Rocks make up the Earth’s surface and there are three main types including igneous, sedimentary, and metamorphic. These three types of rocks generally move through a cycle, known as the Rock Cycle (shown below). Hot molten rock under the Earth’s surface creates igneous rocks, which can either cool underground or aboveground. These igneous rocks can then be exposed to the surface elements by tectonic processes, and be exposed to the atmosphere causing breakdown. The breakdown of rocks creates sediment, which eventually gets moved, deposited, and can be buried to form sedimentary rocks. Then, these sedimentary rocks can become further buried and succumb to high heat and pressure causing mineral changes in the rock. These mineral changes causes the formation of metamorphic rocks. If buried deep enough, rocks again melt into magma and become igneous rocks once more. Rocks are a great indication of the Earth’s geologic past, and can be used as a guide to interpret and understand current environments.
The rock cycle