What Energy Converted Sedimentary Rocks Into Metamorphic Rocks?

What Energy Converted Sedimentary Rocks Into Metamorphic Rocks? What energy converted sedimentary rocks into metamorphic rocks? Metamorphic rocks started out as some other type of rock, but have been substantially changed from their original igneous, sedimentary, or earlier metamorphic form. Metamorphic rocks form when rocks are subjected to high heat, high pressure, hot mineral-rich fluids