ESTUDIO HIDROGEOQUÍMICO E ISOTÓPICO DEL SISTEMA BARRANQUITAKNUTZEN. CÓRDOBA. ARGENTINA

GIULIANO ALBO, J.; BLARASIN, M.; PANARELLO, H.O.

Salta

Congreso; VII Congreso Argentino de Hidrogeología y V Seminario Hispano-Latinoamericano Sobre Temas Actuales de la Hidrología Subterránea. Calidad y Contaminación de Agua Subterránea; 2011

In this paper a hydrogeochemical and isotopic characterization of surface water andgroundwater of Barranquita-Knutzen basins is presented. Conventional geologicalhydrogeologicalmethodologies were used and environmental isotopes analysis (18O y 2H) were made. The unconfined aquifer is made up of Quaternary sediments of loessical type, interlayered with sand and gravels (paleochannels) in the piedmont sector. There is a control of lithological-geomorphological features in the chemical composition of water: surface water and groundwater of Barranquita upper basin and piedmont area is fresh, because of the high slopes, thin aquifer and coarse sediments, which produces high flow velocities and less saline enrichment. Conceptual and numerical models indicate that the dominant geochemical processes are dissolution-precipitation (carbonates), cation exchange (Ca2+/Na+), without dismiss hydrolysis of silicates. It was observed that surface water and groundwater have an isotopic depletion in an E-W direction that can be related to the rainfall recharge that has been affected by continental effect or fractionation at lower temperatures (rainfall in upper basin). On the other hand, surface water and groundwater samples of the Barranquita upper basin and piedmont area show an isotopic depletion forming a group above the regional meteoric line indicating the need to make a local one.