Plate Tectonics- Basics

Question 0

The inner core contains…

Answer 0

Nickel and iron

Question 1

Name the earths structure from inner core to crust, and name whether each layer is solid, semi-molten, molten or rigid.

Answer 1

Inner core (solid)
Outer core (semi-molten)
Mantle (molten)
Asthenosphere (semi-molten)
Lithosphere (rigid mantle and crust)

Question 2

The outer core contains…

Answer 2

Iron and nickel

Question 3

Two types of crust…

Answer 3

Continental

Oceanic

Question 4

Oceanic crust is… (thickness, density)

Answer 4

Thinner, 6-10km thick, but more dense

Question 5

Continental crust is… (thickness, density)

Answer 5

Thicker, 30-70km, less dense

Question 6

What is the lithosphere?

Answer 6

Rigid upper mantle between asthenosphere and crust.

Question 7

What is the asthenosphere?

Answer 7

Semi-molten section of mantle.

Question 8

Mantle contains…

Answer 8

Silicate rocks

Question 9

The lithosphere is divided up into lots of sections called…

Answer 9

Tectonic plates

Question 10

The plates move due to _ _ _ _ _ _ _ _ _ _ within the _ _ _ _ _ _ _ _ _ _ _ _ _

Answer 10

Convection currents

Asthenosphere

Question 11

The place where two plates meet is called a…

Answer 11

Plate boundary or margin

Question 12

Who came up with the Theory of Plate Tectonics?

Answer 12

Alfred Wegener

Question 13

Alfred Wegener thought that…

Answer 13

The continents had drifted apart over millions of years from a Supercontinent called Pangaea.

Question 14

What evidence did Wegener provide to support his theory?

Answer 14

The shapes of the East coast of South America and the West coast of Africa fit together.
Fossils, plant and rock types found on those coastlines suggesting they were once joined.

Question 15

Why was Wegener’s theory disregarded by the geoscientific community?

Answer 15

He could not provide an explanation as to why the continents were drifting apart.

We obviously now know good old Alfred was barking up the right tree, and that convection within the mantle causes continental drift.

Question 16

Where is new crust created?

Answer 16

When plates move apart- divergent or constructive boundaries

Question 17

What is the name for when divergent (constructive) margins occur below water?

Answer 17

Sea-floor spreading

Question 18

When did Alfred Wegener propose his theory?

Answer 18

1912

Question 19

What did Bruce Heezen and Marie Tharp discover?

Answer 19

The mid-Atlantic ridge

Question 20

Palaeomagnetism involves…

Answer 20

Mapping the magnetic fields of the earths surface.

Question 21

How often do the earths poles switch/ reverse?

Answer 21

Every 200,000 years or so, the earth’s magnetic field reverses polarity (N and S switch)

Question 22

What does Palaeomagnetism provide evidence for?

Answer 22

Sea floor spreading.

Question 23

Example of constructive plate margin in the ocean…

Answer 23

Mid-Atlantic ridge

Question 24

Difference between mid-ocean ridge and Rift Valley…

Answer 24

Mid-ocean ridge: plates diverge underwater

Rift Valley: plates diverge beneath land

Question 25

Example of rift system…

Answer 25

East African Rift System (stretching from Mozambique to the Red Sea)

Question 26

What occurs at constructive, destructive and conservative plate margins: earthquakes, volcanoes, or both?

Answer 26

Constructive: both
Destructive: both
Conservative: only earthquakes