La paragénesis Cu-Au-Bi (Ag-Pb) en el cordón de los Galeses, Cordillera Patagónica (43º 30' L.S.)

WIECHOWSKY A-M; AMETRANO SJ; HALLER MJ

La Plata

Congreso; III Reunión de Mineralogía y Metalogenia y III Jornadas de Mineralogía y Metalogénesis de Rocas Máficas y Ultramáficas; 1996

The Cu-Au-Bi (Ag.Pb) paragenesis of a quartz vein is described. This and other veins occur within Jurassic-cretareous volcano-sedimentary sequence intruded by late cretaceous granitoids in the Patagonian Andes. The mineral assemblage is composed by: chalcopyrite, pyrite, gold and Bi-sulphosalts. This paper is mainly devoted to the chemical determination of the sulphosalts-  All of them have similar optical properties and could be differentiated by microprobe analysis: It have been foundtwo members of the aikinite-bismuthinite serie: krupkaite (18.8 Pb; 0.025 Ag; 6.68 Cu; 55.32 Bi, 18.20 S; wt %) and a phase belonging to the gladite-pekoite range. Three others belong to the cuprobismuthite serie: Ag rich paderaite ? (7.15 Pb; 4.05 Cu; 13.14 Ag; 57.15 Bi; 18.10 S; wt %); Ag rich hodrushite ? )0.56 Pb; 5.85 Cu, 16.38 Ag; 58.90 Bi; 18.30 S; wt %) and cuprobismuthite (13.76 Cu; 2.01 Ag; 63.76 Bi; 19.75 S; wt %).