發(fā)布時間：2018-05-07 04:09

  本文選題：內陸架泥質區(qū) + 遠端泥質區(qū)�。� 參考：《中國海洋大學》2014年博士論文

【摘要】：陸架泥質沉積體形成于冰后期高水位時期，接受來自大江、大河以及人類活動進入海洋的陸源物質、污染物質，具有高的沉積速率，是開展全球變化區(qū)域性響應以及邊緣海陸海相互作用研究的良好選區(qū)。東海陸架受到其西側的陸源輸入和來自其東側的西太平洋強勁的邊界流共同制約，陸架上發(fā)育的泥質沉積區(qū)無疑是記錄來自東、西兩側影響的理想位置，而不同位置的泥質沉積體因離長江口遠近、海洋動力因素、水深等的差異，導致它們在記錄氣候環(huán)境變化上異同。因此，本研究把內陸架泥質區(qū)、遠端泥質區(qū)看作一個整體，開展多參數的年際－年代際高分辨沉積記錄研究，揭示該區(qū)沉積作用對全球變化的區(qū)域響應特征，為全球變化的區(qū)域響應提供科學支持。 本文通過對采自東海內陸架泥質區(qū)的C0702、C0803站和濟州島西南的遠端泥質區(qū)CFJ103站等3個沉積物巖芯，以及100多個表層沉積物樣品，開展了沉積物粒度、黏土礦物、常微量元素以及生物硅分析測試，結合放射性核素測年建立了內陸架及遠端泥質區(qū)數百年來的高分辨沉積記錄，通過與影響該區(qū)的全球氣候環(huán)境因素的比較研究，配合功率譜（REDFIT）及經典模態(tài)分解（EMD）等周期分析數學方法的應用，闡明高分辨沉積記錄對全球變化和人類活動的響應特征和影響機制。研究取得如下主要成果： （1）內陸架泥質區(qū)、遠端泥質區(qū)在沉積速率和沉積物組成上具有明顯的差異。內陸架泥質區(qū)沉積速率高、沉積速率不穩(wěn)定，其沉積物主要來自長江；遠端的濟州島泥質區(qū)沉積速率低、穩(wěn)定，其沉積物來源受到廢黃河侵蝕物質的明顯影響。 （2）建立了內陸架泥質區(qū)、遠端泥質區(qū)高分辨的粒度、黏土礦物、元素、生物硅及生源鋇的沉積記錄，揭示了該區(qū)沉積記錄階段性、趨勢性和周期性等變化特點。風暴潮、洪水等事件過程引起沉積物粒度和元素含量、黏土礦物含量的突變，而近50年來人類活動主要體現在沉積記錄中Pb、Zn等重金屬含量明顯富集。 （3）內陸架泥質區(qū)黏土礦物組成在1950年前后的存在明顯變化，表現為伊利石含量的降低、高嶺石和綠泥石含量的升高，主要源于東亞冬季風控制下的沿岸流及上升流的強度的年際差異以及陸源物質入海通量的改變。 （4）內陸架泥質區(qū)、遠端泥質區(qū)的粒度組成和東亞冬季風有著良好的響應關系，當冬季風增強時沉積物的粗粒組分含量增大，代表冬季風的敏感粒級組分的含量和平均粒徑均有隨之升高。內陸架主要受東亞季風控制下東海沿岸流強度變化的影響，而濟州島西南則主要受到東海冷渦及上升流的影響。 （5）東海陸架沉積物中生物硅含量受粒度的顯著影響，，它在16μm沉積物組分中含量最高，這與該海域硅藻群落構成及水動力環(huán)境有關。 （6）估算了東部陸架細粒沉積物的生物硅沉積通量，高值區(qū)位于長江口和內陸架泥質區(qū)，其次是黃海南部泥質區(qū)。生物硅沉積通量的空間分布形式與浮游植物生產力水平對應良好，并與沉積速率密切相關。 （7）東海內陸架泥質區(qū)生物硅的記錄了該區(qū)近數百年來的硅藻生產力波動，發(fā)現了該波動和季風強弱、太陽黑子活動、ENSO及PDO等存在良好響應，同時揭示了近30年來生物硅含量減小趨勢與人類活動影響下營養(yǎng)物質輸入的差異引起的生態(tài)系統(tǒng)硅藻比例下降有關。
[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 .

【學位授予單位】：中國海洋大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：P736.21

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3 鐘穎e

本文編號：1855333