EARTH SCIENCE
TECTONICS
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
It becomes less dense and rises.
|
|
|
It becomes more dense and rises.
|
|
|
It becomes more dense and sinks.
|
|
|
It becomes less dense and sinks.
|
Detailed explanation-1: -The magma that is produced by partial melting is less dense than the surrounding rock. Magma from partial melting of mantle rocks rises upward through the mantle, and may pool at the base of the crust, or rise through the crust.
Detailed explanation-2: -The mantle is made of molten rock heated to very high temperatures. This semisolid magma continues to move upwards through the crust, experiences less pressure and so becomes more fluid. The result is the lava we see erupting from active volcanoes.
Detailed explanation-3: -If they are less dense than the liquid they will float. If liquid is squeezed out by pressure, then crystals will be left behind. Removal of crystals can thus change the composition of the liquid portion of the magma.
Detailed explanation-4: -Because the magma is less dense than the surrounding mantle material it will rise. Pressure in the magma cracks the overlying rocks. Then the magma injects into the crack. This process repeats thousands of times, bring the magma towards the surface.
Detailed explanation-5: -Molten rock, i.e., magma, is less dense and more buoyant than the surrounding rock, as a result magma rises through Earth’s crust. Most magma is trapped in the crust, but some erupts onto the Earth’s surface as lava.