The rock cycle
Part of Hall of Planet Earth.

The rock cycle takes eons. It strongly affects the carbon and other geochemical cycles by locking up critical elements for tens to hundreds of millions of years. Over the age of the Earth, some rocks have passed many times through the complete cycle. The igneous (granite), sedimentary (claystone), and meta-morphic (gneiss) rocks shown here represent stages in this cycle.
In This Section
Exhibit
Granite
This igneous rock formed when molten material intruded into the shallow crust, where it cooled and crystallized.
Exhibit
Claystone
Weathering and erosion of rocks like granites concentrate elements that are necessary to form clay minerals.
Exhibit
Gneiss
With burial and the increase in pressure, shales may be transformed by re-crystallization into metamorphic rock.