柴达木盆地西部油泉子凹地晶间卤水层水文地质及水化学特征

油泉子凹地位于柴达木盆地西部,凹地中蒸发岩的晶间孔隙发育,包含了大量的高浓度卤水,KCl品位高,富水性中等,水化学类型有氯化物型、硫酸镁亚型、硫酸钠亚型。研究表明,周边山区岩石中钾、硼、锂、钠、镁等元素物理风化后经流水搬运,形成了研究区丰富的钾盐矿物质;相关元素比值反映了矿区卤水陆相来源、溶滤水的成因特点。研究显示,研究区内地下水的密度、矿化度均有由西向东逐渐变淡的趋势;水文地质条件表明,季节性洪水、大汽降水是卤水重要的补给源。研究区地势低洼,地下水的排泄方式主要为蒸发排泄,形成了具有典型内陆蒸发型的水文地球化学特征,因此富集了大量高矿化度、且含多种金属离子的咸卤水。

Hydrogeologic and geochemical characters of intercrystal brine in Youquanzi concave in the west of Qaidam basin

Youquanzi concave is a late Pleistocene and Holocene sediment concave located in the west of Qaidam basin. Intercrystall pore is the important reservoir space with large volume of highly concentrated brine. The brine is characterized by high grade KCl and medium watery. There are several hydrochemical types including chloride type, magnesium sulfate subtype, sodium sulfate subtype. Previous studies indicate that potassium, boron, lithium, sodium, magnesium from the surrounding mountains are freeed by erosion and transported and accumulated into the lake region by water. Ratios of correlative elements reflect that the brine is derived from continent characteristic of lixivial water. The density and salinity of ground water show the tendency of desalination from the west to east and hydrogeological condition shows seasonal flood and the atmospheric water are the important supply sources. The study area is a low-lying area with dominant evaporation drainage of ground water and characteristic intracontinental evaporation hydrogeology and large volume of multi-metal ion-bearing, highly concentrated brine.