The continuation of the Internal Dinaridic units in the area between the Periadriatic Lineament and the Southern Alps in Slovenia

Abstract

Three Internal Dinaridic tectonostratigraphic units are included in the PANCARDI domain; 1) the Bosnian Flysch, composed of the Liassic to Berriasian Vranduk Subgroup and the Albian to Maastrichtian Ugar Subgroup, originating on the passive Tethyan margin, 2) the Dinaride Ophiolite Zone, made up of the Radiolarite Formation, ophiolite included within the Jurassic olistostrome mélange, and a Cretaceous overstep sequence, partly with Urgon-type(?) signatures, and 3) the Sava-Vardar Zone, composed of Cretaceous-Early Paleogene flysch, locally with subduction-related basalt-rhyolites, a Paleogene, very low to medium-grade metamorphic sequence originating from the Cretaceous-Paleogene flysch, Paleogene tectonized ophiolite mélange, Eocene syncollisional granitoid occurrences and Oligocene postcollisional ones, accompanied by coeval shoshonite and andesite. All these formations occur as allochthonous blocks within two segments of the southern and western Pannonian Basin. 1) In the adjoining Tisia-Dinarides segment, the Sava-Vardar Zone lithologies occur both at the surface and in the subsurface of the Pannonian Basin, as the result of postorogenic Dinarides-Tisia interaction. Those located in the basement were uplifted during the Oligocene wrench faulting, which controlled the initial development of the Sava and Drava depressions. Those found at the surface were emplaced during the Pliocene phase of strike-slip faulting. 2) More common are Internal Dinaridic fragments sandwiched within the Alps-Dinarides-Tisia (e.g. Carpathians) triple junction area, e.g. the Zagorje-Bükk-Meliata Zone. In its southwestern Sava Subzone occur fragments of the Bosnian Flysch Zone and Sava-Vardar Zone, represented by a Paleogene tectonized ophiolite mélange, Cretaceous-Paleogene flysch and postcollisional andesite-shoshonite. The northeastern Bükk-Meliata Subzone is composed of a Jurassic ophiolite mélange correlative to the Dinaride Ophiolite Zone, which in its Slovakian part is thrust by Triassic, mainly carbonate formations. The accompanying Mónosbél Flysch can be correlated with the Vranduk Subgroup of the Bosnian Flysch. The displacement of the Internal Dinaridic formations can only partly be explained by Tertiary escape (extrusion) tectonics.