30.2 The Precambrian and Paleozoic

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30.2 The Precambrian and Paleozoic
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PRECAMBRIAN TIME

• Not an official part of the geologic time scale,
  more a reference for the Archean (3.9 bya-2bya)
  and Proterozoic eons (lasted 2b.y.). Most of
  Earths history.

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Precambrian Time

• Evidence from Precambrian time periods
• Cratons the remains of Precambrian mountains
  and highlands. Located in shields (exposed
  cratons).
• The oregnies that produce the Precambrian
  cratons.
• Stromatolites mats of trapped sediments and
  cyanobateria that formed layered domes.

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Paleozoic Era

• Includes six periods
• Cambrian
• Ordovician
• Silurian
• Devonian
• Carboniferous
• Permian

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Paleozoic Era

• Cambrian Period
• Most common fossil is the trilobite. Ocean bound.
• Warm oceans covered most of what is N. America
• 120 animal types have been found.
• Photosynthetic algae

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Paleozoic Era

• Ordovician Period
• Graptolite invertebrates. (tiny, lived in
  colonies)
• Also lived in oceans
• Japan collide w/ N. America causing mountains in
  eastern part of US.
• Photosynthetic algae

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Paleozoic Era

• Silurian Period
• The appearance of land animals
• Appearance of land plants
• Shallow seas in N. America evaporated leaving a
  salt belt from New York to Lake Michigan.

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Paleozoic Era

• Devonian Period
• Age of fishes (jawless and jawed)
• Lungfish fossils (can come out of water)
• First forest
• Scaly bark trees
• Arcadian Orogeny (mountains from Newfoundland to
  Appalachians)

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Paleozoic Era

• Carboniferous Period (Mississippian/Pennsylvanian
  Periods)
• Crinoids and Foraminifera (invertebrates during
  the Mississippian period)
• Appearance of reptiles and true land vertebrates
• Left huge coal deposits in the US

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Paleozoic Era

• Permian Period
• Dry climate
• Pangea
• Sponges, corals and algae
• Permian Extinction (251 mya)
• 96 of all marine ssp/ 70-80 of land animals
• Climate change/Catastrophe or Increased volcanism
  believed to be cause.