丹东地区辽吉裂谷的深部地质结构及三维地质模型

发布时间：2018-07-02 10:07

本文选题：辽吉裂谷 + 龙岗地块　；参考：《吉林大学》2016年博士论文

【摘要】：三维地质调查或三维地质填图作为一项综合性、前沿性的区域地质调查工作,旨在借助地表地质填图、综合地球物理测深、钻探、三维可视化等技术和手段,研究地质体在三维空间上的展布特点及其相互关系,揭示深部地质结构、深部地质作用对矿产分布、地质环境等的制约关系,为解决重大地质问题、深部矿产预测、重大地质灾害预测、地下工程的地基稳定性评价等提供依据。三维地质建模技术作为三维地质调查的基础和核心问题,已经成为国内外地质、矿业等领域研究的热点。研究区位于辽宁省东部的丹东市北部地区,处于华北克拉通东部陆块北部的古元古代构造带-辽吉裂谷中,是我国前寒武纪地质研究较为典型的地区,同时也是辽东-吉南成矿带重要的成矿单元。辽吉裂谷带内分布有厚度达万米的古元古代辽河群和裂谷不同演化阶段的岩浆岩,该带内矿产资源较为丰富,主要矿产为金、银、铅、锌、菱镁矿、滑石、硼、钴、铜、铁等,这些不同类型的矿床在辽河群的分布呈现一定的层控性,硼矿主要赋存在里尔峪组中,石墨矿产于高家峪组中,而菱镁矿、铅锌矿、金银矿则主要赋存在大石桥组中。前人针对包括研究区在内的辽东地区的华北克拉通形成与演化、胶-辽-吉古元古代活动带的构造属性、古元古代沉积建造的划分与对比、辽河群主要类型矿床的形成机理及深部找矿潜力、中生代构造岩浆活动与成矿等重大地质及找矿等问题,通过地质、地球化学、同位素年代学、地球物理等方法开展了大量的研究工作,并积累了大量的基础地质资料和找矿成果。但这些研究成果主要基于地表地质调查工作,一些重大地质理论问题如辽吉裂谷带的构造属性及演化、古元古代花岗岩的成因、辽河群的形成及演化、凤城青城子矿集区铅、锌、金、银矿、翁泉沟等地的硼矿的成因等研究目前仍然争论较大,同时,辽吉裂谷带深部结构特征、基底性质及其组成等三维尺度的地质地球物理等综合研究较少,从某种程度上也制约了人们对研究区一些重大地质和成矿问题的认识。论文中国地质调查局下达的“本溪-临江地区深部地质调查”项目为依托,以1∶25万丹东幅区域地质调查资料和1∶20万区域地球物理资料为基础,通过对六条实测的高精度重力、高精度地面磁法、大地电磁测深等非震地球物理剖面资料处理与解释,采用重磁资料延拓、重磁剖面联合反演、三维密度反演等技术方法,揭示了研究区的主要地质界面、断裂构造、中生代盆地、侵入岩体等深部地质结构特征,加深了对研究区深部地质结构的认识;采用多级剖面控制、分单元的三维地质建模方法,基于Go CAD三维建模软件,初步构建了研究区主要地质单元的三维地质模型,为了解该区的主要目标地质体-辽河群等的空间展布特征、辽吉活动带的基底性质及其可能组成,揭示区域地质构造背景、深部地质过程与成矿作用的耦合关系,在三维尺度上为辽吉活动带的构造环境及演化等重大地质问题解决和深部矿产资源潜力预测等提供科学依据。论文获得的主要成果和认识如下:1、确定了龙岗地块与辽吉裂谷的构造分界线,该分界线位于双塔岭-三道岭-连山关一线,为一条具有正断层性质的断裂带,该断裂带对研究区的岩浆活动、沉积作用、矿产资源分布具有重要的控制作用,也进一步证明了辽吉构造带具有裂谷性质。2、辽吉花岗岩具有低密度、磁性弱的特点,辽吉花岗岩、辽河群的微量元素、稀土元素配分模式与太古宙地质体较为相似,结合辽吉花岗岩、辽河群中碎屑锆石记录的多期太古宙地质作用的年龄信息,得出辽吉花岗岩、辽河群的源区主要为太古宙结晶基底。3、辽吉裂谷是在太古宙结晶基底的基础上形成的,其基底组成在不同的构造部位则不尽相同,在研究区的北部地区主要由晚太古代深成侵入体及小规模表壳岩组成,而在中部地区主要由辽吉花岗岩组成。4、中生代小型火山沉积盆地主要沿NE向断裂构造发育,控盆边界断裂具有正断层性质,是由中生代走滑拉伸作用形成的,盆地边界后期遭受挤压改造。5、确定了主要中生代侵入岩体的深部地质结构与三维几何形态。发现在青城子镇-通远堡镇、岫岩地区的深部存在着对成矿有重要影响的中生代隐伏岩体,而辽河群之下存在中生代隐伏花岗侵入岩体的地段为有利的成矿地段,主要包括岫岩地区的韩家岭岩体及青城子地区的双顶沟岩体的隐伏区。6、构建了重点地区的三维地质模型,实现了丹东地区辽吉裂谷5km以浅深度范围的地质结构透明化,以三维可视化的形式展示了辽河群主要地质界面、主要断裂、主要侵入岩体、中生代盆地的三维几何特征,并对隆昌-通远堡-草河口及岫岩重点区的三维地质特征进行了详细解释。上述研究成果为辽吉裂谷带构造属性及演化、深部矿产远景预测等重大地质理论问题的解决提供了新的证据,同时,论文中所采用的三维地质调查流程、深部地质结构研究方法和三维地质建模方法将为其他的相关研究提供借鉴。
[Abstract]:Three dimensional geological survey or three-dimensional geological mapping, as a comprehensive, frontier regional geological survey, aims to study the distribution characteristics and relations of geological bodies in three-dimensional space by means of surface geological mapping, comprehensive geophysical sounding, drilling, and three-dimensional visualization, to reveal the deep geological structure and deep geology. The restrictive relation between the mineral distribution and the geological environment is provided for the solution of major geological problems, the prediction of the deep mineral resources, the prediction of the major geological disasters and the evaluation of the foundation stability of the underground engineering. As the foundation and core of the three-dimensional geological survey, the 3D geological modeling technology has become a research field in the geology and mining industry at home and abroad. The research area, located in the northern part of Dandong City, east of Liaoning Province, is located in the Paleoproterozoic tectonic belt of the northern part of the eastern North China Craton - Liaoji rift valley. It is a typical area in the study of the Precambrian Geology in China, and is also an important metallogenic unit in the Liaodong - Zilan metallogenic belt. The Palaeoproterozoic Liaohe Group and the magmatic rocks of different evolution stages of the rift valley are rich in mineral resources. The main minerals are gold, silver, lead, zinc, magnesite, talcum, boron, cobalt, copper and iron. The distribution of these different types of deposits in the Liaohe Group is a certain layer control, and the main boron deposits are in the Lille Valley, and the graphite mineral is in the Guyu valley. The formation and evolution of the North China Craton in Liaodong area, including the study area, the formation and evolution of the North China Craton in the area of the study area, the tectonic attributes of the Proterozoic and Paleoproterozoic sedimentary formations, the division and comparison of the Paleoproterozoic sedimentary formations, the formation mechanism and the deep part of the main types of the Liaohe Group are found in the formation and evolution of the Dashiqiao craton in the Liaodong area, including the study area. The potential of ore prospecting, Mesozoic tectonic magmatism and mineralization and other major geological and prospecting problems have been carried out in a large amount of research through geology, geochemistry, isotopic chronology and Geophysics, and a large amount of basic geological data and prospecting results have been accumulated, but some of these research results are mainly based on the surface geological survey. Major geological theories, such as the tectonic properties and evolution of the Liaoji Rift Valley, the formation and evolution of the Palaeoproterozoic granites, the formation and evolution of the Liaohe Group, the genesis of boron deposits in the lead, zinc, gold, silver and Weng Quan gullies in the Qingcheng Zenzi mining area, Fengcheng, are still controversial, and the deep structural features, basement properties and their groups in the Liaoji rift zone are in the same time. The comprehensive study of geophysical and Geophysics, such as the three dimensional scale, has limited people's understanding of some major geological and metallogenic problems in the study area. This paper is supported by the project of "Benxi - Linjiang deep geological survey" by the China Geological Survey Bureau, with the 1: 250 thousand Dandong regional geological survey data and 1: 200 thousand on the basis of regional geophysical data, by processing and interpreting the non earthquake geophysical profile data of six measured high precision gravity, high precision ground magnetic method and magnetotelluric sounding, the main geological interface and fracture of the study area are revealed by the techniques of gravity and magnetic data extension, joint inversion of gravity and magnetic profiles and three-dimensional density inversion. The structure, Mesozoic basin, intrusion of rock mass and other deep geological structures have deepened the understanding of the deep geological structure of the study area, and the three dimensional geological modeling method based on the multilevel section control and the division of the unit, based on the Go CAD 3D modeling software, initially constructed the three-dimensional geological model of the main geological unit in the study area, in order to understand the main target of this area. The spatial distribution characteristics of the geological body and the Liaohe Group, the basement properties of the Liaoji active belt and its possible composition, reveal the regional geological structure background, the coupling relationship between the deep geological process and the mineralization, and the solution of the tectonic environment and evolution of the Liaoji active belt and the prediction of the potential of the deep mineral resources on the three-dimensional scale. The main achievements and understanding of the paper are as follows: 1, the boundary between the Longgang massif and the Liaoji Rift Valley is determined. The boundary line is located in the Ling - three Dao Ling - Lianshan Guan line of the Twin Towers. It is a fault zone with normal fault properties. The fault zone is important to the rock slurry activity, sedimentation and mineral resources distribution in the study area. The control effect has further proved that the Liaoji tectonic belt has the Rift Valley Property.2, the Liaoji granite is characterized by low density and weak magnetism, the trace elements of Liaoji granite and Liaohe Group, the distribution pattern of the rare earth elements are similar to the Archean geological bodies, and the Liaoji granites are combined with the Liaoji granites, and the detrital zircons recorded in the Liaohe Group are mostly Archean geology. The source area of Liaoji granite is obtained by age information. The source area of Liaohe Group is mainly the Archean crystalline basement.3, and the Liaoji Rift Valley is formed on the basis of the Archean crystalline basement. The basement of the Liaoji rift is not the same in different tectonic sites. In the northern area of the study area, it is mainly composed of late Archean deep formation intrusive body and small scale case rock. The central region is mainly composed of Liaoji granite.4, the Mesozoic small volcanic sedimentary basin mainly develops along the NE fault structure, the basin boundary fault has the nature of normal fault, it is formed by the Mesozoic strike slip stretching effect, and the late boundary of the basin has been squeezed and transformed by.5, and the deep geological structure of the main Mesozoic intrusive rocks is determined. It is found that in the deep part of Xiuyan area in Qingcheng Town, Tong Yuan Town, there is a Mesozoic concealed rock mass which has an important influence on the mineralization, while the area of the Mesozoic concealed granite intrusion under the Liaohe Group is a favorable metallogenic area, mainly including the Han Jialing rock in Xiuyan and the double trench rock in the Qingcheng area. The hidden area.6 of the body has constructed the three-dimensional geological model of the key area, and realized the transparency of the geological structure of the Liaoji Rift Valley in Dandong area with the shallow depth range, showing the main geological interfaces of the Liaohe Group in the form of three-dimensional visualization, the main fracture, the main intrusion of rock mass, the three-dimensional geometric features of the Mesozoic basin, and the Longchang Tong Yuan fort - grass The three dimensional geological characteristics of the key areas of the estuarine and Xiuyan are explained in detail. The above results provide new evidence for the structural properties and evolution of the Liaoji Rift Valley, the prediction of the deep mineral distance prediction and other major geological theory problems. At the same time, the three-dimensional geological survey process, the deep geological structure research method and the three-dimensional method used in the paper are used. The method of geological modeling will provide reference for other related research.
【学位授予单位】：吉林大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P548

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