Geology,Geochemistry, and Evolution of the Divrigi and Kuluncak Ophiolitic Melanges,with Reference to Serpentinites in East-Central Turkey

The Divrigi and Kuluncak ophiolitic mélanges are located in central Anatolia in the Tauride ophiolite belt. The stratigraphic sequence in the Divrigi ophiolitic mélange includes, from bottom to top, the Upper Jurassic-Lower Cretaceous Akdag limestone, Upper Cretaceous Çalti ultramafic rocks, and the Curek listwaenite. The Divrigi ophiolitic mélange 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 mélange in the GuvenÇ area is the Karadere serpentine/ultramafic body overlain successively by the Kurtali gabbro, Gundegcikdere radiolarite, the GuvenÇ listwaenites, and the Buldudere Formation. All of these units are Late Cretaceous in age. The Karamagra siderite deposit in the Hekimhan area probably was formed in the Lower Cretaceous at the contact between Çalti ultramafic rocks and the Buldudere Formation. The Kuluncak ophiolitic mélange was intruded by a subvolcanic trachyte in the Late Cretaceous. The Eocene-Paleocene Konukdere metasomatite, the Miocene Yamadag volcanic rocks, and Quaternary slope deposits are late in the stratigraphic sequence in the GuvenÇ area.

The Kuluncak ophiolitic mélange in the Karakuz area is similar to that at GuvenÇ; however, gabbro, radiolarite, and Miocene volcanic rocks are not present. The Miocene is represented by the Ciritbelen Formation at Karakuz and the Karakuz iron deposit is hosted by a Late Cretaceous subvolcanic trachyte.

The rareearth and trace-element concentration of serpentinite in the Divrigi and Kuluncak ophiolitic mélanges 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 mélanges 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).