Earth ScienceSarah Jones

www.wallibs.com

Earth’s Structure

www.edplace.com

Tectonic Plates

www.edplace.com

Igneous Rocks

science.nationalgeographic.com

Granite Pumice Obsidian

Igneous Rock Properties• Contain interlocking crystals – held together

strongly which makes the rock hard.• The crystals have a disorderly arrangement.• Crystal size depends on how quickly the rock

solidified.• They never contain

fossils.

news.nationalgeographic.com

Igneous Rock Formation• When magma cools above the Earth’s surface

it forms extrusive igneous rocks – the magma cools quickly and small crystals are formed.

• When magma cools below the Earth’s surface it forms intrusive igneous rocks – the magma cools slowly and large crystals grow as the magma solidifies.The Rock Cycle – Boardworks

http://0.tqn.com/d/geology/1/0/l/N/thundereggs.jpg

Basalt Columns

www.americansouthwest.net

Sedimentary Rocks

science.nationalgeographic.com

Limestone Sandstone Chalk

Sedimentary Rock Properties• Often have layers showing deposition at

different times.• Often have fossils trapped within them.• They consist of lots

of small grains and are often porous and crumbly.

www.iupui.edu

Sedimentary Rock Formation• Weathering creates small rock fragments

which are transported to the sea where they are deposited – sediment.

• Dead creatures may then become trapped – become fossils.

• The pressure of the layers above and the effects of salt cement the sediments together – happens over millions of years.

• Rocks formed – sandstone, mudstone and limestone.

• Sedimentary rocks can also be formed by precipitation.

• Certain minerals are dissolved in seas and lakes.• These dry up over millions of years.• The water evaporates and the

dissolved minerals precipitate.• Rocks formed –

limestone and chalkThe Rock Cycle – Boardworks

Metamorphic Rocks

www.nps.gov

MarbleSlate

Metamorphic Rock Properties• Often have layer structures of crystals – effect

of heat and pressure.• Usually denser and harder than sedimentary

rocks.• Sometimes show distortions caused by the

movements that leadto their formation.

Metamorphic Rock Formation• Formed by the effect of extreme pressure and

temperatures deep within the Earth.• This changes existing rocks so that new rocks

are formed.The Rock Cycle – Boardworks

http://23n58e.blogspot.com.au

The Rock Cycle

http://www.bbc.co.uk/bitesize/ks3/science/environment_earth_universe/rock_cycle/revision/10/

http://www.geologycafe.com/images/rock_cycle_big.jpg

Types of Rocks and Minerals• All rocks are made of two or more minerals.• Minerals are not made of rocks – minerals are

the same all the way through. http://www.rocksforkids.com/RFK/identification.html

http://0.tqn.com/d/chemistry/1/0/L/q/fluoritecrystals.jpg

Identifying Minerals

• Colour• Luster• Specific Gravity• Crystal Form• Cleavage• Fracture• Tenacity• Hardness• Transparency• Special properties - magnetism, chatoyancy, fluorescence,

odor, streak, burn test, conductivity.

http://australianmuseum.net.au/image/Pyrite-specimen

Some of Australia’s Mineral Resources

Iron Ore Bauxite Black Coal

Zinc Gold Nickel