IDENTIFICAÇÃO DE CÉLULA DE FLUXO LOCAL NO SISTEMA AQÜÍFERO GUARANI: ESTUDO DE CASO NO VALE DO RIO TAQUARI, RS, BRASIL.

Abstract

The Guarani Aquifer System (GAS) in Rio Taquari valley region, Rio Grande do Sul state, southern Brazil, was investigated using data generated by a detailed hydrogeological survey performed in a mineral water occurrence, regional stratigraphic and stuctural survey and reinterpretation of lithologic and hydrogeochemical data from water wells belonging to a public water supply system. Due the effects of Dorsal de Canguçu fault system, in the transition zone between eastern and central sectors of GAS in southern Brazil, the tectonics define flow cells elongated according NE and controls the stratigraphy, suppressing Botucatu Formation from the lithological record. A secondary fault system, trending NW, also affects the Botucatu Aquifer but maintaining hydraulic connection between blocks. In one of these blocks, based in stratigraphic, textural and hydrochemical criteria, the Passo das Tropas Aquifer was identified. The flow barriers represented by NE trending faults and the existence of Passo das Tropas aquifer demands revision of conceptual ad flow models of GAS in the study area, better described as a composition of independent flow cells for each aquifer.Keywords: Guarani Aquifer System, flow cells, hydrostratigraphy