Evidence of 12,000-year-old flood that drained ancient lake at high rate of speed found

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Researchers have found evidence that a flood which happened more than 12,000 years ago and drained an ancient lake at the speed of more than 800 Olympic swimming pools per second may have pushed the Earth back into an ice age.

A team of experts – led by the researchers at the University of Alberta – found evidence that Glacial Lake Agassiz started to spill out to the northwest in a channel known as the Clearwater-Athabasca Spillway. 

This spillage may have caused the Younger Dryas cooling event, some 13,000 years ago.

The ancient lake, which no longer exists, covered an area of 580,000 square miles in modern-day southern Manitoba, central Saskatchewan all the way up to the Alberta border.

Researchers, including Sophie Norris (pictured), have found evidence that a 12,000 year-old flood that drained a lake at speeds of more than 800 Olympic swimming pools per second may have pushed Earth back into an ice age

Researchers, including Sophie Norris (pictured), have found evidence that a 12,000 year-old flood that drained a lake at speeds of more than 800 Olympic swimming pools per second may have pushed Earth back into an ice age 

The ancient lake, which no longer exists which covered an area of 580,000 square miles in modern-day southern Manitoba, central Saskatchewan all the way up to the Alberta border

The ancient lake, which no longer exists which covered an area of 580,000 square miles in modern-day southern Manitoba, central Saskatchewan all the way up to the Alberta border

The researchers - using sedimentary evidence, more than 100 valley cross sections and a model of the bedrock's erodibility and size of the lake- estimated that at the height of the spillage, 2 million cubic meters of water were discharged every second

The researchers – using sedimentary evidence, more than 100 valley cross sections and a model of the bedrock’s erodibility and size of the lake- estimated that at the height of the spillage, 2 million cubic meters of water were discharged every second

‘One suggestion is the drainage of meltwater from glacial Lake Agassiz, a large ice-dammed lake in central North America, into the surrounding oceans may have affected ocean circulation, contributing to this climatic event,’ researchers wrote in the study.

It’s likely that the ‘catastrophic meltwater to drain to the Arctic Ocean’ occurred over a 6–9 month period during the Younger Dryas, but they are not yet clear if this happened during the beginning of the event.  

‘We know that a large discharge has gone through the area but the rate of the discharge or the magnitude was pretty much unknown,’ the study’s lead author, Sophie Norris, said in a statement

Over the span of roughly nine months, approximately 5,000 cubic miles (21,000 cubic kilometers) were drained from the lake, roughly the equivalent of all the Great Lakes combined

Over the span of roughly nine months, approximately 5,000 cubic miles (21,000 cubic kilometers) were drained from the lake, roughly the equivalent of all the Great Lakes combined 

Using sedimentary evidence, more than 100 valley cross sections, and a model comprised of gradual dam failure with the bedrock’s erodibility and the size of the lake, the researchers estimated that 2 million cubic meters of water were discharged every second at the height of the spillage, making it one of the largest floods known to occur on Earth.

For comparison purposes, this is roughly 10 times what the Amazon River spills every second. 

Over the span of roughly nine months, approximately 5,000 cubic miles (21,000 cubic kilometers) were drained from the lake, roughly the equivalent of all the Great Lakes combined.  

The ancient lake was formed after the Laurentide Ice Shield started to melt around 16,000 years ago, creating a dam that prevented meltwaters from entering the Hudson Bay

The ancient lake was formed after the Laurentide Ice Shield started to melt around 16,000 years ago, creating a dam that prevented meltwaters from entering the Hudson Bay

The ancient lake was formed after the Laurentide Ice Shield started to melt around 16,000 years ago, creating a dam that prevented meltwaters from entering the Hudson Bay.

‘What I find deeply satisfying is that modern hydraulic modeling, when applied to the evidence preserved in the landscape, shows how a phenomenal flood propagated 12,000 years ago,’ said University of Southampton researcher and study co-author Paul Carling.  

‘When all the uncertainties are considered, the outcome remains pretty solid.’ 

Although scientists are not sure what caused the Earth to slip back into an ice age, the lake flooding theory is certainly plausible, study co-author Froese added.

WHAT IS THE YOUNGER DRYAS IMPACT HYPOTHESIS?

The Younger Dryas impact hypothesis proposes that fragments of a disintegrating comet struck the Earth around 12,800 years ago.

These fragments bombarded North and South America, Europe and western Asia.

This generated a thin layer of detritus covering around 19.3 million square miles (50 million square kilometers).

This layer contained concentrations of platinum, meltglass and nano-diamonds from the impactors. 

Experts argue that this episode saw large-scale biomass burning, an impact-induced winter, longer-time climatic shifts and the extinction of late Pleistocene megafauna.

‘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.’ 

The researchers will next try to find out whether the flood happened at the start of the Younger Dryas climate event, which may have been the root cause of it, or if it was just a part of other events.

It’s also possible the floods resulted in the region’s expansive oil sands, a region of loose sand, water and clay that also has a form of petroleum.

‘The oil sands region is essentially within the channel that this flood formed,’ Norris explained. ‘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 study was published last month in Geophysical Research Letters.

There are several theories about what caused the Younger Dryas cooling event that lasted about 1,500 years.

In June, a separate group of researchers said that a cosmic impact, likely an asteroid, hit Earth and likely triggered the Younger Dryas climate shift. 

This shift was potentially the most ‘devastating impact since the extinction of the dinosaurs’ and resulted in a mini Ice Age that lasted more than 1,000 years. 

Several other studies over the years have supported the theory of an ancient asteroid strike. 

Others, however believe the Younger Dryas cooling event was caused by other methods. In 2020, another study suggested it was caused by ancient volcanic eruptions and not meteor impacts. 

Some have even suggested that an hour-long hailstorm from space plunged the planet into the mini-ice age. 

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