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Year 8 - Science – Geology Mr. Cousins.  Igneous  Sedimentary  Metamorphic.

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Presentation on theme: "Year 8 - Science – Geology Mr. Cousins.  Igneous  Sedimentary  Metamorphic."— Presentation transcript:

1 Year 8 - Science – Geology Mr. Cousins

2  Igneous  Sedimentary  Metamorphic

3  Latin word ‘ignis’ – Meaning ‘fire’  What are they?  Formed by Lava (outside) or Magma (Inside).  Magma reaches the Earth’s surface when the volcano erupts.  Two types of Igneous: Intrusive and Extrusive

4 IntrusiveExtrusive Magma Lava ‘Forced In’ – Between layers of rock. Lava ‘Forced Out’ of volcano through an eruption. Cools below the surface.Cools above the surface. Large visible interlocking crystals.Crystals formed are small or non existent. Types of Intrusive Rocks: Granite – Types of Extrusive Rocks: Basalt-

5  USES OF IGNEOUS ROCKS Tools (Aboriginals) Gutters (Granite-Basalt) Lanes (Granite-Basalt) Roads (Basalt) Kitchen Benchtops (Granite) Gravestones (Granite) Railway Tracks (Basalt)

6  Latin word - ‘Setimendum’ – Meaning ‘Settling’ -‘Sedire’ – Meaning ‘to sit down’  Sedimentary rocks are made from the combination of sediment. Sediment is little pieces of broken down rocks, animals and plants. The sediment combines through a process known as lithification.

7  LITHIFICATION STAGES Stage 1 - Sediment Builds up and forms a layer on the bottom of a riverbed. - Pressure from the material above squeezes out any air or gaps that might exist in the sediment at the bottom of the layer. (The particles interlock) Stage 2 - Water Seeps through sediment carrying with it minerals that cement the particles together more strongly.

8  TYPES OF SEDIMENTARY ROCKS Name of RockMade From SandstoneSand MudstoneMud ConglomerateParticles of different sizes LimestoneRemains of sea organisms (Fish, Coral etc.) CoalCompressed plant material ChalkSkeletons of tiny sea animals

9  USES OF SEDIMENTARY ROCKS  Sedimentary rocks are easy to split and are often used as building or paving materials.  Limestone can be used as a building block or be ground to be a key ingredient in cement and other similar building materials.  Coal is burnt to provide power for electricity generation and heating.  Sandstone and blue stone are used in buildings.

10  Pressure cooker environment under the Earth’s Surface causes the rocks to change into new types of rocks.  Greek – ‘Meta’ – Meaning ‘Change’ - ‘Morphe’ – Meaning ‘Form’  All three types of rocks can be changed under the surface by heat and pressure.  These rocks are stronger then the original rock because they are fused. All the air is pushed out to make it stronger, like a snowball.

11 Original RockOriginal Rock Type Changed ByMetamorphic Rock LimestoneSedimentaryHeatMarble GraniteIgneousHeat/PressureGneiss ShaleSedimentaryPressureSlate MetamorphicHeat/PressureSchist SchiestMetamorphicHeat/PressureGneiss

12  Rocks are made but they are also weathered and eroded.  Weathering is when a rock is broken down into smaller particles such as pebbles, soil or sand.  This can happen in 3 Different ways:  Physical Weathering – Wind, water from waves and rivers, ice from glaciers and dramatic changes in temp can all wear down and crack the rock. (12 Apostles)  Chemical Weathering – Water and chemicals in the air (pollutants) react with rock and dissolve it.  Biological Weathering – Animals scratch at rocks to find food and build burrows. Plants also have there roots get into gaps and crack them. The particles are then carried away by animals, water and wind. (EROSION) When the particles settle the process starts again.


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