Changing Carboniferous Arc Magmatism in the Ossa-Morena Zone (Southwest Iberia): Implications for the Variscan Belt

Carboniferous magmatism in southwestern Iberia was continuously active for more than 60 m.y. during the development of Appalachian-Variscan belt North America, Africa and Western-Central Europe. This collisional orogen that records closure Rheic Ocean is essential to understanding late Paleozoic amalgamation Pangea supercontinent. However, oblique convergence between Laurussia Gondwana lasted from Devonian likely complex. Recently, a new tectonic model has regarded Variscan as site coeval accretionary orogenic processes. Early plutonic rocks southwest indicate arc Gondwana. The Ossa-Morena Zone (OMZ) acted upper plate relation geometry Paleotethys subduction. accretionary-extensional margin progressively involved phase Late Carboniferous. Together, Évora Massif Beja Igneous Complex include three successive stages bimodal magmatism, with chemical composition indicative long-lived subduction process lasting Tournaisian Moscovian OMZ. earliest stage includes Torrão gabbro-dioritic Layered Gabbroic Sequence. We present geochemical Nd isotopic U-Pb geochronological data magmatic Main (Visean-Serpukhovian) Latest (Bashkirian-Moscovian) magmatism. Visean Toca da Moura trachyandesite rhyolites Bashkirian Baleizão porphyries Alcáçovas quartz diorite share enriched, continental-crust like characteristics, indicated by major trace elements, mainly suggesting addition calc-alkaline magma extracted various mantle sources subduction-related setting (i.e., subduction). New zircon geochronology have allowed us establish crystallization age 317 ± 3 Ma (Bashkirian) confirms temporal link porphyry. Positive ?Nd(t) values igneous gneiss dome production juvenile crust, whereas negative also suggest different grades evolution involving crustal contamination. continental crust OMZ most associated an Gondwana, materials