A new model for the late Palaeozoic—Mesozoic tectonic evolution of Iran and implications for Oman

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Abstract
It has been suggested that in a number of places such as Greece, Turkey, the Central Pamirs, and Thailand Neo-Tethys may have opened as a back-arc basin above a Palaeo-Tethyan subduction zone. The purpose of this paper is to test a similar suggestion for Oman. I review the late Palaeozoic to end-Mesozoic tectonic evolution of the Middle Eastern Tethysides in terms of a new tectonic model, whose main tenet is to regard the late Palaeozoic to Late Triassic basements of the Pontide/Dzirula/Adzharia-Trialeti/Arvin-Karabagh/Sanandaj — Sirjan zones collectively as a NNE-facing Palaeo-Tethyan magmatic arc, here named the ‘Podataksasi arc’ (or ‘zone’) whose Jurassic—Cretaceous movement with respect to Eurasia was responsible for much of the coeval deformation in Iran and Transcaucasia. The late Palaeozoic deformation of the Omani basement is regarded as a part of the retroarc fold and thrust belt of this arc and therefore independent of the Hercynides in Europe and NW Africa. The arc may have been compressional in late Carboniferous to possibly early Permian time and turned extensional in the earlier middle Permian. As a result, it rifted from NE Gondwana-Land, opening, successively, the Hawasina basin in the middle Permian and the main Neo-Tethyan ocean in the Triassic, together forming the ‘Omani Neo-Tethyan back-arc basin complex’. Nearly all of the tectonic and magmatic characteristics of this basin complex are compatible with a back-arc basin interpretation, except perhaps the anomalously far inland location of the initial rift axis. A rather complete Mesozoic tectonic history of the entire Middle Eastern Tethysides is given to justify the model presented.