兴蒙—华北地球化学走廊带元素时空分布与对比

发布时间：2018-03-12 15:16

本文选题：兴蒙造山带-华北克拉通　切入点：地球化学走廊带　出处：《中国地质大学(北京)》2017年博士论文　论文类型：学位论文

【摘要】：为研究兴蒙造山带-华北克拉通地球化学走廊带区域地球化学组成及其横向空间变化,以1～4km高密度分别采集沉积物和岩石样品550件和1309件,选取主量元素、成矿元素和稀土元素进行数理统计,并以地球化学剖面图的形式展示其空间分布;对岩石样品进行分类,并统计不同岩性和地质时代元素含量特征,重点讨论了岩浆岩SiO_2、Au及花岗岩中稀土元素时代特征。结果表明:(1)SiO_2与Al_2O_3对比,表明沉积物中矿物组成是影响其含量的重要因素之一,CaO、MgO的富集主要与碳酸盐岩密切相关,降雨量对Na_2O、K_2O在沉积物中的富集影响显著且存在差异。主量元素在沉积物中含量与空间分布除了受继承的基岩影响外,还受到后期的风化作用和气候及自身地球化学性质等复杂因素综合影响。SiO_2的含量时代变化反映了上地壳酸性演化的趋势,其在海西期岩浆岩中的含量最高。H20+的含量普遍较低,仅碳酸盐岩或第四系局部较高,pH值反映北方沉积物偏碱性。(2)Au的富集与太古代-元古代结晶基底密切相关,燕山造山带Au的富集系数明显大于鲁西地块,这也与其Au矿发现与分布相符。Ag与Cu富集系数曲线十分相似,而Pb、Zn则几乎完全一致,与它们矿物密切共生有关。W富集系数曲线完美诠释了其在花岗岩中富集的特点,在平原沉积物中较高含量,这可能受到来自燕山造山带和鲁西地块的明显影响。Ti与基性-超基性岩分布的空间对应较好;江苏北部沉积物V的异常富集,应与鲁西地块有关。(3)沉积物和岩石ΣREE含量的空间分布,表明源区决定了稀土元素在不同构造单元之间的整体差异,但表生条件在局部的差异也发挥着重要影响。REE含量在不同花岗岩类、构造单元之间的差异相对地质时代而言要大,且同一类花岗岩在不同地质时代也如此,表明其在不同地质时代形成过程所经历的不同岩浆地质作用。(4)地理信息系统(GIS)强大的属性数据和空间属性关联查询的特点,可以更好地管理地球化学样品数据,提供进一步挖掘地球化学数据的潜在信息和应用于基础地质、矿产预测和农业生产等活动的基础。总之,地球表层复杂系统中,表生环境对沉积物含量与空间分布影响复杂而重要,如:地理景观、气候因素,等。生物作用和人类工、农业活动对土壤含量变化的影响值得关注,其复杂机理和空间分布值得更系统深入的研究,GIS可以发挥很好的作用。
[Abstract]:In order to study the regional geochemical composition and lateral spatial variation of Xingmeng orogenic belt and North China Craton geochemical corridor zone, 550 and 1309 samples of sediments and rocks were collected with high density of 1 ~ 4km, and principal elements were selected. Metallogenic elements and rare earth elements are mathematically counted, and their spatial distribution is shown in the form of geochemical profiles. Rock samples are classified and the characteristics of element contents in different lithology and geological times are counted. The age characteristics of rare earth elements in magmatic rock SiOSZ 2au and granite are discussed in detail. The results show that the mineral composition in sediments is one of the important factors affecting its content, and the enrichment of MgO in sediments is closely related to carbonate rocks, the results show that the composition of minerals in sediments is one of the most important factors affecting the content of SiO-1, and the enrichment of MgO in granites is closely related to carbonate rocks. Rainfall has a significant effect on the enrichment of Na _ 2O _ 2 K _ 2O in sediments, and there are significant differences in the concentration and spatial distribution of principal elements in sediments, except for the inherited bedrock. The complex factors such as weathering, climate and geochemical properties of the late period also influenced the time variation of the content of .SiO-2, which reflected the trend of acid evolution in the upper crust. The content of .H20 in the Hercynian magmatic rocks was generally the highest, and the content of .H20 was generally lower in the magmatic rocks of the Hercynian period. Only the higher pH values of carbonate rocks or Quaternary regions reflect that the enrichment of au in the sediments of northern China is closely related to the Archean to Proterozoic crystalline basement, and the enrichment coefficient of au in the Yanshanian orogenic belt is obviously larger than that in the western Shandong block. This is similar to the au ore discovery and distribution. Ag and Cu enrichment coefficient curves are very similar, while PBN Zn is almost identical. The .W enrichment coefficient curve, which is closely related to their mineral symbiosis, perfectly interprets its characteristics of enrichment in granite. The higher content in plain sediments may be affected by the obvious influence of Yanshanian orogenic belt and western Shandong massif on the spatial distribution of basic-ultrabasic rocks, and the anomalous enrichment of V in sediments of northern Jiangsu Province. The spatial distribution of 危 REE content in sediments and rocks is related to the Luxi massif, indicating that the source region determines the overall difference of rare earth elements among different tectonic units. However, the local differences of supergene conditions also play an important role in the different granitic types. The difference between tectonic units is larger than that of geological age, and the same type of granite is the same in different geological ages. It is shown that the strong attribute data and spatial attribute association query characteristics of different magmatic geological processes experienced in different geological ages can better manage geochemical sample data, and the GIS (Geographic Information system) (GIS) has the characteristics of strong attribute data and spatial attribute association query, which can better manage geochemical sample data. Providing potential information for further mining geochemical data and the basis for application to activities such as basic geology, mineral prediction and agricultural production. In summary, in complex systems of the Earth's surface, The influence of supergene environment on sediment content and spatial distribution is complex and important, such as geographical landscape, climatic factors, etc. The complex mechanism and spatial distribution of GIS can play a good role.
【学位授予单位】：中国地质大学(北京)
【学位级别】：博士
【学位授予年份】：2017
【分类号】：P632;P622.3

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