鄂尔多斯盆地下白垩统大型类碟状构造的发现及其地质意义

发布时间：2018-03-16 23:27

本文选题：类碟状构造　切入点：软沉积物变形构造　出处：《古地理学报》2017年01期 　论文类型：期刊论文

【摘要】：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。
[Abstract]:A special soft sediment deformation structure was found in the Lower Cretaceous in the northern Ordos Basin, which is very similar to the disc structure. It is mainly exposed in the outcrop section on both sides of the 100km long highway from Ordos City to Hangjin Banner section of G109 State Road. The soft sedimentary deformation structure is a set of yellowish brown or grayish white conglomerate or sandy gravel of lower Cretaceous. The edges of the vertical plane are raised, the middle is flat or concave, Therefore, the author calls it "disc-like structure". The disc-like structure is characterized by a large scale. The width of the small person is generally 1 ~ 3 m, the height is 0.5 ~ 1.5 m, the width of the large person is generally 5 ~ 6 m, the maximum is 10 m, the height is 1 ~ 1. 5 m, and a few can reach a few. 2) the degree of warping on both sides is different, Including inclined edges with dip angles less than 45 degrees, steep sloping edges with dip angles between 45 degrees and 75 degrees, near vertical edges with dip angles between 75 degrees and 90 degrees and roll edges with dip angles greater than 90 degrees. On the vertical plane, most of them are funnel-shaped and inverted triangular-shaped, and the dominant orientation of the gravelly long axis on the edge of the disk-shaped structure is parallel to the direction of flow deformation. The disk-like structure is often associated with the sandstone vein and the liquefied vein. The bottom of soft deformation bedding or soft deformation fold etc., symbiotic. 6) the bottom is mostly lacustrine brown red (sometimes slightly grayish) mudstone or sandy mudstone, which, because of liquefaction flow, is more massive and easily broken. According to the above characteristics, It is considered that the mud discharge formed in the disk-like tectonic system is caused by strong earthquake disturbance, and the earthquake intensity can reach M = 8 or even M = 9 ~ 10. The earthquake activity may be related to the strong Mesozoic tectonic movement in the northern part of the Ordos Basin.
【作者单位】：中国石油大学(华东)地球科学与技术学院;
【基金】：国家自然科学基金项目(编号:41572088)资助~~
【分类号】：P552;P534.53

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