Full text loading...
-
Geoelectrical and Magnetic Profiling for Fracture-Zone Aquifers in a Crystalline Basement Terrain in Piaui State, Northeast Brazil
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 5th International Congress of the Brazilian Geophysical Society, Nov 1997, cp-299-00143
Abstract
Much of the semi-arid southeastern part of Piaui state in Brazil is underlain by crystalline basement which has experienced weathering leading to the formation of a weathered mantle. In parts of the crystalline terrain and especially in areas where the basement is significantly fractured, useable groundwater aquifers may be found at the base of the weathered layer. The village of Mandacaru is served by a low yield well and initial examination of the available geological and aeromagnetic maps suggest the possible presence of a linear structural feature in the vicinity of the village. The combined transient electromagnetic (TEM), de resistivity and magnetic profiling methods have been deployed to map possible lineations of concentrated fractures in the basement that may be groundwater aquifers. A good agreement is seen in the signatures of the three different techniques across a prospective linear conductive zone bordered by resistive ground enabling deductions to be made about the groundwater potential of the study area and the locations with good potential for well siting.