Where Does the Rock Cycle Start?

Mountains are an impressive part of the rock cycle.

Rocks are never created or destroyed. Over millennia, they are broken up, molten down and reformed into new rock types in a process called the rock cycle, which begins in the fiery recesses of the Earth's core.

Rock Types

The three types of rocks on the Earth's surface include igneous rocks, which are made from magma; metamorphic rocks, which have been changed from their original state by geological forces; and sedimentary rocks, which are layers of sediment that have been pressed together into solid rock form.

Rock Cycle Beginning

The U.S. Geological Survey notes that technically, the rock cycle has no beginning or end. However, for the sake of convenience and clarity, and because every rock on Earth can be traced back to a molten state, the cycle is often said to begin with magma, or molten rock beneath the Earth's surface.

Magma Function

As magma cools, it forms an igneous rock layer that is pushed up into mountains by shifting tectonic plates, volcanic activity and other forces.

Rock Cycle Process

Mountains break apart over time, eventually wearing down into soil, clay and sand. These sediments build up into layers, forming new rocks. Heat and pressure changes these sedimentary rocks into metamorphic rocks, which are eventually melted back down into magma.

References

• U.S. Golological Survey: Geology 1: Rock Cycle Lab Introduction
• Sci Links: The Rock Cycle