阿尔金断裂为边界的盆地斜坡带扇三角洲  

The Fan Delta in the Altun Slope Boundedby the Altun Rift System in the Qaidam Basin

作　　者：高剑波[1] 钟建华[1] 徐小林[1] 温志峰[1] 黄立功[2] 刘云田[2] 江波 

机构地区：[1]石油大学(华东)资信学院油气基础地质研究所,山东东营257061 [2]中国科学院广州地球化学研究所,广州510640 [3]中国石油青海油田分公司,甘肃敦煌736202

出　　处：《沉积学报》2004年第2期206-215,共10页Acta Sedimentologica Sinica

基　　金：CNPC中青年创新基金项目 (编号 :2 0 0F70 1 0 8);高校博士点基金项目 (编号 :2 0 0 30 4 2 50 0 8)资助

摘　　要：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 rift system, located in the western Qaidam Basin, is a key large-scale thrusting-sliding rift system, by which, the two great basins—Qaidam and Tarim are separated. The fan-delta, which is themain subject in this paper, is well developed in theTertiarystratum of the western Altun slope, next to the referredrift system above, that is in thenorth boundary of thewestern Qaidam Basin. With the help of the analyses of thetectonic dynamical evolution in Cenozoic era, thesupplying speed of thesediments, the augmentof the accommodation, thequalities of thebasin boundary, the distance between the source area and thebasin, as well as thedelicate description of theoutcrops and the discussion of their sedimentary characters, it is believed that, two kinds of sequenceseries are developed in thestudy area,i.e. the retrograded fan deltas and the prograded one. According to the studies above, two sedimentary models of thefan deltas have been illustrated considering the differences of the tectonic dynamicssettings. From our study, it is clear that, thecombination of the generating rocks, the reservoirsand the caprocks in thewestern parts of theAltun slope is fairly ideal. Thegyttjadark mudstones, distributed in theupside of the low-Gan Chaigou Group, are theprimary hydrocarbon source rocks; and thesand bodies of the subaquaticdistributary channels, the bars in the prograded fan delta and the braided channels in retrograded one can offer a good space for thepreserving and pooling of oil, and therefore, it is themost important object for theoil exploration in this area. The study of theTertiarfan deltas in the western Altun slope can offer a solid scientific base for the further study of thegeneration of theAltun Orogen.

关 键 词：扇三角洲 第三系 沉积学 生储盖组合 柴达木盆地 

分 类 号：P512.2[天文地球—地质学]