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The Great Lakes

The Great Lakes. Brandon Dunn, Kate Thometz, Vince Amicon. H uron O ntario M ichigan E rie S uperior. Largest group of fresh water lakes worldwide Borders United States and Canada Used today as major source of transportation. THE GREAT LAKES. GEOLOGIC HISTORY.

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The Great Lakes

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  1. The Great Lakes Brandon Dunn, Kate Thometz, Vince Amicon

  2. Huron Ontario Michigan Erie Superior

  3. Largest group of fresh water lakes worldwide Borders United States and Canada Used today as major source of transportation THE GREAT LAKES

  4. GEOLOGIC HISTORY • Formed as a result of the Ice Age 10,000 years ago • The Lauren tide Glaciation melted with rising temperatures and dug a whole in the Earth’s crust • The water from the glacier filled the holes and became the Great Lakes • Due to erosion, many small mountains formed the present-day Great Lake Islands

  5. Lake Superior Largest of the great lakes in area and volume. Contains 10 percent of the worlds fresh water supply. Lake Superior was formed 1.1 to 1.2 billion years ago during the Mid-continent Rift. For over 2 million years, thick flows of lava (flood basalts) repeatedly broke up the surface. During extended periods between these flows, the crust sank downward, creating a basin that accumulated sediments until the cycle began again with the next flood of molten lava.

  6. Lake Michigan • The third largest of the lakes and sixth largest freshwater in the world. • 3,200 miles of shoreline, the longest of any state but Alaska

  7. Lake Huron • Lake Huron is the second largest Great Lake by surface area and the fifth largest freshwater lake in the world. • Huron was the first of the Great Lakes to be discovered by European explorers. • Lake Huron is surrounded by forest life and still has many rich natural resources.

  8. Background • The Great Lakes is a group of five freshwater lakes in central North America. It creates a natural border between the United States and Canada. • It is the largest body of freshwater in the world, with a combined surface area of 95,000 sq mi. • From west to east the lakes are Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario. • The distance from the western end of Lake Superior, to the outlet of Lake Ontario is 1,160 mi. VA

  9. How the lakes were formed • The Great Lakes were formed approximately at the end of the Pleistocene period, when the glacier-carved lake basins were filled with melt water from the retreating ice sheet. • The lakes are connected to each other by straits, short rivers, and canals. • The height above sea level of the lake surfaces varies from Lake Superior's 602 ft, to Lake Ontario's 246 ft; • The greatest sudden drop occurs at Niagara Falls 167 ft between lakes Erie and Ontario. VA

  10. Rock Formations • As the glaciers receded their leading edges left behind high ridges and incredible rock formations. • There were 8-12 ice ages that formed these incredible rock formations like the one pictured are the right. • The last glacier began to melt around 14,000 years ago. The melting water filled the huge holes left by the glaciers. • The lakes were originally much larger than they are now. But as more ice melted the St. Lawrence river revealed itself as an outlet to the Atlantic Ocean and so the lake levels dropped to their current levels. VA

  11. Great Lakes Geology • Both molten lava and glaciers shaped the shorelines and inland lands of the great lakes. • The giant columns of the palisades are an example of solidified lava. • The northwestern section of lake superior is known as Isle Royale National Park and is a prime example of the differences between the molten lava landscape and the glacier landscape. VA

  12. Great Lakes Geology • The Isle Royale’s southern shoreline is made up of reddish sedimentary rocks deposited during a long pause in the retreating of the last glacier from Isle Royale, approximately 11,000 years ago. • The shores are flat similar to those of sandy beaches in many tropical areas.

  13. Great Lakes Geology • The northern shoreline of the Isle Royale is composed of rocky bluffs that are a prime example of the cutting of the glaciers through the earths crust.

  14. Destructive Erosion • A current problem with many great lakes shorelines is erosion. • In the picture to the left is a picture of a house that has fallen into the water as a result of the earth below the house being eroded away by the continual beating of the waves on the loose shoreline.

  15. Beach Erosion • Beach erosion is also a problem that many great lakes shorelines have. • Beaches are very important to the ecology of the lakes. • The great lakes environment depends greatly on the beach shoreline and would be dramatically different without them.

  16. Transportation Erosion • Another type of erosion that has caused many problems is that to roadways along the shorelines of many of the great lakes. • To the left is a picture of a roadway that has collapsed due to erosion from underneath the pavement.

  17. References • http://www.great-lakes.net/teach/ • http://www.lre.usace.army.mil/ • http://www.great-lakes.net/ • http://www.glsc.org/ • http://www.epa.gov/glnpo/atlas/ • http://www.michigan.gov/deq/0,1607,7-135-3311_4112_4233-9336--,00.html • http://www.uwgb.edu/dutchs/glkhist/glkhist0.htm • http://geology.about.com/od/lakes/

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