 The late Archean Eon to Early Proterozoic Eon corresponds to a period of increasing crustal recycling, suggesting subduction.Evidence for this increased subduction activity comes from the abundance of old granites originating mostly after 2.6 Ga.The occurrence of eclogite, (a type of metamorphic rock created by high pressure, > 1 GPa), is explained using a model that incorporates subduction.