东海典型泥质区高分辨沉积记录及其对气候环境变化的响应

发布时间：2018-05-07 04:09

  本文选题：内陆架泥质区 + 远端泥质区　； 参考：《中国海洋大学》2014年博士论文

【摘要】：陆架泥质沉积体形成于冰后期高水位时期，接受来自大江、大河以及人类活动进入海洋的陆源物质、污染物质，具有高的沉积速率，是开展全球变化区域性响应以及边缘海陆海相互作用研究的良好选区。东海陆架受到其西侧的陆源输入和来自其东侧的西太平洋强劲的边界流共同制约，陆架上发育的泥质沉积区无疑是记录来自东、西两侧影响的理想位置，而不同位置的泥质沉积体因离长江口远近、海洋动力因素、水深等的差异，导致它们在记录气候环境变化上异同。因此，本研究把内陆架泥质区、远端泥质区看作一个整体，开展多参数的年际－年代际高分辨沉积记录研究，揭示该区沉积作用对全球变化的区域响应特征，为全球变化的区域响应提供科学支持。 本文通过对采自东海内陆架泥质区的C0702、C0803站和济州岛西南的远端泥质区CFJ103站等3个沉积物岩芯，以及100多个表层沉积物样品，开展了沉积物粒度、黏土矿物、常微量元素以及生物硅分析测试，结合放射性核素测年建立了内陆架及远端泥质区数百年来的高分辨沉积记录，通过与影响该区的全球气候环境因素的比较研究，配合功率谱（REDFIT）及经典模态分解（EMD）等周期分析数学方法的应用，阐明高分辨沉积记录对全球变化和人类活动的响应特征和影响机制。研究取得如下主要成果： （1）内陆架泥质区、远端泥质区在沉积速率和沉积物组成上具有明显的差异。内陆架泥质区沉积速率高、沉积速率不稳定，其沉积物主要来自长江；远端的济州岛泥质区沉积速率低、稳定，其沉积物来源受到废黄河侵蚀物质的明显影响。 （2）建立了内陆架泥质区、远端泥质区高分辨的粒度、黏土矿物、元素、生物硅及生源钡的沉积记录，揭示了该区沉积记录阶段性、趋势性和周期性等变化特点。风暴潮、洪水等事件过程引起沉积物粒度和元素含量、黏土矿物含量的突变，而近50年来人类活动主要体现在沉积记录中Pb、Zn等重金属含量明显富集。 （3）内陆架泥质区黏土矿物组成在1950年前后的存在明显变化，表现为伊利石含量的降低、高岭石和绿泥石含量的升高，主要源于东亚冬季风控制下的沿岸流及上升流的强度的年际差异以及陆源物质入海通量的改变。 （4）内陆架泥质区、远端泥质区的粒度组成和东亚冬季风有着良好的响应关系，当冬季风增强时沉积物的粗粒组分含量增大，代表冬季风的敏感粒级组分的含量和平均粒径均有随之升高。内陆架主要受东亚季风控制下东海沿岸流强度变化的影响，而济州岛西南则主要受到东海冷涡及上升流的影响。 （5）东海陆架沉积物中生物硅含量受粒度的显著影响，，它在16μm沉积物组分中含量最高，这与该海域硅藻群落构成及水动力环境有关。 （6）估算了东部陆架细粒沉积物的生物硅沉积通量，高值区位于长江口和内陆架泥质区，其次是黄海南部泥质区。生物硅沉积通量的空间分布形式与浮游植物生产力水平对应良好，并与沉积速率密切相关。 （7）东海内陆架泥质区生物硅的记录了该区近数百年来的硅藻生产力波动，发现了该波动和季风强弱、太阳黑子活动、ENSO及PDO等存在良好响应，同时揭示了近30年来生物硅含量减小趋势与人类活动影响下营养物质输入的差异引起的生态系统硅藻比例下降有关。
[Abstract]:The continental shelf of continental shelf is formed in the period of high water level at the later stage of ice . It is a good selection area for the study of land - source substances and pollutants from large rivers , rivers and human activities into the ocean . It is a good selection area for the regional response of global change and strong boundary flow in the marginal sea . The continental shelf of the East China Sea is regarded as a whole by the land source input on the west side and the strong boundary flow from the west Pacific on the east side . Therefore , this study regards the inland frame mud area and the far - end muddy area as a whole , and carries out multi - parameter interannual high - resolution sedimentary record research , and reveals the regional response characteristics of the sedimentary effect of the region to the global change , and provides scientific support for the regional response of the global change .

In this paper , three sediment cores , such as C0702 , C0803 , and CFJ103 , located in the mud area of the inland frame of East China Sea , were collected , and the sediment size , clay minerals , trace elements and biological silicon analytical tests were carried out .

( 1 ) There is a significant difference between the sediment rate and the sediment composition in the mud area of the inland frame . The deposit rate of the inland frame is high , the sedimentation rate is unstable , and its sediments mainly come from the Yangtze River ;
The sedimentary rate of the puzhou island is low and stable at the distal end . The sediment source is affected by the erosion of the waste Yellow River .

( 2 ) The sedimentary records of high resolution grain size , clay minerals , elements , biological silicon and source barium in the mud area of the inland frame were established , and the characteristics of phase , tendency and periodicity of the sedimentary records were revealed . The events of storm tide and flood caused the change of the grain size and the content of elements and clay minerals , while in the past 50 years , human activities mainly reflected the significant enrichment of heavy metals such as Pb , Zn and the like in the sedimentary records .

( 3 ) The composition of clay minerals in the mud area of the inland frame was obviously changed before and after 1950 , showing the decrease of the content of Illite , the increase of the content of kaolinite and chlorite , mainly due to the annual difference of the coastal flow and the intensity of the upwelling of the East Asian winter wind and the change of the sea flux of the terrigenous material .

( 4 ) The grain size composition and the East Asian winter monsoon have a good relationship between the grain size composition and the East Asian winter monsoon . When winter wind is strengthened , the content of coarse particles of sediments increases , and the content and average particle size of the sensitive grain fraction representing the winter monsoon are increased . The inland shelf is mainly affected by the change of the coastal flow intensity of the East China Sea under the control of East Asian monsoon , while the southwest of Jeju Island is mainly affected by the cold vortex and upwelling of the East China Sea .

( 5 ) The content of biological silicon in the sediments of the East China Sea shelf is affected by the particle size , which is the highest in the 16 渭m sediment component , which is related to the composition of diatoms in the sea area and the hydrodynamic environment .

( 6 ) The biological silicon deposition flux of the fine sediments in the eastern continental shelf is estimated , and the high value area is located in the mud area of the Yangtze River Estuary and the Inland Shelf , followed by the mud area in the southern Yellow Sea . The spatial distribution of the biological silicon deposition flux corresponds well to the phytoplankton productivity level and is closely related to the deposition rate .

( 7 ) The biological silicon in the inner shelf of the East China Sea recorded the fluctuation of the productivity of diatoms in the region in recent hundreds of years . It has been found that there is a good response to the fluctuation and the strong weak of the monsoon , the activities of the solar black and the like and the PDO and so on , and also reveals that the decrease of the biological silicon content in the last 30 years is related to the decrease of the proportion of the algae in the ecosystem caused by the difference of nutrient inputs under the influence of human activities .

【学位授予单位】：中国海洋大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：P736.21

【参考文献】

中国期刊全文数据库 前10条

1 陈家其,施雅风;长江三角洲千年冬温序列与古里雅冰芯比较[J];冰川冻土;2002年01期

2 张月丛,孟宪锋;厄尔尼诺和拉尼娜的成因及其对中国气候的影响[J];承德民族师专学报;2005年02期

3 钟颖e

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