渤黄海粘土粒级沉积物地球化学记录对物源和沉积环境的释读

发布时间：2018-04-06 02:09

本文选题：渤海　切入点：黄海　出处：《中国海洋大学》2014年硕士论文

【摘要】：地球是人类赖以生存的环境，人类的生存和发展与地球息息相关，随着人类的发展全球变化问题日益突出，为了我们人类更好的生存，环境问题成为我们现代社会研究的重要课题。海洋是地球的的重要组成部分，对地球的环境气候起着决定性作用，是全球变化研究的核心内容之一。海底的沉积物，它们记录着非常完好的地质发展历史，同时对海洋的化学与物理作用过程、全球的气候变化、环境历史的变化等多方面的信息也具有记录作用，对全面认识全球环境、气候变化规律具有重要意义。我国典型的两条大河长江、黄河，每年为我国东部陆架海输入大量的泥沙，为了了解我国东部陆架海的物源演化、时空分布及其环境的指示意义，因此很多学者把如何鉴别黄河、长江的物源作为研究的热点，而粘土矿物组分作为海洋沉积物的敏感粒级，在示踪沉积物源区物源输入和沉积环境方面具有非常好的灵敏度和可信度。本文分别通过对渤黄海区域表层样的粘土粒级沉积物进行地球化学分析和黄海北部B03岩芯的粒度、粘土矿物、沉积速率、粘土粒级沉积物地球化学分析，初步得到以下几点结论： (1) B03岩芯沉积物的粒度特征表明岩性表明岩芯上下比较均一，沉积记录连续，颗粒粒径均为0.25mm的细沙、粉砂及黏土，，主要为灰色、灰褐色粘土质粉砂，主要以粘土质粉砂为主，少部分为砂质粉砂；峰态系数、偏态系数、和分选系数整体变化范围不大，分选系数较差；沉积物自上而下粒径较细，粒度变化较小且沉积连续，说明了岩芯处于低能且稳定的沉积环境，水动力条件比较弱。 (2) B03岩芯粘土矿物组合特征呈现，岩芯主要以伊利石为主，也含有大量蒙脱石（11.0%-15.2%），三角端元图说明该岩芯源区主要来自黄河沉积物。在粘土矿物与粘土粒级沉积物的主微量的耦合关系中得出， B03岩芯粘土粒级沉积物中以富钙蒙皂石、富钾伊利石为特点，而在岩芯的主量元素垂向变化中我们得出CaO和K2O含量在以90cm为界分为上下两层，顶部的含量明显高于底部，说明其物源和环境都发生了一次显著地变化。 (3)在B03岩芯粘土粒级沉积物地球化学特征变化中，出现CaO、NaO、K2O、ΣREE等垂向图以90cm为界岩芯上下两段的变化，说明研究区在此处前后碎屑沉积物物源有了重大的改变。依据B03岩芯的210Pb测年数据分析，以B03岩芯的水深和长度计算，B03岩芯出现的90cm处上下分界线的沉积年龄为163a，而黄河尾间河段长期以来不断发生变迁改道，交替注入黄海、渤海，黄河曾于1855年由黄海入海改道至渤海，时间上推断该分界线和1855年黄河改道的时间相符，因此推测B03岩芯90cm上下两段沉积物的差异极可能是由黄河改道引起的。在黄河改道后山东半岛沿岸流携带的大量黄河物质在此处快速沉积，所以90cm以上的沉积物与黄河有很大的亲缘性，而在黄河未改道前，B03岩芯距离黄河河口较远，90cm以下的沉积物主要以接受山东半岛近岸及海底基岩剥蚀的产物为主。(4)通过对渤黄海粘土粒级沉积物元素地球化学特征研究，主微量成分特征和同一沉积年龄特征元素显示B23岩芯位于北黄海可能接受了朝鲜半岛和辽东半岛物源的影响其黄河高Ca的特征不明显；而B43岩芯位于渤海内，由于渤海为近封闭的一个环陆内海，主要的输入物源是陆源物质，所以其主量元素性质和变化与黄河物质一致，V、Ni、Co等风化作用的指示元素高于黄河，说明他们在沉积搬运中经历了一定的风化侵蚀，Zn、Cu等重金属元素的值也明显大于黄河，说明他们或多或少有一定的污染，B03的Cu、Zn含量最高，它从黄河口到山东半岛的运移过程中被污染的可能性比较大；稀土元素特征显示HL-2、HL-3和HK1和与黄河物质比较相似，其它样品的稀土元素含量均高于黄河物质稀土元素的含量，它们稀土元素具有的高含量值说明它们在沉积搬运过程中可能接受了其它物质来源的影响。
[Abstract]:The earth is the environment for human survival. The survival and development of mankind is closely related to the earth. With the development of mankind, the problem of global change is increasingly prominent. In order to better our human survival, environmental problems become an important research topic in our modern society.
The ocean is an important part of the earth, the earth's climate environment plays a decisive role, is one of the core contents of global change research. The seabed sediment, they are the records of the geological history is very good, and the physical and chemical effects on marine processes, global climate change, environmental change and other historical information the record also has effect on the comprehensive understanding of the global environment, plays an important role in the regulation of climate change.
China's two rivers typical of the Yangtze River, the Yellow River, every year in East China Sea continental shelf input a large amount of sediment, in order to understand the continental shelf of East China provenance evolution, spatial distribution and environmental significance, so many scholars regard how to identify the source of the Yellow River, the Yangtze River as a research hotspot, and clay mineral group as the sensitive grain size of marine sediments, has very good sensitivity and reliability of the tracer in the sediment source area of material sources and sedimentary environment.
Based on geochemical analysis of clay particle size sediments in the Bohai the Yellow Sea area, and the geochemical characteristics of the B03 core in northern the Yellow Sea, such as grain size, clay mineral, deposition rate and clay particle size, we have got the following conclusions.
(1) the grain size characteristics of core B03 sediments show that uniform lithology cores, sedimentary record, particle size was 0.25mm in the sand, silt and clay, mainly for gray, gray and brown clayey silt, mainly clayey silt, some sand silty sand; kurtosis coefficient of skewness coefficient, and sorting coefficient of the overall change range is not big, poor sorting coefficient; sediment from top to bottom with fine particles, particle size is smaller and the continuous deposition, the sedimentary environment in the core low and stable, the hydrodynamic condition is relatively weak.
(2) showed B03 core characteristics of clay minerals, rock mainly illite, also contains a large number of montmorillonite (11.0%-15.2%), triangular end member diagram shows that the rock core area is mainly from the the Yellow River sediments. In clay minerals and clay sediments of the main trace the coupling relationship that B03 core clay deposition
In the calcium rich smectite, illite potassium rich features, in the main elements of core vertical change we can CaO and K2O content in 90cm is divided into two layers, the top was significantly higher than that of the bottom, indicating its provenance and environment has undergone a significant change.
(3) in the B03 core clay sediments geochemical characteristics in the changes of CaO, NaO, K2O, REE and sigma vertical picture with 90cm changes on two core circles, that the study area has been significantly changed here before and after clastic sediment source. Based on the data analysis based on B03 core 210Pb, the core B03 depth and length calculation, 90cm core B03 appears on the deposition age boundary is 163a, while the the Yellow River reach between long tail change diversion, alternately into the Yellow Sea, the Yellow River in Bohai, the Yellow Sea in 1855 by the diversion to Bohai, the time that the demarcation line and 1855 the Yellow River diversion time consistent, suggesting that B03 core 90cm two differences in sediment is very likely caused by the diversion of the Yellow River in the Yellow River. After the diversion of Shandong Peninsula coastal current carrying a large number of substances in the Yellow River rapid deposition here, so to 90cm The sediment has great affinity with the Yellow River, and in the Yellow River without diversion before, B03 core is relatively far from the mouth of the the Yellow River River, sediments below 90cm mainly in the Shandong Peninsula and accept the product of the seabed erosion mainly. (4) through the study on the geochemical characteristics of elements in sediments of Bohai the Yellow Sea clay, the main trace components the same features and sedimentary age characteristics of display elements of core B23 in northern the Yellow Sea may be influenced by the Korean Peninsula and the Liaodong Peninsula source high Ca the Yellow River feature is not obvious; while the core B43 is located in Bohai, Bohai due to a ring of land sea nearly closed, the main source is the input of terrigenous materials. So the main elements and material properties and changes of the Yellow River, V, Ni, Co and other indicator elements in weathering is higher than that in the Yellow River, they experienced weathering and erosion, Zn in the deposition of the transportation, Cu and other heavy metals The value is obviously higher than that of the Yellow River, they have more or less pollution, B03 Cu, Zn was the highest, the likelihood of contamination from the Yellow River mouth to the Shandong Peninsula in the process of migration is relatively large; REE characteristics show that HL-2, HL-3 and HK1 and the the Yellow River matter is quite similar, the content of rare earth elements in other samples were the Yellow River is higher than the material of rare earth elements, rare earth elements have a high content of their value in that they deposited in the process of handling may accept the influence from other substances.

【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P736

【参考文献】