Introduction to Geologic Time
(The Rock Record is Like a Chart Recorder Output)
[Not responsible for material in brown or blackitalics.
____ Ma Formation of Earth and Moon
Hadean Era begins
____ Archean Era begins (Oldest terrestrial rock)
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First Stromatolites (possible remains of life)
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First probable microorganisms
____ Proterozoic Era begins
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Oldest probable blue-green algae
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Oldest multi-celled organisms
____ Paleozoic Era begins (oldest skeletal remains--shells)
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First vertebrates--jawless fish
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First jawed fish
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First reptiles
____ Mesozoic Era begins (mass extinction)
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First dinosaurs
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First mammals
____ Cenozoic Era (Tertiary Period) begins (mass extinction)
____ Quaternary Period (Pleistocene Epoch) begins
____ Holocene Epoch begins (end of last Ice Age)
Two ways to view geologic time:
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_________ time: "older" vs. "younger" placed in order
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_________ time: "120 Ma" (Ma = million years; also m.y.)
The Geologic Time Scale (relative time)
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Eons, eras, periods, epochs
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Major divisions based on biologic events
The Geologic Periods
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Cambrian, Ordovician, Silurian, Devonian, Carboniferous,
Permian. Triassic, Jurassic, Cretaceous
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Can Oscar See Down Carl's Pants?
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E. Grossman (16JAN02)