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Distribution and geochemical significance of trace elements in shale rocks and their residual kerogens

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Acta Geochimica 2018年第6期37卷 886-900页

作者： Jian-bing Xu Bin Cheng Qian Deng Yun-gan Liang Oluwabamise Lekan Faboya Ze-wen Liao Guangzhou Institute of Geochemistry Chinese Academy of SciencesGuangzhou510640China University of the Chinese Academy of Sciences Beijing100049China

There is a dearth of information about the distribution of trace elements in kerogen from shale rocks despite several reports on trace element composition in many shale samples. In this study, trace elements in shale rocks and their residual kerogens were determined by inductively coupled plasma–mass spectrometry. The results from this study show redox-sensitive elements relatively concentrated in the kerogens as compared to the shales. This may be primarily due to the adsorption and complexation ability of kerogen, which enables enrichment in Ni, Co, Cu, and Zn. For the rare earth elements(rees),distinct distribution characteristics were observed for shales dominated by terrigenous minerals and their kerogen counterparts. However, shales with less input of terrigenous minerals showed similar REE distribution patterns to their residual kerogen. It is speculated that the distribution patterns of the rees in shales and kerogens may be sourcerelated.

关键词： Shale Kerogen Trace elements rees

REE geochemistry of core sediments of Cauvery delta,India for provenance studies

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Acta Geochimica 2020年第4期39卷 512-526页

作者： Malik Zubair Ahmad Pramod Singh Department of Geology Satellite Campus LehUniversity of KashmirLehJammu&Kashmir 194104India Department of Earth Sciences School of Physical Chemical and Applied SciencesPondicherry UniversityKalapetPondicherry 605014India

The rare earth element(REE)geochemical composition of sediments from two cores were used to investigate the provenances of the Late Pleistocene to Holocene sediments of Cauvery delta,South India.The chondrite-normalized REE patterns and bi-variant plots of Th/Co vs.La/Sc and La/Th vs.Th/Yb indicated felsic source of sediments.Chondrite-normalized plots of REE in both cores are almost parallel and exhibit similar fractionation ratio(Ce/Yb)_N of^8.2.Furthermore,persistence in rees patterns implies either uniform source rocks and/or efficient homogenization of sediments during transportation and deposition.Chondrite-normalized patterns of the samples show enrichment of light rare earth elements and flat pattern of heavy rare earth elements;such patterns imply dominance of felsic composition rocks in the provenance.Further,these samples show quite resemblance with Charnockites and Gneisses of Palani and Kodaikanal hill areas.Chondrite-normalized REE patterns of the Pleistocene sediments of Uttrangudi core show similar abundance,fractionation,and Eu anomaly values as of selected samples from Tertiary rocks near southwest part of the delta.We attribute the increased input from this region to the upliftment because of tectonic activity and lowering of sea level during the Pleistocene.

关键词： Delta sediments rees Provenance Rainfall Relief

Concentration, Distribution, and Occurrence of rees in Coals from Chongqing,Southwest China

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Journal of China University of Mining and Technology 2005年第3期15卷 227-233页

作者： LI Da-hua TANG Yue-gang CHEN Kun DENG Tao CHENG Fang-ping LIU Dong Department of Resources and Earth Science China University of Mining ＆ Technology Beijing 100083 China Chongqing Coal Geology Institute Chongqing 400042 China

The concentration, distribution, and occurrence of rare earth elements (rees) in coals as well as stone coalsin different geological periods from Chongqing were studied. The results show that the REE content in coals fromChongqing is much higher than that of the ordinary Chinese coals, the Late Paleozoic coals from North China, UScoals, and the world coals. Although the concentration of light rare earth elements (LREE) is higher than that of heavyrare earth elements (HREE), the ratio of LREE to HREE is as low as 5.11. The REE content decreases with thecoal-formation periods from old to new. The REE content in the Sinian stone coal is the highest, but it is the lowest inEarly Jurassic coals. The similar REE contents in bituminous coals and anthracite show that the metamorphism has alittle influence on REE content in coal. In addition, silicate association dominates the occurrence mode of rees incoals from Chongqing.

关键词：西南地区重庆煤矿稀土元素 rees 地质条件

Distribution of rare earth elements of granitic regolith under the influence of climate

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Acta Geochimica 2017年第3期36卷 440-445页

作者： Hairuo Mao Congqiang Liu Zhiqi Zhao Junxiong Yang State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of SciencesGuiyang 550002 China University of Chinese Academy of Sciences Beijing 100049China

The distribution and anomalies of rare earth elements(rees) of granitic regolith were studied in Inner Mongolia and Hainan Island, China. One profile showed slight REE enrichment of an upper layer and no obvious light REE/heavy REE(LREE/HREE) fractionation(La_N/Yb_N of 0.9). The second profile was significantly enriched in rees and enriched in Lrees in the upper portion(La_N/Yb_N>1.8). Eu, Ce, and Gd anomalies of the two profiles are different. Slightly negative Eu, Ce, and Gd anomalies in NMG-3-1 indicate slow dissolution of primary minerals and little secondary products; in contrast, a positive Eu anomaly in HN-2 suggests the vegetation cycle may contribute to soil. The Ce anomaly of HN-2 reflects oxidation of Ce and coprecipitation by Fe-and Mn-oxides and organic matter. Correlation between Ce and Gd anomalies in HN-2 suggests Ce and Gd are both influenced by redoxreduction.

关键词：稀土元素分布花岗岩风化壳气候影响异常反映稀土富集 rees 铁锰氧化物文件显示

Genesis for Rare Earth Elements Enrichment in the Permian Manganese Deposits in Zunyi, Guizhou Province, SW China

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Acta Geologica Sinica(English Edition) 2020年第1期94卷 90-102页

作者： XU Hai GAO Junbo YANG Ruidong DU Lijuan LIU Zhichen CHEN Jun FENG Kangning YANG Guanghai College of Resources and Environmental Engineering Guizhou UniversityGuiyang 550025China Key Laboratory of Karst Georesources and Environment Ministry of EducationGuizhou UniversityGuiyang 550025China 102 Geological Team Guizhou Bureau of Exploration and Development of Geology Mineral ResourcesZunyiGuizhou 563003China Institute of Geochemistry Chinese Academy of SciencesGuiyang 550081China

The Zunyi manganese deposits, which formed during the Middle to Late Permian period and are located in northern Guizhou and adjacent areas, are the core area of a series of large-medium scale manganese enrichment minerogenesis in the southern margin and interior of the Yangtze platform, Southern China. This study reports the universal enrichment of rare earth elements(rees) in Zunyi manganese deposits and examines the enrichment characteristics, metallogenic environment and genesis of rees. The manganese ore bodies present stratiform or stratoid in shape, hosted in the silicon–mud–limestones of the Late Permian Maokou Formation. The manganese ores generally present lamellar, massive, banded and brecciated structures, and mainly consist of rhodochrosite, ropperite, tetalite, capillitite, as well as contains paragenetic gangue minerals including pyrite, chalcopyrite, rutile, barite, tuffaceous clay rock, etc. The manganese ores have higher ΣREE contents range from 158 to 1138.9 ppm(average 509.54 ppm). In addition, the ΣREE contents of tuffaceous clay rock in ore beds vary from 1032.2 to 1824.5 ppm(average 1396.42 ppm). The rees from manganese deposits are characterized by La, Ce, Nd and Y enriched, and existing in the form of independent minerals(e.g., monazite and xenotime), indicating Zunyi manganese deposits enriched in light rare earth elements(LREE). The Ceanom ratios(average-0.13) and lithofacies and paleogeography characteristics indicate that Zunyi manganese deposits were formed in a weak oxidation-reduction environment. The(La/Yb)ch, Y/Ho,(La/Nd)N,(Dy/Yb)N, Ce/Ce* and Eu/Eu* values of samples from the Zunyi manganese deposits are 5.53–56.92, 18–39, 1.42–3.15, 0.55–2.20, 0.21–1.76 and 0.48–0.86, respectively, indicating a hydrothermal origin for the manganese mineralization and rees enrichment. The δ13 CV-PDB(-0.54 to-18.1‰) and δ18 OSMOW(21.6 to 26.0‰) characteristics of manganese ores reveal a mixed source of magmatic and organic matter. Moreover, the manganese ore, tuffaceous clay rock and Emeishan basa

关键词： Genesis rees enrichment Hydrothemal origin Permian manganese deposits Zunyi

Rare Earth Elements Geochemistry of Sheikh-Marut Laterite Deposit,NW Mahabad,West-Azarbaidjan Province,Iran

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Acta Geologica Sinica(English Edition) 2013年第1期87卷 176-185页

作者： Ali ABEDINI Ali Asghar CALAGARI Geology Department Faculty of SciencesUrmia University Geology Department Faculty of Natural SciencesUniversity of Tabriz

Laterite deposit at Sheikh-Marut （NW occurred within middle-upper Permian carbonate Mahabad, West-Azarbaidjan province, Iran） rocks. It consists of seven stratiform and/or discontinuous lenticular layers extending over 4.2 km in length and having thicknesses ranging from 3 to 14 m. Mineralogical data show that the ores contain kaolinite and hematite as major and boehmite, diaspore, halloysite, amesite, anatase, and muscovite-illite as minor mineral phases. The computed Ce anomaly values in the ores range from 0.05 to 20.84. Conservative index （e.g., Eu/Eu＊） suggests that this deposit is a product of alteration and weathering of basaltic rocks. Rhythmic increment of EREE values of the ores with approaching to the carbonate bedrocks shows an in-situ occurrence of lateritization processes. Mass change calculations of elements indicate that two competing processes namely leaching and fixation were the major regulating factors in concentration variation of rees （La-Lu） in this deposit. The obtained results show that pH increase of weathering solutions by carbonate bedrocks, existence of organic matters, and the degree of comlexation with organic ligands played remarkable role in distribution of rees during lateritization. Further geochemical considerations revealed that secondary phosphates, Mn-oxides and -hydroxides, diaspore, and anatase were the potential hosts for rees in this deposit.

关键词： laterite geochemistry rees Sheikh-Marut deposit Mahabad Iran

Injective Dimension of rees Rings

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Science China Mathematics 1993年第12期36卷 1417-1421页

作者：王志玺 Department of Mathematics University of Science and Technology of China

Let A be a left and right Noetherian ring and let x be a central regular element of A. A_x denotes the localization of A at the central multiplicatively closed subset {1,x,x^2,…}. Suppose M is an A-module such that x is a nonzero divisor in. M. It is shown that there is an equality relation among three iniective dimensions ld_A(M), IdA_x(M_x), and I_dA/xA(M/xM). Then the result is applied to the case of rees rings of filtered rings and an improved and uniform form of the two results of E. K. Ekstrm is obtained. Moreover, the results in this paper generalize the relevant results of Li Huishi, M. Van den Bergh and F. Van Oystaeyen.

关键词： Noetherian ring injective dimension filtered ring rees ring

Variations of trace elements and rare earth elements(rees)treated by two different methods for snow-pit samples on the Qinghai-Tibetan Plateau and their implications

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Research in Cold and Arid Regions 2017年第6期9卷 656-667页

作者： YueFang Li Zhen Li Ju Huang Giulio Cozzi Clara Turetta Carlo Barbante LongFei Xiong State Key Laboratory of Cryospheric Science Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhouGansu 730000China University of Chinese Academy of Sciences Beijing 100049China Institute for the Dynamics of Environmental Processes National Research Council(IDPA-CNR)University of VeniceDorsoduro 213730123 VeniceItaly

Although previous investigations of the trace elements in snow and ice from the Qinghai-Tibetan Plateau obtained interesting information about pollution from human activities on the plateau, most were based on traditional acidification methods.To emphasize the influence of the different sample-preparation methods on the records of trace elements and rare earth elements, snow samples were collected from glaciers on the Qinghai-Tibetan Plateau in China and prepared using two methods: traditional acidification and total digestion. Concentrations of 18 trace elements(Al, Ti, Fe, Rb, Sr, Ba, V, Cr, Mn, Li,Cu, Co, Mo, Cs, Sb, Pb, Tl, and U), along with 14 rare earth elements(rees: La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er,Tm, Yb, and Lu), Y, and Th in the snow samples, were measured using inductively coupled plasma-sector field mass spectrometry(ICP-SFMS). The results showed that the mass fraction of the trace elements(defined as ratio of concentration in the acid-leachable fraction to that in the digested sample) such as Mo, Ti, Al, Rb, and V, varied from 0.06 to 0.5. The mass fraction of other trace elements varied from about 0.6 to more than 0.9; those of the rees, Y, and Th varied from 0.34 to0.75. Lower mass fractions will lead to an overestimated contribution of other sources, especially human activities, and the underestimated fluxes of these trace elements(especially rees, Y, and Th, as well as dust) if the rees are used as the proxy for the crust dust. The two sample-preparation methods exhibited different REE normalized distribution patterns,REE ratios, and provenance-tracing results. The REE normalized distribution patterns and proxies in the digested samples are more reliable and integrated than those found in traditional acidification method for dust-provenance tracing.

关键词： sample-preparation methods trace elements rees mass fraction snow samples Qinghai-Tibetan Plateau

Application of Self-Organizing Map for Exploration of rees’ Deposition

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Open Journal of Geology 2016年第7期6卷 571-582页

作者： Mohammadali Sarparandeh Ardeshir Hezarkhani Department of Mining and Metallurgical Engineering Amirkabir University of Technology (Tehran Polytechnic) Tehran Iran

Varieties of approaches and algorithms have been presented to identify the distribution of elements. Previous researches based on the type of problem, categorized their data in proper clusters or classes. This means that the process of solution could be supervised or unsupervised. In cases, where there is no idea about dependency of samples to specific groups, clustering methods (unsupervised) are applied. About geochemistry data, since various elements are involved, in addition to the complex nature of geochemical data, clustering algorithms would be useful for recognition of elements distribution. In this paper, Self-Organizing Map (SOM) algorithm, as an unsupervised method, is applied for clustering samples based on rees contents. For this reason the Choghart Fe-REE deposit (Bafq district, central Iran), was selected as study area and dataset was a collection of 112 lithology samples that were assayed with laboratory tests such as ICP-MS and XRF analysis. In this study, input vectors include 19 features which are coordinates x, y, z and concentrations of rees as well as the concentration of Phosphate (P2O5) since the apatite is the main source of rees in this particular research. Four clusters were determined as an optimal number of clusters using silhouette criterion as well as k-means clustering method and SOM. Therefore, using self-organizing map, study area was subdivided in four zones. These four zones can be described as phosphate type, albitofyre type, metasomatic and phosphorus iron ore, and Iron Ore type. Phosphate type is the most prone to rare earth elements. Eventually, results were validated with laboratory analysis.

关键词： Self Organizing Map (SOM) rees Geochemistry Choghart Central Iran