An isotope and solute evaluation was applied to identify the origin and mechanisms of groundwater salinization in three major Tertiary aquifers in the Rub’ al Khali topographic basin. We demonstrate that the groundwater chemistry evolved from a low- (1800 ppm) to high- (>120,000 ppm) salinity Na–Cl water type, regardless of the aquifer. The similarity in water types between the groundwater from the different formations suggests that the same origin and geochemical processes may be controlling the salinity and major ion chemistry in these aquifers. The suite of hydrogeological, hydrochemical (Cl vs. Br), and isotopic (Cl vs δ¹⁸O and Br vs δ⁸¹Br) data indicates that the source of solutes is associated with the entrapment of evaporated paleo-seawater (connate water) in nearshore and lagoonal environments during the time of deposition. Moreover, the results from the ⁸⁷Sr/⁸⁶Sr ratios show no evidence of significant vertical connectivity between the three Tertiary aquifers. Instead, the data support that evaporated paleo-seawater was trapped in each aquifer individually during the time of deposition, and that each has evolved similarly through water-rock and redox reactions. The stable isotopic compositions of δ¹⁸O, δ²H, and ¹⁴C show that the entrapped paleo-seawater was partially flushed out by fresh meteoric water during the Late Pleistocene and Early Holocene periods.

进行了同位素和溶质评估，以确定了Rub'al Khali地形盆地三个主要第三纪含水层中地下水盐碱化的起源和机理。我们证明了地下水化学性质从低盐度（1800 ppm）演变为高盐度（> 120,000 ppm）Na-Cl水类型，而与含水层无关。不同地层的地下水之间水类型的相似性表明，相同的来源和地球化学过程可能正在控制这些含水层的盐度和主要离子化学性质。的水文地质套件，水化学（CL与Br）和同位素（CL VSδ ¹⁸ O和溴VSδ ⁸¹Br）数据表明，在沉积期间，溶质的来源与蒸发的古海水（原生水）在近岸和泻湖环境中的滞留有关。此外，从⁸⁷ Sr / ⁸⁶ Sr比率得出的结果表明，没有证据表明这三个第三层含水层之间存在明显的垂直连通性。取而代之的是，蒸发的古海水在沉积期间分别被困在每个含水层中的数据支持，并且每个数据支持都通过水-岩和氧化还原反应而类似地演化。δ的稳定同位素组成¹⁸ O，δ ² H，和¹⁴C表明，在更新世晚期和全新世早期，被困的古海水被新鲜的陨石水部分冲走。