蚀源区地质体铀浸出率与砂岩铀矿成矿关系

通过吐哈盆地南缘觉罗塔格山系和准噶尔盆地周缘（不包括准盆南缘北天山山脉）不同岩石浸出试验发现，同属中晚古生代的侵入岩、火山岩及变质岩，在相同条件下其铀浸出率有明显差异，即吐哈盆地南缘各类岩石的总浸出率在14.30%，而准噶尔盆地周缘（不包括准盆南缘北天山山脉）岩石的总浸出率仅为1.81%，这也许正是吐哈盆地南缘形成万吨级砂岩铀矿，而准盆北部（顶山地区）砂岩铀矿成矿前景欠佳，目前只有个别工业铀矿孔及部分矿化孔，而不具工业意义的原因之一。     

砂岩铀矿成矿过程中有机质作用的实验研究--以吐鲁番-哈密盆地十红滩铀矿床为例

本文利用采自吐鲁番-哈密盆地西南部的样品,有针对性地做了一系列有机质抽提及分离实验,即①利用氯仿抽提岩石中有机质实验;②利用CS2-NmP(二硫化碳-N-甲基-2吡咯烷酮)抽提岩石中有机质实验;③腐殖质提取及分离实验。以上有机质抽提物及分离物分别做铀含量测试。通过实验发现,按以上实验顺序．岩石有机质提取物或分离物中铀含量依次有不同程度的提高,其中以腐殖质中分离出的黄腐酸(Fulvic acids)中铀含量最高,说明在吐哈盆地西南部砂岩铀矿的形成过程中有机质(主要是腐殖质和沥青质)的吸附作用起到部分作用．起最主要作用的是黄腐酸,而且与铀酰离子是以络合(或螯合)形式进行迁移。通过实验和分析,作者认为腐殖质(Humic substances)的络合作用和吸附作用在铀的迁移过程中是紧密相联的,而不是互相孤立的两种作用。在铀的迁移和沉淀富集过程中,黄腐酸(Fulvic acids)和腐殖酸(Humic acids)分别起到不同作用。     

天山造山带内中新生代盆地构造演化与砂岩型铀矿成矿的关系——以伊犁盆地、吐哈盆地为例

天山造山带内分布着众多的中新生代盆地,其中伊犁盆地、吐鲁番-哈密盆地(吐哈盆地)是重要的产铀盆地,已成为我国地浸砂岩型铀矿的重要基地.本文详细研究了伊犁盆地、吐哈盆地的构造演化、动力学机制及其与砂岩型铀成矿的关系.     

吐哈盆地周缘晚古生代火山岩地质地化特征及构造意义

吐哈盆地周缘晚古生代火山岩地质地化特征及构造意义倪志耀，卫管一，周济元（成都理工学院，成都６１００５９）（南京地质矿产研究所，南京２１００１６）关键词吐哈盆地、晚古生代、火山岩、地球化学特征、构造意义１地质特征吐哈盆地周缘晚古生代火山岩分布北至乌鲁木...     

吐哈盆地铀成矿远景区构造型式

吐哈盆地是我国重要的地浸砂岩型铀矿成矿盆地。经过对吐哈盆地的综合地质调查、钻探评价和资料分析研究，预测出西南缘艾丁湖斜坡带、大南湖、沙尔湖、三道岭地区和塔克泉构造带为地浸砂岩型铀成矿远景区。铀成矿远景区由于构造作用的相对特殊性和差异性，可划分出断-超褶曲式、断-隆式、断-阶式、斜-断式（单斜式）4种构造型式，这4种构造型式对铀成矿作用过程产生不同制约。综合分析认为艾丁湖斜坡带、大南湖地区地浸砂岩型铀矿成矿构造条件最好：三道岭、沙尔湖虽具备局部稳定构造斜坡环境，但受构造影响，潜力有限。     

吐哈盆地中侏罗统西山窑组砂岩主量元素特征及指示意义

结合前人研究资料及中东部西山窑组砂岩物质组成特征和形成构造背景条件,分析吐哈盆地整体铀矿成矿条件。通过地球化学方法对比吐哈盆地东西部中侏罗统西山窑组砂岩主量元素特征,发现吐哈盆地东西部西山窑组砂岩主量元素组成上具较高的相似性,与PASS相比表现出高SiO2,其余组分较低特征。吐哈盆地东西部砂岩源岩风化程度具很高的一致性,西山窑组砂岩源岩均来自中酸性岩石,西山窑组砂岩形成于稳定的构造背景环境。对比发现,吐哈盆地东西部砂岩主量元素成分及形成构造背景具很高的一致性,结合前人对十红滩铀矿床的研究,认为吐哈盆地大面积铀成矿具很大潜力。     

吐哈盆地西南缘层间氧化带型铀矿的地质特征及成矿条件分析

本文详实介绍了吐哈盆地地质特征、砂体特征、层间氧化带特征、铀矿化特征和铀成矿条件,指出了西山窑组一、二、三岩性段为主要找矿层位,认为吐哈盆地具有良好的成矿前景。     

吐哈盆地苏巴什地区铀矿化特征及成矿规律研究

苏巴什铀矿点位于吐哈盆地艾丁湖斜坡带最西端,是近年在吐哈盆地新发现的铀矿点。通过岩心观察、化学分析、薄片、电子探针和扫描电镜等测试手段,对铀矿地质特征、物源、铀源、铀矿物赋存状态、氧化蚀变、粘土矿物等进行研究,结合前人成果,系统总结苏巴什铀成矿规律。研究表明,铀矿化产于中侏罗统西山窑组,主要呈板状,矿石矿物以铀的钛氧化物为主,铀石次之。铀矿化与层间氧化蚀变、有机质、粘土矿物密切相关,主要赋存于层间氧化蚀变带翼部灰色砂岩中。矿石中粘土矿物以伊利石为主,富含有机质,侏罗纪晚期到渐新世末期,构造活动引发富氧含铀流体渗入,形成完整的“补-径-排”流体成矿系统,最终导致铀成矿作用发生。分析苏巴什铀成矿规律,建立成矿模式,可为吐哈盆地及同类地区铀矿勘查和研究提供指导作用。     

新疆觉罗塔格山与吐哈盆地的构造接触关系

吐哈盆地南北两侧与盆地紧密相接的两座山脉分别是觉罗塔格山和北天山。许多研究者对北天山以及山脉与盆地北界的构造关系做了大量研究，并发表了相当多的论文和研究报告。但是针对觉罗塔格山与吐哈盆地构造关系的研究尚未见报导。本文通过野外地质调查结合地震剖面研究认识到： 1.觉罗塔格山从板块构造归属上应与北天山一样同属于东天山造山带，它们是塔里木板块的一部分； 2.觉罗塔格山与吐哈盆地的构造交接形式在不同地段表现不同，可以划分为三种构造类型： 1）托克逊冲断带型； 2）鄯善伸展构造型； 3）哈密和缓褶皱型； 3.觉罗塔格山、北天山与吐哈盆地所形成的盆地─山脉构造景观是新生代以来产生的。     

浅谈铀、煤矿产资源综合勘查及评价——以吐哈盆地为例

从铀、煤矿产资源的市场需求和利用前景，在空间上的依存性和成因上的相关性3个方面，分析了铀、煤矿产资源综合勘查开发的合理性和可行性。并结合吐哈盆地西南缘铀资源勘查评价对铀、煤矿资源量的估算和价值分析，指出铀、煤资源综合勘查开发具有显著的经济效益。     

铀有机地球化学研究进展

与铀矿有密切关系的有机质主要是腐殖酸（HAs)、富里酸（FAs)、微生物及细菌。腐殖酸与铀酰存在着强烈的吸附、络合及还原作用关系。微生物和细菌在铀矿形成过程中也起到一定的作用。在研究手段上包括试验、计算、热解分析、X－线分析、裂变径迹分析、电子探针、红外光谱、紫外光谱、荧光光谱、顺磁共振、色谱质谱联用等方法。     

铀有机地球化学研究进展

与铀矿有密切关系的有机质主要是腐殖酸(HAs)、富里酸(FAs)、微生物及细菌.腐殖酸与铀酰存在着强烈的吸附、络合及还原作用关系.微生物和细菌在铀矿形成过程中也起到很微妙的作用.在研究手段上包括试验、计算、热解分析、X射线分析、裂变径迹分析、电子探针、红外光谱、紫外光谱、荧光光谱、顺磁共振、色谱质谱联用等方法.     

Differences in properties and Cm(III) complexation behavior of isolated humic and fulvic acid derived from Opalinus clay and Callovo-Oxfordian argillite

Fulvic acids from deep clay formations have been isolated by the International Humic Substances Society (IHSS) standard protocol and analyzed. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy reveals, that the basic structural features relating to the origin of the clay organic matter (i.e., terrestrial or marine) are preserved even after the around 150 Ma since deposition (Jurassic sediment). Analysis by asymmetrical flow field flow fractionation (AFFFF) shows the size distribution peak found for typical fulvic acids. In addition, a second larger size peak is found for the fulvic acids influenced by marine deposition. These fulvic acids also have a considerable content of organic material which does not absorb in the visible range. The Cm(III) complexation behavior has been studied by time-resolved laser fluorescence spectroscopy (TRLFS). Despite considerable fluorescence quenching, the complexation constant is shown to be in the same range as published values found for different typical fulvic acids.     

Comparison of the Complexation of Cu and Cd by Humic or Fulvic Acids and by Ligands Observed in Lake Waters

The complexation of Cu and Cd by ligands observed in filtered unfractionated lakewaters is compared to the complexation by humic and fulvic acids. Complexation parameters (conditional stability constants and ligand concentrations) of Suwannee River fulvic acids (FA), purified peat humic acids (HA) and of ligands in lakewater samples have been determined using the same methods (ligand-exchange and CSV (cathodic stripping voltammetry) or ASV (anodic stripping voltammetry)), and the same titration ranges of Cu, Cd and organic carbon concentrations. The performance of the used techniques is first evaluated in FA and HA suspensions, and gives comparable results with the literature values for the same materials, according to published models (5-site model, NICA model) and parameters. Model calculations using the WHAM model for FA and HA (Tipping, 1994) are also presented. The comparison of titrations of FA and HA with Cu and Cd with those of lakewater samples indicates that stronger ligands than FA and HA are present at low concentrations in the lakewaters. Specific strong ligands occur in particular in eutrophic lake waters, whereas in a lake with higher metal concentrations and low biological productivity the ligands more closely match the fulvic acid characteristics.     

Lead(II) complexation by fulvic acid: how it differs from fulvic acid complexation of copper(II) and cadmium(II)

Pb²⁺, like Cu²⁺, forms strong complexes with fulvic acids (Cd²⁺-fulvate complexes are much weaker), but Pb-fulvate precipitates at a much lower mole ratio of metal ion to fulvic acid than either Cu-fulvate or Cd-fulvate does. Physical association of Pb²⁺ with Pb-fulvate solids as well as complexation by sites still available in the precipitates probably causes the increased removal of free Pb²⁺ from solution after precipitation begins.     

华南碳酸盐岩型铀矿床中有机质及其与铀成矿的关系

华南碳酸盐岩铀矿床,分布广泛,产于泥盒—二叠纪的各地层中。矿床受岩相、构造、水文地球化学等多种条件控制。矿化与有机质关系密切,而有机质的分布受泻湖相带控制。经研究对比,与成矿有关的有机质属于腐泥型,来源于海相微体生物和藻类。铀在各地层中的含量不均匀,富里酸和腐殖酸是含铀的主要有机质。     

New version of calculation of stability constant of metal–fulvate complexes on the example of zinc fulvate

Natural macromolecular organic substances—fulvic acids—take an active part in complex formation processes and stipulate migration forms of heavy metals in natural waters. In spite of researches, experimental data on stability constants of complex compounds of fulvic acids with heavy metals (among them zinc) are heterogenous and they differ in several lines from each other. One of the reasons of such condition is ignoring an average molecular weight of the associates of fulvic acids, which finally causes the wrong results. Complex formation process between zinc (II) and fulvic acids was studied by the solubility method at pH = 8.0. ZnO suspension was used as a solid phase. Fulvic acids were isolated from Paravani lake by the adsorption chromatographic method. This article shows that during the complex formation process, every 1/5 part of an associate of fulvic acids inculcates into zinc’s (II) inner coordination sphere, as an integral ligand. So it may assume that the average molecular weight of the associate of fulvic acids which takes part in complex formation process equals to 1252. This part of the associate of fulvic acids was conventionally called an “active associate.” The average molecular weight of the “active associate” was used for determining the composition of zinc fulvate complex, the concentration of free ligand and stability constant, which equals to \(1.6 \times 10^{4}\).     

Deuterium NMR characterization of noncovalent interactions between monoaromatic compounds and fulvic acids

Deuterium nuclear magnetic resonance spectroscopy (²H-NMR) spin–lattice relaxation (T₁) experiments were used to measure noncovalent interactions between deuterated monoaromatic compounds (phenol-d₅, pyridine-d₅, benzene-d₆) and fulvic acids isolated from the Suwannee River and Big Soda Lake. Noncovalent interactions, in aqueous solution, were examined as a function of monoaromatic hydrocarbon functional groups, fulvic acid concentration and identity, and solution pH. Phenol did not exhibit noncovalent interactions with either fulvic acid at any pH. Pyridine, in a pH range from 3 to 8, interacted with Suwannee River fulvic acid, forming a bond involving the lone pair of electrons on nitrogen. Conversely, no interactions were observed between pyridine and Big Soda Lake fulvic acid; the difference in noncovalent interactions is attributed to the structural and chemical differences of the two fulvic acids. The translational and rotational molecular motion of benzene increased in the presence of both fulvic acids, indicating that in aqueous solution, fulvic acids solubilize benzene rather than forming discrete bonds as with pyridine. The results of this study demonstrate that monoaromatic functional groups, solution pH, and identity and concentration of fulvic acid can influence the type and degree of noncovalent interactions with dissolved organic matter.     

Effect of divalent cations on the kinetics of Fe(III) complexation by organic ligands in natural waters

We have investigated the kinetics of Fe(III) complexation by several organic ligands including fulvic acid, citrate and ethylenediaminetetraacetic acid (EDTA). Particular attention was given to examination of the effect of competitive divalent cations (Me: Ca²⁺ and Mg²⁺) at concentrations typical of seawater on the complexation rate. All experiments were conducted in 0.5 M NaCl solution buffered with 2 mM bicarbonate at pH 8.0 in the absence and presence of Me (25 μM-250 mM). The rate constants of complex formation determined by using the competitive ligand (5-sulfosalicylic acid) method combined with visible spectrophotometry ranged from 3.3 × 10⁴ to 3.2 × 10⁶ M⁻¹ s⁻¹. The mechanism of complexation was then examined based on a kinetic model. When EDTA was used as a ligand, Me at concentrations comparable to the ligand markedly retarded the rate of iron complex formation due to the predominance of an adjunctive pathway (where iron-ligand complex is formed via direct association of iron to Me-ligand complex). In contrast, the competing effect of Me on iron complexation by citrate and fulvic acid was observed only when the Me concentration was in excess of the ligand by more than a factor of 10-1000. The kinetic model suggests that iron complexation by fulvic acid occurs predominantly via a disjunctive pathway (where iron complexation by ligand occurs after dissociation of Me from Me-ligand complex) at concentrations of divalent cations and natural organic matter typical of natural waters including seawater and freshwater.