Metamorphic Processes

Metamorphic rocks are generated by recrystallization of either igneous or sedimentary rocks by the action of any or all of the following:

• Pressure

• Temperature

• Pore Fluids

The lower limit of metamorphic temperatures is 150 degrees Celsius. The upper limit is the melting temperature when magma forms.

The type of metamorphic rock is determined by the parent rock and the P/T conditions. In general, metamophism causes:

• Growth of new minerals
• Deformation and rotation of mineral grains
• Recrystallization of minerals as larger grains
• Production of strong brittle rocks or anisotropic rocks weak in shear.