EARTH.SCI

• There is more to Earth than what meets the eye
• Our knowledge of what's inside the earth has been limited due to the fact that no one can travel inside it and tell the tale of what they found
• Layers of the Earth based on rheology

  • Lithosphere
  • Asthenosphere
  • Mesosphere
  • Outer core
  • Inner core
• Layers of the Earth based on chemical variations

  • Crust
  • Mantle
  • Outer core
  • Inner core
• Lithosphere


  The crust and the upper layer of the mantle, a rigid layer that can break under stress
• Types of crust


  • Continental crust
  • Oceanic crust
• Continental crust


  Crust that makes up the continents, about 40-70 km thick, made up of less dense granitic rocks
• Oceanic crust


  Crust that underlies the ocean floor, average thickness of 5 km, made up of more dense basaltic rocks
• The crust is largely composed of alumina (A1203) and silica (SiO2)
• The mantle is the layer of the earth that lies below the crust and is by far the largest layer making up 84% of Earth's volume
• Mantle


  A semi-solid rocky and very hot layer that acts similar to plastic
• The mantle extends down to 2,890 km into the Earth's surface
• Temperatures in the mantle range from 500 to 900 degrees Celsius in the upper portion to over 4,000 degrees Celsius near the core boundary
• Earth's mantle


  Believed to be composed of ferro-magnesium silicate rocks
• Core layers


  • Outer core
  • Inner core
• Outer core


  Located below the mantle, the only layer that is liquid, made up of molten nickel and iron, about 2,270 km thick
• Temperature in the outer core ranges from 3,700 degrees C to 4,300 degrees C
• Inner core


  The solid center of the earth, with a diameter of about 1,220 km, mostly composed of solid iron
• The inner core is extremely hot, with its recently determined temperature of about 6000 degrees Celsius
• The inner core gives the planet its magnetic features
• Asthenosphere


  About 180 km thick, where magma lies, can deform and reshape under heat
• Heat energy from the magma circulates in what we call convection currents
• Movements in the asthenosphere

  Can lead to the formation of mountains, volcanoes, islands, trenches, and mid-ocean ridges
• Why is it that the composition of the outer core is liquid?

  the outer core remains liquid as there is not enough pressure to keep it in a solid state