Chapter 11, test 2: crustal deformation adn mountain building Flashcards Preview

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Flashcards in Chapter 11, test 2: crustal deformation adn mountain building Deck (32)
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1
Q

deformation

A

a general term that refers to all changes in the original form and/or size of a rock body.

2
Q

stress

A

the forces that deform rock

compressional stress, and tensional stress

3
Q

compressional stress

A

stress that squeezes and shortens rock mass

4
Q

tensional stress

A

stress that pulls apart or elongates a rock mass

5
Q

elastic deformation

A

like a rubber band the rock will return to nearly its original size and shape when stress is removed

6
Q

brittle deformation

A

when the limit of rock strength is surpassed the rock fractures
low temp

7
Q

ductile deformation

A

solid state flow (like water or taffy) that produces a change in shape without fracturing.
high temp

8
Q

factors that influence the strength of a rock

A

temperature
confining pressure
rock type
time

9
Q

temperature

A

high temp causes ductile deformation

low temp causes brittle deformation

10
Q

confining pressure

A

greater pressure causes ductile deformation

11
Q

rock type

A

sedimentary rocks and foliated metamorphic rocks deform by ductile deformation.
igneous tend to deform by brittle deformation

12
Q

time

A

when techtonic forces are applied slowly over a long time, rocks display ductile deformation

13
Q

folds

A

rocks bent in a series of waves
most folds result form compressional forces that shorten and thicken crust
types: anticline, syncline

14
Q

anticline

A

up folded or arched rock layers

15
Q

syncline

A

down folded rock layers

16
Q

symmetrical

A

limbs mirror images

17
Q

asymmetrical

A

limbs are not mirror images

18
Q

overturned

A

one limb is tilted beyond the vertical

19
Q

faults

A

fractures or breaks in rocks along which appreciable displacement has taken place

20
Q

dip slip fault

A

movement along the inclination (dip) of fault plane

2 types: normal and reverse/thrust

21
Q

hanging wall

A

the rock above the fault surface

22
Q

footwall

A

the rock below the fault surface

23
Q

normal dip slip fault

A

hanging wall moves down
associated with fault block mountains
caused by tensional forces <>

24
Q

reverse dip slip fault

A

hanging wall moves up
caused by compressional stress ><
dips greater than 45 degrees

25
Q

thrust dip slip fault

A

hanging wall moves up
caused by compressional stress ><
dips less than 45 degrees

26
Q

megathrust earthquakes

A

due to shallow dip of the plate boundary large sections tend to get stuck
these are most powerful earthquakes, a lot of tension builds up

27
Q

strike slip fault

A

slide past each other
dominant displacement in horizon
often associated with plate boundaries

28
Q

joints

A

fractures along with no appreciable displacement has occurred (no movement)
example is arches national park

29
Q

orogenesis

A

refers to processes that collectively produce mountain belts

example: laramide orogeny produced the rocky mountains

30
Q

continental volcanic arc

A

oceanic-continental crust convergence

31
Q

volcanic island arcs

A

oceanic-oceanic crust convergence

32
Q

continental collisions

A

continental-continental crust convergence