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271.
This paper explores the concept of sustainable tourism and how it applies to urban destinations such as Singapore. As tourism is an important industry in Singapore, in terms of employment, business activity and an income generator, the Singapore Tourism Board is continuously looking at potential avenues to make Singapore a competitive destination. We examine the use of thematic zones in Singapore as a strategy to achieve its ambition of becoming a tourism capital of the world. By focusing on a case study of the Singapore River thematic zone (one of the 11 thematic zones identified by the Singapore Tourism Board), we assess the viability of thematic zones in ensuring sustainable urban tourism. The paper closes with some theoretical reflections and policy implications arising from our key findings. 相似文献
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Abstract Ophiolites of the Mirdita–Subpelagonian zone form a nearly continuous belt in the Albanide–Hellenide orogen, including mid‐ocean ridge basalt (MORB) associations in the western Mirdita sector and supra‐subduction zone (SSZ) complexes, with prevalent island arc tholeiitic (IAT) and minor boninitic affinities in the eastern part of the belt (i.e. eastern Mirdita, Pindos, Vourinos). In addition, basalts with geochemical features intermediate between MORB and IAT (MORB/IAT) are found in the central Mirdita and in the Aspropotamos sequence (Pindos). These basalts alternate with pure MORB and are cut by boninitic dykes. The distinctive compositional characteristics of the mafic magmas parental to the different ophiolitic suites can be accounted for by partial melting of mantle sources progressively depleted by melt extractions. Partial melting processes (10–20%) of lherzolitic sources generated pure MORB, leaving clinopyroxene‐poor lherzolite as a residuum. Approximately 10% water‐assisted partial melting of this latter source, in an SSZ setting, may in turn generate basalts with MORB/IAT intermediate characteristics, whereas IAT basalts and boninites may have been derived from 10–20% and 30% partial melting, respectively, of the same source variably enriched by subduction‐derived fluids. In addition, boninites may also have been derived by comparatively lower degrees of hydrated partial melting of more refractory harzburgitic sources. A generalized petrologic model based on mass balance calculations between bulk rock and mineral compositions, indicate that most of the intrusives (from ultramafic cumulates to gabbronorites and plagiogranites), as well as sheeted dykes and volcanics (from basalts to rhyodacites) forming the bulk crustal section of the SSZ ophiolites, may be accounted for by shallow fractional crystallization from low‐Ti picritic parental magmas very similar in composition to IAT picrites from Pacific intraoceanic arcs. The most appropriate tectono‐magmatic model for the generation of the SSZ Tethyan ophiolites implies low velocity plate‐convergence of the intraoceanic subduction and generation of a nascent arc with IAT affinity and progressive slab roll‐back, mantle diapirism and extension from the arc axis to the forearc region, with generation of MORB/IAT intermediate basalts and boninitic magmas. 相似文献
277.
Crust and upper mantle structure of the Ailao Shan-Red River fault zone and adjacent regions 总被引:4,自引:1,他引:4
XU Yi LIU Jianhua LIU Futian SONG Haibin HAO Tianyao & JIANG Weiwei Institute of Geology Geophysics Chinese Academy of Sciences Beijing China 《中国科学D辑(英文版)》2005,48(2):156-164
Using arrival data of the body waves recorded by seismic stations, we reconstructed the velocity structure of the crust and upper mantle beneath the southeastern edge of the Tibetan Plateau and the northwestern continental margin of the South China Sea through a travel time tomography technique. The result revealed the apparent tectonic variation along the Ailao Shan-Red River fault zone and its adjacent regions. High velocities are observed in the upper and middle crust beneath the Ailao Shan-Red River fault zone and they reflect the character of the fast uplifting and cooling of the metamorphic belt after the ductile shearing of the fault zone, while low velocities in the lower crust and near the Moho imply a relatively active crust-mantle boundary beneath the fault zone. On the west of the fault zone, the large-scale low velocities in the uppermost mantle beneath western Yunnan prove the influence of the mantle heat flow on volcano, hot spring and magma activities, however, the upper mantle on the eas 相似文献
278.
Wang Ruobai 《中国地震研究》2005,19(3):327-337
INTRODUCTIONThe Zhangjiakou-Penglai fault zone has drawnextensive attentionfromseismologists and geologistssince it was determinedinthe1980’s(Zheng Binghua,et al.,1981).Ma Xingyuan,et al.(1989)consideredit asthe north boundaryof North China sub-block.Int… 相似文献
279.
库水位变化对库岸边坡稳定性的影响 总被引:3,自引:0,他引:3
在假定坡体孔隙水水位为水平线且不考虑渗透作用影响的基础上,基于极限平衡法考察了水位上升及下降的快慢对边坡安全系数的影响。对比计算表明:在水位缓慢变化即坡体内外水位线等高的条件下,边坡的安全系数随着水位坡高比的增大先略减小后急剧增大,且在水位坡高比为0.3处取得最小值,在边坡完全淹没于水中时取得最大值。当边坡完全淹没于水中后,水位高于坡顶的多少对边坡安全系数没有影响;在水位骤降或陡升条件下,相同库水位对应的边坡安全系数基本上均小于水位缓慢变化情况下的安全系数,故工程实际中无论是排水还是蓄水,都应尽量保持水位缓慢变化,这样才能使边坡处于较安全的状态。 相似文献
280.
Numerical Modeling of Basin-Range Tectonics Related to Continent-Continent Collision 总被引:1,自引:0,他引:1
CUI Junwen SHI Jinsong LI Pengwu ZHANG Xiaowei GUO Xianpu DING Xiaozhong Institute of Geology Chinese Academy of Geological Sciences Beijing Hehai University Nanjing Jiangsu 《《地质学报》英文版》2005,79(1):24-35
Continent-continent collision is the most important driving mechanism for the occurrence of various geological processes in the continental lithosphere. How to recognize and determine continent-continent collision,especially its four-dimensional temporal-spatial evolution, is a subject that geological communities have long been concerned about and studied. Continent-continent collision is mainly manifested by strong underthrnsting (subduction) of the underlying block along an intracontinental subduction zone and continuous obduction (thrusting propagation) of the overlying block along the intracontinental subduction zone, the occurrence of a basin-range tectonic framework in a direction perpendicular to the subduction zone and the flexure and disruption of the Moho. On the basis of numerical modeling, the authors discuss in detail the couplings between various amounts and rates of displacement caused by basin subsidence, mountain uplift and Moho updoming and downflexure during obduction (thrusting propagation) and subduction and the migration pattern of basin centers. They are probably indications or criteria for judgment or determination of continent-continent collision. 相似文献