Review of Mixed Sedimentation Studies

Since the 1950s, mixed sedimentation has come into people's attention, and has gradually become the research direction of sedimentology. On the basis of previous studies, the research progress of mixed deposition at home and abroad is summarized, and some problems and prospects of mixed deposition are put forward. Mixed sediment is widely developed in Marine and lake sedimentary environments. As a special sediment with complex sedimentary patterns, it is controlled by many factors such as terrigenous supply, climate change, sea level change, hydrodynamic conditions, tectonic action and so on. The genetic types of mixed sediments generally include intermittent mixing, facies mixing, insitu mixing and source mixing. Mixed sedimentary rocks include mixed sedimentary rocks and mixed sedimentary strata. The classification of mixed sedimentary rocks was first proposed by predecessors, and now it adopts more three-end element method. Mixed deposition has important oil and gas geological significance, and there are still some problems to be solved, including the establishment and improvement of sedimentary models in different sedimentary environments, the unified naming and lithology identification of mixed deposits, and the prediction of mixed deposits, etc. These studies are of great significance to the oil and gas exploration and development of mixed deposits.