Estudio mineralógico del depósito de caolín María Eugenia, Tandilia, Argentina

Abstract

Clay deposits in Buenos Aires province are located in different stratigraphics units of the Sierras Septentrionales or the Tandilia system. The present contribution is focused in the geological and mineralogic knowledge of the kaolinitic clays from the Sierra del Volcán, Balcarce, which were formerly operated in the “María Eugenia”-mine. The application of modern techniques such as Reflectance Spectroscopy SD Field Spec ProTM, Scanning Electron Microscopy (SEM) and the use of XPowder software for interpretation of X-ray diffractions patterns, allowed recognize different sectors within the mineral deposit with varying degrees of argilization. The most outstanding (west) has identify the association kaolinite of high crystallinity + illite 2M1 along with the development of a dense texture of the crystals, indicate a hydrothermal origin for the kaolinite, has detected subordinately kaolinite variety of low crystallinity is associated with goethite and develops a less dense texture indicating a supergene origin. The presence of sulfides and quartz veinlets cross-cutting the Buenos Aires Complex rocks, recognize in west area, are evidence of fluid flow through this rocks, and could be the responsible for the argilic alteration developed on the rocks of basement.