Abstract Manchuriophycus-like elliptical cracks are found in thin mudstone layers and lenses intercalated with wave-rippled lacustrine sandstone beds of the Lower Cretaceous Jinju Formation, South Korea. The cracks are interpreted as intrastratal shrinkage cracks formed by liquidization and injection of sand, hydroplastic deformation of mud, and concomitant dewatering of the sediments in water-saturated conditions. The cracks are considered to have been formed by earthquake and/or wave-induced loading and initiated where smectite was presumed to be locally concentrated in the mud. It is hypothesized that the cracks were developed into the elliptical outline, reflecting that of an interference ripple trough, due to permeability differences between two thin mud layers deposited over the rippled sand layer.

中文翻译：

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湖相砂岩夹层薄泥岩中的类满藻类椭圆裂缝：水饱和沉积物中地层裂缝的形成

摘要 韩国下白垩统晋州组波浪纹湖相砂岩层夹在薄泥岩层和透镜体中，发现类似满藻类的椭圆裂缝。这些裂缝被解释为由砂的液化和注入、泥浆的水塑性变形以及水饱和条件下沉积物的伴随脱水而形成的层内收缩裂缝。裂缝被认为是由地震和/或波浪引起的载荷形成的，并在蒙脱石被认为局部集中在泥浆中的地方开始。假设裂缝发展成椭圆轮廓，反映了干涉波纹槽的轮廓，这是由于沉积在波纹砂层上的两个薄泥层之间的渗透率差异。