Geodynamic evolution of the central Dinarides

The central part of the Dinarides, unlike the northwestern and southeastern Dinarides, shows a consistent pattern in the distribution of the large tec tonostratigraphic units. From southwest (Apulia) to northeast, the followin g five main units originating in different parts of the Mesozoic Tethys, ca n be distinguished: (I) Adriatic-Dinaridic carbonate platform formations; ( 2) carbonate-elastic units ('flysch bosniaque') of the passive continental margin; (3) ophiolite-bearing formations of the Dinaridic Ophiolite Zone, a lso containing radiolarites, greywackes and shales, including melange forma tions, and overstepped Late Jurassic to Cretaceous cover sequences; (4) act ive continental margin units represented by Upper Cretaceous-Palaeogene tre nch sediments with blueschists, tectonized ophiolite melange, Alpine medium -pressure metamorphic rocks originated from Upper Cretaceous-Palaeogene sed iments, and Alpine synkinematic granitoids; (5) a nappe consisting of alloc hthonous Palaeozoic-Triassic formations which is thrust onto the ophiolites and genetically related sedimentary formations. The frontal parts of this nappe directly overlie the northeastern margin of the Adriatic-Dinaridic ca rbonate platform, i.e, the External Dinarides. The evolution of the Central Dinarides was controlled by a sequence of tect onic events which took place within the Alpine cycle: (1) Rifting processes lasting some 40-50 Ma which started in the Late Permian and ended in the N orian, (2) Opening of the oceanic Dinaridic Tethys commenced in the Late Tr iassic and persisted for some 70-80 Ma until the end of the Jurassic, (3) S ubduction processes and emplacement of ophiolites started in Late Jurassic- Early Cretaceous times; during the closing phase of the 'Dinaridic Ocean' ( or Dinaridic Tethys) the Palaeozoic-Triassic nappe was emplaced on the ophi olites. The thrusting was accompanied by Alpine metamorphism (120-100 Ma). (4) The main Alpine deformational event and medium-pressure metamorphism wi th synkinematic granite plutonism took place in Late Eocene-Early Oligocene times when the ophiolite and Palaeozoic-Triassic nappes were emplaced on t he Adriatic-Dinaridic carbonate platform which, at the same time, was defor med resulting in the development of the External Dinarides fold-and-thrust belt. (C) 1998 Elsevier Science B.V. All rights reserved.