Formation of metamorphic rocks
is different from from the other rock types.
form from sediments and igneous
form from lava or magma -
metamorphic rocks form from igneous, sedimentary, or other metamorphic
As the word "metamorphism" says, it is a change from
one rock to another, without the first rock turning into magma or
sediments in between.
There is no melting, it is a
As igneous, sedimentary, or metamorphic rock is pushed
deeper and deeper down to the interior of the Earth, temperatures and
pressures increase. The rock is also experiencing
stress which makes it foliated.
These new conditions make the
minerals in the rock unstable. When a mineral gets unstable, chemical
reactions will happen, where a mineral turns into another, more stable
mineral in the new conditions.
As the conditions change, gradually the
minerals in the rock change, which turns the rock into a new rock.
temperatures rise to a point where the rock melts and turns into magma,
igneous rock is formed.
As long as the rock stays
metamorphic process and metamorphic rock is formed.