The Mysteries Of North America's Great Lakes | Naked Science | Spark

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The Great Lakes store one-fifth of the world's drinking water, impacting North America's climate significantly, with Lake Superior, Lake Michigan, and Lake Huron providing drinking water for over 10 million people. The Lakes formed around 9,000 years ago, with evidence pointing to ice as the force that carved their basins, while the retreat of Niagara Falls and a comet impact 12,900 years ago also reshaped the region.

Insights

  • The Great Lakes store a vast amount of fresh water, impacting North America's climate significantly and providing drinking water for millions of people in cities like Chicago and Detroit.
  • The formation of the Great Lakes, believed to be carved out by the Laurentide ice sheet over millennia, is a result of glacial ice erosion, similar to processes seen in other parts of the world like Iceland, with the Lakes dating back around 9,000 years and continuing to evolve due to various geological forces.

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Recent questions

  • How much water do the Great Lakes hold?

    The Great Lakes store 5,500 cubic miles of fresh water, enough to flood the continental US 9 feet deep and cover an area larger than Utah.

  • What is the deepest lake among the Great Lakes?

    Lake Superior is the deepest of the Great Lakes, with a depth of over 1,300 feet.

  • How many people rely on Lake Michigan and Huron for drinking water?

    Over 10 million people in cities like Chicago and Detroit rely on Lake Michigan and Huron for their drinking water supply.

  • What generates electricity for around 5 million homes near the Great Lakes?

    Niagara Falls, located between Lake Erie and Ontario, sees over 40 million gallons of water flow over it every minute, generating electricity for around 5 million homes.

  • How old are the Great Lakes estimated to be?

    Geologists estimate that the Great Lakes formed around 9,000 years ago, with early Lakes resembling the barren, sediment-filled proglacial Lakes seen in Iceland.

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Summary

00:00

The Great Lakes: North America's Water Giants

  • The Great Lakes store one-fifth of the world's drinking water, acting like Inland Seas that impact North America's climate significantly.
  • These Lakes hold enough water to flood the continental US 9 feet deep and cover an area larger than Utah, containing 5,500 cubic miles of fresh water.
  • Lake Superior, the deepest of the Lakes, is over 1,300 feet deep, while Lake Michigan and Huron provide drinking water for over 10 million people in Chicago and Detroit.
  • Niagara Falls, between Lake Erie and Ontario, sees over 40 million gallons of water flow over it every minute, generating electricity for around 5 million homes.
  • The formation of the Great Lakes is a mystery, with clues found on Kelly's Island in Lake Erie, where deep grooves in Ancient Rock hint at their origins.
  • Various theories, including volcanism and running water, are explored, but evidence points to ice as the force that carved the Lakes' basins.
  • Glacial ice, like the Vatnajökull Glacier in Iceland, grinds through Solid Rock, leaving behind deep depressions and carving out basins, similar to the Great Lakes.
  • The Laurentide ice sheet, a massive glacier that covered much of North America for over a million years, is believed to have gouged out the Great Lakes' basins.
  • Geologists estimate that the Laurentide ice sheet eroded around 1 ton of solid rock every 100 years, shaping the vast Lake basins over millennia.
  • Radiocarbon dating of sediment cores from Willow Be Bog between Lakes Erie and Ontario suggests that the Lakes formed around 9,000 years ago, with early Lakes resembling the barren, sediment-filled proglacial Lakes seen in Iceland.

22:54

Niagara Falls: Geological Timepiece of Great Lakes

  • Niagara Falls acts as a timepiece, allowing geologists to date the age of Niagara and the lakes.
  • The Falls eroded 3 to 4 feet annually until water diversion for hydroelectric power slowed the rate.
  • Despite the reduced erosion, the Falls still erode about half an inch monthly.
  • The Falls' retreat will eventually leave behind hotels and casinos as it moves towards Lake Erie.
  • Geologist Francine McCarthy dates the Great Lakes by examining clam shells carried over the Falls.
  • By carbon dating shells, McCarthy proves the Falls' presence in specific locations thousands of years ago.
  • The Falls' retreat carves the Niagara Gorge downstream, revealing the Lakes' historical locations.
  • A comet impact 12,900 years ago reshaped the Great Lakes region, leading to significant changes.
  • Evidence suggests a comet impact diverted the Great Lakes' flow from South to East.
  • The Great Lakes' evolution, impacted by various forces, continues to shape the region's geography.
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