Author :Sarah Jones
Number of slides:23
Content transcript :
1. Earth Science Sarah Jones
2. Earth’s Structure
3. Tectonic Plates
4. Igneous Rocks science.nationalgeographic.com
5. Granite Pumice Obsidian
6. 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
7. 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
8. Basalt Columns
9. Sedimentary Rocks science.nationalgeographic.com
10. Limestone Sandstone Chalk
11. 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.
12. 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.
13. • 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 chalk The Rock Cycle – Boardworks
14. Metamorphic Rocks
15. Marble Slate
16. 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 lead to their formation.
17. 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
18. The Rock Cycle
20. 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.
21. Identifying Minerals • Colour • Luster • Specific Gravity • Crystal Form • Cleavage • Fracture • Tenacity • Hardness • Transparency • Special properties - magnetism, chatoyancy, fluorescence, odor, streak, burn test, conductivity.
22. Some of Australia’s Mineral Resources Iron Ore Bauxite Black Coal
23. Zinc Gold Nicke