Geoquimica de los procesos de alteracion hidrotermal en la mineralizacion de Sb de Mari Rosa (Zona Centro Iberica)

Abstract

The Central Iberian Zone of the Hesperian Massif hosts a series of late Hercynian vein-type Sb deposits. One of them is the Mari Rosa mineralization. The mineralization is characterized by a complex paragenesis comprising arsenopyrite-(pyrite), stibnite-gold and pyrite-pyrrhotite-galena-sphalerite-chalcopyrite-tetrahedrite- boulangerite-stibnite. Hydrothermal alteration consists of a mild sericitization, chlorization and carbonatization of the metasedimentary rocks around the veins. A remarkable increase in the ratio K2O/Na2O and a decrease in the ratio SiO2/volatiles can be used as clear-cut indicators of the extension and magnitude of the hydrothermal alteration. Other changes include increases in Sb, Mo and Au around the veins. The isotopic signature of stibnite and pyrite is close to the typical values of magmatic sulphur. This, together with the high correlations between Sb and Mo strongly suggest a genetic relationship between the Mari Rosa mineralization and the intrusion of the Alburquerque batholith. -from English summary