Chapter 8.3

Question 1

Plate Tectonics

Answer 1

The theory concerning the movement of the continental plates

Question 2

Convection Curent

Answer 2

Circular movement that occurs when warmer, less dense fluid particles rise and cooler, denser fluid particles sink

Question 3

Continental Crust

Answer 3

the plates of the Earth’s crust that make up the land. 30-70km thick

Question 4

Oceanic crust

Answer 4

one of the types of crust that makes up the Earth’s outer layer. Oceanic crust is thinner than continental crust and made up of dense, heavy rocks such as basalt. On average they are 6km thick

Question 5

Boundaries

Answer 5

The edges of tectonic plates.

Question 6

Subduction

Answer 6

process in which two tectonic plates push against each other, and oceanic crust sinks below the less dense continental crust.

Question 7

Destructive Plate Boundaries

Answer 7

A convergent boundary where two plates collide.

Question 8

Constructive Plate Boundary

Answer 8

plate that creates new land from cooling magma.

Question 9

Laurasia

Answer 9

One of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago.

Question 10

Gondwanaland

Answer 10

one of the two smaller continents created when the supercontinent Pangaea broke apart about 200 million years ago.

Question 11

Hotspots

Answer 11

A localised place where an activity occurs.

Question 12

Why do the plates move?

Answer 12

The plates move because heat causes the partially molten rock in the mantle to expand and rise towards the surface. It spreads out, cools and falls back under the force of gravity. This creates a convection current that keeps the plates moving slowly.

Question 13

How is new oceanic crust made?

Answer 13

As the plates move apart, magma from the mantle rises. As it cools and solidifies in the sea water, it forms underwater volcanoes and creates new oceanic crust