Lake Agassiz
The Lake Agassiz was at the end of the last ice age ( Wisconsin glaciation in North America called ), whose area was greater than that of today's Great Lakes put together a prehistoric lake in central North America. He was first mentioned in 1823 by William H. Keating 1879 and named after Louis Agassiz, who recognized the emergence of the lake of glacier water.
Location
The existing today remnants of the former lake - of which the largest is Lake Winnipeg (followed by the Winnipegosis and from Manitobasee and the Lake of the Woods ) - dominate the geography of Manitoba. During its formation approximately 11,700 years ago, he covered much of Manitoba, Saskatchewan, Ontario, the West, and the North Minnesota and North Dakota. At its greatest extent it stretched over an area of about 440,000 km ² and was larger than any present-day inland waterways, including the Caspian Sea.
Outlet of the lake and the influence on the Earth's climate
How many large glacier lakes on the edge of Lake Agassiz was largely an Ice Lake, which flowed several times within a short period of glacial cycles, which could reach catastrophic proportions. Assessments of individual flood events occurred water runoff from 0.07 to 0.64 Sverdrup (106 m³ / s) for individual events.
The lake had several drains into the River Warren, the Minnesota River ( part of the Mississippi River), in the Great Lakes or to the west by the Yukon Territory and Alaska. During a re- glacial expansion 9900 years ago, the lake decreased its size and withdrew behind the present border of Canada. These events had a significant influence on climate, sea level and possibly human to the former settlement of North America. Climatologists believe that a major outbreak of the lake in the Great Lakes, the adjoining St. Lawrence River and the Atlantic Ocean about 13,000 years ago by the large amounts of fresh water interrupted the Gulf Stream, and ensured a about a millennium -lasting cooling of the earth, the is called the Younger Tundra.
The last major change in the outflow took place about 8,400 years ago when the Agassiz flowed into Hudson Bay. During the next 1000 years, the lake dried up almost completely, leaving it under other Lake Winnipeg, Lake Winnipegosis to the Manitobasee and the Lake of the Woods. These lakes are shrinking because of postglacial land uplift still slow. The drying up of the lake happened very quickly, sometimes it only took a year, as has been seen in ice cores.
Although the lake is almost completely gone along with the ice that has fed him, he still has left on a large land tracks: miles and miles away from any water beaches are obvious traces that can be found in many places along the former shore. Valleys of former inflows and outflows are present river valleys, including that of the Red River, the Assiniboine River and the Minnesota River.