The Rock Cycle and Rocks
- 1. RocksAll You Need To Know
- 2. Rock TypesThree Main Types of Rocks:IgneousSedimentaryMetamorphic
- 3. Igneous RocksFormed from magma (molten rock below earth’s surface) or lava (molten rock above earth’s surface).When molten rock crystallizes (cools/hardens), Two types of Igneous Rocks can Form:Intrusive: cool slowly inside earth’s crust allowing for large crystals to growExtrusive: cool quickly above earth’s surface not allowing for any crystals to grow or allowing for very small crystals to growExamples include:Granite and gabbro (intrusive) and basalt and obsidian (extrusive)
- 4. Sedimentary RocksFormed from pieces of other rocks (sand, shells, pebbles etc…) i.e. sediment that gets glued and compacted together.Different Types Include:Clastic – made from other piecesExamples sandstone, conglomerate, shaleChemical – precipitates or evaporatesExample rock salt (halite)Organic – formed from once living thingsExamples coal, limestoneFossils are found in sedimentary rocks.
- 5. Metamorphic RocksFormed from intense heat and pressure.Two Types:Foliated: ribbonlike/banded layersExamples slate, phyllite, schist, gneissNon-foliated: crystals (no banding)Examples quartzite, marbleMay have shiny crystals as well as the minerals in the rock change due to the intense heat and pressure.
- 6. Key Identifying CharacteristicsIgneous Rocks:Gas bubbles holes created from trapped gasGlassy surface shiny smooth surface from quick cooling rocksCrystals small, flat surfaces that are shiny or sparklySedimentary Rocks:Sand or pebbles individual stones, pebbles, or sand grains visible in the rockFossilsI imprints of shells, insects, leaves etc…Metamorphic Rocks:Ribbonlike layers wavy or straight stripes/bands of different colors in the rock
- 8. Click the Picture Below
- 9. How Rocks ChangeRocks change due to various processes.Processes Include:Heat and PressureMelting and CoolingWeathering and ErosionCompacting and Cementing
- 10. Heat and PressureHeat from the earth’s interior can melt rock and pressure from overlying rock can also morph (change) rocks from one type to another.Heat increases dramatically the deeper a rock gets pulled under the earth’s surface – prior to melting a rock can change chemically to become another rock.Pressure from overlying rock also can change a rock chemically into another type of rock.Heat and pressure work together and this is known as metamorphism thus creating metamorphic rocks.
- 11. Click Below and Press Start
- 12. Melting and CoolingMelting:Temperatures between 600 and 1300 degrees Celsius (1100 – 2400 degrees Fahrenheit) melt rock and turn it into magmaCooling:any rock that forms from cooling magma is an igneous rockTwo Types of Igneous Rock:Intrusive form from slowly cooling magma inside earthExtrusive form from quickly cooling lava above/on earth’s crust
- 13. Click Below and View Each Animation
- 14. Weathering and ErosionWeathering:the breaking apart or wearing down of rock due to water, wind, gravity, temperatures, and other elements at the earth’s surface.Creates sediments.Erosion:Transportation of weathered material via water, wind, or gravity.
- 15. Compacting and CementingCompacting:Sediment formed from weathering and erosion accumulates (is deposited/left behind) in oceans, lakes, and valleys this allows for layers of sediment to build upEach layer presses down on the layer below it, thus compacting (pushing down on) bottom layers.Cementing:When water passes through spaces in between particles of sediment this helps cement the particles together forming sedimentary rock
- 16. Click Below and View Each Animation
- 17. Test Your Knowledge Click and Complete
- 18. The Rock CycleJames Hutton (1726-1797) is attributed with the concept of the rock cycle.Main Idea of Rock Cycle:Rocks are continually changing from one type to another and back againElements that make up rock aren’t destroyed or created, they are just being recycled
- 19. Click and Explore the Rock Cycle by Rolling Your Mouse Over It
- 20. Click and Test Your Rock Cycle Knowledge
- 21. Click Below and Test Your Rock Skills