發(fā)布時(shí)間：2018-06-20 02:14

  本文選題：東海內(nèi)陸架 + 高分辨沉積記錄　； 參考：《中國海洋大學(xué)》2014年博士論文

【摘要】：IODP計(jì)劃（2013~2023）中的第一個科學(xué)主題中明確指出：海底的沉積物巖芯提供了過去氣候變化的記錄，能夠在空間和時(shí)間尺度上更好理解地球系統(tǒng)演變過程，，地質(zhì)記錄能夠幫助我們檢驗(yàn)預(yù)測未來氣候模型的準(zhǔn)確性。東海是東亞季風(fēng)、西太平洋邊界流共同影響下的海域，接受來自長江、黃河以及眾多中小型河流的大量陸源物質(zhì)輸入，具有很高的沉積速率，使得該處成為開展高分辨沉積記錄及其對多尺度氣候變化響應(yīng)研究的重要選區(qū)。本研究以東海內(nèi)陸架閩浙沿岸泥質(zhì)沉積區(qū)為研究對象，開展了沉積學(xué)和地球化學(xué)的超高分辨沉積記錄的綜合研究，揭示了泥質(zhì)沉積記錄中存在的高頻振蕩現(xiàn)象和隱形沉積“年紋”，利用沉積紋層進(jìn)行精細(xì)的年代標(biāo)定，建立了該區(qū)域近200年來的超高分辨沉積記錄模式，并與東亞季風(fēng)、ENSO與PDO指數(shù)進(jìn)行耦合研究，探討沉積層序中的高頻波動對年際、年代際氣候振蕩的響應(yīng)機(jī)制。該研究結(jié)果將為東亞季風(fēng)影響下的陸架區(qū)超高分辨沉積記錄研究提供新的途徑，并為客觀評價(jià)東海內(nèi)陸架海洋環(huán)境演變中的自然因素、人類活動的貢獻(xiàn)和演變趨勢提供科學(xué)依據(jù)。 論文首先探索了超高分辨沉積記錄的沉積學(xué)指標(biāo)，即巖芯的X-ray影像灰度指標(biāo)和Corescanner巖芯元素掃描指標(biāo)。通過對東海內(nèi)陸架表層沉積物和四根沉積物巖芯X-ray影像灰度的研究表明：1）沉積物的灰度值是沉積物密度、結(jié)構(gòu)和構(gòu)造等屬性的綜合體現(xiàn),但是受沉積物中的含水量的影響明顯，兩者呈現(xiàn)出明顯的負(fù)相關(guān)關(guān)系，并據(jù)此提出了灰度的含水量校正公式。經(jīng)過校正后的沉積物灰度值與沉積物的粒度、砂+粉砂的百分含量有著良好的一致性，可以近似看作巖芯的粒度替代性指標(biāo)；依據(jù)灰度對東海陸架沉積物進(jìn)行了分區(qū)，能很好地反映了該區(qū)的沉積環(huán)境。2）對沉積物巖芯進(jìn)行X-rayCorescanner連續(xù)巖芯掃描研究表明：巖芯中沉積物的含水量和干密度均對X-ray巖芯掃描元素分析結(jié)果產(chǎn)生影響，即為壓實(shí)效應(yīng)，并得到了該區(qū)壓實(shí)效應(yīng)的校正公式，據(jù)此可以對Corescanner結(jié)果進(jìn)行壓實(shí)效應(yīng)的校正。評價(jià)了針對東海內(nèi)陸架泥質(zhì)沉積區(qū)X-ray core scanner元素測試能力，將其分成四類，其中I類元素分析結(jié)果可信度高、可以直接作為含量對待，II類具有重要的參考價(jià)值，III類具有一定參考價(jià)值，而IV類無參考價(jià)值。 對取自東海內(nèi)陸架的4根巖芯18、C0702、DH6-1、DH7-2，系統(tǒng)地開展了沉積物巖芯的X-ray影像灰度、巖芯Corescanner元素掃描、粒度分析以及放射性同位素測定，建立了東海內(nèi)陸架近200年來高分辨沉積記錄。通過經(jīng)驗(yàn)?zāi)B(tài)分解-最大熵譜分析法(EMD-MESA)及功率譜分析等方法對高分辨沉積記錄進(jìn)行了周期性分析，識別了該區(qū)域存在的隱形年紋或年代紋；利用沉積紋層定年并經(jīng)210Pb、137Cs測年驗(yàn)證，建立起了該區(qū)域內(nèi)近200年來高精度的年代標(biāo)尺，揭示了該研究區(qū)內(nèi)沉積層序三種高頻波動模式：(i)年內(nèi)及年尺度準(zhǔn)周期變化；(ii)年際尺度的準(zhǔn)周期變化(~2-8年)；(iii)年代際尺度準(zhǔn)周期變化。不同位置的沉積巖芯的高頻波動模式略有差別。 將東海內(nèi)陸架沉積層序的高頻波動模式與東亞季風(fēng)、ENSO及PDO指數(shù)進(jìn)行耦合研究，結(jié)果表明巖芯18存在的年內(nèi)及年尺度準(zhǔn)周期變化是長江輸沙量的周期性變化的結(jié)果，其余三根巖芯C0702、DH6-1及DH7-2中沉積記錄中高頻波動的準(zhǔn)兩年周期與東亞季風(fēng)的準(zhǔn)2年周期變化有著顯著的關(guān)系；四根巖芯中沉積記錄的年際高頻波動與ENSO的(2~8年)周期有著良好的響應(yīng)關(guān)系，該周期性波動是由ENSO振蕩影響了東亞冬季風(fēng)的強(qiáng)度、進(jìn)而改變了該區(qū)的海洋沉積動力環(huán)境和沉積物搬運(yùn)沉積過程所產(chǎn)生；該區(qū)沉積記錄中的年代際的波動與PDO指數(shù)變化有著良好的響應(yīng)關(guān)系，分析認(rèn)為是PDO相位發(fā)生轉(zhuǎn)變時(shí)引起東亞大陸的表層風(fēng)發(fā)生異常，并導(dǎo)致東亞冬季風(fēng)強(qiáng)度發(fā)生變化，進(jìn)而影響了該區(qū)的沉積動力環(huán)境和沉積過程，最終導(dǎo)致了沉積層序中的年代際周期的形成。
[Abstract]:The first scientific theme in the IODP program (2013~2023) clearly points out that the sediment cores from the sea floor provide a record of the past climate change, which can better understand the evolution of the earth's system in space and time, and the geological record can help us test the accuracy of the prediction of future climate models. The sea area under the common influence of the flat ocean boundary flows, receiving a large amount of terrestrial material input from the Yangtze, the Yellow River and many small and medium rivers, has a high deposition rate, making it an important selected area for the study of high resolution sedimentary records and their response to multi-scale climate change. The integrated study of sedimentary and geochemistry of ultrahigh resolution sedimentary records has been carried out. The high frequency oscillations and the "annual lines" of the stealth deposits in the sedimentary records are revealed, and the fine dating of the sedimentary layers is used to establish the ultra high resolution sedimentary record model for the region in the past 200 years. The East Asian monsoon, coupled with the ENSO and PDO index, explores the response mechanism of high frequency fluctuations to interannual and Interdecadal Climatic Oscillations in sedimentary sequences. The results will provide a new way for the study of ultrahigh resolution sedimentary records in the continental shelf area under the influence of East Asian monsoon, and to objectively evaluate the nature of the marine environment evolution in the inland shelf of the East China Sea. Factors provide a scientific basis for the contribution and evolution of human activities.
In this paper, the sedimentological indexes of ultrahigh resolution sedimentary records are first explored, that is, the gray index of X-ray image and the scanning index of Corescanner core elements in the core. Through the study of the X-ray image grayscale of the surface sediments of the East China Sea and the X-ray image of the core of the sediments, 1) the gray value of the sediments is the density, structure and structure of the sediments. There is a clear negative correlation between the water content in the sediment and the obvious negative correlation between the water content in the sediment, and the gray level water content correction formula is put forward accordingly. The corrected sediment grayscale value has good consistency with the grain size of the sediment and the content of sand and silt. It can be considered approximately as the grain size of the core. The subregion of the sediments in the East China Sea shelf is subdivided according to the gray level, which can well reflect the sedimentary environment.2 in the area. The study of X-rayCorescanner continuous core scanning for the sediment core shows that the water content and dry density of the sediments in the core are all influenced by the results of the analysis of the X-ray core scanning elements, that is, the pressure effect is effective. The correction formula for the compaction effect of the area can be obtained. According to this, the compaction effect of Corescanner results can be corrected. The testing ability of the X-ray core scanner element in the muddy sediment area of the East China Sea is evaluated and divided into four categories, in which the analysis results of I elements are highly credible and can be treated directly as content, and II classes have heavy weight. The reference value of the III class has certain reference value, while the IV class has no reference value.
4 cores from the inland shelf of the East China Sea, 18, C0702, DH6-1, DH7-2, have systematically carried out the X-ray image gray level of the sediment core, the core Corescanner element scanning, the particle size analysis and the radioisotope determination. The high resolution sedimentary records of the East China Sea continental shelf for nearly 200 years have been established. The empirical mode decomposition maximum entropy spectrum analysis (EMD-MESA) has been established. With the method of power spectrum analysis, the periodic analysis of high resolution sedimentary records is carried out, and the stealth annual or chronology of the region is identified. By using the sedimentary layer for dating and verifying by 210Pb, 137Cs dating, the high precision chronology ruler in the region for nearly 200 years has been established, and three high-frequency fluctuations in the sedimentary sequence in this study area have been revealed. Model: (I) the annual and annual scale quasi periodic changes; (II) the interannual scale quasi periodic change (~2-8); (III) the interdecadal scale quasi periodic changes. The high-frequency fluctuation patterns of the sedimentary cores at different positions are slightly different.
The high frequency fluctuation model of the sedimentary sequence of the East China Sea continental shelf is coupled with the East Asian monsoon, ENSO and PDO index. The results show that the annual and annual quasi periodic changes of the core 18 are the result of the periodic variation of the sediment transport in the Yangtze River, and the quasi Biennial period of the high frequency fluctuation in the other three core cores C0702, DH6-1 and DH7-2. There is a significant relationship between the quasi 2 year periodic changes in the East Asian monsoon; the interannual high-frequency fluctuation recorded in the four cores has a good response relationship with the ENSO (2~8 year) cycle. The periodic fluctuation affects the East Asian winter monsoon intensity by the ENSO oscillation, and then changes the marine sedimentary dynamic environment and sediment transport deposition in this area. The interdecadal fluctuations in the depositional records of the region have a good response to the changes in the PDO index. It is believed that the change of the surface wind in the East Asian continent is caused by the transition of the PDO phase, which leads to the change in the East Asian winter wind intensity, and then affects the sedimentary dynamic environment and the deposition process in the region, and ultimately leads to the guidance of the sedimentary process. The formation of the interdecadal cycle in the depositional sequence is caused.
【學(xué)位授予單位】：中國海洋大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2014
【分類號】：P736.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 程鵬,高抒,李徐生;激光粒度儀測試結(jié)果及其與沉降法、篩析法的比較[J];沉積學(xué)報(bào);2001年03期

2 徐方建;李安春;肖尚斌;萬世明;劉建國;張永超;;末次冰消期以來東海內(nèi)陸架古環(huán)境演化[J];沉積學(xué)報(bào);2009年01期

3 張喜林;范德江;劉明;王亮;;沉積物巖芯X光片圖像灰度數(shù)值及其影響因素[J];沉積學(xué)報(bào);2012年02期

4 劉紅;何青;Gert Jan Weltje;陳吉余;;長江入海泥沙的交換和輸移過程——兼論泥質(zhì)區(qū)的“泥庫”效應(yīng)[J];地理學(xué)報(bào);2011年03期

5 黃榮輝,吳儀芳;The Influence of ENSO on the Summer Climate Change in China and Its Mechanism[J];Advances in Atmospheric Sciences;1989年01期

6 肖尚斌,李安春,陳木宏,劉敬圃,蔣富清,李鐵剛,謝強(qiáng),向榮,陳忠;近8ka東亞冬季風(fēng)變化的東海內(nèi)陸架泥質(zhì)沉積記錄[J];地球科學(xué);2005年05期

7 劉永強(qiáng)，丁一匯;ENSO事件對我國季節(jié)降水和溫度的影響[J];大氣科學(xué);1995年02期

8 汪品先,翦知　;尋求高分辨率的古環(huán)境記錄[J];第四紀(jì)研究;1999年01期

9 夏威嵐,薛濱;吉林小龍灣沉積速率的~(210)Pb和~(137)Cs年代學(xué)方法測定[J];第四紀(jì)研究;2004年01期

10 楊作升;陳曉輝;;百年來長江口泥質(zhì)區(qū)高分辨率沉積粒度變化及影響因素探討[J];第四紀(jì)研究;2007年05期

本文編號：2042459