The Sebes Lotru terrane (SLT) is the largest basement unit of the South Carpathians and of the Dacia superterrane, and one of the largest basement terrains in Alpine Europe. It represents the metamorphosed basement of the Alpine Getic thrust sheet and is covered in places by Alpine unmetamorphosed rocks. Its relationships to most other basement units in the South Carpathians is tectonic and related to the assembly of a Mesozoic-aged fold and thrust belt; only its juxtaposition against greenschist facies rocks to the north and east in a small area the Cibin and Lotru Mts is documented to be Permian, possibly early Triassic. SLT was metamorphosed to amphibolite facies during the Variscan orogeny. Previous regional zircon (detrital and igneous) U-Pb studies have shown a continuous Ediacaran to – early Silurian magmatic arc, with some small amount of additional inherited ages at 1 Ga and older than 2 Ga. A major 460-470 Ma zircon age peak dwarfs all other ages in the zircon archive and reflects a flare-up event at that time. However useful, these ages are insufficient in unraveling the full origin of these rocks without a petrologic context and very few constraints on timing of their metamorphism.
Mihai N. Ducea (Tue,) studied this question.