Crustal Deformation

1
Crustal Deformation

• How do rocks bend and break?
• What structures do they make?

2
Stress

• Forces placed on rocks that make them bend or
  break

3
Brittle vs. Ductile Deformation
Ductile Rocks bend
Brittle Rocks break
4
Ductile Structures
5
Fold - Syncline
Dome Rocks dip away from center
6
How Do Rock Structures Appear on the Surface??
Flat lying rock layers Topography makes the
surface patterns
Folds Structures make the surface patterns
7
Faults (Brittle Deformation)

• Three basic types of faults
• Normal extension
• Reverse compression
• Strike-slip umsideways

8
Normal Faults
Foot Wall
Hanging Wall
Commonly formed by tensional stress
9
Reverse Faults
Hanging Wall
Foot Wall
Commonly formed by compressional stress
10
Strike Slip Faults
Which way has the other side of the fault moved?
If to the right right-lateral strike-slip
fault
If to the left left-lateral strike-slip fault
Commonly formed by sheer stress
11
Normal Faults - Extension
12
Strike slip fault
- Shear stress
Right lateral
13
Rock beds are dipping away from the center
Dome
14
Anticline
Syncline
Compressional Stress
15
You Should Know

• Monoclines
• Strike and Dip
• These could appear on a exam or quiz.
• Read your book or find it in the notes!

16
Monoclines

• A one-limbed fold that is flat on the top bottom

17
Strike and Dip

• Orientation of rock layers Describes tilting
  and direction of tilting

strike
dip
dip