The diagram illustrates the rock cycle, showing how three main types of rock – igneous, sedimentary and metamorphic – are continuously formed, transformed and destroyed through a series of natural processes.
Overall, the cycle is circular in nature, beginning with molten magma and involving cooling, erosion, burial, heat, pressure and melting, which together allow rocks to change from one form to another over time.
Initially, magma rises from beneath the Earth’s surface. When it cools quickly, either underground or after volcanic eruption, it solidifies to form igneous rock. Over time, igneous rock is exposed at the surface and gradually broken down by weathering and erosion into smaller particles such as sand and stones. These sediments are then transported and deposited, eventually compacting to become sedimentary rock.
As sedimentary rock is buried deeper within the Earth, it experiences increasing heat and pressure. This causes it to change into metamorphic rock. If temperatures continue to rise, metamorphic rock can melt and turn back into magma, completing the cycle. Additionally, both sedimentary and metamorphic rocks may be uplifted to the surface, where they are again subject to erosion, allowing the process to repeat.