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How are Rocks classified

How are Rocks classified. Chapter 7 Lesson 2 Pages 274-281. Igneous Rock p. 274. Igneous rock is rock that is formed when melted rock hardens. Magma is melted rock inside the Earth. Lava is melted rock at the Earth’s surface. Crystallization is the hardening of magma into rock.

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How are Rocks classified

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  1. How are Rocks classified Chapter 7 Lesson 2 Pages 274-281

  2. Igneous Rock p. 274 • Igneous rock is rock that is formed when melted rock hardens. • Magma is melted rock inside the Earth. • Lava is melted rock at the Earth’s surface. • Crystallization is the hardening of magma into rock.

  3. Igneous Rock p. 274Intrusive • Intrusive rock cools underground, deep within the Earth’s crust. • Characteristics of Intrusive igneous rock: • --Intrusive rock cools slowly. • --Intrusive rocks have large crystals. • --These rocks have coarse texture. • Examples: Granite and Diorite

  4. Igneous Rock p. 274Extrusive • Extrusive igneous rock is rock that cools on the Earth’s surface. • Extrusive rock cools quickly on the surface. • Extrusive rock has fine grains or even no crystals at all and • look glassy • Examples: Obsidian, Pumice and Rhyolite

  5. Sedimentary Rock p. 276 • Sedimentary rock is rock that forms when layers of sediment settle and bind together. • There are two main groups of sedimentary rock, Clastic and Chemical

  6. Sedimentary Rock p. 276Clastic and Chemical • Clastic-The word comes from the Greek work that means “broken”. • Process begins when rock is broken through weathering • Wind and water move sediment to new places, layers build up; minerals bind layers • Layers are pressed and cemented together. • Classified by size of particle.

  7. Sedimentary Rock p. 276Clastic and Chemical • Examples of Clastic Sedimentary Rock • Fine particles form shale • Medium particles form sandstone • Coarse pebble-sized particles with smooth edges form conglomerates.

  8. Sedimentary Rock p. 276Clastic and Chemical • Chemical Sedimentary rocks form when chemicals in water come out of the water (evaporate) and form solids • Example: Limestone (may contain fossils)

  9. Metamorphic Rock p. 278 • - Meta means “change”. • How it is made • Igneous or sedimentary rock is changed by • PRESSURE • HEAT – high temperature, very hot water • BOTH

  10. Metamorphic Rock p. 278 • Metamorphism is the process by which metamorphic rock is formed. • The main cause is high temperature-deep inside the Earth or in lava/magma • Minerals melt and then crystalize into new minerals

  11. Metamorphic Rock p. 278 • Regional Metamorphism take place over a large area • Mountain building • Contact metamorphism changes a smaller area by magma or lava touching rock and changing the rock that was touched.

  12. Metamorphic Rock p. 278 • Examples • Shale becomes SLATE • Slate becomes SCHIST • Schist becomes GNEISS • Limestone becomes MARBLE

  13. Uses of Rock p. 280

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