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271.
This paper examines the nature of environmental action in and around the home. Given the rise of local sustainable development and the emphasis placed on individual actions for sustainability, the paper examines the role of citizens in adopting sustainable lifestyles, incorporating a range of behavioural responses from energy saving and water conservation, to waste recycling and green consumption. Focussing on the debate in geography concerning the engagement of the public in environmental action, the paper argues that despite the assertions of those who advocate a deliberative approach to engagement (see [Owens, S., 2000. Engaging the public: information and deliberation in environmental policy. Environment and Planning A 32, 1141–1148]), an approach based on a social–psychological understanding of behaviour can have significant benefits. Such an approach is being developed by geographers in a range of settings and in this paper these developments are situated within the context of existing research that has identified environmental ‘activists’ in terms of their values, attitudes and demographic composition. The paper aims to examine environmental behaviour in relation to two key issues: (1) the way in which environmental action is framed in everyday practices (such as consumption behaviour) and (2) how these practices are reflected amongst different segments of the population to form lifestyle groups. The paper provides new insights for examining sustainable lifestyles that further our appreciation of how actions to help the environment are lived in everyday practices and framed by different lifestyle groups. Accordingly, the paper offers both academics and policy makers new insights into the potential use of focussing on lifestyle groups as a means for changing behaviour. 相似文献
272.
Jiří Žák František V. Holub Václav Kachlík 《International Journal of Earth Sciences》2006,95(5):771-789
The presence of numerous roof pendants, stoped blocks and discordant intrusive contacts suggests that magmatic stoping was a widespread, large-scale process during the final construction of the Central Bohemian Plutonic Complex, Bohemian Massif. The measured total length of the discordant contacts that cut off the regional cleavage and were presumably formed by stoping corresponds to about half of all contacts with the upper-crustal host rocks. In addition, at least some of the straight, cleavage-parallel intrusive contacts may also have recorded complex intrusive histories ending with piecemeal stoping of thin cleavage-bounded host rock blocks into the magma chamber. Based on the above, we argue that the fast strain rates required for emplacement of large plutons of the Central Bohemian Plutonic Complex into brittle upper crustal host rocks over relatively short-time span could not have been accommodated entirely by slow ductile flow or slip along faults. Instead, the emplacement was largely accommodated by much faster thermal cracking and extensive stoping independent of regional tectonic deformation. Finally, we emphasize that magmatic stoping may significantly modify the preserved structural patterns around plutons, may operate as an important mechanism of final construction of upper-crustal plutons and thus may contribute to vertical recycling and downward transport of crustal material within the magma plumbing systems in the crust. 相似文献
273.
冲绳海槽北、中段火山岩地球化学特征及其地质意义 总被引:10,自引:0,他引:10
为去除非火山物质对样品化学性质的影响,得到火山岩真实的地球化学及同位素组成数据,作者对采自冲绳海槽的酸性火山岩样品严格的前处理,其中海槽北段火山岩同位素数据以前还未见公开报道。根据所得U系同位素组成数据及其分布规律分辩混染物中俯冲板片的成分,结合Sr-Nd同位素组成,本文对海槽火山活动的岩石种类、物质来源和岩浆演化过程作了一些初步的讨论。结果表明,冲绳海槽酸性火山岩分布广泛,为钙碱性系列岩石,碱性弱(里特曼指数〈1.8);海槽岩浆主要源于地幔,源区同位素组成类似PREMA地幔,结晶分异作用是演化过程中最主要的地质作用,但岩浆也受到了不同程度地受到上地壳与/或俯冲板片物质的混入;根据混合模拟结果将海槽火山岩大致分成以上地壳物质混染为主和上地壳-俯冲板片混染两类,且认为上地壳混染发生在岩浆演化的晚期,此时岩浆体系SiO2含量要高于混染物。 相似文献
274.
意大利埃特纳火山的三维速度结构与地震活动性 总被引:2,自引:2,他引:0
本文的研究工作,得到了埃特纳火山下面的一组新的三维速度模型。作者们用1980年以来地方性地震在永久和临时地震台网在4个或更多台记录到的1249次地震的P和S波,被选来作走时反演。选择了几种判别标志与参数化办法以显示其类似的基本特征。表明在火山的东南象限在浅层,有P波的高速分怖,它同布格重力高异常有密切关系。在该区存在低的Vp/Vs比值;沿着中央火山管道,分布有高速P波和高的Vp/Vs比值;建议该处存在有稠密的侵入的岩浆体,延伸到20千米左右的深度,该区附近有低速的P波速度。对震源的重新定位也显示出向外倾斜的易碎区,与中央火山管道延伸出一段P波高速异常区,位于中央火山口的附近。沿着中央火山口附近,有P波的低速区,它同次生的火山锥的分布有关,与部份熔融的深部岩浆库有联系。 相似文献
275.
In a 60 Ma interval between the Late Carboniferous and the Late Permian, the magmatic arc associated with the cordilleran-type New England Fold Belt in northeast New South Wales shifted eastward and changed in trend from north–northwest to north. The eastern margin of the earlier (Devonian–Late Carboniferous) arc is marked by a sequence of calcalkaline lava flows, tuffs and coarse volcaniclastic sedimentary rocks preserved in the west of the Fold Belt. The younger arc (Late Permian–Triassic) is marked by I-type calcalkaline granitoids and comagmatic volcanic rocks emplaced mostly in the earlier forearc, but extending into the southern Sydney Basin, in the former backarc region. The growth of the younger arc was accompanied by widespread compressional deformation that stabilised the New England Fold Belt. During the transitional interval, two suites of S-type granitoids were emplaced, the Hillgrove Suite at about 305 Ma during an episode of compressive deformation and regional metamorphism, and the Bundarra Suite at about 280 Ma, during the later stages of an extensional episode. Isotopic and REE data indicate that both suites resulted from the partial melting of young silicic sedimentary rocks, probably part of the Carboniferous accretionary subduction complex, with heat supplied by the rise of asthenospheric material. Both mafic and silicic volcanic activity were widespread within and behind the Fold Belt from the onset of rifting (ca. 295 Ma) until the reestablishment of the arc. These volcanic rocks range in composition from MORB-like to calcalkaline and alkaline. The termination of the earlier arc, and the subsequent widespread and diverse igneous activity are considered to have resulted from the shallow breakoff of the downgoing plate, which allowed the rise of asthenosphere through a widening lithospheric gap. In this setting, division of the igneous rocks into pre-, syn-, and post-collisional groups is of limited value. 相似文献
276.
根据湖南的水文特性,从经济和社会发展的角度,分析湖南水文的作用以及与之不相适应的问题。结合本省实际提出发展湖南水文事业的基本思路。 相似文献
277.
岩浆岩型伴生金矿床的时空分布特征及区域控矿作用 总被引:1,自引:0,他引:1
从伴生金的角度对岩浆岩型矿床的时空分布特征及区域控矿作用进行了总结:划分了吉中、北阴山、富蕴、金川、玛沁、略阳、康滇、哀牢山八个成矿带;指出岩浆岩型伴生金矿床最主要的成矿期为元古代和晚古生代;强调台褶过渡区及褶皱过渡区、深大断裂、基性超基性岩的区域控矿作用。 相似文献
278.
轻质填充墙异型柱框架弹性阶段地震作用计算 总被引:1,自引:0,他引:1
本文在四个模型试验研究基础上,建立了轻质填充墙与异型柱框架共同工作的弹性动力计算模型,给出了结构弹性阶段地震作用的计算方法。 相似文献
279.
Melt and fluid inclusions in minerals from the peralkaline granite intrusion and associated mineralized country rocks from the Yermakovka F–Be deposit were studied to characterize the behaviour of trace elements and exsolved fluids in the transition from magmatic to hydrothermal processes. Ore mineralization was mostly due to volatile release from a deep-seated pluton for which crystallization history and fluid exsolution can be tracked by three batches of magma (Gr1→Gr3) intruded at the level of the ore deposition to form the Yermakovka stock. Each batch of the sequential granite group is found to intrude at decreasing temperature (from 840 to 730 °C) and progressively increasing extent of crystallization of magma in the parental pluton. This resulted in the enrichment of the ascending melts in H2O (3.9 to 6.1 wt.%), F (2.6 to 4.1 wt.%) and some incompatible elements (Zr, Nb, Th, Rb, Pb). Although the earliest evidence for the exsolution of homogeneous fluoride–sulphate brine correlates with the final stage of the Gr2 ascent, the most intensive volatile(s) release from the emplaced magmas is shown to occur during their in situ crystallization, which was associated with the separation of exsolved fluid into immiscible phases, brine and low-salinity solution. Compositions of these fluid phases are determined using atomic emission spectroscopy of the appropriate fluid inclusions opened by a laser microprobe and EMPA and SEM–EDS analyses of daughter crystals. The brine phase is enriched in Mo, Mn, Be (up to 17, 8, and 0.3 g/kg, respectively) and contains perceptible abundances of Ce, La, Pb, Zn, whereas the low-salinity phase is enriched only in Be (up to 0.6 g/kg). The selective mobilization of the metals from the melt into fluids is considered to result from the oxidized state of the melt and fluids, peralkalinity of the melt during crystallization, and high F content of the melt. The immiscible fluid phases are shown to migrate together through the solidifying stock giving rise to the albitized granite that is enriched in molybdenite but devoid of Be minerals. In the country rocks, solutions similar to the brine and low-salinity phases of the magmatic fluid made up separate fluid flows, which produced Be and Mo mineralization and were issued predominantly from the parental pluton. Both types of mineralization are nearly monometallic which suggests that of the metals, jointly transported by the brine, only Mo and, in part, Ce and La precipitated separately at the level where the low-salinity solutions deposited Be ores. 相似文献
280.
Ilya V. Veksler 《Chemical Geology》2004,210(1-4):7-31
Several types of fluid immiscibility may affect the evolution of volatile-rich magmatic systems at the magmatic–hydrothermal transition. The topology of silicate–salt–H2O systems implies that three-fluid immiscibility (silicate melt+hydrosaline melt+vapour) should be stable in a broad range of compositions and P–T conditions. The most important factor controlling the immiscibility appears to be the Coulombic properties (electric charges Z and ionic radii r) of the main network-modifying cations and the capacity for immiscibility appears to decrease in the following sequence: Mg>Ca>Sr>Ba>Li>Na>K. Liquid immiscibility is enhanced in peralkaline compositions and in the presence of nonsilicate anions such as F−, Cl−, CO32− and BO33−. In volatile-rich magmatic systems, the H2O is likely to react with the chloride, fluoride, borate and carbonate species and the chemical effects of high-temperature hydrolysis may be greatly enhanced by phase separation in systems with multiple immiscible fluid phases. Natural granitic magmas can thus exsolve a range of chemically and physically diverse hydrosaline liquids and the role of these fluid phases is likely to be especially significant in pegmatites and Li–F rare-metal granites. 相似文献