内蒙古拐子湖地区三叠纪地层研究

发布时间：2018-02-14 12:45

本文关键词： 三叠系珊瑚井组沉积相沉积亚相含矿性分析　出处：《长安大学》2017年硕士论文　论文类型：学位论文

【摘要】：研究区属于内蒙古自治区额济纳旗,地处荒漠戈壁,人烟稀少,交通闭塞。三叠系珊瑚井组是本次1:5万区域矿产地质调查项目实施过程中发现并划分出的地层单元,前人1:20万区调中将该地层归入石炭系绿条山组。本文在前人研究的基础上,以沉积岩石学、古生物学、矿床学等基础理论为指导,立足野外实测剖面、路线调查资料,结合微量元素分析资料、粒度分析资料、薄片鉴定资料、土壤地球化学资料等,对三叠纪地层的沉积建造、沉积环境、形成时代及找矿潜力进行分析和研究,获得如下成果和认识:(1)研究区该套地层属于陆相红色含砾粗碎屑岩建造并含有植物化石,依据区域对比将该套陆相碎屑岩归为三叠系珊瑚井组,其时代为晚三叠世。(2)根据三叠系珊瑚井组岩石组合特征,将珊瑚井组进一步划分为上下两段,下段为粗碎屑岩组合,主要岩性为:紫红色-红褐色砾岩、含砾砂岩、细砂岩旋回;上段为细碎屑岩组合,主要岩性为:灰白色-灰色粗砂岩-细砂岩-粉砂岩-泥岩旋回。(3)通过对研究区三叠纪地层大量的野外实测和室内资料研究,结合岩石颜色、结构、构造、粒度分析、微量元素等沉积相标志,将研究区珊瑚井组地层划分为2个沉积相、5个沉积亚相和8个沉积微相,即辫状河相、曲流河相,其中辫状河相又分为河床亚相、泛滥平原亚相;曲流河相分为河床亚相、河漫亚相和堤岸亚相;各沉积亚相又可以划分出不同的沉积微相。(4)三叠系珊瑚井组地层中As、Sb、Pb、W元素丰度值较高,且相关性较好,元素高值主要分布于珊瑚井组砂砾岩中;该区的化探异常分布与珊瑚井组地层展布具有一致性,综合研究认为珊瑚井组砂砾岩受热液及断裂破碎带影响As、Sb、Pb、W元素丰度值较高,具有一定找矿潜力。
[Abstract]:The research area belongs to the Ejina Banner of Inner Mongolia Autonomous region, located in the desert Gobi, sparsely populated and closed in traffic. The Triassic Coral well formation is a stratigraphic unit discovered and divided during the implementation of the 1: 50 000 regional mineral geological survey project. The strata are classified into the Lutiaoshan formation of Carboniferous in the 1:20 regional survey. Based on the previous studies, and guided by the basic theories of sedimentary petrology, paleontology and ore deposit science, this paper bases itself on the field measured profiles and route investigation data. Combined with trace element analysis data, grain size analysis data, sheet identification data and soil geochemical data, the sedimentary formation, sedimentary environment, forming age and prospecting potential of Triassic strata are analyzed and studied. The formation belongs to the continental red gravel-bearing coarse clastic rock formation and contains plant fossils. According to the regional correlation, the continental clastic rock is classified into Triassic coral well formation. According to the characteristics of the rock assemblages of the Triassic Coral well formation, the coralline well formation is further divided into the upper and lower sections, and the lower member is the coarse clastic rock assemblage, the main lithology is: purple-red-red-brown conglomerate, gravel-bearing sandstone. The upper member is composed of fine clastic rock assemblage, the main lithology is: grayish-gray coarse sandstone, fine sandstone, siltstone and mudstone cycle. Combined with the color, structure, structure, granularity analysis and trace elements of sedimentary facies, the formation of coral well formation in the study area is divided into 2 sedimentary facies, 5 sedimentary subfacies and 8 sedimentary microfacies, namely braided fluvial facies, meandering river facies, etc. The braided river facies are divided into river bed subfacies, flood plain subfacies, meandering river facies into river bed subfacies, river diffuse subfacies and embankment subfacies. Each sedimentary subfacies can be divided into different sedimentary microfacies. 4) the abundance value of element As-SbSbPbCW in the formation of Triassic coral well group is higher and the correlation is good. The high value of element is mainly distributed in the sand and gravel rock of the coral well group. The geochemical anomaly distribution in this area is consistent with the distribution of the formation of the coral well group. It is considered that the thermal fluid of the sandy gravel rock and the fracture fracture zone of the coral well group affect the abundance value of the element As-SbPbCw, which has a certain prospecting potential.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P534.51

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