Four isolate barrier beds occurened usually in boundary surface of each internal architecture unit in channel sandbody, i. e. find bed, muddy pebble bed, plant clasts bed and diagenic bed.

在河道砂体内部构成的不实体界面，通常存在4挡，即细粒物质挡、泥砾挡、植物碎屑挡和成岩挡。