4: Transpressional tectonics, lower crust decoupling and intrusion of deep mafic sills: A model for the unusual metallogenesis of SW Iberia

The metallogenic characteristics of the two terranes are quite different. In the Ossa Morena Zone, juvenile magmatism played a major role as the source of metals, and controlled the styles of mineralization. In the South Portuguese Zone, magmas only acted as heat sources but seem to have had no major influence as sources of metals and fluids, which are dominated by crustal signatures. Most of the magmatic and tectonic features related to the Variscan subduction and collision seem to be masked by those resulting from transpressional deformation and deep mafic intrusion, which led to the development of a metallogenic belt with little resemblance to other accretionary magmatic arcs.