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Earth’s Interior and Plate Tectonics. CHAPTER 4. Earth’s Composition:. Not just solid rock Distinct layers Each layer has certain physical properties. 3 Main Layers. Crust Mantle Core. Crust. Outermost layer 5 – 100 km thick Thinnest layer 2 types of crust < 1% of Earth’s mass.
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Earth’s Interior and Plate Tectonics CHAPTER 4
Earth’s Composition: • Not just solid rock • Distinct layers • Each layer has certain physical properties
3 Main Layers • Crust • Mantle • Core
Crust • Outermost layer • 5 – 100 km thick • Thinnest layer • 2 types of crust • < 1% of Earth’s mass
Continental Crust • Average thickness of 30 km • Composition similar to granite
Oceanic Crust • Average thickness from 5-8 km • Composition similar to basalt
Mantle • Between crust and core • Extremely thick and 67% of Earth’s mass • Large amounts of Iron and Magnesium
The Core • 33% of Earth’s mass • 2 separate layers
Outer Core • Liquid layer
Inner Core • Solid and dense • About 6,378 km below the surface • 6,000 oCelcius (hotter than Sun’s surface)
Lithosphere • Made of the Crust and Upper Mantle • Rigid • About 150 km thick
Asthenosphere • Part of the mantle • Made of rock (molten) • Flows like putty (very viscous)
Tectonic Plates • Rigid, solid rock • Move around on Asthenosphere • Jigsaw puzzle
Deepest hole drilled: • 12.2 km into the earth • Kola Pennisula, Russia 1984
Seismic Waves • From earthquakes • Travel through earth layers • Speed depends on density of material