乌伦古地区石炭系火成岩岩性特征及其元素地球化学响应

发布时间：2018-03-24 11:31

本文选题：乌伦古　切入点：火山岩　出处：《中国矿业大学》2015年硕士论文

【摘要】：本文以准噶尔盆地北部乌伦古地区为研究区,以石炭系火山岩为主要研究对象,利用岩石学和元素地球化学的方法,结合测井曲线和地震剖面参数,系统探讨了火山岩的岩石元素地球化学特征、构造环境、旋回划分以及小波分析处理元素地球化学数据在旋回识别方面等地质问题。通过本文研究工作,主要取得如下认识:(1)通过岩石薄片鉴定以及野外剖面资料,分析出研究区火山岩类型主要有:安山岩、火山角砾岩、火山角砾凝灰岩、火山凝灰岩(正常火山碎屑岩类)与沉凝灰岩和凝灰质粉砂岩、凝灰质泥岩。(2)通过元素地球化学分析,研究区原始岩石具有同源性,Pb富集和Nb亏损反映原岩部分来自地壳。根据构造环境判别图,判定研究区火成岩形成的构造环境为火山岛弧型构造环境,并且在形成过程中,有地壳物质混入岩浆源。(3)乌伦古地区石炭系火山岩岩相划分为火山沉积相组、火山喷发相组等2相组,火山沉积相、溢流相、爆发相等3相,过渡亚相、喷发沉积亚相、上部亚相、下部亚相、热碎屑流亚相、空落亚相等6亚相。(4)通过小波分析处理主成分地球化学数据,划分火山旋回及韵律,并结合岩石鉴定、测井数据和地球化学数据,将研究区石炭系火山岩系的4个旋回和18个期次加以描述同时也验证了小波分析预测火成岩旋回和韵律的有效性。
[Abstract]:In this paper, taking the Ulungu area in the north of Junggar Basin as the study area, taking the Carboniferous volcanic rocks as the main research object, using the methods of petrology and elemental geochemistry, combining the log curves and seismic profile parameters, The geochemistry characteristics of volcanic rocks, tectonic environment, cycle division and the cycle identification of element geochemistry data by wavelet analysis are systematically discussed in this paper. The main results are as follows: (1) through the identification of thin sections of rocks and field profile data, it is found that the main types of volcanic rocks in the study area are: andesite, volcanic breccia, volcanic breccia, volcanic breccia, volcanic breccia, volcanic breccia, and volcanic breccia. Volcanic tuff (normal pyroclastic rock) and tuff and tuffaceous siltstone, tuffaceous mudstone, by element geochemical analysis, The primary rocks in the study area have the homology of Pb enrichment and NB depletion, which reflect that part of the primary rocks come from the crust. According to the tectonic environment discriminant diagram, the tectonic environment of igneous rocks in the study area is determined to be volcanic island arc tectonic environment, and during the process of formation, the tectonic environment of igneous rocks in the study area is determined. The lithofacies of Carboniferous volcanic rocks in the Wulungu area are divided into volcanic sedimentary facies, volcanic eruption facies, volcanic sedimentary facies, overflow facies, eruption equivalent 3 facies, transitional subfacies, eruption sedimentary subfacies, etc. The upper subfacies, the lower subfacies, the thermoclastic flow subfacies, the empty subfacies equal 6 subfacies. 4) the principal component geochemical data are processed by wavelet analysis, the volcanic cycles and rhythms are divided, and the rock identification, logging data and geochemical data are combined. The four cycles and 18 periods of Carboniferous volcanic rock series in the study area are described and the validity of wavelet analysis in predicting igneous rock cycles and rhythms is also verified.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P588.14;P595

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