磷酸盐化作用对富钴结壳元素相关性的影响

为了探讨磷酸盐化作用对富钴结壳元素相关性的影响,用电感耦合等离子体发射光谱法(ICP-AES)和重量法测试了中太平洋CX海山富钴结壳的主、微量元素及稀土元素.首先以P质量分数和Y异常把富钴结壳分为磷酸盐化型[w(P)＞0.57%且具有正Y异常]和未磷酸盐化型[w(P)＜0.57且具有负Y异常].结果表明,相比于未磷酸盐化型结壳,磷酸盐化型结壳中某些元素出现相对亏损和富集,其中亏损元素的亏损顺序为Si＞Al＞Fe＞Co＞Li＞K＞Pb＞Na＞Mg＞V,而富集元素的富集顺序为P＞Ca＞REE＞Ba＞Sc＞Mo＞Cu＞Ni＞Ti＞Sr＞Zn＞Mn;两类结壳相同元素问的相关性既有共性也有差别,Si-Al、Si-Fe和Si-Ca 等元素间的相关性在两类结壳中变化不大,而P-Mn,P-Fe,Mn-Fe,Fe-Co等元素间的相关性则发生重要改变,这些相关性发生变化的元素对可指示结壳是否遭受磷酸盐化作用,元素丰度以及元素相关性的变化与磷酸盐化作用引起的结壳矿物组成变化有关.     

中太平洋多金属结壳的地球化学特征

采用XRF和ICP AES法对中太平洋CA等6座海山的4 0多个站位的多金属结壳中化学元素进行测试与分析, 并结合其他资料对调查区结壳主要成矿元素的含量组成、特征变化、元素间的相关关系以及结壳与水深、地形等重要环境因子进行探讨.研究表明太平洋海山结壳中元素丰度特征具有多种变化类型, 中太平洋结壳主成分和成矿元素丰度明显高于马绍尔群岛, 而与西北太平洋、麦哲伦海山相近; 中太平洋结壳化学元素相关关系分析表明: Ca与P、Al与K呈显著正相关性; Mn与Al呈显著负相关性.研究还发现中太平洋结壳富Co(0.6 3%)而贫Cu(0.1 1 %)及高Fe(1 6.9%)低Mn(2 1.3%)的分布特征, 与深海多金属结核在含量分布特征上存在较大差异.与多金属结核相比: 结壳中Mn组元素含量显著降低, Fe组元素含量和稀土总量明显增大, 尤其是Co和REEs的变化最为突出。      

大洋磷酸盐化作用对富钴结壳元素富集的影响

中国首次对与大洋富钴结壳密切相关的磷酸盐化作用进行了研究。对取自西太平洋麦哲伦海山区一厚度为 10cm的富钴结壳样品 ,自顶至底以 5mm间距采取了 2 0个分层样品进行了成矿元素和稀土元素分析。结果表明 ,未被磷酸盐化的新结壳和磷酸盐化的老结壳间主要成矿元素的含量相差显著。老结壳中Fe、Mn、Si、Al、Zn、Mg、Co、Ni、Cu元素亏损 ,亏损次序为Co >Ni>Mg >Al>Mn >Si>Cu >Zn >Fe;而Ca、P、Sr、Ba、Pb元素含量增加 ,富集次序为P >Ca >Ba >Pb >Sr。研究认为 ,结壳中磷酸盐化作用的强弱制约着富钴结壳成矿元素含量的变化 ,磷酸盐化作用是造成老结壳中主要成矿元素Co、Ni等贫化流失的根本原因。研究还表明 ,磷酸盐化作用对富钴结壳的稀土元素丰度也产生一定影响 ,使老结壳的稀土总量和Ce含量高于新结壳 ,但未显著改变其稀土配分模式和分馏特征。研究证实 ,老结壳的Y正异常与磷酸盐化作用无关。磷酸盐化作用的研究为富钴结壳矿产资源的评价和综合利用提供了有用信息。     

铁岭市东部山区野生经济植物榛子营养元素地球化学特征

对辽宁省铁岭市东部山区野生经济植物榛子样品中的常量营养元素P、K、Ca、Na、Mg、S,14种营养微量元素和稀土元素含量进行了分析.结果表明,本区的榛子样品其主量元素化学特征属K > P > Ca型,其中Na元素含量变异系数最大,为44.27.微量元素含量水平均在植物元素含量正常值变化范围内,由高到低,元素含量排列顺序为;Mn > Si > Fe > Zn > B > Cu > Ni > F > Cr > Mo > Co > Se > I > V.其中,V元素变异系数最大,为93.18.稀土元素总量∑REE（平均值）为29.66×10^-9,属低含量.元素相关性分析表明,元素K与Na、Mg,S与Mg、Ca,P与K、Na、Mg、Ca,Fe与Mn,Co与Mn,Cu与Zn之间,在0.01水平都表现出极显著的正相关,反映这些元素之间的吸收积累有很好的协同作用.     

太平洋富钴结壳中碲元素的地球化学特征及其富集机制探讨

文章通过对采自太平洋海域不同海山上68个结壳样品中Te元素地球化学特征的研究,探讨了富钴结壳中控制Te元素富集的古海洋氧化还原环境及其富集机制。分析表明,太平洋海域中大多数结壳的w(Te)变化于13.4×10-6~115.8×10-6,平均50×10-6,是海水w(Te)的109倍;结壳中w(Te)与Mn/Fe比值呈正相关,相关系数为0.51;与Fe呈负相关,相关系数为-0.61,显示结壳中Te与Co有类似的地球化学特征。古海水氧化还原环境的改变是控制结壳中Te元素含量变化的重要因素;能反映古海水氧化还原环境的Ce异常与结壳中Te含量基本呈同步变化趋势,Te含量具有随古海水氧化程度减弱而降低的特征。结壳中Te元素的富集主要受控于其内的Mn/Fe比值。Te元素的富集机制除被海水中带微弱正电荷的FeOOH胶体以库伦静电吸附外,还可能与δ-MnO2表面上以一种表面络合物方式的富集机制有关。Te进入结壳的存在形式及其在不同古海洋环境中的富集机制还有待进一步研究和探讨。     

麦哲伦海山群MK海山富钴结壳稀土元素的赋存相态

利用ICP-OES和ICP-MS,分析了麦哲伦海山群西北端MK海山2 170 m水深的MKD23B-3号富钴结壳样品,获得了其剖面上主元素、稀土元素（REE）和Y含量数据,并基于元素含量间的线性相关关系,研究了REE和Y的赋存相态。结果显示:该样品剖面从基岩到表面可划分为5层,第Ⅰ、Ⅱ层为磷酸盐化壳层,第Ⅲ、Ⅳ、Ⅴ层为未磷酸盐化壳层。在未磷酸盐化壳层中,REE和Y主要赋存在δ-MnO₂相中;而在磷酸盐化壳层中,REE和Y除了赋存在Fe、Mn氧化物相中外,主要赋存在独立于碳氟磷灰石（CFA）的矿物相态中,可能为稀土的磷酸盐。并提出利用磷酸盐中REE/Y 估算富钴结壳磷酸盐化壳层次生稀土的方法,据此估算了MK海山富钴结壳磷酸盐化壳层次生稀土的量。在该样品中,次生稀土占稀土总量的42%~88%,近一半以上的稀土是次生的,磷酸盐化作用对于REE和Y的次生富集具有显著的贡献;因此解读磷酸盐化富钴结壳的稀土元素（特别是Nd同位素）古海洋记录必须排除次生稀土元素的干扰。     

中太平洋YJC海山富钴结壳矿物组成与元素地球化学

运用等离子光谱、等离子质谱、X射线衍射、红外光谱和场发射电镜等分析测试方法,对太平洋威克(Wake)海岭YJC海山中的富钴结壳中不同构造层的矿物组成和元素地球化学研究表明:矿石矿物是水羟锰矿和少量的钙锰矿,脉石矿物是磷灰石、石英和方解石等,微量矿物有蒙脱石、高岭石、钠沸石、斜发沸石、伊利石、水黑云母、磁铁矿和角闪石等。老结壳磷灰石的质量分数>10%,P>1%;新结壳磷灰石<10%,P<1%。老结壳相对富集Cu、Ca、P等元素,新结壳相对富集TMn、TFe、Co、Ni、Ba、Zn、Pb、Mo等元素。结壳内部纹层构造的不同位置及包体内的微区成分变化较大,TMn和TFe呈同消长关系,但TMn/TFe值相对稳定。结壳的稀土元素总量为1761.88×10-6,Ce具明显的正异常。老结壳相对富集稀土元素,新结壳略富Eu。     

中太平洋YJA海山富钴结壳矿物组成与元素地球化学

研究样品采自马尔库斯（MARCUS）海脊YJA海山。利用等离子光谱、等离子质谱、X-射线衍射、红外光谱、场发射电镜等分析测试方法,对富钴结壳中不同构造层的矿物组成和元素地球化学进行了研究。该结壳为一大型板状新结壳,矿石矿物是水羟锰矿,脉石矿物是石英、斜长石、磷灰石等,微量矿物有蒙脱石、高岭石、钠沸石、水黑云母、片沸石等。从结壳的底部构造层到顶部构造层,TMn,Ni,Cu, Ba,Zn等元素的质量分数逐渐减少,TFe逐渐增加,Co变化不大;在相对疏松的构造层中,Si,Al,K,Na,Ca,Mg,Ti,P,Li,Rb等元素相对富集;结壳的稀土元素总量是1 982.27×10^-6,Ce具明显的正异常。不同构造层稀土元素的演化趋势是：Ce与Mn等元素相同,其他稀土元素（Y除外）与Fe等相似。     

富钴铁锰结壳的控矿要素和成矿过程:以西太平洋为例

富钴铁锰结壳(简称富钴结壳)是产出在海山、岛屿斜坡及海底高地上的一种潜在新型矿产资源,由铁锰氧化物和氢氧化物组成,富含Co、Ni、Zn、Pb、Ce、Pt、REE等金属元素,其中Co的平均含量较陆地原生钴矿高几十倍.     

太平洋富钴结壳中碲元素的地球化学特征及其富集机制探讨

文章通过对采自太平洋海域不同海山上68个结壳样品中Te元素地球化学特征的研究,探讨了富钴结壳中控制Te元素富集的古海洋氧化还原环境及其富集机制。分析表明,太平洋海域中大多数结壳的w（Te）变化于13.4×10^-6~115.8×10^-6,平均50×10^-6,是海水w（Te）的10⁹倍;结壳中w（Te）与Mn/Fe比值呈正相关,相关系数为0.51;与Fe呈负相关,相关系数为-0.61,显示结壳中Te与Co有类似的地球化学特征。古海水氧化还原环境的改变是控制结壳中Te元素含量变化的重要因素;能反映古海水氧化还原环境的Ce异常与结壳中Te含量基本呈同步变化趋势,Te含量具有随古海水氧化程度减弱而降低的特征。结壳中Te元素的富集主要受控于其内的Mn/Fe比值。Te元素的富集机制除被海水中带微弱正电荷的FeOOH胶体以库伦静电吸附外,还可能与δ-MnO₂表面上以一种表面络合物方式的富集机制有关。Te进入结壳的存在形式及其在不同古海洋环境中的富集机制还有待进一步研究和探讨。     

Classification of and elemental fractionation among ureilites

Concentrations of Ni, Zn, Ga, Ge, Cd, In, Ir and Au in five ureilites can be combined with petrographie evidence to yield a well-defined suite extending from Goalpara (heavily shocked, low Ir concentration, low Ir/Ni ratio) through Haverö, Dyalpur, Novo-Urei to Kenna (moderately shocked, high Ir concentration, high Ir/Ni ratio). Arguments are presented indicating that this suite represents the sampling of a vertical section within the ureilitic parent body. The large range in Ir/Ni and Ir/Au ratios indicates greater efficiency of extraction of primitive, refractory metal in the Goalpara region than in the Kenna region, and implies that higher maximum temperatures prevailed in the former during the production of ureilitic ultramafic silicates by a partial melting process.

A major impact event injected a deposit of C-rich material into the ultramafic silicates. This C-rich material had a moderately high content of metal; there is no direct evidence that it contained volatiles other than the rare gases. High Ca contents of the ferromagnesian minerals indicate that the ultramafics were hot at the time the injection occurred; the zoning of these mineral grains also indicates high temperatures (ca. 1400 K) and low pressures (S 10atm) such that reaction between C and Fe₂SiO₄ could occur, but that cooling occurred too quickly to allow complete equilibration. The ureilitic C-rich material appears to represent an important type of primitive material.

Two siderophile-rich components are necessary to explain the relative siderophile trends in ureilites. We interpret the high-Ir component to be a refractory nebular condensate or residue that was retained during the partial melting event. The low-Ir component, which roughly resembles E4 chondrite siderophiles, is attributed to metal injected together with the vein material.     

The elemental composition of plankton

Phytoplankton samples, collected in Monterey Bay, California, were analyzed for their Pb, Hg, Cd, Co, Ag, Cr, Ti, V, Mn, Ni, Cu, Fe, Zn, AI, Mo, Ba, Sr, K, Ca, Mg, Na and SiO₂ content. The results of these analyses were categorized on a chemical basis and the sample data were placed in three groups: Group I, Ti not detected; Group II, Ti detected; and Group III, Sr concentrators present. Levels of most elements were higher in Groups II and III for a variety of reasons that are discussed in the text. The siliceous frustules, remaining after organic-matter digestion, were also analyzed for the elements listed above. Significant amounts of Al, Ti, Fe, Mn, Cu and Zn were found.Zooplankton and microplankton samples, collected in Monterey Bay, California; off the coast of Oregon; and on a transect between Hawaii and Monterey, were also analyzed for the elements listed above (except Si). In general, element levels in the inshore and offshore zoo-plankton were similar; however, the microplankton samples, in which strontium was highly concentrated, were almost always higher in Pb, Hg, Cu, Fe and Zn.     

ODP 1144站钻孔沉积物中微玻璃陨石的元素地球化学特征

利用电子探针和激光探针等离子体质谱方法分析了取自南海北部的ODP1144钻孔沉积物中的微玻璃陨石和取自邻近的广东省湛江和吴川玻璃陨石的主元素和微量元素组成。结果显示，这些微玻璃陨石属于亚洲-澳大利亚散落区的普通微玻璃陨石。从成分上看，这些微玻璃陨石存在两种不同的类型，其中的绝大部分Al2O3含量在19.0%以上，属于高Al类型，相应的难熔微量元素含量也比较高；个别微玻璃陨石Al2O3含量（13.0%)和难熔微量元素含量较低，微量元素含量和特征比值都与邻近的广东省湛江和吴川的玻璃陨石相近。元素地球化学特征意味着，这些微玻璃陨石来源于同一靶源区，但靶区的物质组成并不均一。     

The elemental composition of suspended particles from the Yellow and Yangtze Rivers

The elemental composition of suspended particles from the Yellow River is similar to those of the loess terraces and the world's average soils. The contents of Zn, Cu, Ni, Co and Pb in the suspended particles are higher in the Yangtze River than in the Yellow River, indicating pollution inputs or the high-side of natural variability.     

Lithium elemental and isotopic variations in rock-melt interaction

Despite the occurrence of highly variable lithium (Li) elemental distribution and isotopic fractionation in mantle mineral, the mechanism of Li heterogeneity and fractionation remains a controversial issue. We measured Li contents and isotopic compositions of olivine and clinopyroxene xenocrysts and phenocrysts from kamafugite host lavas, as well as minerals in melt pockets occurring as metasomatic products in peridotite xenoliths from the Western Qinling, central China. The olivine xenocrysts in the kamafugites show compositional zonation. The cores have high Mg# (100 × Mg/(Mg+Fe); 91.0–92.2) and Li abundances (5.63–21.7 ppm), low CaO contents (≤0.12 wt%) and low δ⁷Li values (−39.6 to −6.76‰), which overlap with the compositional ranges of the olivines in the melt pockets as well as those in peridotite xenoliths. The rims of the olivine xenocrysts display relatively low Mg# (85.9–88.2), high CaO contents (0.19–0.38 wt%) and high δ⁷Li values (18.3–26.9‰), which are comparable to the olivine phenocrysts (Mg#: 86.4–87.1; CaO: 0.20–0.28 wt%; Li: 12.4–36.8 ppm; δ⁷Li: 18.1–26.0‰) and the silicate-melt metasomatized olivines. The clinopyroxene phenocrysts and clinopyroxenes in the melt pockets have no distinct characteristics with respect to the Li abundances and δ⁷Li values, but show higher and lower CaO contents, respectively, than the clinopyroxenes from silicate and carbonatite metasomatized samples. These features indicate that Li concentration and isotopic signatures of the cores of the xenocrysts recorded carbonatite melt-peridotite reaction (carbonatite metasomatism) at mantle depth, and the variations in the rims probably resulted from xenocryst–host magma interaction during ascent. Our results reveal that the interaction with carbonatite and silicate melts gave rise to an increase in Li abundance in minerals of peridotite xenoliths at mantle depth or during transportation. In terms of δ⁷Li, the carbonatite and silicate melts produced remarkably contrasting δ⁷Li variations in olivine. Based on the systematic variations of Li abundances and Li isotopes in olivines, we suggest that the δ⁷Li value of olivine is a more important indicator than that of clinopyroxene in discriminating carbonatite and silicate melt interaction agents with peridotites.     

Re-Os elemental and isotopic systematics in crude oils

Analysis of 12 worldwide oil samples show that Re and Os abundances are positively correlated with the asphaltene content of oil. Light oils with <1% asphaltene content have basically no measurable Re or Os. Within oil, Re and Os are present dominantly in the asphaltene fraction (>83%), with <14% Re and Os found in the maltene fraction, this distribution is similar to other trace metals such as V and Mo. Rhenium and Os could be present in oil as metalloporphyrin complexes, but given their abundance in the asphaltene component they are also likely bound by heteroatomic ligands. The ¹⁸⁷Re/¹⁸⁸Os and ¹⁸⁷Os/¹⁸⁸Os values in asphaltene calculated at the estimated time of oil generation (Os_i) are similar to those of the whole oil, as expected from the elemental results. This suggests that the asphaltene fraction can be used to approximate the Re-Os isotopic compositions of the whole oil. Os isotopic compositions in oils show a considerable range, from ¹⁸⁷Os/¹⁸⁸Os of 1.9-6.0, and they correlate positively with the age of the proposed source rock. Re/Os ratios also show a large range and overlap the Re/Os ratios found in typical oil source rocks such as organic rich shale.     

The chemistry of lava-seawater interactions II: the elemental signature

The flow of lava into the ocean at the shoreline of Kilauea Volcano during the ongoing Pu’u O’o eruption has allowed a detailed study of the geochemical interaction between lava and seawater. This paper focuses on the chemistry of the major and minor elements in the fluids that resulted from this interaction. The elemental enrichments in these fluids are dominated by three processes: (1) evaporation of water from seawater, which creates solutions enriched in the major elements found in seawater, (2) congruent dissolution of the basalt glass matrix, which is limited by the solubility of some of the elements in seawater, and (3) removal of volatile phases from the lava on contact with seawater.Using a simple model of volatile emanation (using published emanation coefficients) and congruent dissolution, we are able to explain the concentrations observed for the majority of elements in precipitation from the steam plume at the shoreline lava entry and in water allowed to interact with molten lava in controlled experiments. Fe, Al, Ti, and some of the rare earth elements (REEs) in precipitation samples from the steam plume at the lava entry were > 10,000-times enriched over their ambient seawater concentrations, suggesting that these elements may be useful for identifying submarine eruptions. The flux of elements from the Kilauea ocean lava entry is greater than that from a typical midocean ridge hydrothermal vent field for Al, Cd, Co, and the REEs, whereas the opposite is true for the remainder of the elements studied.     

Comparison of elemental composition of recent and ancient carbonaceous sediments

The concentrations of 13 macroelements and 36 microelements are determined in calcareous deposits from recent basins, namely, the Black Sea (coccolith and sapropel oozes), the Namibian shelf (diatomaceous oozes), and the Peruvian shelf (diatomaceous-terrigenous oozes). The essential similarity of the composition of the microelements is established for all three types of sediments, including calcareous, terrigenous, and siliceous sediments. The comparison of these data with the average composition of the world shales reveals similar trends of microelement distribution, which supports the former hypothesis about the comparable environment of formation of both ancient and some modern basins.     

苏鲁榴辉岩中磷灰石的矿物学和微量元素地球化学

磷灰石是榴辉岩中最常见的副矿物之一,见证了高压-超高压变质岩从原岩形成、俯冲和折返所伴随的物理化学过程。为进一步揭示苏鲁超高压榴辉岩经历的物理和化学过程,我们对取自中国大陆科学钻探工程（CCSD）主孔岩心和苏北地表露头榴辉岩中的磷灰石进行了详细的岩相学分析和LA-ICP-MS原位微量元素分析。分析结果表明,在苏鲁榴辉岩中,磷灰石绝大多数是在超高压变质作用阶段重结晶生长的。未受退变质影响的磷灰石富含LREE和Sr元素,退变质作用促使磷灰石中活动性较强的LREE和Sr明显降低而HREE含量略微升高,并产生负Eu异常。磷灰石边部HREE的升高可能与折返过程中的升温作用和石榴子石分解有关,Eu负异常的产生可能还与退变质过程中发生了氧逸度f^O2的降低有关;结合前人对磷灰石中“出溶”现象的研究,提出榴辉岩磷灰石中的独居石“出溶体”很可能是磷灰石与富含NaCl和硅酸盐的退变质流体发生交代反应所致,磷灰石中硫化物“出溶体”的形成除了氧逸度降低的原因外,可能也与折返过程中发生的短期升温作用有关。超高压变质岩从进变质-峰期→早期退变质→角闪岩相退变质阶段,变质流体可能经历了氧化→还原→氧化状态的复杂变化。