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Melting points vary with pressure. In nearly all substances the melting point increases with increasing pressure. The peridotite in the mantle is extremely hot and under immense pressure. When it is decompressed some melting occurs. The composition is not uniform and some minerals have lower melting points than others. The mafic minerals will be able to melt while the ultramafic mineralls generally will not.
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Why are basalts produced on divergent plate boundaries?
As the plates diverge, upper mantle rock rises and undergoes decompression melting along the rift. Because the upper mantle is comprised of mafic rock, the subsequent melt of this rock produces a mafic magma. Basalt and its coarse-grained intrusive twin, gabbro, are produced when this mafic magma solidifies.
Do adiabatic processes cause cooling by radiation or conduction or convection or insertion or decompression?
Decompression! Says my Physics Major Husband.(Are you in Mr. Fye's physical geography class, by any chance?)
What are hot spots cause by?
Mantle plumes
Why does decompression of the mantle cause production of mafic magma?
Decompression of the mantle produces magma, which is just molten rock. As the upper mantle (asthenosphere) moves closer to Earth's surface, it is under reduced pressure due to reduced depth. It does not get any warmer (in fact, it probably cools) but it melts.The only reason the rest of the mantle is not molten is the pressure on it; solid rock is more dense than liquid rock, so even when it's above its melting point, it can be pressurized into a solid. Drop the pressure, and it expands into a liquid.The same thing happens inside an auto radiator; pressure keeps the liquid coolant from expanding and turning into a gas (which does not absorb or transfer thermal energy from the engine well and will damage an engine). If you don't have a tight radiator cap or if you have a big leak in the system, your coolant easily boils.The opposite happens with water; it expands to form a solid unlike most other materials. If you put pressure on it, you can push it back into a liquid even when it's below 0 degrees C. This is why you slip on ice, ice skates work well, and old snow sleds have just two thin metal runners. High pressure melts the ice and you slide on a thin layer of water.Why is the magma mafic? It's due to content; being of low silica content it is low viscosity (runny) and will remain that way unless it passes through continental (felsic) lithosphere and picks up silica, thickening as it goes.
Does the weather cause a volcano to erupt?
No because weather has no affect on the earth mantle and the mantle is the source of magma for the volcano.
What is the gas that cause decompression?
helium
What cause inside the earth to melt?
Heat. Molten rock can be formed from the subduction and melting of cold, dense, wet oceanic crust at some convergent plate margins. The moisture in the rock assists in the melting of the crust and the rock surrounding it. Magma is also formed at hot spots in the mantle where hot material undergoes decompression melting as it rises. Decompression melting also occurs at the mid-ocean ridges where new oceanic crust is formed from rising mantle rock.
Why are basalts produced on divergent plate boundaries?
As the plates diverge, upper mantle rock rises and undergoes decompression melting along the rift. Because the upper mantle is comprised of mafic rock, the subsequent melt of this rock produces a mafic magma. Basalt and its coarse-grained intrusive twin, gabbro, are produced when this mafic magma solidifies.
What might cause solid rock in the Earth's interior to melt and begin to flow?
The mantle cause the mantle to flow.
Do adiabatic processes cause cooling by radiation or conduction or convection or insertion or decompression?
Decompression! Says my Physics Major Husband.(Are you in Mr. Fye's physical geography class, by any chance?)
What are hot spots cause by?
Mantle plumes
Why does decompression of the mantle cause production of mafic magma?
Decompression of the mantle produces magma, which is just molten rock. As the upper mantle (asthenosphere) moves closer to Earth's surface, it is under reduced pressure due to reduced depth. It does not get any warmer (in fact, it probably cools) but it melts.The only reason the rest of the mantle is not molten is the pressure on it; solid rock is more dense than liquid rock, so even when it's above its melting point, it can be pressurized into a solid. Drop the pressure, and it expands into a liquid.The same thing happens inside an auto radiator; pressure keeps the liquid coolant from expanding and turning into a gas (which does not absorb or transfer thermal energy from the engine well and will damage an engine). If you don't have a tight radiator cap or if you have a big leak in the system, your coolant easily boils.The opposite happens with water; it expands to form a solid unlike most other materials. If you put pressure on it, you can push it back into a liquid even when it's below 0 degrees C. This is why you slip on ice, ice skates work well, and old snow sleds have just two thin metal runners. High pressure melts the ice and you slide on a thin layer of water.Why is the magma mafic? It's due to content; being of low silica content it is low viscosity (runny) and will remain that way unless it passes through continental (felsic) lithosphere and picks up silica, thickening as it goes.
If a small hole is made in a plane at altitude can it cause explosive decompression and tear the plane apart?
It will cause an explosive decompression but hopefully not tear it apart because planes are assembled in small panels so if one takes a hole it should not spreadhttp://site1.wikianswers.com/images/blank.gif?v=22222
What is the evidence that the Earth's mantle contains magma?
The eruption of volcanoes. If the lava flow is still underground and not exposed to air, its called Magma. Once it reaches the surface and encounters air, its called lava. Essentially, Magma and Lava are the same, there's no chemical difference other than its interaction to air.
What is a destructive force caused by the convection in the mantle?
Convection currents in the Earth's mantle are thought to be responsible for plate motions and therefore can ultimately be considered the cause of earthquakes. Mantle upwelling or mantle plumes are also thought to be the cause of hotpots which cause intra-plate volcanic activity such as that which occurs in Hawaii.
Does the weather cause a volcano to erupt?
No because weather has no affect on the earth mantle and the mantle is the source of magma for the volcano.
What part of the earths mantle that flows and moves the plates of the earth?
Mantle plumes are in the mantle, BELOW the Earth's crust. The circulation of heat from the lower mantle to the upper mantle can cause "hot spots" in the overlying crust, heating the magma in the areas.
