Contourite is an important sedimentary type of traction current deposits in a deep-water environment. Although there has been a lot of research on contourites, most studies focus on contour concurrent deposition in modern oceans by bathymetric investigation and deep-sea drilling (DSDP, ODP and IODP). Following the implementation of the IODP (Integrated Ocean Drilling Program)Expedition 339(The Mediterranean outflow),the study of contourites has reached a new stage for analyzing the vertical and lateral succession of contour drifts. However, there is still a great restriction on further study of contourites, especially on the depositional model for contour currents because of the big gap between modern sea floor and stratigraphic records. This article is focused on the ancient contour current deposits developed in the northwestern margin of the Ordos Basin,in Darriwilian Stage,Middle Ordovician.Sedimentology analysis based on the detailed field work in shixiagu section,Hainan area in Wuhai city of Inner Mongolia allows us to differentiate three vertical successions, i.e., the medium-to thin-bedded amalgamated limestone, the alternation of limestone-mudstone unit and mudstone,and the striation mudstone is the notable characteristics in the lower,middle,and upper part of the Kelimoli Formation, respectively. These three successions are proposed to represent the deposits of channel, levee, and basin in deep-water environments where contour currents dominate. Thus, a conceptual model of deep-water channel-levee system for the deposition of contour currents is developed from the geological records in the western Ordos Basin.%等深流沉积是深水环境中牵引流沉积的重要类型之一.虽然研究程度相对较高,但主要以深海测量和大洋钻探为平台对现代海洋中的等深流进行研究,特别是大洋钻探339航次的执行,将等深流沉积研究推向一个新的阶段(等深岩丘结构剖析),而对地层记录中的等深流沉积研究却非常薄弱,从而也制约了对等深流沉积的研究,特别是等深流沉积模式的建立.鄂尔多斯盆地西缘北部桌子山地区中奥陶统达瑞威尔阶克里摩里组广泛发育等深流沉积,此次在详细的野外观察基础上,对内蒙古乌海市海南区石峡谷剖面进行沉积学研究,该剖面克里摩里组从下到上可分为三段:下段以薄-中层叠置石灰岩为特征、中段以石灰岩-泥岩岩组与泥岩互层为特征,上段以条纹状泥岩为特征.三段沉积分别代表了深水环境下等深流水道沉积、天然堤沉积和深水盆地平原区极弱等深流沉积,在垂向上组成了一个完整的等深流水下水道-天然堤沉积体系.
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