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Layers of the Earth

Layers of the Earth

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Layers of the Earth

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  1. Layers of the Earth Crust Mantle Outer Core Inner Core

  2. Crust • Avg. thickness- 35 km • 2 kinds • 1. Continental • 20-90 km thick; known as sial; contains older rock, primarily granite; less dense than oceanic crust • 2. Oceanic • 5-10 km thick; known as sima; younger rock, primarily basalt; more dense crust

  3. Crust Cont. • All life exists in the crust of the Earth. • Approximately 90 different elements are found in the crust, but 5 make up 90% of the crust- oxygen, silicon, aluminum, iron, & calcium • Sodium, potassium, & magnesium are the most common elements in the remaining 10%

  4. Mantle Earth’s mantle contains 80% of Earth’s volume & 67% of Earth’s mass. Common elements found in the mantle are: silicon, oxygen, aluminum, iron, & magnesium. The mantle consists of solid rock, except for the asthenosphere. Density increases in the mantle as depth increases

  5. Layers of the Mantle • The mantle is divided into 3 sections. • Lithosphere- consists of the uppermost part of the mantle (rigid rock) & the crust. Average thickness is 100 km. • - Moho’s discontinuity- boundary separating crust from mantle; discovered in 1909 using seismic data; found approximately 30 km from Earth’s surface

  6. Layers of the Mantle cont. 2. Asthenosphere- 100-250 km deep; more fluid layer, but not liquid 3. Mesosphere- lowest layer; rigid rock; 660-2900 km deep -temperature increases with depth, as does density

  7. Core Diameter of the total core is 6960 km = to approximately the diameter of Mars The core is 1/6 of Earth’s volume & 1/3 of its total mass

  8. Outer Core • Approximately 2270 km thick • Temperature approximately 4000-5000º Celsius • Liquid; very dense molten iron & nickel • Believed to create Earth’s magnetic field; similar to the magnetic field around a magnet

  9. Inner Core • Temperature is about 5000º Celsius • Believed to be solid; very dense iron & nickel • Remains solid due to immense pressure (may be 2 million times stronger than normal pressure exerted on Earth’s surface); molecules can not spread out & become liquid