Mecanismos de recarga y salinización en las cuencas de los ríos Mendoza y Tunuyán, Mendoza, República Argentina, evidenciados por isótopos ambientales

PANARELLO, HECTOR; DAPEÑA, CRISTINA

Tarija, Bolivia

Congreso; XII Congreso Geológico Boliviano; 1996

Sociedad Geologica Boliviana

This paper reports isotope and chemical results of a study carried out in the northern basin of Mendoza. Deuterium, oxygen-18, carbon-14 and carbon-13 as well as major ions analyses performed on 121 samples of surface and three levels of groundwater lead to the following conclusions: there exist at least three different types of water in the basin, the related to the Mendoza River, very depleted in both, oxygen and deuterium, recharged at high altitude in the Cordillera de los Andes (d18O / -18.6 l and d2H / -140 l); the less negative, Tunuyán River water type, (d18O / - 16.7 l and d2H / -127 l) and those of the Pampa de Canota, more enriched (d18O / -6.8 l and d2H / -48 l), reflect the recharge coming from western lower hills. By means of the cited differences in the isotopic compositions, it was possible to differentiate the influence on the recharge for the three above mentioned water types. Most of the salinisation mechanisms are also explained here. Carbon-14 and carbon-13 data allowed, by using the modified Pearson model to asses the groundwater age and to calculate the groundwater flow velocity towards the NE the Tunuyán River and towards NW the Mendoza River in 4 and 3m/y, respectively.