Volcanic activity can be intrusive and Extrusive:
- The high pressure inside the Earth keeps rocks in some parts of the Mantle semi-molten
- When this pressure is released the rocks become molten
- Due to the magma being less dense than the rock it rises
- Most magma doesnt reach the surface, but some can.
Intrusive volcanic activity:
- Takes place beneath the surface
- Large magma chambers; dykes, sills and batholiths
- When large chambers of magma cool beneath the surface they form domes of igneous rock called batholiths.
- When magma has flowed into gaps and it cools verticaly it forms dykes, if it cools horizontaly - sills
- Cracks may form as magama cools, this is…