The geology of Romania is dominated by the Carpathian Orogen of Alpine age, and its foreland which includes several platforms and also the North Dobrogea orogen of Cimmerian age.
The Moldavian platform, part of the East European platform, consists of Lower Proterozoic midgrade metamorphic basement (gneisses intruded by gaggros, anorthosites and granites) and the sedimentary cover (several sedimenatry cycles: vendian-Cambrian, Ordovician-Silurian, Devonian, Upper Jurassic-Cretaceous, Eocene and Oligocene).
The Scythian platform is a possible mobile margin of the East European platform. The folded basement of Caledonian-Hercynian age involves old metamorphic rocks and Paleozoic ankimetamorphic and sedimentary formations. The sedimentary cover includes Upper Devonian, Carboniferous, Permian, Triassic and Jurassic rocks. Youger (Neogene) sedimentary formations are common with those of the Carpathian foreland.
The Moesian platform consists of Precambrian metamorphic rocks (midgrade and highgrade metamorphites of Middle Proterozoic age, and green schists of Vendian-Lower Cambrian age) representing its basement. The sedimentary cover developed in Cambrian-Carboniferous, Permo/Triassic-Cretaceous cycles.
The North Dobrogea orogen has a nappe structure: Macin, Tulcea (involving continental crust: Precambrian-Lower Paleozoic metamorphites and granites, and sedimentary formations of Middle Paleozoic - Jurassic age) and Niculitel (mafic complex: basalts and carbonatites of Spathian-carnian age).
The Carpathian Orogen
The Eastern Carpathians consist of numerous tectonic units, overthrusted successively from west to east. They result from a long-term Alpine evolution, with main development Dacidic (Middle and Upper Cretaceous) and Moldavic (Miocene). The flysch formations start from Early Cretaceous and are very well developed. They represent the main lithological component, sometimes transgressively covered by Vraconian-Cenomanian and Upper Cretaceous-Paleogene detritic, post-tectogenetic formations. The Neogene volcanic chain was developed in Sarmation-Early Pliocene and Late Pliocene-Quaternary. The age migrated from northwest to southeast, from 10 to 0 million years, relating to overall tectonic development. The calc-alkaline volcanism progress from Western to Eastern Carpathians (18 Ma in W to 0 Ma in East). The structures show a similar age progression from W to E. The composition was changed through time from rhiolites and dacides, to andesites and basaltes.
The Southern Carpathians consists of four main tectonic units:
Getic Nappe - basement with some granitic bodies, mid- to high metamorphica grade rocks of Carboniferous age, covered by molasse formation.
The Supra-Getic Nappe - has a lower grade metamorphic basement and a Mesozoic calacareous-sedimentary cover;
The Severin Nappe - consists of Tithonic-Cretaceous formations, associated with ophiolitic complexes,
The Danubian Autochtonous - mid grade metamorphic basement often intruded by granitoides and molasse deposists of Permian to Carboniferous age, transgressively covered by Mesozoic sediments .
The Carpathian Foredeep is filled with Upper Pliocene - Lower Pleistocene molasse from the erosion of the Carpathians. It covers most of the external units of both the Eastern and Southern Carpathians, and part of the surrounding platforms.
The Apuseni Mountains consists of two distinct areas, Northwest Apuseni and Southeast Apuseni (Metaliferous Mountains), both intruded by banaties of volcanic facies, generating rhiolites taphroid from Vladeasa and then penetrated by eruptions, so generating the Neogene volcanism for the Metaliferous mountains.
The Transylvanian depression is a molasse depression of Neogene age, developed above the Carpathian deformed units and their post-tectogenetic cover. The Upper Cretaceous - Paleogene, Miocene, and Pliocene sediments with a salt layer in the Badenian and volcanic tuffs, developed at different levels.
The Pannonian basin is a Neogene depression, extended above the Apuseni Mts. units, with Middle - Upper Miocene and Pliocene formations and Lower Badenian evaporite level.
|Dr. V. Mocanu|
|Fakulta geologie a geofyziky|