Metamorphic rocks are formed when Igneous or Sedimentary rocks change due to heat or pressure, or both. This process is called metamorphism. The temperature of heat, compression and the presence of liquids contribute to metamorphism.
Contact metamorphism occurs in areas where rock layers come close or in contact with magma, which heats them intensely, causing them to change. The heat of the magma bakes the surrounding rocks causing them to change. An example of this type of metamorphism is marble. Marble is created from limestone by the process of contact metamorphism.
Regional metamorphism occurs in areas where plates collide. Compression causes the rock layers to be squeezed and they begin to heat and change due to pressure.
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