黄河下游冰成滑塌与塌陷构造的研究

黄河是一条有着特殊水文、水动力、沉积环境及沉积物的河流。因此，它盛产特殊的沉积现象---冰成滑塌与塌陷构造便是其中之一。冰成滑塌与塌陷构造在黄河下游非常发育，它们主要发育在边、心滩上，有时天然堤上也有发育。它们的发育深刻地影响和改造了边、心滩的沉积景观。冰成滑塌构造是一种在沉积物从冰冻状态转向冰成状态发育的一种特殊构造，其运动学特点是以滑，即以水平运动为主，冰成滑塌构造多呈鳞片状或皱褶状。鳞片状者直径多在数十厘米；“鳞片”厚度多在十厘米左右，多由数个到十余个鳞片组成。其底界是冰冻界面；皱褶状者规模甚小，每一皱褶的宽度一般宽在一厘米以内，长十到二、三十厘 米，厚二、三厘米。多由数十个微型滑塌组合成一褶皱片。在天然堤内缘有一种特殊的冰成滑塌，它们使天然堤边缘呈阶步状或沟渠状，非常引人注目。冰成塌陷构造也是一种由冰层融化所形成的特殊构造，其运动学特点是“塌”，即以垂直运动为主。冰成塌陷构造多呈多角形坑洞状。直径多在数十厘米到一、二米，大者可达十余米，深度多在十余厘米。一般成群发育。

Study on the Ice-Induced Slump and Subsidence Structures in the Lower Course of Yellow River

The Yellow River is of special hydrology, hydodynamics, sedimentary environment and deposits, resulting in forming a lot of unusual sedimentary phenomina: one of them is ice-induced slump or subsidence structure. Ice-induced slump and subsidence structure are considerably common in the lower course of the Yellow River. They mainly develop in the point bar and/or channel bar, sometimes also in levee. Their development influences and remakes the sedimentary views of the point bar and channel bar. Ice-induced slump structure is an unusual structure that is formed in such a state that the sediment is transformed from the being frozen to being melt, and its motion is featured by sliding, mainly with horizontal motion. Those ice-induced structures developing in the point bar and/or channel bar are like scales or wrinkles. Those ones like scales composed by several to more than ten,are dozens of centimeters in diameters with the thickness of mostly ten of centimeters,and their bottom boundaries are frozen ones; and those ones like wrinkles are very small in size and each wrinkle is below one centimeter in width, ten to thirty centimeters in length and two or three centimeters in thickness. Sometimes, a specical ice-induced slump may be seen in levee and it makes the edge of levee look like steps or gullies. Also, the ice-induced subsidence structure is a kind of special structures formed by ice layer's melting and its motion feature is subsiding, mainly moving vertically. Ice-melt-induced subsidence structures have the multangylar shapes and look hole-like. Their diameters are mostly several tens of centimeters to one or two meters and the largest may amount to more than ten meters and the depth is more than ten centemeters. They often develop in groups.