我国寻找超大型陆相火山岩型铀矿床的潜力评估

国外早己发现了超大型陆相火山岩型铀矿床 ,但我国迄今尚末找到。我国有广泛分布的陆相火山岩 ,能否找到此类超大型铀矿床 ,这是当前火山岩铀矿地质工作者急待解决的重要课题。本文在剖析了世界上已发现的超大型陆相火山岩型铀矿床的成矿环境和成矿条件及我国大型陆相火山岩型铀矿床成矿特点的基础上 ,对我国陆相火山岩的时空分布规律及我国主要构造火山岩带成矿潜力作了评述 ,综合得出在我国找到超大型陆相火山岩型铀矿床是有可能的 ,并确认赣杭、南岭、燕辽、大兴安岭等构造火山岩带具备形成超大型陆相火山岩型铀矿床的地质条件。上述主要构造火山岩带与其它构造火山 ( -侵入 )岩带交汇重叠部位 ,是最有希望的突破区。     

470铀矿床地球化学特征及成矿机理探讨

470火山岩型铀矿床主要有两种铀矿化类型 ,即铁—铀型和铀—钼型。含矿主岩主要为粗面岩 ,具有独特的“麻子构造” ;通过对矿床岩石化学、共生及伴生元素、稀土元素、稳定同素、成矿温度、成矿年龄等地球化学特征研究 ,分析了矿床的成矿机理 ,建立了铀成矿地球化学模式     

新疆北部浅成低温热液型金矿床成矿地球化学特征初探

产于晚古生代火山岩中的浅成低温热液型金矿床是新疆北部近期发现的一个重要的金成矿类型。通过对本区部分浅成低温热液型金矿的容矿火山岩岩石化学成分、REE分布模式、硫同位素、氢同位素、氧同位素和锶同位素及流体包裹体成分的分析与对比．讨论了其基本成矿地球化学特征,并揭示了本区浅成低温热液型金矿床与我国东部地区某些产于中生代陆相火山岩中的同类型金矿床在成矿地球化学特征上存在的一些差异。     

辽宁省二道沟金矿床地质地球化学研究(摘要)

本研究以辽宁二道沟金矿床为例，对其地质地球化学特征进行了系统全面的研究，总结了火山岩型金矿床的成矿规律，并分析了该地区的成矿前景。二道沟金矿床是一比较典型的陆相火山岩型金矿床，产于由钙碱性流纹岩、粗面英安岩、火山碎屑岩和闪长呼岩等岩石构成的陆相火山岩系中；金厂为梁金矿床产于与火山岩相毗邻的变质岩中，小长皋沟金矿床产平与火山岩相毗邻的似斑状花岗岩内，它们与二道沟金矿床在地质地球化学特征方面有明显的相似性，同属于火山岩型金矿，同受围绕对面沟花岗闪长岩岩体分布的放射状断裂所控制，是同一地质事件的产物。…     

东胜砂岩型铀矿微量元素地球化学特征初探

近年来 ,鄂尔多斯盆地在石油和天然气勘查取得重大进展的同时 ,在盆地北部东胜地区也发现了可地浸砂岩型铀矿床 ,标志着我国地浸砂岩型铀矿勘查取得了重要突破。从微量元素地球化学入手 ,初步总结了东胜地区砂岩型铀矿的微量元素地球化学特征 ,与新疆伊犁和中亚典型的层间氧化带型砂岩铀矿进行了对比 ,分析探讨了铀成矿作用 ,认为东胜砂岩型铀矿成矿作用虽与氧化还原过渡带有关 ,也具外生和深源双重性质的微量元素组合 ,不同于单一的外生水成层间氧化带型砂岩铀矿 ,铀成矿过程中有深部物质和含煤层气或油气流体参与。     

运用统计分析探讨西裘铜矿矿化作用特征

前言 自五十年代始,在我国华南褶皱系的北缘,相继发现多处成矿时代相近的细碧角斑岩型铜矿床。其中以浙江绍兴西裘铜矿和江西弋阳铁砂街铜矿发现最早,工作程度也较高(图1)。该两矿床的发现,对于嗣后在相似的地质构造条件下寻找同类矿床,起了重要的作用。     

华南花岗岩型铀矿地质特征及成矿作用

在系统梳理前人五十余年花岗岩型铀矿勘查及研究成果的基础上,应用地球化学、客观地质现象归纳等研究手段,总结了华南花岗岩型铀矿的地质特征:华南花岗岩型铀矿的产铀岩体为复式岩体,产铀花岗岩具陆内S型花岗岩特征,成矿成岩时差大,地质界面控矿特征明显。基于成矿作用"源、运、聚"的动力学过程,以成矿物质来源及成矿流体系统演化为重点,阐述了华南花岗岩型铀成矿作用,认为晚震旦世、早寒武世区域铀源层是成矿的物质来源,大规模岩浆活动之后的脉岩侵入地质事件促成了区域流体在局部演化为成矿流体,且成矿流体受重力和浮力的双势驱动,构造是成矿流体的运移通道,成矿流体的物理化学条件发生变化,从而促使矿质沉淀。     

江西邹家山铀矿绿泥石形成温度及其成矿关系

本文采用电子探针分析技术,对产于邹家山火山岩型铀矿床深部的绿泥石进行蚀变特征、化学组成、形成环境研究,并初步探讨该矿床中的绿泥石的形成环境与铀矿化关系。指出绿泥石的形成温度为217.64~295.30°C。矿脉中与铀矿物共生的绿泥石主要是鲕绿泥石,而围岩中则是蠕绿泥石和铁镁绿泥石。含矿溶液沉淀时是一个还原环境,绿泥石不仅活化了火山岩中的铀,还为铀矿化提供了良好的沉淀环境。     

江西盛源火山盆地构造对铀成矿的控制

江西盛源火山盆地铀矿地质找矿工作以往更多关注早白垩世打鼓顶组和鹅湖岭组的含矿性以及早寒武世外管坑组矿源层等问题,忽视了构造对铀成矿的控制作用。文章在收集和整理前人研究成果的基础上,结合近些年来该区铀矿地质调查工作取得的最新成果,探讨构造对该区铀成矿的控制作用,并总结铀成矿规律。不同时期、级别、性质和序次的断裂组成控矿构造系统;萍乡—广丰深断裂带控制武功山—铅山铀成矿带呈近EW向展布,较大规模的"构造结"决定铀矿田的产出位置,低级别的EW向、NE向和NW向断裂控制铀矿体的定位。     

长江中下游成矿带(江苏段)硫铁矿床成矿模式

通过分析长江中下游成矿带(江苏段)区域成矿地质条件、硫铁矿典型矿床及区域成矿特征,建立了陆相火山岩型和矽卡岩型硫铁矿床成矿模式。结合典型矿床成矿、物化探异常特征,提出长江中下游成矿带(江苏段)硫铁矿床找矿模型,这对于该区域找矿预测具有指导意义。     

Toxic effects of acetochlor, methamidophos and their combination on nifH gene in soil

Toxic effects of two agrochemicals on nifH gene in agricultural black soil were investigated using denaturing gradient gel electrophoresis （DGGE） and sequencing approaches in a microcosm experiment. Changes of soil nifH gene diversity and composition were examined following the application of acetochlor, methamidophos and their combination. Acetochlor reduced the nifH gene diversity （both in gene richness and diversity index values） and caused changes in the nifH gene composition. The effects of acetochlor on nifH gene were strengthened as the concentration of acetochlor increased. Cluster analysis of DGGE banding patterns showed that nifH gene composition which had been affected by low concentration of acetochlor （50 mg/kg） recovered firstly. Methamidophos reduced nifH gene richness that except at 4 weeks. The medium concentration of methamidophos （150 mg/kg） caused the most apparent changes in nifH gene diversity at the first week while the high concentration of methamidophos （250 mg/kg） produced prominent effects on nifH gene diversity in the following weeks. Cluster analysis showed that minimal changes of nifH gene composition were found at 1 week and maximal changes at 4 weeks. Toxic effects of acetochlor and methamidophos combination on nifH gene were also apparent. Different nifH genes （bands） responded differently to the impact of agrochemicals： four individual bands were eliminated by the application of the agrochemicals, five bands became predominant by the stimulation of the agrochemicals, and four bands showed strong resistance to the influence of the agrochemicals. Fifteen prominent bands were partially sequenced, yielding 15 different nifH sequences, which were used for phylogenetic reconstructions. All sequences were affiliated with the alpha- and beta-proteobacteria, showing higher similarity to eight different diazotrophic genera.     

Arsenic uptake by arbuscular mycorrhizal maize （Zea mays L.） grown in an arsenic-contaminated soil with added phosphorus

The effects of arbuscular mycorrhizal (AM) fungus (Glomus mosseae) and phosphorus (P) addition (100 mg/kg soil) on arsenic (As) uptake by maize plants (Zea mays L.) from an As-contaminated soil were examined in a glasshouse experiment.Non-mycorrhizal and zero-P addition controls were included.Plant biomass and concentrations and uptake of As,P,and other nutrients,AM colonization,root lengths,and hyphal length densities were determined.The results indicated that addition of P significantly inhibited root colonization and development of extraradical mycelium.Root length and dry weight both increased markedly with mycorrhizal colonization under the zero-P treatments,but shoot and root biomass of AM plants was depressed by P application.AM fungal inoculation decreased shoot As concentrations when no P was added,and shoot and root As concentrations of AM plants increased 2.6 and 1.4 times with P addition,respectively.Shoot and root uptake of P,Mn,Cu,and Zn increased,but shoot Fe uptake decreased by 44.6%,with inoculation, when P was added.P addition reduced shoot P,Fe,Mn,Cu,and Zn uptake of AM plants,but increased root Fe and Mn uptake of the nonmycorrhizal ones.AM colonization therefore appeared to enhance plant tolerance to As in low P soil,and have some potential for the phytostabilization of As-contaminated soil,however,P application may introduce additional environmental risk by increasing soil As mobility.     

Degradation of metabolites accumulated of benzo[a]pyrene by coupling Penicillium Chrysogenum with KMnO4

Several main metabolites of benzo[a]pyrene （BaP） formed by Penicillium chrysogenum, Benzo[a]pyrene-1,6-quinone （BP 1,6- quinone）, trans-7,8-dihydroxy-7,8-dihydrobenzo[a]pyrene （BP 7,8-diol）, 3-hydroxybenzo[a]pyrene （3-OHBP）, were identified by high-performance liquid chromatography （HPLC）. The three metabolites were liable to be accumulated and were hardly further metabolized because of their toxicity to microorganisms. However, their further degradation was essential for the complete degradation of BaP. To enhance their degradation, two methods, degradation by coupling Penicillium chrysogenum with KMnO4 and degradation only by Penicillium chrysogenum, were compared; Meanwhile, the parameters of degradation in the superior method were optimized. The results showed that （1） the method of coupling Penicillium chrysogenum with KMnO4 was better and was the first method to be used in the degradation of BaP and its metabolites; （2） the metabolite, BP 1,6-quinone was the most liable to be accumulated in pure cultures; （3） the effect of degradation was the best when the concentration of KMnO4 in the cultures was 0.01% （w/v）, concentration of the three compounds was 5 mg/L and pH was 6.2. Based on the experimental results, a novel concept with regard to the bioremediation of BaP-contaminated environment was discussed, considering the influence on environmental toxicity of the accumulated metabolites.     

Impact of atrazine and nitrogen fertilizers on the sorption of chlorotoluron in soil and model sorbents

Sorption of chlorotoluron in ammonium sulfate, urea and atrazine multi-solutes system was investigated by batch experiments. The results showed application of nitrogen fertilizers to the soil could affect the behavior of chlorotoluron. At the same concentration of N, sorption of chlorotoluron decreased as the concentration of atrazine increased on the day 0 and 6 in soil, respectively. The sorption of chlorotoluron increased from 0 to 6 d when soils were preincubated with deionized water, ammonium sulfate and urea solution for 6 d. That indicated incubation time was one of the most important factors for the sorption of chlorotoluron in nitrogen fertilizers treatments. The individual sorption isotherms of chlorotoluron in rubbery polymer and silica were strictly linear in single solute system, but there were competition sorption between pesticides or between pesticides and nitrogen fertilizers. That indicated the sorption taken place by concurrent solid-phase dissolution mechanism and sorption on the interface of water-organic matter or water-mineral matter.     

Potential of plant polyphenol oxidases in the decolorization and removal of textile and non-textile dyes

In this study an effort has been made to use plant polyphenol oxidases; potato （Solanum tuberosum） and brinjal （Solanum melongena）, for the treatment of various important dyes used in textile and other industries. The ammonium sulphate fractionated enzyme preparations were used to treat a number of dyes under various experimental conditions. Majority of the treated dyes were maximally decolorized at pH 3.0. Some of the dyes were quickly decolorized whereas others were marginally decolorized. The initial first hour was sufficient for the maximum decolorization of dyes. The rate of decolorization was quite slow on long treatment of dyes. Enhancement in the dye decolorization was noticed on increasing the concentration of enzymes. The complex mixtures of dyes were treated with both preparations of polyphenol oxidases in the buffers of varying pH values. Potato polyphenol oxidase was significantly more effective in decolorizing the dyes to higher extent as compared to the enzyme obtained from brinjal polyphenol oxidase. Decolorization of dyes and their mixtures, followed by the formation of an insoluble precipitate, which could be easily removed simply by centrifugation.     

Effects of two sludge application on fractionation and phytotoxicity of zinc and copper in the soil

The potential harm of heavy metals is a primary concern in application of sludge to the agricultural land. A pot experiment was conducted to evaluate the effect of two sludges on fractionation of Zn and Cu in soil and their phytotoxicity to pakchoi. The loamy soil was mixed with 0%, 20%, 40%, 60% and 80% (by weight) of digested sewage sludge (SS) and composted sludge (SC). The additions of both sludges caused a significant raise in all fractions, resulting in that exchangeable (EXCH) and organic bound (OM) became predominance of Zn and organic bound Cu occupied the largest portion. There was more available amount of Zn and Cu in SS treatments than SC treatments. During the pot experiment, the concentration of Zn in EXCH, carbonate (CAR) and OM and Cu in EXCH and OM fractions decreased in all treatments, so their bioavailability reduced. Germination rate and plant biomass decreased when the addition rate was high and the best yield appeared in 20% mixtures at the harvest of pakchoi. The two sludges increased tissue contents of Zn and Cu especially in the SS treatments. Zn in pakchoi was not only in relationship to ΔEXCH and ΔCAR forms but also in ΔOM forms in the sludge-soil mixtures. Tissue content of Cu in pakchoi grown on SC-soils could not be predicted by ΔEXCH. These correlation rates between Zn and Cu accumulation in pakchoi and variation of different fractions increased with time, which might indicate that sludges represented stronger impacts on the plant in long-term land application.     

Intraspecific differences in effects of co-contamination of cadmium and

A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p ＜ 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.     

Removal of heavy metals from sewage sludge by low costing chemical method and recycling in agriculture

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Isolation and preliminary characterization of a 3-chlorobenzoate degrading bacteria

A study was conducted to compare the diversity of 2-, 3-, and 4-chlorobenzoate degraders in two pristine soils and one contaminated sewage sludge. These samples contained strikingly different populations of mono-chlorobenzoate degraders. Although fewer cultures were isolated in the uncontaminated soils than contaminated one, the ability of microbial populations to mineralize chlorobenzoate was widespread. The 3- and 4-chlorobenzoate degraders were more diverse than the 2-chlorobenzoate degraders. One of the strains isolated from the sewage sludge was obtained. Based on its phenotype, chemotaxonomic properties and 16S rRNA gene, the organism S-7 was classified as Rhodococcus erythropolis. The strain can grow at temperature from 4 to 37℃. It can utilize several （halo）aromatic compounds. Moreover, strain S-7 can grow and use 3-chlorobenzoate as sole carbon source in a temperatures range of 10-30℃ with stoichiometric release of chloride ions. The psychrotolerant ability was significant for bioremediation in low temperature regions. Catechol and chlorocatechol 1,2-dioxygenase activities were present in cell free extracts of the strain, but no （chloro）catechol 2,3- dioxygenase activities was detected. Spectral conversion assays with extracts from R. erythropolis S-7 showed accumulation of a compound with a similar UV spectrum as chloro-cis,cis-muconate from 3-chlorobenzoate. On the basis of these results, we proposed that S-7 degraded 3-chlorobenzoate through the modified ortho-cleave pathway.     

Single and joint effects of pesticides and mercury on soil urease

The influence of two pesticides including chlorimuron-ethyl and furadan and mercury （Hg） on urease activity in 4 soils （meadow burozem and phaeozem） was investigated. The soils were exposed to various concentrations of the two pesticides and Hg individually and simultaneously. Results showed that there was a close relationship between urease activity and organic matter content in soil. Chlorimuron-ethyl and furadan could both activate urease in the 4 soils. The maximum increment of urease activity by chlorimuronethyl was up to 14%-18%. There was almost an equal increase （up to 13%-21%） in the urease activity by furadan. On the contrary, Hg markedly inhibited soil urease activity. A logarithmic equation was used to describe the relationship （P〈0.05） between the concentration of Hg and the activity of soil urease in the 4 tested soils. Semi-effect dose （ED50） values by the stress of Hg based on the inhibition of soil urease in the 4 soils were 88, 5.5, 24 and 20 mg/kg, respectively, according to the calculation of the corresponding equations. The interactive effect of chlorimuron-ethyl or furadan with metal Hg on soil urease was mainly synergic at the highest tested concentrations.