What determines the difference between a slate and a gneiss rock that both are formed from a shale? What role does the parent rock play in determining the type of metamorphic rock that will be formed? In a rock that had undergone contact metamorphism, would you expect to find foliation? Why or why not?
Metamorphic rocks were once sedimentary, igneous or even other metamorphic rocks that have been changed by heat and pressure. so i think this will help you.
