The Armutlu peninsula is a composite tectonic entity made up of sections of the Sakarya continent, the Rhodope-Pontide fragment and an ophiolite. These were assembled following a continental collision between Gondwanaland and Laurasia during the Late Cretaceous. The northern margin of the Sakarya continent underwent progressively increasing deformation prior to and during the advancing collision, due to continued convergence between the two continents. Initially, the leading edge of the continent subsided under the load of an approaching ophiolitic slab. Following this, a north-directed thrusting and folding occurred during the Turonian.