The study shows that Ess is mainly consisted of meandering deltaic sediments of fine particles, which mainly includes fine sandstones, siltstones, vertical sequency presents unnormally-graded.

• 研究表明,沙三段以曲流河三角洲沉积为主,沉积物粒度细,以细砂岩、粉砂岩为主,垂向层序总体表现为向上变粗的反旋回层序。