Features of sedimentary, metamorphic and igneous rocks.

3. Sedimentary rocks Sandstone Conglomerate Limestone

4. Metamorphic rocks Slate Marble Quartzite

5. Igneous rocks Granite Pumice Obsidian

6. Summary Sometimes have tiny crystals, no fossils, always hard and sometimes arranged in layers Other rocks were acted on by heat and pressure over a long time (e.g. marble, slate) Contain crystals, very hard, never contain fossils Liquid rock (magma or lava) cooled down and turned back into a solid (e.g. basalt, granite) Usually soft, can contain fossils, easily eroded Small pieces of sediment were stuck together by salt and pressure from rocks above (e.g. sandstone, limestone, chalk) Appearance How they were formed Sedimentary, igneous or metamorphic?

7. Summary Sometimes have tiny crystals, no fossils, always hard and sometimes arranged in layers Other rocks were acted on by heat and pressure over a long time (e.g. marble, slate) Contain crystals, very hard, never contain fossils Liquid rock (magma or lava) cooled down and turned back into a solid (e.g. basalt, granite) Usually soft, can contain fossils, easily eroded Small pieces of sediment were stuck together by salt and pressure from rocks above (e.g. sandstone, limestone, chalk) Appearance How they were formed Sedimentary, igneous or metamorphic?

9. Sedimentary rocks How sedimentary rocks are formed: 1) Weathering 2) Transportation 4) Burial 3) Deposition

10. Metamorphic rocks Metamorphic rocks are formed by the combined effect of heat and pressure on other rocks: Pressure from rocks above… … and heat from magma nearby

11. Igneous rocks Igneous rocks are formed when lava or magma cools down and solidifies If the lava or magma cools QUICKLY it has SMALL crystals If the lava or magma cools SLOWLY it has BIG crystals