Saturday, July 17, 2010

Something Fishy Here


Bones of giant predatory fish unearthed in Manitoba

Lake Agassiz left a lot of interesting stuff behind, especially in Manitoba.

Scroll down for some info on Lake Agassiz's impact on a sudden and drastic cooling in Northern Europe.
"Lake Agassiz outburst sparked 'Big Freeze' in Europe 12,800 years ago. When an ice wall collapsed somewhere along Lake Agassiz's northeastern rim about 12,800 years ago, its freshwater contents gushed rapidly into the North Atlantic, wreaking havoc with ocean circulation patterns and plunging Europe into an unprecedented and prolonged winter that lasted centuries. In a study that highlights just how quickly a mini ice age took hold of Europe after the dramatic collapse of a glacial ice dam in ancient Canada, Saskatoon scientist Bill Patterson has gathered evidence suggesting the "Big Freeze" - a sudden and severe global cooling known to experts as the Younger Dryas - happened within three months of the Canadian cataclysm. But rather than unfolding over a decade as widely believed, the extreme chill set in so swiftly that ecosystems in the northern hemisphere were radically transformed within a single season [Try adapting to that!], a research project led by Patterson has discovered. "If (Canada's earliest aboriginals) lived near Agassiz, they may simply have seen the lake level drop as the lake shrunk in size," Patterson said. "If they were in the East near the outlet, they would have seen what would look like a large, fast flowing river."

"Between approximately 11,100 and 10,900 years ago, Lake Agassiz’s north and northeastern shores consisted of a continuous cliff of ice, but its eastern and western shores formed what geologists refer to as the “Campbell Beach.” This extensive sand and gravel ridge, most evident in south-western Manitoba, is possibly the most eloquent testimony to the existence of this once-great lake. Shortly thereafter, a new outlet through the ice opened into the Lake Superior basin, thus allowing Agassiz to drain in that direction. A glacial readvance subsequently blocked this outlet and the lake rose to the Campbell Beach once again. This stage too was relatively short-lived; some 9500 years ago the eastern outlet re-opened and Agassiz drained rapidly—probably with catastrophic results. As much as 3000 cubic kilometers of water (seven times the volume of Lake Erie) coursed into the Superior Basin in just a few weeks."

Global warming zealots should take note. The Earth's system is continually changing, sometimes slowly, sometimes rapidly, with catastrophic consequences, with or without human intervention.

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