Mineralogía y paragénesis de "La Estancia", un depósito epitermal de la Sierra de San Luis

MÁRQUEZ-ZAVALÍA M. F. Y GALLISKI M. A.

Revista de la Asociación Geológica Argentina

Instituto Salesiano de Artes Gráficas

Lugar: Buenos Aires; Año: 1994 vol. 49 p. 39 - 47

0004-4822

ABSTRACT. Mineralogy and paragenesis afta Estancia'', an epithermal deposit in the San Luis range. La Estancia mine (32°47' S and 66° 02' W) is an epithermal deposit associated with Caenozoic andesitic-latitic volcanism of the San Luis ranga. Thehostrocks, which are sericitized and silicified, are gneisses, quartzites, milonites and blastomilonites ofthe czystalline basement.The deposit is controlled by a 1500 m long fracture, with N75°W strike and 85°S dip, that is more highly mineralizad in itseastemparí. The vein type mineralization, with a quartz gangue, la representad by Au and Ag and Fe, Zn and Pb subidas. The veinminarais were studied by optical methods, X-ray diffraction and SEM with EDAX. It was possible to characterize 90 mineral.The hypogene species include gold, electrum, albur, galena, sphalerite, pyrite, marcasita, pyrrhatite, arsenopyrite, chalcopyrite,pyrargyrite, wolframite and graphite. The paragenetic interpretation suggests tour mineralization stages separated by periodoof fra.cturing . Both the paragenesis and the prevailing alteration are similar to those of low sulfidation type epithermal deposita.The occurrence of this epithermal type is algo supported by the shallow volcanic setting that includes the presence of aneighboring diatreme.