The Muli Basin in China is a coal-rich area that also contains unique gases like coalbed methane. Scientists studied the rocks and fossils in the area to understand how coal formed there. They found that the basin went from having rivers to a lake over time, leading to the creation of thick coal layers. The coal mainly formed during certain stages of this process. This research helps us understand how coal can accumulate in different environments and how it can be used as an energy source.