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柴达木盆地西部阿尔金断裂系是分割柴达木与塔里木盆地的一条重要的大型逆冲—走滑断裂系 ,其南缘斜坡西段第三系广泛发育扇三角洲沉积。通过对盆地形成的构造动力学背景及沉积物供给速率、可容空间增长速率、盆地边界条件、源区与湖盆距离等条件分析入手 ,在大量野外露头精细描述和沉积特征论述的基础上 ,认为阿尔金斜坡西段第三系发育两种层序序列类型的扇三角洲 :退积型和进积型。在此基础上建立了两种扇三角洲沉积模式。阿尔金斜坡西段生储盖组合发育较好。下干柴沟组上部湖相暗色泥岩为主要的烃源岩 ,进积型扇三角洲前缘水下分流河道、河口坝 ,以及退积型水下辫状河道砂体具有较好的储集性能和成藏条件 ,是本区油气勘探的重点。阿尔金斜坡西段第三系扇三角洲的研究为深入讨论阿尔金造山带的形成演化提供了沉积学方面的依据。
The Altun fault system in the west of the Qaidam basin is an important large-scale thrust-strike-slip fault system that divides the Qaidam and Tarim Basin. The fan delta was extensively developed in the Tertiary in the western part of the southern margin of the southern margin. Based on the tectonic dynamics background and the sediment supply rate, the growth rate of the tolerable space, the boundary conditions of the basin and the distance between the source area and the lake basin, based on a large amount of exposition description and sedimentary characteristics, The Tertiary in the western segment of the Altyn Slope is thought to be of fan delta with two sequence types: retrograde and progressive. On this basis, two fan delta depositional models were established. The Altyn Tagh western segment has good development of reservoir-cap combination. The upper lake facies dark mudstone in the lower Ganchaigou Formation is the main hydrocarbon source rock, and the progressive distributary delta front subaqueous distributary channel, estuarine dam and retrograde underwater braided channel sandbody have good reservoir properties And accumulation conditions, is the focus of oil and gas exploration in this area. The study of the Tertiary fan delta in the western part of the Altyn Slope provides the basis of sedimentology for further discussion of the formation and evolution of the Altyn Tagh orogenic belt.