In northern Anatolia a zone of pre-Liassic orogenic deformation is located mainly between the internal Anatolian massifs and the North Anatolian fault. This belt consists of metamorphic rocks in blueschist, greenschist, and amphibolite facies and an ophiolitic, dynamometa-morphic melange. The metamorphic rocks represent deformed and metamorphosed oceanic crust and upper mantle, whereas the melange rocks originated in diverse environments in abyssal plain, trench, arc-trench–gap, and forearc environments. The evolution of these assemblages is interpreted as a product of subduction, probably associated with the closure of the Tethys. Subduction-related deformation and meta-morphism terminated diachronously from pre–Late Triassic in the west to pre–late Liassic in the east, probably as a result of the diachronous closure of the Tethys.