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Tectonostratigraphic terranes in the Circum-Pannonian region (pre-Neogene basement of the Pannonian Basin and its Alpine-Carpathian-Dinaridic frame): a school example of exotic terranes

Tectonostratigraphic terrane maps of the Circum-Pannonian region showing paleoenvironments from the Devonian to Jurassic were published by the Hungarian Geological Institute in 2004 on the occasion of the Geological Word Congress held in Florence. The explanatory book of these maps in form of a monography is going to be published by the Geological Institute of the Slovak Academy of Science on the occasion of the present congress of the Carpatho-Balkan Geological Association. We shortly present the essential principles of the maps and related monography chapters, and implications for the terranology of the area concerned. Obducted remnants and suture zone(s) of the NW part of the Mesozoic Neotethys Ocean can be found in the internal zones of the Hellenides–Dinarides and then as small, dispersed blocks in the Circum-Pannonian region more to the North. The European (Carpatho-Balkanide) margin of this ocean was formed upon the Variscan Moldanubian Zone and Mediterranean Crystalline Zone, respectively. On the other hand, its Adriatic margin was formed upon the eastern part of the Variscan Carnic–Dinaridic microplate. Its rifting began in the early part of the Middle Triassic, whereas in the Hellenides already in the late Early Triassic. Moreover, the Main Vardar Zone is supposed to have existed already in the Paleozoic, thus representing an inherited Paleotethyan domain. This pattern of deformed continental margin zones and remnants of one/or two oceanic zone(s) inbetween them is preserved until the southern margin of the Pannonian Basin, until the Bosnian–Serbian sector. Further to N, in the basement of the Pannonian Basin this pattern is completely changed due to intervening of the large Tisia Megaterrane. Small displaced Neotethyan remnants can be followed from the NW Dinarides (Medvednica, Kalnik Mts. in NW Croatia) through the Mid-Hungarian Zone up to the Bükk-Darnó area in NE Hungary and Jaklovce Subunit of Meliaticum in SE Slovakia (Zagorje-Bükk-Gemer Composite Terrane). Another branch of these remnants can be followed E of the Tisia Megaterrane to the Transylvanides of Romania. On the other hand, the northern part (Mecsek Zone) of the Tisia Megaterrane was formed on the Variscan Moldanubian Zone, whereas its southern part on more southern Variscan crystalline—granitoid complexes comparable with those of the Eastern Alps and West Carpathians (Mediteranean Crystalline Zone). It was part of Europe until early Middle Jurassic and became separated from there in the Bathonian due to the beginning of Penninic rifting. The present terrane pattern of the Pannonian basement was then formed later due to late Mesozoic and early Tertiary rotational and strike slip movements. As a result of them, units/terranes of opposite origin became juxtaposed in the central part of the Pannonian basement, thus this area can be considered as a school example of exotic teranes. On the other hand, small Neotethyan remnants (Meliatic, Transylvanide), which became separated from the main Neotethyan trunk already in the Late Jurassic to Early Cretaceous times and became involved in Middle to Late Cretaceous nappe stackings of the Carpathians, represent typical disrupted terranes.

Circum-Pannonian region; rifting

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