Earth crust


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Earth crust

  1. 1. Erath Crust Vivek Srivastava
  2. 2. Earth Layers • The Earth is divided into four main layers. *Inner Core *Outer Core *Mantle *Crust
  3. 3. The Earth’s Crust • The crust is the thinnest layer on Earth, 5 km to 100 km • There are two types of crust • Oceanic crust – made mostly of the igneous rock basalt. Found under the ocean. Relatively thin, 5 km to 7 km. Contains more iron than the Continental crust, therefore is more dense. • Continental crust – made mostly of granite. Found under the continents. Relatively thick, up to 100 km.
  4. 4. Special parts of the Crust • Lithosphere • Crust is the upper part of the lithosphere. • Broken up into large plates. • The uppermost part of the mantle is also part of the Lithosphere • Asthenosphere • Upper part of mantle, below lithosphere • 130 – 160 km thick • Cooler part of the mantle that the lithosphere plates slide on top of.
  5. 5. The Earth’s Mantle • Located directly above the outer core • Starts below the crust • Is the largest layer • 80% of the Earth’s volume & 68% of Earth’s mass
  6. 6. The Earth’s Mantle • Composed of more iron than the crust. • Density, pressure, and temperature all increase the deeper you go in the mantle • Temperature ranges from 870 C – 2200 C
  7. 7. Special layers of the mantle • Lithosphere – crust plus the upper, solid part of the mantle. Forms plates. • Asthenosphere – just under the lithosphere. Slow moving “Silly putty” layer on which the lithospheric plates slide. (Solid rock that flows very slowly.)
  8. 8. The Earth’s Core The Earth’s Core • Composed of the inner and outer core • Both are made of iron and nickel
  9. 9. The Earth’s Outer Core The Outer Core - Liquid • Surrounds the inner core • Temperature ranges from 2200 C – 5000 C near inner core • Molten (liquid) iron and nickel
  10. 10. The Earth’s Inner Core The Inner Core - Solid • Temperature reaches 5000 C • Solid iron and nickel • Usually both would be liquid but are solid in the core because of the incredible pressure • The solid core is the source of Earth’s magnetic field
  11. 11. Magnetosphere • The inner core and outer cores do not turn at the same speed as the rest of the earth. • Causes a generator effect which produces a magnetic field. • It protects us from some of the sun’s harmful radiation.
  12. 12. • What does the inside of the Earth look like? • How do scientists know that there is a solid inner core?
  13. 13. Determining the composition of the Earth • Scientists cannot see the interior of the planet, or drill to the core, so they use seismic waves to determine the composition of the layers. • Seismic waves: are vibrations that are produced when an earthquake happens. • Seismic waves travel at different speed depending on the composition and density of material. Measuring these waves tells us what is in the Earth’s layers, and how the materials change.
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  15. 15. What do you know about these layers?