Igneous and sedimentary rocks are converted to metamorphic rocks when subjected to pressures and temperatures of a magnitude sufficient to transform the existing rock types to other rock types, but less than the pressures and temperatures required to melt rock.
(Igneous and sedimentary rocks; are converted; to metamorphic rocks; T:when subjected to pressures and temperatures of a magnitude sufficient to transform the existing rock types to other rock types, but less than the pressures and temperatures) (a magnitude sufficient; to transform; the existing rock types; to other rock types) (the pressures and temperatures; required; to melt rock)
Igneous and sedimentary rocks a magnitude sufficient the pressures and temperatures
are converted to transform required
to metamorphic rocks T:when subjected to pressures and temperatures of a magnitude sufficient to transform the existing rock types to other rock types, but less than the pressures and temperatures
the existing rock types to other rock types
to melt rock