Definition Metamorphic rocks: rocks that have been modified by heat, pressure and chemical process . Usually deep within the earth
Slate vs. shale Slate and shale look similar, yet are different.
Specific changes Large areas of rock are under intense heat and pressure. Rocks are already under high temperature. Friction of moving layers adds heat.
Foliation When shale undergoes intense pressure, the minerals are formed into parallel layers. This process is called foliation. Shale -> slate -> phyllite -> schist
Contact metamorphism Hot magma forces its way into overlying rock. Hot liquids and gases from magma also enter rock and react with its minerals.
Rock cycle 1. igneous rocks are formed from magma 2. Igneous rocks erode (wear out) by weathering, forming sediments. 3. Sediments form sedimentary rocks. 4. If sedimentary rocks are buried deep and are involved in movements of earth’s crust, they become metamorphic rocks. 5. If rocks are forced deep enough, they reach such high temperatures that they become magma.