engleski

Geotectonic position of the Pre-Alpine tectonostratigraphic units of the Internal Dinarides.

Disconnected allochtohonous pre-Alpine fragments, covering surfaces up to 4000 km2 each, disturbe the consistent zoned pattern in the spatial distribution of the predominant Alpine tectonostratigraphic units of the Internal Dinarides. The pre-Alpine formations, which originated during the Proterozoic, Cambrian-Ordovician and, Silurian to Middle Permian, are thrust over the Internal Dinaridic Alpine tectonostratigraphic units and the associated Triassic formations and included into three thrust systems. 1) The Pannonian-Golija-Macedonia out-of -sequance thrust, which is composed of Greenwilian, "Caledonian", Variscan and post-Variscan formations, continues northwestward into the Alps and southeastward into the Hellenides. 2) The Durmitor out-of sequence thrust, which is largely composed of Variscan and post Variscan formation stretches throu the southeastern Internal Dinarides and the northwestern Hellenides in Albania. 3) The Raduša Nappe(?), which has ambigous position, stretches into the middle and NW Dinarides. Its frontal parts were transformed into strike-slip Voljevac fault vduring the Tertiary wrench-faulting. For the geodynamic considereation are omprotant the facts as follows. If the basic mechanisms of plate tectonic dowork, then the pre-Alpine tectonostratigraphic units could not theoretically represent the basement of the evolving Alpine Tethys (i). The pre-Alpine disconected pre-Alpine complexes were emplaced immediately after Late Jurassic obduction of oceanic crust as indicated by common occurenc of tectonic windows composed of opiolite formrations within the Golija and Durmitor out-of sequence thrusts (ii). Fragmets both of ophilites and rocks of pre-Alpine formations are redeposited into transgressive Cretaceous Pogari Formation (iii). Many pre-Alpine fossiliferous formations, disregarding to which orogenic cycle they belong, were affected by Early Cretaceous greenschist facies overpring metamorphism (300-450oC and 3-5 kbar) which was probably related to Late Jrassic/Early Cretaceous global plate reorganization (iv).

Internal Dinarides; pre-Alpine formations; thrusts; out-of sequence

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