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1.
近50 a来杭州湾冲淤变化规律与机制研究 总被引：6，自引：4，他引：2
使用杭州湾1959-2010年的水下地形图, 结合过去数十年来长江入海水沙量和钱塘江河口段冲淤变化状况, 分析了近50 a来杭州湾在长江入海泥沙量锐减和治江围涂等人类活动作用下的冲淤变化规律及其物理机理。结果表明, 乍浦以上区域近50 a来处于较显著的淤积状态, 且有自上向下发展的趋势, 这种淤积主要是由于钱塘江河口治江缩窄工程所引起的;湾内地形发生了局部调整, 部分小型潮流槽脊系统趋于消亡, 地形趋于平坦化, 湾口北部2003年以后有转淤为冲的趋势, 这与长江入海泥沙量锐减和该区域围垦工程等因素有关;1959-2003和2003-2010年两个时段, 湾内泥沙淤积的年平均值分别为0.91×108和1.66×108 m3。对于整个钱塘江河口系统而言, 即自杭州湾湾口至钱塘江河口段的闸口断面, 长江入海泥沙量减少所产生的影响尚不明显, 2003年以后泥沙淤积速率甚至有所上升。杭州湾近50 a的冲淤变化是人为强烈干预下的大流域-河口系统响应与中小流域-河口系统响应的调整结果。 相似文献
2.
南海北部湾东部海域表层沉积物地球化学特征 总被引：2，自引：1，他引：1
通过对南海北部湾东部海域61 个站位表层沉积物粒度和地球化学组成的相关分析和因子分析,探讨了其空间分布特征、元素相关性以及元素组合特征, 揭示了元素在区域上的分布规律和主控因素。结果表明: 绝大多数常微量元素具有相似的平面分布特征, 而MnO、Zr、CaO 和Sr 空间变异系数较大,在部分区域出现了异常高值, 表明其沉积环境受到正常陆源沉积以外其他因素的影响。元素和Al2O3的比值分布特征表明, 广西和海南岛近岸沉积物主要由陆源碎屑沉积组成, 在潮汐和近岸径流作用下,由近岸向远海输送; 而研究区西部海域沉积物主要为来自红河的物质。元素相关分析和因子分析结果表明, 研究区表层沉积物中绝大多数常微量元素主要受沉积物粒度的控制; CaO 和Sr 含量主要受生物活动活跃程度控制; Zr 含量分布主要受控于源区母岩矿物组成以及自源区的搬运距离; 而MnO 含量则受陆源、海底热液以及自生作用等多种来源共同影响。 相似文献
3.
长江与黄河沉积物元素组成及地质背景 总被引：46，自引：2，他引：46
长江与黄河表层沉积物常量及微量元素组成特征明显不同。长江相对富Ｋ、Ｆｅ、Ａｌ等常量元素及绝大多数微量元素,且元素含量变化大;而黄河相对富Ｃａ、Ｎａ、Ｓｒ、Ｂａ、Ｔｈ、Ｚｒ、Ｈｆ等少数元素,元素含量变化较小;长江流域广泛分布的中酸性岩浆岩及复杂的源岩与强烈的化学风化作用决定了长江沉积物的特征元素组成及元素含量变化大的特点;而黄土高原的黄土化学成分与强烈的物理风化作用决定了黄河沉积物的特征元素组成。Ｃｕ、Ｚｎ、Ｓｃ、Ｔｉ、Ｆｅ、Ｖ、Ｎｉ、Ｃｒ、Ｃｏ、Ｂｅ、Ｌｉ等元素可较好地用来区分长江与黄河沉积物,以探索长江与黄河的入海物质在海域中的混合及扩散问题 相似文献
4.
-In order to avoid prescribing open boundary condition on the upstream side of the Hangzhou Bay, in numerical simulation of the tides and residual currents of the Bay, a 1-D model for the Qiantang River is connected to the 2-D model for the Hangzhou Bay. The harmonic constants of diurnal constituent [ (K1 O1)/2],semidiurnal constituent (M2) and shallow water constituent (M4) are obtained. The results produced by the combined model are in better agreement with the observed ones than those produced solely by the original 2-D model. The combined model gives much more reliable results for tide-induced residual water level and current. 相似文献
5.
对取自渤海湾的307个表层沉积物进行了元素测试和粒度分析。渤海湾表层沉积物的常微量元素呈现4种组合:富集于粗粒沉积区的SiO_2、Na_2O亲碎屑元素组合;富集于细粒沉积区的以Al_2O_3和重金属元素为代表的亲黏土元素组合;与缺氧环境有关的MnO、V、TOC元素组合和与河流输入有关的陆源CaO、TiO_2元素组合。粒度粗细主导了渤海湾元素含量分布的整体格局;海域河流物源供应不同较大影响了渤海湾南部(富Na_2O、CaO和SiO_2)和北部(富Ba和P_2O_5)在元素含量上的差异;高流速潮流对海底的冲刷再分配导致曹妃甸南侧Sr、Ca元素的条带状富集异常;有机质在细粒沉积区的富集导致缺氧环境的形成和K_2O、Mn、V、自生黄铁矿的海洋自生化学沉积;人类活动导致以Pb为代表的重金属污染在河流入海口、港口及沿岸海域的元素分布异常;曹妃甸沙坝内侧的泻湖(海洋钙质生物沉积)与沙坝外侧水下岸坡(陆源碎屑沉积)的截然不同的物源,导致了独特地貌沉积环境下元素分布的局部差异。 相似文献
6.
The contents of seven major components (TiO2, Fe2O3, MgO, CaO, Na2O, K2O and P2O5) and 15 trace elements (Sc, V, Cr, Ni, Cu, Sr, Y, Zr, Ba, La, Ce, Nd, Eu, Yb and Th) were determined by ICP-AE spectrometry
in 27 samples of manganese nodules, micronodules as well as abyssal clay collected by dredging from an area of nearly 1,9802
nautical miles in the central Clarion-Clipperton abyssal plain at a depth of about 4,500 m. Statistical analyses were used
to compare among individual as well as pooled datasets, in addition to different indicators such as La/Th, Ni/Cu and LREE/HREE
ratios for the Clarion-Clipperton samples, as well as between these and corresponding values for the upper continental crust
(UCC), North America Shale Composite (NASC), and igneous Indian and Pacific Mid-Ocean Ridge Basalts (MORBs). The results show
significant correlations between major components in the Clarion-Clipperton samples and Pacific Ocean MORB, whereas trace
elements (excepting Ni and Cu) correlate better with the UCC and NASC. There is also depletion in LREEs, together with a Ce
negative anomaly for all Clarion-Clipperton samples. The nodule, micronodule and abyssal clay datasets each reveal typical
clusters of components such as P2O5 and Y, La, Nd, Eu, Tb, or Ni and Cu. Compared to abyssal clay, the nodule as well as micronodules show significant enrichment
in Ni and Cu; nevertheless, an essentially constant Ni/Cu ratio indicates that all samples come from the sediment surface.
The distributions of major components as well as trace elements for the Clarion-Clipperton samples present, to different degrees,
characteristics common to both the upper continental crust and Mid-Ocean Ridge Basalt, strongly implying a hydrothermal origin,
most probably from East Pacific Rise material transported by the Pacific North Equatorial Current. 相似文献
7.
Impact of trace metals on denitrification in estuarine sediments of the Douro River estuary,Portugal 总被引：1，自引：0，他引：1
Denitrification influences the nitrogen budget in estuaries by removing fixed nitrogen from the inorganic pool; rates are dependent on both geological and geographic conditions as well as increasing anthropogenic impacts. In this study the effects of copper (Cu), chromium (Cr), zinc (Zn), cadmium (Cd) and lead (Pb), on the denitrification pathway were evaluated in subtidal and intertidal sediments of the Douro River estuary. Dinitrogen, N2O and NO2− production rates were measured in triplicate slurries of field samples under different treatments of metal concentrations. Results demonstrated that similar metal amendments led to different site responses for denitrification, suggesting that variations in sediment properties (metal concentrations, grain size, organic matter content, etc.) and/or differences in denitrifying community tolerance modulate the level of metal toxicity. Denitrifying communities in subtidal muddy sediments were not affected by increasing concentrations of metals. In contrast, intertidal sandy sites revealed high sensitivity to almost all trace metals tested; almost complete inhibition by Cr (95%) and Cu (85%) was observed for 98 and 79 μg per gram of wet sediment respectively, and by Zn (92%) at the highest concentration added (490 μg per gram of wet sediment). Moreover, the addition of trace metals stimulated N2O and NO2− accumulation in intertidal sandy (Zn, Cu, Cr and Cd) and muddy sediments (Cu and Zn), demonstrating a pronounced inhibitory effect on specific steps within the denitrification enzymatic system. In summary, the results obtained suggest that, according to the type of estuarine sediment, trace metals cannot only reduce total N removal from an estuary via denitrification but also can enhance the release of N2O, a powerful greenhouse gas. 相似文献
8.
根据湄州湾表层沉积物70个样品18个化学成分的分析结果,得出:本海区沉积物属于海相陆源物,其中细颗粒主要来自台湾海峡,粗颗粒来自当地陆域;化学成分含量按聚类分析,可归为三组:粘土矿物组、碳酸盐组和分散组,微量元素Zn,Cr,Be,Cu和Sr的含量与地壳及台湾海峡相似,但低于胶州湾,说明该海区污染很少。 相似文献
9.
珠江口底质常、微量元素分析结果表明, 富含Si、Al、K、Mg、Fe和Ti等元素的陆源物质构成本区沉积物主体, 主要元素氧化物平均含量分别为SiO261.16%, Al2O314.74%, Fe2O35.72%, TiO20.88%, MgO1.84%, K2O2.63%, CaO2.70%, CaCO34.79%。底质元素含量与沉积物粒度组成关系密切, 主要元素Al2O3、MgO、Fe2O3、TiO2以及微量元素Cu、Pb、Zn、Cr、V、Co、Ni、Ba在西北部近岸区以及伶仃洋中部细颗粒沉积区内富集; 而SiO2、CaO、Zr、Sr则在西南部和东南部粗颗粒沉积区富集。控制本区沉积物地球化学特征的因素主要有物质来源、沉积环境、水动力条件、沉积物粒度、矿物组成以及元素自身地球化学性质等。 相似文献
10.
为探讨北黄海表层沉积物中常量元素分布特征,并进一步分析其控制因素和物质来源,以常量元素为依托,对304个站位表层沉积物常量元素含量分布特征及控制因素进行统计分析,结果表明:沉积物中SiO2、Al2O3、Fe2O3、MgO、K2O、P2O5、TiO2七种元素含量的空间分布具有明显的区域性。其中,SiO2、K2O具有相似的空间分布;Al2O3、Fe2O3、MgO、P2O5、TiO2具有相似的空间分布,但与SiO2、K2O的分布趋势相反;CaO、MnO、Na2O在区域内分布较为均匀,未显示出明显的高低变化趋势。聚类分析显示,表层沉积物的常量元素分布主要受粒度效应的控制。主因子分析提取出3种控制常量元素分布的主成分,分析表明,粒度控制效应、源区风化作用和不同物源输入是影响表层沉积物常量元素空间分布的主要因素,贡献累计方差总和达77.12%。以K2O、CaO、TiO2为指标,通过FD函数识别出北黄海不同海域内的主要物质来源,其主要物源包括黄河、鸭绿江和黄海暖流携带的长江物质。对北黄海沉积物物质来源进行分析,不仅在海洋矿产资源勘探、航道开发、沿岸港口建设与整治等方面具有实际意义,而且在认识海洋环境变迁等方面同样具有理论意义。 相似文献
11.
环境因素对杭州湾中型浮游动物群落结构的控制作用 总被引：1，自引：0，他引：1
A quarterly study of mesozooplankton community structure and environmental variables in the Hangzhou Bay was conducted to examine the response of mesozooplankton community to the variation of water mass and environmental condition. The southeast coast of China is a typical region under the intensive influence of Asia monsoon and freshwater discharge from rivers. The water mass and environmental condition of the Hangzhou Bay, which were influenced by the interaction of currents, freshwater discharge of the Qiantang River and Changjiang River Plume, showed significant seasonal variation. Our results showed that both biomass and abundance were significantly higher in summer((247.7±148.8) mg/m~3 and(350.9±215.6) ind./m~3, respectively)than those in other seasons. Four eco-geographical regions were divided based on the cluster analysis of zooplankton community of the Hangzhou Bay throughout the year, except for winter. Monsoon and the dissolved inorganic nitrogen(DIN) input from freshwater discharge of the Qiantang River and Changjiang River resulted in temporal and spatial variations of environmental gradient in the Hangzhou Bay, which significantly influenced the structure of mesozooplankton community. Redundancy analysis(RDA) indicated that the mesozooplankton community structure was strictly correlated with the DIN gradient, while salinity gradient showed a weak influence in the Hangzhou Bay. 相似文献
12.
杭州湾潮汐特征时空变化及原因分析 总被引：2，自引：2，他引：0
杭州湾是世界著名的强潮河口湾,一直是研究的热点。基于杭州湾口内外实测潮汐资料,对杭州湾潮汐特征及时空变化进行了系统分析,包括高潮位、低潮位、平均潮位、潮差、涨潮历时以及天文潮变化,同时分析了20世纪80年代以来潮汐特征变化的原因。结果表明:最近50年来,杭州湾年平均高潮位和海平面抬高,潮差增大;澉浦年平均低潮位抬高,涨潮历时缩短,浅海分潮增大;钱塘江河口治江缩窄是造成杭州湾潮汐变化的主要因素;浙江和邻近海域的涉海工程可能是造成浙江沿海海平面上升的主要原因之一。 相似文献
13.
Pore water aliquots were taken with an in situ close interval sampler: the “Peeper”.We report here the pore water concentration profiles of TCO2, SO4, TH2S, Ca and the trace metals Mn, Cu, Pb, Cd and Cr from sediments of a relatively polluted area, the Villefranche Bay, on the French Riviera (close to Nice).We investigated the major ion concentrations in order to establish geochemical mass balances of organic matter oxidation. ΔTCO2/ΔSO4 was <−2.0, reflecting the precipitation of calcite as confirmed by the calcium profile. Reduction of sulfate led to increasing sulfide concentrations with depth.Trace metal interstitial water concentrations decreased from 63 to 5 nM, 18 to 4 nM and 6.6 to less than 2 nM for Cu, Pb and Cr, respectively. Cd showed a different pattern with top and deep values of 0.7 nM and a minimum of 0.27 nM.Thermodynamic calculations were performed which suggest the potential formation of mineral phases such as sulfides. 相似文献
14.
东海陆架晚第四纪沉积物化学成分及物源示踪 总被引：11，自引：0，他引：11
东海陆架EA1孔和EA5孔沉积物化学成分变化范围较大。与东海陆架表层沉积物相比，钻孔沉积物的Si,Al,Mg,Mn,Ti,P,Ba,Zr,Co,Ni,Cu,Zn,Cr明显偏高，而Fe,Na,Ca,Sr,Li,U明显偏低，与全球大陆地壳化学组成相比，钻孔沉积物的Si,Li,Rb,Ba,Th,Zr,Hf,Cu,Zn,Pb偏高，而Al,Na,Ca,Mg,Fe,Mn,Ti,P,Sr,U,Co,Ni,V,Cr偏低，钻孔沉积物的化学成分在垂向上具有明显变化，主要受岩性和沉积环境的控制，钻孔沉积物中元素的富集因子（EF）均小于10，接近于1，表明钻孔沉积物主要来自大陆地壳，一些元素因分异或外来物质加入而富集，一些元素则因分异带出而亏损，钻孔沉积物源区的DF值判别表明，钻孔沉积物与现代黄河，长江沉积物均有亲缘关系，可能是在末次冰期最盛期，由于气候带南移，干旱区域扩大，在古长江搬运沉积物中类似现今黄河沉积物的干旱组分明显增加，从而导致了地球化学示踪结果的长江与黄河双重性，或者说古气候的变化导致了古长江搬运物质成分的变化。 相似文献
15.
We present new major element, ICP-MS trace element, and Sr–Nd–Pb isotope data of basalts from four locations along the Carlsberg Ridge (CR), northern Indian Ocean. The basalts are low-K tholeiites with 7.52–9.51 wt% MgO, 49.40–50.60 wt% SiO2, 0.09–0.27 wt% K2O, 2.55–2.90 wt% Na2O, and 0.60–0.68 Mg#. Trace element contents of the basalts show characteristics similar to those of average normal MORB, such as LREE depleted patterns with (La/Sm)N ratio of 0.55–0.69; however, some samples are enriched in large-ion lithophile elements such as K and Rb, suggesting probable modification of the mantle source. Poor correlations between the compatible elements [e.g. Ni, Cr, and Sr (related to olivine, clinopyroxene and plagioclase, respectively)] and the incompatible elements (e.g. Zr and Y), and positive correlations in the Zr versus Zr/Y and Nb versus Nb/Y plots suggest a magmatic evolution controlled mainly by mantle melting rather than fractional crystallization. Our results extend the CR basalt range to higher radiogenic Pb isotopes and lower 143Nd/144Nd. These basalts and basalts from the northern Indian Ocean Ridge show lower 143Nd/144Nd and higher 87Sr/86Sr values than those of the depleted mantle (DM), defining a trend towards pelagic sediment composition. The Pb isotopic ratios of basalts from CR 3–4°N lie along the compositional mixing lines between the DM and the upper continental crust. However, the low radiogenic Pb of basalts from CR 9–10°N lie on the mixing line between the DM and lower continental crust. Since the Pb isotopic ratio of MORB would decrease if the source mantle was contaminated by continental lithospheric mantle, we suggest that CR contains continental lithospheric material, resulting in heterogeneous mantle beneath different ridge segments. The continental lithospheric material was introduced into the asthenosphere before or during the breakup of the Gondwana. These results support the long-term preservation of continental material in the oceanic mantle which would significantly influence the isotopic anomaly of the Indian Ocean MORB. 相似文献
16.
ECOMSED模式在杭州湾海域流场模拟中的应用 总被引：13，自引：0，他引：13
针对杭州湾独特的喇叭型强潮河口湾的特点,基于Blumberg等(1996)的ECOMSED模式,引入动边界技术,建立杭州湾三维动边界的潮流模型.模型以正交曲线坐标下三维非线性水动力方程为基本方程,应用Mellor和Yamada的2.5阶湍流闭合模型计算紊动黏滞系数,嵌入Grant和Madsen的底边界层模型考虑波浪对底部应力的作用,采用干湿网格法模拟潮流漫滩过程;综合考虑径流,风应力,密度流和M2,S2,K1,O1四个主要分潮和M4,S4,MS4三个浅水分潮的作用,从而提高杭州湾潮流模拟的精度.通过验潮站调和常数和多次海流连续观测资料的验证,表明该文建立的模型可以更好的用于杭州湾流场的预报模拟. 相似文献
17.
胶州湾沉积物地球化学特征的初步研究 总被引：2，自引：1，他引：2
关于胶州湾沉积物的地球化学研究,迄今未有报道,本文拟做一尝试.文中揭示了胶州湾表层沉积物的化学成分特征,对部分微量元素的地球化学特征进行了初步探讨,并对比分析了胶州湾同其它海湾沉积物在地球化学特征方面的异同点. 相似文献
18.
罗纳河中悬浮物质的痕量元素的研究 总被引：5，自引：0，他引：5
于1989年5月－1990年4月间,在罗纳河下游近河口处进行每月一次为期间个月的样品采集工作,并且样品用HNO3－HF－HCIO4湿法消化后,用原子吸收分光光度法测定了悬浮颗粒物中的Co,Cr,Cu,Mn和Pb含量。结果表明,在不同月份之间悬浮物中的痕量元素组成具有显著地差别,其中一些元素的浓度随流量的增加而减少,而另外一些似乎与流量之间没有显著的关联。在稳定体系的假设下,所估计的人文活动对痕量元素的贡献可占观测浓度的10％－50％。当与其它河流对比时,发现罗纳河中的颗粒态痕量元素的浓度明显高于那些受人文活动影响较小的体系,而与北美的河流系统接近,表明罗纳河流域的人文活动对河流中颗粒态痕量元素的影响是显著的。 相似文献
19.
为了解三亚近岸海域沉积物地球化学特征,测定了331个站位的表层沉积物23种微量元素含量;利用多元统计法进行相关性及R型因子分析,探讨研究区元素的来源、分布特征及其控制因素。微量元素含量测定结果表明,Sr、Ba、Zr、Rb元素平均值比其他元素高;Be、Cr、Co、Ni、Cu、Zn、Cd、Sb、Pb、U、Zr、Ba、Sc、V、Ga等15种元素含量与海南岛水系沉积物、表层土壤、深层土壤接近,推测沉积物主要来自海南岛。各元素在研究区的空间分布比较复杂,在中部和东部,以Li为代表的15种微量元素随离岸距离增加含量增大;Cd、Sb、Zr、Ba、Rb、Sr、As、Hg的分布特征与其他微量元素相比差异明显。Li等15种元素来源与分布主要受陆源黏土矿物吸附作用控制,Sr主要受海洋生源沉积作用的控制,Zr主要受重矿物的控制,Ba和Rb主要受研究区地质背景控制,而Cd和As的来源与分布则与人类活动有关。 相似文献
20.
南黄海NT2孔沉积地球化学及其物源 总被引：1，自引：0，他引：1
对苏北岸外南黄海陆架区NT2孔岩心进行了地球化学分析和物源判别。南黄海NT2孔化学成分分布表现出一定的分层性,常微量元素组成的垂向变化可自上而下分为5层,常微量元素的R-型聚类分析表明初步可分成5个聚类,R-型因子分析反映常微量元素主要受4个因子控制。研究发现南黄海NT2孔沉积物物源主要为长江和黄河,NT2孔上部0～5·50和5·50～19·40m沉积物以长江源为主,19·40～27m沉积物以黄河源为主,底部54·60m以下沉积物以长江源为主,其间夹近28m厚的沉积物则以长江源为主。结果表明黄河在中更新世中晚期已开始对南黄海陆架沉积作用有明显的影响,长江从晚更新世早期到现代一直对南黄海陆架起着主要作用。 相似文献