黄河三角洲（泄水）包卷层理的成因研究

黄河三角洲上发育了大量的（泄水）包卷层理,按形态和规模可以分为两类;一类是规模较小,呈规则褶曲状的包卷层理,其“背斜”尖锐紧闭“,”向斜“圆滑宽阔;另一类规模较大,高度在１０－２０ｃｍ左右,形态复杂,可以是直立圆柱状,直立板片状,也可以是直立卷曲板片状。

Genesis of the (Sluicing) Convolute Bedding in the Yellow River Delta

This study focuses on the convolute bedding. There are a lot of convolute beddings in the Yellow River delta. They may be divided into two kinds according to their shapes and sizes: one is small in size (ca. 3-5 cm high and ca. 3-5 cm wide) and its shape is like a regular fold. The "anticline" of the convolute bedding is chevrony and tight and the "syncline" is broad and smooth. The other is relatively large in size (ca. 10-20 cm high) and complex in shape, being either upright cylindrical and upright tabular or upright curly tabular. Whether in the first case or in the second the center of the convolute bedding is commonly marked by a sand "ball" and sometimes there is one or a few sluicing holes in the center. The study reveals that the convolute bedding is genetically related to rapid deposition and wave-shaking. Wave shaking makes the loose sediment sluicing, resulting in the inversion of the density gradient, instability and diapiric deformation, thus forming convolute bedding.