INGEIS   05370
INSTITUTO DE GEOCRONOLOGIA Y GEOLOGIA ISOTOPICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Caracterización Isotópica del Acuifero Guarani Aflorante en el Norte de Uruguay.
Autor/es:
COLLAZO, MARIA PAULA; DAPEÑA, CRISTINA; AUGE, MIGUEL; MONTAÑO, JORGE
Lugar:
Paraná, Entre Ríos
Reunión:
Congreso; V Congreso Argentino de Hidrogeología- Taller de Acuiferos Fronterizos; 2007
Institución organizadora:
Grupo Argentino Asociación Internacional de Hidrogeología y Facultad de Ciencias Agropecuarias de la Universidad Nacional de Entre Ríos
Resumen:
The outcrop
area of the Guaraní Aquifer (AG) is located in northern and northern-central
Uruguay, including parts of the Rivera and Tacuarembó departments. The outcropping
Guarani Aquifer (AGa), is made up of two units. The upper unit is restricted to
the North and contained in the Rivera Formation is named Rivera Unit (UR). The
lower unit is contained in the Tacuarembó Formation and occurs throughout all
the studied area, and is named Tacuarembó Unit (UT). The Rivera
Unit is made up of fine to medium reddish a eolian sandstone. It covers only
the 15 % of the AGa, its thickness being in average 65 m and reaching maximum
values of 100 m
at high topographic levels (250 to 300 m asl). The Tacuarembó Unit is made up of
fine to very fine sandstones, with clayey siltstone intercalations, of pale and
pink colours. Average thickness of this unit is 100 m. It represents a
hydrogeological unit of regional extension, of free to semiconfined behaviour.
The
isotopic composition (d2H, d18O)
of the total groundwater shows similar values to the averages measured in the
stations of the GNIP, indicating their meteoric origin. The values average d18O
and d2H
for the Unit Tacuarembó are respectively -5,6 and -31,5 and for the Unit
Rivera are -5,4 and -30,4. The contents of 3H of the aquifer
Rivera groundwater indicate smaller times of traffic and they are located in
the watershed divisor.