Final answer:
Metamorphic rocks are formed through the application of high heat and pressure, causing transformations in the protolith into a new rock with different physical and chemical properties.
Step-by-step explanation:
Metamorphic rocks require large amounts of heat and pressure to form. These conditions can occur in various geological settings, such as near magma chambers or during the processes of mountain building.
The application of heat and pressure for extended periods of time causes the transformation of the protolith, or parent rock, into a new metamorphic rock through processes such as recrystallization and the introduction of new minerals.
For example, under metamorphic conditions, sandstone can transform into quartzite, shale into slate, and limestone into marble. The specific type of metamorphic rock that forms depends on factors such as the composition of the original rock, the degree of heat and pressure applied, and the duration of the metamorphic conditions.