Metamorphism in which a rock that has been metamorphosed to a fairly high grade is later remetamorphosed at lower temperature and pressure to a lower grade.

Mineral changes within a rock that are caused by adjustments to conditions of reduced temperature and pressure.

metamorphism that results in a high-grade mineral or assemblage changing to a lower grade mineral or assemblage. Retrograde metamorphism usually results from the infiltration of water at lower temperatures than the maximum metamorphic temperature attained.