether the flood occurred at the start of the cold reversal, where it may have been the cause, or just played a part in more complex events that followed.
The paper, ‘Catastrophic Drainage From the Northwestern Outlet of Glacial Lake Agassiz During the Younger Dryas,’ has been published in Geophysical Research Letters.
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