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在鄂尔多斯盆地北部下白垩统中发现一种特殊的软沉积物变形构造,其与碟状构造非常相似,主要出露于G109国道鄂尔多斯市至杭锦旗段100余千米长的公路两侧的露头剖面中。该类软沉积变形构造岩性为下白垩统的一套黄褐色或灰白色的中厚层砾岩或砂砾岩,在竖直面上其边缘翘起、中部平坦或下凹,故笔者把它称之为“类碟状构造”。类碟状构造特征为:(1)规模总体很大。小型者的宽度一般为1~3m,高度多为0.5~1.5m;大型者的宽度一般为5~6m、最大可近10m,高度多为1~1.5m、少数可达2m;(2)两侧翘起程度不同,包括倾角小于45°的倾斜边、倾角在45°~75°之间的陡斜边、倾角在75°~90°之间的近直立边和倾角大于90°的翻卷边;(3)类碟状构造之间为泄水形成的液化充填体,竖直面上多呈漏斗形和倒三角形;(4)类碟状构造边缘的砾石长轴优势排列方位平行于流动变形方向;(5)类碟状构造常与砂岩岩脉、液化脉、软变形层理或软变形褶皱等共生。(6)底部多为湖相棕红色(有时夹少量灰色)泥岩或砂质泥岩,其由于液化流动而多呈块状,极易破碎。根据上述特征,认为类碟状构造系泥泄水形成的,是受强烈地震扰动所致,地震强度可达8级、甚至9~10级。该地震活动可能与鄂尔多斯盆地北部中生代强烈的构造运动有关。
A special soft-sediment deformation structure is found in the Lower Cretaceous of the Ordos Basin. It is very similar to the saucer-shaped structure. It is mainly exposed on the outcrops on both sides of the highway more than 100 km long from Erdos to Hangjin Banner of the G109 National Highway Section. This type of soft sedimentary deformation of lithology is a set of Lower Cretaceous khaki or gray white conglomerate or glutenite, the edge of the vertical tilt, the central flat or concave, so I call it The “class disc structure ”. Class disc structural features are: (1) the scale of the overall large. The width of small people is generally 1 ~ 3m, the height is mostly 0.5 ~ 1.5m; the width of large people is generally 5 ~ 6m, the maximum can be nearly 10m, the height is mostly 1 ~ 1.5m, a few can reach 2m; The degree of side lift is different, including beveled edges with an inclination less than 45 °, steep bevels with an inclination between 45 ° and 75 °, near vertical edges with an inclination between 75 ° and 90 °, and curled edges with an inclination greater than 90 ° ; (3) liquefaction filling bodies formed by drainage between the saucer-like structures are mostly funnel-shaped and inverted triangle on the vertical surface; (4) the predominant orientation of the gravel long axis along the edge of the saucer-shaped structure is parallel to the flow deformation (5) The discoid structure is often associated with sandstone dikes, liquefaction veins, soft deformation bedding or soft deformation folds. (6) Most of the bottom of the lake brown reddish brown (sometimes with a small amount of gray) mudstone or sandy mudstone, due to liquefaction flow and more massive, easily broken. According to the above characteristics, it is considered that the catastrophic disc-like structure formed by muddy discharge is caused by the strong earthquake disturbance, and the earthquake intensity can reach 8 or even 9-10. The seismic activity may be related to the strong tectonic movement of the Mesozoic in the northern Ordos Basin.