Science 8 - Movement Of The Earth's Crust

Front 1

Crust (5)

Back 1

- outermost layer
- 5-1,000 km thick
- solid, rocky material that floats on mantle

Oceanic- mostly basalt
8km thick
Continental- mostly granite
32km thick
up to 70km thick beneath mountains

Front 2

Mantle (6)

Back 2

- layer of earth between crust & core
- 2,900km thick
- extremely thick layer made of molten rock
- upper mantle like hot, thick tar
- exhibits plasticity when molten rock bends & flows
- convection currents exist

Front 3

Core (2)

Back 3

Outer Core- liquid, mostly iron

Inner Core- dense ball of solid material

Front 4

What is stress? (3)

Back 4

- forces that act on the earth
- cause deformation
- as rocks undergo stress, it slowly changes shape & volume

Front 5

What is deformation?

Back 5

- breaking, tilting, and folding of rock caused by stress

Front 6

What is compression? (2)

Back 6

- causes reverse fault
- squeezes rocks of crust, causing them to be pushed higher up/deeper down

Front 7

What is tension? (2)

Back 7

- causes normal fault
- pulls on rocks causing them to stretch over a large area

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What is shearing? (2)

Back 8

- causes strike-slip fault
- sliding of rock horizontally past each other

Front 9

What is a fracture?

Back 9

- cracks in rock caused by stress

Front 10

What is a fault?

Back 10

- break/crack along which rocks move

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Hanging Wall

Back 11

- block of rock above fault

Front 12

Foot Wall

Back 12

- block of rock below fault

Front 13

What is a normal fault? (2)

Back 13

- caused by tension
- hanging wall moves down relative to foot wall

Front 14

What is a reverse fault? (2)

Back 14

- caused by compression
- hanging wall moves up relative to foot wall

Front 15

Thrust Fault (3)

Back 15

- type of reverse fault
- caused by compression
- hanging wall slides over and on top of foot wall

Front 16

What is a lateral/strike-slip fault? (2)

Back 16

- caused by shearing
- fault along which blocks move horizontally past each other

Front 17

Fault-Block Mountain

Back 17

- mountains formed by blocks of rock uplifted by normal faults

Front 18

Rift Valley

Back 18

- landform created when the block of rock between 2 normal faults slides down

Front 19

What is an anticline?

Back 19

- upward fold in rock

Front 20

What is a fold?

Back 20

- bend in a rock caused by stress

Front 21

What is a syncline?

Back 21

- downward fold in rock

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What are the four factors that determine whether a rock will fault/fold?

Back 22

1. temperature
2. pressure
3. rock type
4. how stress is applied

Front 23

Plateau

Back 23

- landform formed when large area of flat land is raised above sea level

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Moho

Back 24

- transitional area that lies in boundary of crust & mantle of earth

Front 25

Domes

Back 25

- landform fomed by a raised area in a spherical/circular shape

Front 26

Isostasy (3)

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- balancing of downward force of earth & upward force of mantle
- if material is added to crust, that area will float lower on mantle
- if material is removed, that area will float higher on mantle

Front 27

Lithosphere (4)

Back 27

- part of earth's surface covered by land
- outermost layer of earth
- made up of crust & rigid upper portion of mantle
- divided into sections called tectonic plates

Front 28

Athenosphere (3)

Back 28

- layer of earth directly below lithosphere
- plates of lithosphere float on this layer
- consists of molten material that flows slowly

Front 29

Mesosphere

Back 29

- layer that extends from bottom of asthenosphere to core