Seafloor Volcanism and Polymetallic Sulfide Deposits in Ancient Active Margins: The Case of the Iberian Pyrite Belt

Abstract

Massive polymetallic sulfide deposits occur throughout the Iberian Pyrite Belt. The mineralization is related to submarine felsic volcanism that took place during the Upper Devonian-Lower Carboniferous evolution of the South Portuguese Zone. The geotectonic setting of the IPB is reexamined taking into account the results from active margin drilling under Deep Sea Drilling Program/IPOD. Changes of the mode of subduction from M-type to C-type, appears to be a reasonable model for the geological conditions prevailing at the IPB. It is suggested that the link between field geology and geochemical studies carried in ancient subduction complexes coupled with the studies of modern analogs, allows a better understanding of convergent margins and their ore deposits.