| On the basis of the sequence stratigraphic framework, the sedimentation of Ordovician in the Yubei area of Tarim Basin was studied through the analysis of core, drilling, logging, seismic and palaeontological data. The results show that six sedimentary facies are developed during the Ordovician Period in the studied area, including platform tidal flat, restricted platform, open platform, platform margin, continental margin slope, and shelf. The lateral distribution of sedimentary facies of Ordovician Period were characterized respectively. The characteristics of vertical sedimentary evolution were summarized as follows: At the early stage of Early Ordovician the platform tidal flat facies were developed, and at the late stage, the transitional restricted platform were formed by sea-level rise continuously and gradually, then the open platform facies were developed at Middle Ordovician. At the early stage of Late Ordovician, the slope facies were developed, and at the late stage of Late Ordovician, the shelf depositional system was developed. By the comprehensive analysis of the lateral distribution and vertical evolution of Ordovician sedimentary facies, and the palaeogeographic sedimentary environment, and the controlling factors, the sedimentary evolution models of Ordovician in Yubei area were established. |
