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Earth’s crust is the brittle shell of a deep layer of hot rock

called the mantle. This is moving very slowly, driven by

heat generated deep within the planet. The movement has

made the crust crack into separate plates, which are being

pulled apart in some places and pushed together in others.

As they move, the plates make oceans larger or smaller,

and carry continents around the globe.

Plate tectonics

◀ KIT OF PARTS

There are 15 large tectonic plates, and almost

40 smaller ones. They form the ocean floors,

and some of the largest carry continents.

Continental plates are made of thicker, but

lighter, rock than the ocean floors. The oceanic

parts of the plates are always changing size

and shape, but the continents, although

moving, do not change

so much.

Eurasian plate

Australian plate

South American

plate

Pacific plate

Arabian

plate

Philippine

plate

Antarctic

plate

Cocos

plate

Indian

plate

Scotia

plate

African plate

Nazca plate

North American

plate

Caribbean

plate

PLATE BOUNDARIES

At some plate boundaries the plates are

pulling apart, while at others they are pushing

together. There are also places where one plate

is sliding against another. All these movements

cause earthquakes, and many boundaries are

dotted with volcanoes.

1

2

Divergent boundaries

These

occur where plates are pulling apart,

usually on ocean floors. This allows hot

mantle rock to erupt in the rift zone and

solidify as new ocean floor.

Convergent boundaries

These are found where one plate

grinds beneath another. Ocean

floors always slide under continents,

pushing up mountain ranges.

Rift zone dotted

with underwater

volcanoes

Erupting lava forms

ridges of solid rock

Edge of

continent

rucked up

to form

mountains

Plate slides on

mobile layer at

top of mantle

Friction melts

rock, making

it erupt as

volcanoes

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