A few remarks on the Triassic paleogeography and geodynamic link between the Dinarides an the Serbo-Macedonian unit

Darko Spahic,Tivadar Gaudenyi

doi:10.2298/gabp191212006s

Abstract

A recently recycled tectonic hypothesis in which the Serbo-Macedonian Unit rifted off during Ladinian from the Dinarides is tested. The Triassic rifting, according to this concept, led to the opening and the formation of a northwestern branch of Neotethys (=Vardar Ocean). Similar concept explains the developments within the Inner Hellenide allochoton (Serbo-Macedonian Unit and Pelagonides). The testing of early Alpine configuration in Serbia shows, however, that the two crystalline basement units have significant paleogeographic variances. The study moreover includes the differences in Paleozoic metamorphic grades between two inliers, their exhumation times, etc. The investigated pre-Triassic paleogeographic and geodynamic variances unambiguously contradict any connection before and during Triassic (Ladinian). In this regard, by using the available field data, and the juxtaposed Late Paleozoic Variscan tectonometamorphic differences, the paper underscores the large differences in the (pre)Triassic plate configurations and paleogeography. The synthesis displays the two separate positions of these microplates situated along with the length of this segment of the Triassic Eurasian continental margin.

Highlights

The highly complex configuration of the NW Neotethys (=Vardar Ocean) is recorded and dispalyed between the Apulia/Adria microplate (Dinarides) and a fragment of Euroasian foreland represented by the Serbo-Macedonian Unit (Fig. 1)
The essential question is the precise location of this segment of western Palaeotethys ocean or whether a Triassic imprint across Western balkans could belong to a rifted Neotethyan oceanic basin? Another important ambiguity is whether western Paleotethyan gulf was closed in the Triassic or the early Alpine Triassic transition into the Neotethys was rather smooth?
We provide a short comparison of the essential differences with a goal to outline the past position of a distal most segment of the “Dacia Terrane” referred as the Serbo-Macedonian Unit

Summary

Introduction

The highly complex configuration of the NW Neotethys (=Vardar Ocean) is recorded and dispalyed between the Apulia/Adria microplate (Dinarides) and a fragment of Euroasian foreland represented by the Serbo-Macedonian Unit (Fig. 1). Despite a long history of the early Alpine (Permian– Triassic) investigations (for a review see rObErTSON, 2012), there is no consensus on the Neotethyan evolution imprinted across the Western balkan countries and its ophiolite belts. The versatile reconstructions still struggle with the Permian-Triassic active plate margins The activity along these Paleotethyan active margin(s) would presumably affect the rifting and opening of the Triassic Tethyan ocean (or branches) in the back-arc position. Another important ambiguity is whether western Paleotethyan gulf (paleogeographically situated between Dinarides and Serbo-Macedonian Unit?) was closed in the Triassic or the early Alpine Triassic transition into the Neotethys was rather smooth? The essential question is the precise location of this segment of western Palaeotethys ocean or whether a Triassic imprint across Western balkans could belong to a rifted Neotethyan oceanic basin? Another important ambiguity is whether western Paleotethyan gulf (paleogeographically situated between Dinarides and Serbo-Macedonian Unit?) was closed in the Triassic or the early Alpine Triassic transition into the Neotethys was rather smooth?

Objectives

Findings

Conclusion