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Origin of Dispersed Organic Matter within Sandstones and Its Implication for uranium mineralization:A Case Study from Dongsheng uranium Ore Filed in China

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Journal of Earth Science 2022年第2期33卷 325-341页

作者： Fan Zhang Yangquan Jiao Shuangming Wang Liqun Wu Hui Rong Key Laboratory of Tectonics and Petroleum Resources China University of GeosciencesMinistry of EducationWuhan 430074China School of Earth Resources China University of GeosciencesWuhan 430074China Xi’an University of Science and Technology Xi’an 710054China

Carbonaceous debris(CD),common dispersed organic matter(i.e.,DOM),is widely disseminated in sandstones from uranium-bearing strata from the Dongsheng uranium ore field of the northern Ordos Basin.Compositions of maceral,element and biomarkers of CD were investigated through a series of methods with optical microscope,elemental analyzer and gas chromatography-mass spectrometry analyses(GC-MS)to study origin of CD.The results show that CD,centrally distributed nearby channel erosion surface,decreases with the increased distances to channel erosion surface,which indicates the CD might be related to the coal seam from the upper unit of the J2y Formation or synsedimentary plant from the J2z Formation.Macerals of CD are composed of vitrinite(i.e.,V),inertinite(i.e.,I),and minerals,including that V is primary.Compared with the coals from the J2y Formation classed into vitrinertite-V(V+I>95%,V>I),CD is grouped into vitrite(V>95%).Although,CD and coal are similar in element composition,the former is of lower organic carbon,H,N,and higher S.The(C27+C29)/(C31+C33)ratios of n-alkanes biomarkers indicate that the percentage of woody plants accounting for vegetation composition of CD predominate over that of coal,which is also evidenced by the higher C/N ratios and oleanane contents of CD.The evidence is also supported by plant branch buried in sandstones.The distribution characteristics of CD and differences in vegetation types between CD and coal suggest that CD might be not from the coal seam from J2y.The tissue preservation index,gelification index,ground water level index,and vegetation index reflect that the paleoenvironment of CD is controlled by fluctuating water,which is also supported by the existences of round CD.Compared with peat,sedimentary paleoenvironment where CD deposits is of weaker reducibility,higher salinity by analyzing Pr/Ph ratios and gammacerane index.Distributions of n-alkanes carbon number of CD with the presence of unknown complex mixtures show that microbial activities exist in sand bodies.Differe

关键词： carbonaceous debris vegetation types palaeoenvironment uranium mineralization Ordos Basin ore deposit geology

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Sequence Stratigraphy of the Lower Cretaceous Uraniferous Measures and mineralization of the Sandstone-hosted Tamusu Large uranium Deposit,North China

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Acta Geologica Sinica(English Edition) 2022年第1期96卷 167-192页

作者： LIU Bo SHI Zhiqiang PENG Yunbiao ZHANG Pengfei LI Peng Institute of Sedimentary Geology Chengdu University of TechnologyChengdu 610059China Geologic Party No.208 China Nuclear GeologyBaotouInner Mongolia 014010China

The Bayingobi basin is the Mesozoic-Cenozoic basin in North China in which the Tamusu uranium deposit is located.The ore-target layer of the deposit is the Lower Cretaceous Bayingobi Formation,which developed as a fan deltashallow lacustrine deposit.The distributary channel sand body of the fan delta plain and the underwater distributary channel sand body of the fan delta front formed a favorable uranium reservoir,so the study of sequence stratigraphy is extremely important to understanding the genesis of uranium deposits.On the basis of field investigation and a large number of borehole logs,the high resolution sequence stratigraphy of the Lower Cretaceous is divided and the system tracts of different periods are established.The relationship between deposition,interlayer oxidation and uranium enrichment is discussed.The Lower Cretaceous Bayingobi Formation can be divided into two fourth-order sequences(Sq1 and Sq2).The lower member of the Bayingobi Formation is referred to as Sq1,which is composed of a falling-stage system tract(FSST)on top.On the other hand,the upper member of the Bayingobi Formation is referred to as Sq2,which is composed of a lowstand system tract(LST),transgressive system tract(TST)and highstand system tract(HST).The lowstand system tract forms a favorable stratigraphic structure(mud-sand-mud formation)with the lacustrine mudstone of the overlying transgressive system tract,that is conducive for the migration of uranium-bearing oxygen water.The organic matter and pyrite in the fan delta sand body,as well as the dark mudstone in the distributary bay,provided a reducing medium for uranium mineralization.The ore body mainly occurs in the distributary channel,underwater distributary channel or the mouth bar of the fan delta.As a result of the moderate thickness,high permeability,favorable barrier and rich reducing medium,the rich ore body mainly occurs in the underwater distributary channel and mouth bar sand body of the delta front.Based on study of the sequence stratigraphy,the model of the se

关键词： Bayingobi Formation sequence stratigraphy fan delta uranium mineralization Tamusu uranium deposit

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The possible source of uranium mineralization in felsic volcanic rocks,Eastern Desert,Egypt of the Arabian-Nubian Shield:Constraints from whole-rock geochemistry and spectrometric prospection

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Acta Geochimica 2021年第5期40卷 819-845页

作者： Gehad.M.Saleh Bahaa.M.Emad Ibrahim.B.Abdel Kader Rania.M.Sakr Nuclear Materials Authority El MaadiP.O.Box 530CairoEgypt

The present work deals with the detailed geology,mineralogy,geochemistry,and spectrometric prospection of the felsic volcanic rocks at the Eastern Desert,Egypt of the Arabian-Nubian Shield.Felsic volcanic rocks are an essential source for rare earth elements(REEs)and uranium occurrences in this area.They are compositionally uniform with tholeiitic to calc-alkaline affinities,peraluminous and belong to the series of rhyolite with high-K melt.They exhibit more enrichment in high field strength elements(HFSE,e.g.Zr,Ta,Nd,Th,and U)and large-ion lithophile elements(LILE,e.g.Pb and Rb)compared to the country rocks of the studied area,with REE ranging from 188.20 to 442.70 ppm and strong depletion in Ti,Sr,P with deep negative Eu oddities.The felsic volcanic rocks were mostly generated from the partial melting of quartz-amphibolite facies accreted during the Neoproterozoic.Positive oddities of Zr-U-Th for the felsic volcanic rocks determine the involvement of crustal materials.Felsic volcanic rocks are found in A-type suites of magma and represent highly fractionated rocks derived from rhyolitic magma,with insignificant interaction with continental crust in the low-pressure environment and during fractional crystallization.Felsic volcanic rocks have higher values of radioactivity in which eU range from 0.5 to 121 ppm and eTh from 1.0 to 415.10 ppm.The high values of eU and eTh can be ascribed to the mineralization of uranium and the presence of accessory minerals of radiogenic nature such as uranophane,uranothorite,zircon,and monazite.Uranophane is considered as the mineral with most enriched uranium contents in the studied felsic volcanic rocks in which(UO2=87.30 wt%).Also,they are enriched with REE-bearing accessory minerals comprising allanite,titanite,and apatite.The geological investigations of the felsic volcanic rocks in the studied areas are inappropriate to clear the feasible economic potentialities of rare earth elements and U occurrences;itemized and invaluable explorational work is as yet needed.Whilst,the e

关键词： Felsic volcanic rocks Geochemistry REE uranium mineralization Egypt Arabian-Nubian Shield

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Timing of uranium mineralization and Geological Implications of Shazijiang Granite-Hosted uranium Deposit in Guangxi, South China: New Constraint from Chemical U-Pb Age

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Journal of Earth Science 2015年第6期26卷 911-919页

作者： Jincheng Luo Ruizhong Hu Shaohua Shi State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences University of Chinese Academy of Sciences Hunan Institute of Geological Survey

Miaoershan（MES） uranium ore field is one of the most important uranium sources in China, hosts the largest Chanziping carbonaceous-siliceous-pelitic rock type uranium deposit in South China together with many other granite-hosted uranium deposits. The Shazijiang（SZJ） uranium deposit is one of the representative granite-hosted uranium deposits in the MES uranium ore field, situated in the Ziyuan, Guangxi Province, South China. uranium mineralization in the SZJ deposit mainly occurs as uraninite with quartz and calcite veins that is spatially associated with mafic dykes in the region. The hydrothermal alteration includes silicification, carbonation and hematitization. New uraninite chemical U-Pb geochronology and petrographic evidences provide the timing constraints and new insights into the formation of the SZJ uranium deposit. The results show that the first stage of uranium mineralization formed at 97.5±4.0 Ma, whereas another stage of uranium mineralization occurred at 70.2±1.6 Ma. Two stages of uranium mineralization are fairly consistent with two episodic crustal extensions that occurred at -100 and -70 Ma throughout South China. This study indicates that there are two uranium mineralization events in SZJ uranium ore field controlled by mafic dyke, supporting that mafic dykes play an important topochemical role in uranium concentration and/or mobilization. Therefore, geochemical U-Pb age firstly reinforces that ore-forming age of the SZJ uranium deposit mainly yields at 97.5±4.0 and 70.2±1.6 Ma. Additionally, geochemical age method is particularly useful for interest samples which record information on multi-stage uranium mineralizations in South China.

关键词： Shazijiang uranium deposit uraninite U-Pb age EMPA uranium mineralization crustal extension South China.

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Characteristics of uranium mineralization in Red Clastic Formations in the Southwestern Margin of the Ordos Basin

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Acta Geologica Sinica(English Edition) 2020年第5期94卷 1471-1487页

作者： ZHANG Zilong HE Feng YI Longsheng FAN Honghai CAI Yuqi LIU Hongxu LIU Xinyang CHEN Hongbin JIA Cui YANG Mengjia Key Laboratory of uranium Resource Exploration and Evaluation Technology(CNNC) Beijing Research Institute of Uranium GeologyBeijing 100029China China National uranium Corp. Beijing 100013China No.203 Research Institute of CNNC XianyangShaanxi 712000China

In the southwestern margin of the Ordos Basin,uranium mineralization is primarily hosted by predominantly oxidative red clastic formations in the Lower Cretaceous.The main target layers for uranium exploration are the Madongshan and Liwaxia formations of the Liupanshan Group,followed by the Jingchuan Formation of the Zhidan Group.The host rocks(medium-fine feldspar quartz sandstone),which are bleached to a light grayish white color,contain a minor organic matter component and pyrite.uranium mineralization changes from surficial infiltration or phreatic oxidation in the upper part to interlayer oxidation in the lower part.uranium ore bodies are mostly lenticular or tabular in shape,locally shaped like crescent rolls.Individual ore bodies are typically small and shallow.uranium predominantly manifests as pitchblende and coffinite.Coffinite is usually short and columnar or granular in habit,whereas pitchblende occurs as an irregular colloidal covering on the surface or in fissures of ferric oxide,silicate,clay or carbonate.Secondary uranium minerals are torbernite,uranophane,and uranopilite.Minerals associated with uranium are mainly pyrite,chalcopyrite and,to a minor extent,arsenopyrite and fluorite.The associated elements are Mo,V,Se,Co,Ni,and Mn,the host sandstone being high in Cu and Ba.Overall,the red clastic formations in the southwestern margin of the Ordos Basin are characterized by’five multiples but one low’which means multiple target layers,multiple stages of mineralization,multiple ore body shapes,multiple kinds of uranium minerals,multiple associated elements,but low organic matter.This implies an overall complex uranium metallogenic environment and mineralization process.It is recommended that future uranium exploration should take into consideration regional metallogenic conditions and mineralization features,with target layers in the wide-smooth synclinal slope being focused on.Most uranium deposits are small to medium in size,and the main type of uranium mineralization can vary by target layer.

关键词： red clastic formation uranium mineralization Lower Cretaceous southwestern Ordos Basin

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Geochemical Characteristics of Rare Earth Elements of Guidong Granitic Complex and Relationship with uranium mineralization

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Journal of Rare Earths 2007年第S2期25卷 313-319页

作者：张展适华仁民刘晓东邓平吴烈勤 Key Laboratory of Nuclear Resources and Environment (East China Institute of Technology) Ministry of Education State Key Laboratory for Mineral Deposit Research Nanjing University No.290 Research Institute China National Nuclear Corporation

Guidong granitic complex is constituted by Luxi intrusion, Xiazhuang intrusion, Maofeng intrusion, Sundong intrusion, Aizi intrusion and Siqian intrusion, which emplaced in Indosinian and early Yanshanian Periods. These intrusions varied from each other not only in major element content, aluminium saturation index, but also in values of ∑REE, δEu, and LREE/HREE, (La/Yb)N, (La/Sm)N and (Gd/Yb)N. The Maofeng intrusion, which has the closest relationship with uranium mineralization, belongs to strong peraluminous granites. Having undergone much intense fluid-rock interaction, it is characterized by typical M-type tetrad effects and lowest values of ∑REE, δEu, LREE/HREE, (La/Yb)N, (La/Sm)N and (Gd/Yb)N ratios than other studied intrusions.

关键词： Guidong granitic complex fluid-rock interaction tetrad effects uranium mineralization Maofeng intrusion Rare earths

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Geological and Geochemical Features of uranium mineralization in Western Turkey

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International Journal of Geosciences 2016年第3期7卷 409-424页

作者： Leyla Kalender Ömer Nedim Alçiçek Ezgi Gürgenç Department of Geological Engineering Firat University Elazig Turkey Mineral Research and Exploration Institute Ankara Turkey

The purpose of this study is to determine the distribution and geochemical features of uranium mineralization in the Ragillar region in the Manisa-Koprübasi in western Turkey. Sixteen whole rock samples were collected from sites showing the highest levels of radioactivity (7600 cps) as measured by a gamma spectrometer in the dolomitic limestones. SEM-EDS (Scanning Electron Microscopy-Energy Dispersive Spectrometry), XRF (X-Ray Fluorescence), an ICP-OES (Inductively Coupled Plasma Optic Emission Spectrometer), and a Leco carbon-sulfur analyzer were used to determine the mineralogical and chemical characteristics of the whole rock samples. The mineralogical features showed that uranium mineralization is associated with fluorapatite-rich rocks formed within calcite matrix fractures;cracks systems;and limestone, claystone, marl and silicified breccia zones in the lacustrine sediments that are observed around the Kale crest dolomitic limestones in the Demirci basin. The geochemical data for these samples show a strong positive correlation between uranium and P2O5 concentrations. The geochemical data also indicate that uranium is deposited in the oxidation zone by dissolving the primary minerals (banded gneisses from the Menderes Massif, and dacitic and andesitic tuff) and moving the metal-rich hydrothermal fluids as phosphorus compounds, before passing through fractures, cracks, and permeable sandstone units, or along carbonate and clay layers.

关键词： Geochemistry Ra??llar uranium mineralization Turkey

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Roles of Multisourced Fluids in the Formation of Sandstone-Hosted uranium Deposits in the SW Songliao Basin, NE China

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Journal of Earth Science 2023年第1期34卷 54-69页

作者： Zhibing Feng Fengjun Nie Li Jiang Fei Xia Jianfang Cai Bocheng Zhang Yayun Lu Liangliang Zhang State Key Laboratory of Nuclear Resources and Environment East China University of TechnologyNanchang330013China Jiangxi Engineering Laboratory on Radioactive Geoscience and Big Data Technology East China University of TechnologyNanchang330013China Radioactive Geology and Exploration Technology Laboratory East China University of TechnologyNanchang330013China No.243 Geological Party China National Nuclear CorporationChifeng024000China Airborne Survey and Remote Sensing Center of Nuclear Industry China National Nuclear CorporationShijiazhuang050002China

The sandstone-hosted uranium deposits in the SW Songliao Basin differ from typical sandstone-hosted uranium deposits in terms of the geological features of the ore-deposits,including the geometry of the orebodies,mineral assemblage and petrography.Detailed drill core and microscopic observations,scanning electron microscopy(SEM),electron microprobe analysis(EMPA),heavy mineral concentrates,and fluid inclusion studies of the Upper Cretaceous Yaojia Formation,i.e.,the uranium-bearing layer,were integrated to investigate the roles of hydrothermal fluids in the formation of these uranium deposits.We found that the kaolinite alteration is developed in the mineralized zones,but it is less common in the peripheral areas.The fluid inclusions are hydrothermal fluids with a medium-low temperature(67 to 179 ℃) and a high salinity(5.9 wt.% to 20.1 wt.%).According to the analyses,three kinds of hydrothermal fluids,i.e.,the acid fluid,the groundwater heated by the mafic magma,and the alkaline fluid rich in Ca^(2+) and CO_(3)^(2-),were identified.The fluids might have low U content,but they have participated in the formation of the uranium deposits successively.Kaolinite formed by the acid-hydrothermal fluid absorbed large amounts of uranium.Subsequently,the thermal energy from the hydrothermal fluids changed the intrastratal redox environment and increased the solubility of the uranium minerals in the fluid.The alkaline-hydrothermal fluid rich in Ca^(2+) and C0_(3)^(2-) facilitated the formation of stable Ca-U(Ⅵ)-CO_(3) complex,which led to the enrichment of soluble uranium in solution,and final precipitation as pitchblende,brannerite and Ti-bearing uranium minerals in the uranium ores.

关键词： sandstone-hosted uranium deposit hydrothermal fluid uranium mineralization Songliao Basin kaolinite carbonate minerals

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Relations of uranium Enrichment and Metal Sulfides within the Shuanglong uranium Deposit,Southern Ordos Basin

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Journal of Earth Science 2022年第2期33卷 395-408页

作者： Yuhan Sun Yangquan Jiao LiqunWu Hui Rong Key Laboratory of Tectonics and Petroleum Resources China University of GeosciencesMinistry of EducationWuhan 430074China School of Earth Resources China University of GeosciencesWuhan 430074China

Large quantities of metal sulfides are widely distributed in uranium ores from the Middle Jurassic Zhiluo Formation of the Shuanglong uranium deposit,southern Ordos Basin,providing a convenient condition to study the relationship between metal sulfides and uranium minerals.The morphology and composition of uranium minerals and metal sulfides are illustrated to study uranium mineralization and mechanisms of metallogenesis.uranium minerals can be broadly categorized as pitchblende,coffinite and brannerite.Metal sulfides associated with uranium minerals are pyrite,sphalerite,chalcopyrite and galena.Some assemblages of various metal sulfides and uranium minerals indicate that they are coeval,but the order of formation is different.Based on mineralogical observations,paragenetic sequences for mineral assemblages are discussed.Alteration of Fe-Ti oxides forms Ti oxides,brannerite and pyrite.The formation of chalcopyrite was later than that of pyrite.Clausthalite(Pb Se)replaces sphalerite or shows isomorphism with galena.There are three genetic types of galena,of which typeⅠis related to tectonic thermal events and can interact with uranyl ions to form uranium oxides and Pb;.When sulfur activity is relatively high,Pb;can form new anhedral galena,that is,typeⅡ.TypeⅢof galena is related to the decay of uranium minerals.The genetic order of the main minerals was determined as follows:Fe-Ti oxides>Ti oxides/sphalerite/pyrite>clausthalite/galenaⅠ/chalcopyrite>galenaⅡ/uranium minerals>galenaⅢduring the diagenetic stage.Hydrogen sulfide(H;S)is a decisive factor in the interaction between metal sulfides and uranium.Metal ions can react with H;S,accompanied by precipitation and enrichment of uranium minerals.

关键词： uranium mineralization metal sulfides hydrogen sulfide paragenetic sequences Shuanglong uranium deposit ore deposit geology

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Geochemical Characteristics of Rare Earth Elements of Guidong Granitic Complex and Their Relationship with uranium mineralization

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Journal of Rare Earths 2005年第6期23卷 731-731页

作者： Zhang Zhanshi Hua Renmin Liu Xiaodong Deng Ping Wu Lieqin State Key Laboratory for Mineral Deposit Research Nanjing University Nanjing 210093 China Department of Geosciences and Geomatics East China Institute of Technology Fuzhou 344000 China Research Institute No. 290 Bureau of Geology China National Nuclear CorporationShaoguan .512026 China

The Guidong granitic complex is constituted by Luxi pluton, Xiazhuang pluton, Maofeng pluton, Sundong pluton, Aizi pluton and Siqian pluton, which intruded in Indosinian and early Yanshanian Periods. These plutons varies from each other not only in major element content, aluminium saturation index, but also in ∑REE, δEu, and LREE/HREE, （La/Yb）N, （La/Sm） N and （Gd/Yb） N ratios. uranium mineralization is mainly hosted by strong peraluminous granites, which has undergone intense fluid-rock interaction, and their REE compositions are characterised by M-type tetrad effects and lower ∑REE, δEu value, LREE/HREE, （La/Yb） N, （La/Sm） N and （Gd/Yb） N ratios.

关键词： Guidong granitic complex fluid-rock interaction tetrad effects uranium mineralization Maofeng pluton rare earths

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