That the black mudstone deposited in deep water interbedded with salt and gypsum deposited in shallow water shows that during the sedimentation of 3(superscript rd) and 4(superscript th) sub-member, the lake level changes frequently.

• 也正是由于湖平面变化频繁，在沉积中心的周围主要物源方向上形成一系列低水位期的砂体。