Download Aging Earth`s Layers

Aging Earth’s Layers
Lecture Today
Stress on Earth’s Crust
Tension, compression and shearing cause crustal deformation
Faults
Shearing
Causes transform or lateral faults
Compression
Causes reverse faults
Tension
Causes normal faults
May form fault bock mountains
Sharp angular and steep on one side
Gradual slope on other
Plateaus
Flat topped
May also be formed by lava flows
Formed by expansion of inner earth as increases in temperature
Stress on Earth’s Crust:
Folding
Caused by compression
Top of fold is anticline
Bottom is syncline
May cause folded mountains
Folding may be beneath surface
Fold or Fault
Stress may do either
Depends on
Temperature
Pressure
Type of rock
Time and duration of stress
Stress on Earth’s Crust:
Intrusions
Magma may push on layers of rock above it
Creates dome mountains
Black Hill in South Dakota
Absolute Dating
Radio Carbon dating
Uses radioactive elements
Change at predictable rates
Gives accurate age
Relative Dating
Uses comparison of ages
Looks at ages and events rock layers represent
Can only find sequence of events
Does not give actual age
Principle of Uniform Processes : Uniformitarianism
Opposes catastrophism
Processes changing Earth today changed Earth in past
Principle of Superposition
Bottom layers in geologic column are oldest
Relative Dating
Changes in order may be caused by
Folding
Faulting
Magma intrusions
Erosion- UNCOMFORMITY
Folds and Faults
May change order of rock layers in geologic column
Oldest to youngest order no longer applies
Relative Dating
Geologic History
Numbers rock layers from oldest to youngest
Includes a written paragraph explaining when folding, faulting,
erosion and magma intrusions occurred