Metamorphic Rocks

Have you ever watched something begin to change shape as it was heated? What happened to the object just before it reached its melting point? Metamorphic rocks are rocks that have reached this point of deformation. It is very difficult, however, to directly observe the formation of metamorphic rocks because they form very deep within the Earth's crust over very long periods of time. They must form at great depth because this is where temperature and pressure are the most intense. In this topic, you will learn about metamorphic rocks, how they form, and how they are classified.

Essential Questions

• How do metamorphic rocks form?
• What are the physical and chemical characteristics that distinguish metamorphic rocks from the other two rock types?