Ophiolite emplacement and the evolution of the Taurus suture zone, southeastern Turkey

Abstract

The interior of the southeastern Taurus Mountains of Turkey is occupied by an extensive area of metamorphic rocks known as the Bitlis Massif, previously regarded as pre-Permian in age. An ophiolitic melange occurs within the Bitlis Massif, and detailed mapping has shown that the melange can be subdivided and an internal structure recognized. It contains components of Late Cretaceous age, some of which have been metamorphosed, indicating an Alpine metamorphic event. It is proposed that the Bitlis Massif is a composite structural entity consisting of a northern area of pre-Permian metamorphic rocks and a southern zone of Alpine rocks that have undergone high-pressure—low-temperature meta-morphism. The Bitlis Massif is thrust southward over an ophiolite-flysch complex, which is also thrust southward over sedimentary rocks of the Arabian foreland. The ophiolite-flysch complex is here divided into three zones, one of which is an ophiolitic-wildflysch zone correlated with ophiolitic gravity slides occurring further west in the southeastern Taurus Mountains. In the tentative plate-tectonic model for the evolution of a section of the southeastern Taurus Mountains presented here, two episodes of ophiolite emplacement are recognized. It is suggested that the ophiolitic-wildflysch represents trench melanges that were not subducted but were thrust out of the trench zone because of uplift associated with the final phase (Late Cretaceous) of subduction. The metamorphosed ophiolitic melange is thought to represent successfully subducted melange emplaced during the final phase (Miocene) of continental collision.