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Flashcards in Week 8 Deck (23):
1

3 types of deformation

Elastic
Brittle
Ductile

2

Deformation

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

3

Ductile deformation

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

4

Brittle deformation

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

5

Joint

A fracture in rock along which there has been no displacement

6

Hanging wall / footwall

Hanging wall: rock surface immediately above a fault.

Footwall: rock surface below a fault

7

Fault scarp

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

8

Faults

Normal:
Reverse
Strike slip

9

What is rock deformation

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

10

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

Compressional : squeezes a rock mass- convergent

Tensional: pulls apart or elongates rock bodies- divergent

Shear: movement of one rock body past another- transform

11

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

Convergent

12

How is strain different from stress

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

13

How is brittle deformation different from ductile?

Brittle: stress breaks material when it exceeds the elastic limit

Ductile: flows in a solid state changes shape without fracturing

14

4 factors that affect rock strength

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

15

Distinguish between anticline and syncline

Anticline: compressional stress squeezes and makes arc like folds.

Syncline is opposite

16

How do the 3 faults differ from each other

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

17

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

J

18

How is a reverse fault different from a thrust fault

Thrust fault is a lower angle reverse fault

19

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

The side of the fault that moves as you face it

20

Normal fault

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

21

Reverse fault

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

22

Strike slip fault

A fault in which movement occurs horizontally

23

What type of stress causes folds

Compressional