The role of the 'Zvornik suture' for assessing the number of Neotethyan oceans: Surface - subsurface constraints on the fossil plate margin (Vardar Zone vs. Inner Dinarides)

Abstract

The balancing exercise of the "single-ocean model? and reexamination of Jurassic paleogeographic conditions and tectonic interaction allowed the reconstruction of the mosaic of independent microplate margins and sutured northwestern Tethyan realm (Vardar Ocean}. The overprinted Mesozoic convergent margin referred to as the 'Zvornik suture? was of special interest in the reconstruction of the displaced ophiolite belts of Dinarides and Vardar Zone. The surface-subsurface constraints of these mixed crustal units, in particular the polyphase strike-slip character of the 'Zvornik suture? yields the presence of at least two of Neotethyan basins extrapolated in the vicinity of the northwestern segment of this paleosuture. The restoration and synopsis shows a limited capability for obduction-related emplacement of the Vardar oceanic lithosphere (West Vardar Zone} accounting the polyphased strike-slip tectonics. The balancing and the proposed tectonic/paleogeographic reconstruction does not exclude obduction, but it shows a limited capability with much shorter across-strike width of the highly-deformed West Vardar ophiolite. The presence of the two distinct autochthonous Tethyan oceans divided by this important dextral strike-slip fault zone is suggested: The Inner Dinaric-( Mirdita-Pindos) Ocean or Dinaric Tethys (identified by the Inner Dinaric Ophiolite Belt) and the Vardar Ocean (identified by the West Vardar Zone). The West Vardar Zone remains to be a subzone of the principal composite Neotethyan suture referred to as the Vardar Zone s.s., whereas the Dinaric Tethys have been (re)incorporated to the area of Dinarides (Adria microplate). The northern segments of these two landlocked basins were on both sides of the Inner Dinaridic continental ridge (referred to as the Drina-Ivanjica block), divided by the protracted strike-slip activity of the 'Zvornik suture?.

The role of the pre-Alpine polycrystalline basement in the paleogeographic configuration of multiple Neotethyan oceanic basins

“…3a and 4). Across the opposite side of the Jurassic 'Zvornik suture', in line with the closure of the Neotethys or Vardar Ocean, the West Vardar were ophiolites obducted onto the Adria passive margin (Spahić and Gaudenyi, 2020c). The East Vardar Zone in North Macedonia was at the back of the Pelagonian basement block, whereas the late Paleocene -Lower Miocene shortening (underthrusting of Apulia beneath Pelagonian block) closed the Pindos Ocean (Xypolias et al, 2008 and references therein).…”

“…Bernoulli, 2001 and references therein;van Hinsbergen et al, 2020). Both concepts nevertheless illustrate the Variscan involvement of the Adria (Pamić & Jurković, 2002) that in turn has not been fully validated across the Dinarides (Okay et al, 2006;Spahić et al, 2020c). The main problem of the eventual Variscan interference revolves around the age of the metamorphic overprint has often been dated as of the dominant Alpine relevance i.e.…”

“…In the early Mesozoic paleogeographic context, during a limited Jurassic interval, several oceans (oceanic lithosphere developed) were identified in the area of the Western Balkan countries (Fig. 5; also, in Dimitrijević, 2001;Karamata, 2006;Stampfli & Kozur, 2006;Spahić & Gaudenyi, 2020c). The developments of the NW Neotethys or Vardar Ocean corresponds to the crustal extension of the Adria microplate and the formation of, at least, two marginal micro-oceans: the "Dinaric Tethys" seems to be a kind of "Red Sea-type" narrow landlocked ocean (Robertson & Karamata, 1994).…”