Sedimentary, Igneous and Metamorphic Rocks

• What are the three main types of rocks?

  Sedimentary rocks, igneous rocks, and metamorphic rocks
• How are sedimentary rocks formed?

  • Formed from sediments (small grains or particles)
  • Sediments settle in lakes and rivers
  • Layers build up through stratification
  • Lower layers are compacted by the weight of higher layers
  • Cementation may occur when minerals dissolve and create natural cement
• What is stratification in the context of sedimentary rocks?

  Stratification is the process where layers of sediments build up
• What happens during compaction of sedimentary rocks?

  Lower layers are squeezed from the weight of higher layers
• What is cementation in sedimentary rock formation?

  Cementation is when some minerals in the sediments dissolve and create a natural cement
• Name three examples of sedimentary rocks.

  Shale, sandstone, and limestone
• How are igneous rocks formed?

  • Formed by the cooling of magma or lava
  • Magma is hot liquid rock underground
  • When magma reaches the surface, it is called lava
• What are the two categories of igneous rocks?

  Intrusive and extrusive igneous rocks
• How do intrusive igneous rocks form?

  Intrusive igneous rocks form underground from cooled magma
• How do extrusive igneous rocks form?

  Extrusive igneous rocks form above ground from cooled lava
• Give three examples of igneous rocks.

  Granite, obsidian, and pumice
• How do metamorphic rocks form?

  • Form from sedimentary or igneous rocks
  • Occur under extremely high temperature and pressure
  • Change into a completely different rock
• What does the sedimentary rock shale become under extreme temperature and pressure?

  Slate
• What does the sedimentary rock limestone become under extreme temperature and pressure?

  Marble
• What are the key differences between sedimentary, igneous, and metamorphic rocks?

  • Sedimentary: Formed from sediments, involves stratification, compaction, and cementation
  • Igneous: Formed from cooling magma or lava, categorized as intrusive or extrusive
  • Metamorphic: Formed from existing rocks under high temperature and pressure, changes structure
• What should you do next time you find a rock?

  See if you can identify if it is a sedimentary, igneous, or metamorphic rock