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通过资料搜集、蒸发岩野外露头地质调查、石盐岩沉积特征分析及盐类矿物学研究,对塔里木盆地塔西南坳陷中新生代蒸发岩的分布、层位、盐类矿物组合、成因进行了初步探讨。塔西南坳陷石盐岩沉积呈透镜体状,主要沿西昆仑山前分布,常含有褐红色、灰绿色泥砾,泥砾岩性与吐依洛克组下段岩性一致,推测应为吐依洛克组沉积晚期海退期成盐,其层位应归属于吐依洛克组上段。石盐岩透镜体在横向分布上不连续,反映了当时塔西南坳陷内部可能存在多个古盐湖次级凹地,其在干旱气候条件下经浓缩蒸发成盐。蒸发岩矿物除石盐、石膏外,还见有杂卤石、钙芒硝等,其中杂卤石可能为后期富钾卤水交代原生石膏的产物,而乌泊1井石盐表面大量的次生钙芒硝可能为盐湖后期石盐析出阶段含钙地下水缓慢持续补给盐湖的产物。
Through data collection, geological survey of outcrop of evaporite field, sedimentary characteristics analysis of salt rock and salt mineralogy, the distribution of Mesozoic-Cenozoic evaporites, formation, salt mineral assemblage and genesis in the southwestern Tarim basin in Tarim Basin were studied Preliminary discussion. The salt rock deposits in the southwestern Tarim Basin are lenticular in shape and are mainly distributed along the front of the West Kunlun Mountains. They often contain maroon, gray-green mudstone and conglomerate, which are consistent with the lithology of the lower part of the Turin-Locke Formation. In the Late Cretaceous sedimentation, the sediments of the Locke Formation were salt-formed, and their horizon should be attributed to the upper segment of the Turin-Locke Formation. The discontinuity of the rock salt lenses in the lateral distribution reflects that there may exist multiple secondary valleys of the ancient salt lake in the southwestern part of the basin, which were concentrated and evaporated into salt during arid climate. In addition to rock salt and gypsum, the evaporite minerals include polyhalite, glauber’s salt, etc. Among them, the polyhalite may be the product of the primary gypsum in the latter stage of potassium-rich brine, while the large amount of secondary glauberite It is possible that the calcium-containing groundwater will be slowly and continuously supplied to the salt lake for the precipitating phase of salt rock in the late stage of Salt Lake.