Testing models of Late Palaeozoic–Early Mesozoic orogeny in Western Turkey: support for an evolving open-Tethys model

Abstract

Field evidence from north-south transects tests three tectonic models for Tethys in Western Turkey for when a Late Palaeozoic ocean was closing and an Early Mesozoic ocean opening. In Model 1, a Palaeozoic ocean subducted southwards, rifting continental fragments from Gondwana and opening a Triassic Neo-Tethys to the south. Closure and collision occurred by latest Triassic time. In Model 2, a wide Palaeozoic Tethys subducted northwards with an active Eurasian margin and a passive Gondwana margin. The northern Gondwana margin rifted in the Triassic; fragments either remained nearby (Taurides) or drifted northwards (e.g. Karakaya) attached to a north-subducting plate. New oceanic crust replaced Palaeo-Tethys with Neotethys and back-arc marginal basins opened along the south Eurasian margin (e.g. Küre). In Model 3, a Palaeozoic ocean also subducted northwards opening wide marginal basins. A wide Southern Neotethys opened along the Gondwana margin. Rifted Eurasian (Anatolides) and Gondwana (Taurides) fragments collided in mid-Tethys by latest Triassic time. Field evidence from the Pontides supports north-dipping subduction models (Model 2 or 3 above). Key features are a south-vergent, HP-LT accretionary prism, magmatic arc and back-arc basin system bordering the Eurasian margin. Also, evidence from the Tauride Mountains favours Model 2 over Model 3. Critically, the Anatolides and Taurides appear to have a common history and were unlikely to have been located on opposite sides of Tethys, as in Model 3.

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

“…Throughout Late Palaeozoic to Early Cenozoic time Tethyan oceanic crust existed to the south of Eurasia. In many interpretations, the subduction polarity was consistently northwards throughout this time period (Adamia et al, 1981;Barrier & Vrielynck, 2008;Okay, Satır, & Siebel, 2006;Robertson & Dixon, l984;Robertson et al, 2005;Ustaömer & Robertson, 2010;Ustaömer, Robertson, Ustaömer, Gerdes, & Peytcheva, 2013). An alternative is that subduction was southwards during the Late Palaeozoic but switched to northwards during the later Mesozoic-Early Cenozoic (Şengör, 1984;Yılmaz, Tüysüz, Yiğitbaş, Genç, & Şengör, 1997).…”

Stable isotope-based reconstruction of Oligo-Miocene paleoenvironment and paleohydrology of Central Anatolian lake basins (Turkey)

“…The Cenozoic geodynamic history of the Eastern Mediterranean region was characterized by the interactions of several microcontinents, including the opening and closure of oceanic basins and parts of the Paratethys (e.g., Şengör & Yılmaz 1981;Şengör 1984, 1987Stampfli 2000;Robertson et al 2004). Post-Late Eocene closure of the Tethyan Ocean resulted in the development of the Pontides in the north and Taurides in the south.…”

Blueschists of the Amassia-Stepanavan Suture Zone (Armenia): linking Tethys subduction history from E-Turkey to W-Iran

“…In Turkey, the Intra-Pontide suture in the Sakarya Zone preserves Permo-Triassic subduction complexes Avagyan et al (2005), modified unconformably overlain by Jurassic sediments (e.g., Okay and Tüysüz 1999;Robertson et al 2004;Okay and Göncüoglu 2004). The Izmir-Ankara suture is underlined by Mid-to Upper Cretaceous HP-LT rocks.…”