Crustal Deformation Flashcards
Deformed (strained) rocks show…
tilted beds, metamorphic alteration, folding, and faulting, UNLIKE Undeformed rocks.
Deformation can be classified as 3 types:
- Displacement
- Rotation
- Distortion
Displacement is…
A change in location
Rotation is…
A change in spatial orientation
Distortion is…
A change in shape
Strain vs. Stress
Strain: 1. Stretching 2. Shortening 3. Shearing
Stress: 1. Tension 2. Compression 3. Shearing 4. Pressure
What are the two behaviors when discussing deformation?
Brittle vs. Ductile
occurs in the shallower crust, rocks break by fracturing
Brittle Deformation
occurs at higher P and T conditions, which causes rock to deform by flowing and folding
Ductile Deformation - occurs at greater depth
3 types of Dip Slips
Normal Faults, Reverse Faults and Thrust Faults (below 35 degrees)
Strike-slip faults
- move sideways past each other
Left Lateral movements
the opposite block moves to the left
Right Lateral movements
The opposite block moves to the right
What is the dominant cause of earthquakes?
Sudden movement at faults
a line along which curvature is greatest
A hinge