Types of Rocks

• There are three main types of rocks:

1.1. IgneousIgneous - formed when molten rock cools.

2.2. SedimentarySedimentary – formed by the “cementing together” of small grains of sediment.

3.3. MetamorphicMetamorphic – rocks changed by the effect of heat and pressure.

Igneous Rocks

• These are rocks formed by the cooling of molten rock (magma.)

magma

volcanoMagma cools and solidifies forming igneous rocks

Sedimentary Rocks• Sedimentary Rocks are rocks

formed when particles of sediment build up and are “cemented together” by the effect of pressure and minerals.

sea

Fragments washed to the sea

Sedimentary rocks

Rocks are brokenup by the actionof weather

Gettin

g o

lder

Metamorphic Rocks

• Metamorphic rocks are formed by the effect of heat and pressure on existing rocks.

• This can greatly affect the hardness, texture or layer patterns of the rocks.

Magma

metamorphic

rockforming

here

heat

Pressure from surface rocks

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