THE MAPPING AND ANALYSIS OF AU-BEARING QUARTZ VEINS IN GANARIN, ECUADOR

Southern Ecuador's Azuay province contains a prospective Au-Ag mine site called Ganarin. During the summer of 2005, a comprehensive geologic map was created of the 9km2 area. This map contains locations of quartz and calcite veins, faults and surficial contacts. Using a Garmin GPS and Brunton Compass, the location and orientation of quartz and calcite veins were recorded. Through this data, a cross sectional map was created to determine where these veins intersect at depth. We discovered areas where between two and five veins intersected, which could possibly contain Bonanza style gold deposits. Samples of quartz veins and their surrounding altered andesite host were collected for further inspection. Using an X-Ray diffractometer, alteration silicates within the andesite were analyzed. These alteration minerals were identified to be predominantly sericite, muscovite, adularia, and alkali feldspars such as sanidine. Quartz vein samples were then examined using an SEM with EDS. The samples contained cross-cutting veins of sulfides suggesting multiple pyrite events. Other sulfides found within the samples were chalcopyrite, sphalerite, and small concentrations of Sn, Ni, Cu, and P. Au and Ag were also present, typically occurring together as isolated blebs within the quartz matrix. The presence of pyrite, Au and Ag concentrations within quartz veins, as well as the occurrence of sericite, adularia and quartz replaced calcite in the field, confirm our assumptions that this area represents a low sulphidation environment with epithermal gold and silver deposits.