Share this article By Ellsworth Dickson The Iberian Pyrite Belt is a vast geographical area that is one of the world’s great regions hosting metallic mineral deposits where over 2,000 million tonnes of ore has been extracted. The belt stretches along much of the south of the Iberian Peninsula, from Portugal and into Spain. It is about 250 km long and 30–50 km wide, running northwest to southeast from Alcácer do Sal, Portugal, to Seville, Spain. The Iberian Pyrite Belt was formed 350 million years ago in the Devonian Period, connected to active and hydrothermal volcanism that led to the formation of a volcanic-sedimentary complex. Volcanic activity in the region led to eight giant volcanogenic massive sulphide ore deposits (VMS) associated with polymetallic massive flanks of volcanic cones in the form of pyrite, chalcopyrite (copper), sphalerite (zinc), galena (lead) and cassiterite (tin). Over 250 deposits are known in the belt.