Chapter 6.2 - Modeling of stratigraphic architecture of carbonate platform margin, Late Ordovician Lianglitage Formation, Central Tarim Basin

Abstract

According to the different geometric shapes and reflection characteristics of seismic profiles, the carbonate platform margins of the north slope of late Ordovician Lianglitage Formation in Tazhong uplift are summarized into three basic sedimentary architectures. One type mainly distributed in the west of the carbonate platform margin, from the platform interior to the platform margin there were obvious imbricated deposits. The second type is in the middle of the carbonate platform margin, which shows the regressive sequence in the same transgressive system domain period, and the slope strata in the platform margin show the regressive sequence in the high system domain period. The third type is located in the east of the carbonate platform margin and is a parallel sedimentary structure. The crossing well sections on the north slope of Tazhong carbonate platform show that the depositional thickness gradually thinned from east to west. The thickest zone is located to the east of the platform margin and thins rapidly toward the basin and the platform interior. It indicates that the paleogeomorphology of Tazhong uplift in the late Ordovician Lianglitage Formation may be high in the west and low in the east. According to the results of seismic profile interpretation and computer simulation, the sedimentary configuration of O3l-2 sequence is characterized by deposition, regression, and progression from east to west from the edge of carbonate platform during the transgression period. This means that along the northern edge of the carbonate platform of the Tazhong uplift, the space can be accommodated gradually decreases from east to west. The differences in admissibility may be caused by differences in tectonic subsidence. And computer-aided modeling can be used to deeply understand the importance of various control parameters on the carbonate platform depositional architectures and processes.