Rocks

The rock cycle is a depiction of how the three main rock types can change from one type to another. As rocks exposed at the surface weather, they form sediments that can be deposited to form sedimentary rocks. As sedimentary rocks are buried beneath more sediment, they are subjected to increases in both pressure and temperature, which can result in metamorphism and the formation of metamorphic rock. If the temperature of metamorphism is extremely high, the rock might melt completely and later recrystallize as an igneous rock. Igneous, sedimentary, and metamorphic rocks can erode and later form sedimentary rock. Rocks can move through the rock cycle along other paths, but uplift or burial, weathering, and changes in temperature and pressure are the primary causes of changes in rocks from one type to another.