Tectonic setting and isotopic sources (Sm–Nd) of the SW Iberian Autochthon (Variscan Orogen)

Metasedimentary rock successions in Sierra Albarrana Group (SW Iberia Autochthonous Domain) were deposited during the Early Paleozoic influenced by evolution of a peri-Gondwanan active margin. Their geochemical composition indicates dominant contributions from felsic igneous sources and an upper continental crust provenance. The high mineralogical maturity, together with negative ?Nd(530), ranging ? 11.3 to 4.5, old Nd model ages (TDM: 1388–1897 Ma) imply reworked materials source areas limited juvenile contribution for siliciclastic sedimentary rocks Albarrana. Both, isotope features caused progressive denudation bearing isotopic imprint basement exposed along Gondwanan paleobasin SW Autochthon probably occupied outboard position across margin Ediacaran–Cambrian times. In convergent scenario, interaction between trench external part continent generated tectonic uplift, giving way exposure formed earlier stages Cadomian Orogeny erosion. Sediment redistribution through times supplied recycled detrital materials, which likely filled retro-arc basin after switch extensional compressional regime plate Orogen that is recorded throughout domain Iberia. A subsequent stage led widening its marginal basins, thus bringing onset passive Cambro–Ordovician onwards. overlap those Cambrian series southernmost Central Iberian Zone, are considered indication paleogeographic closeness all these sequences times, occupying eastern positions closer Tuareg Shield Sahara Metacraton sections