From down to up they respectively are named sequence 1 and sequence 2 . qingshankou formation borders by g3 sandbody . the formation inside its is lake expanding system tract of sequence 1 , and on its is lake contracting system tract 青山口组以g _ 3砂体为界,其下是层序1的湖泊扩张体系域,其上是层序1的湖泊萎缩体系域。