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Closure of S Neotethys in the E Mediterranean region, exemplified by the tectonic development of the Kyrenia active margin/collisional lineament, N Cyprus

, , , , and . European Geosciences Union General Assembly, (17th-22nd April 2016)

Abstract

Active margin processes including subduction, accretion, arc magmatism and back-arc extension play a key role in the diachronous, still incomplete closure of the S Neotethys. The S Neotethys rifted along the present-day Africa-Eurasia continental margin during Late Triassic and, after sea-floor spreading, began to close related to northward subduction during Late Cretaceous. The northern, active continental margin of the S Neotethys bordered several rifted continental fragments. The present-day convergent margin ranges from still subaqueous (e.g. Mediterranean Ridge) to subaerial and is variably obscured by microcontinent-continent collision (e.g. SE Turkey). An excellent, subaerial record of convergent margin-early stage collisional processes are exposed in the Kyrenia Range, N Cyprus; a result of strong uplift during the last ca. 2.5 Ma (Pleistocene). This likely resulted from collision of a continental promontory of N Africa (Eratosthenes Seamount) with the S Neotethyan active margin. A multi-stage convergence history is revealed by a combination of mainly field structural, sedimentological and igneous geochemical studies. Initial Late Cretaceous convergence resulted in burial metamorphism, possibly related to the collision, then rapid exhumation of a continental fragment (stage 1). During the latest Cretaceous-Palaeogene, the Kyrenia lineament was characterised by subduction-influenced magmatism and syn-tectonic deposition. Early-Mid Eocene, S-directed thrusting and folding (stage 2) was likely influenced by final closure of the Izmir-Ankara-Erzincan ocean to the north (‘N Neotethys’). Convergence continued during the Neogene, dominated by deep-water terrigenous gravity-flow accumulation. Further S-directed compression took place during Late Miocene-earliest Pliocene (stage 3) in an oblique left-lateral stress regime, probably influenced by collision of the Tauride and Arabian continents to the E. Strong uplift of the active margin took place during the Pleistocene related to incipient continental collision (stage 4), as documented by a downward-younging flight of marine and continental terrace deposits. Each of the four above main deformation stages records an interruption of relatively steady state convergence by a collisional event within the wider region, with interesting regional implications.

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