Geological information from the Eastern Taurus Mountains, part of the Tethyan (South Neotethyan) suture zone exposed in the Elaziğ region, is used here to test existing tectonic hypotheses and to develop a new tectonic model. Five main tectonic stages are identified: (1) Mid-Late Triassic rifting-spreading of Southern Neotethys; (2) Late Cretaceous northward subduction-accretion of ophiolites and arc-related units; (3) Mid-Eocene subduction-related extension; (4) Early-Mid-Miocene collision and southward thrusting over the Arabian Foreland; (6) Plio-Quaternary, post-collisional left-lateral tectonic escape. During the Late Cretaceous (c. 90 Ma) northward intra-oceanic subduction generated regionally extensive oceanic lithosphere as the İspendere, Kömürhan, Guleman and Killan ophiolites of supra-subduction zone type. A northward-dipping subduction zone was activated along the northern margin of the ocean basin (Keban Platform), followed by accretion of Upper Cretaceous ophiolites in latest Cretaceous time. As subduction continued the accreted ophiolites and overriding northern margin (Keban Platform) were intruded by calc-alkaline plutons, still during latest Cretaceous time. The northern margin was covered by shallow-marine mixed clastic-carbonate sediments in latest Cretaceous-Early Palaeogene time. Northward subduction during the Mid-Eocene was accompanied by extension of the northern continental margin, generating large fault-bounded, extensional basins that were infilled with shallow- to deep-water sediments and subduction-influenced volcanic rocks (Maden Group). Thick debris flows (‘olistostromes’) accumulated along the oceanward edge of the active margin. The partly assembled allochthon finally collided with the Arabian continental margin to the south during Early-Mid-Miocene time in response to oblique convergence; the entire thrust stack was then emplaced southwards over the downflexed Arabian Foreland. Left-lateral strike-slip (tectonic escape) along the East Anatolian Fault Zone ensued.

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The Elaz~ region in SE Turkey comprises, in descending order, the Palaeozoic-Mesozoic Malatya-Keban platform, an ensimatic island arc unit (i.e. EIam~ magmatic rocks-YiJksekova complex), and ophiolitic rocks (i.e. K6mfirhan) of Late Cretaceous age. All of these were intruded by the Baskil granitic rocks. These tectonomagmatic-stratigraphic assemblages were emplaced over the Middle Eocene volcano-sedimentary Maden complex to the south during the evolution of the SE Anatolian orogen. The K6mfirhan ophiolite exhibits an intact ophiolite pseudostratigraphy. The base of this has been metamorphosed to amphibolite facies during intraoceanic subduction-thrusting. The amphibolitic rocks were intruded by synkinematic granitic rocks (Baskil magmatic rocks). The ensimatic island arc volcanic rocks are widely distributed in the region. The contact of the volcano-sedimentary unit with the underlying K6mfirhan ophiolite is a thrust dipping to the north. The rock assemblages of the volcano-sedimentary unit suggest formation of small volcanic edifices above a subduction zone, coupled with debris-flow deposits and volcaniclastic turbidites. The whole-rock and mineral chemistry of the K6mfirhan ophiolite and the ensimatic island arc volcanic rocks suggests that they represent a comagmatic tholeiitic suite, formed in the Late Cretaceous in a suprasubduction zone (SSZ) setting. The amphibolites beneath the K6mfirhan ophiolite indicate derivation from an island arc tholeiite (IAT) protolith. The geological and geochemical evidence from the Elaz~ region suggests the following evolutionary scenario. The K6mfirhan ophiolite was formed above a north-dipping subduction zone between the Arabian platform to the south and the Tauride platform to the north in Late Cretaceous (c. 90 Ma). An ensimatic island arc assemblage was then built on the SSZ-type crust. The metamorphic sole was formed by metamorphism of IAT-type basalts that were detached from the front of the overriding K6mfirhan ophiolite and then underplated. These units were then accreted to the base of the Tauride active margin to the north, where both units were cut by the Baskil granitic rocks around 85 Ma.

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The İspendere ophiolite forms part of the Tauride active continental margin assemblage in SE Anatolia. The ophiolite exhibits an intact oceanic lithosphere section and is intruded by Late Cretaceous calc-alkaline granites. The ophiolite comprises mantle tectonites, ultramafic to mafic cumulates, isotropic gabbros, isolated diabase dykes, a sheeted dyke complex, plagiogranite and volcanic rocks. The volcanics and the sheeted dyke complex exhibit (1) similar rare earth element patterns, with flat to light rare earth element depletion (La-Yb) N ¼ 0.71-1.14 and 0.65-1.22, (2) negative Nb anomalies and (3) flat-lying high field strength element trends. These features differ from a typical Normal-Mid Ocean Ridge Basalt fractionation trend and could have resulted from c. 15% partial melting of a previously depleted mantle source. The whole-rock chemistry and the mineral chemistry of the ultramafic to mafic cumulates [high Ca plagioclases (An 89 -81 ), magnesian olivines (Fo 88 -81 ) and clinopyroxenes (Mg# 90 -83 )] show that the primary magma of the plutonic suite is compositionally similar to modern island arc tholeiites. The available evidence suggests that the İspendere ophiolite formed at a northerly supra-subduction zone spreading centre of the Southern Neotethys, between the Taurides and the Bitlis-Pütürge metamorphic units, during the Late Cretaceous. Comparison with the adjacent Göksun, Kömürhan and Guleman ophiolites suggests that the İspendere ophiolite represents part of a single regional-scale sheet of oceanic lithosphere that was accreted to the base of Tauride active continental margin where it was cut by arc-type magmatic rocks.

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