A facies model is a conceptual framework used to interpret and predict the distribution of sedimentary facies within a depositional environment. These models help geologists understand the processes that control sediment deposition and the spatial relationships between different sedimentary units. Facies models are crucial in sedimentology, stratigraphy, and petroleum geology.
Reference: Walker, R. G., & James, N. P. (1992). Facies Models: Response to Sea Level Change. Geological Association of Canada.