Mineralized, Scapolite-Rich Skarns From Cajón Grande And Cajón Del Medio Creeks, NW Neuquén, Argentina

FRANCHINI MARTA; LARRY MEINERT; ABEL ISIDORO SCHALAMUK

Mineral Deposits: Processes to Processing

Balkema

Lugar: Rotterdam; Año: 1999; p. 1043 - 1046

Recent exploration in NW Neuquén has discovered pyrrhotite-rich pyroxene-amphibole-biotite hornfels and zoned, fine-grained skarns with pyroxene (Hd7.5-79), scapolite (Me28-61) garnet (Ad7.5-98.5), minor wollastonite, Fe-rich biotite, and retrograde amphibole, chlorites, epidote, calcite, quartz and prehnite, with As-Bi-Sb-Ag anomalies. They are hosted by micritic limestone interbedded with siltstone in the contact with calc-alkaline, metaluminous, and reduced (mean Fe2O3/ Fe2O3+FeO = 0.39) diorite-gabbro sills and stocks, with high Al2O3 (17.1-20.9%), MgO (1.5 to 5.5%), Sc (10 to 20ppm), V (53 to 222) and Ni (20 to 35) and low Si (50.1-64.9%), Y (13.3 to 23.8) and Rb/Sr ratio (0.01 to 0.19), all attributes of world-class gold skarns