阴山西段河流阶地发育的年代序列及其对构造隆升的指示意义

发布时间：2018-03-22 01:23

本文选题：阴山西段　切入点：构造隆升　出处：《地质学报》2017年01期 　论文类型：期刊论文

【摘要】：阴山位于河套断陷带北部,晚新生代以来,构造运动非常活跃,阴山持续不断隆起,河套随之不断下陷,作为地貌响应之一,阴山河谷中发育了一系列河流阶地。本文通过详细的野外地质调查,结合地貌学、沉积学及年代学方面的研究,厘定了阴山西段河谷普遍发育的4~5级河流阶地;并利用光释光(OSL)测年方法,恢复了其堆积-下切历史,建立了河流阶地年代框架:T4、T3、T2、T1级阶地大致形成时间分别为58.00ka BP、46.25ka BP、32.19ka BP、15.79ka BP之后;分析了本区河流阶地的成因:阴山的构造隆升为本区河流下切提供动力基础,是形成河流阶地的主要驱动力,气候变化通过改变水流流量与沉积物通量的比率影响阶地的堆积-下切行为的转换,是河流阶地形成的重要影响因素;进而利用河流侵蚀速率差异性讨论了晚更新世以来阴山西段的构造隆升模式:51.61~41.28ka BP之间,阴山西段隆升以中部高于东西部的穹窿式差异性隆升为主,23.22ka BP之后,阴山西段的隆升区段差异性减小,趋向于整体隆升。
[Abstract]:Yinshan is located in the north of the Hetao fault depression belt. Since the late Cenozoic, the tectonic movement has been very active, and the Yinshan mountain has been continuously rising, and the Hetao has been sinking continuously, which is one of the geomorphological responses. A series of river terraces have been developed in the Yinshan valley. Based on the detailed field geological survey and the study of geomorphology, sedimentology and chronology, we have determined the 4 or 5 grade river terraces that are generally developed in the western part of the Yinshan Mountains. By using the OSL dating method, the accumulation-down-cutting history of the terrace was restored, and the age frame of the river terrace: T4 (T4) T3 (T3) T2 + T1 terrace was approximately formed after 58.00ka BP46.25ka BP1 32.19ka BP1 15.79ka BP; The causes of formation of river terraces in this area are analyzed: the tectonic uplift of Yinshan provides the power base for the river cutting down in this area and is the main driving force for the formation of river terraces. Climate change is an important influence factor of river terrace formation by changing the ratio of flow flow to sediment flux. Furthermore, by using the difference of river erosion rate, the structural uplift model of the western Yinshan section since the late Pleistocene was discussed, between 51.61and 41.28ka BP, and after 23.22ka BP, the west part of Yinshan uplift was dominated by the dome uplift in the central part, which was higher than that in the eastern and western part. The difference of uplift section in the western part of Yinshan decreases and tends to the whole uplift.
【作者单位】：中国地质科学院地质力学研究所;中国地质大学(北京)地球科学与资源学院;
【基金】：中国地质调查局项目(编号:12120114042101)资助的成果
【分类号】：P931.1;P542

【相似文献】