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The Hekimhan Basin is here put forward as a type example of a globally important class of basin, known as a supra-ophiolite basin. Such basins form after the emplacement of ophiolitic (i.e. oceanic) rocks onto a passive continental margin, but long prior to continental collision. The Hekimhan Basin developed as part of the northern margin of the Tauride microcontinent during the collision and suturing of two Neotethyan oceans to the north, namely the Inner Tauride Ocean and the İzmir–Ankara–Erzincan ocean. The basin records two main stages of tectonic development, during latest Cretaceous to Late Eocene time. The first phase of basin development during the Late Cretaceous (Maastrichtian) began with the erosion of emplaced ophiolitic rocks, resulting in non-marine clastic sedimentation. Subsequently, the basin rapidly subsided, in response to inferred regional crustal extension, resulting in the deposition of hemipelagic marls and local sapropelic mudstones. The axial parts of the basin experienced alkaline, within-plate-type, basaltic volcanism. The Late Maastrichtian culminated in deposition of shallow-marine carbonates. Overlying Paleocene sediments are restricted to thin, localised, marine evaporates, associated with a low-angle unconformity. The second stage of basin development began during the Early Eocene with deposition of shallow-marine carbonates, coupled with localised basaltic volcanism, again of extensional type. The basin emerged during the Mid–Late Eocene in a late-stage collisional to post-collisional setting. Compressional deformation largely reflects post-suture tightening. A short-lived marine transgression occurred during the Mid-Miocene. The basin was later deformed by both left-lateral and right-lateral strike-slip. Several different tectonic models are considered, notably extension related to the northward pull of a still-subducting oceanic slab, and back-arc extension related to northward subduction of Neotethys (to the south). The first alternative is consistent with the development of adjacent supra-ophiolite basins (e.g. Ülükışla and Darende Basins), and also with supra-ophiolite basins elsewhere (e.g. SE Turkey; Balkans; Oman). [ABSTRACT FROM AUTHOR]

Abstract: The tectonic development of the northeast margin of the Korabi-Pelagonian continent and the adjacent Vardar ocean is discussed based on study of nine traverses across the former northeastern margin of the Korabi-Pelagonian continent, represented by the West Vardar subzone in the Republic of Macedonia. A detailed correlation of units is also made across the international border with Greece, coupled with regional comparisons. Precambrian–Palaeozoic units were metamorphosed and intruded by granitic rocks, followed by Mid-Triassic rifting and the construction of a carbonate platform bordering a Late Triassic–Early Jurassic ocean. Neritic deposition was followed by Late Jurassic (syn‐ or pre-Early Tithonian) subsidence with radiolarian and then terrigenous turbidite sedimentation. Overlying ophiolitic rocks are characterised by a relatively thin (<500m), laterally persistent (>200km N–S) sheet of sheared, blocky serpentinite (mainly mantle harzburgite), associated with ophiolite-derived debris flows. The emplaced ophiolitic rocks were subaerially weathered to form local Fe–Ni accumulations. Following marine transgression, a shallow-water carbonate–siliciclastic deposits, including coralgal reefs, accumulated during Late Tithonian–Early Cretaceous. After a hiatus, mixed terrigenous-carbonate gravity flows accumulated in deep water during the Late Cretaceous. The Vardar ocean opened during the Late Triassic–Early Jurassic separating the Korabi-Pelagonian and Serbo-Macedonian continents. Northeastward subduction created a Late Jurassic magmatic arc along the southern margin of the Serbo-Macedonian continent, while future ophiolites formed by supra-subduction zone spreading within the Vardar ocean. These ophiolites were emplaced in response to collision of the subduction trench with the Korabi-Pelagonian continent. The pre-Mesozoic basement detached and subducted undergoing high pressure–low temperature metamorphism during the Late Jurassic (Tithonian), followed by amphibolite/greenschist facies metamorphism and exhumation prior to the Late Cretaceous. A much reduced Vardar ocean survived into the Late Cretaceous until this finally closed during the latest Cretaceous–Early Cenozoic, triggering continental collision and thick-skinned folding/thrusting of the Pelagonian, Vardar and Serbo-Macedonian zones towards the W/SW. [Copyright &y& Elsevier]

The Eastern Mediterranean region exhibits a fascinating diversity of ophiolites and related oceanic magmatic units of mainly Triassic, Jurassic and Cretaceous age. Comparisons with the settings of modern oceanic lithosphere indicate that the various Eastern Mediterranean ophiolites have different origins and formed in a variety of tectonic settings. Some have argued that the largest ophiolites, of Jurassic and Cretaceous age (e.g. Troodos), formed at mid-ocean ridges. However, the widespread occurrence of andesitic extrusives, chemically “depleted” basalts and highly magnesian lavas (boninites), favour formation of most of the large, relatively intact ophiolites in the Eastern Mediterranean region above subduction zones rather than at mid-ocean ridges (MORs). Such ophiolites probably formed by spreading during the initial stages of intra-oceanic subduction, prior to the emergence of any major related oceanic arc. Supra-subduction-type ophiolites typically formed during short-lived periods (<5 Ma) of regional plate re-organisation. By contrast, most MOR-type oceanic crust was subducted, or is preserved only as dismembered thrust sheets or blocks in ophiolitic melange, commonly metamorphosed under high-pressure/low-temperature (HP/LT) conditions. However, MOR-type ophiolites are locally preserved (e.g. Jurassic Western-type Albanian ophiolite). Seamounts were preferentially accreted into melanges and record subduction of large areas of oceanic crust. Volcanic–sedimentary units of mainly Triassic age, including alkaline to MOR-type extrusives and radiolarites record rifting, transitional to spreading of Neotethyan ocean basins. Back-arc, intra-continental marginal basins of Triassic and Late Jurassic age developed within the northerly (Eurasian) continental margin (e.g. Jurassic Guevgueli ophiolite, N Greece). Ophiolites formed in these basins were exposed by uplift, without significant transport. Transform-influenced ophiolites are occasionally preserved (e.g. Late Cretaceous Tekirova ophiolite, SW Turkey). Metamorphic soles reflect tectonic displacement of oceanic lithosphere while still hot, near a spreading centre (whether of mid-ocean ridge or supra-subduction type). The Eastern Mediterranean subduction-type ophiolites, of both Jurassic and Cretaceous age, were rooted in several coeval Neotethyan oceanic basins, separated by microcontinents and cannot be interpreted as vast, far traveled thrust sheets derived (at different times) from a single, palaeogeographically simple Tethyan oceanic basin. [Copyright &y& Elsevier]

Focuses on siliceous and hemipelagic sediments within extrusives of the Guevgueli Ophiolite in Northern Greece. Discussion about their palaeo-environmental significance; Presentation of chronostratigraphic information; What chronostratigraphic data was based on; How radiolarian sediments were deposited; Consistency of information.

Palaeomagnetic results from 27 sites at five localities within the dismembered Bae¨r–Bassit ophiolite of northern Syria are presented. The ophiolite forms part of a series of thrust sheets emplaced over Mesozoic carbonates of the Arabian platform in the middle Maastrichtian. A positive inclination-only area-wide tilt test applied to four locality mean remanences and positive fold and reversal tests from palaeohorizontal units (pillow lavas, lava flows) within one of these localities indicate that the ophiolite preserves pre-deformation magnetisations. Variable directions of remanence between localities demonstrate that the ophiolite has experienced extreme relative anticlockwise rotations on a kilometric scale. Within the most extensively sampled ophiolite massif (Bassit sheet) there is a progressive increase in rotation from north to south. The southernmost units at the lowest structural level in the imbricate thrust stack record the highest rotation (exceeding 200°). Although tectonic rotation during imbricate thrusting has been reported in a number of orogenic belts, the pattern of rotations in the Bassit sheet is difficult to explain by differential thrust sheet rotation. Instead, regional comparisons with the Hatay ophiolite of southern Turkey and the Troodos ophiolite of Cyprus suggest that a significant component of rotation may be ascribed to intraoceanic deformation of a coherent region of oceanic crust within the southern Neotethyan basin prior to ophiolite emplacement. The partially rotated Bae¨r–Bassit ophiolite was then emplaced and structurally dismembered by thrust faulting. During the Late Tertiary the ophiolitic units were further rotated during the initiation and development of a major sinistral strike-slip fault zone, linking the Cyprus subduction zone to the Dead Sea Transform system. The extreme rotations observed in the study are therefore of composite origin, and reflect the complex development of structural fabrics within the ophiolite. [Copyright &y& Elsevier]

Abstract: New structural data are presented and interpreted for the Cretaceous Hatay ophiolite, which was emplaced onto the Arabian continental margin during latest Cretaceous (Maastrichtian) time. Although lacking a preserved metamorphic sole, a thick serpentinitic basal shear zone provides evidence of emplacement kinematics, whilst structures developed in an extensive Cenozoic sedimentary cover help to constrain the nature of post-emplacement deformation. Combining field structural measurements with palaeostress analyses enables several discrete structural events to be recognised, of which three appear to pre-date the Cenozoic sedimentary cover. The earliest event involved extension parallel to the ophiolitic sheeted dyke complex and relates to oceanic spreading whereas the second and the third events relate to compression and strike-slip during intra-oceanic displacement, or emplacement of the ophiolite onto the Arabian continental margin. Some structures at the base of or within the ophiolite that were previously attributed to sea-floor spreading processes (e.g. “oceanic detachment faults”) are more likely to have formed during subsequent ophiolite displacement/emplacement and post-emplacement formation of the regional Hatay Graben. [Copyright &y& Elsevier]

Abstract: Insights into tectonic processes operating in ancient ocean basins are provided by analyses of fragments of oceanic lithosphere preserved as ophiolites during collisional orogenesis. Here we present a palaeomagnetic analysis of the Upper Cretaceous Hatay (Kizil Dağ) ophiolite of Turkey that provides evidence for intraoceanic microplate rotation and variations in ridge axis orientation in a Neotethyan ocean basin. Magnetizations at 46 sites are shown to be pre-deformational in origin and rotated from the relevant reference direction. A net tectonic rotation approach to the analysis of the data provides information on permissible net rotation poles and angles and allows uncertainties in input vectors to be considered. Results demonstrate that all levels of the ophiolite have been rotated anticlockwise by angles in excess of 90° around steeply inclined axes. The Hatay ophiolite formed in the same supra-subduction zone spreading system as the Troodos ophiolite (Cyprus), which is known to have rotated 90° anticlockwise in an intraoceanic setting in the Late Cretaceous to Early Eocene. By considering our results in the context of the known timing of the Troodos rotation, we infer that 50–60° of rotation of the Hatay ophiolite took place as part of an areally extensive “Troodos microplate”. This phase of rotation was triggered by initial impingement of the Arabian continental margin with the Neotethyan subduction trench, consistent with models for modern day oceanic microplate rotation in complex convergent plate boundaries. The Hatay ophiolite then became detached from the actively rotating microplate and was emplaced onto the Arabian margin in the Maastrichtian, undergoing a further 30–40° of anticlockwise rotation during thrusting. Back-stripping of rotations allows correction of the Hatay sheeted dykes to their initial orientations. The restored dyke trend of 020° differs from that inferred previously for the Troodos sheeted dyke complex, demonstrating a primary variation in orientation of Neotethyan spreading axes. Such variability is commonly observed in modern spreading systems in marginal basins; these may act as analogues for the supra-subduction zone spreading inferred for many ophiolites. [Copyright &y& Elsevier]