Researching of relationship between sequence stratigraphy, lithofacies and aquifer and aquifuge of Quaternary sediments in Thai Binh and Nam Dinh area

The Pleistocene aquifer in Thai Binh and Nam Dinh area is related to 5 riverbed sand facies complexes belonging to the lowstand systems tract and 5 highstand river mouth sandy bar sand facies complex with ages ranging from Early Pleistocene to late late Pleistocene: (1) (SaLSTQ11); (2) (SaLSTQ12a+SamHSTQ11); (3) (SaLSTQ12b+SamHSTQ12a); (4) (SaLSTQ13a+SamHSTQ12b; (5) (SaSTQ13b+SamHSTQ13a). Overlaying these 5 aquifers are 5 aquifuges including 5 transgessive systems tract shallow marine-bay mud facies complexes: (1) MmTSTQ11; (2) MmTSTQ12a; (3) MmTSTQ12b; (4) MmTSTQ13a; (5) MmTSTQ21-2. The process salinization of has been occurring in the Pleistocene aquifer in Nam Dinh and Thai Binh areas due to the permeation of meteorological water through shallow sea-bay marine mud facies complexes that act as aquitard layer. Residual salt water from aquitards mixed with the primitive freshwater aquifer of the lowstand systems tract river bed sand facies complex.