塔里木盆地古城地区上寒武统白云岩稀土元素地球化学特征及成因模式

塔里木盆地古城地区特殊的沉积构造演化，预示着其白云岩的形成可能有其特殊性。以古城构造带上寒武统白云岩为研究对象，在岩心、薄片、沉积环境分析的基础上，对各类结晶白云岩及缝洞白云石、方解石充填物进行了稀土元素地球化学特征分析。结果表明，各类白云岩及缝洞充填物稀土元素NASC配分模式共分为4种类型:δCe负异常δEu弱正异常型、δEu负异常型、δEu正异常型和δCe正异常型。详解白云岩及缝洞充填物的成因，蒸发泵作用是古城地区白云岩的主要成因类型，热液作用也非常显著，而埋藏作用和混合水作用影响较小。此外，所有测试的缝洞充填物都是在混合水环境和热液环境中形成的，蒸发作用和埋藏作用并没有形成明显的充填物，这可能对寻找有利的白云岩储层有一定的借鉴意义。 

Geochemical characteristics and genetic model of rare earth elements in the Upper Cambrian dolomites in Gucheng area,Tarim Basin

The special sedimentary and tectonic evolution in Gucheng area of the Tarim Basin indicated that dolomite formation might be unique. The REE geochemical characteristics of various kinds of crystalline dolomites and cave fillings were analyzed based on thin sections, cores and sedimentary environment analyses. The results showed that the NASC normalized REE distribution patterns of samples can be divided into four types: negative anomaly δCe and weak positive anomaly δEu, negative anomaly δEu, positive anomaly δEu, and positive anomaly δCe. Further studies showed that the main origin of dolomites was the evaporation pump model, and the hydrothermal environment was also important, while the influence of mixed water and burial dolomitization was relatively smaller. In addition, all the cave filling samples were formed in a mixed water and hydrothermal environment, while the evaporation pump and burial dolomitization did not form any filling samples, which might be helpful to find dolomite reservoirs.