羌塘盆地中央隆起带南侧隆额尼-昂达尔错布曲组古油藏白云岩稀土元素特征及成因意义

以系统的岩石学及沉积相分析为基础，深入探讨了隆额尼—昂达尔错古油藏白云岩及其伴生灰岩的稀土元素地球化学特征，认为该区灰岩及白云岩∑REE仍受沉积相带及沉积过程的控制，且具∑REE较低的总体特征，白云岩中HREE比LREE更具贫化的特点，这些特征均系淡水淋漓作用的结果；灰岩及白云岩在配分模式上，均为相对平坦的页岩配分模式。其中灰岩在配分模式上，在∑REE较高的情况下表现出起伏较大的特点，而白云岩在∑REE较低的情况下，表现出较为平坦的特征，白云岩化过程中稀土元素有贫化和均一的趋势；灰岩与白云岩相比，灰岩δEu值较高，而白云岩δCe较高，反映出灰岩形成于水体较深的还原环境，而白云岩形成于古地理相对高点的氧化环境。该区白云岩为混合水交代成因。

Characteristics of the Paleo-Oil Dolomite REE Geochemistry of Buqu Formation in Southern Part of the Central Uplift Zone of Qiangtang Basin and It's Significance

Based on systematic analysis of lithological composition, microstructure and sedimentary facies, in this paper many discusses have been conducted for the REE characteristics of Longeni Angdanrco paleo oil dolomite in southern part of the central uplift zone of Qiangtang basin. The amount of ∑REE in dolomite and concomitant calcite is lower in comparison with other carbonates in China, and is still under the control of sedimentary facies and process. The HREE of dolomite is even more impoverished than LREE compared to concomitant calcite in this area. In distributed patterns, all the carbonates show a complicate model, and the dolomite is even more flat compared to concomitant calcite. For the two typical indexes, the δEu of calcite is higher, and the δCe of dolomite is higher. All these show that REE have been undergoing an impoverished process in dolomitization, and the calcite has been formed in deep water deoxidized environment, the dolomite being formed in shallow water oxidized environment. The dolomite in this area should be the result of mixed water replacement to calcite.