Melange genesis and ophiolite emplacement related to subduction of the northern margin of the Tauride-Anatolide continent, central and western Turkey

The Tauride-Anatolide continent, stretching for c. 900 km across western and central Turkey, is one of the world's best example of a subducted, exhumed passive margin within a collisional orogen. Twelve widely separated areas were studied and correlated to develop a new platetectonic model. A metamorphosed, rifted continental margin of Triassic-Lower Cretaceous age (Tauride-Anatolide platform) is overlain by Upper Cretaceous (Cenomanian-Lower Maastrichtian) pelagic sediments and then by both tectonic melange (subduction complexes) and sedimentary melange (foredeep gravity complexes). The melanges are overthrust by unmetamorphosed ophiolitic rocks, commonly peridotites with swarms of diabase/gabbro dykes, and are underlain by metamorphic soles. New geochemical evidence from basaltic blocks in the melange indicates predominantly subduction influenced, within-plate and mid-ocean ridge-type settings. The dykes cutting the ophiolites were probably intruded during early-stage intra-oceanic arc genesis. The metamorphosed continental margin, melanges and ophiolites in the north (Anatolides) are correlated with unmetamorphosed equivalents in the Taurides further south (e.g. Beyşehir and Lycian nappes). Oceanic crust of Triassic-Late Cretaceous age formed between the Gondwana-related Tauride-Anatolide continent in the south and the Eurasia-related Sakarya microcontinent in the north. Following Late Triassic-Early Cretaceous passive margin subsidence, the continental margin was covered by Cenomanian-Turonian pelagic carbonates (c. 98-90 Ma). Ophiolites formed in an intra-oceanic subduction zone setting in response to northward subduction, probably within a two-stranded ocean, with the Inner Tauride ocean in the SE and the Izmir-Ankara-Erzincan ocean in the north/NW. Metamorphic soles relate to intra-oceanic subduction (c. 95-90 Ma). Oceanic sedimentary/igneous rocks accreted to the advancing supra-subduction oceanic slab. The Tauride-Anatolide continental margin then underwent diachronous collision with the trench (c. 85 Ma), deeply subducted and metamorphosed at HP/LT (c. 80 Ma). Accretionary, ophiolitic and exhumed HP/LT rocks were gravity reworked into a southward-migrating flexural foredeep and progressively overridden (c. 70-63 Ma). Slices of the upper part of the platform and its margin detached and were thrust southwards as the (Tauride) Lycian and Beyşehir nappes, together with regional-scale ophiolites. The continental margin and melange were simultaneously exhumed during Maastrichtian-Early Paleocene (70-63 Ma) and transgressed by shallow-water sediments, beginning in the Late Maastrichtian in the east (c. 64 Ma) and the Mid?-Late Paleocene (c. 60 Ma) further west. Remnant oceanic crust was consumed during Early Cenozoic time, followed by Mid Eocene (45-40 Ma) diachronous continental collision and a second phase of regional deformation. Rather than being progressive there were two stages of collision: first, Upper Cretaceous ophiolite emplacement driven by continental margin-subduction trench collision, and secondly Eocene collision of the Tauride and Sakarya/Eurasian continents. © The Geological Society of London 2009

Permian–Recent palaeogeographical and tectonic development of Anatolia: some recent contributions

[No abstract available

Late palaeozoic-early cenozoic tectonic development of southern turkey and the easternmost mediterranean region: Evidence from the inter-relations of continental and oceanic units

Reconstructions of the Anatolian continent and adjacent areas assume the existence of one or more continental fragments during Mesozoic-Early Cenozoic time. These rifted from North Africa (Gondwana) during the Triassic, drifted across the Mesozoic Tethys and collided with Eurasia during latest Cretaceous-Paleocene time. Current reconstructions range from a regional-scale Tauride-Anatolide continent with oceanic basins to the north and south, to numerous rifted continental fragments separated by small oceanic basins. Field-based evidence for the inter-relations of the continental blocks and associated carbonate platforms is discussed and evaluated here, especially to distinguish between sutured oceans and intra-continental convergence zones. Several crustal units are restored as different parts of one large Tauride-Anatolide continent, whereas several smaller crustal units (e.g. Kirşehir massif; Bitlis/Pütürge and Alanya/ Kyrenia units) are interpreted as continental fragments bordered by oceanic crust. We infer a relatively wide I?zmir-Ankara-Erzincan ocean in the north and also a wide South Neotethyan ocean in the south. Several smaller oceanic strands (e.g. Inner Tauride ocean, Berit ocean and Alanya ocean) were separated by continental fragments. Our proposed reconstructions are shown on palaeotectonic maps for Late Permian to Mid-Miocene. The reconstructions have interesting implications for crustal processes, including ophiolite genesis and emplacement. © The Geological Society of London 2013

Overview of the Palaeozoic-Neogene evolution of Neotethys in the Eastern Mediterranean region (Southern Turkey, Cyprus, Syria)

Valid palaeotectonic and palaeogeographical reconstructions of the easternmost Mediterranean and adjacent region involve a long-lived Tethys (Rheic, Palaeotethyan and Neotethyan oceans), northward subduction beneath Eurasia and rifting of continental fragments from Gondwana. Rifted microcontinents bordering Gondwana were separated (from south to north) by the Southern Neotethyan ocean, the Berit ocean (new name), the Inner Tauride ocean and the İzmir-Arkara-Erzincan ocean. Mid-Permian to Mid-Triassic pulsed rifting culminated in Late Triassic-Early Jurassic spreading of the Southern Neotethyan oceans (the main focus here). After Early-Mid-Jurassic passive subsidence, the Late Jurassic-Early Cretaceous was characterized by localized alkaline, within-plate magmatism related to plume activity or renewed rifting. Late Cretaceous ophiolites formed above subduction zones in several oceanic basins. Ophiolites were emplaced southwards onto the Tauride and Arabian platforms during the latest Cretaceous. The Southern Neotethys sutured with the Arabian margin during the Early-Middle Miocene, while oceanic crust remained in the Eastern Mediterranean further west. The leading edge of the North African continental margin, the Eratosthenes Seamount, collided with a subduction trench south of Cyprus during the Late Pliocene-Pleistocene, triggering rapid uplift. Coeval Plio-Quaternary uplift of the Taurides may relate to break-off or delamination of a remnant oceanic slab. © 2012 EAGE/Geological Society of London

Tectonic evolution of the South Tethyan ocean: Evidence from the Eastern Taurus Mountains (Elazig region, SE Turkey)

Geological information from the Eastern Taurus Mountains, part of the Tethyan (South Neotethyan) suture zone exposed in the Elazig 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 Ispendere, 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. © The Geological Society of London 2007

The Berit transect of the Tauride thrust belt, S Turkey: Late Cretaceous-Early Cenozoic accretionary/collisional processes related to closure of the Southern Neotethys

We report on an integrated study of a critical segment of the Tauride thrust belt in SE Turkey (Berit area). Units related to two sutures are exposed in the northerly and southerly parts of the area studied. In the north the Upper Cretaceous Binboga Melange reflects the closure of a northerly Mesozoic oceanic basin. In the south, contrasting units document the closure of the Southern Neotethys. In the south, the Berit (or Göksun) ophiolite formed as an incipient oceanic arc within the Southern Neotethys during the Late Cretaceous (c.90 Ma). Intercalated amphibolite-granulite facies rocks may record a dismembered metamorphic sole. An underlying meta-sedimentary/meta-volcanic unit is interpreted as accreted continental rift and oceanic seamount lithologies. The Berit ophiolite was accreted to the Tauride active continental margin to the north around 85 Ma and was then intruded by calc-alkaline granites (c.70-85 Ma). Northerly margin units were exhumed and covered by shelf-carbonate sediments during latest Cretaceous-Early Cenozoic time. Northward subduction during the mid-Cenozoic (c.45 Ma) resulted in back-arc extension along the Tauride active margin and subduction-influenced volcanism, possibly controlled by slab roll-back. During Oligocene-Early Miocene time the Southern Neotethys closed and the Tauride active margin was telescoped to create the present south-vergent thrust stack. This was accompanied by mass wasting of the advancing allochthon to form sub-aqueous frontal olistostromes. The Arabian platform was over-ridden by Mid-Miocene time, followed by left-lateral strike-slip along the East Anatolian Fault zone, as Anatolia began to escape westwards towards the Aegean Sea. © 2005 Elsevier Ltd. All rights reserved

Erratum to "The Berit transect of the Tauride thrust belt, S Turkey: Late Cretaceous-Early Cenozoic accretionary/collisional processes related to closure of the Southern Neotethys" [Journal of Asian Earth Sciences 27 (2006) 108-145] (DOI:10.1016/j.jseaes.2005.02.004)

[No abstract available

Subduction, ophiolite genesis and collision history of Tethys adjacent to the Eurasian continental margin: New evidence from the Eastern Pontides, Turkey

This paper presents several types of new information including U-Pb radiometric dating of ophiolitic rocks and an intrusive granite, micropalaeontological dating of siliceous and calcareous sedimentary rocks, together with sedimentological, petrographic and structural data. The new information is synthesised with existing results from the study area and adjacent regions (Central Pontides and Lesser Caucasus) to produce a new tectonic model for the Mesozoic-Cenozoic tectonic development of this key Tethyan suture zone.The Tethyan suture zone in NE Turkey (Ankara-Erzincan-Kars suture zone) exemplifies stages in the subduction, suturing and post-collisional deformation of a Mesozoic ocean basin that existed between the Eurasian (Pontide) and Gondwanan (Tauride) continents. Ophiolitic rocks, both as intact and as dismembered sequences, together with an intrusive granite (tonalite), formed during the Early Jurassic in a supra-subduction zone (SSZ) setting within the İzmir-Ankara-Erzincan ocean. Basalts also occur as blocks and dismembered thrust sheets within Cretaceous accretionary melange. During the Early Jurassic, these basalts erupted in both a SSZ-type setting and in an intra-plate (seamount-type) setting. The volcanic-sedimentary melange accreted in an open-ocean setting in response to Cretaceous northward subduction beneath a backstop made up of Early Jurassic forearc ophiolitic crust. The Early Jurassic SSZ basalts in the melange were later detached from the overriding Early Jurassic ophiolitic crust.Sedimentary melange (debris-flow deposits) locally includes ophiolitic extrusive rocks of boninitic composition that were metamorphosed under high-pressure low-temperature conditions. Slices of mainly Cretaceous clastic sedimentary rocks within the suture zone are interpreted as a deformed forearc basin that bordered the Eurasian active margin. The basin received a copious supply of sediments derived from Late Cretaceous arc volcanism together with input of ophiolitic detritus from accreted oceanic crust.Accretionary melange was emplaced southwards onto the leading edge of the Tauride continent (Munzur Massif) during latest Cretaceous time. Accretionary melange was also emplaced northwards over the collapsed southern edge of the Eurasian continental margin (continental backstop) during the latest Cretaceous. Sedimentation persisted into the Early Eocene in more northerly areas of the Eurasian margin.Collision of the Tauride and Eurasian continents took place progressively during latest Late Palaeocene-Early Eocene. The Jurassic SSZ ophiolites and the Cretaceous accretionary melange finally docked with the Eurasian margin. Coarse clastic sediments were shed from the uplifted Eurasian margin and infilled a narrow peripheral basin. Gravity flows accumulated in thrust-top piggyback basins above accretionary melange and dismembered ophiolites and also in a post-collisional peripheral basin above Eurasian crust. Thickening of the accretionary wedge triggered large-scale out-of-sequence thrusting and re-thrusting of continental margin and ophiolitic units. Collision culminated in detachment and northward thrusting on a regional scale.Collisional deformation of the suture zone ended prior to the Mid-Eocene (~45 Ma) when the Eurasian margin was transgressed by non-marine and/or shallow-marine sediments. The foreland became volcanically active and subsided strongly during Mid-Eocene, possibly related to post-collisional slab rollback and/or delamination. The present structure and morphology of the suture zone was strongly influenced by several phases of mostly S-directed suture zone tightening (Late Eocene; pre-Pliocene), possible slab break-off and right-lateral strike-slip along the North Anatolian Transform Fault.In the wider regional context, a double subduction zone model is preferred, in which northward subduction was active during the Jurassic and Cretaceous, both within the Tethyan ocean and bordering the Eurasian continental margin. © 2014 Taylor & Francis.Natural Environment Research Council: IMF01000

Northern Dobrogea and the Crimean Mountains: The Key Areas in the Tectonic Evolution of the Black Sea Basin

International audienceThe work poses the question about the impact of inherited structures in the Black Sea back-arc basin (BAB) tectonic evolution. The new structural analysis of the Northern Dobrogea (ND) and the Crimean Mountains (CM) shows that the origins of structural patterns of both regions are in close relationship with deep faults/or fault zones. The comparative analyses of structures, of tectonic stages and their duration allow us to better understand the connections in time and space between the ND and the CM, against the back-ground of the long-living subduction. In particular during: (1) the Cimmerian orogeny; (2) the opening of the BS and (3) the inversion of the BS during the Cenozoic shortening