Rare and rare-earth elements in the metal-bearing coals of the north of the Lena Coal Basin

2016 ◽  
Vol 50 (2) ◽  
pp. 120-126 ◽  
Author(s):  
V. I. Kuz’min ◽  
V. N. Kuz’mina ◽  
P. N. Kuznetsov ◽  
S. M. Kolesnikova
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Coal Basin ◽  
The North

scholarly journals Rare Earth Elements (REE) in Claystones with Selected Coal Seams of the Mudstone and Sandstone Series of the Upper Silesian Coal Basin

2016 ◽  
Vol 32 (3) ◽  
pp. 39-66
Author(s):  
Magdalena Kokowska-Pawłowska
Keyword(s):  
Rare Earth ◽  
Chemical Composition ◽  
Rare Earth Elements ◽  
Inductively Coupled Plasma ◽  
Correlation Coefficients ◽  
Coal Seams ◽  
Coal Basin ◽  
High Positive Correlation ◽  
The North ◽  
Ignition Loss

AbstractIn this paper results of investigation on the variability of REE contents in the clayey rocks accompanying selected coal seams from Zaleskie and Ruda beds of western part of Upper Silesia Coal Basin (USCB) have been presented. 75 samples have been analysed from the claystones coexisting with coal seams 405 and 408 collected from the USCB area. Contents of selected REE have been assessed with a use of the Instrumental Neutron Activation Analysis (INAA). In regard to the constraints of this method following elements underwent evaluation: scandium (Sc), lanthanum (La), cerium (Ce), neodymium (Nd), samarium (Sm), Europium (Eu), terbium (Tb), ytterbium (Yb), and lutetium (Lu). Contents of yttrium (Y) was determined with a use of the Fusion-Inductively-Coupled Plasma (FUSICP) method.In all featured groups of claystone (claystone, sandy claystone and siderite claystone) the highest, although diverse content of SiO2, Al2O3, Fe2O3and K2O were observed. Whatever the petrographic character of the claystone rocks, among the analyzed rare earth elements, the highest participation of Ce, La, Y, Nd and Sc were found. Other analyzed REE showed significantly lower content. Some regional diversity of REE in the area of study was also observed. In the south-western part of the USCB, higher participation showed: Y, Sm and Nd, while in the north-western part: Sc. To determine the dependence between content of rare earth elements and chemical composition, the correlation-coefficients were calculated. In the calculations ratio SiO2/Al2O3and increased content of P2O5, ignition loss and Fe2O3were taken into account. Most of the elements analyzed in group of rocks distinguished by increased content of P2O5and ignition loss, showed high positive correlation with chemical composition. In almost all groups of rocks negative correlation with MnO, loss on ignition and sometimes with CaO was found. Rocks represented by siderite claystone are characterized by the highest values of correlation coefficients of rare earth elements with Fe2O3.

scholarly journals Geochemistry of Surface Sediments From the Emperor Seamount Chain, North Pacific

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Chen ◽  
Jianjun Zou ◽  
Aimei Zhu ◽  
Xuefa Shi ◽  
Dirk Nürnberg ◽  
...  
Keyword(s):  
Grain Size ◽  
Rare Earth ◽  
Rare Earth Elements ◽  
Water Depth ◽  
Surface Sediment ◽  
North Pacific ◽  
The North ◽  
Seamount Chain ◽  
The North Pacific ◽  
Emperor Seamount Chain

Investigating the composition and distribution of pelagic marine sediments is fundamental in the field of marine sedimentology. The spatial distributions of surface sediment are unclear due to limited investigation along the Emperor Seamount Chain of the North Pacific. In this study, a suite of sedimentological and geochemical proxies were analyzed, including the sediment grain size, organic carbon, CaCO3, major and rare earth elements of 50 surface sediment samples from the Emperor Seamount Chain, spanning from ∼33°N to ∼52°N. On the basis of sedimentary components, we divide them into three Zones (I, II, and III) spatially with distinct features. Sediments in Zone I (∼33°N–44°N) and Zone III (49.8°N–53°N) are dominated by clayey silt, and mainly consist of sand and silty sand in Zone II. The mean grain size of the sortable silt shows that the hydrodynamic condition in the study area is significantly stronger than that of the abyssal plain, especially at the water depth of 1,000–2,500 m. The CaCO3 contents in sediments above 4,000 m range from 20 to 84% but decrease sharply to less than 1.5% below 4,000 m, confirming that the water depth of 4,000 m is the carbonate compensation depth of the study area. Strong positive correlations between Al2O3 and Fe2O3, TiO2, MgO, and K2O (R > 0.9) in the bulk sediments indicate pronounced contributions of terrigenous materials from surrounding continent mass to the study area. Furthermore, the eolian dust makes contributions to the composition of bulk sediments as confirmed by rare earth elements. There is no significant correlation between grain size and major and minor elements, which indicates that the sedimentary grain size does not exert important effects on terrigenous components. There is significant negative δCe and positive δEu anomalies at all stations. The negative Ce anomaly mainly exists in carbonate-rich sediments, inheriting the signal of seawater. The positive Eu anomaly indicates widespread volcanism contributions to the study area from active volcanic islands arcs around the North Pacific. The relative contributions of terrestrial, volcanic, and biogenic materials vary with latitude and water depth in the study area.

Zircon U–Pb and molybdenite Re–Os dating and geological implications of the Shimadong porphyry molybdenum deposit in eastern Yanbian, northeastern China

2020 ◽  
Vol 57 (5) ◽  
pp. 630-646
Author(s):  
Xi-Tao Nie ◽  
Jing-Gui Sun ◽  
Feng-Yue Sun ◽  
Bi-Le Li ◽  
Ya-Jing Zhang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Lower Crust ◽  
Active Continental Margin ◽  
Major And Trace Elements ◽  
Northeastern China ◽  
Heavy Rare Earth ◽  
The North ◽  
Heavy Rare Earth Elements ◽  
Porphyry Mo Deposit

The Shimadong porphyry Mo deposit is located in eastern Yanbian, in the eastern part of the north margin of the North China craton, northeastern China. Here, we present the whole-rock major and trace elements, zircon U–Pb and Hf isotope data, and molybdenite Re–Os data for the Shimadong deposit. The porphyry was emplaced at 163.7 ± 0.9 Ma and the mineralization at 163.1 ± 0.9 Ma, suggesting that the mineralization was associated with the emplacement of the Shimadong porphyritic monzogranite. The porphyritic monzogranite had high SiO2 (70.09–70.55 wt%) and K2O + Na2O (7.98–8.27 wt%) contents and low MgO (0.51–0.53 wt%), TFeO (2.4–2.47 wt%), CaO (2.19–2.26 wt%), and K2O/Na2O (0.8–0.82) contents. The porphyry was rich in large ion lithophile elements Rb, Ba, K, and Sr, depleted in high-field-strength elements Y, Nb, Ta, P, and Ti, without significant Eu anomaly (δEu = 0.86–1.00), and depleted in heavy rare earth elements with light rare earth elements/heavy rare earth elements = 18.25–20.72 and (La/Yb)N = 27.10–34.67. These features are similar to those of adakitic rocks derived from a thickened lower crust. Zircon εHf(t) values for the porphyritic monzogranite ranged from –19.2 to 6.3, and the two-stage Hf model ages (TDM2) were 2421–811 Ma. These data indicate that the primary magma of the Shimadong porphyritic monzogranite was mainly derived from partial melting of the thickened lower crust consisting of juvenile crust and pre-existing crust. Combined with the results of previous studies, our data suggest that the Shimadong porphyry Mo deposit was emplaced along an active continental margin related to the westward subduction of the paleo-Pacific Plate.

Deformation-driven emplacement-differentiation in the Closepet pluton, Dharwar Craton, South India: an alternate view

2019 ◽  
Vol 489 (1) ◽  
pp. 261-274 ◽  
Author(s):  
Abhijit Bhattacharya
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
South India ◽  
Major Element ◽  
Volume Fraction ◽  
Dharwar Craton ◽  
The North ◽  
Magmatic Fabric ◽  
Melt Composition ◽  
Crystal Content

AbstractIn the Late Archean north-trending Closepet pluton, trains of euhedral K-feldspar phenocrysts and matrix-supported idiomorphic K-feldspar crystals in the central part of the pluton define oblique-to-pluton margin steep-dipping east/ENE-trending magmatic fabrics. The magmatic fabric is defined by phenocryst-rich and phenocryst-poor layers, with the euhedral porphyries continuous across the layers. The fabrics are near-orthogonal to the gently-dipping gneissic layers in the host gneisses. The fabrics curve adjacent to locally-developed north/NNE-trending melt-hosted dislocations parallel to the axial planes of horizontal/gently-plunging north-trending upright folds in the host gneisses. In the pluton interior, both fabrics in the intrusives formed at supra-solidus conditions, although the volume fraction of melts diminished drastically due to cooling/melt expulsion. At the pluton margin, the north-trending fabric is penetrative and post-dates magma solidification. Within the pluton, the major element oxides, rare earth elements, anorthite contents in plagioclase, and (Mg/Fe + Mg) ratios in biotite decrease with increasing SiO2 from phenocryst-rich (up to 75% by volume) granodiorite to phenocryst-poor (<15 vol%) granite that broadly correspond to minimum melt composition. The chemical-mineralogical variations in the pluton is attributed to deformation-driven ascent of magma with heterogeneous crystal content, ascending at variable velocities (highest in crystal-poor magma) along oblique-to-pluton margin east/ENE-trending extensional fractures induced by dextral shearing.

scholarly journals Petrografia, Geoquímica, Análises Isotópicas (Sr, Nd) e Geocronologia Ar-Ar dos Basaltos de Tapirapuã (Tangará da Serra, Mato Grosso, Brasil)

2006 ◽  
Vol 33 (2) ◽  
pp. 71 ◽  
Author(s):  
MÁRCIA APARECIDA DE SANT’ANA BARROS ◽  
ANA MARIA MIZUSAKI ◽  
RICARDO WESKA ◽  
ANDRÉ DE BORBA ◽  
FARID CHEMALE JR ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
North Atlantic ◽  
Volcanic Event ◽  
Mato Grosso ◽  
Fine Grained ◽  
The North ◽  
Tectonic Environment ◽  
Heavy Rare Earth Elements ◽  
Light Rare Earth Elements

 The basaltic flows from Tapirapuã Formation are exposed at Tangará da Serra region, 250 km from Cuiabá (MT) and the thickness can reach 310 meters. The basalts range from massive dark gray, with colunar disjunctions at the base to purple amygdaloidal at the top. They are generally fine-grained, however gabroics portions have been identified. In thin section the Tapirapuã basalts show subophitic texture. Chemical analyses in these rocks suggest tholeiitic compositions, within continental tectonic environment. There is an enrichment of light rare earth elements when compared to heavy rare earth elements. The studied samples have low contents of TiO2 and P2O5 being similar to low P2O5 and TiO2 group from Serra Geral Formation (Paraná Basin). Analyses of Sr and Nd isotopes show the following results: 87Sr/86Sr between 0.703 and 0.707, ∈Nd from –0.01 to + 2.32 and model ages (TDM)= (931 to 1.267 Ma). 40Ar / 39Ar geochronology of plagioclase crystals from Tapirapuã basalts presented a plateau age of 206 ± 6 Ma, in agreement with previous ages obtained from Anari and Tapirapuã sub-provinces. This result places the volcanic event at the limit of the Triassic-Jurassic periods, related to the opening of the North Atlantic.

scholarly journals Metallogenic Epoch and Tectonic Setting of Saima Niobium Deposit in Fengcheng, Liaoning Province, NE China

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 80 ◽  
Author(s):  
Nan Ju ◽  
Yun-Sheng Ren ◽  
Sen Zhang ◽  
Zhong-Wei Bi ◽  
Lei Shi ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Nepheline Syenite ◽  
Large Scale ◽  
Tectonic Setting ◽  
Liaoning Province ◽  
Late Triassic ◽  
Ne China ◽  
The North ◽  
Heavy Rare Earth Elements

The Saima deposit is a newly discovered niobium deposit which is located in the eastern of Liaoning Province, NE China. Its mineralization age and geochemical characteristics are firstly reported in this study. The Nb orebodies are hosted by the grey–brown to grass-green aegirine nepheline syenite. Detailed petrographical studies show that the syenite consists of orthoclase (~50%), nepheline (~30%), biotite (~15%) and minor arfvedsonite (~3%) and aegirine (~2%), with weak hydrothermal alteration dominated by silicification. In situ LA-ICP-MS zircon U-Pb dating indicates that the aegirine nepheline syenite was emplaced in the Late Triassic (229.5 ± 2.2 Ma), which is spatially, temporally and genetically related to Nb mineralization. These aegirine nepheline syenites have SiO2 contents in the range of 55.86–63.80 wt. %, low TiO2 contents of 0.36–0.64 wt. %, P2O5 contents of 0.04–0.11 wt. % and Al2O3 contents of more than 15 wt. %. They are characterized by relatively high (K2O + Na2O) values of 9.72–15.51 wt. %, K2O/Na2O ratios of 2.42–3.64 wt. % and Rittmann indexes (σ = [ω(K2O + Na2O)]2/[ω(SiO2 − 43)]) of 6.84–17.10, belonging to the high-K peralkaline, metaluminous type. These syenites are enriched in large ion lithophile elements (LILEs, e.g., Cs, Rb and Ba) and light rare earth elements (LREEs) and relatively depleted in high field strength elements (HFSEs, e.g., Nb, Zr and Ti) and heavy rare earth elements (HREEs), with transitional elements showing an obvious W-shaped distribution pattern. Based on these geochronological and geochemical features, we propose that the ore-forming intrusion associated with the Nb mineralization was formed under post-collision continental-rift setting, which is consistent with the tectonic regime of post-collision between the North China Craton and Paleo-Asian oceanic plate during the age in Ma for Indosinian (257–205 Ma). Intensive magmatic and metallogenic events resulted from partial melting of lithospheric mantle occurred during the post-collisional rifting, resulting in the development of large-scale Cu–Mo mineralization and rare earth deposits in the eastern part of Liaoning Province.

scholarly journals The role of sulfate-rich fluids in heavy rare earth enrichment at the Dashigou carbonatite deposit, Huanglongpu, China

2019 ◽  
Vol 84 (1) ◽  
pp. 65-80 ◽  
Author(s):  
Delia Cangelosi ◽  
Martin Smith ◽  
David Banks ◽  
Bruce Yardley
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Fluid Inclusions ◽  
Central China ◽  
Open Pit ◽  
Secondary Phases ◽  
Heavy Rare Earth ◽  
The North ◽  
Heavy Rare Earth Elements ◽  
Total Sulfate

AbstractThe Huanglongpu carbonatites are located in the north-western part of the Qinling orogenic belt in central China. Calcite carbonatite dykes at the Dashigou open pit are unusual due to their enrichment in heavy rare earth elements (HREE) relative to light rare earth elements (LREE), leading to a flat REE pattern, and in that the majority of dykes have a quartz core. They also host economic concentrations of molybdenite. The calcite carbonatite dykes show two styles of mineralogy according to the degree of hydrothermal reworking, and these are reflected in REE distribution and concentration. The REE in the little-altered calcite carbonatite occur mostly in magmatic REE minerals, mainly monazite-(Ce), and typically have ΣLREE/(HREE+Y) ratios from 9.9 to 17. In hydrothermally altered calcite carbonatites, magmatic monazite-(Ce) is partially replaced to fully replaced by HREE-enriched secondary phases and the rocks have ΣLREE/(HREE+Y) ratios from 1.1 to 3.8. The fluid responsible for hydrothermal REE redistribution is preserved in fluid inclusions in the quartz lenses. The bulk of the quartz lacks fluid inclusions but is cut by two later hydrothermal quartz generations, both containing sulfate-rich fluid inclusions with sulfate typically present as multiple trapped solids, as well as in solution. The estimated total sulfate content of fluid inclusions ranges from 6 to >33 wt.% K2SO4 equivalent. We interpret these heterogeneous fluid inclusions to be the result of reaction of sulfate-rich fluids with the calcite carbonatite dykes. The final HREE enrichment is due to a combination of factors: (1) the progressive HREE enrichment of later magmatic calcite created a HREE-enriched source; (2) REE–SO42– complexing allowed the REE to be redistributed without fractionation; and (3) secondary REE mineralisation was dominated by minerals such as HREE-enriched fluorocarbonates, xenotime-(Y) and churchite-(Y) whose crystal structures tends to favour HREE.

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