Estudo geofísico para a caracterização geológica e hidrogeológica da subsuperfície rasa em área de deposição de rejeitos sólidos no município de Barcarena-PA

Abstract

This geophysical study was carried out in the ALBRAS Solid Refuse Deposition Area located in Barcarena, State of Pará. The results allowed to characterize the subsurface, giving information on the geological layers and hidrogeological parameters like direction and velocity of underground flow. Three geophysical methods were used in the study: Spontaneous potential, dc-resistivity, and electromagnetic (slingram). During the study, an experiment of infiltration of salty water in the ground was performed and monitored through electrical imaging. Spontaneous potential gave information on the direction of local underground flow of water. Electrical imaging allowed to estimate the velocity and the direction of underground flow along the imaging profile. The models obtained from the inversion of vertical electrical sounding apparent resistivity data showed a good correlation with gamma ray logging run in wells in the studied area. The interpreted resitivity and thickness of the models provided detailing for the shallow lithological units. Analysis of electromagnetic data on profiles, soundings, and contouring maps lead to the identification of conductive zones (clayed material) and resistive zones (sandy material). Besides, a good correlation among 14080 Hz electromagnetic contouring map and spontaneous potential map was observed.