干盐湖阶段的沉积特征兼论钾盐矿层的形成

盐盆地演化到析钾阶段时,广袤的干盐滩与若干卤水湖并存。这种特殊的地质地埋背景称为“干盐湖”。察尔汉盆地是现代干盐湖的一个典型实例。由于选择性溶解作用使钾富集在水位最低的卤水湖内,并在干盐滩与卤水湖之间的平坦湖滨地带形成钾盐层。成钾机理与现代海滨萨布哈类似,但钾-镁盐类来源于干盐滩内的孔隙(晶间)卤水。

CHARACTERISTICS OF SALT DEPOSITS IN THE DRY SALT LAKE AND THE FORMATION OF POTASH BEDS

When a saline basin evolves into a stage of potash deposition a vast expanse of salina coexists with some brine lakes. Such a special geologic and geographic setting is known as a "dry salt lake" . The salt deposits in Qarhan Basin are cited as a typical example of a modern dry salt lake. The potassium compounds are enriched at the lowest water level in the brine lake by the processes of selective solution. The bedded potash deposits are usually formed in the flat lake beach along the bordering regions of salina and lake. The mechanism of formation of the potash beds is similar to modern coastal sabkha,but the K-Mg salts are supplied from the interstitial ( intercrystal ) brines in the salina.