The South Atlantic coast in Argentine Patagonia is an area where semi-arid to arid conditions predominate and coastal populations present serious water supply problems. The aim of the work was to evaluate the factors that condition the salinization processes of coastal aquifers from a hydrochemical and isotopic analysis of the groundwater located in Pleistocene and Holocene littoral ridges in the northern sector of Patagonia in Bahía San Blas. A geomorphological characterization of the area was carried out using digital elevation models, satellite image interpretation and field surveys. Groundwater chemistry was analyzed in 40 shallow wells and 2 tidal water samples. At each point, electrical conductivity, temperature and pH of water were measured and samples were taken for analysis of major ions and stable isotopes. The salinization processes were analyzed by means of ionic and isotopic relationship graphs and were subsequently modeled using free software. The results obtained allowed the identification of the factors that determine the salinization of coastal aquifers. Particularly in the Pleistocene coastal ridges, the cementation of the most superficial sediments reduces permeability conditioning rainwater infiltration. This, together with the presence of soluble salts on the surface and the mixing with sea water, determines the salinization of the groundwater. In contrast to these, in the Holocene coastal ridges without cementation, rainwater infiltrates forming freshwater lenses where salinization processes occur only at the edges of the lenses where the saltwater wedge is located. The data provided in this paper are useful in prospecting freshwater sources along the arid coast of Patagonia where freshwater availability is scarce. They can also be extrapolated to other sectors worldwide with similar geological and climatic environments.

阿根廷巴塔哥尼亚南部大西洋沿岸地区是半干旱至干旱条件占主导地位的地区，沿海人口面临严重的供水问题。这项工作的目的是通过对巴伊亚州圣布拉斯巴塔哥尼亚北部地区的更新世和全新世沿海山脊中的地下水进行水化学和同位素分析，评估影响沿海含水层盐渍化过程的因素。使用数字高程模型，卫星图像解释和野外勘测对区域进行了地貌表征。在40个浅井和2个潮汐水样品中分析了地下水化学成分。在每个点上，测量水的电导率，温度和pH值，并取样以分析主要离子和稳定同位素。通过离子和同位素关系图分析盐碱化过程，随后使用免费软件对其进行建模。获得的结果可以确定决定沿海含水层盐碱化的因素。特别是在更新世的沿海山脊中，最表层沉积物的胶结作用降低了渗透性，调节了雨水的渗透。这与表面上可溶性盐的存在以及与海水的混合一起决定了地下水的盐碱化。与此相反，在没有胶结的全新世沿海山脊中，雨水渗入形成淡水晶状体，而盐化过程仅在咸水楔所处的晶状体边缘发生。本文提供的数据可用于在巴塔哥尼亚干旱沿海地区寻找淡水，那里的淡水稀缺。它们也可以推断到全球其他具有相似地质和气候环境的部门。