An active bivergent rolling-hinge detachment system: Central Menderes metamorphic core complex in western Turkey

Two symmetrically arranged detachment systems delimit the central Menderes metamorphic core complex and define a bivergent continental breakaway zone in the Anatolide belt of western Turkey. Structural analysis and apatite fi ssion-track thermochronology show that a large east-trending syncline withi n the Alpine nappe stack in the central part of the orogen is related to la te Miocene-early Pliocene to recent core-complex formation. The syncline fo rmed as a result of two opposite-facing rolling hinges in the footwalls of each of the two detachments. Back-rotation of the syncline limbs suggests t hat the detachments rotated from an initial dip of 50 degrees -60 degrees t o a currently shallow orientation of 0 degrees -20 degrees.