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In the words of the noted Antillean geologist C.T. Trechmann (1937 , p.337), 'Barbados, 21 miles long, 14 miles wide, rising to 1101 feet, is probably the most considerable Pleistocene non-volcanic bleb on the face of our planet, at least in the Antillean region.' The island's geology shows a stark contrast between the allochthonous siliciclastic succession of an accretionary prism, deposited in water depths measurable in kilometres, and the autochthonous Pleistocene raised reef cap exposed over 90 per cent of Barbados. 相似文献
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Harper, B.A. and Sobey, R.J., 1983. Open-boundary conditions for open-coast hurricane storm surge. Coastal Eng., 7: 41–60.The specification of realistic open-boundary conditions for the numerical simulation of hurricane (or tropical cyclone) storm surge is considered in the context of the very considerable spatial extent of the meteorological forcing. Existing practice is reviewed and an alternative approach, a Bathystrophic Storm Tide approximation to open-boundary water levels, is presented. Results from a series of numerical experiments demonstrate the advantages of this approach over existing methods. 相似文献
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Effects of observed and experimental climate change on terrestrial ecosystems in northern Canada: results from the Canadian IPY program 总被引:1,自引:0,他引:1
Gregory H. R. Henry Karen A. Harper Wenjun Chen Julie R. Deslippe Robert F. Grant Peter M. Lafleur Esther Lévesque Steven D. Siciliano Suzanne W. Simard 《Climatic change》2012,115(1):207-234
Tundra and taiga ecosystems comprise nearly 40?% of the terrestrial landscapes of Canada. These permafrost ecosystems have supported humans for more than 4500?years, and are currently home to ca. 115,000 people, the majority of whom are First Nations, Inuit and Métis. The responses of these ecosystems to the regional warming over the past 30?C50?years were the focus of four Canadian IPY projects. Northern residents and researchers reported changes in climate and weather patterns and noted shifts in vegetation and other environmental variables. In forest-tundra areas tree growth and reproductive effort correlated with temperature, but seedling establishment was often hindered by other factors resulting in site-specific responses. Increased shrub cover has occurred in sites across the Arctic at the plot and landscape scale, and this was supported by results from experimental warming. Experimental warming increased vegetation cover and nutrient availability in most tundra soils; however, resistance to warming was also found. Soil microbial diversity in tundra was no different than in other biomes, although there were shifts in mycorrhizal diversity in warming experiments. All sites measured were sinks for carbon during the growing season, with expected seasonal and latitudinal patterns. Modeled responses of a mesic tundra system to climate change showed that the sink status will likely continue for the next 50?C100?years, after which these tundra systems will likely become a net source of carbon dioxide to the atmosphere. These IPY studies were the first comprehensive assessment of the state and change in Canadian northern terrestrial ecosystems and showed that the inherent variability in these systems is reflected in their site-specific responses to changes in climate. They also showed the importance of using local traditional knowledge and science, and provided extensive data sets, sites and researchers needed to study and manage the inevitable changes in the Canadian North. 相似文献
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Stephen K. Donovan Trevor A. Jackson David A.T. Harper Roger W. Portell Willem Renema 《Geology Today》2014,30(4):151-158
Antigua is a small island at the northern end of the Lesser Antilles chain. Its geology is largely limited to the Upper Oligocene and it records with unusual fidelity the transition from island arc volcanism to quiescence and limestone deposition. Despite the apparent limitation of a rock record confined to a short stratigraphical interval, Antigua has a geodiversity that ranges from thick andesites through silicified logs and freshwater snails in cherts to limestones that include both shallow and deeper water facies, and fine karstic features. 相似文献
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David A.T. Harper 《地学学报》1992,4(2):204-209
Statistical analysis of mainly mid to deep-shelf Ordovician brachiopod faunas from localities within and marginal to the Appalachian- Caledonian Orogen reveals biogeographical patterns not entirely consistent with those presumed for the progressive orthogonal closure of the Iapetus Ocean. Correspondence analysis of faunas of late Arenig-early Llanvirn, late Llandeilo-earliest Caradoc and late Ashgill age emphasize the importance of marginal and island faunas, the role of regressions and transgressions on faunal distributions and the effects of climatic change in the definition of biogeographical trends during the Ordovician. 相似文献
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D. A. T. Harper 《Geological Journal》1982,17(4):251-277
The Drummuck Group of the Girvan district (S. W. Scotland) comprises a varied sequence of marine siliciclastic sedimentary rocks some 350 m thick and ranging in age from early Cautleyan to late Rawtheyan (Ashgill Series). Deposition in an unstable slope environment is envisaged. These upper Ordovician rocks crop out in the centre of the Craighead inlier, north of the Girvan valley and are sporadically exposed and locally very fossiliferous. A detailed revision of the Drummuck rocks has permitted, for the first time, the formal lithostratigraphical division of the group. Four main units, in ascending order, the Auldthorns, Quarrel Hill, Lady Burn and South Threave formations are recognized and, within these, a number of smaller, useful divisions are defined. Detailed geological maps of the Drummuck outcrop are presented. Brachiopods numerically dominate the shelly faunas and all the divisions named are characterized by distinctive brachiopod assemblages. Preliminary correlations are discussed with selected upper Ordovician successions elsewhere but the emphasis of this study is placed upon the establishment of a stratigraphical framework within which future detailed research on the Drummuck faunas may be carried out. 相似文献