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| the comparatively thin outer skin that ranges from 3 km (2 miles) at the oceanic ridges to 70 km (40 miles in some mountain belts) |
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| a solid rocky (silica-rich) shell that extends to a depth of about 2900 km (1800 miles). 82% of Earth's volume. Upper portion is ultramafic rock peridotite. Has PLASTIC behavior because it is solid, but flows and can transmit s-waves. |
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| Boundary between the two dissimilar materials. |
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| Earth's outermost layer consisting of crust and uppermost mantle. Forms a relatively COOL, rigid shell. |
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| Layer beneath lithosphere located in upper mantle. It is a soft, WEAK layer. Temperature and pressure of the layer results in small amount of melting |
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| Layer below asthenosphere. Rocks are very HOT and capable of very gradual flow. |
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| Liquid layer beneath mesosphere. Composed mostly of an iron-nickel alloy. Has a convective flow within which generates Earth’s MAGNETIC field. |
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an iron-rich sphere with a radius of 3486 km (2161 miles).
Stronger than the outer core. Despite extremely high temperatures, it behaves like a SOLID due to immense amount of pressure. Proven to be solid because p-waves that past through show increased velocity. Predicted by Inge Lehmann in 1936. Has an average density of 11 g/cm3. Rotates faster than the earth's surface |
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| Mohorovicic discontinuity (the Moho) |
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| Boundary separating crust, which has different a composition, from the underlying mantle. Mantle transmits waves FASTER and is therefore identified by a change in the velocity of P-waves. |
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Discovered in 1914 by Beno Gutenberg.
Based on the observation that P waves die out at 105 degrees from the earthquake and reappear at about 140 degrees. 35 degree wide belt is named the P-wave shadow zone |
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| The 35 degree belt around the world where p-waves diminish and eventually die out completely about 105 degree from an earthquake. Produced by bending (refracting) the p-waves which enter the core. |
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| The transfer of heat by mass movement or circulation in substance. Reason why mantle is capable of flow since it has to transmit and distribute heat from core. |
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Density about 3.0 g/cm3
Composed mainly of the igneous rock basalt |
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Average rock density about 2.7 g/cm3
Composition comparable to the felsic igneous rock granodiorite |
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Larger than mars. Has inner and out sphere. Average rock density about 2.7 g/cm3 made of material that conducts electricity and it is mobile
Composition comparable to the felsic igneous rock granodiorite |
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Temperature increasing with depth. Varies considerably from place to place
Averages between about 20C and 30C per km in the crust (rate of increase is much less in the mantle and core) |
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| Radioactive decay of isotopes, heat released from iron crystallization to form outer core, colliding particles during Earth formation |
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| 3 Major processes that have contributed to Earth’s internal heat |
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| Heat flow in the crust that act to equalize temperature differences. Ex: metal spoon left on hot pan. High in mid-ocean ridges and low in ancient shields. |
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| Transfer of heat by the mass movement or circulation of a substance. Likely explanation for mantle's heat transfer since rocks are relatively poor conductors. |
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| Earth's most abundant mineral found in lower mantle. Compressed version of spinel |
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| Lowest layer of the mantle. P-waves undergo sharp decrease in speed b/c it is partial molten |
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| Propels lithospheric plates, generates mountain belts, causes worldwide earthquakes and volcanoes. |
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| 3 actions of mantle convection |
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