本文選題：射陽(yáng)海岸　切入點(diǎn)：~(210)Pb和~(137)Cs定年　出處：《南京師范大學(xué)》2015年碩士論文

【摘要】：射陽(yáng)海岸是江蘇中部沿海典型粉砂淤泥質(zhì)平原海岸,也是近現(xiàn)代快速淤積的海岸之一,其面積廣闊且不斷淤漲的灘涂是我國(guó)東部地區(qū)潛力最大、最重要的后備土地資源,它開(kāi)發(fā)與利用能夠緩解人增地減矛盾、實(shí)現(xiàn)耕地總量動(dòng)態(tài)平衡,滿足經(jīng)濟(jì)和社會(huì)發(fā)展對(duì)海岸港口資源、土地資源和生物資源的開(kāi)發(fā)提出的更高的要求。同時(shí),近年來(lái)人類圍墾筑堤等活動(dòng)影響著海岸的淤漲速度；工業(yè)、農(nóng)業(yè)、交通運(yùn)輸、生活和社會(huì)活動(dòng)產(chǎn)生的大量污染物排入河流、湖泊和沿岸海域,致使海岸生態(tài)惡化。本文針對(duì)射陽(yáng)海岸動(dòng)力環(huán)境復(fù)雜、物質(zhì)來(lái)源豐富等特點(diǎn),通過(guò)采集射陽(yáng)海岸潮灘柱狀樣沉積物和挖取剖面,以及對(duì)沉積物剖面樣品的進(jìn)行210pb和137Cs測(cè)年分析、相互驗(yàn)證并估算射陽(yáng)海岸沉積速率,確定沉積年代；通過(guò)粒度、重礦物及重金屬含量測(cè)定,多指標(biāo)分析沉積物質(zhì)來(lái)源、解釋沉積速率的變化過(guò)程；最后將放射性核素確定的沉積物年代與特定的環(huán)境下海岸重金屬污染事件相聯(lián)系,以探明射陽(yáng)海岸沉積物中重金屬的不同沉積時(shí)段內(nèi)分布特征,判別重金屬來(lái)源、污染歷史并初步評(píng)價(jià)了研究區(qū)的重金屬污染程度。結(jié)果顯示：(1)通過(guò)放射性核素210pb和137Cs測(cè)年法得出210pbex比活度自表層至底層呈現(xiàn)鋸齒狀波動(dòng)的階段性趨勢(shì),充分考慮沉積物堆積過(guò)程中受人類活動(dòng)的影響,并得出射陽(yáng)海岸一百年以來(lái)的沉積速的變化過(guò)程；結(jié)合137Cs的測(cè)年結(jié)果中存在的幾個(gè)明顯的計(jì)年時(shí)標(biāo)：1954年、1963年和1986年蓄積峰,推算出1954年以來(lái)海岸沉積速率；210Pb和137Cs結(jié)果相互驗(yàn)證,可識(shí)別該區(qū)域的沉積年代,且確定年代具有可靠性和準(zhǔn)確性。(2)根據(jù)210pbexCRS計(jì)年模型,得出射陽(yáng)海岸柱芯SY-1和SY-2平均沉積速率分別為1.03 cm/a和2.04cm/a,并以此劃分出射陽(yáng)海岸淤積的四個(gè)階段：A：自然淤漲階段(1920～1956),沉積速率低且相對(duì)穩(wěn)定；B：淤積調(diào)整期階段(1957年～1990年)海岸沉積物沉積速率出現(xiàn)緩慢上升過(guò)程；C：快速促淤期(1991年～2000年),沉積速率迅速增加,增幅最大,受人類活動(dòng)影響劇烈；D：淤積波動(dòng)期(2001年～2013年),平均沉積速率最大,呈鋸齒狀波大幅度波動(dòng),受自然因素和人類活動(dòng)雙重作用。(3)根據(jù)137Cs測(cè)年結(jié)果可以計(jì)算出柱芯SY-1和SY-2自1954年以來(lái)、1963年以來(lái)和1986年以來(lái)射陽(yáng)海岸平均沉積速率分別為0.88cm/a和1.69cm/a、0.87cm/a和1.72cm/a、1.13cm/a和2.22cm/a,結(jié)果與前人研究基本一致。(4)利用沉積物粒度參數(shù)的分析可知,研究區(qū)主要以細(xì)粉砂和粗粉砂為主,說(shuō)明射陽(yáng)海岸主要為細(xì)顆粒沉積物堆積區(qū)。柱狀樣剖面從底部向上均表現(xiàn)出先變細(xì)再變粗的總體趨勢(shì),結(jié)合年代推出主要與上世紀(jì)80年代末期至90年代初期和本世紀(jì)初期大規(guī)模墾荒種植、圍海養(yǎng)殖等人類活動(dòng)密切相關(guān)。(5)本區(qū)重礦物主要為赤褐鐵礦、磁鐵礦、綠簾石、石榴子石、鋯石、金紅石、電氣石等17種,總體含量普遍較低,均低于1%,隨深度的變化相對(duì)較小,但大致趨勢(shì)為由上至下重礦物含量逐漸減少；形態(tài)上以柱狀為主,僅極少量的云母片狀；以穩(wěn)定礦物為主的重礦物組成,表明該海岸水動(dòng)力相對(duì)較強(qiáng),物源穩(wěn)定。其中,不穩(wěn)定性的角閃石出現(xiàn)在第4層位,表明80～90年代射陽(yáng)海岸水動(dòng)力條件稍弱,與該時(shí)期沉積物快速淤積相一致。(6)總體來(lái)看,沉積物中重金屬元素變化趨勢(shì)相似,除了Cr和Mn元素外,其它重金屬元素含量垂向變化為隨著深度增加出現(xiàn)先增加后減少、或比較穩(wěn)定地波動(dòng)變化；并且在2005和1991左右出現(xiàn)的富集現(xiàn)象與該時(shí)段沉積物粒徑細(xì)化、水動(dòng)力較弱以及沉積速率加快的變化具有同步性。其中Al、Fe、Zn、Mg、Mn、Ni、Cu、Pb元素主要來(lái)自于自然物質(zhì)風(fēng)化,而Cr、Hg和As元素的積累主要反映了人類活動(dòng)的影響。最后運(yùn)用地積累指數(shù)法初步評(píng)價(jià)得出,除了Hg元素屬于輕度污染,其他元素均狀況良好。
[Abstract]:Sheyang coast is the central coast of Jiangsu typical silt plain coast, one of the coast is modern rapid siltation, the vast area and continuous siltation beach is the largest potential in the eastern region of China, the most important reserve land resources development and utilization, it can alleviate the increasing population contradiction, realize the dynamic balance of the total arable land and meet the economic and social development of coastal port resources, land resources and biological resources put forward higher requirements. At the same time, the activities of reclamation embankment in recent years affect coastal sediment rate; industry, agriculture, transportation, life and social activities of the large amount of pollutants discharged into rivers, lakes and coastal the sea coast, resulting in deterioration of ecological environment. According to the Sheyang coast complex dynamic environment, rich material source and other characteristics, through the acquisition of Sheyang coastal tidal flat core sediments and digging section, And determined 210Pb and 137Cs on sediment samples, mutual authentication and estimation of Sheyang coast deposition rate, determined by particle size, deposition time; Determination of heavy minerals and heavy metal content, multi index analysis source of sedimentary materials, explain the change of the deposition rate of the process; finally determine the radionuclide ages of sediments and the particular environment under the coastal heavy metal pollution incidents linked, distribution of different sedimentary periods to determine heavy metals in the sediments of the Sheyang coast, distinguishing the sources of heavy metal pollution history, and a preliminary evaluation of the degree of heavy metal pollution in the study area. The results showed that: (1) by radionuclide 210Pb and 137Cs dating method of trend from the surface to the specific activity of 210Pbex the bottom is jagged fluctuations, considering the sediment accumulation under the influence of human activities in the process, and obtains the Sheyang coast one hundred The change process of depositing velocity years; several combined 137Cs dating results in significant annual time scales: 1954, 1963 and 1986 accumulation peak, calculate since 1954 coastal deposition rate; 210Pb and 137Cs results of mutual authentication, which can identify the regional sedimentary years, and determine the age and reliability accuracy. (2) according to the 210pbexCRS model, the average sedimentation rate of Sheyang coastal cores from SY-1 and SY-2 were 1.03 cm/a and 2.04cm/a, and then divided into four stages: the Sheyang coast siltation A: natural silting up stage (1920~1956), low deposition rate and relatively stable; B: sediment adjustment stage (1957 ~ 1990) coastal sedimentary rate slow rise process; C: rapid siltation period (1991 to 2000), the deposition rate increases rapidly, the largest increase, human activities influence sharply; D: deposition The fluctuation period (2001 ~ 2013), the average maximum deposition rate, jagged wave fluctuations, influenced by both natural factors and human activities. (3) according to the 137Cs dating results can calculate the column core SY-1 and SY-2 since 1954, and since 1963 1986 since the average sedimentation rate of Sheyang coast and 0.88cm/a respectively. 1.69cm/a, 0.87cm/a and 1.72cm/a, 1.13cm/a and 2.22cm/a, and the results of previous studies are basically the same. (4) the analysis of sediment grain size parameters show that the study area mainly fine sand and coarse silt, Sheyang coast for fine grain sediment accumulation area. The column sample section from the bottom to show the first thinning change trend of crude, with the launch of the main and the last century, the late 80s to early 90s and the beginning of this century large-scale cultivation, aquaculture reclamation and other human activities are closely related. (5) the heavy Minerals are mainly magnetite, hematite and limonite, epidote, garnet, zircon, tourmaline, Jin Hongshi, 17, the overall content is generally low, lower than 1%, relatively small changes with depth, but the general trend is from top to bottom heavy mineral content gradually reduced; form in columns, only a few mica flake; heavy minerals in stable minerals composition, shows that the coastal water power is relatively strong, stable source. Among them, amphibole instability appeared in fourth layers, that 80~90's Sheyang coast hydrodynamic condition is weaker, with the period of rapid siltation of sediment is consistent. (6) overall, the trend of heavy metals the change in sediment is similar, except for Cr and Mn elements, other heavy metal elements in vertical change with the increase of the depth first increased and then decreased, or relatively stable fluctuations; and in the 2005 and 1991 or so Now with the time accumulation of sediment grain size refinement, with the simultaneous changes and weak hydrodynamic deposition rate. The Al, Fe, Zn, Mg, Mn, Ni, Cu, Pb elements are mainly from natural weathering material, while Cr, Hg and As elements accumulation mainly reflects the influence of human activities finally. The geoaccumulation index was used to preliminary evaluation, in addition to the Hg elements belong to light pollution, other elements are in good condition.

【學(xué)位授予單位】：南京師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：P736.21;X55

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 潘少明，王雪瑜;海南島洋浦港現(xiàn)代沉積速率[J];沉積學(xué)報(bào);1994年02期

2 張忍順,陸麗云,王艷紅;江蘇海岸侵蝕過(guò)程及其趨勢(shì)[J];地理研究;2002年04期

3 于文金;鄒欣慶;;王港潮灘重金屬Pb、Zn和Cu積累規(guī)律及污染評(píng)價(jià)[J];地理研究;2007年04期

4 劉秀娟;高抒;汪亞平;;淤長(zhǎng)型潮灘剖面形態(tài)演變模擬:以江蘇中部海岸為例[J];地球科學(xué)(中國(guó)地質(zhì)大學(xué)學(xué)報(bào));2010年04期

5 張振克;李彥明;孟紅明;王萬(wàn)芳;何華春;蔣松柳;;江蘇圓陀角附近潮灘沉積巖芯粒度變化及其環(huán)境意義[J];第四紀(jì)研究;2008年04期

6 朱曉強(qiáng),吳小根,王愛(ài)軍,顧江卉,張建新;江蘇射陽(yáng)縣灘涂資源的開(kāi)發(fā)利用及發(fā)展規(guī)劃[J];地域研究與開(kāi)發(fā);2003年02期

7 張曉祥;王偉瑋;嚴(yán)長(zhǎng)清;晏王波;戴煜暄;徐盼;朱晨曦;;南宋以來(lái)江蘇海岸帶歷史海岸線時(shí)空演變研究[J];地理科學(xué);2014年03期

8 王楠;;鹽城市灘涂資源開(kāi)發(fā)的現(xiàn)狀·效果與問(wèn)題[J];安徽農(nóng)業(yè)科學(xué);2014年29期

9 曲偉秀;張鷹;劉燕春;;圍墾對(duì)射陽(yáng)河口海岸地形的影響[J];河海大學(xué)學(xué)報(bào)(自然科學(xué)版);2012年02期

10 楊雪舞;珠江口黃茅海河口灣泥沙來(lái)源和運(yùn)移過(guò)程分析[J];海洋通報(bào);1993年06期

，

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