宁武—静乐盆地中生代沉积—构造演化及其后期改造研究

发布时间：2018-04-12 13:47

本文选题：宁武—静乐盆地 + 中生代　；参考：《太原理工大学》2017年硕士论文

【摘要】：宁武—静乐盆地在大地构造上处于比较特殊的地理位置,其东侧为太行山板内造山带,东北部紧靠燕山板内造山带的南端,北部与华北北缘板内活动带相距不过百余公里,西侧为华北克拉通稳定地块鄂尔多斯盆地,西南侧紧邻吕梁山隆起带。本文以宁静盆地中生界砂岩为主要研究对象,探讨砂岩骨架颗粒基本特征及其母岩组合,分析物源区位置及其构造背景。在此基础上,结合前人的研究成果,分析了宁武—静乐盆地中生代的沉积与构造演化和后期改造,对进一步研究晋西北中生代以来的陆壳演化史,具有重要的意义。主要得出以下认识:1、宁静盆地中生代沉积了一套河湖相碎屑岩建造。刘家沟组及和尚沟组中以长石岩屑砂岩与岩屑长石砂岩为主,二马营组、铜川组及延长组中以磨圆度和分选性更好的长石/岩屑石英砂岩为主,永定庄组及大同组下部砂岩主要以长石/岩屑石英砂岩、石英砂岩为主,侏罗系的其他层位的砂岩以岩屑长石砂岩与长石岩屑砂岩为主,在天池河组中含有凝灰质砂岩。2、中生代陆源剥蚀区位于宁静盆地北侧的阴山、燕山一带,由先期侵入的花岗质岩石、古老变质岩和沉积盖层组成,具有混源特征,在晚三叠世及中侏罗世晚期,陆源剥蚀区古老变质岩的出露面积更加广泛,具有逐渐扩大的趋势,相对而言,沉积盖层的出露面积逐渐变小。阴山燕山造山带一直处于陆内隆升的构造背景,长期稳定的为宁静盆地提供碎屑物源。3、宁武—静乐盆地的早中三叠统地层是在二叠系沉积盆地上的继承和发展的,并延续了北高南低的构造格局;在晚三叠世形成了继承性坳陷盆地,并在沉积延长组之后,盆地处于隆升剥蚀状态;早侏罗世晚期华北东部在伸展构造机制下致使云岗、宁武一带形成短轴山间断陷盆地,开始沉积永定庄组;大同组沉积时期延续了早侏罗世晚期拉张的构造背景,湖盆沉积范围相应的扩大;云岗组连续沉积在大同组之上,构造环境由伸展构造背景转变成挤压构造背景;在沉积了云岗组之后,湿润的气候快速转变为干燥的强氧化气候,沉积了天池河组。4、晚侏罗世至早白垩世早期,宁静盆地受挤压作用影响,整体隆升,地势高低不平,在长期风化作用过程高地遭受剥蚀,宁静盆地处于准平原化阶段;晚白垩世,盆地受到了北西—南东向的挤压作用,形成北东—南西向展布的小型复向斜盆地;宁静盆地自古近纪以来,进入强烈隆升阶段,盆地在中新世晚期与周边吕梁山北段地区存在明显的差异隆升,最终形成如今地貌。
[Abstract]:The Ningwu-Jingle basin is located in a relatively special geographical position on the tectonic structure. The eastern side of the basin is the Taihang mountain intraplate orogenic belt. The northeast is close to the southern end of the Yanshanian intraplate orogenic belt, and the northern part of the basin is no more than 100 kilometers apart from the northern margin of North China.To the west is the Ordos basin of the North China Craton stable block, and the southwest side is adjacent to the Luliangshan uplift.Taking Mesozoic sandstone of Xijing Basin as the main research object, this paper discusses the basic characteristics of sandstone skeleton grain and its parent rock assemblage, and analyzes the location of source area and its tectonic background.On this basis, combined with the previous research results, the sedimentary and tectonic evolution and late reformation of Mesozoic in Ningwu-Jingle basin are analyzed, which is of great significance to further study the history of continental crust evolution since Mesozoic in northwestern Shanxi.The main conclusions are as follows: 1: 1, a set of fluvial and lacustrine clastic rock formations were deposited in the quiet basin during the Mesozoic.The feldspathic sandstone and lithic feldspar sandstone are dominant in the Liujiagou formation and the Shengou formation, and the feldspar / lithic quartz sandstone with better grinding roundness and better sorting in Ermaying formation, Tongchuan formation and Yanchang formation.The lower sandstone of Yongdingzhuang formation and Datong formation are mainly feldspar / lithic quartz sandstone, quartz sandstone, and other Jurassic sandstone are lithic feldspathic sandstone and feldspathic lithic sandstone.There is tuffaceous sandstone. 2 in Tianchihe formation. The Mesozoic continental denudation area is located in the Yinshan and Yanshanian areas in the northern side of the quiet basin. It is composed of pre-intrusive granitic rocks, ancient metamorphic rocks and sedimentary caprocks, and is characterized by mixed source.In the late Triassic and the late Middle Jurassic, the exposed area of the ancient metamorphic rocks in the continental source denudation area is more extensive and has a trend of gradual expansion, relatively speaking, the exposed area of the sedimentary caprock gradually becomes smaller.The Yinshan Yanshanian orogenic belt has always been in the tectonic setting of intracontinental uplift, providing the source of clastic material for the quiet basin steadily for a long time. The early and middle Triassic strata of the Ningwu-Jingle basin were inherited and developed on the Permian sedimentary basin.The succession depression basin was formed in the late Triassic, and the basin was uplift and denuded after the sedimentary Yanchang formation, and Yungang was caused by the extensional structure in the eastern part of North China in the late early Jurassic.The lacustrine basin was formed in Ningwu area and began to deposit Yongdingzhuang formation. The sedimentary period of Datong formation continued the extension of tectonic setting of late early Jurassic, and the sedimentary range of lake basin was enlarged accordingly, and Yungang formation was continuously deposited on Datong formation.The tectonic environment changed from extensional tectonic setting to compressional tectonic setting, after the Yungang formation was deposited, the humid climate changed rapidly into a dry strong oxidized climate, and the Tianchihe formation. 4. Late Jurassic to early Cretaceous, the late Jurassic to the early Cretaceous, late Jurassic to early Cretaceous.The quiet basin is affected by compressional action, the whole uplift, the topography is uneven, the highlands are denudated during the long-term weathering process, the quiet basin is in the quasi-plain stage, and the basin was squeezed by the NW-SE direction in the late Cretaceous.Since Paleogene, the quiet basin has entered a strong uplift stage, and there are obvious differences in uplift between the basin in the late Miocene and the northern segment of Luliangshan in the surrounding area, resulting in the formation of the present geomorphology.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P548

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