PALAEOZOIC ROCK ASSEMBLAGES INCORPORATED IN THE SOUTH CARPATHIAN ALPINE THRUST BELT (ROMANIA AND SERBIA): A REVIEW

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Abstract

The Alpine fold and thrust belt of the South Carpathians overrides the Moesian platform to southeast and the Serbo-Macedonian and Vardar ophiolitic palaeosuture to northwest. The pre-Triassic basement of the South Carpathians is preserved in the Getic/Supragetic and Upper Danubian/Lower Danubian basement/cover nappe systems and is represented by: a, Late Carboniferous-Permian sedimentary deposits and related magmatites; b, pre-Westphalian metamorphic-magmatic suites of Palaeozoic and Neoproterozoic age. Palaeozoic sedimentary and volcano-sedimentary lithological assemblages, palaeontologically dated, are of ?Cambrian-Ordovician-Silurian and Late Devonian-Early Carboniferous ages. The Early Palaeozoic rock-sequences preserved in the Danubian basement are discontinuous covers of the Pan-African terranes or rift-related, allochtonous low-grade successions associated to an inverted ophiolitic-sedimentary-tectonic palaeosuture marking a plate/microplate boundary. The Early Palaeozoic successions in the Getic-Supragetic basement are mainly allochtonous volcano-sedimentary rocks associated with basic and bimodal magmatic rocks marking a back-arc basin and an intracontinental rift, separating Neoproterozoic ± Early Palaeozoic gneissic terranes. Unconformable Late Devonian-Early Carboniferous successions consist of continental-shallow marine, clastic and/or carbonate-dolomite piles (Danubian and westernmost Supragetic) but some volcano-sedimentary grading to coarse-grained clastic successions are also present (Getic basement). Late Carboniferous-Permian, clastic, sometimes coal bearing, continental deposits crop out in both Getic-Supragetic and Danubian basements while volcano-sedimentary successions, associated with acid or bimodal volcanic rocks, crop out mainly in the Danubian units. In contrast with the unmetamorphosed Palaeozoic cover of the Moesian Platform, the Variscan regional prograde metamorphism of the Carpathian Palaeozoic rock sequences ranges from anchizone to greenschist and epidote-amphibolite facies. Early Palaeozoic deformation and metamorphic evolution of the Danubian basement is different in the external and internal domains, suggesting different geotectonic environments before the deposition of ?Late Ordovician-early Silurian formations, and, possible Avalonian-Moravian affinities. Polystage Variscan tectono-metamorphic events are documented for the Getic-Supragetic basement and show Armorican-Bohemian affinities. Both, Danubian and Getic-Supragetic Domains inherited Gondwana derived gneissic-granitic terranes whose Palaeozoic evolution is diversified. The Pan-African gneissic-granitic suites of the External Danubian Domain are slightly involved in Variscan deformation and metamorphism. Different by this, the Neoproterozoic basement of the internal Danubian and Getic-Supragetic Domains were reactivated and rejuvenated in Palaeozoic time, the rifting/dismembering of northern Gondwana being followed by convergence to collision in the Variscan cycle.  

Om dit artikel te citeren:

Over : Viorica IANCU

Over : Tudor BERZA

Over : Antoneta SEGHEDI

Over : Marcel Marunţiu