This paper addresses a Drina-Ivanjica basement member, Drina Formation,
characterized by ? 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 ?Kucaj 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.
Crustal thickening in an active margin setting (Philippines): The whys and the hows
