基于独立成分分析的马里亚纳弧后地幔源区特征研究

对采自太平洋洋中脊(277组)、印度洋洋中脊(159组)、马里亚纳海槽(53组)、马里亚纳岛弧(39组)、中南劳海盆(72组)共600组玄武岩数据进行了独立成分分析,从Sr-Nd-Pb五维同位素比值空间提取出占样本方差99%的3个独立成分(IC1,IC2,IC3),并利用这3个独立成分(ICs)与微量元素比值之间的相关性来讨论独立成分的起源。分析结果表明:IC1可以将马里亚纳海槽玄武岩与太平洋洋中脊及马里亚纳岛弧玄武岩区分,并且IC1值与(La/Sm)N比值呈正相关。IC2可以将马里亚纳海槽和马里亚纳岛弧玄武岩区分,而且IC2值与Ba/Th比值呈正相关;IC3可以将弧后盆地和洋中脊玄武岩区分,同时IC3值与Th/Nb呈负相关。分析独立成分的统计特征和微量元素比值特征可知,IC1与印度洋型MORB地幔的富集组分相关,IC2与太平洋板块俯冲产生的含水流体相关,IC3与再循环俯冲沉积物熔体相关。根据ICs地理分布特点,我们认为:1)马里亚纳海槽北部比南部受到更多印度洋型MORB地幔富集组分的影响,表明印度洋型MORB地幔可能从北部置换太平洋型MORB地幔;2)海槽北部地幔源区则是受到再循环沉积物熔体的影响较大,而中部和南部地幔源区可能受到更多俯冲流体的影响。     

Buried nodules and associated sediments from the central Indian basin

Buried nodules from siliceous sediments in the central Indian Basin are morphologically variable and mineralogically consist ofd-MnO₂ and incipient todorokite. Compositionally they are weakly diagenetic. The sediment coarse fractions (>63 μm) at different depths show variable abundances of micronodules, volcanic glass shards and biodebris. Dissolution of biodebris increases and abundance of micronodules decreases with increasing depth. Enrichment in Mn, Fe, Cu, Ni, Co, together with a decrease in organic carbon in the sediment column, may result from diagenetic metal remobilization. Diagenetically remobilized trace metals might have been utilized for the growth of micronodules over the buried nodules. The details of the chemical analyses of buried nodules and associated sediments can be obtained from the first author.     

Variation of sediment geotechnical properties between the greater antilles outer ridge and the nares abyssal plain

Abstract

It is clear from morphology alone that distinctly different dynamic and sedimentary processes can be expected to be associated with the Greater Antilles Outer Ridge relative to those of the adjacent Nares Abyssal Plain. This difference is further substantiated by seismic reflection data which show the ridge to be a very large prism of acoustically transparent sediment in contrast to the stratified deposits of the abyssal plain. An examination of the geotechnical properties of the near‐surface (0 to 2.4m) deposits of the two areas also reveals distinct differences in their sedimentological characteristics. The outer ridge sediments, of more or less homogenous clay‐size material, display much higher water contents, porosities, sensitivities, plasticity, and organic carbon contents in contrast to the abyssal plain deposits which are much less homogenous owing to the presence of turbidite sequences. The turbidites themselves are uniquely contrasted to the other abyssal plain sediments by their higher silt content, wet bulk density, shear strength, and sensitivity.     

山东半岛东部海域表层沉积物元素组成及物源指示意义

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。     

东马努斯盆地高镁安山岩物质来源及演化过程——基于全岩主微量和同位素分析

对东马努斯盆地高镁安山岩做了全岩主微量和Sr-Nd-Pb同位素分析,并结合前人测试数据,探究了岩浆物质来源及演化过程。由主量元素[MgO、CaO、FeOT(全铁)、Al_2O_3、TiO_2和P_2O_5]含量随着硅含量的升高而降低和La/Sm随着La含量的升高而保持不变可知,岩浆在演化过程中只发生了矿物的分离结晶,分离的矿物可能为橄榄石、辉石、斜长石、钛铁矿和磷灰石。东马努斯盆地高镁安山岩的Pb和大离子亲石元素(K,Rb,Sr,Ba和U)的富集、高场强元素(Nb,Th,Ta和Ti)的亏损说明岩浆受到了俯冲板块脱水作用的影响。推测该区高镁安山岩是流体交代的地幔楔部分熔融形成的。由Sr-Nd同位素混合模拟结果可知东马努斯盆地高镁安山岩主要来源于马努斯MORB(洋中脊玄武岩),少量来自于太平洋蚀变洋壳和海底沉积物。根据Sr-Nd-Pb同位素特征推测岩浆混合作用发生在地幔源区,属于源区混染,岩浆在喷发的过程中没有发生同化混染作用,也没有加入其他体系的物质。     

Characteristics of manganese micronodules as indicators of sedimentation conditions in pelagic sediments

Pelagic sediments from three cores in the northern tropical Pacific zone (the northeast basin) have been analyzed for particle size and composition, as well as for number, mass and the distribution of protosyngenetic authigenic manganese micronodules (MN) in them. The sequences are represented by Quaternary carbonate-free clayey–radiolarian, radiolarian–clayey oozes, miopelagic clays, sometimes enriched in radiolarians, pre-Pleistocene miopelagic and eupelagic clays, zeolite–clayey sediments, and zeolitites. Based on factual data (volume of wet sediment, weight of dry sediment and micronodules, their number and proportions of four fractions, the contribution of MN in sediment, and others), the values of different parameters were calculated. The obtained parameters are statistically similar, which allowed us to reveal background and anomalous horizons of sediments and to assume their sedimentation conditions. Similar values of Р_MN/N_MN, Р_fr > 0.05 mm, Р_MN/Р_sed and the mass of micronodules suggest that precisely these parameters reflect the main variations in conditions of pelagic sedimentation.     

西南印度洋中脊表层沉积物中存在热液组分的地球化学证据

Hydrothermal materials in deep-sea sediments provide a robust tracer to the localized hydrothermal activity at mid-ocean ridges. Major, trace and rare earth element(REE) data for surface sediments collected from the ultraslow spreading Southwest Indian Ridge are presented to examine the existence of hydrothermal component.Biogenic carbonate oozes dominate all the sediment samples, with CaO content varying from 85.5% to 89.9% on a volatile-free basis. The leaching residue of bulk sediments by ~5% HCl is compositionally comparable to the Upper Continental Crust(UCC) in SiO_2, Al_2O_3, CaO, MgO, alkali elements(Rb, Cs) and high field strength elements(Nb, Ta, Zr, Hf, Ti). These detritus-hosted elements are inferred to be prominently derived from the Australian continent by means of eolian dust, while the contribution of local volcaniclastics is insignificant. In addition, the residual fraction shows a clear enrichment in Fe, Mn, and Ba compared with the UCC. Combining the positive Eu anomaly of residual fraction which is opposed to the UCC but the characteristic of hydrothermal fluids and associated precipitates occurred at mid-ocean ridges, the incorporation of localized hydrothermal component can be constrained. REE mixing calculations indicate that more than half REE within the residual fraction(~55%–60%) are derived from a hydrothermal component, which is inferred to be resulted from a diffuse fluid mineralization. The low-temperature diffuse flow may be widely distributed along the slow-ultraslow spreading ridges where crustal faults and fissures abound, and probably have a great mineralization potential.     

Geochemical variation in ferromanganese nodules and associated sediments from the Pacific Ocean

The major and minor element compositions of a suite of abyssal sea-floor ferromanganese nodules and associated sediments from the eastern central Pacific have been used to examine inter-element relationships and the mineralogy of the nodules, the relationship between the composition of nodules and their associated sediments and regional variations in composition with respect to likely modes of formation of such deposits. Apart from Mn and Fe, significant proportions of the total Ti, Ca, Mg, K, Ba, Sr, Th and Y and almost all the P, As, Ce, Co, Cu, Mo, Ni, Pb, Zn and Zr are present in the oxide fractions of the nodules. The Mg, Ba, Cu, Mo, Ni and Zn contents are significantly correlated with the Mn content, while Ti, P, As, Pb, Sr, Y and Zr are similarly correlated with the total Fe content.Nodules from the northeastern tropical Pacific have Mn/Fe ratios higher than those in the oxide fractions of their associated sediments, todorokite as the principal Mn phase and relatively high concentrations of minor elements associated with Mn. Nodules from the south central Pacific have Mn/Fe ratios similar to those in the oxide fractions of the associated sediments, δ-MnO₂ as the only Mn-phase, and relatively high concentrations of minor elements associated with Fe. There appears to be a smooth gradation in composition in the tropical Pacific between these two end members.The regional compositional variation is interpreted as a reflection of different sources of metals for, and different growth mechanisms of, sea-floor nodules. The oxide precipitate from sea water consists of δ-MnO₂, has a relatively low Mn/Fe ratio and minor element contents related to the total Fe and Mn(δ-MnO₂) content. The oxide precipitate forming in areas of very low sedimentation as a result of diagenetic remobilisation in the surface sediment consists of todorokite, and has a high Mn/Fe ratio and enhanced metal content in the Mn-(todorokite)phase. Available information on the morphology and compositional variation of individual nodules from the tropical Pacific corroborates these contrasting metal sources and suggests that they can be resolved on the scale of an individual oxide concretion.     

A near-bottom survey of lineated abyssal hills in the equatorial pacific

A 250 km² area of abyssal hills in the vicinity of 14°N, 126°W (between the Clarion and Clipperton Fracture Zones in the Equatorial Pacific) was surveyed in detail using an instrument package towed close to the deep sea floor, the MPL Deep Tow device. Both topography and near bottom magnetic field are lineated perpendicular to the major fracture zones. Except for a few localized depressions, the sediment surface is generally smooth and of low relief with maximum elevation differences of 200 m and slopes of six degrees. Several small graben-like troughs and depressions were observed, most of them near the crest of one abyssal hill. The largest trough is two kilometers long, 250 m wide and 50 m deep with steep sides (>30°). These troughs are tentatively interpreted as the result of tensional separation at the tops of the hills caused by down-slope creep and consolidation of the pelagic sediments.Contribution of the Scripps Institution of Oceanography, new series.     

冲绳海槽中段沉积物物源识别及其热液活动指示

冲绳海槽中段热液活动区表层沉积物的主、微量和稀土元素分析结果表明:区内沉积物主要由陆源物质与热液源物质组分组成,Hg、Au、Sb、Cu、Pb、Zn、Ba、As、Fe和Co等微量元素富集;沉积物的化学风化程度中等,A-CN-K图解表明其暂未受到钾交代影响,且其母岩成分接近花岗闪长岩;北美页岩标准化稀土配分模式曲线整体较为平坦,轻重稀土分馏较弱,部分样品具有与热液流体类似的明显正铕异常.受热液活动影响,部分沉积物中的Fe、Cu、As、Pb和Zn显著富集,结合样品所处站位,整体显示含金属沉积物-过渡沉积物-正常沉积物的空间分配模式.结合(La/Sm)N、(La/Yb)N比值指示区内沉积物的陆源物质主要来自于黄河与台湾岛河流.     

The response of abyssal organisms to low pH conditions during a series of CO2-release experiments simulating deep-sea carbon sequestration

The effects of low-pH, high-pCO₂ conditions on deep-sea organisms were examined during four deep-sea CO₂ release experiments simulating deep-ocean C sequestration by the direct injection of CO₂ into the deep sea. We examined the survival of common deep-sea, benthic organisms (microbes; macrofauna, dominated by Polychaeta, Nematoda, Crustacea, Mollusca; megafauna, Echinodermata, Mollusca, Pisces) exposed to low-pH waters emanating as a dissolution plume from pools of liquid carbon dioxide released on the seabed during four abyssal CO₂-release experiments. Microbial abundance in deep-sea sediments was unchanged in one experiment, but increased under environmental hypercapnia during another, where the microbial assemblage may have benefited indirectly from the negative impact of low-pH conditions on other taxa. Lower abyssal metazoans exhibited low survival rates near CO₂ pools. No urchins or holothurians survived during 30–42 days of exposure to episodic, but severe environmental hypercapnia during one experiment (E1; pH reduced by as much as ca. 1.4 units). These large pH reductions also caused 75% mortality for the deep-sea amphipod, Haploops lodo, near CO₂ pools. Survival under smaller pH reductions (ΔpH<0.4 units) in other experiments (E2, E3, E5) was higher for all taxa, including echinoderms. Gastropods, cephalopods, and fish were more tolerant than most other taxa. The gastropod Retimohnia sp. and octopus Benthoctopus sp. survived exposure to pH reductions that episodically reached −0.3 pH units. Ninety percent of abyssal zoarcids (Pachycara bulbiceps) survived exposure to pH changes reaching ca. −0.3 pH units during 30–42 day-long experiments.     

Agglutinated abyssal foraminifers of the equatorial pacific

The quantitative study of the distribution and taxonomic composition of recent living and dead (without plasma) benthic foraminifers revealed three foraminiferal assemblages in the bottom sediments of the Pacific Ocean at depths of 3350 to 4981 m. The assemblage dominated by the epibenthic Lagenammina difflugiformis, Reophax dentaliniformis, and Saccorhiza ramosa occupies the slopes of underwater hills. The assemblage with a high share of the infaunal Cribrostomoides subglobosum, C. nitidum, and Ammobaculites agglutinans is registered on the abyssal plateau. The assemblage with a significant proportion of the large Astrorhiza and Reophax species, which are characterized by an active way of life, populates gentle slopes and narrow depressions with potentially strong bottom currents.     

Stoichiometry among bioactive trace metals in the Chukchi and Beaufort Seas

The distribution of Al, Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb in seawater was investigated in the Chukchi and Beaufort Seas of the western Arctic Ocean in September 2000. The unfiltered and filtered seawater samples were used for determination of total dissolvable metal (TDM) and dissolved metal (DM), respectively. The concentration of labile particulate metal (LPM) was estimated with the difference between that of TDM and DM. The concentrations of TDAl, TDMn, TDFe, TDCo and TDPb varied substantially in the study area. The high concentrations occurred at stations near the Bering Strait, in the Mackenzie delta, and above reductive sediments on the shelf and slope. These elements were mostly dominated by labile particulate species, such as Fe?CMn oxides and species adsorbed on terrestrial clay. DCo was correlated with DMn over the study area (r?=?0.78, n?=?135), and the slope of the regression line was 27 times higher at a pelagic station than at a shelf station. TDNi, TDCu, TDZn and TDCd showed relatively small variations and were generally dominated by dissolved species. There was a moderate correlation between DCd and phosphate for all samples (r?=?0.79), whereas there were no significant correlation between the other DMs and nutrients. TDNi and TDCu showed a remarkable linearity for most stations except those near the Bering Strait (R ²?=?0.95, n?=?126). These results suggest that biogeochemical cycling including uptake by phytoplankton and remineralization from settling particles has only minor control over the distribution of trace metals in this area. Using the present data, the annual input of bioactive trace metals form the Bering Strait and the Mackenzie River was estimated. Also, the trace metal compositions of major water masses were evaluated. The dissolved elemental ratio was P:Al:Mn:Fe:Co:Ni:Cu:Zn:Cd?=?1:1.2?×?10^?2:4.4?×?10^?4:1.4?×?10^?3:3.7?×?10^?5:3.7?×?10^?3:1.4?×?10^?3:4.5?×?10^?3:2.2?×?10^?4 for Canada Basin deep water (CBDW). This ratio was significantly different from that for Pacific deep water and Bering Sea water, suggesting substantial modification of the trace metal compositions of seawater in the study area.     

Trace metals in the Western Pacific: temporal and spatial variability in the concentrations of Cd, Cu, Mn and Ni

Profiles of total dissolvable Cd, Cu, Mn and Ni are reported for samples collected from the southwest Pacific in 1989, from the western equatorial Pacific along 155°E at 5°S, 0° and 5°N in 1990 and 1993, and along the equator from 143°E to 152°E and in the Bismarck Sea in 1997 and 2000. Profiles of Cd along 155°E in 1990 and along the equator were essentially the same but, in 1993, Cd values at 5°N were higher by a factor of about 1.5–2 than at 5°S over the depth range 500–1500 m. Similar, but less pronounced, differences were observed for PO₄ and Ni. Cd and Ni were both strongly correlated with PO₄, and an even stronger correlation was found between Ni and Cd. The concentration of Ni did not fall below ≈2 nmolkg⁻¹, even in the nitrate-depleted waters of the western equatorial Pacific, where primary production is strongly dependent on recycled nitrogen (mainly ammonia and urea). It is proposed that this residual Ni is not bioavailable and that Ni could be biolimiting, since the metabolism of urea requires the nickel-containing enzyme urease. The impact of the Sepik River on Cd, Cu and Ni concentrations was small but elevated concentrations of Mn were observed near the Sepik River and close to the coast suggesting that the rivers and sediments on the north coast of New Guinea are a significant local source of Mn to the Bismarck Sea. Simple mass balance calculations show that the elevated levels of Mn observed in the Equatorial Undercurrent cannot be due to input from the rivers of New Guinea and they were attributed to the trapping of particulate matter due to strong current shear. A strong hydrothermal source of Mn was observed in the central Bismarck Sea.     

Trends of trace metal (Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb) distributions at the oxic-anoxic interface and in sulfidic water of the Drammensfjord

Anoxic sulfidic waters provide important media for studying the effect of reducing conditions on the cycling of trace metals. In 1987–1988, dissolved and particulate trace metal (Mn, Fe, Co, Ni, Cu, Zn, Cd and Pb) concentrations were determined in the water column of the anoxic Drammensfjord basins, southeastern Norway. The iminodiacetic acid type chelating resin (Chelex 100) was used for the preconcentration of trace metals. The trace metal concentrations were determined using atomic absorption spectrophotometry (AAS), differential pulse polarography (DPP), and differential pulse-anodic stripping voltammetry (DP-ASV).It was observed that the trace metals Mn and Fe were actively involved in the processes of redox cycling (oxidationreduction and precipitation-dissolution) at the O₂/H₂S interface. The dissolved concentrations of Mn, Fe and Co showed maxima just below the O₂/H₂S interface. The seasonal enhancement in the maxima of both dissolved and particulate Mn and Fe at the redox cline is mainly governed by the downward movement of water which carries oxygen. An association of Co with the Mn cycle was observed, while the total dissolved Ni was decreased by only 10–35% in the anoxic waters. The dissolved concentrations of Cu, Zn, Pb and, to a lesser extent, Cd decreased in the anoxic zone.     

Preliminary study on the distribution of nutrients, organic matter, trace metals in sea surface microlayer in Xiamen Bay and Jiulong Estuary

-The enrichment of nutrients (NOa-, NOa-, PO43-), suspended particles, organic matter (POC, PON,DOC) , and trace metals (Cu, Ni, Cd) was determined in the sea surface microlayer of Xiamen Bay and Jiulong Estuary. The mean enrichment factors ([Xi]microlayer/[Xi ]15cm in depth) mostly ranged between 1 . 0 and 2. 0. The dissolved forms were the major forms of the components measured, the enrichment of dissolved organic matter and suspended particles could lead to the changes in the total amount and speciation of nutrients and trace metals. No correlation was observed between sample concentrations, speciation, enrichment factors and sample locations. However, some evidence shows that these parameters are correlated with sea state, indicating the complexity and dynamic nature of the sea surface microlayer.     

‘Live’ benthic foraminifera at an abyssal site in the equatorial Pacific nodule province: Abundance,diversity and taxonomic composition

Replicate sediment samples were obtained from 3 closely spaced stations in the Kaplan East (KE) area of the abyssal eastern Equatorial Pacific (∼15°N, 119°W; ∼4100 m water depth), just below the carbonate compensation depth. At each site, 2 (Stns 827, 838) or 3 (Stn 824) complete cores (57 mm i.d.) were subsampled using 2–3 cut-off syringes of 6.6 cm³ cross-sectional area. The 0–1 cm sediment layers (>32 μm fraction) of these 20 subsamples together yielded 12,513 small, rose-Bengal stained benthic foraminifera dominated by agglutinated taxa, most of them morphologically simple monothalamous types or komokiaceans. Almost two-thirds (65%) of specimens were either obvious fragments, mainly of komokiaceans and tubular foraminifera, or single chambers or small groups of chambers believed to be fragments of very fragile komokiaceans. The remaining 4438 specimens (35%) were considered to be complete individuals. Most (78%) of these complete tests were indeterminate agglutinated spheres (termed ‘psammosphaerids’) that constituted 27.6% of all specimens (complete plus fragments). Complete individuals that could be assigned to either described or undescribed species accounted for 983 specimens (22% of complete tests=7.6% of all specimens); only 26 specimens (0.59% of complete individuals) were calcareous and these had invariably lost their tests through dissolution. Some groups exhibited considerable spatial heterogeneity. For example, 45% of the 3455 indeterminate psammosphaerids and 45% of the 3087 Komokiacean-like chambers occurred in single subcores. A total of 252 morphospecies was recognised; 168 were represented by complete individuals and 84 by fragments. There are clear differences between these Pacific assemblages and those from other oceans; in particular, psammosphaerids and isolated komokiacean chambers appear to be much more prevalent in the Pacific compared to the Atlantic Ocean. Some morphospecies present in Kaplan samples are known from the Atlantic but many are not. Such species may either (1) be ubiquitous but undersampled because they are rare or (2) have geographically patterned distributions. Without further sampling, there is no way to distinguish between these 2 possibilities. Fossilisable tests represent a very small component of the KE assemblage. Many of the delicate, monothalamous species that have little fossilisation potential, including the komokiaceans, accumulate stercomata (waste pellets) and may consume organic material and bacteria associated with sediment. Because of their enormous abundance at abyssal depths, these poorly known taxa probably play a substantial role in carbon cycling over vast areas of the Pacific seafloor.     

Simplified synthesis of an 8-hydroxyquinoline chelating resin and a study of trace metal profiles from Jellyfish Lake, Palau

We report a simplified synthesis, and some performance characteristics, for 8-hydroxyquinoline (8-HOQ) covalently bonded to a chemically resistant TosoHaas TSK vinyl polymer resin. The resin was used to concentrate trace metals from stored, acidified seawater samples collected from Jellyfish Lake, an anoxic marine lake in the Palau Islands. The Mn, Fe, and Zn profiles determined from the 8-HOQ resin extraction were similar to those determined using Chelex-100 resin. The Zn and Cd profiles did not exhibit removal by sulfide “stripping” in contrast to other anoxic marine basins. The profiles of Co and Ni also exhibited elevated concentrations in the anoxic hypolimnion. The solution speciation and saturation states for the metals were calculated using revised metal-bisulfide stability constants. The calculations suggest that the MS(HS)⁻ species dominates the solution speciation for Mn, Co, Ni, Zn, Cd, and Pb. Cu(I) is modeled as the CuS⁻ or Cu(HS)₂⁻ species, while Fe(II) behaves as the free Fe²⁺ cation. The Mn, Co, Ni, Cu and Cd concentrations appeared to be at least 10-fold undersaturated, while the Fe(II), Zn, and Pb concentrations were close to saturation with respect to their metal sulfides.     

海洋沉积物孔隙水中痕量金属元素的测试分析方法

孔隙水是沉积物-海水界面链接沉积物颗粒和上覆水体的一个重要过渡相态,针对其研究可更好地了解痕量金属在固-液界面的早期成岩过程。近年来,针对孔隙水中痕量元素研究的方法较为匮乏,为此建立了一种分析测定海洋沉积物孔隙水中7种痕量金属元素(Mn、Cu、Zn、Ni、Cd、Co、Pb)的方法,该方法使用Nobias PA1树脂进行富集分离,再使用电感耦合等离子体质谱(ICP-MS)进行测试,可针对孔隙水中的痕量金属元素进行准确分析。通过实验结果发现该方法最优实验条件为: Nobias PA1树脂富集时的pH值为5.5~6.0,洗脱酸浓度为1.3 mol/L硝酸,体积为1 mL。同时,样品需进行紫外消解4 h以上以分解有机络合物,该消解步骤对Cu和Co这两种元素尤其重要。该方法通过加标回收获得Mn、Cu、Ni、Co和Pb的回收率在92%~100%, Zn和Cd的回收率分别为72%和82%; Mn、Cu、Zn、Ni的方法检出限范围为0.03~0.53 nmol/L, Cd、Co、Pb的方法检出限范围为2.66×10^-3~8.60×10^-3 nmol/L,满足孔隙水中痕量金属浓度的测试需求。同时,根据检出限计算的结果显示,孔隙水样品只需1 mL,即可应用该方法进行测试。应用该方法测试了一根采集于北黄海中部沉积物短柱的孔隙水样品,测试结果显示其垂相分布合理、较符合早期成岩过程规律。此研究为分析海洋沉积物孔隙水中痕量金属元素提供了一种准确而简便的方法。     

The distribution of zinc,nickel, manganese,cadmium, copper,and iron in some surface waters from the world ocean

Determinations of Zn, Ni, Mn, Cd, Cu, and Fe have been carried out on 51 near-shore and 38 open-ocean surface seawaters from various regions of the World Ocean.The concentrations of the trace metals have been established in the open-ocean waters, and have been used as “baselines” to evaluate trace-metal enhancement in near-shore regions. The factors by which the trace metals are enriched in near-shore regions vary from one element to another and, according to the highest concentration factors found, decrease in the order Zn = Mn > Cd = Cu = Ni.These elements exhibit differences in their distributions between near-shore and open-ocean waters, and they have been divided into two types on this basis: Type I, in which the largest number of samples in both shelf and open-ocean waters lie in the same concentration range. Zinc, cadmium, and copper are Type I elements. Type 2, in which the largest number of samples of near-shore waters lie in a higher concentration range than the largest number of samples of open-ocean waters. Nickel and manganese are Type 2 elements.The concentrations of Mn, Cd and Zn are similar in open-ocean surface waters from the South Atlantic and Indian Ocean, but Cu and Ni have higher concentrations in the former ocean.There is considerable variation in the concentrations of the trace metals in near-shore surface waters from various regions of the World Ocean. These variations are discussed in detail.