Crustal Deformation

Question 1

Deformed (strained) rocks show…

Answer 1

tilted beds, metamorphic alteration, folding, and faulting, UNLIKE Undeformed rocks.

Question 2

Deformation can be classified as 3 types:

Answer 2

1. Displacement
2. Rotation
3. Distortion

Question 3

Displacement is…

Answer 3

A change in location

Question 4

Rotation is…

Answer 4

A change in spatial orientation

Question 5

Distortion is…

Answer 5

A change in shape

Question 6

Strain vs. Stress

Answer 6

Strain: 1. Stretching 2. Shortening 3. Shearing
Stress: 1. Tension 2. Compression 3. Shearing 4. Pressure

Question 7

What are the two behaviors when discussing deformation?

Answer 7

Brittle vs. Ductile

Question 8

occurs in the shallower crust, rocks break by fracturing

Answer 8

Brittle Deformation

Question 9

occurs at higher P and T conditions, which causes rock to deform by flowing and folding

Answer 9

Ductile Deformation - occurs at greater depth

Question 10

3 types of Dip Slips

Answer 10

Normal Faults, Reverse Faults and Thrust Faults (below 35 degrees)

Question 11

Strike-slip faults

Answer 11

• move sideways past each other

Question 12

Left Lateral movements

Answer 12

the opposite block moves to the left

Question 13

Right Lateral movements

Answer 13

The opposite block moves to the right

Question 14

What is the dominant cause of earthquakes?

Answer 14

Sudden movement at faults

Question 15

a line along which curvature is greatest

Answer 15

A hinge

Question 16

Limbs

Answer 16

are the less curved “sides” of a fold

Question 17

connects hinges of successive layers

Answer 17

Axial plane

Question 18

Anticline

Answer 18

a fold that looks like an arch.

Question 19

a fold that opens upward like a trough

Answer 19

syncline

Question 20

A nonplunging fold

Answer 20

has a horizontal hinge

Question 21

A plunging fold

Answer 21

has a tilted hinge

Question 22

a fold with the appearance of an
overturned bowl. Exposes older rocks in
the center.

Answer 22

A dome

Question 23

A basin

Answer 23

a fold shaped like an upright bowl. A basin exposes younger rocks in the center.

Question 24

planar rock fractures without any offset that develop from tensile stress in brittle rock.

Answer 24

Joints

Question 25

Viens are

Answer 25

Fractures filled with minerals

Question 26

What are the four causes of mountain building?

Answer 26

1. Continental collision 2. Convergent boundaries 3. Continental rifting 4. Delamination

Question 27

What is Isostasy?

Answer 27

Surface elevation is a balance between forces of gravitational attraction (which pulls plates into the mantle) and buoyancy (which floats lithosphere on top of the mantle)

Question 28

Off-scraped sediment

Answer 28

Accretionary prisms

Question 29

removal of deep lithospheric mantle can cause uplift

Answer 29

Delamination

Question 30

Ductile rock eventually flows out from beneath high mountains, which then settle downward like soft cheese. The upper brittle crust breaks into faults. This process, which leads to destruction of the mountains, is known as

Answer 30

orogenic collapse

Question 31

What is a craton?

Answer 31

continental crust that hasn’t been deformed in 1 Ga

Question 32

There are two cratonic provinces:

Answer 32

Shields and Platforms