Layers of the Earth

Cards (13)

  • Layers of the Earth
    The Earth is made up of 3 main layers: Crust, Mantle, Core
  • The layers of the Earth
    Are different from one another
  • Crust
    • Thinnest layer of the Earth that ranges from only 2 miles in some areas of the ocean floor to 75 miles deep under mountains
    • Made up of large amounts of silicon and aluminum
    • Two types: oceanic crust and continental crust
    • Composed of plates on which the continents and oceans rest
  • Mantle
    • Solid but capable of flow (like hot asphalt or fudge)
    • Thickest layer of the Earth (making up 70% of the Earth's mass)
    • The hot material (magma) in the mantle rises to the top of the mantle, cools, then sinks, reheats, and rises again. These convection currents cause changes in the Earth's surface
  • Upper Mantle
    • Extends from the crust to a depth of about 410 kilometers (255 miles)
    • Mostly solid, but its more malleable regions contribute to tectonic activity
    • Includes the lithosphere and asthenosphere
  • Lithosphere
    • The solid, outer part of the Earth, extending to a depth of about 100 kilometers (62 miles)
    • Includes both the crust and the brittle upper portion of the mantle
    • The coolest and most rigid of Earth's layers
  • Asthenosphere
    • The denser, weaker layer beneath the lithospheric mantle
    • Lies between about 100 kilometers (62 miles) and 410 kilometers (255 miles) beneath Earth's surface
    • The temperature and pressure are so high that rocks soften and partly melt, becoming semi-molten
  • Transition Zone
    • From about 410 kilometers (255 miles) to 660 kilometers (410 miles) beneath Earth's surface
    • Rocks undergo radical transformations, becoming much, much more dense
  • Outer Core
    • Molten (liquid) metal that is about 4,700°C (8,500°F)
    • Located about 1,800 miles beneath the crust and is about 1,400 miles thick
    • Composed of the melted metals nickel and iron
  • Inner Core
    • Solid sphere composed mostly of iron
    • As hot as 6,650°C (12,000°F)
    • Heat in the core is probably generated by the radioactive decay of uranium and other elements
    • Solid because of the pressure from the outer core, mantle, and crust compressing it tremendously
  • Temperature increases as depth increases
  • The lithosphere (crust and upper mantle) is divided into separate plates which move very slowly in response to the "convecting" part of the mantle
  • The two images show that the layers of the Earth include the crust, mantle, and core, and that the lithosphere is divided into plates that move slowly