GEOQUÍMICA DAS ÁGUAS SUBTERRÂNEAS DA BACIA SEDIMENTAR DO CARIRI CEARENSE, NORDESTE DO BRASIL

Underground water geochemistry of the sedimentary basin of Cariri Cearense, Northeast of Brazil

Abstract

The wells under study are located in the Araripe Sedimentary Basin, in the southeastern region of the state of Ceará, comprising Abaiara, Barbalha, Brejo Santo, Crato, Milagres, Juazeiro do Norte, Missão Velha and Porteiras. The objective of this study is to use the results of the water analysis informed in the 2011 Report - COGERH, to identify processes and mechanisms that affect the chemistry of groundwater. The hydrochemical facies showed a predominance of mixed bicarbonated waters in the rainy and dry periods. The waters are mostly alkaline earth and weak acid anions. Few wells had reverse ion exchange and none had the dedolomitization process. The rock dominance is predominant, revealing the chemical weathering of rock-forming minerals influencing the quality of groundwater through its dissolution through which it circulates, there is also the possibility of carbonate weathering due to the abundance of Ca²⁺ and Mg²⁺. Geochemical modeling using WATEQ4F allowed to predict the saturation level of the minerals halite, gypsum, calcite and dolomite.