Neoproterozoic-paleozoic evolution of the Drina formation (Drina-Ivanjica entity)

Abstract

This paper addresses a Drina-Ivanjica basement member, Drina Formation, characterized by ŕ controversial Neoproterozoic to Carboniferous age. The Drina Formation is also informally referred to as the “Lower Drina Formation” and the “Upper Drina Formation” including the Golija Formation as a conditional analog unit of the latter. A review of the biostratigraphic, sedimentary and paleogeographic constraints identified Drina Formation (Inner Dinarides) as a migrated crustal segment derived from a marginal section of northern Gondwana, being, however, of Neoproterozoic-Early Paleozoic age. The presence of arenites, pelites, conglomerates, scarce limestones, basic (sub)volcanics and tuffs of the volcano-sedimentary Drina Formation metamorphosed up to greenschist and locally up to amphibolite facies, coupled with the absence of felsic volcanism implies a passive margin setting. Considering the age, such environment was probably associated with the perplexed Lower Paleozoic Avalonian-Cadomian arc, situated along the former north Gondwanan active margin. More precisely, the Drina Formation originated from a depositional junction between the Gondwana sediment supplier (Sahara metacraton) and Cadomian arc. A comparison with the regional Early Paleozoic succession of the “Kučaj Unit” (eastern Serbia) yields the absence of typical anchimetamorphic Silurian to Lower Devonian deep-marine fossil-bearing succession. The volcano-sedimentary passive margin system of Drina Formation is overlain by a late Variscan convergencerelated voluminous clastic sequence allocated as the Golija Formation.

Keywords

• Drina-Ivanjica
• Neoproterozoic-Paleozoic
• Drina Formation
• Avalonian-Cadomian arc