Why does Sedimentary rock change to Metamorphic rock?
sedimentary rock changes into metamorphic rock only through the pressure exerted on it by the earths crust. It takes ALOT of pressure and even more time for thischange to take place. Different regions of the earths crust will exhibit unique types of meta/seda rock dependant on where this is taking place (e.g below/within mountains and volcanoes and under the oceans) igneous rocks are transformed under exactly the same conditions.