Diese Präsentation wurde erfolgreich gemeldet.
Die SlideShare-Präsentation wird heruntergeladen. ×

Rocks Science..232323232323232323

Nächste SlideShare
Geology Test Revision
Geology Test Revision
Wird geladen in …3

Hier ansehen

1 von 45 Anzeige

Weitere Verwandte Inhalte

Diashows für Sie (20)


Rocks Science..232323232323232323

  1. 1. What is a Rock? • Naturally-occurring mixtures of minerals, mineraloids, glass or organic matter.
  2. 2. What is a Rock? • Rocks are divided into 3 groups based on how they were formed: •IGNEOUS •SEDIMENTARY •METAMORPHIC
  3. 3. What is the difference between a rock and a mineral? • Rocks are made up of ONE or MORE minerals.
  4. 4. Once a rock is formed, does it stay the same rock forever? • NO!
  5. 5. • Rocks are continually changed by many processes, such as weathering, erosion, compaction, cementation, melting, and cooling • Rocks can change to and from the three types
  6. 6. What is the process through which rocks change? • The Rock Cycle—earth materials change back and forth among the different types of rocks
  7. 7. • No set path a rock takes to become another kind of rock
  8. 8. IGNEOUS SEDIMENTARY METAMORPHIC Weathering, Erosion, Compaction, Cementation Recrystallization Weathering, Erosion, Compaction, Cementation Recrystallization Melting, Solidification Melting, Solidification
  9. 9. How are rocks redistributed? • The core, mantle, & crust are one giant rock recycling machine
  10. 10. ***Watch the Rock Cycle by Brainpop 1. What do igneous rocks form from? 2. What kind of rock is sandstone? 3. What are metamorphic rocks formed by?
  11. 11. • “Ignis” = Latin for “fire” • Formed from the cooling of either magma or lava • The most abundant type of rock • Classified according to their origin and composition
  12. 12. ORIGIN— Where rocks are formed • Below ground = from magma (intrusive igneous rock) • Usually have LARGE crystal grains (they cooled slowly)
  13. 13. Some have large & small crystals (called porphyritic)
  14. 14. • Above ground = from lava (extrusive igneous rock) • Usually have SMALL or NO crystals (they cooled too quickly)
  15. 15. Peridotite: Intrusive or Extrusive? Why?
  16. 16. Granite: Intrusive or Extrusive? Why?
  17. 17. Porphyry: Intrusive or Extrusive? Why?
  18. 18. Obsidian: Intrusive or Extrusive? Why?
  19. 19. COMPOSITION— What kind of substances the rocks are made of
  20. 20. Basaltic Igneous Rocks —made from lava/magma that is low in silica, rich in iron and magnesium. Rocks are dark-colored.
  21. 21. Granitic Igneous Rocks— made from magma/lava high in silica and oxygen. Rocks are light-colored.
  22. 22. Andesitic Igneous Rocks— have a composition between basaltic and granitic.
  23. 23. Diorite
  24. 24. Basalt
  25. 25. Granite
  26. 26. • Formed from sediments (rock fragments, mineral grains, animal & plant remains) that are pressed or cemented together or when sediments precipitate out of a solution.
  27. 27. • These sediments are moved by wind, water, ice or gravity. • Sedimentary rocks represent 7% of the Earth’s crust, but they cover 70% of the Earth’s surface. • Sedimentary rocks are fossil-carrying rocks.
  28. 28. What turns sediments into solid rock? • Water or wind breaks down and deposits sediment (erosion & deposition)
  29. 29. • The heavy sediments press down on the layers beneath (compaction)
  30. 30. • Dissolved minerals flow between the particles and cement them together (cementation)
  31. 31. How can sedimentary layers help us understand the age of fossils? • As sedimentary rocks are deposited, they form horizontal layers • Scientists know that the layers on top (and the fossils in the top layer) are YOUNGER than the fossils in lower layers.
  32. 32. 3 Types of Sedimentary Rocks: • Clastic (also called Detrial)—made of broken pieces of other rocks
  33. 33. Organic—remains of plants and animals are deposited in thick layers • Examples • Fossil rich limestone is made from the shells of ocean animals; used to make chalk 3 Types of Sedimentary Rocks:
  34. 34. • Chemical—minerals dissolved in lakes, seas, or underground water 3 Types of Sedimentary Rocks: Mineral crystals are made as the shallow water that has flooded the bottom of Death Valley evaporates. Click on image for full size (66K JPG) Courtesy of Martin Miller, University of Oregon
  35. 35. Examples • Limestone made when calcite mineral precipitates from sea water • Rock Salt— made from evaporation of sea waters
  36. 36. • Rocks that have changed due to intense temperature and pressure • “Meta” means “change” and morphosis means “form” in Greek • Igneous, sedimentary and other metamorphic rocks can change to become metamorphic rocks
  37. 37. What occurs in the Earth to change these rocks? • Pressure from overlying rock layers • High heat, but not enough to melt the rock • Rocks may be flattened or bent or atoms may be exchanged to form new minerals.
  38. 38. • *You can think of metamorphic rocks as a squished peanut butter & jelly sandwich in your lunch.
  39. 39. How are metamorphic rocks classified? • Foliated—mineral grains are flattened and line up in parallel bands • Example: gneiss formed from rearrangement of minerals in granite into bands
  40. 40. How are metamorphic rocks classified? • Non-Foliated—No bands are formed • Example: marble formed from limestone
  41. 41. Where do metamorphic rocks usually form? • Where magma intrudes relatively cool rock • Near colliding plates (near mountain ranges) • Places that are covered miles thick with other rock causing pressure • When hot water intrudes rock • Where a meteorite strikes Earth (rare) • Where lightning bolts strike rocks (rare)