期刊名称：International Research Journal of Earth Sciences
电子版ISSN：2321-2527
出版年度：2016
卷号：4
期号：11
页码：17-24
语种：English
出版社：International Science Community Association
摘要：Hydrochemical studies were undertaken for understanding the evolution of chemical process in the sedimentary aquifer basement of Mahafaly region, southwest of Madagascar. Four mainly groundwater types have been observed according to the geological formation: i. less mineralized groundwater with type of Na-Ca-Cl-HCO3, from the phreatic aquifer of Isalo sandstone and clays formation covered by sandy shells in the Betioky hill, ii. more mineralized groundwater with type of Na-SO4-Cl or Na-SO4-Cl from Isalo sandstone formation at the east, iii. more mineralized groundwater dominated by Na-Ca-Mg-SO4-Cl-HCO3 water type, from the phreatic aquifer of the Jurassic and cretaceous formation, iv. groundwater from the alluvium formation at the Sakamena basin with Na-Ca-SO4-HCO3 water type. Saturation index results indicated that all groundwater in the study zone have negative values corresponding to under saturation of gypsum and halite while more samples have positive values on calcite and dolomite. Halite, calcite and gypsum dissolution, exchange of cation and precipitation of calcium bicarbonate are identified as dominants chemical processes conducting the evolution of groundwater mineralization in sedimentary aquifer of Betioky basin.
关键词：Geochemical;Groundwater;Mineralization;Mahafaly;South-western of Madagascar
