本文選題：空間多尺度變化 + 常、微量元素��； 參考：《中國地質(zhì)大學(xué)》2016年博士論文

【摘要】：元素地球化學(xué)是示蹤物源與沉積環(huán)境的重要手段,對(duì)于資源勘查與環(huán)境評(píng)價(jià)具有重要的指示意義。本文基于南海西北近海獲得的880個(gè)站位的表層沉積物常、微量元素以及3251個(gè)站位粒度數(shù)據(jù),利用因子克里格分析和粒徑趨勢(shì)分析等方法,開展空間不同尺度的元素地球化學(xué)、沉積動(dòng)力學(xué)研究,旨在揭示沉積物在不同空間尺度上的自然變化規(guī)律與人為活動(dòng)影響特征。主要取得以下幾點(diǎn)認(rèn)識(shí)：利用表層沉積物粒度數(shù)據(jù),分析了砂-粉砂-粘土的含量及分布特征,結(jié)合沉積物粒徑參數(shù)特征及水動(dòng)力條件,將研究區(qū)劃分為四類沉積環(huán)境：(Ⅰ)近岸粗H粒砂質(zhì)沉積區(qū)；(Ⅱ)北部灣中部至海南島西部以及粵西沿岸至海南島東北部海域的泥質(zhì)區(qū)； (Ⅲ)瓊州海峽及東西出口砂質(zhì)沉積區(qū)；(Ⅳ)殘留沉積區(qū)�；诙嘣亟y(tǒng)計(jì)分析的沉積物粒徑趨勢(shì)分析顯示,局部尺度上(半徑約33km)研究區(qū)大致存在A-R等18個(gè)較小范圍的粒徑“匯聚中心”,分布于各類型的沉積環(huán)境中,反映了河流輸入、地形、海流等多種因素的控制作用。區(qū)域尺度上(半徑80km),大致存在A'-Ⅰ’等9個(gè)較大范圍的粒徑“匯聚中心”,空間上與Ⅰ、Ⅱ型沉積環(huán)境較為一致，且匯聚中心空間展布具有明顯的方向性,顯示了區(qū)域性環(huán)流的控制作用。根據(jù)常微量元素的相關(guān)性分析,選擇Al2O3,Fe2O3,MgO,MnO,TiO2,P2O5,K2O,Na2O與Mz組(常量元素組),Ni,Zn,Pb,Cu,Cd，，Cr與Mz組(微量元素組),CaO-Sr組,SiO2-砂組等四組組分分別進(jìn)行了因子克里格分析。結(jié)果顯示,常量元素組、微量元素組、SiO2-砂均存在三種尺度的空間結(jié)構(gòu)：塊金尺度、變程為70km球狀結(jié)構(gòu)(局部尺度)和變程為160km的球狀結(jié)構(gòu)(區(qū)域尺度)。而CaO-Sr則表現(xiàn)為塊金尺度、變程為120km球狀結(jié)構(gòu)(局部尺度)和變程為250km的球狀結(jié)構(gòu)(區(qū)域尺度),明顯不同于其他元素的空間結(jié)構(gòu),歸因于CaO的海洋自生屬性。常量元素組在局部、區(qū)域尺度上,均主要受控于陸源粘土組分以及水成Fe-Mn氧化物組分。局部尺度上,兩種組分具有類似的空間分布特征,主要分布在河流的入海口及其近海的海灣、港口等Ⅰ類近岸的粗粒沉積環(huán)境,與粒徑趨勢(shì)匯聚中心A,E,G,J,N,P相對(duì)應(yīng),顯示了陸源河流輸入的控制作用；Fe-Mn氧化物組分還受到河流入海后堿性、氧化的海水影響產(chǎn)生自生沉淀,導(dǎo)致了Fe-Mn氧化物組分的空間分布比陸源粘土類組分更為接近陸地。區(qū)域尺度上,陸源粘土類組分呈現(xiàn)環(huán)陸地分布、向海降低的特征,高值區(qū)分布于Ⅰ型近岸粗粒沉積環(huán)境,推測(cè)為海平面上升時(shí)期的陸源粘土組分沉積在低海平面時(shí)粗粒組分之上形成的。Fe-Mn組分高值區(qū)主要分布于Ⅱ型泥質(zhì)區(qū)以及Ⅲ型瓊州海峽東出口等水動(dòng)力較強(qiáng)的地區(qū),對(duì)應(yīng)了區(qū)域尺度上粒徑匯聚中心A',B',C',G',H',I',指示了區(qū)域性環(huán)流與氧化還原環(huán)境的控制作用。Si02-砂組與CaO-Sr組分別代表了陸源硅質(zhì)粗粒組分和海洋生物組分,兩者空間分布的尺度效應(yīng)不明顯,Si02主要分布在Ⅰ、ⅢH型高能的沉積環(huán)境,反映了水動(dòng)力條件控制作用；CaO主要分布在遠(yuǎn)離陸地的較深海域,與水深正相關(guān)分布,指示了水深對(duì)生物類組分的控制。微量元素組在局部尺度上主要受人為活動(dòng)的影響,Pb,Cd是人為活動(dòng)影響的指標(biāo)元素,分別約8.4%和6.5%的站位富集系數(shù)已達(dá)到中等富集-顯著富集的程度,表明Pb,Cd可能已受到人為污染,且高值區(qū)分布的防城港、廉州灣、江洪灣、�？跒场⒄拷�、雷州灣、博鰲港、八所港等人類活動(dòng)密集、工業(yè)或交通發(fā)達(dá)的地區(qū)是可能污染區(qū)。微量元素在區(qū)域尺度上主要為陸源粘土類吸附組分,空間分布上表現(xiàn)出自陸地向海增加的特征,高值區(qū)主要分布于Ⅱ類泥質(zhì)沉積環(huán)境,對(duì)應(yīng)了區(qū)域尺度上粒徑匯聚中心A',B',C',G',H',I',與區(qū)域性環(huán)流的影響有關(guān)。Cd獨(dú)特的地球化學(xué)性質(zhì)使其在區(qū)域尺度上成為一個(gè)獨(dú)立的主成分,高值區(qū)主要分布在瓊州海峽、海南島西南沿岸海域以及漠陽江南部海域,推測(cè)是低海平面時(shí)近源的陸源碎屑沉積以及海陸相互作用的結(jié)果。綜上所述,研究區(qū)自然的陸源組分具有局部尺度(70km)和區(qū)域尺度(160km)兩種尺度的空間變化；局部尺度上,中小型河流的陸源輸入是最主要的控制因素,水深、地形、海流、氧化還原環(huán)境對(duì)沉積物的搬運(yùn)、沉積具有重要作用；區(qū)域尺度上,海平面升降以及區(qū)域性海洋環(huán)流是主控因素。海洋生物組分主要表現(xiàn)為區(qū)域尺度上(250km)的空間變化,水深是主要的控制因素。人為影響組分則表現(xiàn)為局部尺度(70km)上的空間變化,主要受控于局部人為污染源的輸入。
[Abstract]:Elemental geochemistry is an important means of tracer source and sedimentary environment. It has important directive significance for resource exploration and environmental evaluation. Based on the surface sediments, trace elements and 3251 station size data of 880 stations in the northwest offshore of the South China Sea, the methods of factor Craig analysis and particle size trend analysis are used. In order to reveal the characteristics of natural variation and human activities in different spatial scales, the study of the geochemical and sedimentary dynamics of different spatial scales aims to reveal the characteristics of the natural variation and human activities in different spatial scales. The characteristics of diameter parameters and hydrodynamic conditions are divided into four types of sedimentary environments: (I) the coarse H granular sandy sedimentary area in the near shore; (II) the mud area in the middle of the north bay to the west of Hainan Island and the coastal area of the west of Guangdong to the northeast of Hainan Island; (III) the Qiongzhou Strait and the eastern and Western sand sediment area; (IV) residual sedimentary area. The statistical analysis of sediment grain size trend analysis shows that there are roughly 18 smaller size "convergence centers" of A-R in the study area on the local scale (radius about 33km), which are distributed in various types of sedimentary environments, reflecting the control effect of various factors such as river input, terrain and sea current. The region scale (radius 80km) is roughly A'- I 'and other 9 larger size distribution centers, which are more consistent with the sedimentary environment of type I and II, and have obvious directionality in the distribution center space, showing the control of regional circulation. According to the correlation analysis of the constant trace elements, Al2O3, Fe2O3, MgO, MnO, TiO2, P2O5, K2O, Na2O and Mz group (constant element) Group Ni, Zn, Pb, Cu, Cd, Cr and Mz group (microelement group), CaO-Sr group, SiO2- sand group and other four groups respectively, the factor Craig analysis. The results show that the constant element group, microelement group, SiO2- sand have three kinds of spatial structure: the bulk gold scale, the variable range is the 70km spherical structure (local scale) and the spherical structure of 160km. While CaO-Sr is a massive gold scale, the variable range is 120km spherical structure (local scale) and the spherical structure of 250km (regional scale), which is obviously different from the spatial structure of other elements, which is attributed to the marine authigenic attribute of CaO. The constant element group is mainly controlled by the land source clay components and water on the local and regional scales. Fe-Mn oxide components. On the local scale, the two components have similar spatial distribution characteristics, mainly distributed in the river entrance to the sea and its Offshore Bay, the port and other near shore coarse sedimentary environment, corresponding to the grain size trend convergence center A, E, G, J, N, P, showing the control effect of the land source river input; Fe-Mn oxide component. It is also influenced by the alkaline and oxidizing seawater after the river enters the sea, which produces autogenic precipitation, which leads to the spatial distribution of Fe-Mn oxide components closer to the land than the land-based clay components. The high value area of.Fe-Mn components formed on the low sea level coarse clay components at low sea level is mainly distributed in the type II argillaceous zone and the east exit of type III Qiongzhou Strait, which corresponds to the A', B', C', G', H', I', indicating regional circulation and oxidation, which indicates regional circulation and oxidation. The control effect of the reduction environment.Si02- sand group and CaO-Sr group represent the land source siliceous coarse grain components and the marine biocomponents respectively. The scale effect of the spatial distribution is not obvious. Si02 mainly distributes in the sedimentary environment of type I, III H high energy, which reflects the control of hydrodynamic conditions; CaO is mainly distributed in the deep sea away from the land, and the water is mainly distributed in the water. The deep positive correlation distribution indicates the control of the water depth to the biological components. The microelement group is mainly influenced by human activities on the local scale. Pb and Cd are the index elements of the human activities. The enrichment coefficient of the stations of about 8.4% and 6.5%, respectively, has reached the degree of medium enrichment and significant enrichment, indicating that Pb and Cd may have been polluted by human beings and are high. Fangchenggang, Lian Zhou Bay, Jiang Hong Wan, Haikou Bay, Zhanjiang port, Leizhou Bay, Leizhou Bay, Boao port, and eight ports are concentrated in human activities. The industrial or traffic developed areas are possible pollution areas. The trace elements are mainly land-based clay adsorption components on the regional scale, and the space distribution shows the characteristics of increasing from land to sea, and high value area owners It should be distributed in type II argillaceous sedimentary environment, corresponding to A', B', C', G', H', I' at regional scale. The unique geochemical properties of.Cd related to the influence of regional circulation on the regional scale make it an independent principal component on the regional scale, and the high value area is mainly distributed in the Qiongzhou Strait, the southwestern coastal waters of Hainan Island and the south of the south of the south of desert Yang. It is presumed to be the result of the land-based clastic deposition and sea land interaction of the near source at low sea level. To sum up, the natural terrestrial components of the study area have two spatial variations of the local scale (70km) and the regional scale (160km); on the local scale, the land source input of the small and medium rivers is the most important control factor, the depth of water and the land. Shape, current and redox environment play an important role in sediment transport and deposition; on regional scale, sea level fluctuation and regional ocean circulation are the main controlling factors. The marine biological components are mainly the spatial variations on the regional scale (250km), the water depth is the main control factor. The human influence group is represented as the local scale (70 The spatial variation of KM is mainly controlled by the input of local anthropogenic pollution sources.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2016
【分類號(hào)】：P736.41

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