The Source-to-Sink System in Continental Rift Lacustrine Basins of the Nantun Formation in X Sag of the Tamtsag Basin, Mongolia

The strata of the 1 member of the Nantun Formation are the key targets for oil and gas development in the Sag X of Tamtsag Basin. Due to differences such as provenance supply, the growth and evolution of the boundary faults, and sediment transportation paths, various source-to-sink (S2S) systems have developed, and the distribution pattern of sand bodies remains unclear. It conducts a detailed characterization of different types of S2S systems. The results show that: (1) The activity of the boundary faults in the 1 member of the Nantun Formation gradually increases, controlling the development of paleovalleys and the migration of the subsidence center and depocenter. (2) Three types of S2S systems have developed in the study area, namely the “transverse drainage - fan delta” type, the “transverse drainage - braided river delta” type, and the “axial drainage - braided river delta” type. The distributions of different kinds of S2S systems show inheritance. (3) The growth and evolution of the boundary faults controlling the sag and the intensity of provenance supply control the evolution of the S2S system.