Geologic Time

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Geologic Time
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Geologic Time

• Relative Time/absolute time
• Eons
• Eras
• Period
• Epoch

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Geologic time

• Relative Time - time scale based on
  relationships and order (what happens 1st, 2nd
  3rd and so on))

• Absolute time based on numerical proportions
• Measurable time
• days
• weeks
• months
• years
• centuries
• millennia

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• EONS
• The largest Unit of Geological time
• Geologic time has been divided into 4 Eons
• Hadean Eon
• Archeon Eon
• Precambrian Eon
• Phanerozoic Eon
• We live in the Phanerozoic Eon which dates back
  from 540 million years ago

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• Era
• A smaller division of an Eon
• Two or more geological unites comprise an era,
  which is hundreds of millions of years in
  duration.
• We live in the Cenozoic Era ( the era of
  mammals) it began 65 million years ago

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• Period
• The period is the basic unit of geological time
  in which a single type of rock system is formed,
  lasting tens of millions of years.
• Each Era can be broken into two or more periods
• We live in the Quaternary Period, 1.8 million
  years

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• Epoch
• An epoch is a division of a geologic period it
  is the smallest division of geologic time.
• We live in the Holocene Epoch 11,000 years ago

Hadean
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http//safeshare.tv/w/yRCIQInmNq
Go to video
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For the test!

• Explain the differences between absolute and
  relative time
• Explain Relative time and how it is broken down
  (at least two eras make an Eon and two periods
  form an Era etc.)
• Recognize two geological eons and what the
  differences is between the two
• Recognize the eras within each eon