Favorability mapping of hydrotermal vein-type lead deposits: a case study in Ribeira Valley, Brazil

Abstract

The region of the Ribeira Valley is known for its metallic sulphide deposits (lead, zinc, copper, silver and gold), being the major lead producer of the Brazil in the 1950s. Since then, it has become the target of several geological studies from which two models of lead and zinc mineralization known as Perau and Panelas models were proposed. This study is particularly interested in the Panelas model, which is characterized by its vein morphology, association with carbonate rocks and structural control. Based on literature, this paper proposes to verify the applicability of the hierarchical analysis process (AHP) as auxiliary of the geographic information system (GIS) in the favorability mapping of hydrothermal veins-type Pb deposits which fit in the Panelas model. The study area is the western region of the Ribeira Valley, located in the southern portion of the São Paulo State, Brazil. In order to perform this work, four parameters were used: geological structure, stratigraphy, lithology and geochemistry. The result obtained highlights areas corresponding to Mina de Furnas, Bairro da Serra and Água Clara Formations as highly favorable areas to lead mineralization according this model. In addition, it shows the negative association of these geological formations with potassium concentration.