The process by which
rocks are created, changed, broken down
and transported to form new rocks. The cycle shows the three major groups
of rocks: igneous (cooled magma), sedimentary (made of particles of
other rocks or organisms) and metamorphic (deformed and altered igneous
or sedimentary rocks).
All three types of rocks can be broken down
into loose sediment by the effects of ice,
water, sun and wind. This sediment is eventually buried beneath
younger material to become compacted into sedimentary rock. If the
rock is buried to depths of 10km or greater it will be converted
to metamorphic rock by intense pressure and heat. Temperatures can
become so high at depth that rocks may melt to form magma.
Once magma has formed it tends to move towards areas of lower pressure
at shallower depths in the crust where it is cooler causing it to
solidify into igneous rock. The
rocks of the Manx
Group which make up most of the Isle of Man are transitional
between sedimentary and metamorphic rocks but they also contain
igneous rocks such as the granite
at Foxdale.