近百年來(lái)長(zhǎng)江口濱外區(qū)沉積作用及其對(duì)環(huán)境變化的響應(yīng)
發(fā)布時(shí)間：2018-11-03 16:05
【摘要】：長(zhǎng)江流域帶來(lái)豐富的陸源碎屑沉積物，在河口及淺海陸架區(qū)形成了龐大的河口三角洲，三角洲的沉積演化過(guò)程研究對(duì)揭示陸海相互作用具有重要意義。長(zhǎng)江口外泥質(zhì)區(qū)沉積速率較高，具有相對(duì)穩(wěn)定、連續(xù)的沉積作用，對(duì)于揭示近百年來(lái)該地區(qū)高分辨率的沉積作用和沉積過(guò)程具有獨(dú)特的優(yōu)越性。本研究以長(zhǎng)江口濱外區(qū)現(xiàn)代沉積環(huán)境實(shí)測(cè)資料，結(jié)合CJ0702柱狀樣品為研究對(duì)象，通過(guò)多種實(shí)驗(yàn)測(cè)試手段，包括粒度分析、黏土礦物分析、地球化學(xué)分析等，討論現(xiàn)代長(zhǎng)江口濱外區(qū)沉積環(huán)境及地貌變化特征，并揭示近百年來(lái)研究區(qū)氣候與環(huán)境的變化過(guò)程。 通過(guò)對(duì)定點(diǎn)站位連續(xù)三年動(dòng)力觀測(cè)和濱外區(qū)大面站觀測(cè)的資料分析，表明長(zhǎng)江口濱外區(qū)流速具有明顯的潮周期變化，年際變化不大，與之對(duì)應(yīng)的懸沙含量變化與動(dòng)力變化關(guān)系密切，在一個(gè)潮周期內(nèi)常出現(xiàn)2-4次不等的泥沙峰值，且年際變化也較小。長(zhǎng)江口外地區(qū)沉積動(dòng)力和懸沙含量平面分布特征，由口門(mén)外向東向北逐漸降低，以123°E為界出現(xiàn)明顯的變化，該界限幾乎是長(zhǎng)江沖淡水的影響的東界。近二十年來(lái)長(zhǎng)江口濱外區(qū)沖淤計(jì)算表明，長(zhǎng)江口濱外區(qū)泥沙落淤總量出現(xiàn)減少趨勢(shì)，水下地貌開(kāi)始受到侵蝕。受三峽大壩建設(shè)的影響，，該地區(qū)泥沙落淤總量出現(xiàn)明顯降低，在大壩運(yùn)行相對(duì)平穩(wěn)后出現(xiàn)緩慢增長(zhǎng)。 研究區(qū)表層沉積物類(lèi)型以粉砂、粉砂質(zhì)砂和砂質(zhì)粉砂為主，通過(guò)表層沉積物粒度變化、礦物分析和元素地球化學(xué)分析，表明研究區(qū)主要受到長(zhǎng)江沉積物的影響，但是向東北方向黃河沉積物的影響逐漸增強(qiáng)。 通過(guò)對(duì)CJ0702柱多要素指標(biāo)的分析，表明該地區(qū)近120年來(lái)沉積環(huán)境比較穩(wěn)定，沉積速率能夠達(dá)到近3.11cm/a，不管是巖心沉積物粒度、礦物還是化學(xué)成分，在垂向上變化幅度較小，呈現(xiàn)波動(dòng)性變化。通過(guò)物源分析，CJ0702柱物質(zhì)來(lái)源主要受長(zhǎng)江源物質(zhì)控制，但受到黃河物質(zhì)的一定影響，且近百年來(lái)影響程度有一定的增加趨勢(shì)。 通過(guò)譜分析方法研究表明，近百年來(lái)該地區(qū)粒度及化學(xué)風(fēng)化指數(shù)呈現(xiàn)周期性變化趨勢(shì)，都存在2-8a和16-20a不等的周期性變化趨勢(shì)，與PDO年代際周期變化及ENSO年際周期變化具有良好的對(duì)應(yīng)關(guān)系。通過(guò)敏感粒度組分分析，結(jié)合Zr/Rb值和巖心磁化率，研究近百年來(lái)長(zhǎng)江流域洪水事件在沉積記錄中的響應(yīng)，在沉積記錄中識(shí)別了近二十幾次大洪水。通過(guò)沉積物粒度變化及地球化學(xué)元素含量變化，同時(shí)表明對(duì)流域重大工程建設(shè)和人類(lèi)經(jīng)濟(jì)活動(dòng)，在沉積記錄中同樣有所反應(yīng)。
[Abstract]:The Yangtze River basin brings abundant continental clastic sediments and forms a huge estuarine delta in estuaries and shallow continental shelf areas. The study on the sedimentary evolution process of delta is of great significance to reveal the interaction between land and sea. The depositional rate of the muddy area outside the Changjiang Estuary is relatively high, with relatively stable and continuous sedimentation, which has unique advantages in revealing the high-resolution deposition and the deposition process in this area in the last hundred years. In this study, the measured data of modern sedimentary environment in the offshore area of the Yangtze River Estuary, combined with CJ0702 columnar samples, were studied by various experimental means, including particle size analysis, clay mineral analysis, geochemical analysis, etc. The characteristics of sedimentary environment and geomorphologic change in the offshore area of the Yangtze River Estuary are discussed, and the process of climate and environment change in the study area in the last hundred years is revealed. Through the analysis of the data of dynamic observation at fixed point station for three consecutive years and observation of large surface station in the offshore area, it is shown that the velocity of velocity in the offshore area of the Yangtze River Estuary has obvious tidal cycle variation, but the interannual variation is not obvious. The change of suspended sediment content is closely related to the dynamic change, and the peak value of sediment varies 2-4 times in a tidal cycle, and the interannual variation is relatively small. The sedimentary dynamics and suspended sediment content in the area outside the Yangtze River Estuary gradually decreased from the entrance to the east to the north, with 123 擄E as the boundary, which is almost the eastern boundary of the Yangtze River diluted water. The calculation of scour and siltation in the offshore area of the Yangtze River Estuary in the past two decades shows that the total sediment deposition in the offshore area of the Yangtze River Estuary is decreasing and the underwater geomorphology is beginning to be eroded. Under the influence of the construction of the three Gorges Dam, the total sediment deposition in this area is obviously reduced, and the slow increase occurs after the relatively stable operation of the dam. The main types of surface sediments in the study area are silt, silty sand and sandy silt. Through the grain size change of surface sediment, mineral analysis and element geochemistry analysis, it is shown that the study area is mainly affected by Yangtze River sediments. However, the influence of the Yellow River sediment toward the northeast is increasing gradually. Based on the analysis of the multi-element indexes of CJ0702 column, it is shown that the sedimentary environment in this area is relatively stable in the last 120 years, and the deposition rate can reach 3.11 cm / a, regardless of the grain size, mineral or chemical composition of the core sediment. In the vertical change range is small, showing volatility changes. Through provenance analysis, the material source of CJ0702 column is mainly controlled by the source material of the Yangtze River, but it is influenced by the material of the Yellow River to a certain extent, and the influence degree has a certain increasing trend in the last hundred years. The results of spectral analysis show that the grain size and chemical weathering index of the region have a periodic variation trend in the past hundred years, and there are periodic trends ranging from 2-8 years to 16-20 years. It has a good correspondence with PDO Interdecadal cycle change and ENSO interannual cycle change. The response of flood events in the Yangtze River basin to sedimentary records in the last hundred years has been studied by means of the analysis of sensitive particle size components, combined with Zr/Rb value and core magnetic susceptibility. More than 20 major floods have been identified in the sedimentary records. The variation of sediment grain size and the content of geochemical elements also indicate that the sediment records are also responsive to the major project construction and human economic activities in the basin.
【學(xué)位授予單位】：中國(guó)科學(xué)院研究生院（海洋研究所）
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：P736.21
本文編號(hào)：2308267
[Abstract]:The Yangtze River basin brings abundant continental clastic sediments and forms a huge estuarine delta in estuaries and shallow continental shelf areas. The study on the sedimentary evolution process of delta is of great significance to reveal the interaction between land and sea. The depositional rate of the muddy area outside the Changjiang Estuary is relatively high, with relatively stable and continuous sedimentation, which has unique advantages in revealing the high-resolution deposition and the deposition process in this area in the last hundred years. In this study, the measured data of modern sedimentary environment in the offshore area of the Yangtze River Estuary, combined with CJ0702 columnar samples, were studied by various experimental means, including particle size analysis, clay mineral analysis, geochemical analysis, etc. The characteristics of sedimentary environment and geomorphologic change in the offshore area of the Yangtze River Estuary are discussed, and the process of climate and environment change in the study area in the last hundred years is revealed. Through the analysis of the data of dynamic observation at fixed point station for three consecutive years and observation of large surface station in the offshore area, it is shown that the velocity of velocity in the offshore area of the Yangtze River Estuary has obvious tidal cycle variation, but the interannual variation is not obvious. The change of suspended sediment content is closely related to the dynamic change, and the peak value of sediment varies 2-4 times in a tidal cycle, and the interannual variation is relatively small. The sedimentary dynamics and suspended sediment content in the area outside the Yangtze River Estuary gradually decreased from the entrance to the east to the north, with 123 擄E as the boundary, which is almost the eastern boundary of the Yangtze River diluted water. The calculation of scour and siltation in the offshore area of the Yangtze River Estuary in the past two decades shows that the total sediment deposition in the offshore area of the Yangtze River Estuary is decreasing and the underwater geomorphology is beginning to be eroded. Under the influence of the construction of the three Gorges Dam, the total sediment deposition in this area is obviously reduced, and the slow increase occurs after the relatively stable operation of the dam. The main types of surface sediments in the study area are silt, silty sand and sandy silt. Through the grain size change of surface sediment, mineral analysis and element geochemistry analysis, it is shown that the study area is mainly affected by Yangtze River sediments. However, the influence of the Yellow River sediment toward the northeast is increasing gradually. Based on the analysis of the multi-element indexes of CJ0702 column, it is shown that the sedimentary environment in this area is relatively stable in the last 120 years, and the deposition rate can reach 3.11 cm / a, regardless of the grain size, mineral or chemical composition of the core sediment. In the vertical change range is small, showing volatility changes. Through provenance analysis, the material source of CJ0702 column is mainly controlled by the source material of the Yangtze River, but it is influenced by the material of the Yellow River to a certain extent, and the influence degree has a certain increasing trend in the last hundred years. The results of spectral analysis show that the grain size and chemical weathering index of the region have a periodic variation trend in the past hundred years, and there are periodic trends ranging from 2-8 years to 16-20 years. It has a good correspondence with PDO Interdecadal cycle change and ENSO interannual cycle change. The response of flood events in the Yangtze River basin to sedimentary records in the last hundred years has been studied by means of the analysis of sensitive particle size components, combined with Zr/Rb value and core magnetic susceptibility. More than 20 major floods have been identified in the sedimentary records. The variation of sediment grain size and the content of geochemical elements also indicate that the sediment records are also responsive to the major project construction and human economic activities in the basin.
【學(xué)位授予單位】：中國(guó)科學(xué)院研究生院（海洋研究所）
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：P736.21
【參考文獻(xiàn)】
相關(guān)期刊論文 前10條
1 應(yīng)銘,李九發(fā),萬(wàn)新寧,沈煥庭;長(zhǎng)江大通站輸沙量時(shí)間序列分析研究[J];長(zhǎng)江流域資源與環(huán)境;2005年01期
2 陳麗蓉,申順喜,徐文強(qiáng),李安春;中國(guó)海的碎屑礦物組合及其分布模式的探討[J];沉積學(xué)報(bào);1986年03期
3 趙一陽(yáng),王金土,秦朝陽(yáng),陳毓蔚,王賢覺(jué),吳明清;中國(guó)大陸架海底沉積物中的稀土元素[J];沉積學(xué)報(bào);1990年01期
4 夏小明,楊輝,李炎,李伯根,潘少明;長(zhǎng)江口-杭州灣毗連海區(qū)的現(xiàn)代沉積速率[J];沉積學(xué)報(bào);2004年01期
5 肖尚斌,李安春;東海內(nèi)陸架泥區(qū)沉積物的環(huán)境敏感粒度組分[J];沉積學(xué)報(bào);2005年01期
6 肖尚斌,李安春,蔣富清,尤征,陳莉;近2ka閩浙沿岸泥質(zhì)沉積物物源分析[J];沉積學(xué)報(bào);2005年02期
7 段凌云,王張華,李茂田,潘建明,陳中原,Yishiki Saito,Yutaka kanai;長(zhǎng)江口沉積物~(210)Pb分布及沉積環(huán)境解釋[J];沉積學(xué)報(bào);2005年03期
8 王昕;石學(xué)法;劉升發(fā);王國(guó)慶;喬淑卿;朱愛(ài)美;高晶晶;;近百年來(lái)長(zhǎng)江口外泥質(zhì)區(qū)高分辨率的沉積記錄及影響因素探討[J];沉積學(xué)報(bào);2012年01期
9 谷國(guó)傳;長(zhǎng)江口外水域懸沙分布特征[J];東海海洋;1986年01期
10 謝遠(yuǎn)云;李長(zhǎng)安;王秋良;殷鴻福;;江漢平原近3000年來(lái)古洪水事件的沉積記錄[J];地理科學(xué);2007年01期
本文編號(hào)：2308267
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