The Quebrada del Diablo Lower West Au deposit (Gualcamayo mining district, Argentina): A Carlin-type mineralization?

摘要

The Gualcamayo Mining District (GMD), located in the eastern margin of the Argentini an Precordillera includes three Au deposits: Amelia-Ines, Magdalena, Quebrada del Diablo Main, and QDD Lower West. The district has reserves of 491,000 oz. and resources of 2.3 million oz of Au.The metallogenetic analysis of these Au deposits based on previous work and new micro-geochemistry (LA-ICP-MS), isotopic (C-O-S-Pb) and fluid inclusions studies revealed that they are genetically linked and share many characteristics with Carlin-type deposits, including the lithology of host rocks, structural control, geo-chemical signatures, ore paragenesis, and dissolution and decarbonization processes. However, they also display some noticeable differences. The sulfur isotopic composition supports a genetic link between these gold deposits and the precursor magmatism of the porphyry-type mineralization of the area. Besides, the fluids responsible for the Au mineralization proved to be neutral to slightly alkaline and Au-saturated. The link with the magmatism along with the character of the mineralizing fluids and the presence of significant base metal sulfides allowed classifying the GMD deposits as "distal disseminated gold deposits" that occur on the distal edges of magmatic-hydrothermal systems.