Copper-ore grade hydrothermal mineralization discovered in a seamount in the Tyrrhenian Sea (Mediterranean): Is the mineralization related to porphyry-coppers or to base metal lodes?

Abstract

A luzonite and tennantite-tetrahedrite-bearing massive sulfide mineralization was discovered when sampling the crater of the Palinuro seamount, located within a probable island-arc or marginal basin tectonic setting. The mineralization is made up of indurated sulfide crusts interpreted to have been deposited by a seawater/sediment interface and mixed with ooze of organic and volcanic origin. A preliminary investigation of the economic minerals showed besides luzonite and tennantite-tetrahedrite, native (rare) copper?, all associated with pyrite predominantly and baryte. Native silver, bismuthinite and stibnite were also found. A dust-like white precipitate was observed by submersible close to the mineralized zone but no structures or edifices resembling black smokers have yet been identified. Massive pyrite deposits associated with such uncommon mineral assemblages are found in the high level volcanic parts of porphyry copper systems, or associated with base metal lodes. The massive sulfide discovery is suggested to have a volcanogenic exhalative origin and a genetic relationship with porphyry coppers or base metal sulfide lodes.