Abstract

Based on the studying results of geological, hydrogeological structure, evolutionary history of sediments in the Study area and combined with isotopic results, this paper has identified a system of faults and fractures oriented northwest - southeast in the Triassic formations, the Pre-Cenozoic formations in Nam Định area and continental shelf of study area acting as a water reservoir and a canal system, it has facilitated the flow of water from the land towards the sea. In addition, the results of hydrogeological isotope studies have shown that, the Triassic, Neogene and Pleistocene aquifers in this area related to each other through hydraulic system in fractures, faults and porosities of aquifers, fresh groundwater aquifers in Pleistocene in study area are derived from meteorological water, groundwater age is from recent up to more than 11,300 years.