Geological cycle

The geological cycle is the continuous, slow, cyclic process by which the rocks of the earth's crust are formed, destroyed and re-formed into other kinds of rock. It has no start or end. It links the rock cycle, the hydrological cycle and plate tectonics.

 Magma --cooling--> Igneous rock
   ^                    |
 melting         weathering, erosion
   |                    v
 Metamorphic <--heat,-- Sediments
 rock         pressure     |
   ^                       |compaction,
   |                       v cementation
   +------heat,--------Sedimentary rock
        pressure

• Magma cools to igneous rock.
• Weathering, erosion, transport and deposition give sediments, which become sedimentary rock by lithification.
• Heat and pressure change any rock into metamorphic rock.
• Deep burial and melting return the rock to magma.

Uplift brings deep rocks back to the surface. Engineers use this idea to understand why different rock types occur at a site.