Hydrogeochemical and Flow Modeling of Aquitard Percolation in the Cariri Valley-Northeast Brazil
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- 作者：Carlos Jos¨¦ Freire Machado ; Maria Marl¨²cia Freitas Santiago ; Luiz Alberto Ribeiro Mendon?a ; Horst Frischkorn and Josu¨¦ Mendes Filho
- 关键词：Hydrogeochemistry ; PHREEQC ; Modflow ; Araripe Sedimentary Basin ; Cariri Valley
- 刊名：Aquatic Geochemistry
- 出版年：2007
- 出版时间：June, 2007
- 年：2007
- 卷：13
- 期：2
- 页码：187-196
- 全文大小：424 KB
文摘
Flow modeling and hydrogeochemical inversion calculations were performed on the aquifer systems of the Crato-Juazeiro Graben in the Araripe Sedimentary Basin of the Cariri Valley, Northeast Brazil, in order to assess aquifer interconnections through an aquitard of the Araripe Plateau. Steady state hydraulic head numeric calculations with the finite difference method used Modflow software with hydrologically based boundary conditions and a piezometric surface as initial condition. Hydrogeochemical inversion with PHREEQC was performed for two water samples representing typical initial and final waters along the flow path. Flow simulation shows that approximately 20 % of all recharge water from the superior aquifer system passes through the Santana aquitard reaching the middle aquifer system. Quantification of mineral dissolution/precipitation processes, ion exchange and microbiological redox reactions taking place in the aquifer systems also indicates hydraulic interconnection of the superior and middle aquifer systems through the Santana aquitard.