|
A glacial lake of the Pleistocene Epoch extending over present-day northwest Minnesota, northeast North Dakota, southern Manitoba, and southwest Ontario.
| Dictionary: Agassiz, Lake |
|
| 5min Related Video: Lake Agassiz |
| Columbia Encyclopedia: Lake Agassiz |
| Wikipedia: Lake Agassiz |
Lake Agassiz was an immense glacial lake located in the center of North America. Fed by glacial runoff at the end of the last glacial period, its area was larger than all of the modern Great Lakes combined, and it held more water than contained by all lakes in the world today.[1]
Contents |
First postulated in 1823 by William Keating, it was named after Louis Agassiz in 1879 after he was the first to realize it was formed by glacial action.
Geologists have come to a consensus on the likely geological history of Lake Agassiz.
During the last Ice Age, northern North America was covered by a glacier, which alternately advanced and deteriorated with variations in the climate. This continental ice sheet formed during the period now known as the Wisconsin glaciation, and covered much of central North America between 30,000 and 10,000 years ago. As the ice sheet disintegrated, it created at its front an immense glacial lake, formed from its meltwaters.[2]
Around 13,000 calendar years before present (almost 12,000 14C years before present), the lake came to cover much of Manitoba, western Ontario, northern Minnesota, eastern North Dakota, and Saskatchewan. At its greatest extent, it may have covered as much as 440,000 square kilometers, larger than any currently existing lake in the world (including the Caspian Sea).
The lake drained at various times south through the Traverse Gap into Glacial River Warren (parent to the Minnesota River, a tributary of the Mississippi River),[3] east through Lake Kelvin (modern Lake Nipigon) to what is now Lake Superior,[4] or west via the Mackenzie River through the Yukon Territory and Alaska.[1] Climatologists believe that a major outbreak of Lake Agassiz about 13,000 BP drained through the Great Lakes and Saint Lawrence River into the Atlantic Ocean. This may be the cause of the Younger Dryas stadial.[1][5] A return of the ice for some time offered a reprieve, and after retreating north of the Canadian border about 9,900 years ago it refilled. These events had significant impact on climate, sea level and possible early human civilization.
Much of the final drainage of Lake Agassiz may have occurred in a very short time—perhaps as little as one year. A recent study by Turney and Brown links this rapid drainage and subsequent global sea level rise of about one meter to the expansion of agriculture in Europe; he suggests that this may also account for various flood myths of prehistoric cultures, including the Biblical flood.[6]
The last major shift in drainage occurred about 8,400 calendar years before present (about 7,700 14C years before present), when the lake took up its current watershed, draining into Hudson Bay. The lake drained nearly completely over the next 1,000 years or so.
Lake Winnipeg, Lake Winnipegosis, Lake Manitoba, and Lake of the Woods, among others, are relics of the ancient lake. The outlines and volumes of these modern lakes are still slowly changing due to differential isostatic rebound.
Other geological and geomorphological evidence for Lake Agassiz can also be seen today. Raised beaches, many kilometers from any water, mark the former boundaries of the lake at various times. Several modern river valleys, including those of the Assiniboine River and the Minnesota River, were originally cut by water entering or leaving the lake. The fertile soils of the Red River Valley, now drained by the Red River of the North, are formed from lacustrine deposits of silt from Lake Agassiz.
Coordinates: 51°N 98°W / 51°N 98°W
This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)
| Manitoba, Lake | |
| Winnipeg, Lake | |
| Big Stone Lake (lake, Minnesota/South dakota) |
| What is the first second third forth fith sixth seventh eighth and nineth towns and citys of lake agassiz? Read answer... | |
| Lake Huron Lake Michigan Lake Erie Lake Ontario Lake Superior which is largest? Read answer... | |
| Which lakes do you prefer going to Norris lake fort loudon lake watts barr lake or tellico lakes and your opions on the lakes that you do not like and why? Read answer... |
| Agassiz found rock formations from Canada around Lake Superior in what year? | |
| Was louis agassiz wealthy? | |
| What did louis agassiz invent? |
Copyrights:
![]() | Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2007. Published by Houghton Mifflin Company. All rights reserved. Read more | |
![]() | Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/. Read more | |
![]() | Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Lake Agassiz". Read more |
Mentioned in