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Geologic Time Scale


Chapter 2, Section 3 Unit A Science 8 Messana What did you decide was more useful tree rings or ice cores? Why? Geologic Time Scale a timeline of Earth s ... – PowerPoint PPT presentation

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Title: Geologic Time Scale

Geologic Time Scale
  • Chapter 2, Section 3 Unit A
  • Science 8
  • Messana

  • What did you decide was more usefultree rings or
    ice cores?
  • Why?

Geological Time - really, really, really long!
  • Motion pictures are generally projected at 32
    frames per second. Therefore, each frame (image)
    is on the screen for only split second- let each
    frame represent 100 years.
  • Start movie at present and go back in time.
  • The Declaration of Independence would show up
    1/16 of a second into the movie.
  • The Christian era (BC-AD boundary) would be 3/4
    of a second into the movie.
  • The most recent Ice Age would be 7 seconds into
  • The movie would run about 6 hours before we got
    to the end of the Mesozoic era (extinction of the
  • We'd have to watch the movie for about 2 days to
    see the beginning of the Paleozoic era
    (macroscopic life).
  • The whole movie (to the beginning of geologic
    time on Earth) would be approximately 16 days

  • https//

A football field representing Geologic Time
Geologic Time Scale
  • Geologic Time Scale a timeline of Earths
    History divided into periods of time by major
    events or changes on Earth
  • What do we call these major events or changes?

  • Eon the longest division of geological time.
  • Era a major division of geological time an era
    is usually divided into two or more periods.
    (most recent eon 3 eras)
  • Period Each era is subdivided into a of
  • Epoch smallest division of time a subdivision
    of a period

Catastrophic Events
  • Catastrophic Events events that cause major
    destruction or change life completely
  • Examples
  • Mass extinctions
  • Ice Ages
  • Meteors
  • Pangaea
  • Major volcanic eruptions

EONS largest division of time
  • 1. Hadean
  • 2. Archean
  • 3. Proterozoic
  • 4. Phanerozoic
  • Eons 1-3 make up Precambrian Time (90 of
    Earths History)
  • Largest to Smallest amounts of TIME.
  • Eons -gt Eras -gt Periods -gt Epochs
  • Change in name is due major geologic or climatic

  • Most of Earths history
  • OR
  • 90 of Earths history
  • Lasted nearly 4 billion years of Earths 4.6
    billion years
  • Volcanic ash dust -gtclouds formed -gtrain
  • Single-celled micro-organisms in ocean at end
  • No animals!
  • No plants!
  • Turn Paper Please!!

Phanerozoic Eon
  • 544 million years ago present
  • Explosion of Life!
  • 3 Eras
  • Paleozoic Era Age of Amphibians
  • Mesozoic Era Age of Dinosaurs
  • Cenozoic Era Age of Mammals

Eras of Time Paleozoic Era Ancient
  • 544 mya 248 mya
  • All life in ocean until end
  • Fish developed
  • Reptiles, Insects, Ferns developed moving life
    onto land at end
  • Ends with a Mass Extinction (from a meteor
    strike?) kills 90 of all ocean species
  • EVOLUTION is beginning to emerge!

Mesozoic Era Middle
  • 248 mya 65 mya
  • PANGAEA- begins to break apart (about 200 million
    yrs ago!!!
  • Dinosaurs rule!
  • Small mammals, birds, flowering plants
  • Ends with Mass Extinction due to meteor strike
    off Mexico -gtdust cloud blocked sunlight, killed
    plant life and affected food chain

Cenozoic Era Recent
  • 65 mya Present
  • Large warm-blooded mammals, modern birds,
    flowering plants
  • Animals developed migration techniques
  • Tertiary Period
  • Quaternary PERIOD Past 2 million yrs
  • Ice ages
  • 1st modern human fossils 100,000 yrs old
  • Humans are 7 seconds of 12 hour clock!! 0

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Reminder Theory of Uniformitarianism
  • Earth is constantly changing due to the same
    basic forces
  • EX Slow erosion, plate movement
  • Fast volcano, earthquake