Geology, geochemistry, and evolution of the Divrigi and Kuluncak ophiolitic melanges, with reference to serpentinites in east-central Turkey

Abstract

The Divrigi and Kuluncak ophiolitic melanges are located in central Anatolia in the Tauride ophiolite belt. The stratigraphic sequence in the Divrigi ophiolitic melange includes, from bottom to top, the Upper Jurassic-Lower Cretaceous Akdag limestone, Upper Cretaceous Calti ultramafic rocks, and the Curek listwaenite. The Divrigi ophiolitic melange is intruded by the Late: Cretaceous-Eocene Murmano pluton. The above stratigraphic sequence is followed by the Eocene-Paleocene Ekinbasi metasomatite and the Quaternary Kilise Formation. The oldest sequence of rocks in Kuluncak ophiolitic melange in the Guvenc area is the Karadere serpentine/ultramafic body overlain successively by the Kurtali gabbro, Gundegeikdere radiolarite, the Guvenc listwaenites, and the Buldudere Formation. The of these units are Lute Cretaceous in age. The Karamagra siderite deposit in the Hekimhan area probably was formed in the Lower Cretaceous at the contact between Calti ultramafic rocks and the Buldudere Formation. Thr: Kuluncak ophiolitic melange was intruded by a subvolcanic trachyte in the Late Cretaceous. The Eocene-Paleocene Konukdere metasomatite, the Miocene Yamadag volcanic rocks, and Quaternary slops deposits are late in the stratigraphic sequence in the Guvenc area. The Kuluncak ophiolitic melange in the Karakuz area is similar to that at Guvenc: however, gabbro, radiolarite, and Miocene volcanic rocks are not present. The Miocene is represented ly the Ciritbelen Formation at Karakuz and the Karakuz iron deposit is hosted by a Late Cretaceous subvolcanic trachyte. The rare-earth and trace-element concentration of serpentinite in the Divrigi and Kuluncak ophiolitic melanges indicate that all of the ultramafics and their alteration products were derived From a MORB, which was depleted in certain elements and oxides. The results expressed in this study support the idea that the Divrigi and Kuluncak ophiolitic melanges within the Tauride ophiolite belt originated from Northern Tauride oceanic lithosphere (Poisson, 1986), instead of a northern branch of Neo-Tethys (Sengor and Yilmaz, 1981).