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The Glacial History and Geographic Regions of Michigan Geography of Michigan Michigan: based on the Chippewa Indian word "meicigama" meaning great water. Mount Arvon is Michigan's highest point. Rising 1,979 feet above sea level Michigan consists of two peninsulas that are separated by the Straits of Mackinac, and some nearby islands At a total of 97,990 square miles (253,793 km²), Michigan is the largest state east of the Mississippi River Lake Superior is the deepest of the five Great Lakes. Lake Erie is the shallowest of the five Great Lakes Three short rivers are vital to the economy of the state as they carry goods among the Great Lakes: Detroit River, St. Clair River and St. Mary's River, where the Soo Locks are located Kettle Lakes Kettle Lakes: Kettles are depressions left behind after partially-buried ice blocks melt. Many are filled with water, and are then called "kettle lakes". Most lakes in Michigan could be described as kettle lakes, and the term "kettle lake" describes the way the lake basin was formed. Kettle lake basins were formed as the glaciers receded Examples: Higgins Lake and Walled Lake, The Glacial History of Michigan The landforms of Michigan are a result of major changes brought about by continental glaciations. Landforms can be depositional or erosional in nature. The Glacial History of Michigan Glacial landforms dominate the surface of the whole state except the western half of the U.P., where eroded remnants of some of the oldest mountains on earth are found. There is considerable diversity in MI—from glacial lake plains near Detroit, to sand dunes bordering Lake Michigan, to massive moraines in the northern lower peninsula. The Glacial History of Michigan The last ice age occurred during the Pleistocene Epoch (a division of time). It began 2 million years ago and ended approximately 12,000 years ago. We live in the Recent Epoch today (12,000 years ago to the present). The Glacial History of Michigan The last ice age was the fourth major ice age in Earth’s 4.6 billion year history. In addition to the northern U.S. and Canada, the last ice age created the glacial landforms of northern Europe and Siberia. Others occurred: 2.0 billion years ago 600 million years ago 250 million years ago (on Pangaea!) The Glacial History of Michigan During an ice age, it is not cold all the time. Long periods of cold temperatures and glaciations are broken up by equally long periods of warm temperatures during which glaciers recede and sea level rises. The warm periods are called interglacial's, meaning “in between times of glaciers.” The Glacial History of Michigan During a glacial period, snow fall accumulated into layers of ice in 4 regions of North America. The Glacial History of Michigan These huge masses of ice were up to 10,000 feet or more in thickness. They moved south into the U.S. leveling existing hills, filled in valleys, blocked drainage patterns of rivers, and gouged out major basins. The Glacial History of Michigan The Great Lakes were carved out from river valleys over the entire Pleistocene Epoch. With each advance of the ice, they got wider & deeper. The Glacial History of Michigan The depth of the lake is determined by the thickness of the ice at the time of glaciations. The farther north the lobe of ice, the thicker it was. Consequently, the lakes get more shallow in the southern Great Lakes region. LAKE: GREATEST DEPTH: Superior = 1,333 ft. Michigan = 925 ft. Huron = 725 ft. Ontario = 283 ft. Erie = 212 ft. The Glacial History of Michigan The Great Lakes are 5 of the lakes in a 5,000-mile long string of lakes through central and western Canada. Each was carved by huge continental ice sheets over the last 2 million years. The Glacial History of Michigan The moving ice carried sediments (small pieces of rock) long distances. Rocks from Canada have been found in Ohio and Indiana. Canadian Shield: The Canadian Shield, is a large area of exposed hard igneous rock covered by a thin layer of soil. stretches North from the Great Lakes to the Arctic Ocean, covering over half of Canada; it also extends South into the Northern reaches of the United States. As the ice melted, the sediments were deposited, creating huge landforms. Some sediments were deposited in large ridges and hills while others were carried away by vast amounts of melt-water streaming from the melting ice sheets. The Glacial History of Michigan Another major result of glaciations was the creation of a large number of inland lakes and wetlands. More than 11,000 inland lakes are largely the result of water accumulating in depressions left by passing glaciers. Much of the swamp land of Michigan was drained for agriculture. This accounted for the loss of 50% of Michigan’s wetlands. The Glacial History of Michigan The flattest areas of southeast Michigan are plains that are the result of deposits on the bottom of ancient lakes. Detroit and the northwest suburbs used to be under an ancient lake! Regions of Michigan What Determines A Region Geographic Vegetation Population Agriculture Placement Northern Michigan Small to medium size cities Large portion of Great Lakes shoreline Tourism is the main industry Frequently known to seasonal residents as “up north” Landmarks: Tahquamenon Falls State Park Tahquamenon Falls West Michigan Examples of different types of areas in the West Muskegon Grand Rapids Kalamazoo Boundaries are questionable & uncertain Economy: mostly agriculture (fruit, beets, corn, soy beans) Some automobile manufacturing Mid-Michigan Mainly farmland Moderate size cities Home to our State Capitol (Lansing) Flint/Tri-cities Region 2 sub regions: The Thumb & Greater TriCities Home to Flint 5th largest city in MI Many lakes & rivers Economy is dependent on manufacturing Michigan DOW Sugar Company Chemical Company Delphi Corporation Southeast Michigan Majority of state businesses & industries Over half of the states population Home of Detroit State’s largest city Lake Effect Wind blows across Lake Michigan from the west. In winter, the lake’s water is usually warmer than the air and warmer than the land. As the west winds move over the lake, they pick up warm lake moisture. By the time the winds reach the shore, they help to warm the land. This makes winter temperatures less harsh. In summer the opposite happens. The lake’s water is usually cooler than the air and the land. The west winds cool off as they blow over the lake and bring cool breezes to the land Summer Winter cooler warmer warmer cooler water land water land