Revista de la Asociación Geológica Argentina
versión impresa ISSN 0004-4822
LEAL, P.R.. Fluid inclusions and stable isotopes in non-ore minerals of the manganese ore deposits in the north of the Córdoba province. Rev. Asoc. Geol. Argent. [online]. 2002, vol.57, n.3, pp. 251-259. ISSN 0004-4822.
In this paper the non-ore minerals of the southern sector of this deposit are studied. Microthermometric analysis on calcite, barite and fluorite show fluid salinities of 2.7 and 4% wt eq. NaCl, and temperatures below 100°C. Isotopes of 13C, 18O and 34S allow to determine a meteoric source for the fluids associated to their precipitation. The d13C values obtained in calcite are considered the result of a fluid in equilibrium with atmospheric CO2 plus the addition of carbon due to dissolution of organic compounds. On the other hand, the d34S values of barites can be explained by another fluid with H2S contents resulting from the dissolution of sulfides from the wall-rock. Finally, the presence of two different fluids is postulated here. An upward fluid was responsible for the barite precipitation where the H2S was oxidized to SO4=. This fluid could form fluorite and silica varieties as its temperature decreases. The existence of a downward fluid explains calcite generation as the descending fluid is heated.
Palabras clave : Fluid inclusion; Stable Isotopes; Manganese; Sierras Pampeanas.