Rare Earth Element and Trace Element Features of Gold-bearing Pyrite in the Jinshan Gold Deposit,Jiangxi Province

Jinshan gold deposit is located in northeastern Jiangxi,South China,which is related to the ductile shear zone.It has a gold reserve of more than 200 tons,with 80%of gold occurring in pyrite. The LREE of gold-bearing pyrite is as higher as 171.664 ppm on average,with relatively higher light rare earth elements（LREE;159.556 ppm） and lower HREE（12.108 ppm）.TheΣLREE/ΣHREE ratio is 12.612 and（La/Yb）_N is 11.765.These indicate that pyrite is rich in LREE.The（La/Sm）_N ratio is 3.758 and that of（Gd/Yb）_N is 1.695.These are obvious LREE fractionations.The rare earth element（REE） distribution patterns show obvious Eu anomaly with averageδEu values of 0.664,andδCe anomalies of 1.044.REE characteristics are similar to those of wall rocks（regional metamorphic rocks）,but different from those of the Dexing granodiorite porphyry and Damaoshan biotite granite.These features indicate that the ore-forming materials in the Jinshan gold deposit derived from the wall rocks, and the ore-forming fluids derived from metamorphic water.The Co/Ni ratio（average value 0.38） of pyrite suggests that the Jinshan gold deposit formed under a medium-low temperature.It is inferred from the values of high-field strength elements,LREE,Hf/Sm,Nb/La,and Th/La of the pyrite that the ore-forming fluids of the Jinshan gold deposit derived from metamorphic water with Cl〉F.

Association between Exposure of Rare Earth Elements and Outcomes of In Vitro Fertilization-Embryo Transfer in Beijing

Objective The study aimed to investigate the impact of rare earth elements(REEs)exposure on pregnancy outcomes of in vitro fertilization-embryo transfer(IVF-ET)by analyzing samples from spouses.Methods A total of 141 couples were included.Blood and follicular fluid from the wives and semen plasma from the husbands,were analyzed for REEs using inductively coupled plasma mass spectrometry(ICP-MS).Spearman's correlation coefficients and the Mann–Whitney U test were used to assess correlations and compare REE concentrations among three types of samples,respectively.Logistic models were utilized to estimate the individual REE effect on IVF-ET outcomes,while BKMR and WQS models explored the mixture of REE interaction effects on IVF-ET outcomes.Results Higher La concentration in semen(median 0.089 ng/mL,P=0.03)was associated with a lower fertilization rate.However,this effect was not observed after artificial selection intervention through intracytoplasmic sperm injection(ICSI)(P=0.27).In semen,the REEs mixture did not exhibit any significant association with clinical pregnancy.Conclusion Our study revealed a potential association between high La exposure in semen and a decline in fertilization rate,but not clinical pregnancy rate.This is the first to report REEs concentrations in follicular fluid with La,Ce,Pr,and Nd found at significantly lower concentrations than in serum,suggesting that these four REEs may not accumulate in the female reproductive system.However,at the current exposure levels,mixed REEs exposure did not exhibit reproductive toxicity.

Rare earth elemental and Sr isotopic evidence for seawater intrusion event of the Songliao Basin 91 million years ago

Petrogenesis of lacustrine dolostone is closely related with paleo-lake water conditions.Here we report the high spatial-resolution petrographic and geochemical results of a lacustrine dolomite nodule from the Qingshankou Formation,the Songliao Basin.Sedimentary and elemental signatures confirm the protogenetic origin of this nodule and its effectiveness in recording geochemical characteristics of paleo-lake water during dolomitization.The low Y/Ho ratios,middle rare earth element(MREE)enrichment and subtle positive Eu anomalies within the nodule indicate a fresh water source.However,the Sr isotope values in the core of the nodule(0.7076-0.7080)are close to contemporaneous seawater(0.7074),yet different from the modern river(0.7120)and the host black shale(0.7100).On the premise of excluding the influence of hydrothermal fluids,the significantly low strontium isotope values of the lacustrine dolomite might be caused by seawater interference during dolomitization.Our findings demonstrate that lacustrine dolomite within black shales is not only a faithful tracer of diagenetic water environment,but also a novel and easily identified mineralogical evidence for episodic seawater intrusion event(91 Ma)in the Songliao Basin,which supplements other paleontological and geochemical evidence.

Effects of Rare-earth and Microalloying Elements on the Microstructure Characteristics of Hypereutectoid Rails

We performed thermal simulation experiments of double-pass deformation of hypereutectoid rails with different microalloying elements at a cooling rate of 1℃/s and deformation of 80%to explore the influence of rare-earth and microalloying elements on the structure of hypereutectoid rails and optimize the composition design of hypereutectoid rails.Scanning electron microscopy,transmission electron microscopy,X-ray diffraction,and other characterization techniques were employed to quantitatively analyzed the effects of different microalloying elements,including rare-earth elements,on pearlite lamellar spacing,cementite characteristics,and dislocation density.It was found that the lamellar spacing was reduced by adding various microalloying elements.Cementite lamellar thickness decreased with the refinement of pearlite lamellar spacing while the cementite content per unit volume increased.Local cementite spheroidization,dispersed in the ferrite matrix in granular form and thus playing the role of dispersion strengthening,was observed upon adding cerium(Ce).The contributions of dislocation density to the alloy strength of four steel sheet samples with and without the addition of nickel,Ce,and Ce–copper(Cu)composite were 26,27,32,and 37 MPa,respectively,indicating that the Ce–Cu composite had the highest dislocation strengthening effect.The Ce–Cu composite has played a meaningful role in the cementite characteristics and dislocation strengthening,which provides a theoretical basis for optimizing the composition design of hypereutectoid rails in actual production conditions.

Biomedical rare-earth magnesium alloy:Current status and future prospects

Biomedical magnesium(Mg)alloys have garnered significant attention because of their unique biodegradability,favorable biocompatibility,and suitable mechanical properties.The incorporation of rare earth(RE)elements,with their distinct physical and chemical properties,has greatly contributed to enhancing the mechanical performance,degradation behavior,and biological performance of biomedical Mg alloys.Currently,a series of RE-Mg alloys are being designed and investigated for orthopedic implants and cardiovascular stents,achieving substantial and encouraging research progress.In this work,a comprehensive summary of the state-of-the-art in biomedical RE-Mg alloys is provided.The physiological effects and design standards of RE elements in biomedical Mg alloys are discussed.Particularly,the degradation behavior and mechanical properties,including their underlying action are studied in-depth.Furthermore,the preparation techniques and current application status of RE-Mg alloys are reviewed.Finally,we address the ongoing challenges and propose future prospects to guide the development of high-performance biomedical Mg-RE alloys.

Trace Elements and Rare Earth Elements of Sulfide Minerals in the Tianqiao Pb-Zn Ore Deposit,Guizhou Province,China

Trace elements and rare earth elements（REE） of the sulfide minerals were determined by inductively-coupled plasma mass spectrometry.The results indicate that V,Cu,Sn,Ga,Cd,In,and Se are concentrated in sphalerite,Sb,As,Ge,and Tl are concentrated in galena,and almost all trace elements in pyrite are low.The Ga and Cd contents in the light-yellow sphalerites are higher than that in the brown and the black sphalerites.The contents of Ge,Tl,In,and Se in brown sphalerites are higher than that in light-yellow sphalerites and black sphalerites.It shows that REE concentrations are higher in pyrite than in sphalerite,and galena.In sphalerites,the REE concentration decreases from light-yellow sphalerites,brown sphalerites,to black sphalerites.The ratios of Ga/In are more than 10, and Co/Ni are less than 1 in the studied sphalerites and pyrites,respectively,indicating that the genesis of the Tianqiao Pb-Zn ore deposit might belong to sedimentary-reformed genesis associated with hydrothermal genesis.The relationship between LnGa and LnIn in sphalerite,and between LnBi and LnSb in galena,indicates that the Tianqiao Pb-Zn ore deposit might belong to sedimentary-reformed genesis.Based on the chondrite-normalized REE patterns,δEu is a negative anomaly（0.13-0.88）,andδCe does not show obvious anomaly（0.88-1.31）;all the samples have low total REE concentrations（〈3 ppm） and a wide range of light rare earth element/high rare earth element ratios（1.12-12.35）.These results indicate that the ore-forming fluids occur under a reducing environment.Comparison REE compositions and parameters of sphalerites,galenas,pyrites,ores,altered dolostone rocks,strata carbonates,and the pyrite from Lower Carboniferous Datang Formation showed that the ore-forming fluids might come from polycomponent systems,that is,different chronostratigraphic units could make an important contribution to the ore-forming fluids.Combined with the tectonic setting and previous isotopic geochemistry evidence,we conclude that the ore-deposit genesis is hydrothermal,sedimentary reformed,with multisources characteristics of ore-forming fluids.

Jurassic Black Shales Facies from Qiangtang Basin (Northern Tibet): Rare Earth and Trace Elements for Paleoceanographic Implications

The Biluo Co and Amdo 114 station, northern Tibet, cropping out the Early Toarcian and Middle-Late Tithonian （Jurassic） organic-rich black shales, have been a focus to petroleum geologists in discussing their oil-producing potential. This paper first reports the trace elements and rare earth elements to discuss the paleoenvironments, redox conditions and sedimentary mechanisms of those black shales. Both sections exhibit variation in trace element abundances with concentrations 〈0.1 ppm to 760 ppm, mostly enriched in V, Cr, Ni, Cu, Zn, Mo, Ba and U. Element ratios of Ni/Co, V/Cr, U/Th and V/（V＋Ni） plus U were used to identify redox conditions. The shale-normalized rare earth element （REE） patterns are characterized by the flat-shale type with instable Ce anomalies and very weekly positive Eu anomalies. Positive Ceanom values are significant with values varying between - 0.064 and 0.029 in Biluo Co, which may be interpreted as release of REE and input of riverine terrestrial matter with rich Ce （resulting in pH change） during the anoxic conditions. In the middle parts of Amdo 114 station, distinct negative Ceanom values are observed （-0.238 to -0.111） and associated surface water warming were interpreted as being related to a major sea level rise. In contrast, the formation of the black shales in the lower and upper part of the studied succession took place during a cooler （Ceanom values 〉-0.10）, lower surface water productivity, and lower sea-level stage. Thus, we emphasize the role of different factors that control the formation of local and regional black shales. The most important factors are sea-level fluctuations and increasing productivity.

Rare Earths, Trace Element Characteristics of High-Mg Volcanic Rocks of Yixian Formation in Sihetun West Liaoning Province and Its Apocalypse

The high-Mg volcanic rocks of the Yixian Formation in the Sihetun area have the obvious characteristics of mantie-derived lava in rare earth, trace element characteristics with high Mg # （62 - 70） and high content of compatible elements. In the meantime, the volcanic rocks also have the obvious characteristics of Crust-source material in rare earth, trace element characteristics with high ∑ REE （ 158.78 × 10^-6 - 359.66 × 10^-6 ）, high （La/Yb） N （ 14.61 - 29.60）, high La/Nb（2.37 - 7.52） and high Ba/Nb （67.58- 205.96）, obvious positive anomaly of Pb and negative anomaly of Nb, Ta in trace element spider-gram. In Sr-Nd-Pb isotope the （^87Sr/^86Sr）i ratio is higher than 0.706 and the εNd（ t ） ratio is from - 3.4 to - 13, both reflect enriched Mantle characteristics. The characteristics above of the volcanic rocks combined with the content of Sr, Ba, Y, Yb and the ratio of Sr/Y show that the volcanic rocks have the property of the Sanukite rocks in Setouchi Japan beside subduction zone, and illuminate that the Sanukite rocks can be formed not only in island-arc near subduction zone but also in intro-plate. The analysis indicates that the high-Mg volcanic rocks in the Sihetun area result from the collective function of mantle-derived lava and crust-source materials. The result illuminates that the West Liaoning region is very special in tectonic geochemical background in Cretaceous in East China, and is an ideal region for us to further study the characteristics of magmatic activity as well as the process of Crust-Mantle interaction in Eastern China.

Geochemical Features of Trace and Rare Earth Elements of Pumice in Middle Okinawa Trough and Its Indication of Magmatic Process

Pumice,the most widely distributed volcanic rock in Okinawa Trough,is loose and porous.Since its formation,it has definitely suffered from the denudation of the sea to different degrees.In order to truly reveal the geochemical features of pumice,we choose the method of mineral separation.Firstly,the phenocryst is separated from glass.Then the phenocryst is divided into light and heavy mineral compositions.By ICP-MS(inductively coupled plasma mass spectrometry) analytical technology,the contents of trace and rare earth elements in the whole pumice,the glass and the heavy and light mineral compositions are determined respectively.By researching the elemental geochemical features,the magma dynamic processes are found.It shows that the initial magma for the pumice in Okinawa Trough came from the depleted mantle,from which the N-MORB(normal type of mid-ocean ridge basalt) is formed,homologous with the local basalts.But they are formed in different periods of magma crystal fractionation.Featured with sufficient crystal fractionation for pumice,it is found that the earlier crystallizing minerals are olivine,plagioclase and pyroxene.The pumice magma,formed from the depleted mantle,was mixed with additional subduction-related materials(components),and contaminated with the mass from upper crust when it rose up into the crust.As the Okinawa Trough is a back-arc basin in its early back-arc spreading stage,its magmatism has a series of its own unique characteristics,different from not only the mid-ocean ridge expansion,but also the mature back-arc basin.

Bioleaching of trace elements and rare earth elements from coal fly ash

Coal fly ash originated from coal combustion has high concentrations of metals. If suitable leaching techniques are identified, then coal fly ash could serve as a useful source of valuable minerals including rare earth elements (REEs). In this study, three microbial strains, Candida bombicola, Phanerochaete chrysosporium and Cryptococcus curvatus were tested on their performance of leaching trace elements and REEs from fly ash. Through comparing mineral loss and leaching efficiencies resulting from indirect leaching or use of the culture supernatant, C. bombicola was identified to be the best leading to the highest mineral loss and extracting efficiencies of trace elements and REEs among the three strains. The highest mineral loss observed from using the supernatant of this yeast strain was 59.7%. Among all trace elements, As and Mo had the highest leaching efficiency of 80.9% and 79.5%. respectively. The same leaching test led to 67.7% of Yb and 64.6% of Er dissolved from the ash. This study, thus, demonstrated that bioleaching is feasible for leaching metals out of fly ash. The C. bombicola strain deserves further investigation due to its robust actions on metal leaching.

Trace and Rare Earth Element Geochemistry of Micrite Mound Carbonates and Other Related REE Mineralized Carbonates from Bayan Obo Area in Inner Mongolia

Geochemical study on trace and rare earth element geochemistry was carried out for different carbonates including the very REE-rich ones in the main ore bodies, a carbonatite dyke and two micrite mounds from Heilaobao far away from the Bayan Obo ore deposit, and Xishan in west Beijing. The results show that both carbonatite dyke and REE mineralized carbonates (dolomite and marble) in the main ore bodies and outside ore bodies have similarities to each other, with very extreme positive anomaly of Ba, Th, Nb, La, Ce, Nd, Sm, Pb, medium positive anomaly of Y, Ho, Tb, Er, Yb and negative anomaly of Sc, Ti and Cu. The REE concentration in the mineralized carbonates changes greatly, the total REE content changes from 262×10^(-6) in both east and west ore deposits to 104562 ×10^(-6) (10.46%), which is relatively lower than those samples of carbonatite dyke, whose REE contents vary greatly, from 1% up to 20 % of mass fraction. Light REE in the carbonatites are enriched and highly fractionated relative to heavy REE and there is no Eu anomaly. The REE distribution patterns of both mineralized carbonate and carbonatite dyke are of some similarities. However, the sedimentary carbonate micrite of Salinhudong Group in Heilaobao far outside the ore bodies and the pure carbonates from Xishan in Beijing, central part of North China plate, have the similarities in REE distributions with much lower REE contents, which are significantly different from those of carbonatite dyke and REE mineralized carbonate. In Bayan Obo district, both carbonates in the ore deposit and micrite mound outside the ore deposit underwent widespread metasomatism by fluids that resulted in formation of the superlager Fe-Nb-REE mineralization. It appears that the carbonates represent the evolution products of different geological stages.

Simultaneous Determination of Trace Rare Earth Elements and Other Elements in High Purity Terbium Oxide (Tb_4O_7) by ICP-AES After HPLC Separation Using P507 Resin

This article describes a new method for the simultaneous determination of trace rare earth elements (REEs) and non rare earth elements (NREEs) in high purity terbium oxide by ICP-AES after HPLC separation using P507 resin. The chromatographic separation of the analytes from the matrix using dilute nitric acid as mobile phase was studied. The experimental results showed that a favorable separation of trace metals (Cu and Gd) from the matrix (Tb) can easily be achieved by elution with dilute nitric acid within 25 min. The proposed method was applied to the determination of trace metals (Ca, Cu, Mg, Mn, Ni, Si, La, Ce, Pr, Nd, Sm, Eu and Gd) in high purity terbium oxide. The detection limits (DLs) for the analytes ranged from 0.4-4.0 μg\5g -1, and the recoveries are from 78%-105%.

Multi-Trace Element and Rare Earth Element Composition of Coastal Casuarina Equisetifolia Ecosystem in Hainan Island,China

46 trace elements including 14 rare earth elements (REEs) in coastal Casuarina equisetifolia plant-soil system from 9 sampling sites in Hainan Island were detected by using ICP-MS. The aim is to explore the biogeochemical characteristics of migration and translocation of trace elements in soil-plant system and their function on the changes of environmental geochemistry. The results indicate that multi-trace elements in coastal sandy soil in Hainan Island are at very low level. The multi-element patterns are quite similar among plant,sandy soil and upper continental crust (UCC),and the magnitudes of trace element concentrations among them are different in the general order of plant<soil<UCC. Sandy soil has trace element concentrations with 1～2 orders of magnitudes less than those of the average UCC,while plant has 1～3 orders of magnitudes less than UCC and 1～2 orders less than the soil. The total trace element contents are not significantly different between root and needle,but significantly different between branch and root and between branch and needle. Those of root or needle are about 2 times of those of branch. Ag,Cd,In,Sn and Tl are enriched in C. equisetifolia,especially Ag.

Geochemical Characteristics of the Trace and Rare Earth Elements in Reef Carbonates from the Xisha Islands(South China Sea): Implications for Sediment Provenance and Paleoenvironment

Based on the concentrations of the trace elements,rare earth elements(REE),and Sr isotopic compositions in reef carbonates from the well‘Xike-1’reef core of the Xisha Islands,the constraints on sediment provenance and paleoenvironment were defined.Variations of the terrigenous input into the paleoseawater were traced in detail and the paleoenvironment and sediment provenance were further investigated.The results show that the HREE/LREE values in the reef carbonates are negatively associated with their Th and Al concentrations;however,their Al and Th concentrations show positive correlation.The lowest 87 Sr/86 Sr values in the reef carbonates generally coincide with the lowest values of Al,Th concentrations and the highest values of HREE/LREE.These data indicate that the HREE/LREE,Al concentrations,and Th concentrations of the reef carbonates are useful indexes for evaluating the influence of the terrigenous inputs on the seawater composition in the study area.From top to bottom,the changing process of the HREE/LREE values and Al,Th concentrations can be divided into 6 intervals;they are H1(0–89.30 m,about 0–0.11 Myr),L1(89.30–198.30 m,about 0.11–2.2 Myr),H2(198.30–374.95 m,about 2.2–5.3 Myr),D(374.95–758.40 m,about 5.3–13.6 Myr),L2(758.40–976.86 m,about 13.6–15.5 Myr),and H3(976.86–1200.00 m,about 15.5–21.5 Myr).Moreover,the changing trend of the HREE/LREE values coincides with that of the seawater δ^13C values recorded by benthonic foraminiferal skeletons from the drill core of ODP site 1148 in the South China Sea(SCS),but not with that of the seawaterδ18O values.The high uplifting rates of the Qinghai-Tibet Plateau coincide with the high Th and Al concentrations and the low HREE/LREE values in the reef carbonates.These data indicate that the main factors controlling the changes of terrigenous flux in the SCS are the tectonic activities associated with Qinghai-Tibet Plateau uplifting and the variations of uplifting rates rather than paleoclimatic changes.

Characteristics of Rare Earth and Trace Element Patterns in Bedded Cherts from the Bottom of the Lower Cambrian in the Northern Tarim Basin, Northwest China and Their Genetic Significance

The sedimentary sequence of the Lower Cambrian is a key interval to reveal the early evolution history of the Earth and there occur widespread cherts worldwide. These cherts possibly carry important information to decipher the breakup process of the Rodinia Continent. Black rock series at the bottom of the Lower Cambrian in the Northern Tarim Basin, China, is composed of black shales interbedded with thin-bedded cherts. Ten chert samples were systematically collected from two outcrops at Xiaoerbulak and Sogatbulak, 8.8 and 7.5 m thick respectively. The cherts were crushed, and were analyzed for trace element and rare earth concentrations. Trace elements such as V, Cu, Zn, U, Pb, Ba, Cd, Ag, Mo, As and Sb are highly enriched, and others such as Rb, Zr, Cs, Hf, Ta, W, Tl, Bi and Th are highly depleted in the cherts. These trace element patterns suggest that the cherts may be of deep crustal origin. The low ratios of Th/U and Rb/Sr further suggest that the cherts are of earth interior sources or received hydrothermal input during their deposition. Chondrite- normalized Eu/Eu* value markedly decreases upward in the section from 5.54 at the lowermost to 0.73 at the top, and NASC-normalized Eu/Eu* value decreases from 8.05 to 1.03. The relatively high Eu/Eu* ratio for the cherts from the northern Tarim Basin is most likely due to a hydrothermal input (e.g., Eu/Eu* ~10). The systematic decrease of Eu/Eu* ratio from the bottom to the top of the section reflects that the hydrothermal input is the largest in the lowermost portion of the section and gradually decreases upward. The chondrite-normalized Ce/Ce* ratio ranges from 0.42 to 0.83, with an average of 0.60. North American Shale Composite (NASC)-normalized Ce/Ce* ratio ranges from 0.42 to 0.79, with an average of 0.57. Negative Ce anomalies are distinct. ΣREEs in the cherts generally increase from 10.50 ppm at the bottom to 35.97 ppm at the top of the sampled section. NASC-normalized (La/Lu) N ratio decreases from 2.72 at the bottom to 0.67 at the top. NASC-normalized (La/Ce) N ratio increases from 1.36 at the bottom to 3.13 at the top. These REE patterns are very similar to those for the cherts deposited in the pelagic ocean-basin floor in the Franciscan Complex exposed at Marin Headlands, California (F-MH chert) (Murray et al., 1991). These geochemical signatures are inconsistent with our previous sedimentological data, which suggests a continental shelf setting. Based on multiple lines of evidence including high TOC content in the concomitant black shales, phosphorite at the bottom of black rock series, regional rise of sea level, and beginning of the southern Tianshan Ocean geotectonic cycle, the authors infer that the hydrothermal fluid was carried to the continental shelf by upwelling from a divergent pelagic ocean floor setting.

Rare-earth and trace elements and hydrogen and oxygen isotopic compositions of Cretaceous kaolinitic sediments from the Lower Benue Trough, Nigeria: provenance and paleoclimatic significance

This study evaluated the Cretaceous(Campanian–Maastrichtian) kaolinitic sediments of the Ajali/Mamu and Enugu/Nkporo Formations from the Lower Benue Trough of Nigeria. A combined method of inductively coupled plasma–mass spectrometry and isotope ratio mass spectrometry was used to investigate trace and rareearth element geochemistry and hydrogen and oxygen isotopic compositions. These data were then used to infer the sediments' provenance and paleoclimatic conditions during their deposition. The sediments contained low concentrations of most trace elements, with the exceptions of Zr(651–1352 ppm), Ba(56–157 ppm), V(38–90 ppm),and Sr(15.1–59.6 ppm). Average values of Co and Ni were1.5 and 0.7 ppm, respectively. Trace and rare earth element values were lower than corresponding values for upper continental crust and Post-Archean Australian Shale, with the exception of Zr. The samples showed only slight light rare-earth enrichment and nearly flat heavy rare-earth depletion patterns, with negative Eu and Tm anomalies,typical of felsic sources. Geochemical parameters such as La/Sc, Th/Sc, and Th/Co ratios support that the kaolinitic sediments were derived from a felsic rock source, likely deposited in an oxic environment.^(18 )O values ranged from+ 15.4 to + 21.2% for the investigated samples, consistent with a residual material derived from chemicalweathering of felsic rock and redeposited in a sedimentary basin(typical values of + 19 to + 21.2%). While in the basin, the sediments experienced extended interactions with meteoric water enriched in d D and d16 O. However,the variation in d D and d16 O values for the investigated samples is attributed to the high temperature of formation(54–91 °C). The d D and d^(18 )O values suggest that the sediments, although obtained from different localities within the Lower Benue Trough, formed under similar hot,tropical climatic conditions.

Rare-earth and trace element imprints on the origin and tectonic setting of gabbro-diorite complex in the Pan-African belt of Southeast Obudu Plateau,Nigeria

A gabbro-diorite plutonic complex from the Southeast Obudu Plateau, representing limited volumes of magma, was studied for its trace and rare-earth element characteristics, in an attempt to document its genetic and geodynamic history. Geochemical studies indicate that the gabbro samples are characterized by variable concentrations and low averages of such index elements as Cr (40×10-6–200×10-6; av. 80×10-6), Ni (40×10-6–170×10-6; 53.33×10-6) and Zr (110×10-6–240×10-6; 116.67×10-6); variable and high averages of Rb (3×10-6–270×10-6; 80.67×10-6), Sr (181×10-6–1610×10-6; 628.17×10-6) and U (0.14×10-6–3.46×10-6; 1.51×10-6), and fairly uniform Co (34×10-6–49×10-6; 36.33×10-6) and Sc (23×10-6–39×10-6; 34.5×10-6), while the diorite samples exhibit higher trace element compositions. The range of REE contents and distinctive chondrite-normalized patterns indicate moderate fractionation with slight positive Eu anomaly in the diorites to very low fractionation with flat patterns and slight positive Eu anomaly in the gabbros. However, the general element systematics of the samples, especially LILE (Ba, Rb, Sr, Cs and Pb), HFSE (Zr, Th, U, Hf, Mo, W, Nb and Sn), relatively immobile elements (Zr, Ni, Cr) and REE, suggests a differentiation model, involving fractional crystallization of olivine and clinopyroxene from a partial melt generated beneath an island arc complex. A possible model for the complex is therefore an island arc setting, the development of which was dominated by calc-alkaline magmatism across the Obudu Plateau.

Determination of 16 Rare Earth Elements in Banana by Microwave Digestion and ICP-MS

[Objective] This study aimed to investigate the residues of rare earth ele-ments in Guangxi banana from banana-producing area with application of rare earth fertilizers and evaluate the safety of using rare earth fertilizers in banana production. [Method] HNO3＋H2O2 mixed acid system with high pressure airtight microwave di-gestion sample pretreatment method and ICP-MS technology were used, to establish a determination method of 16 rare earth elements in banana samples, including Sc45, Y89, La139, Ce140, Pr141, Sm147, Eu153, Gb157, Tb159, Nd144, Dy163, Ho165, Er166, Tm169, Yb172 and Lu175. [Result] Different standard curves present-ed good linearity. Detection limit of the instrument was 0.002-0.01 μg/L; detection limit of the method was 0.1-0.6 μg/kg; recovery rate of standard addition was 94.5%-116%; relative standard deviation was 2.02%-14.21%. [Conclusion] This method has many advantages, such as simple mass spectrogram, high sensitivity and high selectivity, accurate quantification, high precision and accuracy, simple operation, high reproducibility and high recovery rate, which is suitable for the detection of rare earth elements in banana and other fruits, with certain theoretical and applicable val-ue for guiding banana production and high-efficient planting.

Effect of Different N Sources on Contents of Rare Earth and Trace Elements in Sclerotia of Pleurotus Tuber Regium

Effect of different N resource on the contents of rare-earth elements, P, K and trace elements in the sclerotia of Pleurotus tuber regium was studied. The results show that the contents of rare-earth elements, P, K and trace elements in the sclerotia of Pleurotus tuber regium are different when treating with various N sources. Except Er and Tm, the contents of rare-earth elements of La, Ho, Dy, Tb and Yb are the highest by treating with ammonium sulfate. When concerning the contents of P, K and trace elements in the sclerotia in different N source treatments, the contents of Cu and Fe are the highest by using cow dung as N source, In and P are the highest by using ammonium sulfate, K, Cl and S are the highest when using urea as N source. The correlation analysis show that certain correlation exists among the contents of rare-earth elements, P, K and trace elements in the sclerotia of Pleurotus tuber regium. Furthermore, the correlation is different by using different N sources, among which the content of Dy is positively related with the contents of P and In, Yb is highly positively related with P content and La is negatively related with S content.

A Geochemical Study of Rare Earth and Trace Elements in Cassiterite from Dachang Sn-Polymetallic Ore Field,Guangxi Province

Rare earth and trace elements are determined for cassiterite from a vein-type orebody , a lens and a sheeted-type orebody in the Dachang Sn-polymetallic ore field ,Guangxi Province .Cassiterite from the vein-type orebody has rare earth and trace dement characteristics similar to that of Dachang biotite granite of Late Yanshan age, showing an inheritable and a genetic relationship. Cassiterites from the kns and sheeted-vein orebody have rare earth and trace element characteristics greatly different from those of the vein-type cassiterite and the granite,showing distinctly higher contents of the ore-forming elements As, Sb,Zn,Ag etc.and a positive Eu anomaly and a negative Ce anomaly.The difference of rare earth and trace element characteristics for cassiterite from two kinds of orebodies reflects the compositional difference of ore-forming solutions. Authors suggest that the kns and sheeted-vein orebody was of nonmagmatic , mixed with underground hot brine origin , and that this kind of hot brine reacted with Devonian and Predevonian older strata and extraced some ore-forming metals from the strata and finaly empbced along the bedding and interbyer fracture zone etc. on its ascending way driven by the Indonisian orogenic movement . The vein-type orebody was formed chiefly by post-magmatic hydrothermal sobtions derived from magma differentiation of the Dachang biotite granite .