Quiz over Chapter 10 Flashcards Preview

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Flashcards in Quiz over Chapter 10 Deck (41):
1

Deformation

refers to all changes in the shape or position of a rock body in response to stress

2

Rock or geologic Structures

features that result from forces generated by the interactions of tectonic plates
(includes folds, faults, and joints)

3

Stress

the force that deforms rocks

4

Magnitude

a function of the amount of force applied to a given area

5

When stresses on a rock exceed its strength....

the rock deforms by flowing, folding, fracturing, or faulting

6

Confining pressure

stress applied to uniformity in all directions
squeezes rocks, making them stronger and harder to break

7

differential stress

Stress applied unequally in different directions

8

Types of Stress

Compressional
Tensional
Shear

9

Compressional Stress

squeezes a rock and shortens a rock body

10

tensional stress

pulls apart a rock unit and lengthens it

11

Shear stress

Produces a motion similar to slippage that occurs between individual playing cards when the top of the stack is moved relative to the bottom

12

Strain

change in shape of a rock caused by differential stress
strained bodies lose their original configuration during deformation

13

Elastic deformation

rock returns to nearly its original size and shape when the stress is removed

14

ductile deformation

bends

15

brittle deformation

breaks

16

Temperature

Higher temp deform by ductile deformation {deep}
Cooler rocks form by brittle deformation {on surface or high up in crust}

17

Factors that affect rock strength

Rock type
Time
Temperature
Pressure

18

Rock type

Crystalline igneous rocks generally experience brittle deformation, whereas sedimentary and metamorphic rocks experience ductile deformation

19

Time

forces applied over a long period of time generally result in ductile deformation

20

Joints

cracks in the rocks resulting from the rock being stretched and pulled apart
created columns

21

Faults

fractures in the rocks where rocks on one side of the fault are displaced relative to the rocks on the other side of the fault

22

Folds are evidence

that rocks can bend without breaking
result of deformation in high temp high pressure environments

23

Most folds are

result from compressional stresses that result in a shortening and thickening of the crust

24

Anticlines

upfolded or arched sedimentary layers
Oldest strata in the center

25

Synclines

downfolded or troughs of rock
youngest strata are in the center

26

symmetrical

the limbs of the fold are mirror images of each other

27

asymmetrical

the limbs of the fold are not identical
-Overturned : one or both limbs are titled beyond vertical
-Plunging- the axis of the fold penetrates the ground

28

Domes

upwarped circular features

29

Basins

Downwarped circular features
looks like a bowl

30

Monoclines

large, steplike folds in the otherwise horizontal sedimentary strata
Fold with one limb

31

Strike and Dip

sedimentary rocks that are inclined or bent indicate that the layers were deformed folowing deposition

32

Strike

Compass DIRECTION of the line produced by the intersection of an inclined rick layer or fault in a horizontal plate

33

Dip

ANGLE OF INCLINATION of the surface of a rock unit or fault measured from a horizontal plane

34

Faults

Fractures in rocks where displacement happened

35

slickenslide

polished smooth surfaces that happen from movement along a fault

36

Dip-Slip Fault

when movement is parallel to inclination
Moves up and down along dip
produces fault scarps

37

Normal Dip-Slip faults

hanging wall moving DOWN relative to the footwall {Tension}
Reverse fault moves up the footwall {Pressure}

38

horst

Uplifted blocks

39

grabens

Down-dropped blocks

40

Strike slip faults

moves horizontal and parallel to the strike - side by side

41

Oblique-slip faults

both a strike-slip and dip-slip movement