The researchers studied sedimentary characteristics in the lower Youshashan formation in the Neogene of Wunan area. They looked at different formations and found that the first and second formations were from flooded-lake gravity currents, while the third, fourth, and fifth formations were from a shadow lake-deltaic system. In the shadow lake delta, they identified delta plain and delta front facies. By studying these sedimentary features, they were able to understand the evolution of the sedimentary facies and predict the distribution of sandbodies in the future.