Posted on 02/25/2008 2:36:06 AM PST by 2ndDivisionVet
Canadian geologists say they can shed light on how a vast lake, trapped under the ice sheet that once smothered much of North America, drained into the sea, an event that cooled Earth's climate for hundreds of years.
During the last ice age, the Laurentide Ice Sheet once covered most of Canada and parts of the northern United States with a frozen crust that in some places was three kilometres (two miles) thick.
As the temperature gradually rose some 10,000 years ago, the ice receded, gouging out the hollows that would be called the Great Lakes.
Beneath the ice's thinning surface, an extraordinary mass of water built up -- the glacial lake Agassiz-Ojibway, a body so vast that it covered parts of Manitoba, Saskatchewan, North Dakota, Ontario and Minnesota.
And then, around 8,200 years ago, Agassiz-Ojibway massively drained, sending a flow of water into the Hudson Strait and into the Labrador Sea that was 15 times greater than the present discharge of the Amazon River.
By some estimates, sea levels rose 14 metres (45 feet) as a result.
How the great flood was unleashed has been a matter of debate.
Some experts suggest an ice dam was smashed down, or the gushing water spewed out over the top of the icy lid.
Quebec researchers Patrick Lajeunesse and Guillaume Saint-Onge believe, though, that the outburst happened under the ice sheet, rather than above it or through it.
In a study appearing on Sunday in the journal Nature Geoscience, the pair describe how they criss-crossed Hudson Bay on a research vessel, using sonar to scan more than 10,500 kilometres (6,000 miles) to get a picture of the bay floor.
In the south of the bay, they found lines of deep waves in the sandy bed, stretching more than 900 kilometres (562 miles) in length and some 1.7 metres (5.5 feet) deep.
These are signs that the bay's floor, protected by the mighty lid of ice, was swept by a mighty current many years ago but has been still ever since, they say.
In the west of the bay, they found curious marks in the shape of parabolas twisting around to the northeast.
The arcs were chiselled as much as three metres (10 feet) into the sea bed and found at depths of between 80 and 205 metres (260 and 666 feet).
The duo believe that this part of the bay had icebergs that were swept by the massive current.
The bergs' jagged tips were trapped in the sea bed and acted like a pivot. As the icebergs swung around, other protruding tips ripped arc-like tracks on the bay floor.
Also presented as evidence are deep submarine channels and deposits of red sediment that stretch from land west of Hudson Bay right across the northwestern floor of the bay itself -- both point to a current that swept all before it.
"Laurentide ice was lifted buoyantly, enabling the flood to traverse southern Hudson Bay under the ice sheet," the study suggests.
Previous work suggests the flood was so huge that it affected climate around the world.
The influx of freshwater into the North Atlantic reduced ocean salinity so much that this braked the transport of heat flowing from the tropics to temperate regions.
Temperatures dropped by more than three degrees Celsius (5.4 degrees Fahrenheit) in Western Europe for 200-400 years -- a mini-Ice Age in itself.
WHOA I wonder if Looter guy ancenstor was there LOL!
But, you see, THIS event is (mis)used now to explain “how” the coming global warming will destroy the Gulf Stream and cause another global catastrophe ... Thus requiring socialistic controls over everybody's’s power and energy.
But, what the AGW extremists (conveniently) ignore is that - today - there is NO ice mass this big across Canada - therefore, there can be NO mass melting and NO interruption of the Gulf Stream.
History CANNOT repeat itself (this time!) because the precursors are completely absent! Yet, this time, because it IS convenient for the AGW extremists to -re-use history, they DO WANT to repeat this scenario.
(Note also that there is written history of a massive flood about this frame in the MidEast and around the world
Every civilization has a “great flood” myth because ...
... every once in a while, there is a once-in-500-year great flood.
Odds are, every place on the planet other than mountain-tops has been great flooded at least once.
I grew up a thousand miles away from you, and about four miles from the lake’s shoreline. Big lake.
Regarding the article: I’m impressed with these scientists. Insight and intuition, followed up by real research that tends right now to support their hypothesis.
This is how science needs to be done. I commend them.
Fossil fish capital of the world? Kemmerer, Wyoming, just south of Jackson.
Great insight. I agree with your assessment completely.
At one time the entire western United States was under water.
That is a LOT of water.
Very interesting area of the coutry. Dinosaur National Monument is just south of Kemmerer in Colorado, and morte dinosuar stuff at Vernal, Utah. The website says that the area around Kemmerer was a “sub-tropical” lake. Other evidence from around the area suggests that the entire Western United States was under water at one time.
http://www.nps.gov/fobu/index.htm
“Odds are, every place on the planet other than mountain-tops has been great flooded at least once.”
The peak of Mt. Everest is littered with marine fossils.
Now that's climate change.
read
 |
||
| · join · view topics · view or post blog · bookmark · post new topic · | ||
The Cycle of Cosmic Catastrophes:
Flood, Fire, and Famine
in the History of Civilization
by Richard Firestone,
Allen West, and
Simon Warwick-Smith
Wouldn't the gouging have occurred while the ice was building up and moving forward, not while it was melting (receding)?
I found that odd too. Doesn't seem to be mathematically possible.
I’m so glad we have global warming here in the midwest. It’s more than 20 degrees below normal as it is. I can’t imagine how cold it would be without global warming.
One of the zombies in my family made some cryptic stupid remark about how “people don’t understand” how the weather could be colder because of global warming. The cult think is pretty disturbing.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
