内蒙古河套平原河流沉积相分析及其在第四纪地质调查中的应用
发布时间：2019-06-21 12:24
【摘要】：内蒙古河套盆地处于构造沉降区,第四纪以来河流沉积作用显著,沉积物保存完好,是研究沉积环境的良好区域。由于平原区地势平坦,受人类影响强烈,第四纪地质调查工作存在填图理论、方法、过程以及创新表达等方面的不足。地质工作者面临着填什么、怎么填、地质图件如何表达的棘手问题。通过遥感解译获取研究区表层地貌特征,应用浅钻揭露(槽型钻、冲击钻)获得浅层沉积物、沉积组合、沉积构造的原始资料。结合测年数据,确定不同期次河流的沉积亚相及沉积微相。将沉积相划分引入到第四纪地质调查工作,为其提供理论支撑和创新表达方法。经过以上研究得出以下认识:1、通过对不同深度钻孔中沉积物及沉积组合特征研究,结合测年数据依次确定全新世以来不同时期河流的河道亚相、堤坝亚相(天然堤微相)、泛滥平原亚相;建立了全新世以来河流沉积模式,为后期第四纪地质调查提供理论指导;通过对野外沉积相划分工作的总结,提出了研究区独有的沉积相判断标准,为第四纪地质调查工作中填图单元的确定提供了依据。2、通过对研究区钻孔FX1A和FX2A中样品进行光释光和14C年代测试,得到地下1-2 m深度处沉积物年龄值为3.920±0.03 ka;7.14-7.5 m深度处沉积物年龄值为7.99±0.29 ka;7.79-7.99 m深度处沉积物年龄值为10.79±0.73 ka。为沉积亚相和沉积微相的确定及填图工作的开展提供了精确的时间约束。3、通过遥感解译、路线地质调查、浅钻揭露(槽型钻、冲击钻)的手段,结合沉积相的划分确定了研究区1:50000第四纪地质图填图单元;采用“逐步逼近”原则确定地质界线并以“时代(地层)+成因+沉积相”作为填图单位的表达方式;将典型钻孔柱状图表达于相应沉积单元内,精确表达了地质体信息,并丰富了地质图内容。该方法为具有相似地质条件的平原区第四纪地质调查工作提供了示范,具有一定的推广价值。为不同成因类型的盆地区第四纪地质调查工作指出了新的方向。
[Abstract]:Hetao Basin in Inner Mongolia is located in the tectonic subsidence area. Since Quaternary, the fluvial sedimentation has been remarkable and the sediment is well preserved. It is a good area for the study of sedimentary environment. Because the plain area is flat and strongly influenced by human beings, there are some shortcomings in Quaternary geological survey, such as mapping theory, method, process and innovative expression. Geologists are faced with thorny questions about what to fill, how to fill it, and how to express geological maps. The surface geomorphological characteristics of the study area are obtained by remote sensing interpretation, and the original data of shallow sediment, sedimentary assemblage and sedimentary structure are obtained by shallow drilling exposure (trough drilling, impact drilling). Based on the dating data, the sedimentary subfacies and sedimentary microfacies of different stages of rivers are determined. The division of sedimentary facies is introduced into Quaternary geological survey to provide theoretical support and innovative expression method. Through the above research, the following understandings are obtained: 1. Through the study of the characteristics of sediments and sedimentary assemblages in different depths of drilling, combined with dating data, the river subfacies, dike subphase (natural embankment microphase) and flood plain subphase of rivers in different periods since Holocene are determined in turn, and the river sedimentary model since Holocene is established, which provides theoretical guidance for the late Quaternary geological survey. Based on the summary of the division of sedimentary facies in the field, the unique criteria for judging sedimentary facies in the study area are put forward, which provides the basis for the determination of the mapping unit in the Quaternary geological survey. 2. Through the photoluminescence and 14C dating tests of the samples in the drilling FX1A and FX2A in the study area, the age value of the sediment at the depth of 1 m and 2 m underground is 3.920 卤0.03 ka;. The sediment age value at 7.14 鈮，
本文编号：2504071
[Abstract]:Hetao Basin in Inner Mongolia is located in the tectonic subsidence area. Since Quaternary, the fluvial sedimentation has been remarkable and the sediment is well preserved. It is a good area for the study of sedimentary environment. Because the plain area is flat and strongly influenced by human beings, there are some shortcomings in Quaternary geological survey, such as mapping theory, method, process and innovative expression. Geologists are faced with thorny questions about what to fill, how to fill it, and how to express geological maps. The surface geomorphological characteristics of the study area are obtained by remote sensing interpretation, and the original data of shallow sediment, sedimentary assemblage and sedimentary structure are obtained by shallow drilling exposure (trough drilling, impact drilling). Based on the dating data, the sedimentary subfacies and sedimentary microfacies of different stages of rivers are determined. The division of sedimentary facies is introduced into Quaternary geological survey to provide theoretical support and innovative expression method. Through the above research, the following understandings are obtained: 1. Through the study of the characteristics of sediments and sedimentary assemblages in different depths of drilling, combined with dating data, the river subfacies, dike subphase (natural embankment microphase) and flood plain subphase of rivers in different periods since Holocene are determined in turn, and the river sedimentary model since Holocene is established, which provides theoretical guidance for the late Quaternary geological survey. Based on the summary of the division of sedimentary facies in the field, the unique criteria for judging sedimentary facies in the study area are put forward, which provides the basis for the determination of the mapping unit in the Quaternary geological survey. 2. Through the photoluminescence and 14C dating tests of the samples in the drilling FX1A and FX2A in the study area, the age value of the sediment at the depth of 1 m and 2 m underground is 3.920 卤0.03 ka;. The sediment age value at 7.14 鈮，
本文编号：2504071
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