Question: what four characteristics determine the type of metamorphic rock?
Answer: Chemical Composition of the Protolith. The type of rock undergoes metamorphism is a major factor in determing what type of metamorphic rock it becomes. ... 
Temperature. ... 
Pressure. ... 
Fluids. ... 
Time. ... 
Regional Metamorphism. ... 
Contact Metamorphism. ... 
Hydrothermal Metamorphism.