The Shahrokht-Yazdan Playa is a sedimentary inland basin in the east of Iran and west of Afghanistan. It covers an area of 212.5 km², lying 135 km northeast of Qayen at a border region known as Shahrokht. Some parts of the playa have stretched into Afghanistan (Yazdan area). In this playa, water level is controlled by the amount of rainfall, evaporation and groundwater recharge. To study the brine’s origin and evolution, some 95 water samples with specified intervals of 1 km were taken. The geochemistry of the brines was undertaken using the ICP-MS method and X-ray diffraction analysis on the sediments, the ionic concentrations of brine and mineralogical composition of sediments were identified. Major cations, as per their abundance, are sodium, calcium, magnesium and potassium and anions are chloride, sulphate and hydrogen carbonate, respectively. The results showed that the sediments of the lake’s bed were composed of chemical (evaporite) and clastic minerals (quartz, feldspar, muscovite and some clay minerals). Dominant evaporite minerals in sediments are gypsum, halite, calcite and dolomite while the minor mineral is clinochlore. Careful examination of surface samples indicates that carbonate and sulphate minerals deposited in the margins and minerals such as halite deposited as highly soluble in the centre of the playa. Chemical analyses of inflow water indicate that water has a molar ratio of \( {\mathrm{Ca}}^{2+}>{\mathrm{CO}}_3^{2-} \), Cl⁻+ \( {\mathrm{SO}}_4^{2-}>{\mathrm{HCO}}_3^{-},\kern0.5em {\mathrm{HCO}}_3^{-}\ll {\mathrm{Ca}}^{2+}+{\mathrm{Mg}}^{2+} \) and is following the same second geochemical path (II) as that of Saline Valley and Dead Valley brine lakes on the brine evolution flow diagram. The inflow water to the basin is of the Na⁺-(Ca²⁺)-(Mg²⁺) \( {\mathrm{SO}}_4^{2-} \)-Cl⁻-(\( {\mathrm{CO}}_3^{2-} \)) type which changes into Na⁺-Cl⁻-\( {\mathrm{SO}}_4^{2-} \) type during the geochemical evolution and deposition of evaporate minerals. In order to investigate the origin of major ions in the brine, the groundwater of the surrounding desert, which is the only supplier of ions to this area, was studied. The relationships between groundwater and regional brine were investigated. The study of the chemical changes of the brines in relation to the sedimentation of evaporite minerals indicates marked evolution of the brines in Shahrokht-Yazdan Playa to in so far as the formation of chloride minerals and type brines Na⁺-Cl⁻-\( {\mathrm{SO}}_4^{2-} \) occurred. The study of correlational relations with the help of SPSS software also shows the formation of carbonate and sulphate minerals in this playa and the saturation of brine from chloride.

Shahrokht-Yazdan Playa是位于伊朗东部和阿富汗西部的沉积内陆盆地。占地面积212.5 km ²，位于盖恩东北135公里处的边境地区Shahrokht。普拉亚的某些地区已经延伸到阿富汗（亚兹丹地区）。在这个海滩中，水位由降雨，蒸发和地下水补给量控制。为了研究盐水的起源和演变，抽取了95个水样，指定间隔为1 km。使用ICP-MS方法对盐水进行地球化学分析，并对沉积物进行X射线衍射分析，确定了盐水的离子浓度和沉积物的矿物学组成。就其丰度而言，主要的阳离子是钠，钙，镁和钾，而阴离子分别是氯离子，硫酸根和碳酸氢根。结果表明，湖床的沉积物由化学物质（蒸发岩）和碎屑矿物（石英，长石，白云母和一些粘土矿物。沉积物中主要的蒸发矿物为石膏，盐岩，方解石和白云石，次要矿物为斜绿石。仔细检查表面样本可发现，沉积在边缘的碳酸盐和硫酸盐矿物以及沉积在海滩中央的高度易溶的矿物（如盐岩）。流入水的化学分析表明，水的摩尔比为\（{\ mathrm {钙}} ^ {2 +}> {\ mathrm {CO}} _ 3 ^ {2-} \），氯^- + \（{\ mathrm {SO}} _ 4 ^ {2 - }> {\ mathrm {HCO}} _ 3 ^ {-}，\ kern0.5em {\ mathrm {HCO}} _ 3 ^ {-} \ ll {\ mathrm {Ca}} ^ {2 +} + {\ mathrm {Mg} } ^ {2+} \），并且遵循与盐水演化流程图上的盐谷和死谷盐水湖相同的第二条地球化学路径（II）。流入盆地的水为Na ⁺ -（Ca 2 ⁺）-（Mg 2 ⁺）\（{\ mathrm {SO}} _ 4 ^ {2-} \）^- Cl --（\（{\ mathrm {CO}} _ 3 ^ {2-} \）），其改变成Na型⁺ -Cl ^- - \（{\ mathrm {SO}} _ 4 ^ {2-} \）地球化学演化和蒸发矿物沉积过程中的类型。为了调查盐水中主要离子的来源，研究了周围沙漠的地下水，该地区是该区域唯一的离子供应商。研究了地下水与区域盐水之间的关系。相对于蒸发盐矿物的沉降卤水的化学变化的研究表明，只要氯化物矿物质和类型的形成标志着Shahrokht-Yazdan滩卤水的演化到卤水的Na ⁺ -Cl ^- - \（{ \ mathrm {SO}} _ 4 ^ {2-} \）发生。借助SPSS软件对相关关系进行的研究还表明，该滩中碳酸盐和硫酸盐矿物的形成以及氯化物对盐水的饱和度。