Integração de análise hidroquímica à geofísica aérea para entendimento da hidrodinâmica no entorno da Lagoa da Confusão, Tocantins, Brasil

Integration of hydrochemical analysis with aerial geophysics to understand the hydrodynamics around Lagoa da Confusão, Tocantins, Brazil

Abstract

Aerial geophysics, stable isotopes and hydrochemical data analysis were used to understand the dynamics of water flows and the characteristics of surface and groundwater in the surroundings of Lagoa da Confusão - State of Tocantins, Brazil, in order to contribute for a better management of water resources in the area assumed to be an overgrown karst and to subsidize actions to protect the environment. Aerial geophysical data showed three typologies: carbonate rocks, diverse metasedimentary rocks and laterites. Numerous parallel lineaments were identified, including large faults, in the preferential N-S and E-W directions and, subordinately, 45ºNE and 45ºNW, which show strong control in the surface drainage network. It is interpreted that the Lagoa da Confusão is located on a carbonate substrate. The isotopic and hydrochemical analyzes indicate the occurrence of the karstification process in the study area, in which the chemical and isotopic composition of water is altered by the water-rock interaction and dissolution of carbonate rocks, which is further evidenced by the occurrence of caves and sinkholes (ipucas).