内蒙古克什克腾旗经棚古湖形成与演化

发布时间：2018-03-08 00:10

本文选题：经棚古湖　切入点：典型湖相沉积剖面　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：克什克腾旗位于内蒙古自治区东部,地处大兴安岭西南端,属于半湿润与干旱半干旱气候分界线附近。本文以经棚古湖沉积物为研究对象,在前人的研究基础上,通过大量野外实地调查,利用沉积地层学、年代学及遥感地质学等多种方法,系统深入探讨克什克腾经棚古湖的形成与演化以及古湖演化与西拉木伦河演化的关系。主要取得以下认识:1.研究区位于西拉木伦河中上游水系发育,地形差异较大,河流阶地地貌发育。其干流和支流普遍发育5、6级阶地。阶地类型以基座阶地和堆积阶地为主,少数可见侵蚀阶地。不同河段阶地变化大,河谷地貌特征存在较大差异。2.综合分析湖相沉积剖面特征可知,经棚古湖沉积物连续分布于西拉木伦河上游两岸,在平面上呈树枝状分布,分布面积约232km2。湖相层分布的最高海拔在921~1120m之间,在不同河段形成不同程度沉积。3.根据测得的年代数据,结合前人的资料表明:经棚古湖相沉积的年龄在11~34ka之间,其时间跨度是从晚更新世晚期(Q_p~(3-3))至全新世早期(Qh1),中间淤积年龄约23千年。4.根据研究区地质地貌特征和典型沉积剖面特征分析,本文初步认为经棚古湖为一古堰塞湖。其成因可能是由于地震活动等原因引起山崩滑坡体或泥石流堵塞河床,使得西拉木伦河上游河水聚集形成湖泊。5.在经棚古湖演化过程中,构造运动、气候变化和水系变迁这三个因素均起到重要作用。
[Abstract]:Keshiketeng Banner is located in the eastern part of Inner Mongolia Autonomous region, located at the southwest end of the Daxingan Mountains, which belongs to the boundary between semi-humid and arid and semi-arid climates. Through a large number of field investigations, and by using various methods such as sedimentary stratigraphy, chronology and remote sensing geology, The formation and evolution of Keshiketeng through the ancient lake and the relationship between the evolution of the ancient lake and the evolution of the Xilamurun River are systematically discussed. The main conclusions are as follows: 1. The study area is located in the middle and upper reaches of the Xilamurun River, and the topography is quite different. The river terraces are developed. The main stream and tributaries generally develop 5 or 6 terraces. The terrace types are mainly pedestal terraces and accumulation terraces, and a few visible erosion terraces. The terraces of different river segments vary greatly. 2. Comprehensive analysis of the lacustrine sedimentary profile shows that the sediments distributed continuously in the upper banks of the Xilamurun River, and distributed in a dendritic shape on the plane. The distribution area is about 232km2. The maximum elevation of lacustrine facies distribution is between 921 ~ 1120m, and the sedimentary sediment of different extent is formed in different reaches. 3. Based on the dating data obtained and combined with previous data, it is shown that the sedimentary age of paleolacustrine facies is between 1134 ka and 1134 ka. Its time span is from late late Pleistocene to early Holocene QH1. The intermediate deposition age is about 23000.4.According to the geological and geomorphological characteristics of the study area and the characteristics of typical sedimentary profiles, In this paper, it is preliminarily considered that the ancient lake is an ancient barrier lake, which may be caused by landslide or debris flow caused by seismic activity, which makes the upper reaches of the Xilamurun River gather into a lake .5.In the course of the evolution of the ancient lake through the shed, Tectonic movement, climate change and water system change all play an important role.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P531

【相似文献】