Tectonic evolution of the Vršac Mts. (NE Serbia): Inferences from field kinematic and microstructural investigations

Abstract

The Vršac Mts. in NE Serbia represent the key area to investigate structural relations between the Northern Serbo-Macedonian Subunit and Supragetic Unit of the Dacia Mega-Unit. The geodynamic events during the Variscan orogeny in the Late Paleozoic colligated the two units and led to their metamorphic differentiation. The Late Cretaceous extension exhumed the medium-grade Serbo-Macedonian metamorphic rocks and structurally juxtaposed them against the low-grade metamorphosed basement of the Supragetic Unit along an E-dipping shear zone, which outcrops in the crystalline basement of the Vršac Mts. The subsequent Oligocene–Miocene extension, which led to the formation of the Pannonian Basin, overprinted the effects of earlier tectonic phases to a large extent. Hence, large segments of the Northern Serbo-Macedonian Subunit and the Supragetic Unit, including their contact, were buried beneath the Neogene deposits of the southern part of Pannonian Basin. The tectonic uplift of the Vršac Mts. occurred in middle to late Miocene times along the SW-dipping normal faults that controlled deposition in the adjacent Zagajica Depression. The Miocene extension, triggered by the retreat of Carpathian slab, exhumed the crystalline basement of the mountains, and exposed the Late Cretaceous Serbo-Macedonian/Supragetic extensional contact.