Moscow, the global city? The position of the Russian capital within the European system of metropolitan areas   总被引：1，自引：0，他引：1  

Isolde Brade  Robert Rudolph 《Area》2004,36(1):69-80

During the 1990s, the city of Moscow was subject to an extraordinary transformation in its political, economic and social structures, which had consequences for the position of Moscow within the national and international hierarchy of cities. This article is concerned with the trends that can be discerned regarding the position of Moscow on the national and European scales. Without a doubt, the development of Moscow is characterized by an increasing separation from the national urban system and a growing international orientation. The Russian capital has no competitors on the national level: measured against the relevant economic indicators it is a long way ahead of the remaining Russian cities, which are primarily integrated into national and regional economic flows, and participate in the global economy only to a limited degree. Moscow, in contrast, is increasingly striving to integrate itself into transnational and international economic structures. Although the concept of Moscow as a global city is often instrumentalized in municipal politics, the ability of the Russian capital to act as a global centre is in fact limited. At present Moscow's most important function, from a Central European perspective, is to act as a bridging link between Central and Western Europe and Russia. There is a danger that the spatial disparities between Moscow on the one hand, and the remaining Russian cities and regions on the other, will continue to grow.  相似文献   

甘肃黄土台塬区农业过量灌溉引起的滑坡灾害   总被引：10，自引：0，他引：10  

王志荣  吴玮江  周自强 《中国地质灾害与防治学报》2004,15(3):43-46,54

黄土台塬区过量农业灌溉可引起严重的滑坡灾害。其中以甘肃省永靖县黑方台提灌区的滑坡灾害最为典型。黑方台黄土台塬自20世纪60年代开始农业提水灌溉，受其独特的地质地貌控制，在灌溉水大量入渗的诱发下，滑坡灾害十分严重。主要有黄土滑坡和黄土一基岩滑坡两种类型，分别具有高速远程和低速近程滑动的特点。过量灌溉引发的滑坡灾害具有滞后性、群发性和频发性等显著特征，且在季节分布上主要集中在冻融期(3月)和雨季(7月)。实践表明，对过量灌溉引发的滑坡灾害应以预防为主，治理为辅。改变灌溉方式和采取包括工程治理措施、排水措施、生物措施在内的综合治理措施是行之有效的防治措施。  相似文献   

岷江较场台地地震裂缝形成机制及其边坡稳定影响   总被引：2，自引：0，他引：2  

卫宏  王兰生 《中国地质灾害与防治学报》2004,15(4):17-19,24

岷江上游的大、小海子是两个相连的地震滑坡、崩塌堰塞湖。几十年来对湖泊东岸较场镇台地的认识不一，其岸坡稳定问题是利用该天然湖泊建设水电站的关键。通过现场调查与钻探、测试，发现岷江上游的较场台地是一个向岷江凸出的、1万a前形成的湖相沉积台地。1933年，在强烈地震作用下，较场台地发生了强烈裂陷，未发生大规模的滑移，在台地上形成了两组近于垂直的地裂缝。进一步研究表明，这两组地裂缝虽然是在同一诱发因素下，在同一时间、同一地点形成的，但它们的形成机制却不同。一组走向近SN，是在强烈地震作用下，追踪岩体中原有的两组构造节理进一步裂开的产物，可称为地震构造追踪型地裂缝；另一组走向近EW，是顺向边坡中的层状岩体，在地震作用下沿软弱层发生层间滑动，地面被拉开、沉陷而形成的，可称为地震层间滑动型地裂缝。两种类型的地裂缝与层面的空间组合，控制着台地的稳定与演化。特别是当遇到类似1933年那样的地震，甚至由于两种地震地裂缝与层间错动面的存在，不需要那么高强度的地震，就可能诱发大规模的边坡稳定问题。这应该引起天龙湖水电站与213国道等管理部门的重视。  相似文献   

扬子地块西南缘铅锌矿床Cd、Ge与Ga富集规律初步研究   总被引：7，自引：2，他引：7  

付绍洪  顾雪祥  王乾  李发源  章明 《矿物岩石地球化学通报》2004,23(2):105-108

扬子地块西南缘分布着大量富含Cd、Ge与Ga的铅锌矿床，已成为我国Pb、Zn及Cd、Ge与Ga矿产资源的重要生产基地。对代表性铅锌矿床进行野外地质调查和系统采样鉴定后．应用电子探针微区分析手段，研究主要矿石矿物闪锌矿、方铅矿和黄铁矿中分散元素的富集特征。结果显示．各类矿床中闪锌矿均相对富集Cd，方铅矿富集Ge与Ga，而黄铁矿中Cd、Ge与Ga的富集系数均相对较低．未呈现出选择性富集的趋势；赋存于震旦纪一寒武纪地层且以脉状、网脉状产出的矿体中闪锌矿的Cd含量明显高于赋存于晚古生代并以层状产出的矿体中闪锌矿的Cd含量。  相似文献   

The influence of rock resistance on coastal morphology around Lord Howe Island,southwest Pacific     

M. E. Dickson  D. M. Kennedy  C. D. Woodroffe 《地球表面变化过程与地形》2004,29(5):629-643

An Erratum has been published for this article in Earth Surface Processes and Landforms 27(7) 2004, 931. Lord Howe Island, in the northern Tasman Sea, is a remnant of a much larger Late Miocene basaltic shield volcano. Much of the island's coastline is exposed to waves that have unlimited fetch, but a marked contrast is provided by a fringing coral reef and lagoon that very effectively attenuate wave energy along a portion of the western coastline. The geology of the island is varied, with hard and resistant basalt lavas, breccias and tuffs of intermediate resistance, and highly erodible eolianites. This variability provides an excellent opportunity to examine the in?uence of rock resistance on the development of the spectacular rock coast landforms that occur around the island. The hardness of rocks and the extent of weathering around the coastline were assessed using a Schmidt hammer, and statistical analysis was undertaken to remove outlying values. On all but one occasion, higher mean rebound values were returned from fresh surfaces than weathered surfaces, but only half of these differences were statistically signi?cant. Shore platforms with two distinct levels are juxtaposed along two stretches of coastline and Schmidt hammer results lend support to hypotheses that the raised surfaces may be inherited features. Relative rock resistance was assessed through a combination of Schmidt hammer data and measurements of joint density, and constrained on the basis of morphological data. This approach formed a basis for examining threshold conditions for sea‐cliff erosion at Lord Howe Island in the context of the distribution of resistant plunging cliffs and erosional shore platforms. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

基于J2EE与ArcIMS的地图服务系统的设计   总被引：4，自引：0，他引：4  

万宝林 《国土资源信息化》2005,(6):35-37

随着Web技术的不断发展,WebGIS的实现方式也变得多样化。本文阐述了运用传统的、单一的ArcIMS技术构建WebGIS所存在的不足,并提出了运用ArcIMS与J2EE相结合,实现功能灵活的网上地图服务系统。  相似文献   

Shore platform morphology on a rapidly uplifting coast,Wellington, New Zealand     

D. M. Kennedy  J. G. Beban 《地球表面变化过程与地形》2005,30(7):823-832

The coast of Wellington, New Zealand, is tectonically active and contains a series of uplifted and contemporary shore platforms that are developed in Triassic Greywacke. The platform profiles are rugged with relief of metre scale common. The surveyed platforms were formed at, and at two distinct levels 1–1·5 and 2–2·5 m above, mean sea level. They range in width up to 70 m and are highly fractured with fracture densities in excess of 20[sol ]m² common. The rate of development of these platforms is rapid, with lateral erosion rates of up to 0·15 m[sol ]yr calculated, allowing platform development to occur over centennial scales. Even given this rapid development, continued instantaneous uplift of the coast has meant they are unable to reach an equilibrium state, whereby the effectiveness of wave processes in removing material is reduced by platform extension. The co‐seismic uplift means that the rear of the platforms is raised beyond the limits of marine process and has become an area of deposition. Although no direct process measurements were made the highly fractured nature of the bedrock appears to play a major role in platform evolution, with wave processes being easily able to pluck blocks as evidenced by fresh erosion scars and active gravel beaches at the rear of many platforms. This coast therefore represents an extremely dynamic youthful shore platform environment, where the processes of marine abrasion can be observed over historical timescales. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Research on the seismic fortification level of offshore platform in Bohai Sea and adjacent areas     

彭艳菊  吕悦军  唐荣余  沙海军 《地震学报(英文版)》2005,18(6):697-706

Introduction Offshore platform is the main facility for exploitation of ocean resources, e.g. oil and gas. Nearly 6 000 platforms have been built in the world, 100 among them in China, another 100 will be erected in China in the coming 5 years. The current aseismic design code commonly used in the world is RP2A-WSD based on the seismic hazard zone in the coastal waters of the United States, which is compiled by American Petroleum Institute (American Petroleum Institute, 2002). No specif…  相似文献   

Sediment production and dispersal on foraminifera-dominated early Tertiary ramps: the Eocene El Garia Formation, Tunisia   总被引：4，自引：0，他引：4  

SIMON J. BEAVINGTON-PENNEY†  V. PAUL WRIGHT†  ANDREW RACEY† 《Sedimentology》2005,52(3):537-569

Larger benthic foraminifera Nummulites are common within Eocene, circum-Tethyan limestones. Despite their importance as sediment producers, contradictions in the literature constrain current understanding about the location of the Nummulites‘factory’. The El Garia Fm was deposited on a ramp with localized palaeohighs, and whilst some authors suggested that the locus of Nummulites production was in shallow water across the palaeohighs, others concluded that production was significantly reduced over these palaeohighs, and concentrated in the surrounding deeper (30–60 m) water. There are also marked dissimilarities between recent models in terms of the continuity, correlation and resolution of depositional sequences. To assess these models, we integrate studies of the architecture and geometry of the El Garia Fm with detailed taphonomic, biometric, biofabric and palaeoecological characterization of Nummulites tests. We conclude that the highest rates of sediment production occurred in euphotic water over the palaeohighs and in nearshore environments. Nummulites on the palaeohighs were transported into the surrounding deeper water by oceanic and storm currents that swept the platform top, producing a nummulitic sediment package that thickened and became increasingly fine-grained and fragmented into outer ramp environments. This transport exerted a major control on development of the ramp-like geometries often seen at outcrop. Our findings question the validity of a recent sequence stratigraphic model that identifies decimetre-scale Milankovitch cycles, even in largely allochthonous, ‘bio-retextured’, mid/outer ramp sediments. Our findings also suggest that the thin packages of El Garia Fm on the palaeohighs, which have previously been interpreted as condensed sections that can be correlated with thicker, more distal accumulations, actually represent remnants of the sediment that was produced on the highs and ‘exported’ into the basin.  相似文献   

Facies, cycles, and controls on the evolution of a keep-up carbonate platform (Kimmeridgian, Swiss Jura)   总被引：2，自引：0，他引：2  

CLAUDE COLOMBIÉ  ANDRE STRASSER† 《Sedimentology》2005,52(6):1207-1227

During the Late Jurassic, accelerated ocean-floor spreading and associated sea-level rise were responsible for a worldwide transgression, which reached its maximum in the Late Kimmeridgian. In many Western European basins, this major sea-level rise led to the formation of marly and condensed sections. In the Swiss Jura, however, a shallow carbonate platform kept growing and only subtle changes in the stratigraphic record suggest an increasingly open-marine influence. Field observations and thin-section analyses reveal that the central Swiss Jura was at that time occupied by tidal flats and by more or less open marine lagoons where shoals and bioherms developed. The evolution through time of sedimentary facies and bed thicknesses permits the definition of small-, medium-, and large-scale depositional sequences. The diagnostic features of these sequences are independent of scale and seem largely controlled by the Kimmeridgian second-order transgression. A high-resolution sequence-stratigraphic correlation with biostratigraphically well-dated hemipelagic and pelagic sections in the Vocontian Basin in France reveals that: (i) The most important increase in accommodation recorded in the Kimmeridgian of the central Swiss Jura occurs in the Eudoxus ammonite zone (Late Kimmeridgian) and corresponds to the second-order maximum flooding recognized in many sedimentary basins. (ii) The small- and medium-scale sequences have time durations corresponding to the first and second orbital eccentricity cycle (i.e. 100 and 400 ka, respectively), suggesting that sedimentation on the platform and in the basin was at least partly controlled by cyclic environmental changes induced by insolation variations in the Milankovitch frequency band. The comparison of the high-resolution temporal framework defined in the Swiss Jura and Vocontian Basin with the sequence-stratigraphic interpretation realized in other Western European basins shows that the large-scale sequence boundaries defined in the Kimmeridgian of the Swiss Jura appear in comparable biostratigraphic positions in most Western European basins. Discrepancies that occur are probably because of local or regional tectonics.  相似文献