【摘要】 探讨鄂尔多斯盆地东南部地区奥陶系马家沟组上组合沉积微相类型、特征以及展布规律。通过对典型钻井岩心和野外剖面进行岩石类型、结构构造的研究,对研究区的沉积微相进行识别,研究其发育特征,再现其时空分布规律。结合各单井相分析,系统编制各层系的岩相古地理图件;在相分析和古地理研究基础上,开展岩相古地理演化过程分析,揭示沉积古地理演化规律。结果表明马家沟组上组合主要发育泥云坪微相、灰云坪微相、膏云坪微相和含膏云坪微相。从马五₄沉积期到马五₁沉积期相对海平面逐渐降低,而海平面的降低控制了沉积微相的发育和空间展布。更多还原

【Abstract】 The study of lithology, texture and structure of the drilling cores and field sections of the Upper Ordovician Majiagou Formation in southeastern Ordos Basin is carried out in order to identify the sedimentary microfacies, unravel the development characteristics and reproduce the spatial and temporal distribution law. Each single well facies is analyzed and the lithofacies paleogeographic maps of each stratum are systematically compiled. Based on the microfacies and paleogeographic research, the lithofacies paleogeographic evolution process is analyzed and the sedimentary paleogeographic evolution law is unraveled. It shows that the Majiagou Formation in the study area is mainly composed of pelitic dolomite flat, gypsum-bearing dolomite flat, gypsum dolomite flat and gypseous dolostone flat. From the deposition period of M5₄ to the deposition period of M5₁, the relative sea level is gradually lowing, while the decrease of sea level controls the development and spatial distribution of sedimentary microfacies.更多还原