Portal de Periódicos da CAPES

ESTUDO DAS CONDIÇÕES HIDROGEOLÓGICAS E HIDROQUÍMICAS DOS AQÜÍFEROS DA REGIÃO DE BIRITINGA - PATAÍBA (BA) UTILIZANDO MÉTODOS GEOFÍSICOS ELÉTRICOS

1986; Sociedade Brasileira de Geologia; Volume: 16; Issue: 3 Linguagem: Inglês

10.25249/0375-7536.1986176186

2177-4382

Iara Brandão de Oliveira, Olivar A. L. de Lima,

Geography and Environmental Studies

Drill holes which tapped the aquífers of the Ilhas and Massacará Groups in many places of the Tucano Sedimentary Basin produce water with a high content of díssolved salts. In order to optimize a procedure to determine the two dimensional extent of the salt water occurrence, as well as to contribute to the understanding of possible mechanisms responsible for this salinization, geophysical studies were made in the Biritínga-Paraíba area in the State of Bahia. Twenty eight (28) vertical electrical soundíngs, electrical logs of 13 wells and chemical analysis of 35 samples of groundwater allowed to determine the structural configuration of the Ilhas-Massacará aquífer system in the region, and to estimate the influence of this configuration on the chemical characteristics of the groundwater. In the study region the system consists of a vertical sequence of sandstone and shale layers dipping SE, which are longitudinally sectioned by gravity faults in a sequence of horsts and grabens. In the horsts where the system contains a high shale-sandstone proportion, the water ís more salty. Furthermore, some of the structural blocks have shown an íncrease of water salinity with depth. These facts seem to indicate that ionic filtering by the shales in the system and a process of mixing and hydrodynamic díspersion along the faults are the main controllers of the characterístícs of the groundwater. The results also indicate that under favorable conditions, information about the block structure system and water characteristics can be inferred from surface electrical soundings.