Principal of Superposition

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Principal of Superposition
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Original Horizontality
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Principle of Original Horizontality
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Principal of Cross-cutting relationships
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UNCOMFORMITY- a buried surface of erosion
separating two rock masses. This represents agap
in geologic time...
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Three Types of Unconformities

• Unconformities
• are buried eroded surfaces which represent gaps
  in geologic time. Unconformities form when land
  above sea level is eroded and sinks. Sediment is
  then deposited over the eroded surface.

• Three types of unconformities include

1) Angular Unconformity 2) Disconformity 3)
Nonconformity
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Angular Unconformity

• Compressional forces cause sedimentary layers to
  fold as the layers uplifted.
• The folded layers are eroded and sinks where
  sediment is deposited over the erosional
  surface.
• Rock layers below the erosional surface are
  inclined at an angle to the erosional surface
  and layers above.

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STEP 1
STEP 2
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STEP 3
STEPS 4-6
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Disconformity

• Rock layers above and below the erosional
  surface are parallel.

Sinking
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Nonconformity

• The eroded surface of metamorphic or plutonic
  igneous rocks are buried by younger sedimentary
  layers.

sinking
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Unconformities
3 types of unconformities are seen
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Practice what happened here?
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(No Transcript)
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Superposition
Angular unconformity
Cross-cutting
inclusions
Cross-cutting
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Describe the steps that this cross-section went
through before it looked like this.