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1.
火山活动具多旋回性,一个火山活动旋回的岩浆作用产物及其形成的火山构造形迹具时空分布协调性,同一旋回的火山构造在空间上呈串珠状或并列式展布,不同旋回的火山构造在空间上呈叠置式展布;火山喷发类型与火山岩相具一致性,岩相及相序是推演古火山演化历史、恢复古火山机构的主要依据,亦是组成火山地层并且成因意义的单元;不同旋回火山机构内的火山地层层序的综合、叠置是建立区域火山地层层序的基础;火山构造是火山岩区地质构造的主要内容,以区域构造、火山构造、火山岩浆作用产物的岩相为内容的火山岩相构造图是揭示火山岩区地质构造特征的综合性图件;环形火山构造叠置与区域线形构造交织分布组成线─环形境构造格局.是火山岩区所特有的构造面貌,在火山地质图上应得到充分的体现;。根据上述认识,对陆相火山岩区作为火山地层填图单元的岩石地层单位群─组─段─层划分提出了方案,建议用旋回─组─岩相─层(即火山构造─组─岩相─层)四级作为火山地层划分单位和填图单元,其中旋回火山构造一致,组与火山机构演化阶段一致,岩相与火山喷发类型一致,层为岩相内容的补充。据此填制的火山地质图才能真正成为反映火山岩浆作用及其产物的特色和具普遍意义的图件。  相似文献   

2.
本文是应用火山构造一岩相法对浙、闽、赣这一特大型火山岩区,进行区域性综合研究的尝试。除阐明了所用基本方法的根据、实质等要点外;首次从旋回角度系统探讨本区统一旋回地层的划分,火山构造类型、构造格局与火山杂岩的特征及其时空分布与演化等重大基础地质问题,提出与传统认识不同的看法。  相似文献   

3.
三界谷来地区主要出露中、新生代火山岩。进行 1/5万区域地质调查时,采用火山活动旋回-火山构造-火山地层-岩相、岩性-体化思路,按照同旋回火山机构或火山喷发区为单元,确定岩石地层单位和填图单元。火山岩划分为九种岩相类型,建立了两个岩相模式和一个三相一体成因模式。根据火山岩浆作用的旋回性及其产物与火山构造形迹时、空、成因一致性原理,将中、新生代火山岩浆作用分为四个火山活动旋回,圈定了相应的火山机构或火山喷发中心,建立了竹田头复活破火山演化模式。新生代玄武岩中发现二辉斜长麻粒岩等深源包体,为研究区域深部地质作用过程提供了证据。侵入岩按岩石谱系单元划分了七个岩石单元一个超单元,将侵入岩-潜火山岩-火山岩作为岩浆作用整体研究,为正确阐明岩浆作用及其演化规律奠定了基础。区域线型构造发育,与环形火山构造组合,形成火山岩区特有的线一环构造格局。中上元古界陈蔡群变质岩划分为上、下两个岩组,探讨了变质岩的原岩性质及其形成的大地构造环境。  相似文献   

4.
西藏措麦地区处于冈底斯火山—岩浆弧的中段,新生代火山活动强烈,火山岩相发育齐全。根据火山喷发类型、火山物质搬运方式和定位环境,可划分为爆发相、爆溢相、喷溢相、侵出相、潜火山岩相、火山通道相、喷发—沉积相等7大类型。再依据区内火山活动特点,火山相序及相组合特征,结合火山沉积地层及其接触关系,可将其火山活动划分四个喷发—沉积旋回,依序对应于典中组、年波组、帕那组、鱼鳞山组四个岩石地层单位。文章阐述了各类型火山岩相的基本特征,对各火山岩相序、相组合及火山活动旋回作了初步分析和归纳,对提高整个冈底斯地区火山岩研究程度,具有一定的实际意义。  相似文献   

5.
本书反映了近年来中国东南大陆地区火山地质研究的最新成果。作者运用古生物化石组合、同位素地质年龄及构造旋回与火山活动旋回对比等综合资料,并结合基底构造、矿化分布等研究成果,对本区中生代火山活动旋回进行了划分与区域对比;提出了古火山构造类型、级别划分方案,并对各级火山构造进行了解剖;对区域火山构造基本特征以及火山旅回与火山构造的控矿意义进行了总结,提出了找矿方向的一些看法;对本区中生代火山岩形成的大地构造环境、各旋回火山活动的不同构造控制条件也作了分析与总结。本书对地质勘探探、科研、教学单位的地质人…  相似文献   

6.
中国东南沿海中生代火山作用基本特征   总被引:3,自引:0,他引:3  
中国东南沿海自晚侏罗世到白垩纪火山活动分为二期、四个旋回,在空间上有迁移性,在时间上与侵入活动呈交替式演变。建立火山碎屑流等五种岩相模式,岩浆爆发占主导地位,同时存在蒸气岩浆爆发。确定破火山口、火山穹隆和锥火山为火山构造基本类型。由火山作用与区域构造作用、沉积作用控制形成火山沉积洼地、火山构造洼地和火山构造隆起。提出不同类型火山构造组合形式和相互演化关系。火山岩系列属高钾钙碱系列,晚期则具双模式性质。它们的地球化学型式兼具大陆边缘和大陆板内双重特性。  相似文献   

7.
粤东中生代火山旋回划分及对比   总被引:1,自引:0,他引:1  
本文在基本查明火山岩系地层层序及变化的基础上,将粤东地区中生代火山岩划分为上、下两个岩系,四个旋回,对各旋回特征作了简要总结,并进行了区域对比分析。  相似文献   

8.
东南沿海火山、侵入杂岩同位素年代学   总被引:1,自引:0,他引:1  
本文运用同位素年代学方法对东南沿海火山、侵入杂岩进行系统研究。认为火山活动起止时间因地而异,粤东为180—75Ma;渐、闽为135—105Ma,东西两区也有差别。发现粤东高基坪群下群存在180—170Ma的早侏罗世火山岩。全区火山活动可划分为七个旋回。火山岩与侵入岩同时、同源、同空间和同步迁移。火山活动先由南向北,再由北向南逆转;东西方向由大陆向海洋推移演化。  相似文献   

9.
溧水火山岩地区位于长江下游南岸,东邻茅山山脉,西接宁芜火山岩盆地,是长江中下游一系列中生代陆相火山岩分布区之一。该区火山岩系,按喷发次序、岩石组合、喷发间断等,自下而上,可以划分为四个火山喷发旋回,即龙王山旋回,主要由中—基性熔岩、次火山岩和相应的火山碎屑岩组成,东芦山旋回,主要由中碱性和基性熔岩、次火山岩及相应的火山碎屑岩组成,观山旋回,主要由中碱性—碱性熔岩、次火山岩及火山碎屑岩组成;甲山旋回,全部由酸性熔岩、次火山岩及火山碎屑岩组成。有关各旋回的主要岩石类型和主要火山岩的岩石化学成份见表1、2。  相似文献   

10.
东南沿海陆相多旋回双模式火山岩   总被引:2,自引:0,他引:2  
以闽东永泰地区为实例,具体阐述东南沿海陆相多旋回双模式火山岩及其区域性分布特点。早白垩世为主要形成期,与世界其它地区以太古代为主体有所不同。区内双模式火山岩为主元结构,Ⅰ旋回(下组合)为沉积岩——玄武岩——流纹质凝灰岩;Ⅱ旋回(上组合)为沉积岩——碱性玄武岩——流纹质凝灰岩;Ⅲ旋回为沉积岩——玄武岩——火山集块岩及钾长流纹岩,其形成的构造环境为活动大陆边缘板内拉张环境,岩浆结晶温度大约在970—1156℃,估算过渡岩浆房形成深度约3.5—5km。  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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.  相似文献   

14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
RemovalofheavymetalsfromsewagesludgebylowcostingchemicalmethodandrecyclinginagricultureWuQitang,NyirandegePascasie,MoCehuiF...  相似文献   

19.
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.  相似文献   

20.
Single and joint effects of pesticides and mercury on soil urease   总被引:3,自引:3,他引:3  
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.  相似文献   

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