chapter 12

Question 1

What is the continental drift?

Answer 1

states that the continents drifted to their present location over millions of years.

Question 2

Who proposed the idea of the continental drift?

Answer 2

German scientist, Alfred Wegner.

Question 3

What is pangaea?

Answer 3

“pan” means all, “gaea” means earth. The idea of a supercontinent.

Question 4

What were the 4 evidences of pangaea?

Answer 4

similar rocks
mountain ranges
fossils
patterns of paleoglaciation

Question 5

What is paleoglaciation?

Answer 5

the evidence of ancient glaciers and rock markings left behind.

Question 6

What are tectonic plates?

Answer 6

large, movable slabs of rock that slide over a layer of partly molten rock

Question 7

What are volcanoes?

Answer 7

openings in earth’s surface that spews out gas, chunks of rock, and melted rock.

Question 8

What are earthquakes?

Answer 8

release of built-up energy that shakes the earth’s crust

Question 9

What is the mid-atlantic ridge?

Answer 9

a long mountain range running north to south down middle of atlantic ocean floor.

Question 10

What is magnetic reversal?

Answer 10

When Earth’s magnetic fields direction reverses

Question 11

What is paleomagnetism?

Answer 11

The study of magnetic properties of ancient rocks.

Question 12

What is magnetic stripping?

Answer 12

Indicates that new rock is being laid down on sea floor.

Question 13

What is sea floor spreading?

Answer 13

observed age of ocean rock, sediment thickness, and magnetic stripping.

Question 14

Who is Harry Hess?

Answer 14

american geologist who proposed sea floor spreading

Question 15

What is a spreading ridge?

Answer 15

a gap in sea floor that gradually widens as tectonic plates more apart.

Question 16

What is a hot spot?

Answer 16

an area where molten rock rises to earth’s surface

Question 17

Who proposed the idea of hot spot?

Answer 17

Canadian geologist J. Tuzo Wilson

Question 18

HOw are volcanic islands formed?

Answer 18

when tectonic plates pass over a stationary hot spot.

Question 19

What are the 4 layers of the earth?

Answer 19

crust
mantle
outer core
inner core

Question 20

Describe the crust.

Answer 20

made of solid, brittle rock.
contains granite and basalt.
5-60km thick.

Question 21

Describe the upper mantle.

Answer 21

made of partly molten rock.
contains magnesium and iron.
660km thick.

Question 22

Describe the lower mantle.

Answer 22

made of solid dense material.
contains magnesium and iron.
2225km thick.

Question 23

Describe the outer core.

Answer 23

made of liquid.
contains iron and nickel.
2270km thick.

Question 24

Describe the inner core.

Answer 24

made of solid.
contains iron and nickel.
1216km thick.

Question 25

What is the lithosphere?

Answer 25

a layer of earth made of the crust and upper mantle.

Question 26

What is the athenosphere?

Answer 26

partly molten layer in upper mantle

Question 27

What is mantle convection?

Answer 27

When hotter, less dense regions material in mantle rise, cool, and sinks again to be reheated.

Question 28

What is a spreading ridge/oceanic ridge?

Answer 28

Spreading centres in ocean

Question 29

What is a rift valley?

Answer 29

spreading centres on land.

Question 30

What is a ridge push?

Answer 30

the process where new material at a ridge or rift push old material away.

Question 31

What is subduction?

Answer 31

the action of one plate pushing below another.

Question 32

What is slab pull?

Answer 32

the pulling of a tectonic plate as its edge subducts deep into the mantle.

Question 33

What is a plate boundary?

Answer 33

where two tectonic plates are in contact

Question 34

What are 3 types of plate interactions?

Answer 34

divergent convergent transform

Question 35

What is divergent?

Answer 35

when plates are spreading apart.

Question 36

What is convergent?

Answer 36

when plates are colliding

Question 37

What is transform?

Answer 37

when plates are sliding past each other.

Question 38

What is oceanic-continental convergence?

Answer 38

when a dense oceanic plate slides beneath a continental plate, forming a trench, volcanoes, and mountain ranges.

Question 39

What is oceanic-oceanic convergence?

Answer 39

when one plate cools and subducts into the mantle and forms volcanic island arc.

Question 40

What is continental-continental convergence?

Answer 40

when rocky plates collide and forms mountain ranges when it's edges fold and crumple.

Question 41

What is a focus?

Answer 41

then location where an earthquake starts.

Question 42

What is the depth of a shallow focus?

Answer 42

0-70km

Question 43

What is the depth of an intermediate focus?

Answer 43

70-300km

Question 44

What is the depth of a deep focus?

Answer 44

greater than 300 km.

Question 45

What is a seismic wave?

Answer 45

a vibration that occurs when energy is released by an earthquake.

Question 46

What are the 2 body waves?

Answer 46

primary and secondary waves.

Question 47

What are primary waves?

Answer 47

the first to arrive travels at 6km/s can travel through solid, liquid, and gas

Question 48

What are secondary waves?

Answer 48

second to arrive travels at 3.5km/s can travel through solids, not liquids

Question 49

What are surface waves?

Answer 49

arrives last | rolls along the earth's surface

Question 50

What is magnitude?

Answer 50

a number that rates the strength of an earthquake

Question 51

What are 3 types of volcanoes?

Answer 51

composite shield rift eruptions

Question 52

What are composite volcanoes?

Answer 52

cone shaped magma is thick and traps gas frequently erupts

Question 53

What are shield volcanoes?

Answer 53

shield shaped thinner magma rarely erupts

Question 54

What are rift eruptions?

Answer 54

occurs when magma erupts through long cracks in the lithosphere. not explosive/violent but spews out a lot of lava.