Metamorphic rocks: have been changed minerlogically and/or texturally through heat, pressure, or fluids. Change without dissolving completely or melting completely. They are a solid the entire time. But are dramatically changed my heat, pressure or fluid moving through rocks. Metamorphic rock provides a window into the past. You can find out what type of rock there is by what rocks are left over. You can see the past by working backwards. Metamorphism occurs at higher temperatures and found below the earth surface. As you get closer to the mantle, you get warmer and warmer. When you touch the wall deep down, the walls are really warm. The temperature goes up as you go down on the earth. Blue schist has hi pressure but low temperature ( low grade); surface rock (crust) was brought down fast. It went down fast but didn"t have time to heat up, (found in subduction zones.