The article explores how sedimentary rocks from the Middle and Lower Jurassic periods formed in the Maling Oilfield. By studying various data sources, researchers identified different types of sedimentary environments, such as rivers and lakes. They found that the area went through stages of cutting, filling, and rising, leading to the development of river and delta systems. The Fuxian and Yanan Formations in the southern Ordos Basin show a transition from fan rivers to lake deltas, with coal deposits forming during periods of river activity and basin uplift.