Week 8

Question 1

3 types of deformation

Answer 1

Elastic
Brittle
Ductile

Question 2

Deformation

Answer 2

How is it going to respond: elastic brittle ductile, resulting shape

General term for the process of folding faulting shearing compression, or extension of rocks as a result of various natural forces

Question 3

Ductile deformation

Answer 3

Folds: anticline syncline, monocline.

A type of solid state flow that produces a change in the size and shape of a rock body without fracturing. Occurs at depths where temperatures and confining pressures are high

Question 4

Brittle deformation

Answer 4

Deformation that involves fracturing of rock. Associated with rocks near the surface

Question 5

Joint

Answer 5

A fracture in rock along which there has been no displacement

Question 6

Hanging wall / footwall

Answer 6

Hanging wall: rock surface immediately above a fault.

Footwall: rock surface below a fault

Question 7

Fault scarp

Answer 7

A cliff created by movement among a fault. Represents the exposed surface of the fault prior to modification by weathering and erosion

Question 8

Faults

Answer 8

Normal:
Reverse
Strike slip

Question 9

What is rock deformation

Answer 9

Changes in the shape or position of a rock body in response to differential stress

Question 10

List the 3 types of differential stress/ changes they impart to rock bodies

Answer 10

Compressional : squeezes a rock mass- convergent

Tensional: pulls apart or elongates rock bodies- divergent

Shear: movement of one rock body past another- transform

Question 11

What type of plate boundary is most commonly associated with compressional stress?

Answer 11

Convergent

Question 12

How is strain different from stress

Answer 12

Strain is a change in shape caused by stress. (Resulting distortion )

Question 13

How is brittle deformation different from ductile?

Answer 13

Brittle: stress breaks material when it exceeds the elastic limit

Ductile: flows in a solid state changes shape without fracturing

Question 14

4 factors that affect rock strength

Answer 14

Temperature: heating makes it ductile/ malleable more brittle at low temps

Confining pressure: increases with depth, squeezes materials in all directions making them stronger and harder to break

Rock type: sedimentary is weaker

Question 15

Distinguish between anticline and syncline

Answer 15

Anticline: compressional stress squeezes and makes arc like folds.

Syncline is opposite

Question 16

How do the 3 faults differ from each other

Answer 16

Normal: Hanging wall block moves down relative to footwall

Reverse (thrust): hanging wall moves up.

Strike slip: parallel displacement ( moves out) right and left lateral

Question 17

Sketch each type of fault and indicate stress involved and motion of hanging and footwall.

Answer 17

J

Question 18

How is a reverse fault different from a thrust fault

Answer 18

Thrust fault is a lower angle reverse fault

Question 19

How do you figure out if a strike slip fault if right or left lateral

Answer 19

The side of the fault that moves as you face it

Question 20

Normal fault

Answer 20

A fault in which the rock above the fault plane has moved down relative to the rock below

Question 21

Reverse fault

Answer 21

Material above the fault plane moves up in relation to the material below

Question 22

Strike slip fault

Answer 22

A fault in which movement occurs horizontally

Question 23

What type of stress causes folds

Answer 23

Compressional