Resumo

LEAL, Pablo Rodrigo  e  GONZALEZ, María Paz. Mineralogy and fluid inclusion of LaBaritina: theuppermost sector of the manganese mineralization of sierra de Ambargasta, province of Córdoba. Rev. Asoc. Geol. Argent. [online]. 2009, vol.64, n.4, pp.672-684. ISSN 0004-4822.

In this paper the mineralogy and fluidinclusion of the upper sector of an epithermal manganese deposit are described.The study area comprises the central sector of a bigger mineralised zone wherenon-ore mineral are the most common ones and are composed of barite, calciteand opal with fewer amounts of chalcedony, quartz and manganese oxides. Theirtextures and their assemblages allow us to determine several events ofprecipitation. The open spaces between barite crystals were filled by calciteand opal which are commoner species toward the end of the mineralizationprocess. Chalcedony and quartz only occur inside a few small cavities. Fluidinclusions were studied in barite, calcite and quartz samples. They arecomposed of H₂O, NaCl and fewer amounts of CaCl₂ and MgCl₂.Calcite and barite samples have an average salinity of about 4.18 %wt NaCleq.,meanwhile quartz evidences salinities around 5.26%wt NaCleq. Homogenizationtemperatures are also different for each species: quartz shows an averagetemperature of about 148°C, meanwhile barite and calcite seem to be a littlehigher (184º and 171°C respectively). All the data compiled in this papersuggest that this district represents one of the uppermost sectors of the oredeposit. The high amount of non-ore minerals evidences that this area, incontrast with the others ones, was especially active during the end of themineralization process.

Palavras-chave : Barite; Manganese; Ambargasta; Córdoba.

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