Two well-developed styles of mineralization occur in the Nevados del Famatina mining district, Famatina ranges, La Rioja province, Argentina. Porphyry molybdenum- copper-gold mineralization and high level acid sulphate alteration/mineralization (Nevados del Famatina) are related to intrusion of the Pliocene Mogote rhyodacite porphyry complex. High sulphidation epithermal mineralization (La Mejicana) is developed peripheral to the Nevados del Famatina deposit. Both are hosted mainly by the Ordovician Negro Peinado metapelites._x000D_
At Nevados del Famatina, five mineralized fracture events have been identified and correlated with four distinct alteration assemblages. Stage I (barren quartz) and stage II (molybdenitesphaleritepyrite) mineralization are associated with a K-silicate alteration assemblage of K- feldspar+biotite+quartz+magneti teilmeniteanhydrite._x000D_
Stage III (bornite+pyrite+sphalerite+molybdenite chalcopyriteidaite) and stage IV (chalcopyrite+pyrite +sphalerite+goldtennantite-tetrahedrite) mineralization are related to a quartz-sericite assemblage of quartz +phengite+illite+pyrite+rutile. Stage V mineralization is divided into two substages. Stage Va (chalcopyrite +pyrite+sphalerite tennantite-tetrahedrite_x000D_
tellurides_x000D_
gold enargitefamatinitestibnitemolybdenite) is related to a sericite-clay assemblage of quartz+illite+kaolinite montmorillonitealunite. Alunite-kaolinite alteration (alunite+pyrophyllite+kaolinite+ aluminum - phosphate - sulphate minerals illitefluoritecorundumanhydrite) occurs in the upper part of Nevados del Famatina associated with the later stage Vb (quartz+famatinite +chalcopyrite+covellite + chalcocite_x000D_
marcasite_x000D_
enargite_x000D_
luzonitesphaleritemelnikovite) mineralization.