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1.
地球表层是由山水林田湖草等要素构成的互动和互馈的复杂系统,这些要素中化学元素的互动和互馈过程均可驱动化学元素分布模式的变化。本文以系统的1∶25万土地质量地球化学调查数据为基础,讨论了中国西南地区土壤中常量元素、亲生物元素、卤族元素、重金属元素分布模式的驱动机制和互动过程。结果发现成土母质决定了土地资源中化学元素的自然状况,表生地球化学动力学过程重塑了表层土壤中元素分布模式,生物地球化学过程驱动了土地质量的演化趋势,强烈的人类活动(如矿业活动)破坏了元素分布的自然演化规律。表生地球化学动力学理论的提出将引领山水林田湖草生命共同体知识体系构建和土地资源地球化学综合调查技术的革新。  相似文献   

2.
The Earth's surface is a complex system involving mutual interactions of its many components, including mountains, rivers, forests, farmlands, lakes and grasses. The interaction and mutual feedback of chemical elements in Earths surface layer can drive changes in chemical elemental distribution patterns. In this study, we evaluated the mechanisms and interactions driving the distribution patterns of macroelements, probiotics, halogens and heavy metals in soils in Southwest China, based on a systematic geochemical land-quality survey at a scale of 1250000. The results showed that the parent material determines the natural state of chemical elements in land resources. Epigenetic geochemical dynamics reshapes the distribution patterns of chemical elements in top soil; biogeochemical processes drive the evolutionary trends of land quality; and human activities, such as mining, disrupt the natural evolution of chemical elemental distribution patterns. The establishment of an epigenetic geochemical dynamics theory allows the construction of a framework for understanding the Earths surface layer and promoting technological innovations for the comprehensive geochemical investigation of land resources.  相似文献   

3.
We examined four dispersed, coalified ovules, Trigonocarpus grandis, of medullosalean seed-fern affinity from the Late Pennsylvanian age Sydney Coalfield, Canada, which represent the larger type of the 7–8 cm trigonocarpalean form species. At first glance it appears that the ovules are preserved like the usual Carboniferous foliar compressions, i.e. one coalified layer with one preserved anatomical tissue, the cuticle. However, careful sample preparation uncovered at least three coalified layers, and Schulze’s oxidative maceration process, which dissolves the coalified material, revealed several tissue layers. Altogether, eight sample forms were defined: (i) coalified layer, (ii) cuticle A, (iii) cupric + vitrain, (iv) vitrain, (v) cupric, (vi) cuticle B, (vii) alkaline solution and (viii) added coal seam material. The purpose of the study was twofold: first, to systematically analyze the forms by way of Fourier transform infrared (FTIR) spectrometry to fill a gap in chemical information that exits for coalified trigonocarpalean ovules of Carboniferous seed ferns; second, to use principal component analysis to focus on groupings as a function of chemical structure (functional groups) and to assess the different fossil forms in terms of FTIR chemical parameters, based on a 8 × 49 data matrix.Results include distinction among the three coaly sample forms, coalified layer (i), cupric + vitrain (iii) and cupric (v), based mainly, but not exclusively, on differences in carbonyl content, as well as length and branching of the polymethylenic chains. Important to note is the high aliphatic content of the cuticles as a signature of the biomacromolecules cutan/cutin. In particular, new insights into the structure of the original ovule are presented, and differences in chemistry are mainly a result of the complex structure of the precursor plant organ.  相似文献   

4.
The recently discovered lateritic nickel ore deposit on the summit area of the Tagaung Taung contains about 40 million DMT nickel-saprolite ore with approximately 2% Ni. The serpentinite massif is covered with a thick weathering mantle consisting of saprolite, limonite, and an allochthonous lateritic surface layer. The thickness, nickel content, and physical properties of the ore are very variable. The main minerals in the nickel saprolite ore are nickeliferous serpentine and smectite. Microprobe analyses show a strong depletion of Mg with increasing nickel content in the serpentine minerals; smectite generally contains less nickel than serpentine. Chemical analyses of samples from more than 100 drill holes are used to calculate the mean chemical compositions, mean accumulation factors, and gain and loss of major and trace elements for the various layers. This permits a quantitative approach to be made to the genetic history of the weathering mantle. Gain and loss determinations on the basis of constant chromium content and of constant volume give nearly identical results for the saprolite layer. Calculations on the basis of Ni/Cr ratios indicate that three-quarters of a former 20-m-thick limonite layer has been eroded away. Only the lower part of the original limonite layer with a relatively high SiO2 content is preserved. The kaolinite- and illite-rich surface layer is a mixture of limonite and weathered clayey material, which was probably derived from adjacent rocks. Part of the autochthonous weathering section is contaminated with infiltrated allochthonous surface material. It is not possible that colluvial-alluvial deposition of clayey material from nonultramafic rocks could have taken place under the present geomorphic regime. Thus, lateritization of the serpentinite and deposition of siallitic material must have occurred before exposure of the Tagaung Taung in its present form.  相似文献   

5.
Detailed trace-element analyses of pure magnetite from four continuous borehole intersections through the main magnetitite layer from the upper zone of the Rustenburg Layered Suite of the Bushveld Complex are presented. One section has been analysed at one centimetre intervals. Rapid depletion of Cr occurs over short, vertical sequences near the base of the layer, which is due to bottom-crystallization and the resulting chemical depletion of a thin layer of liquid. Sudden increases in Cr content of magnetite are attributed to convection cells which bring undepleted magma into the zone or crystallization. We suggest that these cells individually have lateral extents no greater than hundreds of metres, but collectively may be traced at a specific stratigraphic horizon for several tens of km. This lateral traceability of the effect of convection cells at approximately uniform stratigraphic height demonstrates the long-held implicit assumption that time-planes are in general parallel to the layering, and does not support the hypothesis that layers in the Bushveld Complex grew laterally. The activity of these cells is highly variable, with long periods of quiescence interspersed with periods of rapid, small-scale overturn. Most convection cells do not impinge upon the floor, and the abruptness of the resulting chemical reversal is largely a function of the thickness of the layer of depleted liquid trapped between the cumulates and the sole of the convection cell. Occasionally, these cells do touch the cumulate pile and may even cause erosion. This material may be redeposited elsewhere in the magnetitite layer either as mineralogically distinct fragments if erosion penetrated below the layer or, in the present instance, as a chemically chaotic pile of magnetite. The abruptness of the chemical reversals severely restricts the extent to which post-cumulus redistribution of elements or re-equilibration with percolating trapped liquid (infiltration metasomatism) may have occurred. The appearance of disseminated plagioclase in magnetite layers in variable proportions and in a non-systematic manner in the four profiles is attributed to fluctuations in pressure.  相似文献   

6.
露天煤矿生态地质环境系统恢复过程中,排于地表的不同年代地质层组的岩土剥离物都有可能成为复垦土壤母质。为科学合理利用矿区岩土剥离物,重构高质量复垦土壤,并指导后期分类排放,以平朔露天矿区黄土母质作为对照,评价不同类型岩土理化性状差异,从复垦土壤母质来源进行造地的源头控制,为露天煤矿土地复垦与生态修复提供依据。结合单项养分含量及有益微量元素含量分析结果,借助修正的内梅罗综合指数法,评价各岩土层肥力质量;借助单因子质量指数法,评价各岩土层环境质量。结果表明:各岩土层综合肥力系数位于0.40～1.26范围内,属贫瘠或一般水平;安家岭矿中2个煤矸石层的有机质或全氮含量、上部页岩层的全钾含量,以及东露天矿中炭质泥岩层的全磷含量丰富,显著高于黄土母质层;东露天矿底部细砂岩层及安家岭矿中泥灰岩层硫含量过高;东露天矿镉元素环境质量指数为1.05,属轻微污染等级;安家岭矿底部细砂岩层pH值低至4.25,酸度过大。平朔露天矿大多岩土层环境质量较好,但综合肥力质量较差,其中单项养分含量丰富,环境质量安全且易于风化的岩土层,适宜作为重构复垦土壤的备选材料。  相似文献   

7.
高岭土的深加工与新材料   总被引：6，自引：1，他引：6  
刘研  李宪洲 《世界地质》2004,23(2):195-200
煅烧高岭土由于晶体结构的改变而引起理化性能的变化，所表现出的性能更加优异。利用高岭土的特殊层状结构，将一些强极性有机小分子插入到结构层间，生成有机插层材料，这种新的复合物将黏土矿物和有机化合物的各自特性有机结合，极大地开阔了高岭土的应用领域和“档次”。以高岭土为原料而开发成功的Sialon材料，由于所具备的优越的力学性能、高温性能及化学稳定性等，在冶金、航空、化工机械和药学等方面显现出了极好的应用前景。地聚物材料是以偏高岭土、碱激发剂为主要原料，具有与陶瓷性能相似的一种新材料。  相似文献   

8.
This paper reports the results of a geochemical study of suspended particulate matter and particle fluxes in the Norwegian Sea above the Bear Island slope. The concentrations of suspended particles and the main components of suspended matter were determined in the euphotic, intermediate (“clean water”), and bottom nepheloid layers. It was shown that biogenic components are predominant in the water above the nepheloid layer, whereas the suspended matter of the nepheloid layer is formed by the resuspension of the lithogenic components of bottom sediments. The chemical compositions of suspended matter and material collected in sediment traps are identical.  相似文献   

9.
在核幔界面之上的下地幔一侧,地震波速分布极不均匀,厚度在50~300 km范围内变化的一层物质称为地幔底层。地幔底层由具有高地震波速和高密度的D″区和超低速带(ULVZ)组成。地幔底层是地核热能向地幔传播的必经之路,也是地幔中温度和温度梯度最高的地区。地幔底层既是俯冲板块的最终归宿,又是热柱和超级热柱的源区。因此,地幔底层既是全地幔对流的起点,又是全地幔对流的终点。在地幔底层可能发生地幔物质(包括俯冲板块物质在内)的部分熔融作用,也可能存在外核液态铁与地幔硅酸盐的化学反应。所以地幔底层在全球物质演化中占有重要的地位。  相似文献   

10.
Abundances of chemical elements in the Earth’s crust   总被引：1，自引：0，他引：1  
The evaluation of the abundances of chemical elements in the Earth’s crust is a pivotal geochemical problem. Its first solutions in the early 20th century formed the empirical groundwork for geochemistry and justified concepts about the unity of the material of the Universe, the genesis of the chemical elements, and the geochemical differentiation of the Earth. The accumulation of newly obtained data called for the revision of this problem, and a series of papers by A.P. Vinogradov, which were published in Geokhimiya in 1956–1962, presented reevaluated contents of elements in the continental crust. In these papers, A.P. Vinogradov relied on the classic idea of the geochemical balance of the sedimentary process. These generalizations provided the foundation for the quantitative characterization of the geochemical background of the biosphere and allowed Vinogradov to formulate the principles of the melting and degassing of material in the outer Earth’s shells during the geologic history, a concept that became universally acknowledged in modern geochemistry and geology. The composition of the Earth’s crust can also be evaluated based not on the principle of geochemical balance in the sedimentary process but on data on the actual abundances of major magmatic, metamorphic, and sedimentary rock types. The possibility of this solution was provided after the extensive research of A.B. Ronov, who managed to develop a quantitative model for the structure of the Earth’s sedimentary shell. Based on these data, A.B. Ronov, A.A. Yaroshevsky, and A.A. Migdisov published a series of papers in Geokhimiya in 1967–1985 that presented a model for the chemical structure of the Earth’s crust with regard for the material composing not only the upper part of the continental crust but also its deep-seated granulite-basite layer and the oceanic crust. The quantitative estimates thus obtained led the authors to important conclusions: first, it was demonstrated that the estimated abundances of elements in the granite-metamorphic layer of the continental crust presented in the classic works by A.P. Vinogradov are confirmed by independent materials, which are based on data on the actual abundance of rocks. Second, incredible as it was, the principle of geochemical balance in the sedimentary process in application to Ca and carbonates appeared to be invalid. This problem remains unsettled as of yet and awaits its resolution.  相似文献   

11.
This paper presents a theoretical study and a method regarding the separation of small nonferrous particles (Au, Ag) in low concentration from mineral wastes, using the dielectrophoresis phenomenon. The main theoretical considerations referring to the dielectrophoresis and the appearance and action of the electric gradient forces, typical for nonuniform fields, are presented. The gradient and superficial electric forces, in competition with gravitational forces, act on the dielectric particles from the surface of the material subjected to the separation process. Under the combined actions of all these forces, the metallic particles are concentrated on the surface of the mixture, forming a superficial conductive layer. Finally, the experimental results and conclusions regarding the concentrations in Au and Ag of the particles collected from the formed layer are presented, based on chemical analysis.  相似文献   

12.
Huret, C., Cojean, R. and Deveughéle, M., 1988. Temperature effects on engineering properties of loess: application to a loess of the Parisian Basin from 5°C to 80°C. Eng. Geol., 25: 209–228.

We present here an experimental work about the engineering behaviour of a calcareous loess from the Parisian Basin, the Rungis loess, in a temperature range of 5°C and 80°C. Mechanical testings on a collapsed and remolded material were realized with a specific apparatus. It allows us to give a stress and temperature history to the material while the process remains simple.

The temperature speeds up primary consolidation which is attained five times quicker at 80°C than at 20°C. The viscous flow of the skeleton and the compressibility are also increased in the same range. The consolidation phenomenon is theoretically analysed using both the classical Terzaghi approach and a rate process theory. The volume variations induced by a modification of the sample temperature is analysed and each phenomenon (thermic dilation, double layer modification, granular rearrangement) is emphasized.

All along this work, we have evaluated the specific characteristics of the loess: granularity, geochemistry, physico—chemical forces and structure. We emphasized the study of the microstructure of the material using pore size distribution measures by mercury intrusion and scanning electron microscopy. This permits us to relate the mechanical behaviour of the material to its micro-structure and to the pysico—chemical properties of the particles.  相似文献   


13.
金云母—蛭石间层矿物分晶层晶体化学式的计算及意义   总被引：10，自引：0，他引：10  
刘福生  彭同江 《岩石学报》2002,18(2):238-246
金云母－蛭石间层矿物由金云母晶层与蛭石晶层交叠排列而成，采用一般计算方法得出的晶体化学式不能充分揭示结构中金云母晶层与蛭石晶层各自的晶体化学特征。本文以化学成分分析与阳离子容量为基础，假定可交换性阳离子均为蛭石晶层层间阳离子，非交换性阳离子为金云母晶层层间阳离子，金云母晶层与蛭石晶层具有相同的八面体层等，计算出了结构中两种晶层的分晶层晶体化学式，确定了结构中两种晶层的比例和蛭石晶层的电荷数。并在此基础上讨论了新疆尉犁蛭石矿金云母－蛭石间层矿物的晶体化学特征。结果表明该方法设计合理，符合晶体化学原理，所计算的数据可靠。利用该方法计算出的两种晶层的比例为金云母－蛭石1：1规则间层矿物的确定提供了必要的依据。也为其它类似间层矿物的研究提供了一种计算分晶层晶体化学式的可行方法。  相似文献   

14.
有机累托石的合成与特性研究   总被引：7，自引：0，他引：7  
陈济美 《矿物学报》1991,11(1):86-91
累托石是二八面体云母层与蒙脱石层1：1规间民支矿物，兼有云母和蒙脱三 某些特征。本文利用二甲基十八烷基羟乙基季铵盐与累托石进行阳离子交换反应合成有机累托石。并采用物理化学、X射线衍射、差热、热失重和红外吸收光谱等分析方法对它的特性进行了研究。经季铵盐复合处理后，累托放扣蒙脱石层间被有机阳离子覆盖，它的面网间距d001由原来的24.8°/A增至29.5°/A。累托石粘土亲水憎油性转变为憎水亲油性有机粘土后能在有机溶剂中膨胀和分散。它是一种有应用前景的新材料。  相似文献   

15.
Experiments demonstrate that fluid escape structures can be produced as a result of unstable fluidization behaviour where a lower base layer of granular material is inhibited from fluidizing by the presence of an overlying non-fluidizing top layer. Before the base layer can fluidize the weight of the overlying material must be balanced, and this is accomplished by base layer material pressing against the bottom surface of the confining top layer forming a static layer. This static layer allows the top layer to lift away from the base layer which is then free to fluidize. A water-filled crack forms below the static layer and, as this grows, instability causes the static layer and top layer to bend and conical voids to form below the antiformal sections. Rupture occurs at the apex of the water void, allowing the underlying water and fluidizing material to burst out through the top layer. The fluidized base layer material then flows through the rupture until all of this material, except that in the static layer, is deposited above the previously overlying layer and a stable fluidization system results. The top layer material is bent upwards around the rupture, and the resulting pillar-type escape structure is preserved if flow then ceases. The vigour of the burst-out is greatest when the base layer material has a grain size 15% of the top layer material. If the base layer grain size is less than 8% of the top layer then base layer material will pass through the top layer pore spaces, without forming an escape structure. If cohesive material is present, escape structures form when a layer of fine grained cohesive material overlies a layer of cohesionless material. At low flow rates small pipes with scattered angular bends pierce the top layer, and base layer material passes through them. The base layer material is ejected on to the top layer and builds up around the mouth of each pipe to form constructional structures, sand volcanoes. This is in contrast to the cohesionless experiments, where the weight of material being deposited on the top layer caused an ejecta-filled depression to form around the rupture. If flow then ceases both the pipes and the sand volcanoes are preserved. At high flow rates, where the base layer fluidizes, the top cohesive layer becomes fragmented. Small fragments circulate within the fluidizing base layer and are preserved as floating clasts. Large fragments sink to the bottom of the fluidizing base layer. Erosion of the bottom surface of these larger fragments causes this surface to become convex downward. The experimentally derived structures are similar to pillar-type structures observed in the field and the processes described can be used to investigate the development of these structures. Fluidization experiments also demonstrate the genesis of dish structures, and the cohesive behaviour can be applied to the deformation of these structures after initial formation.  相似文献   

16.
This communication reports the occurrence of an ash layer intercalated within the late Quaternary alluvial succession of the Madhumati River, a tributary of the lower Narmada River. Petrographic, morphological and chemical details of glass shards and pumice fragments have formed the basis of this study. The ash has been correlated with the Youngest Toba Tuff. The finding of ash layer interbedded in Quaternary alluvial sequences of western Indian continental margin is significant, as ash being datable material, a near precise time-controlled stratigraphy can be interpreted for the Quaternary sediments of western India. The distant volcanic source of this ash requires a fresh re-assessment of ash volume and palaeoclimatic interpretations.  相似文献   

17.
Biominerals are natural composite materials comprising organic and inorganic components. Detailed knowledge of the nature and distribution of both components is a crucial requirement in order to advance our understanding of biomineral formation, their material properties and preservation potential as well as the interpretation of environmental data. Detailed chemical data are essential for our understanding of the nature and distribution of such components. Micro-XANES mapping at the sulphur K-edge reveals that, in the brachiopod Terebratulina retusa, the sulphate concentration is higher in the outer (primary) layer than in the calcite fibres of the secondary layer. This is co-incident with a higher magnesium concentration. In contrast, the sheaths surrounding the calcite fibres contain sulphur as thiol, confirming the presence of protein while, the sulphur within the fibres themselves, occurs as sulphate. Micro-XANES analysis of the insoluble organic extract from T. retusa indicates the presence of organic sulphate while Micro-Raman spectroscopy confirms that structurally substituted sulphate (SSS) is also present although semi-quantitative Raman spectroscopy carried out in this spectral region (wavenumbers 900–1200) indicates that the sulphate present is at the threshold of detection by Raman spectroscopy. The distribution of phosphorus in the shell of T. retusa correlates well with that of protein indicating the presence of phosphorylated proteins in the periostracum, the sheaths surrounding the calcite fibres and the interface between the primary and secondary layer.  相似文献   

18.
Thermochemical plumes develop at the core-mantle boundary in the presence of a heat flow from the outer core and at local chemical doping that decreases the melting temperature near the bottom of the lower mantle (this dope triggers the melting of the mantle material and the ascent of the plume). The paper presents evaluations for the heat power of the Hawaiian and Iceland plumes and the results of the experimental modeling of a thermochemical plume. The diameter of a plume conduit was determined to remain virtually unchanging in the course of plume ascent. When the top of a plume reaches a “refractory” layer, whose melting temperature is higher than the melt temperature in the plume conduit, a mushroom-shaped head of the plume develops beneath the bottom of this layer. The analysis of geological and geophysical data and the results of experimental modeling are used to develop a thermal physical model for a thermochemical plume. The balance relations for the mass and thermal energy and systematic tendencies in the heat and mass transfer during free convection were utilized to derive a system of equations for the heat and mass transfer of a thermochemical plume. Parameters were determined for a thermochemical plume ascending from the core-mantle boundary. Geodynamic processes are considered that occur during the ascent of a plume before it reaches the surface. The effect of the P-T conditions on the shape and size of a plume roof is analyzed, and a model is proposed for mass transfer between a thermochemical plume and the lithosphere, when the plume reaches the bottom of a “refractory” layer in the lithosphere.  相似文献   

19.
The infinitesimal and finite stages of folding in nonlinear viscous material with a layer-parallel anisotropy were investigated using numerical and analytical methods. Anisotropy was found to have a first-order effect on growth rate and wavelength selection, and these effects are already important for anisotropy values (normal viscosity/shear viscosity) < 10. The effect of anisotropy must therefore be considered when deducing viscosity contrasts from wavelength to thickness ratios of natural folds. Growth rates of single layer folds were found to increase and subsequently decrease during progressive deformation. This is due to interference between the single layer folds and chevron folds that form in the matrix as a result of instability caused by the anisotropic material behaviour. The wavelength of the chevron folds in the matrix is determined by the wavelength of the folded single layer, which can explain the high wavelength to thickness ratios that are sometimes found in multilayer sequences. Numerical models including anisotropic material properties allow the behaviour of multilayer sequences to be investigated without the need for resolution on the scale of individual layers. This is particularly important for large-scale models of layered lithosphere.  相似文献   

20.
鄂尔多斯盆地JX井延长组砂岩固碳潜力分析   总被引：1，自引：1，他引：0  
神华集团在我国CO2地下埋藏的潜在目标区(鄂尔多斯盆地)实施的CO2注入工程仍存在有关其注入层之上泥岩盖层安全性方面的争议.通过对与神华集团CO2注入井相邻且钻遇地层系统、岩石组合一致的JX井三叠系延长组(位于注入层之上)的研究预测一旦CO2透过盖层后的再续固碳能力.研究层位岩屑样品类型主要为长石砂岩和岩屑长石砂岩,其次为岩屑砂岩和岩屑石英砂岩;其物源区岩石类型主要为长英质火山岩、其次为中性火山岩及少量富含石英的沉积岩,具中性斜长岩成分特征;其上段(466~534 m)及下段(666~958 m)砂岩母岩受到弱-中等化学蚀变,并可能经历了再旋回过程;中段(534~666 m)砂岩母岩未受化学蚀变影响,并可能为第一次旋回沉积物.作为潜在的CO2再续固碳场所,延长组砂岩具有实现CO2矿物圈闭的物质条件及形成片钠铝石、方解石、铁白云石和菱铁矿等固碳矿物的潜力.  相似文献   

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