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1.
本文对长江与黄河口黏土粒级沉积物主微量元素的地球化学特征进行了研究。结果表明:长江相对富集Al、K、Fe、Ti等常量元素以及Cr、V、Li、Zn、Ni和Rb等微量元素,黄河以高Ca、Sr和Ba为特征;长江沉积物中稀土元素含量高于黄河沉积物,长江与黄河黏土粒级沉积物中稀土元素的分馏程度相同,均具有轻稀土元素富集、重稀土元素亏损的右倾的球粒陨石标准化配分模式,上陆壳标准化配分模式为中稀土元素富集,黄河沉积物的Ce负异常和Eu正异常程度较长江沉积物偏弱。长江沉积物中元素含量变化较大,而黄河沉积物中元素含量较为稳定。黏土粒级沉积物的稀土元素更接近其物源区,2μm的黏土粒级沉积物中的REE可以作为判识长江与黄河沉积物的地球化学指标。ΣREE、δCe可以作为长江、黄河入海沉积物的判别指标。长江与黄河黏土粒级沉积物的地球化学特征受源区岩石类型、化学风化、水动力分选等因素的控制。化学风化引起河流沉积物相对其源岩发生地球化学分异,水动力分选使矿物在不同粒级沉积物中富集,从而引起地球化学组成在不同粒级沉积物中的分异。  相似文献   

2.
南黄海表层沉积物微量元素地球化学特征   总被引:6,自引:0,他引:6  
分析了在南黄海采集的295个站位的表层沉积物样品的微量元素含量和500个站位的粒度参数,研究了南黄海沉积物微量元素含量、平均粒径和判别函数的分布特征及微量元素、沉积物类型和平均粒径的相关性。南黄海沉积物微量元素分布由于物质来源和与沉积物类型相关性的不同,表现出明显不同的分布规律:Sr分布与黄河、长江和生物碎屑碳酸盐的贡献有明显关系;Ba分布与黄河、锦江物质供给有关;东部Rb元素分布反映了韩国河流沉积物对南黄海东部的影响;Co分布反映了长江物质的运移方向。Ba和Cu与沉积物类型相关性不明显,不受沉积物粒度控制;Sr、Co、Rb则可以用于区分黄河、长江和韩国河流沉积物的来源。  相似文献   

3.
为探讨闽江下游及河口区表层沉积物中元素组成、分布规律,用X射线荧光法分析了研究区域表层沉积物中11种微量元素的含量,并简要讨论了其分布特征和影响因素.分析结果表明,研究区沉积物中元素Ba含量最高,平均为515 mg/kg,元素Ga最低,平均为7.54 mg/kg,11种元素按含量由高到低排列是Ba、Rb、Zr、Sr、Cr、V、Zn、Nb、Y、Cu、Ga;元素变异系数介于0.17~1.05之间,最大为Zr,最小为Ba.被测元素含量均呈现出沿河道向河口递增的趋势,部分元素表现出南、北港下游含量高于上游的分布特征,显示人类活动的影响.元素含量高值与Si/Al比值所反映出的沉积物细颗粒区域相对应.沉积物微量元素含量与花岗岩成分相近,与石英砂岩存在较大差别.研究区域沉积物与长江、黄河和珠江沉积物相比,Ba、Rb两种元素含量差异相对较小,4条河流Ba约500mg/kg、Rb约100 mg/kg,其余元素在闽江沉积物中的含量相对较低,元素Zn、Cu差异最大.Cu、Zn和Cr 3种重金属元素相对以往分析结果较低.被测元素中V、Y、Zr、Nb 4种元素彼此相关性较强,相关系数均在0.8以上.被测元素均与Si/Al比值呈负相关关系,其中Rb、Ba、Sr关系相对密切,相关系数分别为:-0.887 2,-0.886 5和-0.885 8.通过沉积物微量元素分布及其影响因素探讨的分析表明,元素分布反应出在该区域物源和气候等特征条件影响下物理、化学风化的结果,同时受到沉积物粒度、人为活动和潮汐等因素的共同作用.  相似文献   

4.
山东半岛东部海域表层沉积物元素组成及物源指示意义   总被引:1,自引:1,他引:0  
窦衍光  李军  杨守业 《海洋学报》2012,34(1):109-119
通过对山东半岛东部海域表层沉积物常量、微量元素、有机碳(TOC)以及碳酸盐(CaCO3)等指标的分析,研究了该海域表层沉积物元素组成特征及其控制因素,并对物质来源进行了探讨。结果表明,山东半岛东部海域表层沉积物元素的平均组成与上陆壳(UCC)相比Al,K,Na,Mg,Fe,Ca,Cu和Zn等元素,相对较低,而Mn,Co,Ni,Cr以及REE元素含量较高,Si和Ti与UCC的含量相当。研究区砂粒级沉积物轻重稀土分异明显,(La/Yb)N值与韩国河流的非常相近;其余粒级沉积物LREE分异较弱,标准化曲线与黄河沉积物的具有相似性。研究区沉积物的元素含量主要受控于源岩组成,存在明显的"粒级效应"。除此之外,Fe-Mn氧化物、生物碳酸盐等因素对元素组成产生一定影响。沉积物物源判别结果显示,山东半岛近岸及其东南部沉积物主要来源于黄河,该区域沉积物分布受山东半岛沿岸流及近岸潮流影响。研究区东北部为残留砂,其沉积物元素组成特征与朝鲜半岛和鸭绿江沉积物组成相近,表明研究区东北部砂质区沉积物代末次冰期低海平面时可能由朝鲜半岛或鸭绿江供应。  相似文献   

5.
长江、黄河入海沉积物中元素组成的对比   总被引:3,自引:0,他引:3  
使用X射线荧光分析仪对取自长江大通站(包括部分南京段)和黄河利津站入海沉积物进行了分析,研究了25种元素的含量特征及它们在长江和黄河里的差异,并与前人研究成果作了比较.研究表明,长江、黄河中的沉积物存在较明显差异,黄河沉积物中明显富集Ca,Sr,Si等元素;长江沉积物中明显富集Al,Fe,Ti,Mn,Cu,Zn,Pb,Rb,P,V等元素.这与2条河流流域的地质背景、气候带特征、风化程度以及人为活动影响关系密切.与前人研究结果相比,2类沉积物中重金属元素的含量有明显增加的趋势,但是用Al标准化之后发现只有部分重金属元素含量有所增加.重金属的变化可能与近年来中国工业快速发展及两河流域污染物质的排放增加有关.  相似文献   

6.
依据山东半岛东部海域79个站位表层沉积物微量元素测试结果,分析了研究区微量元素含量空间分布特征,识别了沉积物来源,探讨了其控制因素和沉积物输运模式。结果表明,研究区表层沉积物微量元素中Ba和Sr平均质量比最高,分别为465μg/g和198μg/g;Ba含量整体呈中间低、四周高的趋势; Sr整体呈近岸高、离岸低的分布特征。除Ba和Sr外, Cr、Cu、Ni、Pb、Co和V含量空间分布特征基本一致,整体呈近岸低、离岸高的分布特征。通过m(Cr)/m(V)-m(Ni)(m表示元素质量比,μg/g)散点图判别,研究区沉积物主要来源于黄河物质,南部可能有少量长江物质输入。微量元素的分布受物源和粒度效应的控制。研究区微量元素除Ba、Sr外,其余元素与平均粒径呈正相关, Sr元素则与平均粒径呈负相关性,Ba与沉积物粒径无明显相关性。黄海沿岸流携带黄河物质绕过成山头后在研究区发生沉积,同时受到北上黄海暖流的阻隔,在研究区南部发生混合扩散后沉积。研究成果对于补充完善山东半岛泥质区的物源和输运机制具有重要意义。  相似文献   

7.
长江与黄河沉积物中粘土矿物及地化成分的组成   总被引:32,自引:6,他引:32  
采用X射线衍射物相分析、ICP-AES成分分析等方法对长江与黄河沉积物中粘土矿物、地化成分组成进行了研究,结果表明:在粘土矿物组成上,长江、黄河沉积物都为伊利石+绿泥石+高岭石+蒙皂石组合,但长江沉积物以伊利石含量高(约70%)、蒙皂石含量低(约5%-7%)、伊利石/蒙皂石比值大于8为特征;黄河型沉积物则以伊利石含量低(约60%)、蒙皂石含量高(约15%)、伊利石/蒙皂石比值小于6为特征。在小于0.016mm粒级内残渣态地化成分组成上,TiO2、CaO、Na2O、MgO、Fe2O3、Sr、Ba、Li、Co和V在长江、黄河两类沉积物中差别明显。黄河沉积物中碳酸盐的含量通常都为长江的2倍以上,而在小于0.005mm(7.5φ)粒级中黄河沉积物碳酸盐的含量约为长江的9倍。  相似文献   

8.
分析了南海西南海域表层沉积物的微量元素和稀土元素组成,结果表明,这些沉积物与大陆上地壳相比,具有相对低的Zr、Sc、V、Nb、Hf、Th、REEs含量,而Co、Cu、Ni、Ta、Rb、Cs、Sr、Ba的含量稍高;深海区表层沉积物比陆坡区具有较高的Co、Zr、Sc、V、Nb、Hf、Ta、Th和REEs,陆坡区表层沉积物相对高的生物碎屑组分对这些元素起到了一定程度的稀释作用。因子分析和相关分析显示绝大部分微量元素和稀土元素主要受陆源组分的控制,Th、Cr、Co、Sc、Nb、Zr、Hf和REEs等不活动元素之间的比值特征,并没有受到风化作用、海流搬运作用和海洋自生组分稀释作用的影响,较好地保存了源岩的化学组成特征。因此,南海西南海域表层沉积物的La/Sc、Th/Sc、Th/Cr、Th/Co比值和稀土配分曲线特征,指示这些沉积物的源岩具有陆壳成分的特点,以长英质岩石为主,缺乏深源的基性和超基性岩,火山碎屑物质成分很低,其源区主要为南海西部的印支大陆。陆架区和深海区表层沉积物具有十分相近的微量元素和稀土元素组成特征,指示它们的碎屑物质来源较为相同。  相似文献   

9.
对双台子河口潮滩上所采集沉积物样品的微量元素含量进行了测试分析,研究其空间分布特征、元素相关性以及元素组合特征,探索了微量元素在河口潮滩上的迁移富集规律及其控制因素。结果表明:潮滩沉积物中Cu、Pb、Zn元素富集,V元素流失;除Ti、Ba、Sr、Zr外,其余11种元素均表现为高潮滩比中低潮滩含量高;R型因子分析识别出3个微量元素组合,分别是Mn、Rb、Co、Cu等为代表的亲铁亲铜的元素组合,Sr、Ba等与含钾矿物有关的元素组合和Nb、Y等与细粒黏土有关的元素组合。  相似文献   

10.
闽江钻孔沉积物微量元素地球化学研究   总被引:1,自引:0,他引:1  
河流沉积物微量元素特征对指示沉积演化历史、沉积环境及沉积物的物质来源具有十分重要的示踪作用。闽江福州段540cm的沉积物微量元素比值(Rb/Sr和Sr/Ba)和稀土元素地球化学特征,敏锐地指示了沉积环境从河流快速转变为沼泽的突变点,同时,也清楚地指示了不同沉积环境下的物源变化。受控于闽江流域丰富的岩浆岩和稀土资源以及呈酸性的福建土壤和闽江水体,闽江钻孔沉积物REE明显高于上地壳、长江和黄河,与福建土壤最为接近。经过球状陨石和北美页岩标准化之后,闽江钻孔沉积物稀土元素分配模式呈右倾型,与长江和黄河沉积相比具有更好的轻稀土富集。δEu负异常和δCe正异常非常显著,并且与∑REE密切相关,表明它们均受到源区环境变化和搬运作用的控制。  相似文献   

11.
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.  相似文献   

12.
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.  相似文献   

13.
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths.  相似文献   

14.
海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明:土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。  相似文献   

15.
Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.  相似文献   

16.
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.  相似文献   

17.
《海洋学报(英文版)》2014,(8):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,  相似文献   

18.
19.
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.  相似文献   

20.
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.  相似文献   

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