Chapter 10: Deformation (Strain) and Mountains

Question 1

Dip

Answer 1

Angle and direction of inclination of a surface

-Perpendicular to strike

Question 2

Strike

Answer 2

The direction of a line formed by the intersection of an inclined surface and a horizontal plane
-Perpendicular to dip

Question 3

Stress

Answer 3

Force applied; source is mantle convection
Compression –>
Shear –>
<–

Question 4

Strain

Answer 4

Deformation caused by stress

-Depends on type of material (brittle or ductile), Amount of stress (rate), and location (depth: pressure and temp)

Question 5

Brittle Materials

Answer 5

Elastic strain and Fracture

Question 6

Ductile Materials

Answer 6

Plastic Strain (flow) results in perm change of shape (folding)

• Slower stress, greater confining pressure, higher temp, and greater water content makes this more likely
• Plastic limit is when fracture occurs

Question 7

Folds

Answer 7

Result from compression and plastic strain

Question 8

Anticline

Answer 8

Folds where the oldest rocks are in the center at ground surface and all layers dip away from axis

Question 9

Syncline

Answer 9

Folds where the youngest rocks are in the center at ground surface and all layers dip toward axis

Question 10

Faults

Answer 10

Results from rupture and slip

Question 11

Dip-slip faults

Answer 11

Vertical movement

• Reverse: compressive stress, H up, F down
• Thrust fault: low angle (<45 degrees) reverse fault
• Normal: tensile stress, H down, F up

Question 12

Strike-slip fault

Answer 12

Horizontal movement; transform faults, shear stress

• Right lateral
• Left lateral

Question 13

Mountain Building

Answer 13

Orogenisis at convergent plate boundaries (growth of continents)