U–Pb and 40Ar–39Ar geochronology of the ophiolites and granitoids from the Tauride belt: Implications for the evolution of the Inner Tauride suture

Abstract

The Inner Tauride ocean separated the Tauride-Anatolide Block from the Central Anatolian Crystalline Complex. This oceanic basin was consumed as a result of north-dipping subduction and closed during the latest Cretaceous to early Cenozoic times. Subduction-related magmatism and metamorphism occurred at different stages during the closure of the Inner Tauride ocean. The ophiolites and granitoids record the tectonic events. In this paper, we present new U–Pb zircon age determinations by LA-MC–ICP-MS and 40Ar–39Ar age dating of selected ophiolites (Mersin, Pozantı-Karsantı, Pınarbaşı and Divriği) and granitoids (Horozköy and Divriği) along the Inner Tauride suture zone. The results show that: (i) the crystallization age of SSZ oceanic crust is ∼89Ma and the magmatic activity continued until just prior to ophiolite emplacement onto the Tauride-Anatolide platform during the latest Cretaceous (Maastrichtian), (ii) the timing of intraoceanic thrusting/subduction is constrained as ∼89Ma, which is consistent with steady-state subduction in a forearc tectonic setting, (iii) the timing of collision of the Tauride-Anatolide passive margin with the subduction trench of the Inner Tauride ocean and subsequent slab break-off occurred from 76 to 67Ma, and (iv) the timing of continent–continent collision between the Central Anatolian Crystalline Complex and the Tauride-Anatolide Block is constrained as Eocene (50–49Ma). The first three tectonic stages overlap each other during the closure of the Inner Tauride oceanic basin. ‘Soft’ collision of the subduction trench with the passive margin was followed by hard-collision and suture tightening ∼8–10My later.