Which type of metamorphism is driven by proximity to magma and elevated temperatures?

• A. Contact metamorphism
• B. Regional metamorphism
• C. Dynamic metamorphism
• D. Burial metamorphism

Answer: (A)

Proximity to magma and elevated temperatures drive contact metamorphism. When magma intrudes into surrounding rock, the intense heat rises the temperature of nearby rocks, causing recrystallization and new mineral textures in a relatively small, localized zone around the intrusion called the contact aureole. Because heat from the magma is the dominant factor, the metamorphism produced is often nonfoliated and focused near the intrusion. As you move farther from the magma, temperatures drop and the metamorphic effects lessen. Other forms of metamorphism arise from different conditions: regional metamorphism from high pressures and temperatures over large areas during tectonic events, burial metamorphism from deep burial increasing pressure and temperature, and dynamic metamorphism from intense deformation and shear.