Presented By: Dave Heeney, Jeff Lawik, and Wojtek Maroszek

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Ice Ages

• Presented By Dave Heeney, Jeff Lawik, and Wojtek
  Maroszek

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In The Next 10 Minutes You Will Learn

• What an Ice Age is
• What causes them
• Where they begin
• Potential destruction
• Frequency of occurrence
• Past events

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What Is An Ice Age?

• A period in history when glaciers have covered a
  significant portion of the earths surface.
• Also describes a time with low amounts of
  insulation of heat resulting in significant
  cooling of the atmosphere.

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What Causes Ice Ages?

• The Milankovitch Astronomical Theory explains
  regular climatic changes.
• During a certain point in time, at 60 degrees to
  70 degrees north, the Arctic Circle does not
  receive adequate amounts of radiation.
• This happens every 100,000 years and lasts a very
  long time causing polar temperatures to
  dramatically decrease allowing glaciers to
  rapidly expand.

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Other Contributing Factors

• Sea levels have been proven to be a contributing
  factor.
• When glaciers form over the ocean, the water
  level drops.
• Water levels drop, more land is exposed, causing
  temperatures to decrease.
• Temperature decrease due to the lack of heat
  sinks on the earth.

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Where Do Glaciations Begin?

• Typically, Ice Ages would begin to be evident in
  places with high amounts of glaciations,
  particularly the north and south poles.
• The actual physical glaciations would be evident
  at the poles, but also a global decrease in
  temperature would be noticed.

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Potential Destruction

• Ice Ages would slowly cover land and "devour"
  resources as well as anything in its path.
• Ice Ages, or glaciations, can not necessarily be
  referred to as destruction.
• Glaciers scrape the land and tear holes into the
  Earths surface, resulting in very important
  geological features like the Great Lakes.

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Frequency Of Event

• The frequency of ice ages is not for certain.
• It can be estimated based upon the previous
  activity of the Earth's history.
• Each Ice Age, or glaciation, begins slowly and
  can take up to 80,000 years to reach its maximum
  extent.
• A rapid melting of the glaciations begin,
  followed by the next accumulation of glaciations,
  only 10,000 to 20,000 years after the climax of
  the previous glaciation or Ice Age.

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Past Events

• Proterozoic era about 800 and 600 mill years ago
• Pennsylvanian and Permian Eras about 350 and 250
  million years ago
• Neogene era to Quaternary era, only 4 million
  years ago

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Important Facts

• If the term Ice Age is to refer to long,
  generally cool intervals when glaciers advance
  and retreat, then we are still in one today.
• Geological evidence indicates the global climate
  has been naturally cooling for the last several
  thousand years.

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Important Facts
In the distant future, Earth may once again look
like this
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This Concludes Our PresentationOn Ice Ages