Review questions on magma formation

Which of the following acts to keep a rock solid (instead of melting)?
1. an increase in temperature
2. an increase in the vibration within a lattice
3. an increase in confining pressure
4. all of the above
5. none of the above
With increasing pressure (depth), the melting point of rocks and minerals generally _____
1. decreases
2. increases
3. does not change
4. becomes dependent on rock type
5. there is no definite relationship between melting point of a solid and change in pressure
Which of the following happens along oceanic divergent boundaries?
1. oceanic crust moves toward the ridge in a conveyor-belt manner
2. most of the mantle is molten, not solid
3. solid asthenosphere rises as plates move apart
4. magma generated in the crust drips down into the mantle
5. all of the above happens along divergent boundaries
Along divergent plate boundaries, magma formation takes place typically due to:
1. melting of the plates as they move apart as a result of frictional heating
2. increased pressure from plate movement
3. pressure being reduced (decompression melting) as the plates move apart
4. water being released under pressure which lowers the melting temperature of the overlying asthenosphere
5. hot spots, which always occur along divergent boundaries
In subduction zones, magma formation takes place typically due to:
1. melting of the subducting plate as a result of frictional heating
2. increased pressure from plates colliding
3. pressure being reduced (decompression melting)
4. water being released under pressure which lowers the melting temperature of the overlying asthenosphere
5. hot spots, which always occur along subduction zones
How does the addition of water cause melting?
1. it heats the rocks
2. it decreases the pressure on the rocks
3. it increases the temperature while decreasing the pressure
4. it changes the location of the liquid-solid boundary
5. None of the above
The main way water mainly gets into a subduction zone is by:
1. heating of the overlying continental crust
2. a decrease in pressure that causes melting
3. rain associated with eruptions in the island arc
4. seawater introduced into oceanic crust at the mid-ocean ridge, prior to subduction
5. all of the above
What generally happens when magma from subduction zone passes through thick continental crust?
1. most magma reaches the surface with minor modification
2. the magma solidifies in sheeted dikes with a composition of basalt
3. the magma interacts with the crust, forming felsic or intermediate compositions
4. the oceanic crust melts
5. all of the above happens

Review questions on magma formation

Quiz