延边西部水系沉积物地球化学异常筛选及评价

发布时间：2018-02-26 19:35

本文关键词： 异常识别多元统计分类法异常评价森林景观区延边西部　出处：《吉林大学》2015年硕士论文　论文类型：学位论文

【摘要】：延边西部属于典型森林景观区，，植被覆盖严重，自然露头较少，找矿难度大。大量找矿实践表明，化探方法是该类景观区找矿的主要手段。在此类景观区进行化探采样时，往往采用较粗粒级的样品以避免有机质的影响，但同时岩性背景的强烈影响使得元素背景值确定更加困难，直接影响了地球化学异常识别，特别是低弱异常的识别。研究区位于龙岗地块陆缘活动带与佳木斯地块陆缘活动带交界处，北东向的敦密断裂贯穿全区，出露元古界、古生界、中生界以及新生界地层。研究区经历多期次岩浆侵入，以燕山期的岩浆活动最为强烈、侵入岩类型最为复杂，这为区内形成更多有工业价值的矿床提供了有利的成矿环境。本文分析了该区水系沉积物元素含量的空间分布特点及其与地质背景的关系，研究了水系沉积物主要元素（氧化物）含量的概率分布形式以及成矿元素与岩石化学成分的关系。在此基础上，采用地质分类法和以K值动态聚类为核心的多元统计分类法对研究区水系沉积物元素异常进行圈定。与常规异常圈定方法对比研究表明，地质分类法可以在一定程度上消除岩性背景的影响，但也存在着精度不高的缺陷，而多元统计分类法可以有效消除岩性背景的影响，较好地提取低弱异常。在上述研究的基础上，根据地球化学异常评价准则，对研究区主要地球化学异常进行评价。根据地球化学综合异常、已知矿点分布及其地质背景，圈定了成矿远景区。
[Abstract]:The west of Yanbian is a typical forest landscape area with serious vegetation coverage, less natural outcrop and difficulty in prospecting. A large number of prospecting practices show that geochemical prospecting is the main method for prospecting in this kind of landscape area. Coarse-grained samples are often used to avoid the influence of organic matter, but at the same time, the strong influence of lithologic background makes it more difficult to determine the background value of elements, which directly affects the identification of geochemical anomalies, especially the identification of low and weak anomalies. The study area is located at the junction of the active belt of the continental margin of the Longgang block and the active belt of the Jiamusi block. The NNE Dumi fault runs through the whole area, showing the Proterozoic, Paleozoic, Mesozoic and Cenozoic strata. The study area has experienced multiple magmatic intrusions. The Yanshanian magmatic activity is the strongest and the intrusive rock type is the most complex, which provides a favorable metallogenic environment for the formation of more industrial deposits in the area. In this paper, the spatial distribution characteristics of element contents in river sediments and their relationship with geological background are analyzed. The probability distribution of main elements (oxides) in river sediments and the relationship between ore-forming elements and rock chemical composition are studied. The geological classification method and the multivariate statistical classification method with K value dynamic clustering as the core are used to delineate the element anomalies of river sediment in the study area. The geological classification method can eliminate the influence of lithologic background to some extent, but it also has the defect of low precision. The multivariate statistical classification method can effectively eliminate the influence of lithologic background and extract low and weak anomalies. On the basis of the above research, the main geochemical anomalies in the study area are evaluated according to the evaluation criteria of geochemical anomalies. According to the geochemical comprehensive anomalies, the known distribution of ore points and their geological background, the metallogenic distant areas are delineated.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P632

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