Describe igneous activity at convergent plate boundaries. What ...

[jwb375]

Describe igneous activity at convergent plate boundaries. What will be an ideal response?

Question 2

Briefly explain how magma can originate at spreading zones if temperatures at such shallow depths
  cannot alone produce melting What will be an ideal response?

[jharrington11]

Answer to Question 1

The volcanoes tend to be composite volcanoes with lava flows and pyroclastic eruptions of
intermediate to felsic composition. Viscous lavas may erupt as lava domes in very explosive eruptions.

Answer to Question 2

The material is kept from melting because the lithostatic pressure of the overlying rock raises its
melting temperature. The divergence of the plates and the fracturing that accompanies it reduce the
pressure and lower the material's melting temperature, which allows the rock to melt and become
magma.