宽甸—桓仁地区辽吉裂谷深部地质结构及三维地质模型

发布时间：2018-07-12 17:42

  本文选题：宽甸-桓仁 + 辽吉裂谷　； 参考：《吉林大学》2016年博士论文

【摘要】：近年来,随着我国经济飞速发展,消耗了大量的矿产资源,尤其是浅部的矿产资源已开采殆尽,为了保持我国经济的增长势头,亟需解决资源短缺的问题,因此深部找矿已渐渐成为资源勘查的重点。辽吉裂谷带作为我国重要的成矿构造带,具有漫长复杂的演化历史,具有优越的深部成矿条件,因此,研究辽吉裂谷的深部地质结构对加深华北克拉通的地质特征认识和寻找深部矿产资源具有十分重要的意义。前人对于辽吉裂谷的研究主要集中于地表地质研究,缺乏对深部地质结构的认识,这在很大程度上制约了对辽吉裂谷地质特征的全面了解和深部成矿远景预测。此次针对宽甸-桓仁(包括辽宁省宽甸县、本溪县、桓仁县,及吉林省集安市西部)地区的辽吉裂谷深部地质结构做了系统研究。笔者以前人的研究成果为基础,以地质与非震地球物理分析相结合为手段,收集了研究区以往的地质资料,处理并分析了区域重力、航磁及实测非震地球物理剖面(高精度重力-高精度地磁-MT组合)等数据,结合岩石物性参数对辽吉裂谷的深部地质结构进行了揭示。建立了辽吉裂谷及龙岗地块的深部地质格架,确定了龙岗地块与辽吉裂谷之间构造边界的具体位置,进一步加深了对于辽吉裂谷演化历史的认识,探讨了辽吉裂谷的基底结构与组成,揭示了辽吉裂谷内部主要地层单元、岩体、断裂的三维空间展布和几何形态,建立了宽甸-桓仁地区的三维地质模型。论文的主要内容如下:(1)在研究区内10条主干剖面的重力反演解释及同坐标的10条实测非震地球物理剖面的处理解释基础上,建立了研究区内辽吉裂谷和龙岗地块的深部地质格架。龙岗地块具有太古宙结晶基底与新元古界-古生界沉积盖层双层结构,辽吉裂谷内的岩石建造遭受强烈褶皱;在靠近辽吉裂谷与龙岗地块的构造边界的地区、辽河群之下为太古宙结晶基底,在辽吉裂谷的中部地区辽河群之下发育古元古代辽吉花岗岩。(2)利用重力、航磁异常切片图组合特征,结合区域地质资料,揭示了研究区的深部地质结构特征。宽甸-桓仁地区燕山期花岗质岩体分布广泛,并且在深部具有连片扩大趋势。鞍山地区存在“m”型重磁异常分布特征,结合区域地质资料,推测这种特殊异常分布特征是由于太古代含铁建造的褶皱所引起。(3)欧拉反褶积法对重力和磁法数据进行处理,获得了研究区内的主要构造线的延伸深度及倾向,通过与区域地质资料的对比,发现这些构造线与研究区主要断裂和岩体的边界相吻合,如八里甸子岩体的边界、寒岭-偏岭断裂、太平哨断裂及二户来断裂等;发现宽甸东部的白垩纪花岗岩体在深部有连片扩大趋势。(4)采用了非震地球物理资料及处理结果,根据龙岗地块与辽吉裂谷的物性差异,结合已有地质资料,厘清了辽吉裂谷与龙岗地块的构造边界的水平分布及地下展布,揭示了边界两侧不同深度地质体的属性特征。研究表明,辽吉裂谷形成之初,发育了一个控盆边界断裂,此断裂构成了龙岗地块与辽吉裂谷的原始构造边界,该构造边界是沿双塔岭、三道岭、连山关、大王沟、八里甸子、二户来、拐磨子等地,近东西向分布。该控盆边界断裂具有正断层性质,后期遭受了强烈改造,如发育了中生代断陷盆地及大规模早白垩世岩浆侵入等。(5)从深部地质的角度加深了辽吉裂谷构造演化过程的认识。太古宙龙岗地块和狼林地块源于同一个微陆块,经历了古元古代的裂谷作用之后,开始不断拉伸,并且在裂谷东部有海洋形成,最后又经历了一次双向的俯冲(在龙岗地块一侧向北俯冲,在狼林地块一侧向南俯冲),最终挤压造山,形成了辽吉裂谷构造带。(6)通过宽甸、桓仁及集安西部地区三维地质模型的建立,确定了以下深部地质结构:1宽甸地区辽河群底界埋深变化较大,从南到北,深部逐渐增大。红石、大西岔埋深小于1000m,太平哨、步达远及下露河平均埋深大于4000m,步达远以北中生代盆地处埋深可达7200m,二户来和集安西部地区埋深约为8000m;2宽甸地区的呈紧闭线型褶皱的辽河群的底界埋深小于2000m,该区经历了强烈挤压抬升,相当于辽吉裂谷深部变形的产物;3发现赛马碱性岩体底界埋深较浅,表明遭受了强烈剥蚀;4推测位于平顶山镇、大四平镇附近的复杂褶皱是由一个完整的向斜经多期断裂改造形成;5揭示出长甸岩体在深部具有较大分布范围,长甸岩体为上部宽下部窄的柱状体,该岩体西部在地下的规模较大,密度较低,推测主要为石英二长岩,岩体向东有一个分支,该岩体的底部最大埋深可达约7km。
[Abstract]:In recent years, with the rapid economic development of our country, a lot of mineral resources have been consumed, especially the mineral resources in the shallow part have been exhausted. In order to keep the economic growth of our country, it is urgent to solve the problem of resource shortage, so the deep prospecting has gradually become a heavy point of resource exploration. It has a long and complicated evolutionary history and has a superior deep metallogenic condition. Therefore, it is of great significance to study the deep geological structure of the Liaoji Rift Valley to deepen the understanding of the geological characteristics of the North China Craton and to find the deep mineral resources. The understanding of the qualitative structure has greatly restricted the comprehensive understanding of the geological features of the Liaoji Rift Valley and the prediction of the deep metallogenic prospect. This is a systematic study of the deep geological structure of the Liaoji Rift Valley in Kuandian - Huanren (including Kuandian, Benxi, Huanren, and the west of Ji'an, Jilin). On the basis of the results, the geological data of the study area have been collected by combining geological and non earthquake geophysical analysis. The data of regional gravity, aeromagnetic and measured non earthquake geophysical profiles (high precision gravity high precision geomagnetic -MT combination) are processed and analyzed. The geological structure of the deep geological structure of the Liaoji Rift Valley is combined with the physical parameters of the rock. The deep geological framework of the Liaoji Rift Valley and Longgang massif has been established. The specific location of the tectonic boundary between the Longgang massif and the Liaoji Rift Valley is determined, and the understanding of the evolution history of the Liaoji Rift Valley is further deepened, the basement structure and composition of the Liaoji rift valley are discussed, and the main stratigraphic units and rock masses in the Liaoji rift valley are revealed. Three dimensional geological models of Kuandian Huanren region are established. The main contents of this paper are as follows: (1) on the basis of the interpretation of gravity inversion of 10 main sections in the study area and the processing and interpretation of 10 measured non earthquake geophysical profiles in the same coordinates, the Liaoji Rift Valley and the Longgang land in the study area are established. The Longgang massif has a double structure of the Archean crystalline basement and the Neoproterozoic Paleozoic sedimentary cover, and the rock formation in the Liaoji Rift Valley is strongly folded; the Liao River group is the Archean crystalline basement near the Liaoji Rift Valley and the Longgang massif, and in the middle of the Liaoji Rift Valley, the Liao River is in the middle of the Liaoji rift valley. The Paleoproterozoic Liaoji granites are developed below the river group. (2) the deep geological structure of the study area is revealed by combining the characteristics of gravity and aeromagnetic anomaly slices, combining with the regional geological data. The Yanshan period granitic rock mass in Kuandian Huanren area is widely distributed and has the trend of enlargement in the deep part. The "m" type gravity and magnetic field exists in Anshan area. The anomalous distribution features, combining with the regional geological data, speculated that the special anomaly distribution was caused by the folds of Archean iron bearing formation. (3) the Euler deconvolution method was used to deal with gravity and magnetic data, and the extension depth and tendency of the main tectonic lines in the study area were obtained. By comparing with the regional geological data, it was found that Some tectonic lines are consistent with the boundary of main faults and rock masses in the study area, such as the boundary of the eight Li Dian Zi rock mass, the cold ridge - Yanling fault, the Taiping sentinel fault and the two - Household fault. It is found that the Cretaceous granite body in the east of Kuandian has the trend of enlargement in the deep section. (4) the data of non earthquake geophysical data and processing results are used, according to the Longgang massif and the The physical difference of the Liaoji Rift Valley, combining with the existing geological data, clarifies the horizontal distribution and underground distribution of the tectonic boundary between the Liaoji Rift Valley and the Longgang massif, and reveals the properties of the geological bodies of different depths on both sides of the border. The tectonic boundary of the Liaoji Rift Valley is along the Twin Towers ridge, three Dacheng mountains, Lianshan Guan, dwang Gou, eight Li Dian Zi, two households and abduction ground, and near East-West distribution. The boundary fault of the control basin has the nature of normal fault, and the later period suffered strong transformation, such as the Mesozoic faulted basin and the large-scale Early Cretaceous intrusion of magma. (5 The Archean Longgang massif and the wolf forest block originated from the same micro continental block, and after the Paleoproterozoic rift, the Archean and the wolf forest blocks began to stretch continuously and formed the ocean in the east of the rift valley, and finally experienced a two-way subduction (in the side of the Longgang massif). The North subduction, subducted on one side of the wolf forest block, eventually squeezed orogeny, formed the Liaoji Rift Valley structural belt. (6) through the establishment of three dimensional geological model in Kuandian, Huanren and the west of Ji'an, the following deep geological structure was established: 1 the depth and depth of the bottom of the Liaohe Group in the Kuandian area became larger and larger, from south to north, and gradually increased in the deep. The red stone and the big west fork were buried. The depth of deep less than 1000m, Taiping Shao, step Da Yuan and shinu river is more than 4000m, and the depth of buried depth of Mesozoic basin in north of Ji'an is up to 7200m, and the depth of buried depth in Western Ji'an is about 8000m, and the buried depth of Liaohe Group in the 2 Kuandian area is less than 2000m, and the region has experienced strong extrusion and uplift, which is equivalent to Liaoji fissure. 3 it is found that the buried depth of the base rock in the base rock of the horse is shallow, indicating strong denudation, and 4 speculated that the complex folds near the town of Pingdingshan and the town of the Siping town were formed by a complete syncline and multistage fracture, and 5 revealed that the long meadow rock has a larger distribution in the depth, and the meadow rock mass is the lower part of the upper part. In the west of the rock mass, the rock mass is large and low in density. It is presumed to be mainly quartz two long rock, and the rock mass has a branch eastward. The maximum depth of the rock bottom can reach about 7km..
【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】：P542
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本文编号：2117976