淮北煤田煤的稀土元素地球化学

采用仪器中子活化分析法（ＩＮＡＡ）测试了淮北煤田６、３煤层１个煤样的稀土元素含量,并探讨了稀土元素地球化学特征,得出以下认识：１１个样吕的平均ΣＲＥＥ为８１．９５３５ｕｇ／ｇ;稀土元素分布模式呈左高右低的、具Ｅｕ负异常的“Ｖ”型曲线。相关分析、聚类分析的结果表明：稀土元素与灰分、陆源碎屑的元素（Ｓｉ、Ａｌ、Ｔｉ、Ｃｒ、Ｃｏ、Ｎｉ、Ｔｈ、Ｔａ、Ｓｃ和Ｒｂ等）的关系密切,而与海相元素（Ｃａ、Ｓｒ等）关     

马坑铁矿床稀土元素地球化学研究

引言七十年代以来,许多研究者对马坑铁矿进行过深入的研究。关于该矿床的形成机制,特别是含矿建造中一套中一基性岩石和矿体底板岩石的成因,以及矿石的形成方式等问题,曾引起研究者们的特别关注,并开展了热烈讨论。笔者曾对该矿床的地质一地球化学特征进行了较为详细的研究,并指出它是与石炭纪海底火山活动有关的喷气-热液沉积矿床,成矿流体来源于地热对流海水与玄武岩的反应。本文是上述研究的继续和深入,目的在于为     

Geochemistry of dissolved rare earth elements in the Equatorial Pacific Ocean

Seawater samples were collected from four locations in the Equatorial Pacific Ocean during the MR02-K06 cruise of the R/V Mirai and analyzed for dissolved rare earth elements (REEs) using inductively coupled plasma mass spectrometry. According to variations of REE concentrations and Yb/La ratios, the results show that the river input of the Papua New Guinea islands may affect the compositions of REEs in the Equatorial Pacific surface water. The Yb/La values and the REE concentrations in the waters deeper than 3,000 m in the western South Pacific and the Equatorial Pacific Oceans, which represent the characteristics of Antarctic Bottom Water (AABW), demonstrate similar variation trend with depth. This result also indicates that the REEs which originated from the South Pacific Ocean have entered the North Pacific Ocean across the equator with AABW intrusion.     

陈家山矿煤中微量元素和稀土元素地球化学特征

通过对陈家山煤矿中下侏罗统延安组4^#主采煤层中微量元素和稀土元素的测试分析,发现煤中富集亲花岗岩的钨钼族元素W、Mo、Bi、Sn、Ba、Sr和Li,说明该区煤系形成期间的陆源碎屑主要来自花岗岩和花岗片麻岩等中、酸性岩石。4^#煤中ΣREE平均值为98.2×10^-6,稀土元素分布模式十分相似,呈左高右低的宽缓“V”型曲线,Eu负异常明显,反映出稀土元素与陆源碎屑岩关系密切,成煤期间稀土元素来源一致,陆源物质的供应相对稳定。     

Geochemistry of rare earth elements in micro-and macronodules from the pacific bioproductive zone

Concentrations and compositions of rare earth elements (REE) in three micronodule fractions (50–250, 250–500, and >500 μm), coexisting macronodules, and host sediments are examined. The samples were collected from three sites (Guatemala Basin, Peru Basin, and northern equatorial Pacific) located in elevated bioproductivity zones of the surficial water. The influence of micronodule size is dominant for REE compositions and subordinate for REE concentrations. For example, the Ce concentration inversely correlates with the micronodule fraction dimension and drops to the lowest value in macronodules and host sediments. The Ce decrease is generally accompanied by the Mn/Fe increase in micro- and macronodules. Hence, the role of diagenetic source of material directly correlates with the micronodule dimension. The contribution of diagenetic source is maximal for macronodules. The REE signature distinctions of micronodules and macronodules can be attributed to variations of hydrogenic iron oxyhydroxides and diagenetic (hydrothermal) iron hydroxophosphates that are the major REE carriers in ferromanganese ore deposits. The relationship and general trend in the chemistry of coexisting macronodules suggest that they can represent products of the initial stage of nodule formation.     

Geochemistry of rare earth elements in the mainstream of the Yangtze River,China

Water, suspended matter, and sediment samples were taken from 8 locations along the Yangtze River in 1992. The concentration and speciation (exchangeable, bound to carbonates, bound to Fe–Mn oxides, bound to organic matter, and residual forms) of rare earth elements (La, Ce, Nd, Sm, Eu, Tb, Yb, and Lu) were determined by instrumental neutron activation analysis (INAA).The contents of the soluble fraction of REEs in the river are low, and REEs mainly reside in particulate form. In the particles, the chondrite-normalized distribution patterns show significant LREE enrichment and Eu-depletion. While normalized to shales, both sediments and suspended matter samples show relative LREE enrichment and HREE depletion. REEs are relatively enriched in fine-grained fractions of the sediments.The speciation characteristics of REEs in the sediments and suspended matter are very similar. The amount of the five forms follows the order: residual>>bound to organic matter∼bound to Fe–Mn oxides>bound to carbonates>>exchangeable. About 65 to 85% of REEs in the particles exist in the residual form, and the exchangeable form is very low. High proportions of residual REEs reveal that REEs in sediments and suspended matter are controlled by their abundances in the earth's crust. Carbonate, Fe–Mn oxide and organic fractions of REEs in sediments account for 2.4–6.9%, 5.2–11.1%, and 7.3–14.0% of the total contents respectively. They are similar to those in the suspended matter. This shows that carbonates, Fe–Mn oxides and organic matter play important roles during the particle-water interaction processes. By normalization to shales, the 3 forms of REEs follow convex shapes according to atomic number with middle REE (Sm, Eu, and Tb) enrichment, while light REE and heavy REE are depleted.     

四川稀土精矿的稀土元素和微量元素地球化学特征及开发利用意义

产自广东省梅州市玉水铜矿的景文矿,属于含水、重稀土-矾-铝硅酸盐矿物(简写为HREE-V-铝硅酸盐矿物),其化学结构式为Y₂Al₂V₂⁴⁺(SiO₄)₂O₄(OH)₄,该矿物在全球属首次发现,暂未开展相关研究。相对于含轻稀土矿物,含重稀土矿物在电子探针分析过程中,当被高压电子束轰击时,被激发出来的特征X射线线系繁多,线系之间分布更加密集,彼此之间相互重叠的现象也更为严重,要获得理想数据的难度很大,是亟待解决和突破的技术难题。本文对该矿物进行了精细的电子探针定量分析,获得理想的化学成分数据,为新矿物命名提供了理论数据技术支撑。通过对实验方法的探索和总结获得以下结果：①利用15kV加速电压、100nA束流对试样进行全元素扫描,以此确定出17种元素;②在定量分析过程中,对重叠峰进行了剥离;③利用仪器软件中的Zoom-Peak ID程序,选择出17种元素的分析线系、精确的峰位及上下背景值;④选取合适的标样及测试时间等定量分析条件,最终获得理想的定量分析结果(平均总量97.41wt%)。上述四条也是确保获得理想定量分析数据的关键因素。

     

Geochemistry of rare earth elements in bottom sediments of the Brazil Basin, Atlantic Ocean

The sedimentation and ore formation were studied in sediments from nine stations located in the 24°W profile in the Brazil Basin of the Atlantic Ocean. The sediments are represented by mio- and hemipelagic muds, which are variably enriched in hydrothermal iron and manganese oxyhydroxides. As compared to the sediments from other basins of the Atlantic Ocean, these rocks are marked by extremely high manganese contents (up to 1.33%) and maximal enrichment in Ce. It was shown that the positive Ce anomaly is related to the REE accumulation on iron oxyhydroxides. Influence of hydrothermal source leads to the decrease of Ce anomaly and LREE/HREE ratio. In the reduced sediments, preservation of positive Ce anomaly and/or its disappearance was observed after iron and manganese reduction. The REE contents were determined for the first time in the Ethmodiscus oozes of the Brazil Basin. Ore deposits of the Brazil Basin are represented by ferromanganese crust and ferromanganese nodules. Judging from the contents of iron, manganese, rare, and trace elements, these formations are ascribed to the sedimentation (hydrogenic) deposits. They are characterized by a notable positive Ce anomaly in the REE pattern. The extremely high Ce content (up to 96% of total REE) was discovered for the first time in the buried nodules (Mn/Fe = 0.88).     

白银厂铜多金属矿田微量元素和稀土元素地球化学研究

与日本黑矿及现代海底火山岩为主岩矿床相比，白银厂矿田各类矿石，尤其是块状Ｚｎ－Ｐｂ－Ｃｕ矿石具有最高的Ａｓ和Ｂｉ含量，比较高的Ｇａ、Ｃｄ和Ａｕ含量，以及较高的Ａｕ／Ａｇ和Ｃｏ／Ｎｉ比值。该矿田矿石的Ａｕ含量与闪锌矿中铁含量呈负相关关系。小铁山矿床闪锌矿与日本黑矿的闪锌矿微量元素特征很相似。矿田各类矿石ＲＥＥ型式与细碧角斑岩类岩石基体相似，这说明矿石与岩石的物质来源基本一致。研究和对比表明，火山成因     

晋北中高硫煤中稀土元素的地球化学特征

应用中子活化分析方法，测定了晋北两层中高硫煤中稀土元素的含量。通过对稀土元素的分布模式，相关分析和聚类分析的研究，得出如下认识；成煤环境对稀土元素的含量具有控制作用。但中高硫煤中稀土元素总量会受到沉积期后酸性溶液下渗淋滤作用的影响；同一煤层中各分层的稀土元素应具有基本相同的分布模式，异常的稀土元素分布模式指示了沉积期后地质作用的影响；煤中稀土元素的主要赋存状态为无机相，主要来源为陆源碎屑矿物；煤中与稀土伴生的有害元素有V，P，Mo,Cr,Cu,Mo,Th和Cd等，在加工洗选过程中有洁净潜势。     

Geochemistry of the rare earth elements in ferromanganese nodules from DOMES Site A,northern equatorial Pacific

The distribution of rare earth elements (REE) in ferromanganese nodules from DOMES Site A has been determined by instrumental neutron activation methods. The concentrations of the REE vary markedly. Low concentrations characterize samples from a depression (the valley), in which Quaternary sediments are thin or absent; high concentrations are found in samples from the surrounding abyssal hills (the highlands) where the Quaternary sediment section is relatively thick. Moreover, the valley nodules are strongly depleted in the light trivalent REE (LREE) and Ce compared with nodules from the highlands, some of the former showing negative Ce anomalies.The REE abundances in the nodules are strongly influenced by the REE abundances in coexisting bottom water. Some controls on the REE chemistry of bottom waters include: a) the more effective removal of the LREE relative to the HREE from seawater because of the greater degree of complexation of the latter elements with seawater ligands, b) the very efficient oxidative scavenging of Ce on particle surfaces in seawater, and c) the strong depletion of both Ce and the LREE in, or a larger benthic flux of the HREE into, the Antarctic Bottom Water (AABW) which flows through the valley. The distinctive REE chemistry of valley nodules is a function of their growth from geochemically evolved AABW. In contrast, the REE chemistry of highland nodules indicates growth from a local, less evolved seawater source.     

State of rare earth elements in the rare earth deposits of Northwest Guizhou,China

We studied the states of rare earth elements in ore of the Xianglushan rare earth deposit. Rare earth ore samples were tested and examined by scanning electron microscope, electron probe, and chemical leaching. No independent rare earth minerals were detected by scanning electron microscope. Elements detected by the electronic probe for the in situ micro-zone of the sample included: O, Al, Si, Ca, Mg, Fe, Ti, K, Na, S, Cl, C, Cu, Cr, V, and Pt. Rare earth elements were not detected by electron probe. (NH4)₂SO₄, (NH₄)Cl, NaCl, and H₂SO₄ were used as reagents in chemical leaching experiments that easily leached out rare earth elements under the action of 10% reagent, indicating that the rare earth elements in ore are mainly in the ionic state rather than present as rare earth minerals.     

重庆龙潭组煤中稀土元素地球化学及地质成因分析

运用电感耦合等离子体质谱(ICP MS)、X射线荧光光谱(XRF)、X射线衍射(XRD)等方法对重庆龙潭组煤中稀土元素的地球化学特征进行研究。结果表明,各煤样稀土元素分布模式相似,总体呈左高右低的宽缓的“V”型曲线,轻稀土曲线段“右倾”,重稀土曲线段较为“平坦”,成煤沼泽受陆源碎屑影响较大。南桐5#煤稀土元素含量高,接近全国平均值的2倍,受汉南古陆、大巴山古陆和龙门山岛屿控制,少量陆源碎屑物来自康滇古陆。东林6#煤中的稀土元素含量低于全国平均值水平,海水作用明显,煤样中稀土元素含量未受碱性火山灰的影响,但其底板受碱性火山灰影响强烈。根据煤层稀土元素含量及其比值分析,研究区龙潭组为海湾/潟湖潮坪及浅海碳酸盐沉积的沉积环境。     

Geochemistry of the Rare Earth Elements in Natural Terrestrial Waters：A Review of What Is Currently Knows

The range of observed chemical compositions of natural terrestrial waters varies greatly especially when compared to the essentially constant global composition of the oceans.The concentrations of the REEs in natural terrestrial waters also exhibit more variation than what was reported in seawater,In terrestrial waters ,pH values span the range from acid up to alkaline,In addition,terrestrial waters can range from very dilute waters through to highly concentrated brines.The REE concentrations and their behavior in natural terrestrial waters reflect these compositional ranges,Chemical weathering of rocks represents the source of the REEs to natural terrestrial waters and ,consequently,the REE signature of rocks can impart their REE signature to associated waters,In addition,Because of the typical low solubilities of the REEs both surface and solution complexation can be important in fractionating REEs in aqueous solution.Both of these processes are important in all natural terrestrial waters,however,their relative importance varies as a function of the overall solution composition,In alkaline waters,for example,Solution complexation of the REEs with carbonate ions appears to control their aqueous distributions whereas in acid waters,the REE signature of the labile fraction of the REEs is readily leached from the rocks.In circumneutral pH waters,both processes appear to be important and their relative significance has not yet been determined.     

Geochemistry and biogeochemistry of rare earth elements in a surface environment (soil and plant) in South China

Plants and soils derived from different kinds of parent materials in South China were collected for analyses of rare earth elements (REEs) by inductively coupled plasma-mass spectrometry (ICP-MS). The distribution patterns and transportation characteristics of REEs in the soil–plant system were studied. The results show that geochemical characteristics of REEs depend on the types of soils, soils derived from granite being the highest in REE concentration. In a soil profile, REE concentrations are higher in B and C horizons than those in A horizon, with Eu negative anomaly and Ce positive anomaly. Plants of different genera growing in the same sampling site have quite similar REE distribution pattern, but plants of the same genera growing in different soils show considerable variation in characteristics of REEs. The patterns of the different parts of plant resemble each other, but the slope of the patterns becomes different. REEs have fractionated when they were transported and migrated from soil to plant root, stem and leaf, revealing that heavy REEs are relatively less available. REEs distributions in plants are influenced by the soil they grow in and also characterized by their individual biogeochemical characteristics. Biological absorption coefficients indicate difference of REE absorption capacity of plants. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Geochemistry of rare earth elements in the modern sediments of Amur Bay (the Japan/East Sea)

The distribution of REE in the bottom sediments of Amur Bay accumulated over the last 100 years was studied, and the REE contents were evaluated. The REE contents normalized to North American Shale Composite (NASC) show a negative Ce anomaly and a predominance of LREE and MREE. The inflow and accumulation of REE in the bottom sediments are influenced mainly by natural sources, whereas their dependence on anthropogenic factors is minimal.     

Stabilisation of divalent rare earth elements in natural fluorite

Summary ?The occurrence of divalent rare earth elements (Sm²⁺, Yb²⁺, Tm²⁺, and Ho²⁺) in natural fluorite is evaluated using a suite of 37 samples deriving mainly from Sn–W deposits in the Erzgebirge (Germany), Central Kazakhstan, and the Mongolian Altai. Trace element composition was determined by ICP-AES and ICP-MS. The defect structure of the samples was studied by cathodoluminescence (CL), electron paramagnetic resonance (EPR), and optical absorption spectroscopy. Reduction of cubic Sm³⁺, Yb³⁺, Tm³⁺, and Ho³⁺ under radioactive irradiation produces the corresponding divalent centres. Our data suggest a preferable formation of Sm²⁺ and Yb²⁺ under thorium and of Tm²⁺ and Ho²⁺ under uranium irradiation. Irradiation (indicated by intense brownish (thorium) and deep purple (uranium) coloration of fluorite) gives rise to a population of divalent centres in equilibrium with their decay. However, sporadic radioactive irradiation and stabilisation of the divalent state of the REE by other electron defects were found in most cases. Three models of stabilisation of Sm²⁺, Yb²⁺, Tm²⁺, and Ho²⁺ are discussed. The most effective mechanism for Sm, Yb, Tm, and Ho is coupling with Fe³⁺ centres (REE³⁺+Fe²⁺ → REE²⁺+Fe³⁺). Accordingly, the occurrence of Fe³⁺ centres in natural fluorite is regarded to indicate not an oxidising, but rather a reducing environment during fluorite precipitation. Originally incorporated in the divalent form, Fe²⁺ was converted to Fe³⁺ by radioactive irradiation. Such a conclusion is in agreement with the finding of high contents of interstitial fluorine providing tetragonal local compensation of trivalent REE centres in crystals with high Fe³⁺. If Fe is not present, compensation of divalent Sm, Yb, and Tm is achieved by radiogenic oxidation of Ce(Pr, Tb)³⁺ accompanied by charge transfer (REE³⁺+Ce(Pr, Tb)³⁺ → REE²⁺+ Ce(Pr, Tb)⁴⁺). Ho²⁺ is sometimes stabilised by a hole trapped by an electron localised on a F vacancy (Ho³⁺+e⁻ on □_F → REE²⁺+ self-trapped exciton). Because Sm²⁺ is optically active, the stabilisation by Fe³⁺ (stable up to temperatures above 350 °C) or Ce(Pr, Tb)⁴⁺ (unstable even under visible light) in samples may be determined by careful observations in the field. Institut für Geotechnik, ETH Zürich, ETH-H?nggerberg, Zürich, Switzerland Stanford Linear Accelerator Center, Menlo Park, CA, USA Received January 8, 2002; revised version accepted June 10, 2002     

深海稀土分布规律与成矿作用

深海稀土是近年发现的一种富集中-重稀土的新型海洋矿产资源,其资源量远超陆地稀土储量,具有重要的潜在应用价值。中国是继日本之后在国际上第二个开展深海稀土调查研究的国家,2011年以来,先后在中印度洋海盆、东南太平洋和西太平洋深海盆地发现了大面积富稀土沉积区,在全球大洋中初步划分出4个深海稀土成矿带：西太平洋深海稀土成矿带、中—东太平洋深海稀土成矿带、东南太平洋深海稀土成矿带和中印度洋海盆-沃顿海盆深海稀土成矿带。深海富稀土沉积主要发育在深海盆地的沸石粘土和远洋粘土中,属于自生成因;部分发育在洋中脊附近的盆地中,受到热液作用的影响。研究发现,深海粘土中稀土元素主要赋存于生物磷灰石中,海水是稀土元素的主要来源;在早期成岩阶段,稀土元素在深海沉积物中发生转移和重新分配,并最终富集于生物磷灰石中;大水深（CCD面之下）、低沉积速率和强底流活动是深海稀土大规模成矿的主要控制因素。今后需要继续加大深海稀土基础调查,加强深海稀土调查探测技术研发,并开展海陆稀土成矿作用对比研究,揭示深海稀土成矿机制和规律。     

西昌普诗地区中—下白垩统小坝组岩石–紫色土剖面稀土元素地球化学特征分析

探究山地–丘陵区稀土元素地球化学特征,对了解区域生态地质环境具有十分重要的意义。本文在大凉山区生态地质调查的基础上,选取西昌市普诗地区中–下白垩统小坝组4个典型土壤垂向剖面进行系统采样分析,揭示了西昌普诗地区岩石–土壤剖面中14种稀土元素（La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu）的地球化学分布、迁移及富集特征。结果表明：相似的环境下不同类型成土母岩形成的同类土壤中稀土元素含量有所不同,泥岩–紫色土剖面（PM0909）、砂岩–紫色土剖面（PM03-3）、粉砂质泥岩–紫色土剖面（PM04-4）、泥质粉砂岩–紫色土剖面（PM0924）等代表性剖面土壤中,稀土元素含量依次为126.870 mg/kg、116.472 mg/kg、163.926 mg/kg、175.231 mg/kg,各个剖面稀土元素含量差异与成土母岩的岩性和粘土矿物含量关系密切,黏土矿物对稀土元素具有一定的吸附作用;研究区4个剖面呈现明显的“V”字形右倾模式,负Eu异常明显,重稀土部分较为平坦,属于轻稀土富集型,这与成土过程中稀土元素（REEs）淋溶及其成土母岩化学性质差异有关;不同成土母岩形成的剖面迁移系数存在一定的差异,迁移系数高值主要分布在各个剖面的淀积层（B层）底部及母质层（C层）,这是由于REEs受到淋溶、淀积作用和黏土矿物吸附、解吸作用的共同结果。本次研究结果可以为大凉山区大尺度的生态地质研究提供一定的理论支持和科学依据。