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1.
RS和GIS技术集成及其应用 总被引：13，自引：3，他引：10
何庆成 《水文地质工程地质》2000,27(2):44-46
本文简要地介绍了ＲＳ（遥感图像处理系统）和ＧＩＳ（地理信息系统）技术及其集成的基本概念和方法。讨论了ＲＳ和ＧＩＳ技术及其集成的内在涵义、相互关系,认为ＲＳ是ＧＩＳ重要的外部信息源,是其数据更新的重要手段,尤其对于全球性的 地理动力学分析,更必须有ＲＳ所提供的覆盖全球的动态数据与ＧＩＳ的结合。反之,ＧＩＳ则可以提供ＲＳ所需要的一些辅助数据,以提高ＲＳ图像的信息量和分辨率,同时,ＧＩＳ可以将实地调查所 相似文献
2.
在分析和总结前人对红藻石和蓝藻石研究成果基础上,结合岩石薄片显微镜下观察实例,发现在以往碳酸盐岩颗粒分类中没有红藻石和蓝藻石的合适位置。鉴于红藻石重要的成因意义和造礁作用,有必要明确红藻石的概念和归属。珊瑚藻本身极易钙化,经生物矿化作用最终保存下来的珊瑚藻屑一直放在生物碎屑中,而红藻石是由非固着的珊瑚藻构成的钙质独立结核,因此也可以被划分到生物碎屑中。蓝藻石作为蓝细菌钙化作用的产物,同时鉴于蓝藻石的广泛存在,把钙化蓝细菌形成的核形石命名为蓝藻石,这一重要概念从提出到现在一直被使用。然而蓝绿藻概念已变更为蓝细菌,蓝藻石的形成与藻类无关,显然将其称作蓝菌石更加确切。因此,应将红藻石和蓝藻石分别归为生物碎屑和核形石当中,并用新的术语蓝菌石替代蓝藻石。其意义在于使红藻石和蓝藻石的概念及归属更为规范,并为碳酸盐岩颗粒的深入研究提供有益线索。 相似文献
3.
Morgan D. Thomas 《Geoforum》1981,12(1):1-17
Regional economic development is largely influenced by technical progress, and innovative manufacturing firms are important in this context. Large, fast growing, innovative firms contribute significantly to growth by direct and indirect employment and income-generating impacts, and these are likely to be extended through time if the firms are capable of developing new product lines and markets. Unfortunately, ‘orthodox’ theories of the firm provide a poor basis for understanding ‘how’ and ‘why’ innovative firms come into existence, grow, change, and operate over time and geographic space. Behavioral—managerial notions, on the other hand, do appear to provide a useful basis for conceptualization. This paper examines some of these concepts and goes on to provide a framework for understanding growth and change in innovative, multiproduct, multiregional firms. 相似文献
4.
毫米波测云雷达的特点及其研究现状与展望 总被引：17，自引：2，他引：15
云在大气的能量分配、辐射传输,尤其是水循环系统中有不可忽视的作用。云探测对云物理、人工影响天气、气候变化和航空航天等领域有重要意义,是大气科学研究的热点之一。尽管目前已经发展了很多种遥感设备对云进行观测(如激光雷达、卫星、云幂仪等),但这些设备无法得到高时空分辨率的云水平和垂直结构,而毫米波雷达是云三维精细结构探测的重要工具。由于毫米波雷达具有更接近小粒子尺度的短波长,因此更适合用来探测弱云,同时毫米波雷达也存在衰减严重的缺点。介绍了毫米波雷达的特点以及其探测小粒子的优势;对比分析了其与新一代多普勒天气雷达、晴空风廓线雷达的差异,得出：毫米波雷达具有高时空分辨率,能够更精确地反映云的垂直和水平结构,比普通天气雷达更适合监测云的变化。概括了国内外毫米波测云雷达的发展现状以及在云物理研究方面的情况,并展望了国内毫米波雷达未来研究的方向。 相似文献
5.
定量的砂岩（砂）岩相学分析是重要的岩石学分析手段,有助于探讨沉积物的源区、背景和沉积盆地性质.在过去几十年中,科学家们对于砂岩（砂）的定量碎屑颗粒统计及其潜在地质意义（如沉积碎屑物与源区母岩的关系、沉积过程对碎屑组分的影响、碎屑组分与大地构造背景的关系等）取得了很多进展,但是对于定量的岩相分析方法和命名方案一直缺少系统的总结,导致一些实际工作中的波折和误区.在总结前人文献的基础上,系统描述了砂岩（砂）定量岩相分析的方法,并推荐最优的分类命名方案,希望建立统一的工作规范,本文提升砂岩（砂）碎屑颗粒统计结果的可靠性和数据的可对比性.同时,我们对砂岩构造背景判别图解的适用性进行了探讨,认为图解是展示砂岩碎屑组分统计结果的有效工具,但用于构造背景判断时则需谨慎,最好基于岩石本身的特征并结合其他资料综合探讨. 相似文献
6.
Uzo M. Igbozurike Dr. 《GeoJournal》1978,2(5):443-449
Although polyculture or interplanting is a dominant production method used by traditional cultivators in the tropics, there has been increasing emphasis on monoculture in agricultural development planning. Analysis of the economic and ecological consequences of these two cropping alternatives in a densely-populated area of eastern Nigeria suggests that a focus on monoculture as a panacea for increasing productivity and food supply is questionable. Polyculture is held to be ecologically superior to monoculture and, in the field area examined, economically more productive as well. Thus further investigation of polycultural approaches to agricultural development would appear to be warranted. 相似文献
7.
Katy A. Boon Paul D. Taylor Michael H. Ramsey 《Geostandards and Geoanalytical Research》2007,31(3):237-249
Measurements taken to characterise environmental contamination contain uncertainty, which is generated by both field sampling and chemical analyses. Recently devised techniques have been applied for the first time to estimate this uncertainty in the commercial monitoring and assessment of contaminated land. The uncertainty reduces the reliability of the classification of the land that is made following a site investigation. The possible misclassification of areas of land, as a result of measurement uncertainty, can lead to substantial financial penalties, resulting from litigation or unnecessary remediation. Previous studies have developed methods for the estimation and financial optimisation of measurement uncertainty. These methods have now been applied to a series of six contrasting site investigations, which were conducted by various commercial organisations. The previous uses of these sites included a gas works, a tin mine and railway sidings. The measurement uncertainty was successfully estimated for each of the six investigations, showing its applicability to a wide range of different sampling methods, such as trial pits, window sampling and augering. The measurement uncertainty ranged widely between sites from 25% to 158%, indicating that investigations can differ widely in their reliability. The field sampling tended to generate the largest component of the measurement uncertainty when compared to the contribution from the chemical analysis. The Optimised Contaminated Land Investigation (OCLI) method was applied to each site, with the initial aim of estimating the financial losses that could be incurred as a result of misclassifying the land, due to the uncertainty. It showed that the expectation of loss value per sampling location ranged from only £58 at one site to over £ 11 000 at another. The optimal level of uncertainty that produced the minimal financial loss was then calculated for each site. It provided a reduction in the expectation of loss for the whole site of over £ 10 000 at two of the sites and over £90 000 at two others. These findings demonstrate that implementing concepts of uncertainty can have practical benefits in environmental monitoring, and can enable improvements to be made in the quality of sampling and hence of measurements in general. 相似文献
8.
Radan Květ 《GeoJournal》1990,22(4):387-390
Conclusion The suggested application of hierarchical systems to geology and geography offers a new view on the evolution of the Earth and a new classification of geosciences. The application of these systems allows the individual fields of geosciences to be connected with each other and also with other disciplines (e.g. physics, astronomy, biology). Hierarchical systems including periodicity can aid future advances in natural sciences because they can be regarded as a uniting principle and key to new approaches to research in natural sciences. 相似文献
9.
铀钍的地球化学及对地壳演化和生物进化的影响 总被引：10，自引：2，他引：8
本文论述了在含挥发份和贫挥发份条件下Ｕ、Ｔｈ的迁移行为及其对地球和行星演化的影响,并阐述了造成地球独特地质演化历史的原因。提出了Ｕ、Ｔｈ在地球中的迁移模式以及该模式对地壳形成、演化的控制作用和对生物发展演化的可能影响。 相似文献
10.
Transient and spatial modeling and simulation of polybrominated diphenyl ethers reaction and transport in air, water and soil 总被引：1，自引：0，他引：1
M. Mousavi Ph.D. S. Kiani S. Lotfi N. Naeemi M. Honarmand 《International Journal of Environmental Science and Technology》2008,5(3):323-330
The release of the wastes containing polybrominated diphenyl ethers into the environment is a worldwide major concern. Investigation of spatial and temporal variations of polybrominated diphenyl ethers concentrations due to different factors, especially the transport of these species between air and water as well as between air and soil is the purpose of present research. A model was developed and solved using the methods of finite difference and lines. Simulations were implemented for three dimensions of width, length, and height and also time for the air compartment, whereas for the soil and water compartments, variations were considered only with respect to height and time. Transport between water and soil was disregarded for simplicity at this stage. Vancouver’s landfill was considered as a case study. Lower concentrations in air and higher concentrations in water at the interface show that these pollutants tend to diffuse from air to water. Concentrations of all four pollutants decrease near the interface in soil as time passes, but they are predicted to be almost constant at other levels. 相似文献
11.
Garnet-peridotite stability and occurrence in crust and mantle 总被引：10，自引：0，他引：10
The boundary between the spinel- and garnet-lherzolite mineral facies is strongly curved between 1300° C and 1450° C; below 1200° C it lies almost parallel to the temperature axis of the T-P diagram.Pressure of at least 12 kb is required to stabilise garnet-peridotite on the geothermal gradient and the depth at which the boundary is encountered is not sensitive to variations in the geotherm.Garnet-peridotite is metastable with respect to spinel-peridotite in normal continental crust. Natural occurrences are mantle derived and have either suffered rapid upward transit in diatremes or, in orogenic zones, either they were emplaced after upward tectonic transport through tens of kilometres, or have originated by in situ metamorphism of pre-existing crustal peridotite in an orogenic root downfolded to depths of at least 40 km. 相似文献
12.
Cumulate and Cumulative Granites and Associated Rocks 总被引：1，自引：0，他引：1
Abstract. Processes that move crystals relative to melt, that is crystal fractionation, are of major importance in producing variations that are observed within cogenetic suites of granites. In low‐temperature granite suites, crystal fractionation initially involves the progressive separation of crystals residual from partial melting from that partial melt. Once separation of those crystals, or restite, has been completed, further fractionation may occur through the separation of crystals that had precipitated from the melt, the process known as fractional crystallization. High‐temperature granite magmas are largely or completely molten and elements such as Ca, Mg and Fe, and their associated minor elements, are in that case dissolved in the melt. Such magmas, particularly those that are more potassic and hence contain a higher fraction of low temperature melt, may evolve compositionally through fractional crystallization. Cumulate rocks result, comprising a framework of cumulus minerals with interstitial melt. In this process some of the melt is also displaced to form more felsic rocks. Such cumulate rocks may have distinctive chemical compositions, but that is often not the case. Distinctive features include SiC>2 contents near or below 50 % in rocks that are transitional in the field to more felsic granites, very high Cr and Ni, very low K, P, Ba, Rb and Zr, and anomalous abundances of the anorthite components Ca and Al. These rocks may also have positive Eu anomalies. Cumulate rocks do not necessarily have distinctive textures, at least as such features are understood at this time. Fractional crystallization can also involve the movement of precipitated crystals relative to melt. We refer to rocks as cumulative when formed from the fractions in which the abundance of crystals has increased. The production of cumulative granites typically occurs at more felsic melt compositions than is the case for cumulate granites, and this process may have its greatest significance in the fractional crystallization of the felsic haplogranites. Relative to felsic granites of broadly similar compositions lying on a liquid line of descent, cumulative granites contain more Ca, reflecting the addition from elsewhere of plagioclase crystals with solidus compositions. The abundances of Sr and Ba may be high to very high, and sometimes there are positive Eu anomalies. Cumulative I‐type granites may have low abundances of Y and the heavy REE, while the S‐type granites can be very distinctive with anomalously high abundances of Th and the heavy REE resulting from the concentrating of monazite. Generally, but not always, those who propose fractional crystallization as a mechanism for producing compositional variation within a suite of granites do not state whether the rocks in that particular case are thought to lie on a liquid line of descent or are cumulates/cumulative, although it is generally presumed that they were melts. Our experiences in eastern Australia have shown that the mechanism of fractional crystallization was quantitatively not as important during granite evolution as many workers would expect. However, there are some excellent examples of that process, most notably the Boggy Plain Supersuite. Overall in eastern Australia, varying degrees of separation of restite is a much more common mode of crystal fractionation, and that may also be seen to be the case for some other granite provinces if they are examined with that possibility in mind. 相似文献
13.
Results of numerical analyses of boundary value problems in geomechanics include output of three‐dimensional stress and strain states. Two‐dimensional plots of stress–stress or stress–strain quantities, often used to represent such output, do not fully communicate the evolution of stress and strain states. This paper describes the use of glyphs and hyperstreamlines for the visual representation of three dimensional stress and strain tensors in geomechanics applications. Glyphs can be used to represent principal stress states as well as normal stresses at a point. The application of these glyphs is extended in this paper to represent strain states. The paper introduces a new glyph, called HWY glyph for the representation of shear tensor components. A load step‐based hyperstreamline is developed to show the evolution of a stress or strain tensor under a general state of loading. The evolution of stress–strain states from simulated laboratory tests and a general boundary value problem of a deep braced excavation are represented using these advanced visual techniques. These visual representations facilitate the understanding of complex multidimensional stress–strain soil constitutive relationships. The visual objects introduced in this paper can be applied to stress and strain tensors from general boundary value problems. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
14.
《International Geology Review》2012,54(5):526-533
The impact of gigantic meteorites momentarily creates extremely high pressures and temperatures, leading to the formation of distinctive objects — impact breccias and impactites — at the points where they fall. The Zhamanshin crater is one such place. This annular structure has a diameter of about 10 km, contoured by a low rim made up of a body of shattered Paleozoic rocks thrown out from the ring's center, from depths exceeding 100 - 200 m. Among these breccias have been found pieces and lenticular bodies of remelted rocks — impactites, called zhamanshinites. These thermally altered rocks from a series ranging from baked clays to cinder-like, partly recrystallized substances, glass, and black drops and spattered droplets (up to 1 - 5 cm) of isotropic glass that undoubtedly hardened as they fell through the air. The refused neogenic substances formed by selective evaporation are characterized by a considerable deficit of K and Na, excess Al2O3 and SiO2, a lack of H2O, and a sharp predominance of Fe+2 over Fe+3. Their characteristic shape and distinctive structure and composition suggests that these remelted droplets are tektites, which were called irgizites when first found in the USSR. Their occurrence in the meteorite crater confirms the idea of a genetic unity between tektites and impactites. Selective evaporation of the more volatile elements is characteristic of the surfaces of small planets lacking an atmosphere, but is not characteristic of the earth's surface. The processes and substances occurring at the impact points of gigantic meteorites are therefore unique on the earth, but highly typical of the surfaces of the Moon, Mars, Mercury, and other relatively small celestial bodies. 相似文献
15.
Douglas G. Pearce 《GeoJournal》1989,19(3):257-262
This paper reviews the interfaces between international and domestic tourism and explores a number of associated issues. Within the origin the interface is between domestic tourism and the outbound component of international tourism. Questions arise relating to the different propensities for domestic and outbound travel and reasons accounting for this variation at a national scale — size, national tourist resources and levels of economic development — and at an individual level where motivations and the ability to travel play a major role. Within destinations interfaces exist between domestic tourism and inbound international tourism. Questions there relate to the size and distribution of these two types of tourist traffic, their respective impacts and the interaction between the two groups. Issues raised include those of the substitution of domestic and outbound travel and the formulation of policies whose varied aims are likely to be met by different spatial strategies. Future research needs to examine differences and interactions between domestic and international tourism more fully and explicitly so that more effective policies might be derived. 相似文献
16.
《Applied Geochemistry》2005,20(2):367-381
Several series of saturated, diaromatic, triaromatic C-ring cleaved and triaromatic diterpenoids and triterpenoids have been detected in 4 immature coal and mudstone samples. A number of these compounds appear to represent intermediates in a series of postulated pathways for progressive aromatization of biogenic diterpenoids and triterpenoids. Diagenetic pathways for the formation of tricyclic aromatic hydrocarbons from abietane and pimarane type diterpenoid precursors and for the formation of diaromatic, triaromatic C-cleaved and triaromatic hydrocarbons from β-amyrin and other triterpenoid precursors are proposed. Saturated and aromatized abietanes, pimaranes and phyllocladanes, which are the most abundant compounds in all 4 samples, indicate a predominant higher plant input which can be related to the Coniferales group but not to individual plant families. β-Amyrin and other triterpenoid-derived triaromatic and triaromatic C-ring cleaved hydrocarbons with triterpenoid structures are thought to be characteristic for angiosperms. The relative concentrations of the triaromatic and triaromatic C-ring cleaved hydrocarbons are higher in samples 9602 (mudstone) and 9603 (coal) than samples 9601 (coal) and 9604 (mudstone) indicating samples 9602 (mudstone) and 9603 (coal) contain relatively more angiosperm derived organic matter than samples 9601 (coal) and 9604 (mudstone). The distribution patterns and the relative concentrations of saturated and aromatic diterpenoids and triterpenoids thus are valuable markers for the determination of the relative contents of biological sources of organic material in geological samples. 相似文献
17.
埃达克质岩与成矿:困惑与探索 总被引：3，自引：0，他引：3
根据起源于下地壳的中酸性岩浆岩的成分变化,可以约束其源区深度以及地壳最小厚度,为大陆板内成矿作用的深部过程研究提供重要信息。全球范围内,许多世界级斑岩铜矿和浅成热液矿化系统与同期的埃达克质岩存在密切的时空与成因联系,在国内主要成矿区带也识别出与金属成矿作用有关的埃达克(质)岩。与俯冲过程无关的埃达克质岩的识别,使我们有可能结合其他地质证据构建完全不同于Sillitoe(1972)B型俯冲环境的斑岩铜矿成矿模式的大陆板内斑岩(夕卡岩)型金属矿床成矿模式。对于规模巨大、矿质主要源自地幔的热液矿床的形成,埃达克(质)岩可能是必要条件,但不是充分条件。埃达克(质)岩的成矿潜力通过地幔物质加入而获取,埃达克(质)岩的成矿专属性由上地幔成矿元素分布特征决定。与俯冲有关的埃达克质岩浆之所以有利于成矿,重要的原因是存在大量来自俯冲板片的高压、高温流体以及俯冲板片熔融形成高氧逸度(fO2)的熔体,但产出在大陆板内背景、与俯冲无关的埃达克(质)岩的成矿机制还不清楚。根据现代资源勘查理念,结合综合地质信息分析,埃达克质岩具有实际找矿意义。 相似文献
18.
单颗粒矿物微量元素激光原位定量分析测试数据的大量积累和研究,使矿物成为矿床地球化学研究和矿床勘查的重要示踪剂。本文重点选择磁铁矿、磷灰石、石榴子石、榍石、锆石、绿泥石和绿帘石等的原位分析研究所获得的认识,介绍单颗粒矿物成分组合及变化在矿床类型划分、成矿年龄测定、氧逸度、成矿过程与物质来源、找矿与勘探等方面的应用。不同矿床类型中普遍存在的矿物,如磁铁矿、磷灰石等的微量元素含量及组合差异,提供了矿床类型识别的标志。单颗粒矿物,特别是矿石矿物和密切共生矿物如锡石、铌钽铁矿、赤铁矿、石榴子石、方解石等的原位定年,使成矿年龄的直接准确测定成为现实。矿物中变价元素,如Fe、V、Mn、Ce、Eu含量和/或比值的变化,指示了成矿过程氧逸度及其变化特点。从矿物核部向震荡环带与边部的微量元素含量或同位素组成的变化,示踪了成矿过程中流体来源或性质的变化。斑岩和矽卡岩矿床中与成矿作用关系密切的蚀变矿物,如绿泥石、绿帘石的形成温度、特征微量元素比值,如Ti/Sr、Ti/Co、V/Ni、Mg/Sr等,与距矿床中心距离呈线性函数关系,可定量预测距矿床中心的距离,使以绿泥石、绿帘石为代表的找矿指示矿物研究迅速发展。 相似文献
19.
Andrew H. Baldwin 《Estuaries and Coasts》2013,36(3):547-558
To test species composition and biomass responses to excess nutrients, herbaceous plants of tidal freshwater and oligohaline wetlands in a Chesapeake Bay subestuary were fertilized with nitrogen (N), phosphorus (P), both N and P (N?+?P), or not fertilized (Control) for 4 years. In marshes, the N treatment increased abundance measures of perennials but decreased those of annuals while the P treatment increased annuals and decreased perennials. In swamps, however, perennials increased in response to P. Total herbaceous aboveground biomass production was not limited by N, P, or N?+?P in marshes or swamps. These findings suggest that annual species are more susceptible than perennials to P limitation, possibly due to lack of a large perenniating root organ and lower susceptibility to mycorrhizal inoculation. Furthermore, eutrophication effects are likely to vary between swamp and marsh habitats and depend on whether the dominant nutrient supplied is nitrogen or phosphorus. 相似文献
20.
Concentrations of Ga and Ge in the metal of 31 L-, 8 LL- and 2 H-chondrites, and in the silicates of 12 L- and LL-chondrites have been determined by spectrophotometric methods. The ranges of Ga contents in the metal of L- and LL-chondrites are 1.1–36.9 ppm and 1.0–34.1 ppm, respectively. The Ge content in the metal is positively correlated with Ga and ranges from 89.1–160 ppm, and 126–308 ppm for L- and LL-chondrites, respectively. The Ga content in the silicates of L-chondrites varies from 4.0 to 8.9 ppm.The Ga and Ge contents in the metal are clearly lower in unequilibrated than in equilibrated L- and LL-group chondrites. Unequilibrated (type 3 and 4) and equilibrated (type 5 and 6) chondrites are well separated in the plots of Ga vs Ge in the metal and the L- and LL-groups are also well resolved. The Ga and Ge in the metal are well correlated with petrologic grade. This suggests that Ga and Ge variations in the metal are related to thermal metamorphism. There is evidence of an enrichment of Ga in the metal due to shock-reheating. 相似文献