渤海湾表层沉积物地球化学研究

发布时间：2018-06-12 07:41

本文选题：渤海湾 + 海底表层沉积物　；参考：《中国地质科学院》2014年硕士论文

【摘要】：本文依托中国地质调查局地质调查项目“近海区域地球化学调查技术研究”完成。根据对采集的100个表层沉积物样品所做的元素地球化学分析,在前人的研究基础上,分析了渤海湾表层沉积物的地球化学特征,解释了沉积物中常量元素和微量元素的变化规律,论述了元素的分布特征、稀土元素的物源指示意义以及元素之间的相关关系与组合特征,在此基础上,通过海洋沉积物的重金属污染评价方法,初步了解渤海湾底质环境质量状况。通过对渤海湾表层沉积物地球化学的全面研究,获得了以下几点认识和结论： (1)常量组分SiO2、A12O3、MgO、CaO、TFe2O3、Na2O、K20等含量从近岸向远岸表现出不同的变化趋势。SiO2、Al2O3含量呈现降低趋势,主要受陆源碎屑补给减弱影响,而MgO、CaO的含量则略微上升,是海洋生物补给的结果,TFe2O3、Na2O、K20的含量变化不明显。大多数微量元素随着离岸距离的增加并没有明显的变化规律。而Zr、Hf、Hg、Pb等元素受陆源补给的影响,含量出现降低的趋势,As、Br、 Cl、Cd、Co、Cr、Cs、Cu、Ga、Mn、Mo、Ni、Sb、Sn, Zn、V、W等元素的含量在油气藏的影响下出现上升的趋势。在元素性质和物质来源的影响下,表层沉积物中的元素呈现几种典型的分布情况：Al、Fe、K分布情况相似,高值区主要分布在北部和东部,Ca与Na相反,Na2O的高值区主要分布在研究区的中部和北部；Rb、Co、Ga、Cs、Ni、V分布相似,主要富集在东北区域；Hf、I、Zr、Sr分布相似,主要富集在西北区域,与Na相似；Mn、 Mo、Sb的分布相似,主要富集在西南区域。 (2)根据元素的因子分析和聚类分析的结果,结合元素异常分布特征,将元素分为4个组合,第一组：As、Sb、Mn、Mo、Pb、I、Cl、Br;第二组：Sr、CaO、TC;第三组：Zr、Hf;第四组：Co、Ni、Cs、Cu、Ga、Cr、V、Rb、Zn。每个组合都有特定的元素来源和分布意义。 (3)通过海洋沉积物质量标准(GB-18668-2002)、地累积指数、潜在生态危害指数三种方法对渤海湾表层沉积物中重金属进行评价,研究发现,目前渤海湾表层沉积物中重金属含量均属于安全范围内,沉积物比较清洁,生态危害较轻,但Pb、Cd、Hg由于其潜在生态危害指数较大,需要引起重视。
[Abstract]:This paper is based on the geological survey project of China Geological Survey. Based on the elemental geochemical analysis of 100 surface sediment samples collected, the geochemical characteristics of surface sediments in Bohai Bay are analyzed on the basis of previous studies. The variation law of constant elements and trace elements in sediment is explained, and the distribution characteristics of elements, the signifying significance of the source of rare earth elements, and the correlation and combination characteristics among elements are discussed. Through the method of heavy metal pollution assessment in marine sediments, the environmental quality of bottom sediments in Bohai Bay was preliminarily understood. Based on a comprehensive study of the geochemistry of surface sediments in Bohai Bay, the following conclusions have been obtained: (1) the contents of the constant component SiO2OA12O3, MgO, Cao, TFe2O3, Na2OK20, etc., show a different trend of change from the near shore to the far shore. The content of SiO2Al2O3 shows a decreasing trend, and the content of SiO2Al2O3 shows a decreasing trend from the near shore to the far shore. It is mainly affected by terrestrial clastic recharge, while the content of MgO- CaO increases slightly, which is the result of marine recharge. The content of TFE _ 2O _ 3N _ (Na _ 2O) K _ (20) does not change obviously. Most trace elements do not change with the increase of offshore distance. However, under the influence of terrestrial recharge, the contents of elements such as Zr, HfG, Pb and so on have a decreasing trend. The contents of elements such as As-Brr, Cl-CdCa-CoCr-Cr-CsPU, NiSbSnC, ZnV, W, and so on, are rising under the influence of oil and gas reservoirs, and under the influence of elemental properties and material sources, the contents of these elements have a tendency to increase. The distribution of elements in surface sediments is similar in several typical distributions. The high value areas are mainly distributed in the northern and eastern regions of the north and east of China. The high value areas of Ca and Na are mainly distributed in the central and northern parts of the study area. It is mainly enriched in the northeast of China, and is mainly enriched in the northwest region, similar to the distribution of Na, mn and Mo-Sb, and mainly concentrated in the southwest region. 2) according to the results of factor analysis and cluster analysis of elements, the anomalous distribution of elements is considered. The elements were divided into four combinations. The first group was composed of two groups: the first group was divided into four groups: the first group was composed of two groups, the second group was the first group, the other group was the second group. The second group was the second group; the third group was the second group. Each combination has a specific element source and distribution significance. (3) through three methods of marine sediment quality standard (GB-18668-2002), ground accumulation index and potential ecological hazard index, the heavy metals in the surface sediments of Bohai Bay were evaluated. The contents of heavy metals in the surface sediments of Bohai Bay are all within the safe range at present. The sediments are relatively clean and the ecological harm is relatively light. However, due to its large potential ecological hazard index, PBN CDH Hg needs to be paid more attention to.
【学位授予单位】：中国地质科学院
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P736.4

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