發(fā)布時(shí)間：2018-01-12 05:01

  本文關(guān)鍵詞：渤海中南部沉積地球化學(xué)特征和黃河改道事件　出處：《中國(guó)海洋大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 渤海 表層沉積物 黃河改道 沉積記錄 元素地球化學(xué)

【摘要】：渤海是三面被陸地環(huán)繞的半封閉陸表海，其沉積作用受到以黃河為代表的周邊河流的強(qiáng)烈影響。歷史上，黃河曾經(jīng)游蕩于黃海、渤海之間，每次改道對(duì)渤海而言都是一次重大的沉積事件，深刻改變渤海沉積過(guò)程。基于表層沉積物和沉積物巖芯的地球化學(xué)研究，從現(xiàn)代沉積狀態(tài)反演歷史時(shí)期的沉積演變，可為深入了解渤海沉積物源匯作用提供科學(xué)支持。 本研究通過(guò)對(duì)渤海表層及柱狀沉積物中粒度、常量元素和微量元素含量組合及變化特征的系統(tǒng)分析，探討了表層沉積物的空間分布及其影響因素，揭示了1855年黃河改道事件的沉積學(xué)記錄，闡明黃河改道前后渤海沉積環(huán)境效應(yīng)。主要得到以下研究成果： 渤海中南部表層沉積物的粒度特征總體表現(xiàn)為研究區(qū)中、南部較細(xì)，東北部和西北部較粗，分別對(duì)應(yīng)黃河物質(zhì)、遼東淺灘和灤河沉積物的特征。 表層沉積物中的常量元素Si和Na的空間分布呈現(xiàn)出北高南低的相似特點(diǎn)；Al、Fe等5種元素的空間分布特征類似；Ca的分布與上述元素組合均有所差異。表層沉積物中的V、Cu等5微量元素在空間分布上具有相似的趨勢(shì)；Sr、Zr和Ba元素則各自有自己分布上的特點(diǎn)。 依據(jù)主量元素和微量元素組成，研究區(qū)可以清晰地分成四個(gè)分區(qū)：一區(qū)和二區(qū)都以低含量的Si、Sr、Ba和Zr，高含量的Al、Ca以及V、Cu等微量元素為特征，總體上均以黃河來(lái)源的物質(zhì)為主，但在萊州灣沿岸沖刷物及水動(dòng)力環(huán)境的影響下有所差異；三區(qū)主要以異常高含量的Mn、P及較高含量的Sr、Ba和Zr為特征，體現(xiàn)了遼東淺灘水動(dòng)力強(qiáng)勁、明顯偏氧化的的沉積環(huán)境特點(diǎn)；四區(qū)以高Si、低Al以及微量元素含量都較低為特征，代表了灤河來(lái)源為主的沉積物。 渤海中部沉積物巖心的粒度、地球化學(xué)組成上可以明顯地分成兩段，上段粒度特征以平均粒徑細(xì)、分選好及單峰形態(tài)、元素含量方面以高Ni、Zn及低Mn、Sr、Ba和Zr為特征，下段粒度特征以平均粒徑粗、分選差及雙峰形態(tài)、元素含量方面以低Ni、Zn及高M(jìn)n、Sr、Ba和Zr為特征。這種差異是由于1855年黃河改道所致。 黃河改道入海渤海使得渤海中部沉積物來(lái)源、沉積動(dòng)力環(huán)境發(fā)生明顯的改變，改道前為濱—淺海沉積環(huán)境，，沉積物來(lái)源復(fù)雜，波浪作用強(qiáng)，屬于氧化環(huán)境，有利于底棲生物發(fā)育；改道后為前三角洲、三角洲前緣環(huán)境，沉積物來(lái)源單一，三角洲的進(jìn)積作用占主導(dǎo)，偏向還原環(huán)境，底棲生物不發(fā)育。
[Abstract]:Bohai is a semi enclosed sea surface on three sides surrounded by land, the strong influence of deposition is represented by the Yellow River river. Historically, the Yellow River has been wandering in the Yellow Sea, Bohai, each diversion is a major depositional event for Bohai, profound change Bohai geochemical deposition process. Study on surface sediments and sediment cores based on sedimentary evolution from modern sedimentary state inversion period, can provide scientific support for the in-depth understanding of Bohai sediment source sink.
Based on the size of Bohai and surface sediments, analysis of major and trace elements content combination and change characteristic, discusses the spatial distribution and influencing factors of surface sediments, reveals the sedimentary records of 1855 the Yellow River diversion events, clarify the diversion of the Yellow River before and after the Bohai sedimentary environment effects. The following are the main research results:
The grain size characteristics of the overall performance of the surface sediments from the central and southern Bohai as the study area, the south is fine, northeast and northwest are thick, corresponding the Yellow River material, characteristics of the Liaodong shoal and the Luanhe River sediments.
The major elements in the surface sediments of Si and the spatial distribution of Na showed similar characteristics of North High South low; Al, the spatial distribution characteristics of 5 kinds of elements such as Fe Ca and the like; the distribution of elements in the surface sediments are different. V, Cu and other 5 trace elements have the similar trend in spatial distribution on Sr, Zr and Ba; the element of their respective characteristics of the distribution.
On the basis of major elements and trace elements, the study area can be clearly divided into four zones: a region and a two region with low content of Si, Sr, Ba and Zr, the high content of Al, Ca and V, for the characteristics of trace elements such as Cu, on the whole are in the Yellow River source material, but the difference in the effect of scouring and the Gulf of Laizhou coast hydrodynamic environment; three areas mainly in the abnormally high content of Mn, P and high content of Sr, Ba and Zr characteristics, reflects the Liaodong shoal water power strong, obviously oxidation characteristics of sedimentary environment; four areas with high Si and low Al and the contents of trace elements are lower as the characteristic, represents the main source of the Luanhe River sediments.
The size of central Bohai sediment cores, geochemical composition can be clearly divided into two sections, with the average grain size characteristics of the upper fine particle size, good sorting and single peak pattern, with high content of Ni, Zn and low Mn, Sr, Ba and Zr characteristics, grain size characteristics of lower segment with average particle diameter, sorting and the Shuangfeng morphology, element content in low Zn and high Ni, Mn, Sr, Ba and Zr. The characteristic of this difference is due to the diversion of the Yellow River in 1855.
The Yellow River, the center of Bohai Bohai sea sediment sources, sediment environment changed before diversion to shore neritic sedimentary environment, sedimentary source complex, strong wave action, which belongs to the oxidizing environment conducive to benthic development; after the diversion for predelta, delta front, delta sediment source is limited. Progradation dominates, bias reduction environment and benthic organisms are not developed.

【學(xué)位授予單位】：中國(guó)海洋大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：P343.1;P736.4

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本文編號(hào)：1412765