It is demonstrated that the west of the depression was the main source supply area during S4 period, where had developed 4 major sources and formed fan delta sands like Shen257, Shen225.

• 阐明了沙四时期凹陷西侧为主要物源供给区，发育4个主要物源，形成了沈257、沈225、沈267、沈278等扇三角洲砂体。