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Contents of 6.5 Why do metamorphic rocks exist at the surface?

6.5 Why do metamorphic rocks exist at the surface?

• Metamorphic rocks form very slowly
• Uplift and exposure is generally relatively rapid and rocks cool during uplift
• Loss of gas and fluids during metamorphic reactions
• Reactions cannot reverse if gas & fluids are gone
• High-grade metamorphic rock may rise to low-grade conditions and stay there for extended periods, re-metamorphosing them