MEPX
Chapter 3 of 10All chapters
  1. 1Inside the Earth
  2. 2Plate tectonics
  3. 3Rocks and minerals
  4. 4Shaping the surface
  5. 5Water on Earth
  6. 6Earthquakes
  7. 7Volcanoes
  8. 8The atmosphere
  9. 9Geological time
  10. 10Resources and hazards

Chapter 3 of 10

Rocks and minerals

Three types, one cycle.

The three

Igneous rock cools from molten material. Sedimentary rock forms from compressed layers of particles. Metamorphic rock is either type altered by heat and pressure without melting.

  • Fossils appear almost only in sedimentary rock.
  • Granite is igneous, sandstone sedimentary, marble metamorphic.

The rock cycle

Each type converts into the others over geological time through melting, erosion, burial and uplift. Nothing is permanent, only slow.