内蒙古中部乌拉山岩群岩石地球化学特征和原岩建造

发布时间：2018-04-15 02:27

本文选题：原岩建造 + 岩石地球化学特征　；参考：《东华理工大学》2017年硕士论文

【摘要】：早期古大陆的重建、早期大陆地壳的性质和演化已成为现代地球科学的重要前沿课程之一(范志伟,2013)。而乌拉山岩群处于地壳发展早期高级变质地区,其特征和成因的研究对查明该地区早期地壳形成和演化过程,具有重要的科学意义。论文依托“内蒙古1:50000德布斯格庙、达拉盖高勒、庙口幅”区域地质调查项目。选题为《内蒙古中部乌拉山岩群岩石地球化学特征和原岩建造》。研究区位于内蒙古中部乌拉山地区,大地构造位置属于华北克拉通北缘西部,燕山—阴山中生代板内造山带西段,具有复杂的大地构造背景。本文在充分了解和掌握前人资料和研究成果的基础上,通过对内蒙古中部乌拉山岩群系统的分析研究,查明了乌拉山岩群的空间分布规律、岩石组合特征、地层层序和岩石学特征,并以岩石地球化学数据为依据,利用各种原岩恢复图解,恢复了乌拉山岩群的原岩建造,取得了以下认识和成果:1、采用“构造—岩石—事件”方法,通过野外地质勘探以及典型实测剖面,根据特征标志层,结合岩石组合、分布、颜色、接触关系及矿物组成等特征,将乌拉山岩群划分为五个岩组,从下至上依次为角闪片麻岩岩组、黑云片麻岩岩组、榴云片麻岩岩组、石榴浅粒岩岩组和大理岩岩组。2、角闪片麻岩岩组以斜长角闪岩为标志层,主要岩石类型为:黑云角闪斜长片麻岩和角闪斜长片麻岩;黑云片麻岩岩组以石英岩为标志层,主要岩石类型为:黑云斜长片麻岩和黑云角闪斜长片麻岩;榴云片麻岩岩组是以富石榴石、矽线石、堇青石为特征的富铝片麻岩,主要岩石类型为:石榴黑云斜长片麻岩、石榴黑云二长片麻岩、黑云斜长片麻岩;石榴浅粒岩岩组以颜色和矿物含量上存在明显差异有别于榴云片麻岩岩组,主要岩石类型为:浅灰色黑云石榴二长浅粒岩、石榴斜长浅粒岩、矽线石榴变粒岩;大理岩岩组以蛇纹石化大理岩为特征。3、通过对地层特征、岩石类型、变质原岩恢复图解等方面综合分析,认为角闪片麻岩岩组原岩建造为火山岩夹一定量的碎屑沉积组成的火山—沉积建造;黑云片麻岩岩组为火山—沉积建造;榴云片麻岩岩组是以复矿物砂岩、杂砂岩、泥岩、陆相粘土岩为主的细碎屑沉积建造;石榴浅粒岩岩组原岩为杂砂岩的粗碎屑沉积建造;大理岩岩组为化学沉积建造。总体呈现出火山碎屑沉积—化学沉积的沉积旋回。
[Abstract]:The reconstruction of the early paleocontinent and the nature and evolution of the early continental crust have become one of the most important courses in modern geoscience.The study of the characteristics and genesis of the high grade metamorphic area in the early crustal development of the Wulashan rock group is of great scientific significance to the study of the formation and evolution of the early crust in this area.The paper relies on the regional geological survey project, I. e., Inner Mongolia 11: 50000 Debusig Temple, Dala Gegol, Miaokouzhuang.The selected topic is "petrogeochemical characteristics and original rock formation of the Wulashan rock group in central Inner Mongolia".The study area is located in the Wulashan area of central Inner Mongolia. The tectonic location is located in the western part of the northern margin of North China Craton and the western part of the Mesozoic intraplate orogenic belt of Yanshan-Yinshan, which has a complex tectonic background.On the basis of fully understanding and mastering the previous data and research results, the spatial distribution law and rock assemblage characteristics of the Wulashan rock group in the central part of Inner Mongolia have been found out through the analysis and study of the rock group system in this paper.Based on the stratigraphic sequence and petrological characteristics, and based on the petrogeochemical data, the original rock formation of the Wulashan rock group was restored by using various original rock restoration diagrams. The following knowledge and results were obtained: 1. The tectonic-rock-event method was adopted.By means of field geological exploration and typical measured profiles, according to the characteristic marker layer, combined with the characteristics of rock assemblage, distribution, color, contact relationship and mineral composition, the Wulashan rock group is divided into five rock formations.From the bottom to the top are hornblende gneiss formation, black cloud gneiss formation, eclogite gneiss formation, pomegranite formation and marble formation. The amphibolite is the marker layer of hornblende gneiss formation.The main rock types are: hornblende long gneiss and hornblende gneiss, the black cloud gneiss formation is marked by quartzite, and the main rock types are: black cloud amphibolite gneiss and black cloud hornblende plagioclase gneiss;The eclogite gneiss is aluminum-rich gneiss characterized by rich garnet, sillimanite and cordierite. The main rock types are: pomegranate black cloud plagiocline gneiss, pomegranate black cloud bigneiss, black cloud plagioclase gneiss;There are obvious differences in color and mineral content between the pomegranite formation and the eclogite gneiss formation. The main rock types are: light gray black cloud pomegranate, pomegranate plagioclase, siliceous pomegranate granulite;The marble formation is characterized by serpentinized marble. Through the comprehensive analysis of stratigraphic characteristics, rock types, metamorphic original rock restoration diagrams, etc.,It is considered that the original formation of hornblende gneiss is volcanic sedimentary formation composed of volcanic rocks with a certain amount of clastic deposits, the black cloud gneiss formation is volcanic-sedimentary formation, and the eclogite gneiss formation is composed of composite mineral sandstone, complex sandstone and mudstone.The continental claystone is dominated by fine clastic sedimentary formation; the pomegranate shallow-grained rock formation is composed of coarse clastic sedimentary formation of complex sandstone; and the marble formation is chemically sedimentary formation.There is a sedimentary cycle between pyroclastic and chemical deposits.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P587

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