Late Cretaceous–Early Eocene tectonic development of the Tethyan suture zone in the Erzincan area, Eastern Pontides, Turkey

Abstract

Six individual tectonostratigraphic units are identified within the İzmir–Ankara–Erzincan Suture Zone in the critical Erzincan area of the Eastern Pontides. The Ayıkayası Formation of Campanian–Maastrichtian age is composed of bedded pelagic limestones intercalated with polymict, massive conglomerates. The Ayıkayası Formation conformably overlies the Tauride passive margin sequence in the Munzur Mountains to the south and is interpreted as an underfilled foredeep basin. The Refahiye Complex, of possible Late Cretaceous age, is a partial ophiolite composed of ~75% (by volume) serpentinized peridotite (mainly harzburgite), ~20% diabase and minor amounts of gabbro and plagiogranite. The complex is interpreted as oceanic lithosphere that formed by spreading above a subduction zone. Unusual screens of metamorphic rocks (e.g. marble and schist) locally occur between sheeted diabase dykes. The Upper Cretaceous Karayaprak Mélange exhibits two lithological associations: (1) the basalt + radiolarite + serpentinite association, including depleted arc-type basalts; (2) the massive neritic limestone + lava + volcaniclastic association that includes fractionated, intermediate-composition lavas, and is interpreted as accreted Neotethyan seamount(s). The several-kilometre-thick Karadağ Formation, of Campanian–Maastrichtian age, is composed of greenschist-facies volcanogenic rocks of mainly basaltic to andesitic composition, and is interpreted as an emplaced Upper Cretaceous volcanic arc. The Campanian–Early Eocene Sütpınar Formation (~1500 m thick) is a coarsening-upward succession of turbiditic calcarenite, sandstone, laminated mudrock, volcaniclastic sedimentary rocks that includes rare andesitic lava, and is interpreted as a regressive forearc basin. The Late Paleocene–Eocene Sipikör Formation is a laterally varied succession of shallow-marine carbonate and siliciclastic lithofacies that overlies deformed Upper Cretaceous units with an angular unconformity. Structural study indicates that the assembled accretionary prism, supra-subduction zone-type oceanic lithosphere and volcanic arc units were emplaced northwards onto the Eurasian margin and also southwards onto the Tauride (Gondwana-related) margin during Campanian–Maastrichtian time. Further, mainly southward thrusting took place during the Eocene in this area, related to final closure of Tethys. Our preferred tectonic model involves northward subduction, supra-subduction zone ophiolite genesis and arc magmatism near the northerly, Eurasian margin of the Mesozoic Tethys.

Middle Eocene paleomagnetic data from the eastern Sakarya Zone and the central Pontides: Implications for the tectonic evolution of north central Anatolia

“…[37] The oldest compressional regime (a) was the result of collision between the Pontides, Taurides, and the Kırşehir Block in the Early Cenozoic, after the Kırşehir massif indented northward into the Pontides, and following the final closure of the Neotethys Ocean in early Eocene times approximately 50 Myr ago [Şengör and Yılmaz, 1981;Tüysüz and Dellaloglu, 1992;Tüysüz et al, 1995;Kaymakcı et al, 2000Kaymakcı et al, , 2003aKaymakcı et al, , 2003bRice et al, 2006Rice et al, , 2009. The most important deformation stage is related to large-scale ophiolite emplacement, thrust faulting, and transpression.…”

“…It surrounds the Çankırı Basin and extends approximately in an E-W direction toward Reşadiye [Şengör and Yılmaz, 1981;Tüysüz andDellaloglu, 1992, 2001;Tüysüz et al, 1995;Kaymakcı et al, 2000Kaymakcı et al, , 2003aKaymakcı et al, , 2003b. Further north, in the Kargı Massif, ophiolitic mélanges of Campanian age occur as thin thrust slices [Yılmaz andTüysüz, 1984, 1988;Tüysüz, 1990;Yiğitbaş et al, 1990;Rice et al, 2006Rice et al, , 2009.…”

“…During the Late Mesozoic and Cenozoic, the northern Neotethys oceanic basin was progressively closed by northward subduction. This subduction was marked by the formation of a magmatic arc and fore-arc basins, and the emplacement of large ophiolitic mélanges that were thrust over the Taurides to the south and the Pontides to the north [Şengör and Yılmaz, 1981;Şengör, 1995;Okay and Tüysüz, 1999;Rice et al, 2006Rice et al, , 2009Robertson et al, 2009].…”

Alteration Zones Associated With Eocene Magmatism in the Olur (Erzurum) 9 Area, Eastern Pontides and Their Significance

“…The base metals and precious metals of the Eastern Pontides have for a long time drawn the attention of earth scientists (a) Geological evolution of the İzmir-Ankara-Erzincan suture zone in particular and it's continuation to the East Minor Caucasus are especially important (Okay, 1984;Evans and Hall, 1990;Okay and Şahintürk, 1997;Yılmaz et al, 1997;Okay and Tüysüz, 1999;Yılmaz et al, 2000;Hakyemez and Konak, 2001;Topuz et al, 2004;Okay et al, 2006;Rice et al, 2006;Konak and Hakyemez, 2008a;Rice et al, 2009;Rolland et al, 2009a, b;Çelik et al, 2011;Ustaömer and Robertson, 2010;Topuz et al, 2012;Ustaömer et al, 2012;Robertson et al, 2013), (b) Origin of Late Cretaceous massive sulphide deposits (Kraeff, 1963;Hirst and Eğin, 1979;Çağatay and Boyle, 1980;Akıncı, 1984), (c) Late CretaceousEocene porphyry Cu deposits, (Çağatay and Çağatay, 1978;Aral and Erler, 1981;Er et al, 1995;Soylu, 1999;Singer et al, 2008;Yiğit, 2006Yiğit, , 2009Oğuz, (d) Ophiolites and their emplacements along İzmir-AnkaraErzincan suture zone (Rice et al, 2006(Rice et al, , 2009Özen et al, 2008;Çolakoğlu et al, 2009Çolakoğlu et al, , Sarıfakıoğlu et al, 2009Parlak et al, 2013;…”

Doğu Pontidler’deki (KD Türkiye) Üst Maastrihtiyen- Paleosen Sığ Denizel Karbonat Istiflerinin Mikrofasiyesleri ve Bentik Foraminiferlerin Stratigrafik Dağılımı

“…The stratigraphic and structural development of the Eastern Pontides was described in Robinson et al (1995) , Yılmaz et al (1997) and Rice et al (2009).…”