A metamorphic rock is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes. Examples of these rock types include marble, slate, gneiss, schist.
A metamorphic rock is a type of rock which has been changed by extreme heat and pressure. Its name is from 'morph' (meaning form), and 'meta' (meaning change). The original rock gets heated (temperatures greater than 150 to 200 °C) and pressured (1500 bars). This causes profound physical and/or chemical change.
Contact Metamorphism. CONTACT METAMORPHISM OCCURS WHEN HOT MAGMA FORCES ITS WAY UP INTO THE CRUST. WHEN THIS HAPPENS THE HEAT COOKS THE ROCKS NEARBY CAUSING METAMORPHISM. Eventually the magma will cool and become a layer of igneous rock that cuts into the rocks around it.
TEXTURES Textures of metamorphic rocks fall into two broad groups, FOLIATED and NON-FOLIATED. Foliation is produced in a rock by the parallel alignment of platy minerals (e.g., muscovite, biotite, chlorite), needle-like minerals (e.g., hornblende), or tabular minerals (e.g., feldspars).