Xiazhuang uranium ore field,located in the southern part of the Nanling Metallogenic Belt,is considered one of the largest granite-related U regions in South China.In this paper,we contribute new apatite fission track...Xiazhuang uranium ore field,located in the southern part of the Nanling Metallogenic Belt,is considered one of the largest granite-related U regions in South China.In this paper,we contribute new apatite fission track data and thermal history modeling to constrain the exhumation history and evaluate preservation potential of the Xiazhuang Uranium ore field.Nine Triassic outcrop granite samples collected from different locations of Xiazhuang Uranium ore field yield AFT ages ranging from 43 to 24 Ma with similar mean confined fission track lengths ranging from 11.8±2.0 to 12.9±1.9μm and Dpar values between 1.01 and 1.51μm.The robustness time-temperature reconstructions of samples from the hanging wall of Huangpi fault show that the Xiazhuang Uranium ore field experienced a time of monotonous and slow cooling starting from middle Paleocene to middle Miocene(~60-10 Ma),followed by relatively rapid exhumation in the late Miocene(~10-5 Ma)and nearly thermal stability in the Pliocene-Quaternary(~5-0 Ma).The amount of exhumation after U mineralization since the Middle Paleogene was estimated as~4.3±1.8 km according to the integrated thermal history model.Previous studies indicate that the ore-forming ages of U deposits in the Xiazhuang ore field are mainly before Middle Paleocene and the mineralization depths are more than 4.4±1.2 km.Therefore,the exhumation history since middle Paleocene plays important roles in the preservation of the Xiazhuang Uranium ore field.展开更多
The Sanjiu uranium ore field,located in the central of Zhuguangshan granitic batholith,is a newly discovered granite-related uranium ore field in South China.The main sulfide in the ore field is pyrite,which is closel...The Sanjiu uranium ore field,located in the central of Zhuguangshan granitic batholith,is a newly discovered granite-related uranium ore field in South China.The main sulfide in the ore field is pyrite,which is closely related to uranium mineralization.The textures major and trace elements,S-He-Ar isotopes compositions of pyrites in ores of different grade were observed and/or analyzed by optical microscope,scanning electron microscope,electron microprobe,laser ablation inductively coupled plasma mass spectrometry,and noble gas mass spectrometer(Helix-SFT).It is observed that these U-related pyrites are generally euhedral-subhedral with dissolution textures,anhedral variety with colloform texture veinlet and fine particles,and the color of the associated minerals is mostly dark hue,such as purple-black fluorite dark-red hematite,and dark-green chlorite,etc.The analytical results show that the average compositions of major elements in pyrite are FeS1.944.Pyrites are characterized by S-deficiency,low content of Co and Th,and Co/Ni>1which indicate that these ores are of low-temperature hydrothermal origin.We found that the higher the grade of ore,the more deficient in S,the more obvious negative δ^34S,and the higher REE content(close to U-rich granitic pluton)of pyrite.The S-He-Ar isotopic compositions of various varieties of pyrites indicate that the ore-forming fluids mainly come from crust-derived fluids and mixed with mantle-derived fluids.展开更多
In 2006, SOMAIR decided to increase the uranium production by 50% using heap leaching for the treatment of low grade ores. These ores, which come from different lodes with various properties, have been studied in four...In 2006, SOMAIR decided to increase the uranium production by 50% using heap leaching for the treatment of low grade ores. These ores, which come from different lodes with various properties, have been studied in four steps: ( 1 ) Lab tests: to compare the ores (characterization, acid consumptions, recovery...); (2) Column tests on an average sample: to define significant parameters for a feasibility study; (3) Column tests on specific samples: to optimize recovery for each ore and identify problems of percolation due to the clays; (4) Pilot tests in large boxes (stalls): to validate process parameters. Uranium production by heap leaching started in July 2009.展开更多
This study aims to assess the behavior of the release of Unat (i.e. uranium isotopes in natural relative abundance) from the release of water treated by the Ore Treatment Unit (UTM) in Caldas, state of Minas Gerais, B...This study aims to assess the behavior of the release of Unat (i.e. uranium isotopes in natural relative abundance) from the release of water treated by the Ore Treatment Unit (UTM) in Caldas, state of Minas Gerais, Brazil, during the years 1999 to 2009. During this period, the unit showed no industrial activity, except between 2004 and 2005, when UTM operated 400 tons of monazite in a process to obtain rare earths. Unat was analyzed by spectrophotometry once per week in the effluent waters at sampling point 014. Two fractions were considered for analysis: the soluble one (that passes through a 0.45 μm filter) and the particulate one (retained on a 0.45 μm filter). Statistical analyses were performed: the “Z” test and Pearson’s r2 correlation index. The values for the soluble fraction were consistently lower than those of the particulate fraction and no statistically significant correlation was observed between the soluble and particulate fractions. However, the particulate and the total fractions (the sum of soluble and particulate) strongly correlated.展开更多
In order to determine the mechanism of bacterial tolerance to fluorine,Acidithiobacillus ferrooxidans ATCC 23270 was domesticated and studied under the conditions of different fluorine concentrations and pH values wit...In order to determine the mechanism of bacterial tolerance to fluorine,Acidithiobacillus ferrooxidans ATCC 23270 was domesticated and studied under the conditions of different fluorine concentrations and pH values with or without treatment by Proteinase K.The bacterial activities were observed through measuring the changes of solution potentials by platinum electrode with Ag/AgCl reference electrode and the intracellular fluorine was determined by-uorine ion-selective electrode.The results indicated that the tolerance of Acidithiobacillus ferrooxidans ATCC 23270 to fluorine could be obviously improved by domestication,HF was the effective form of fluorine to affect the bacterial activity,and pH increase or concentration change of ions of strong complex ability with fluorine ions in solution could result in false appearance of high fluorine-resistant strain.Some proteins located in cell wall or cell membrane were intimately relative with the bacterial fluorine tolerance.展开更多
This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial desig...This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.展开更多
Groundwater in contact with ore deposits may acquire a chemical composition that could be used as a guide for exploration. Eight well-water samples are collected from a known uraniummineralized area near Abu Zenima, w...Groundwater in contact with ore deposits may acquire a chemical composition that could be used as a guide for exploration. Eight well-water samples are collected from a known uraniummineralized area near Abu Zenima, west central Sinai to examine the applicability of using the hydrogeochemical technique in the search for uranium mineralization in similar arid areas. The analytical chemical data of the ground water is compared with ground radiometric measurements. The obtained results indicate that groundwater affected by uranium mineralization has a specific relativity of major anions expressed essentially as SO_4〉Cl〉HCO_3 and to a lesser extent as Cl〉SO_4〉HCO_3, associated as a rule with low magnesium content. This association constitutes a signature of uranium mineralization on the composition of groundwater in west central Sinai and could be used as an important exploration guide in the search for uranium deposits in similar areas. Anomalies in Ni, Fe, Zn and Cr and other pathfinder elements in groundwater can furnish geochemical guides to uranium ores. The immobile trace element anomalies, including Zn, Ni and Fe are strongly distributed near the orebody; whereas the relatively mobile trace elements, including Co, U, V and Cr, constitute the dispersion haloes away from the orebody. A new hydrogeochemical discrimination diagram is constructed to be used as a quick and cost effective exploration tool in the search for uranium occurrences in environmentally similar arid areas. Based on the obtained results, a new site for uranium occurrence, west of W. Baba, is delineated and recommended for future detailed geological and geochemical surveying.展开更多
This paper elaborates on the development of paste backfill using mill tailings generated during the processing of a uranium ore deposit hosted in dolomitic limestone. The tailings have been characterized in terms of t...This paper elaborates on the development of paste backfill using mill tailings generated during the processing of a uranium ore deposit hosted in dolomitic limestone. The tailings have been characterized in terms of the physical, chemical and mineralogical properties. Time-dependent rheological behaviors and geotechnical properties of cemented paste backfill(CPB) are also determined. The studies show that the mill tailing has the potential to form paste and the CPB has adequate strength to provide support to mine pillars, roofs, and walls.展开更多
Currently there have been formed industrial uranium deposits in Kyzylkum province that refer to three types of formations—exogenetic uranium formation in the sediments of Mesozoic-Cenozoic cover,endogenic molybdenum-...Currently there have been formed industrial uranium deposits in Kyzylkum province that refer to three types of formations—exogenetic uranium formation in the sediments of Mesozoic-Cenozoic cover,endogenic molybdenum-uranium formation and polygenic molybdenum-uranium-vanadium formation in carbon-siliceous shale formations ("black-shale"type).Carbon-siliceous shales are展开更多
Many theoretical results on sandstone-type uranium mineralization in northern China obtained by the uranium research team of the Tianjin Center of Geological Survey in recent years are presented.From the source sink s...Many theoretical results on sandstone-type uranium mineralization in northern China obtained by the uranium research team of the Tianjin Center of Geological Survey in recent years are presented.From the source sink system of uranium-producing basins,sedimentary environment of uranium-bearing rock series,ore-forming fluid information,evolution of tectonic events,basin formation and development,we redefine and classify uranium orebodies,redox zoning,and ore-controlling structural styles.We then systematically propose a theoretical system of sandstone-type uranium deposits in northern China.We conclude that sandstone-type uranium deposits in northern China are mainly found in sedimentary environments such as rivers,deltas,and alluvial fans in the Mesozoic and Cenozoic lowstand systems tract and in gray sandstone layers in the vertical redox zoning.The orebodies are controlled by the tectonic slope belt,which is in the shape of a strip on the plane,and spreads in a layer or plate on the section.Vertical(ups and downs)tectonic movement triggers large-scale phreatic flow in the basin,which is the real driving force for controlling the ore-forming fluid.The theoretical system of sandstone-type uranium deposits in northern China should be based on global tectonic movement and environmental changes and take into account factors such as basins as a unit to study mineralization background,ore concentration areas as objects to study mineralization,and the correlation between regional tectonic movement and metallogenic process as a breakthrough point to study tectonic events and metallogenic events.It should also be based on different basin types to establish metallogenic models.The innovative research results and ideas are summarized with the aim of promoting the continuous improvement of sandstone-type uranium mineralization theory in northern China.展开更多
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 macer...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.Differences in hydrodynamic intensity,redox condition,and microbial activity intensity between sedimentary paleoenvironment of CD and peat,show that CD is born in synsedimentary sandstone environment not in peat.Hence,it comprehensively draws conclusions that immature‘non-peatborn’CD is formed from the trunk,stem,branch,root fragments buried in sandstones,depositing in(micro)allochthonous positions by the influences of fluctuating water.The DOM from synsedimentary plant debris might play more roles in adsorption and complexation,and microorganisms may participate in uranium mineralization,which could provide certain guidance for uranium exploration and mining.展开更多
The U-Pb isotope system and uranium isotope composition(235U/238U and 234U/238U)were studied in a number of samples from the vertical section of the uranium ore body at the Vershinnoe sandstone-type deposit,Vitim uran...The U-Pb isotope system and uranium isotope composition(235U/238U and 234U/238U)were studied in a number of samples from the vertical section of the uranium ore body at the Vershinnoe sandstone-type deposit,Vitim uranium ore district,Russia.These parameters were determined to broadly vary.Deviations of the 234U/238U ratio from the equilibrium value indicate that the uranium ore was not completely conserved during the postore stage,and uranium was determined to continue migrating at the deposit.Comparison of the U-Pb isotope age value and 234U/238U isotope ratio provides an insight into the migrate direction of uranium in the ore body.The broad variations(137.377–137.772)in the 238U/235U ratio over the vertical section of the ore body can be explained by the different settings of the samples relative to the ore deposition front and changes in the redox conditions when this front shifted.The fact that theδ238U and K234/238 values are correlated indicates that the transfer of the 234U isotope into the aqueous phase may have been coupled with isotope fractionation in the 238U-235U system during the postformation uranium migration within the orebody.展开更多
A new method suitable for determining specific activity of 230Th in uranium ore samples is built. The method is characterized by adding the 230Th/ 232Th standard dilution agent with lower activity ratio (Its 230Th/ 23...A new method suitable for determining specific activity of 230Th in uranium ore samples is built. The method is characterized by adding the 230Th/ 232Th standard dilution agent with lower activity ratio (Its 230Th/ 232Th activity ratio and Th have been known) to the samples and using isotopic dilution analysis. The method can be applied to analyses of 230Th specific activity in various 230Th/ 232Th activity ratio samples. The precision can also be improved.展开更多
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 ...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.展开更多
Sandstone type deposits are the most common type of uranium deposits in the world.A large variety of sub-types have been defined,based either on the morphology of the deposits(e.g.,tabular,roll front,etc),or on the se...Sandstone type deposits are the most common type of uranium deposits in the world.A large variety of sub-types have been defined,based either on the morphology of the deposits(e.g.,tabular,roll front,etc),or on the sedimentological setting(e.g.,paleovalley,paleochannel,unconformity),or on tectonic or lithologic controls(e.g.,tectonolithologic,mafic dykes/sills),or still on a variety of others characteristics(phreatic oxidation type,interlayer permeable type,multi-element stratabound infiltrational,solution front limb deposit,humate type,etc.),reflecting the diversity of the characteristics of these deposits,but making it difficult to have a clear overview of these deposits.Moreover,uranium deposits occurring in the same sedimentological setting(e.g.,paleochannel),presenting similar morphologies(e.g.,tabular),may result from different genetic mechanisms and thus can be misleading for exploration strategies.The aim of the present paper is to propose a new view on sandstone-related uranium deposits combining both genetic and descriptive criteria.The dual view is indeed of primordial importance because all the critical characteristics of each deposit type,not limited to the morphology/geometry of the ore bodies and their relationships with depositional environments of the sandstone,have to be taken into account to propose a comprehensive classification of uranium deposits.In this respect,several key ore-forming processes,like the physical-chemical characteristics of the mineralizing fluid,have to be used to integrate genetic aspects in the classification.Although a succession of concentration steps,potentially temporally-disconnected,are involved in the genesis of some uranium mineralization,the classification here proposed will focus on the main mechanisms responsible for the formation and/or the location of ore deposits.The objective of this paper is also to propose a robust and widely usable terminology to define and categorize sandstone uranium deposits,considering the diversity of their origin and morphologies,and will be primarily based on the temperature of the mineralizing fluid considered as having played the critical role in the transportation of the uranium,starting from synsedimentary uranium deposits to those related to higher temperature fluids.展开更多
In recent years,the close relationship between uranium and Ti-Fe oxides in the sandstonetype uranium deposits has been extensively recognized.However,the altered characteristics of ilmenite and its relationship with u...In recent years,the close relationship between uranium and Ti-Fe oxides in the sandstonetype uranium deposits has been extensively recognized.However,the altered characteristics of ilmenite and its relationship with uranium enrichment still remain unclear.With this paper based on heavymineral sorting of uranium ore selected from the Tarangaole-Nalinggou deposit in the northeastern Ordos Basin,electron probe,backscattering image,energy spectrum and scanning electron microscopy were systematically performed.The ilmenite in the sandstone can be divided into four groups,including unaltered,weakly altered,moderately altered,and strongly altered ilmenite.The alteration of ilmenite in uranium ores is notably more intense than that of the surrounding rocks.In addition,weakly,moderately,and strongly altered ilmenite associated with uranium minerals in uranium ores demonstrate that the more intensity ilmenite altered,the closer its relationship with uranium minerals is.The ilmenite has likely been somewhat altered before mineralization,and the alteration intensifies by later exposure related to an oxygencontaining fluid.The alteration mechanism comprises a process of competitive diffusion between Fe^(2+)and O_(2)-ions.In the early stage,Fe ions was mainly diffused on the particle surface.Subsequently,diffusion of O ions into the particles began to be dominate.Most of the leached iron is stripped or carried away by fluid.In an alkaline and reductive environment,the remaining iron is reduced to form the surrounding pyrite,and TiO_(2)in a form of titanium sol recrystallizes(i.e.,anatase).Backscattering images show that uranium and altered ilmenite are close in space.Coffinite is often distributed along the edges of altered ilmenite as burrs in shape.Colloidal or knitted coffinite associated with anatase is formed in the voids of altered ilmenite.The chemical composition of altered ilmenite varies considerably from the core to edge,and the mineral assemblage sequence is from girdle with ilmenite,to leucosphenite,to anatase,and to coffinite.There is no brannerite that is symbiotic with altered ilmenite.It is considered to be a uranium-containing titanium mineral aggregate caused by the reduction and adsorption of uranium.As the altered product of ilmenite,TiO_(2)is an aggregation agent,increasing the concentration of uranium by adsorption.Together with Fe^(2+)and S_(2)-in secondary pyrite,this aggregate creates a uranium-rich environment in the microzone for the formation of coffinite.Therefore,the alteration of ilmenite plays a geochemical role in the processes of sedimentary,diagenesis and mineralization,in which Fe is removed,Ti is enriched,and U is adsorbed and reduced.展开更多
Compared to the sandstone-type uranium deposits in the Ordos Basin and the Songliao Basin,the Tamusu uranium deposit in the Bayingobi Basin formed in fault-depression transition region displays distinctive features.Fi...Compared to the sandstone-type uranium deposits in the Ordos Basin and the Songliao Basin,the Tamusu uranium deposit in the Bayingobi Basin formed in fault-depression transition region displays distinctive features.First,the uranium-bearing sandstones and their interlayer oxidation zone extend longitudinally no more than ten kilometers.Second,gravity flow sediments are more common in the uranium-bearing strata.Comprehensive facies analysis indicates that the Upper Member(orebearing horizon)of the Bayingobi Formation was largely deposited in fan deltas that prograded into lakes during period of relatively dry paleoclimate.Spatial distribution patterns of five facies associations along with two depositional environments(fan delta,lake)were reconstructed in this study.The results demonstrated that the depositional systems and their inner genetic facies played different roles in uranium reservoir sandstone,confining beds(isolated barrier beds)and reduction geologic bodies during uranium mineralization process.展开更多
In the continental basins of Northern China(NC),a series of energy resources commonly co-exist in the same basin.As the three typical superimposed basins of different genesis in the NC,the Junggar,Ordos,and Songliao b...In the continental basins of Northern China(NC),a series of energy resources commonly co-exist in the same basin.As the three typical superimposed basins of different genesis in the NC,the Junggar,Ordos,and Songliao basins were chosen as the research objects.The favorable uraniumbearing structures are generally shown as a basin-margin slope or transition belt of uplifts with the development of faults,which are conducive to a fluid circulation system.The Hercynian,Indosinian,and Yanshanian movements resulted in the development of uranium-rich intrusions which acted as the significant uranium sources.The main hydrocarbon source rocks are developed in the Carboniferous,Permian,Jurassic and Cretaceous.The mature stage of source rocks is concentrated in the Jurassic–Cretaceous,followed by the multi-stage expulsion events.Influenced by the India-Eurasian collision and the subduction of the Pacific Plate,the tectonic transformation in the Late Yanshanian and Himalayan periods significantly influenced the sandstone-type uranium mineralization.The hydrocarbon reservoirs are spatially consistent with sandstone-type uranium deposits,while the hydrocarbon expulsion events occur in sequence with sandstone-type uranium mineralization.In the periphery of the faults or the uplifts,both fluids met and formed uranium concentration.The regional tectonic movements motivate the migration of hydrocarbon fluids and uranium mineralization,especially the Himalayan movement.展开更多
The Zoujiashan uranium deposit in the Xiangshan ore field is the largest volcanic-related uranium deposit in China.Hematite-and fluorite-type ores are the predominant mineralization styles.Hematitization in the Xiangs...The Zoujiashan uranium deposit in the Xiangshan ore field is the largest volcanic-related uranium deposit in China.Hematite-and fluorite-type ores are the predominant mineralization styles.Hematitization in the Xiangshan ore field is closely associated with uranium mineralization,mainly occurring as hematitized rocks enclosing fluorite-type vein ores developed in pre-ore illitized porphyritic lava.Detailed petrographic and mass balance calculation studies were conducted to evaluate the mechanisms for uranium precipitation and mass transfer during hematitization.Petrographic observations suggest that in the hematitized rocks,orthoclase is more altered than plagioclase,and quartz dissolution is common,whereas in the illitized rocks,pyrite commonly occurs within the altered biotite grains,and chlorite grains are locally found.Mass balance calculations indicate that Na2O and U were gained,K2O,Ca O and Si O2were lost,whereas Fe2O3-t remained more or less constant during hematitization.These observations suggest that the hydrothermal fluids were Na-and U-rich and Ca-K-poor,and the Fe2+used for hematitization was locally derived,most likely from biotite,pyrite and chlorite in the host rocks.The Fe2+is inferred to have played the role of reductant to precipitate uranium,and calculation indicates that oxidation of Fe2+provided by host rocks is sufficient to form ores of economic significance.Consequently,the hematite-type ore is interpreted to be generated by the reaction between oxidized ore fluids and reduced components in host rocks.The development of calcite and pyrite in the fluorite ores suggests that perhaps mixing between the U-rich fluid and another fluid carrying reduced sulfur and carbon may have also contributed to uranium mineralization,in addition to temperature and pressure drop associated with the veining.展开更多
That more than 82 percent of proved sandstone-type uranium deposits coexist with proved oil-gas or coalfields in the world reflects the fact of coexistence and accumulation of multi-energy minerals including oil,gas,c...That more than 82 percent of proved sandstone-type uranium deposits coexist with proved oil-gas or coalfields in the world reflects the fact of coexistence and accumulation of multi-energy minerals including oil,gas,coal and uranium in the same basin.Especially,this phenomenon is most typical in the Central-east Asia energy basins.Across China,Mongolia and some central Asian countries,the giant Central-east Asia metallogenetic domain(CEAMD)stretches more than 6,000 km from Songliao Basin of China in the east to the Caspian Sea in the west.The multi-energy minerals distribution characteristics of the domain include:their spatial distribution is complicated and ordered;the ore-bearing horizon relates closely to the geographical region;the accumulation/mineralization and localization time is the same or close;the occurrence setting and accumulation/mineralization have close correlation;and they have rich provenance for all the minerals.All of these imply that they have close relations between each other under a unified geodynamic background.The exogenetic uranium mineralization process in CEAMD can be divided into five phases using time limits of 100 Ma,(50±2)Ma,20±(2―4)Ma,8―5 Ma.The major mineralization periods and their differences in each primary uranium-bearing basin are identical to the oil-gas accumulation and localization periods and phases in the same basin,and are also in response to regional tectonics and controlled in general by the regional geodynamic environment.For industrial application and commercial exploitation,it is suggested that an important period for coexistence,accumulation and localization of oil,gas,coal and uranium and their interaction mainly occur in the late/last and post basin evolution.Through generalized analysis and comparison of accumulation/mineralization environment of the energy basins in CEAMD,the authors propose that the relatively stable regional tectonic background and moderate(weaker)structural deformation probably are necessary for formation,coexistence and preservation of large and medium-scaled sandstone-type uranium ore deposits,oil-gas fields and coalfields,while basins in favor of coexistence and accumulation are those intracratonal,intermediary massif basins and corresponding reformed basins.展开更多
基金the Foundation of State Key Laboratory of Nuclear Resources and Environment(Grant Nos.NRE2021-01,2022NRE34)the National Natural Science Foundation of China(Grant No.42162013)+1 种基金the Third Xinjiang Scientific Expedition Program(Grant No.2022xjkk1301)the Fund of National Key Laboratory of Science and Technology on Remote Sensing Information and imagery Analysis,Beijing Research Institute of Uranium Geology(Grant No.6142A01210405).
文摘Xiazhuang uranium ore field,located in the southern part of the Nanling Metallogenic Belt,is considered one of the largest granite-related U regions in South China.In this paper,we contribute new apatite fission track data and thermal history modeling to constrain the exhumation history and evaluate preservation potential of the Xiazhuang Uranium ore field.Nine Triassic outcrop granite samples collected from different locations of Xiazhuang Uranium ore field yield AFT ages ranging from 43 to 24 Ma with similar mean confined fission track lengths ranging from 11.8±2.0 to 12.9±1.9μm and Dpar values between 1.01 and 1.51μm.The robustness time-temperature reconstructions of samples from the hanging wall of Huangpi fault show that the Xiazhuang Uranium ore field experienced a time of monotonous and slow cooling starting from middle Paleocene to middle Miocene(~60-10 Ma),followed by relatively rapid exhumation in the late Miocene(~10-5 Ma)and nearly thermal stability in the Pliocene-Quaternary(~5-0 Ma).The amount of exhumation after U mineralization since the Middle Paleogene was estimated as~4.3±1.8 km according to the integrated thermal history model.Previous studies indicate that the ore-forming ages of U deposits in the Xiazhuang ore field are mainly before Middle Paleocene and the mineralization depths are more than 4.4±1.2 km.Therefore,the exhumation history since middle Paleocene plays important roles in the preservation of the Xiazhuang Uranium ore field.
基金supported by the Science and Technology Research Project of China Nuclear Geology(No.2110400024)Uranium Geological Exploration Fund Project of China National Nuclear Corporation(No.J2012-03)+1 种基金Uranium Mine Exploration Project of Hunan Nuclear Geology(No.DK30620170512)Scientific Research Program of Hunan Nuclear Geology(No.KYQ-306-01)。
文摘The Sanjiu uranium ore field,located in the central of Zhuguangshan granitic batholith,is a newly discovered granite-related uranium ore field in South China.The main sulfide in the ore field is pyrite,which is closely related to uranium mineralization.The textures major and trace elements,S-He-Ar isotopes compositions of pyrites in ores of different grade were observed and/or analyzed by optical microscope,scanning electron microscope,electron microprobe,laser ablation inductively coupled plasma mass spectrometry,and noble gas mass spectrometer(Helix-SFT).It is observed that these U-related pyrites are generally euhedral-subhedral with dissolution textures,anhedral variety with colloform texture veinlet and fine particles,and the color of the associated minerals is mostly dark hue,such as purple-black fluorite dark-red hematite,and dark-green chlorite,etc.The analytical results show that the average compositions of major elements in pyrite are FeS1.944.Pyrites are characterized by S-deficiency,low content of Co and Th,and Co/Ni>1which indicate that these ores are of low-temperature hydrothermal origin.We found that the higher the grade of ore,the more deficient in S,the more obvious negative δ^34S,and the higher REE content(close to U-rich granitic pluton)of pyrite.The S-He-Ar isotopic compositions of various varieties of pyrites indicate that the ore-forming fluids mainly come from crust-derived fluids and mixed with mantle-derived fluids.
文摘In 2006, SOMAIR decided to increase the uranium production by 50% using heap leaching for the treatment of low grade ores. These ores, which come from different lodes with various properties, have been studied in four steps: ( 1 ) Lab tests: to compare the ores (characterization, acid consumptions, recovery...); (2) Column tests on an average sample: to define significant parameters for a feasibility study; (3) Column tests on specific samples: to optimize recovery for each ore and identify problems of percolation due to the clays; (4) Pilot tests in large boxes (stalls): to validate process parameters. Uranium production by heap leaching started in July 2009.
文摘This study aims to assess the behavior of the release of Unat (i.e. uranium isotopes in natural relative abundance) from the release of water treated by the Ore Treatment Unit (UTM) in Caldas, state of Minas Gerais, Brazil, during the years 1999 to 2009. During this period, the unit showed no industrial activity, except between 2004 and 2005, when UTM operated 400 tons of monazite in a process to obtain rare earths. Unat was analyzed by spectrophotometry once per week in the effluent waters at sampling point 014. Two fractions were considered for analysis: the soluble one (that passes through a 0.45 μm filter) and the particulate one (retained on a 0.45 μm filter). Statistical analyses were performed: the “Z” test and Pearson’s r2 correlation index. The values for the soluble fraction were consistently lower than those of the particulate fraction and no statistically significant correlation was observed between the soluble and particulate fractions. However, the particulate and the total fractions (the sum of soluble and particulate) strongly correlated.
基金Project(2010CB630903) supported by the National Basic Research Program of China
文摘In order to determine the mechanism of bacterial tolerance to fluorine,Acidithiobacillus ferrooxidans ATCC 23270 was domesticated and studied under the conditions of different fluorine concentrations and pH values with or without treatment by Proteinase K.The bacterial activities were observed through measuring the changes of solution potentials by platinum electrode with Ag/AgCl reference electrode and the intracellular fluorine was determined by-uorine ion-selective electrode.The results indicated that the tolerance of Acidithiobacillus ferrooxidans ATCC 23270 to fluorine could be obviously improved by domestication,HF was the effective form of fluorine to affect the bacterial activity,and pH increase or concentration change of ions of strong complex ability with fluorine ions in solution could result in false appearance of high fluorine-resistant strain.Some proteins located in cell wall or cell membrane were intimately relative with the bacterial fluorine tolerance.
基金the Tarbiat Modares University & Nuclear Science and Technology Research Institute for their financial support
文摘This research aimed to enhance the column bioleaching recovery of uranium ore by Acidithiobacillus ferrooxidans.Seven factors were examined for their significance on bioleaching using a Plackett-Burman factorial design.Four significant variables([Fe2+]initial,pH,aeration rate and inoculation percent)were selected for the optimization studies.The effect of these variables on uranium bioleaching was studied using a central composite design(CCD).The optimal values of the variables for the maximum uranium bioleaching recovery(90.27±0.98)%were as follows:[Fe2+]initial=2.89g/L,aeration rate420mL/min,pH1.45and inoculation6%(v/v).[Fe2+]initial was found to be the most effective parameter.The maximum uranium recovery from the predicted models was92.01%.This value was in agreement with the actual experimental value.The analysis of bioleaching residue of uranium ore under optimum conditions confirmed the formation of K-jarosite on the surface of minerals.By using optimal conditions,uranium bioleaching recovery is increased at column and jarosite precipitation is minimized.The kinetic model showed that uranium recovery has a direct relation with ferric ion concentration.
文摘Groundwater in contact with ore deposits may acquire a chemical composition that could be used as a guide for exploration. Eight well-water samples are collected from a known uraniummineralized area near Abu Zenima, west central Sinai to examine the applicability of using the hydrogeochemical technique in the search for uranium mineralization in similar arid areas. The analytical chemical data of the ground water is compared with ground radiometric measurements. The obtained results indicate that groundwater affected by uranium mineralization has a specific relativity of major anions expressed essentially as SO_4〉Cl〉HCO_3 and to a lesser extent as Cl〉SO_4〉HCO_3, associated as a rule with low magnesium content. This association constitutes a signature of uranium mineralization on the composition of groundwater in west central Sinai and could be used as an important exploration guide in the search for uranium deposits in similar areas. Anomalies in Ni, Fe, Zn and Cr and other pathfinder elements in groundwater can furnish geochemical guides to uranium ores. The immobile trace element anomalies, including Zn, Ni and Fe are strongly distributed near the orebody; whereas the relatively mobile trace elements, including Co, U, V and Cr, constitute the dispersion haloes away from the orebody. A new hydrogeochemical discrimination diagram is constructed to be used as a quick and cost effective exploration tool in the search for uranium occurrences in environmentally similar arid areas. Based on the obtained results, a new site for uranium occurrence, west of W. Baba, is delineated and recommended for future detailed geological and geochemical surveying.
基金the Department of Atomic Energy (DAE),Government of India,for providing financial assistance (BARC/IFB/IITKHARAGPUR/295, Dt.18-03-2013) during this research work
文摘This paper elaborates on the development of paste backfill using mill tailings generated during the processing of a uranium ore deposit hosted in dolomitic limestone. The tailings have been characterized in terms of the physical, chemical and mineralogical properties. Time-dependent rheological behaviors and geotechnical properties of cemented paste backfill(CPB) are also determined. The studies show that the mill tailing has the potential to form paste and the CPB has adequate strength to provide support to mine pillars, roofs, and walls.
文摘Currently there have been formed industrial uranium deposits in Kyzylkum province that refer to three types of formations—exogenetic uranium formation in the sediments of Mesozoic-Cenozoic cover,endogenic molybdenum-uranium formation and polygenic molybdenum-uranium-vanadium formation in carbon-siliceous shale formations ("black-shale"type).Carbon-siliceous shales are
基金The“Northern Sandstone-type Uranium Deposits Investigation Project”(Project 0108)of the China Geological Survey has led to the discovery of many new sandstone-type uranium depositsThe National Basic Research Program(973 Program)(No.2015CB453000)+1 种基金the National Key R&D Program of China(No.2018YFC0604200)both from the Ministry of Science and Technology of the People’s Republic of China have led to innovations in many theoretical understandings of sandstone-type uranium depositsUnder the International Geoscience Programme(No.IGCP-675),a comparative study of sandstone-type uranium deposits between China and the rest of the world has been conducted。
文摘Many theoretical results on sandstone-type uranium mineralization in northern China obtained by the uranium research team of the Tianjin Center of Geological Survey in recent years are presented.From the source sink system of uranium-producing basins,sedimentary environment of uranium-bearing rock series,ore-forming fluid information,evolution of tectonic events,basin formation and development,we redefine and classify uranium orebodies,redox zoning,and ore-controlling structural styles.We then systematically propose a theoretical system of sandstone-type uranium deposits in northern China.We conclude that sandstone-type uranium deposits in northern China are mainly found in sedimentary environments such as rivers,deltas,and alluvial fans in the Mesozoic and Cenozoic lowstand systems tract and in gray sandstone layers in the vertical redox zoning.The orebodies are controlled by the tectonic slope belt,which is in the shape of a strip on the plane,and spreads in a layer or plate on the section.Vertical(ups and downs)tectonic movement triggers large-scale phreatic flow in the basin,which is the real driving force for controlling the ore-forming fluid.The theoretical system of sandstone-type uranium deposits in northern China should be based on global tectonic movement and environmental changes and take into account factors such as basins as a unit to study mineralization background,ore concentration areas as objects to study mineralization,and the correlation between regional tectonic movement and metallogenic process as a breakthrough point to study tectonic events and metallogenic events.It should also be based on different basin types to establish metallogenic models.The innovative research results and ideas are summarized with the aim of promoting the continuous improvement of sandstone-type uranium mineralization theory in northern China.
基金supported by the fellowship of China postdoctoral science foundation (No.2021M703001)the National Natural Science Foundation of China (No.42172128)+4 种基金the fundamental research funds for the Central Universities from China University of Geosciences (Wuhan)(No.G1323521101)the National Key Research and Development Program of China (No.2018YFC0604200)the International Geoscience Programme,IGCP 675:Supergene Fluid Ore-forming Process of Sandstone-type Uranium Depositsthe open fund of Key Laboratory of Tectonics and Petroleum Resources(China University of Geosciences),the Ministry of Education(No.TPR-2019-08)the Fund of Outstanding Talents in Discipline of China University of Geosciences (Wuhan)(No.102-162301192664)
文摘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.Differences in hydrodynamic intensity,redox condition,and microbial activity intensity between sedimentary paleoenvironment of CD and peat,show that CD is born in synsedimentary sandstone environment not in peat.Hence,it comprehensively draws conclusions that immature‘non-peatborn’CD is formed from the trunk,stem,branch,root fragments buried in sandstones,depositing in(micro)allochthonous positions by the influences of fluctuating water.The DOM from synsedimentary plant debris might play more roles in adsorption and complexation,and microorganisms may participate in uranium mineralization,which could provide certain guidance for uranium exploration and mining.
文摘The U-Pb isotope system and uranium isotope composition(235U/238U and 234U/238U)were studied in a number of samples from the vertical section of the uranium ore body at the Vershinnoe sandstone-type deposit,Vitim uranium ore district,Russia.These parameters were determined to broadly vary.Deviations of the 234U/238U ratio from the equilibrium value indicate that the uranium ore was not completely conserved during the postore stage,and uranium was determined to continue migrating at the deposit.Comparison of the U-Pb isotope age value and 234U/238U isotope ratio provides an insight into the migrate direction of uranium in the ore body.The broad variations(137.377–137.772)in the 238U/235U ratio over the vertical section of the ore body can be explained by the different settings of the samples relative to the ore deposition front and changes in the redox conditions when this front shifted.The fact that theδ238U and K234/238 values are correlated indicates that the transfer of the 234U isotope into the aqueous phase may have been coupled with isotope fractionation in the 238U-235U system during the postformation uranium migration within the orebody.
文摘A new method suitable for determining specific activity of 230Th in uranium ore samples is built. The method is characterized by adding the 230Th/ 232Th standard dilution agent with lower activity ratio (Its 230Th/ 232Th activity ratio and Th have been known) to the samples and using isotopic dilution analysis. The method can be applied to analyses of 230Th specific activity in various 230Th/ 232Th activity ratio samples. The precision can also be improved.
基金supported by the National Key Research and Development Program of China (No.2018YFC0604202)the National Science Fund Project (No.42172128)the International Geoscience Programme (No.IGCP-675)
文摘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.
基金financial support and providing access to their properties.Patrice Bruneton is warmly thanked for a thorought revision of the manuscript.This paper is a contribution to the IGCP project 675“Comparative analysis of mineralization of Sandstone-type U deposits”。
文摘Sandstone type deposits are the most common type of uranium deposits in the world.A large variety of sub-types have been defined,based either on the morphology of the deposits(e.g.,tabular,roll front,etc),or on the sedimentological setting(e.g.,paleovalley,paleochannel,unconformity),or on tectonic or lithologic controls(e.g.,tectonolithologic,mafic dykes/sills),or still on a variety of others characteristics(phreatic oxidation type,interlayer permeable type,multi-element stratabound infiltrational,solution front limb deposit,humate type,etc.),reflecting the diversity of the characteristics of these deposits,but making it difficult to have a clear overview of these deposits.Moreover,uranium deposits occurring in the same sedimentological setting(e.g.,paleochannel),presenting similar morphologies(e.g.,tabular),may result from different genetic mechanisms and thus can be misleading for exploration strategies.The aim of the present paper is to propose a new view on sandstone-related uranium deposits combining both genetic and descriptive criteria.The dual view is indeed of primordial importance because all the critical characteristics of each deposit type,not limited to the morphology/geometry of the ore bodies and their relationships with depositional environments of the sandstone,have to be taken into account to propose a comprehensive classification of uranium deposits.In this respect,several key ore-forming processes,like the physical-chemical characteristics of the mineralizing fluid,have to be used to integrate genetic aspects in the classification.Although a succession of concentration steps,potentially temporally-disconnected,are involved in the genesis of some uranium mineralization,the classification here proposed will focus on the main mechanisms responsible for the formation and/or the location of ore deposits.The objective of this paper is also to propose a robust and widely usable terminology to define and categorize sandstone uranium deposits,considering the diversity of their origin and morphologies,and will be primarily based on the temperature of the mineralizing fluid considered as having played the critical role in the transportation of the uranium,starting from synsedimentary uranium deposits to those related to higher temperature fluids.
基金financially supported by projects under the National Key Research and Development Program of China(No.2018YFC0604200)the Open Fund Project of State Key Laboratory of Nuclear Resources and Environment (No.2020NRE10)+3 种基金the National Key Infrastructure Development Plan (No.2015CB453006)the China Geological Survey (Nos.DD20190119,DD20221678)the International Geoscience Programme (No.IGCP-675)the National Nature Science Foundation of China (No.92162212)
文摘In recent years,the close relationship between uranium and Ti-Fe oxides in the sandstonetype uranium deposits has been extensively recognized.However,the altered characteristics of ilmenite and its relationship with uranium enrichment still remain unclear.With this paper based on heavymineral sorting of uranium ore selected from the Tarangaole-Nalinggou deposit in the northeastern Ordos Basin,electron probe,backscattering image,energy spectrum and scanning electron microscopy were systematically performed.The ilmenite in the sandstone can be divided into four groups,including unaltered,weakly altered,moderately altered,and strongly altered ilmenite.The alteration of ilmenite in uranium ores is notably more intense than that of the surrounding rocks.In addition,weakly,moderately,and strongly altered ilmenite associated with uranium minerals in uranium ores demonstrate that the more intensity ilmenite altered,the closer its relationship with uranium minerals is.The ilmenite has likely been somewhat altered before mineralization,and the alteration intensifies by later exposure related to an oxygencontaining fluid.The alteration mechanism comprises a process of competitive diffusion between Fe^(2+)and O_(2)-ions.In the early stage,Fe ions was mainly diffused on the particle surface.Subsequently,diffusion of O ions into the particles began to be dominate.Most of the leached iron is stripped or carried away by fluid.In an alkaline and reductive environment,the remaining iron is reduced to form the surrounding pyrite,and TiO_(2)in a form of titanium sol recrystallizes(i.e.,anatase).Backscattering images show that uranium and altered ilmenite are close in space.Coffinite is often distributed along the edges of altered ilmenite as burrs in shape.Colloidal or knitted coffinite associated with anatase is formed in the voids of altered ilmenite.The chemical composition of altered ilmenite varies considerably from the core to edge,and the mineral assemblage sequence is from girdle with ilmenite,to leucosphenite,to anatase,and to coffinite.There is no brannerite that is symbiotic with altered ilmenite.It is considered to be a uranium-containing titanium mineral aggregate caused by the reduction and adsorption of uranium.As the altered product of ilmenite,TiO_(2)is an aggregation agent,increasing the concentration of uranium by adsorption.Together with Fe^(2+)and S_(2)-in secondary pyrite,this aggregate creates a uranium-rich environment in the microzone for the formation of coffinite.Therefore,the alteration of ilmenite plays a geochemical role in the processes of sedimentary,diagenesis and mineralization,in which Fe is removed,Ti is enriched,and U is adsorbed and reduced.
基金financially supported by the National Natural Sciences Fund (No.42172128)the National Key Research and Development Program of China (No.2018YFC0604200)the International Geoscience Programme (IGCP-675)
文摘Compared to the sandstone-type uranium deposits in the Ordos Basin and the Songliao Basin,the Tamusu uranium deposit in the Bayingobi Basin formed in fault-depression transition region displays distinctive features.First,the uranium-bearing sandstones and their interlayer oxidation zone extend longitudinally no more than ten kilometers.Second,gravity flow sediments are more common in the uranium-bearing strata.Comprehensive facies analysis indicates that the Upper Member(orebearing horizon)of the Bayingobi Formation was largely deposited in fan deltas that prograded into lakes during period of relatively dry paleoclimate.Spatial distribution patterns of five facies associations along with two depositional environments(fan delta,lake)were reconstructed in this study.The results demonstrated that the depositional systems and their inner genetic facies played different roles in uranium reservoir sandstone,confining beds(isolated barrier beds)and reduction geologic bodies during uranium mineralization process.
基金jointly supported by the National Key Research and Development Program of China (No.2018YFC0604200)the National Science Foundation of China (Nos.92162212,41502195)+2 种基金the International Geoscience Programme (No.GCP-675)the Open Fund Project of State Key Laboratory of Nuclear Resources and Environment (No.2020NRE10)the Geological Survey Project of China Geological Survey (Nos.DD20190121,DD20190119,DD20211191,and DD20221678)
文摘In the continental basins of Northern China(NC),a series of energy resources commonly co-exist in the same basin.As the three typical superimposed basins of different genesis in the NC,the Junggar,Ordos,and Songliao basins were chosen as the research objects.The favorable uraniumbearing structures are generally shown as a basin-margin slope or transition belt of uplifts with the development of faults,which are conducive to a fluid circulation system.The Hercynian,Indosinian,and Yanshanian movements resulted in the development of uranium-rich intrusions which acted as the significant uranium sources.The main hydrocarbon source rocks are developed in the Carboniferous,Permian,Jurassic and Cretaceous.The mature stage of source rocks is concentrated in the Jurassic–Cretaceous,followed by the multi-stage expulsion events.Influenced by the India-Eurasian collision and the subduction of the Pacific Plate,the tectonic transformation in the Late Yanshanian and Himalayan periods significantly influenced the sandstone-type uranium mineralization.The hydrocarbon reservoirs are spatially consistent with sandstone-type uranium deposits,while the hydrocarbon expulsion events occur in sequence with sandstone-type uranium mineralization.In the periphery of the faults or the uplifts,both fluids met and formed uranium concentration.The regional tectonic movements motivate the migration of hydrocarbon fluids and uranium mineralization,especially the Himalayan movement.
基金co-founded by the National Natural Science Foundation of China(Nos.42002090,41930428)the National Key Research and Development Program of China(No.2018YFC0604200)+5 种基金the Project of China Geological Survey(No.DD20190119)the Open Research Fund Program of State Key Laboratory of Nuclear Resources and Environment,East China University of Technology(No.NRE1915)the Open Research Fund Program of Jiangxi Engineering Laboratory on Radioactive Geoscience and Big Data Technology(No.JELRGBDT202006)the International Geoscience Programme(No.IGCP-675)the Jiangxi province graduate student innovation special fund project(YC2019-S271)the East China University of Technology graduate student innovation special fund project(No.DHYC-202001)。
文摘The Zoujiashan uranium deposit in the Xiangshan ore field is the largest volcanic-related uranium deposit in China.Hematite-and fluorite-type ores are the predominant mineralization styles.Hematitization in the Xiangshan ore field is closely associated with uranium mineralization,mainly occurring as hematitized rocks enclosing fluorite-type vein ores developed in pre-ore illitized porphyritic lava.Detailed petrographic and mass balance calculation studies were conducted to evaluate the mechanisms for uranium precipitation and mass transfer during hematitization.Petrographic observations suggest that in the hematitized rocks,orthoclase is more altered than plagioclase,and quartz dissolution is common,whereas in the illitized rocks,pyrite commonly occurs within the altered biotite grains,and chlorite grains are locally found.Mass balance calculations indicate that Na2O and U were gained,K2O,Ca O and Si O2were lost,whereas Fe2O3-t remained more or less constant during hematitization.These observations suggest that the hydrothermal fluids were Na-and U-rich and Ca-K-poor,and the Fe2+used for hematitization was locally derived,most likely from biotite,pyrite and chlorite in the host rocks.The Fe2+is inferred to have played the role of reductant to precipitate uranium,and calculation indicates that oxidation of Fe2+provided by host rocks is sufficient to form ores of economic significance.Consequently,the hematite-type ore is interpreted to be generated by the reaction between oxidized ore fluids and reduced components in host rocks.The development of calcite and pyrite in the fluorite ores suggests that perhaps mixing between the U-rich fluid and another fluid carrying reduced sulfur and carbon may have also contributed to uranium mineralization,in addition to temperature and pressure drop associated with the veining.
基金Jointly supported by the National Important Basic Research Program of China(Grant No.2003CB214607)Program for Changjiang Scholars and Innovative Research Team in University(Grant No.IRT0559)the National Natural Science Foundation of China(Grant No.40372096)
文摘That more than 82 percent of proved sandstone-type uranium deposits coexist with proved oil-gas or coalfields in the world reflects the fact of coexistence and accumulation of multi-energy minerals including oil,gas,coal and uranium in the same basin.Especially,this phenomenon is most typical in the Central-east Asia energy basins.Across China,Mongolia and some central Asian countries,the giant Central-east Asia metallogenetic domain(CEAMD)stretches more than 6,000 km from Songliao Basin of China in the east to the Caspian Sea in the west.The multi-energy minerals distribution characteristics of the domain include:their spatial distribution is complicated and ordered;the ore-bearing horizon relates closely to the geographical region;the accumulation/mineralization and localization time is the same or close;the occurrence setting and accumulation/mineralization have close correlation;and they have rich provenance for all the minerals.All of these imply that they have close relations between each other under a unified geodynamic background.The exogenetic uranium mineralization process in CEAMD can be divided into five phases using time limits of 100 Ma,(50±2)Ma,20±(2―4)Ma,8―5 Ma.The major mineralization periods and their differences in each primary uranium-bearing basin are identical to the oil-gas accumulation and localization periods and phases in the same basin,and are also in response to regional tectonics and controlled in general by the regional geodynamic environment.For industrial application and commercial exploitation,it is suggested that an important period for coexistence,accumulation and localization of oil,gas,coal and uranium and their interaction mainly occur in the late/last and post basin evolution.Through generalized analysis and comparison of accumulation/mineralization environment of the energy basins in CEAMD,the authors propose that the relatively stable regional tectonic background and moderate(weaker)structural deformation probably are necessary for formation,coexistence and preservation of large and medium-scaled sandstone-type uranium ore deposits,oil-gas fields and coalfields,while basins in favor of coexistence and accumulation are those intracratonal,intermediary massif basins and corresponding reformed basins.