Earth Structure and Plate Tectonics

Question 1

Inner Core

Answer 1

Solid iron and nickel, higher temperature.

Question 2

Outer Core

Answer 2

Molten iron and nickel, lower temperature.

Question 3

What are the upper and lower mantles made of?

Answer 3

Iron, magnesium, and silica.

Question 4

What is silica?

Answer 4

A mix of silicon and oxygen.

Question 5

True or false: both layers of the mantle are molten and the rock in them moves quickly.

Answer 5

False, they are solid, and their rock moves slowly in response to convection currents.

Question 6

Which earth layer is the thinnest?

Answer 6

Crust

Question 7

How thick is the Earth’s crust?

Answer 7

Between 10 to 70 km thick.

Question 8

What are the types of rock plates that compose the Earth’s crust?

Answer 8

Oceanic and continental plates.

Question 9

How thick is oceanic crust?

Answer 9

~10 km

Question 10

Which type of crustal plate is thinnest?

Answer 10

Oceanic

Question 11

Which type of crustal plate is densest?

Answer 11

Oceanic

Question 12

Why is Oceanic crust denser than Continental?

Answer 12

Because it is composed largely of basalt and gabbro (igneous rocks), which are rich in heavy elements iron and magnesium.

Question 13

What makes up the core of continents?

Answer 13

Continental crust

Question 14

What is the average thickness of Continental crust?

Answer 14

35 km

Question 15

Why is Continental crust less dense than Oceanic?

Answer 15

Because it is largely composed of metamorphic rock and granite (an igneous rock), which are less dense than basalt and gabbro.

Question 16

What kind of plates make up the geosphere?

Answer 16

Crustal (continental and oceanic)

Question 17

Converging Plate Boundary

Answer 17

Where plates collide

Question 18

Subduction

Answer 18

A converging plate boundary where one of the plates is thrust underneath the other.

Question 19

Diverging Plate Boundary

Answer 19

Where plates pull apart from one another.

Question 20

Transform Plate Boundary

Answer 20

Where plates slide against one another.

Question 21

Where do continental volcanic arcs occur?

Answer 21

Near converging boundaries.

Question 22

Where do active continental margins occur?

Answer 22

At converging boundaries.

Question 23

Where do mid-ocean ridges occur?

Answer 23

At diverging boundaries.

Question 24

Where do passive continental margins occur?

Answer 24

Within a crustal plate.

Question 25

What is the basic concept behind Plate Tectonics?

Answer 25

Mountain ranges are created where the crust is bent up or broken, and where molten rock is injected into the crust and erupts onto the surface.

Ocean basins and large continental valleys are created where the crust is stretched, faulted, and down-dropped.

Question 26

Folding

Answer 26

When crust is bent upward.

Question 27

Faulting

Answer 27

When crust is broken,

Question 28

Magma

Answer 28

Molten rock

Question 29

Intrusion

Answer 29

When magma is injected into the crust.

Question 30

Volcanism

Answer 30

When magma erupts to the surface as lava from the crust.

Question 31

What causes plate movement?

Answer 31

Convection Currents

Question 32

Convection Currents

Answer 32

The vertical movement of gas, liquid, or some solids due to changing density.

Question 33

What are the 9 pieces of evidence for Plate Tectonics?

Answer 33

1. Geography
2. Rock and Sediment
3. Fossils
4. Magnetism and Rocks
5. Rock Magnetism and Age
6. Earthquake (patterns)
7. Faults and Folds
8. Volcanoes
9. Hotspot Tracks and Measuring Plate Motion