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1.
An area where fresh volcanic ash has fallen was found to have concentrations of Th and U that exceed the background values by factors of 270 and 32, respectively, for natural waters and by factors of 35 and 6 for plants. The soils and bottom deposits were not enriched in Th and U after a single ashfall; however the Th/U ratio decreased in these natural media relative to the background values, indicating a genetic affinity with young ashes where the concentration of highly mobile (relative to thorium) uranium is higher compared with older ashes. For areas far from active ashfalls, where the soils were formed on acid ash, we found higher background concentrations of Th and U in soils, surface waters, and bottom deposits, as well as higher gamma-ray background values above the Earth’s surface relative to the areas where the soils were formed on basic and intermediate ashes. This research resulted in the identification of two radioecological provinces in Kamchatka, viz., a Northern and a Southern province.  相似文献   

2.
Concentrations of Th and U in fresh ash ejected by active volcanoes in Kamchatka are generally considerably below their Clarke values in their respective types of rock. The bulk concentrations of Th and U in andesitic and basaltic ashes do not show any obvious differences. The concentrations of their mobile forms decrease with increasing basicity of the ash. We revealed overall positive linear trends in the series of bulk concentrations for Th and U and a negative trend of Th/U in ashes that have been arranged over eruption year. Considerable quantities of mobile forms of radioactive elements fall during ashfalls in dissolved form or are sorbed by falling snow directly from the dispersive medium of volcanic aerosols. The original fractions of all of the mobile forms are 0.68–1.93% for Th and 1.16–3.21% for U. The bulk of these come to the Earth’s surface during eruptions when no snow cover was available. The quantities of mobile forms of Th and U were considerably decreased when ejected by winter-time eruptions during the time they resided in the snow.  相似文献   

3.
The results of studying the elemental composition of surface continental waters in the European Russia from tundra to arid zone are discussed. The relative concentrations of elements in the solid residue of waters from various natural-climatic zones are evaluated, and the enrichment or dispersion of continental waters by these elements are analyzed as compared with their clarkes in the rocks that occur in the catchment areas. The coefficients of migration in water are evaluated, and the major elements with respect to which surface waters enrich under anthropogenic load are identified. The territorial distribution of higher concentrations of the most hazardous elements in waters of lakes is characterized.  相似文献   

4.
The Sumatra (Indonesia) earthquake of December 26, 2004 (M w = 9.0?9.3), is among the strongest seismic events (occupying the second to fourth place) recorded in the epoch of instrumental seismological observations. In addition, this earthquake appears to be the first event of such a scale for which results of up-to-date high-precision geodetic measurements are available. Therefore, it is of particular interest for studies of geodynamics of mobile belts, seismogenic zones, and the Earth’s crust as a whole. The available geological, geophysical, and geodetic data for the Mediterranean-Caucasian segment of the Alpine-Himalayan mobile belt, the Greater Caucasus, and the Tajik depression suggest that the tectonic structure, geological zonality, seismicity, and present-day geodynamics of these structural elements of the Earth’s crust are controlled by the interaction of two different mechanisms of tectogenesis. First, this is the mechanism of independent self-development of the aforementioned structural elements and, first of all, the mobile belt as a whole; this mechanism acts through an intense increase in the volume and area of laminated rocks of the crust/lithosphere, apparently, due to the influx of additional mineral material supplied by an ascending flow of deep fluids. The second type of mechanisms is related to the external plate-tectonic action on the mobile belt and the other structural elements due to lateral movements of lithospheric plates. The joint analysis of geological, geodetic (GPS), and seismological data on the Sumatra earthquake area shows that these two mechanisms also act in the Indonesian part of the Alpine-Himalayan mobile belt. However, the Sumatra earthquake itself is a result of an independent (unrelated to plate tectonics) process in the mobile belt rather than the convergence of adjacent lithospheric plates.  相似文献   

5.
Inductively coupled plasma atomic emission spectrometry and inductively coupled plasma MS are the major analytical tools for trace elements in environmental matrices, however, the underestimate of certain trace elements in analysis of air particulate matter by these two techniques has long been observed. This has been attributed to incomplete sample digestion. Here, we demonstrate that the combined effects of sample digestion, air filter impurities, and post‐adsorption of the analytes contribute to the interference of the analysis. Particular attention should be paid to post‐adsorption of analytes onto air filters after acid digestion.  相似文献   

6.
In the Neogene volcanic province of Northern Tanganyika are surface limestones which cover large areas, despite variation and unsuitability of the bedrock. Field mapping has proved the existence of bedded carbonate tuffs dipping off Recent vents, and the field relationships and the trace element analyses prove the tuffs to be carbonatitic. Trace element analyses of some of the «surface limestones» show that they also have carbonatitic affinities, and the inference is that some, if not all, of the limestones are consolidated carbonatitic ashes. The presence of limestone in the area surrounding other carbonatite volcanoes is examined in the light of this evidence.  相似文献   

7.
This study investigates the potential for leaching of coal trace elements to seawater from a grounded bulk carrier. The coal type and ecological scenario was based on the grounding of the "Shen Neng" (April 2010) at Douglas Shoal located within the Great Barrier Reef (Queensland, Australia). The area is of high ecological value and the Queensland Water Quality Guidelines (2009) provided threshold limits to interpret potential impacts. Coal contains many trace elements that are of major and moderate concern to human health and the environment although many of these concerns are only realised when coal is combusted. However, "unburnt" coal contains trace elements that may be leached to natural waterways and few studies have investigated the potential ecological impact of such an occurrence. For example, coal maritime transport has increased by almost 35% over the last five reported years (Jaffrennou et al., 2007) and as a result there is an increased inherent risk of bulk carrier accidents. Upon grounding or becoming submerged, coal within a bulk carrier may become saturated with seawater and potentially leach trace elements to the environment and impact on water quality and ecological resilience. The worst case scenario is the breakup of a bulk carrier and dispersal of cargo to the seafloor.  相似文献   

8.
Major and trace element analyses of the Luochuan loess-paleosol sequence in China were performed in order to understand the cheniical weathering processes occurring on the I.oess Plateau during the last 600 ka. Results reveal that most elements in the loess remain immobile durlng chemical weathering. The typical stable elements are Al, K, Ti, Rb and REE, while the main mobile elements are Ca, Sr, P, Mg and Na. 120ess and paleosol experience the incipient stage of chemical weathering characterized by acid leaching and carbonate dissolution. Alteration of silicates in the sequence seems to be limited. Features of less chemical weathering of the loess and paleosol could he indicators for the dry-cold clinlate dominated on the Loess Plateau during the Quaternary. Project supported hy thc Nzitional Natural Science Foundation of China  相似文献   

9.
赣南素有“世界钨都”之称,而龙南-定南-全南(简称“三南”)地区是世界钨都中的重要钨铋成矿区,钨铋成矿与三南地区广布的泥盆纪地层密不可分;由此本文通过对三南地区的泥盆系的微量元素的分布及其丰度、以及W、Bi等成矿元素在不同岩性中的丰度等进行了初步分析与讨论,认为W成矿元素在泥盆系中丰度仅次于寒武纪地层,高于其它地层,并高出地壳克拉克值的2~4倍,而Bi元素则高达几十倍。在细碎屑岩石中含量最高,与钨铋成矿关系最为密切。  相似文献   

10.
Lewisian gneiss geochemistry and Archaean crustal development models   总被引:1,自引:0,他引:1  
The geochemistry of Lewisian amphibolite-facies gneisses from northwest Scotland is described with particular reference to the rare earth elements (REE) and compared with the geochemistry of Lewisian granulite-facies gneisses. The results show that there are no significant differences between “Laxfordian” amphibolite-facies and “Scourian” granulite-facies gneisses in terms of REE and other immobile trace elements (at equivalent silica levels), although the mobile radioactive heat-producing elements, K, Rb, Th, U, are significantly lower in the granulites. In both types the basic gneisses have moderately fractionated REE patterns while the intermediate and acid gneisses have strongly fractionated REE patterns with low heavy REE abundances and decreasing levels of total REE with increasing SiO2. The most silicic gneisses develop large positive europium anomalies.These gross chemical similarities between gneisses from intermediate (amphibolite-facies) and lower (granulite-facies) crustal levels constrain models for the evolution of the Archaean crust. The depletion of K, Rb, Cs, Th and U in granulites, but not other incompatible trace elements cannot be explained by magmatic processes. The positive Eu anomaly in the more siliceous gneisses of both facies is a function of the primary processes of crustal generation and not secondary processes such as intracrustal melting or fractional crystallisation. Fractionation of radioactive heat-producing elements from other trace elements is a result of granulite-facies metamorphism with these elements being removed by an active fluid phase. The apparent lack of partial melting in lower crustal granulites suggests a model for Archaean crustal growth largely through underplating by primary tonalitic magmas.  相似文献   

11.
The European Water Framework Directive (WFD) commits European Union member states to achieving good ecological status in all water bodies by 2015. For sediments the definition of good chemical status is based on numerical sediment quality guidelines. The aqua regia fraction is thus used for the evaluation of heavy metal concentrations in sediments. The chemical constituents in sediments responsible for mobility and toxicity are not considered generally. This article presents the combining of the sequential BCR procedure, for determining the chemical species of relevant elements, with the geoaccumulation index principle a numerical classification method for sediment quality guidelines. Using the BCR method it can be demonstrated that changes in element speciation can lead to more highly mobile species of trace elements which may affect the hazardous potential of sediments despite the “good chemical status” classification for aqua regia digestions. The Klinke stream is an urban surface water body located in Magdeburg, the state capital of Saxony‐Anhalt, Germany. Using this stream as an example it is shown that this additional information helps to describe the dynamics and discharge of the trace elements Al, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Rb, Sr, Mo, Pd, Cd, Sb, Ba, Pb, Bi, and U into the Elbe River from urban water bodies.  相似文献   

12.
Investigation on the Pollution Potential of Waterworks Sludges Several contaminated sludges from water treatment plants with known or estimated concentrations of trace elements were investigated for their leaching characteristics and long-term stability using standard and advanced test procedures. Potentially hazardous elements in the sludge are zinc, nickel, and arsenic with concentrations of up to 1.2 g/kg dry matter (mass). Preliminary sorption tests with synthetic sludge components like iron hydroxide, manganese oxide, silicate clay minerals, and chitine powder as a model organic component showed that Cu is associated with the organic phase wheras arsenic is predominantly bound to the iron oxide minerals. The recently suggested pHstat test procedure was used to assess the leaching characteristics of metals at typical pH values. This procedure was compared with the DEV-S4 test, the current standard test in Germany, consisting of a simple lixiviation of the solids with water, without pH control. The pHstat test yields results which are much better to interprete than those obtained by the DEV-S4 procedure. The iron and manganese sludges are well buffered against changes in pH and redox potential so that low pH values and/or reducing conditions can hardly occur. Thus, in deposited material a sudden leaching of heavy metals is unlikely and due to the presence of iron and manganese oxides the pentavalent arsenic is protected against conversion into the highly mobile trivalent form at neutral to low pH. Co-deposition with reducing organic matter and alkaline stabilisation material or waste (like fly ash) could influence the binding properties and should be strictly avoided.  相似文献   

13.
Major and trace elements as well as strontium isotopic composition have been analyzed on the acid-insoluble (AI) phase of the loess-paleosol sequence from Luochuan, Shaanxi Province, China. Results show that the chemical composition of AI phase of loess and paleosols is distinctive to the average composition of upper continental crust (UCC), characterized by depletion of mobile elements Na, Ca and Sr. The distribution pattern of elements in AI phase reveals that initial dust, derived from a vast area of Asian inland, has suffered from Na- and Ca-removed chemical weathering compared to UCC. Some geochemical parameters (such as CIA values, Na/K, Rb/Sr and87Sr/86Sr ratios) display a regular variation and evolution, reflecting that the chemical weathering in the source region of loess deposits has decreased gradually since 2.5 Ma with the general increase of global ice volume. This coincidence reflects that the aridity of Asian inland since the Quaternary is a possible regional response to the global climate change.  相似文献   

14.
Suspended particulate matter (SPM) and colloidal matter (COM) in annual dry and wet deposition samples in urban Guangzhou were for the first time collected, and their trace metals were investigated by using inductively coupled plasma mass spectrometry (ICP-MS). The deposition flux of SPM and of metal elements varied largely among the investigated seasons, and reached the maximum in spring. The correlation analysis indicated that significant correlations existed among some of the metal elements in the deposition samples. The enrichment factors (EF) of metals in COM in the deposition ranging from 79.66 to 130,000 were much higher than those of SPM ranging from 1.65 to 286.48, indicating the important role of COM. The factor analysis showed that emissions from street dust, non-ferrous metal production, and heavy fuel oil were major sources of the trace metals. Positive matrix factorization (PMF) model was used to quantitatively estimate anthropogenic source.  相似文献   

15.
Mesozoic dolerites from two areas of Morocco, the High Atlas fold belt between Marrakech and Demnat and the Anti-Atlas belt in the area of Foum Zquid, are most high-Ti quartz-normative tholeiites whichi in many respects resemble Mesozoic dolerite dikes from eastern North America. The dolerites display a wide range of major and trace element compositions, some of which are due to fractional crystallization. The doleritic sequences from High Atlas also show vertical stratigraphic zonation which is characterized by a progressive depletion of lithophile elements toward the top. This trend together with regularities of trace element ratio variations are indicative of a dynamic melting of an initially homogeneous source. It is suggested that the continental upper mantle source for dolerites of Morocco was enriched in several incompatible elements in comparison with the upper mantle source for ocean floor tholeiites.  相似文献   

16.
Glass separates from 115 ash layers derived from the Kamchatkan (DSDP Site 192; 34 layers), the eastern Aleutian (DSDP Site 183; 56 layers) and the Alaska Peninsula (DSDP Site 178; 25 layers) volcanic arcs have been analyzed for up to 28 elements. In addition, the abundance and diversity of associated mafic phenocrysts have been evaluated. The resulting data set has made possible an evaluation of the late Miocene to Recent changes in composition of ashes derived from North Pacific volcanic arcs and of the factors controlling the evolution of highly siliceous magmas.We find no evidence for a general transition from arc tholeiite to calc-alkalic magma parentage of ashes derived from the volcanic arcs during the last 10 m.y., but instead find 0.1- to 0.5-m.y. intervals during which particular types of volcanism are prevalent. Most convincing is the transition from arc tholeiite to calc-alkalic for ashes derived from Kamchatka during the last 0.8 m.y., a change believed to be associated with a landward shift in the site of magma generation. Considered together, ashes derived from North Pacific volcanic arcs have been becoming more siliceous during the last 1.5 m.y. and may be associated with accelerated subduction during the same time interval.Hydrous phenocrysts (e.g., biotite) are typically associated with low-silica deep-sea ashes, but not with terrestrial volcanic rocks of comparable silica contents, suggesting the important role of water in the evolution of siliceous magma. REE patterns and relative abundances of mafic phenocrysts demonstrate the importance of fractional crystallization in controlling the evolution of highly siliceous arc magmas. REE increase with increasing silica, but become less concentrated in ashes with SiO2 > 64%. Eu anomalies increase throughout the SiO2 range. Initial fractionation is dominated by clinopyroxene and plagioclase with amphibole strongly influencing fractionation above 64% SiO2.  相似文献   

17.
In order to assess the response of benthic foraminifera to trace element pollution, a study of benthic foraminiferal assemblages was carried out into sediment samples collected from the Santa Gilla lagoon (Sardinia, Italy). The lagoon has been contaminated by industrial waste, mainly trace elements, as well as by agricultural and domestic effluent. The analysis of surficial sediment shows enrichment in trace elements, including Cr, Cu, Hg, Ni, Pb and Zn. Biotic and abiotic data, analyzed with multivariate techniques of statistical analysis, reveal a distinct separation of both the highly polluted and less polluted sampling sites. The innermost part of the lagoon, comprising the industrial complex at Macchiareddu, is exposed to a high load of trace elements which are probably enhanced by their accumulation in the finer sediment fraction. This area reveals lower diversity and higher percentages of abnormalities when compared to the outermost part of the lagoon.  相似文献   

18.
Riassunto Premessi i dati di osservazione sulle sabbie e sulle ceneri proiettate dall'Etna nella fase esplosiva del 16-III-1940 e trasportate dai venti fino in Calabria, si espongono le caratteristiche fisiche dei materiali caduti e particolarmente quelle granulometriche in rapporto alla distanza di trasporto, confrontandole con le ceneri cadute nell'isola di Stromboli in occasione delle esplosioni di questo vulcano del 14-XII-1937 e del 22-V-1938.
Summary After some remarks on the sands and the ashes projected by the Etna in the explosive period of March the 16th, 1940, and carried by the wind as far as Calabria, the physical characters of the material fallen and particulary the granulometrical ones are exposed in relation to the distance of carriage, making some comparisons with the ashes fallen on the Isle of Stromboli in the occasion of the explosions of this volcano in Dec. the 14th, 1937, and in May, the 22th, 1938.

Zusammenfassung Der Sand und die Aschen geworfen durch die Explosion der Etna am 16. 3. 1940 und die bis Kalabrien durch den Wind transportiert wurden, sind vom Verf. physikalisch untersucht worden und zwar besonders nach der Verteilung der Korngrösse im Verhältnis mit den Transport-Distanzen. Die Mitteilung der Ergebnisse geschieht mit Vergleichung derjenigen die sich auf die Aschen vom Stromboli beziehen, welche von diesem Vulkan am 1937 und 1938 geworfen worden sind.
  相似文献   

19.
Mineralogy and geochemistry of the four main workable coal seams (No.6, No.7, No.8, and No.11) of Late Permian age from the Songzao Coalfield, Chongqing, Southwest China, were examined using in- ductively coupled plasma-mass spectrometry (ICP-MS), X-ray fluorescence spectrometry (XRF), cold-vapor absorption spectrometry (CV-AAS), ion-selective electrode (ISE), scanning electron mi- croscopy equipped with an energy-dispersive X-ray spectrometer (SEM-EDX), and X-ray diffraction analysis (XRD). The results showed that the main workable No.8 Coal that accounts for about 60% of the total coal reserves in the Songzao Coalfield was not enriched in hazardous trace elements. The No.11 Coal has high concentrations of alkaline elements, Be (9.14 μg/g), Sc (12.9 μg/g), Ti (9508 μg/g), Mn (397 μg/g), Co (23.7 μg/g), Cu (108 μg/g), Zn (123 μg/g), Ga (32 μg/g), Zr (1304 μg/g), Nb (169 μg/g), Hf (32.7 μg/g), Ta (11.4 μg/g), W (24.8 μg/g), Hg (0.28 μg/g), Pb (28.1 μg/g), Th (24.1 μg/g), and rare earth elements (509.62 μg/g). The concentration of Nb and Ta in the No. 11 Coal is higher than the industrial grade, and their potential utilization should be further studied. Besides pyrite, quartz, calcite, and clay minerals, trace minerals including chalcopyrite, marcasite, siderite, albite, mixed-layer clay minerals of illite and smectite, monazite, apatite, anatase, chlorite, and gypsum were found in the No.11 Coal. It should be noted that alabandite of hydrothermal origin and anatase occurring as cement were identi- fied in coal. In addition, the clayey microbands derived from alkaline volcanic ashes were identified in the coal. The dominant compositions of these clayey microbands were mixed-layer clay minerals of illite and smectite, which were interlayered with organic bands. The modes of occurrence of alkaline volcanic ash bands indicate that the volcanic activities were characterized by the multiple eruptions, short time interval and small scale for each eruption during peat accumulation. The alkaline volcanic ashes were the dominant factors for the enrichment of alkaline elements, Nb, Ta, Zr, Hf, and rare earth elements, and the sulfide minerals are the main carriers of Ga, Cu, and Hg in the No. 11 Coal.  相似文献   

20.
Four 2–3 m sediment cores were taken at the sites on the periphery of mussel raft concentrations in the subtidal zone of the inner Ría de Vigo (Galicia, NW Spain) with a view to evaluate the potential risk to mariculture from sediment-borne trace elements (As, Cd, Cr, Cu, Mn, Ni, Pb and Zn). The distribution of each of these elements in reactive, organic, pyrite and silicate-bound fractions was determined at 64 samples, and these data were used to calculate the degree of trace metal pyritization (DTMP) of each metal/metalloid. In the top 10–20 cm, relatively oxic conditions led to As, Cd, Cu, Pb and Zn having large reactive fractions due to their association with Fe and Mn oxyhydroxides. At lower levels, anoxic conditions favoured by intense diagenesis led to the precipitation of trace metals and metalloids as sulphides, with or without association with pyrite. Particularly large pyrite fractions in the 20–100 cm layer are attributed to the organic matter of this layer being more marine in origin than that of deeper sediments. DTMP was greatest for Cu and As, and least for Pb, Zn and Cr. The risk of trace element toxicity in the event of disturbances instituting oxic conditions in these sediments is discussed.  相似文献   

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