TIMS and SHRIMP U–Pb analyses of zircons from Milford Orthogneiss metadiorite (P = 1–1.4 GPa; T ≥ 750°C) of the Arthur River Complex of northern Fiordland reveal a bimodal age pattern. Zircons are predominantly either
Paleozoic (357.0 ± 4.2 Ma) and prismatic with oscillatory zoning, or Cretaceous (133.9 ± 1.8 Ma) and ovoid with sector or
patchy zoning. The younger age component is not observed overgrowing older grains. Most grains of both ages are overgrown
by younger Cretaceous (~120 Ma) metamorphic zircon with very low U and Th/U (0.01). We interpret the bimodal ages as indicating
initial igneous emplacement and crystallisation of a dioritic protolith pluton at ~357 Ma, followed by Early Cretaceous granulite-facies
metamorphism at ~134 Ma, during which a significant fraction (~60%) of the zircon grains dissolved, and subsequently reprecipitated,
effectively in situ, in partial melt pockets. The remaining ~40% of original Paleozoic grains were apparently not in contact
with the partial melt, remained intact, and show only slight degrees of Pb loss. Sector zoning of the Cretaceous grains discounts
their origin by solid state recrystallisation of Paleozoic grains. The alternative explanation—that the Paleozoic component
represents a 40% inherited component in an Early Cretaceous transgressive dioritic magma—is considered less likely given the
relatively high solubility of zircon in magma of this composition, the absence of 134 Ma overgrowths, the single discrete
age of the older component, equivalent time-integrated 177Hf/176Hf compositions of both age groups, and the absence of the Cambrian-Proterozoic detrital zircon that dominates regional Cambro-Ordovician
metasedimentary populations. Similar bimodal Carboniferous-Early Cretaceous age distributions are characteristic of the wider
Arthur River Complex; 8 of 12 previously dated dioritic samples have a Paleozoic component averaging 51%. Furthermore, the
age and chemical suite affinity of these and several more felsic rocks can be matched with those of the relatively unmetamorphosed
Carboniferous plutonic terrane along the strike of the Mesozoic margin in southern Fiordland, also supporting the in situ
derivation of the Carboniferous “inherited” component. 相似文献
We present an Atlas of ShakeMaps and a catalog of human population exposures to moderate-to-strong ground shaking (EXPO-CAT)
for recent historical earthquakes (1973–2007). The common purpose of the Atlas and exposure catalog is to calibrate earthquake
loss models to be used in the US Geological Survey’s Prompt Assessment of Global Earthquakes for Response (PAGER). The full
ShakeMap Atlas currently comprises over 5,600 earthquakes from January 1973 through December 2007, with almost 500 of these
maps constrained—to varying degrees—by instrumental ground motions, macroseismic intensity data, community internet intensity
observations, and published earthquake rupture models. The catalog of human exposures is derived using current PAGER methodologies.
Exposure to discrete levels of shaking intensity is obtained by correlating Atlas ShakeMaps with a global population database.
Combining this population exposure dataset with historical earthquake loss data, such as PAGER-CAT, provides a useful resource
for calibrating loss methodologies against a systematically-derived set of ShakeMap hazard outputs. We illustrate two example
uses for EXPO-CAT; (1) simple objective ranking of country vulnerability to earthquakes, and; (2) the influence of time-of-day
on earthquake mortality. In general, we observe that countries in similar geographic regions with similar construction practices
tend to cluster spatially in terms of relative vulnerability. We also find little quantitative evidence to suggest that time-of-day
is a significant factor in earthquake mortality. Moreover, earthquake mortality appears to be more systematically linked to
the population exposed to severe ground shaking (Modified Mercalli Intensity VIII+). Finally, equipped with the full Atlas
of ShakeMaps, we merge each of these maps and find the maximum estimated peak ground acceleration at any grid point in the
world for the past 35 years. We subsequently compare this “composite ShakeMap” with existing global hazard models, calculating
the spatial area of the existing hazard maps exceeded by the combined ShakeMap ground motions. In general, these analyses
suggest that existing global, and regional, hazard maps tend to overestimate hazard. Both the Atlas of ShakeMaps and EXPO-CAT
have many potential uses for examining earthquake risk and epidemiology. All of the datasets discussed herein are available
for download on the PAGER Web page ().
T. I. Allen and M. G. Hearne—contracted through Synergetics Incorporated. 相似文献
The purposes of the paper are to provide a historical and thematic review of some of the variants of American philosophical pragmatism (old and new), and to point to its potential relevance for geography. The paper is divided into three sections. The first, discusses the origins of American pragmatism focussing on four figures: John Dewey, Oliver Wendell Holmes, William James, and Charles Sanders Peirce. Following the argument of Louis Menand (2001) in The Metaphysical Club, I will suggest that pragmatism took on its peculiar American character as a response to the deep fissures and wounds caused by that country’s Civil War. That war produced a loss of faith, undermining notions of universal progress and absolute truth. Pragmatism was the reaction. The second section brings pragmatism to the present, by focussing on three connected contemporary American pragmatists: Richard Rorty, Richard Bernstein, and Richard Shusterman. The hallmark of their work, and which justifies treating them as a group, is a willingness to stretch pragmatism: first, by making linkages with other anti-foundational, practice-based philosophical traditions, especially those within Continental European philosophy, and which had been shut out of Anglo-American philosophy after the Second World War by the rise of analytic philosophy; and second, by applying pragmatist ideas to issues like the body and popular culture to which it had never been applied. Finally, in the conclusion the paper reflects on the prospects of tethering pragmatism to the work of human geographers. Given the anti-architectonic impulses of pragmatism, such a project cannot simply be one of holus-bolus transferring pragmatism to geography. A different approach is needed, and which is schematically outlined and briefly illustrated using the idea of place. 相似文献
Agriculture is responsible for approximately 25% of anthropogenic global GHG emissions. This significant share highlights the fundamental importance of the agricultural sector in the global GHG emissions reduction challenge. This article develops and tests a methodology for the integration of agricultural and energy systems modelling. The goal of the research is to extend an energy systems modelling approach to agriculture in order to provide richer insights into the dynamics and interactions between the two (e.g. in competition for land-use). We build Agri-TIMES, an agricultural systems module using the TIMES energy systems modelling framework, to model the effect of livestock emissions and explore emissions reduction options. The research focuses on Ireland, which is an interesting test case for two reasons: first, agriculture currently accounts for about 30% of Ireland's GHG emissions, significantly higher than other industrialized countries yet comparable with global levels (here including emissions associated with other land-use change and forestation); second, Ireland is both a complete and reasonably sized agricultural system to act as a test case for this new approach. This article describes the methodology used, the data requirements, and technical assumptions made to facilitate the modelling. It also presents results to illustrate the approach and provide associated initial insights.
Policy relevance
Most of the policy focus with regard to climate mitigation targets has been on reducing energy-related CO2 emissions, which is understandable as they represent by far the largest source of emissions. Non-energy-related GHG emissions – largely from agriculture, industrial processes, and waste – have received significantly less attention in policy discourse. Going forward, however, if significant cuts are made in energy-related CO2 emissions, the role of non-energy-related GHG emissions will grow in importance. It is therefore crucial that climate mitigation analyses and strategies are not limited to the energy system. This article shows the value of using integrated energy and agriculture techno-economic modelling techniques to draw evidence for new comprehensive climate policy strategies able to discern between the full range of technical solutions available. It enables the production of economy-wide least-cost climate mitigation pathways. 相似文献
Resilience is an increasingly important concept within urban studies, economic geography, and evolutionary economics for measuring the capacity of city-regions to respond to economic shocks. In this article, we provide a sympathetic critique of the resilience metaphor in urban studies, which we explicate through an analysis of the recent history of the Vancouver economy. On the surface, Vancouver seemingly showed resilience when it overcame the abrupt decline of its resource-based economy in the 1980s, and established an alternative flourishing “new economy” by the 1990s. But over the last five years, the key local “creative” industries such as video game development and film production have suffered, with a number of large firms leaving Vancouver, and industry employment declining sharply. Drawing on more than 40 interviews conducted over a five-year period with members of the local video game community, our paper documents the rise and more recent decline of Vancouver’s “new economy” sector. Our research raises questions about the value of the resilience metaphor in urban studies and highlights the difficulties facing city-regions reliant on highly mobile “new economy” industries. 相似文献
The term cabbeling describes the convection that can occur when a mixture of two oceanic water masses is more dense than both of the parent water masses. When the two water masses are situated one above the other, the temperature and salinity distributions are in the correct senses for double-diffusive convection to occur and it is found that the prime effects of the nonlinearity of the equation of state are firstly to drive a greater level of double-diffusive convective activity in the lower layer than in the upper layer, and secondly, to make the lower edge of the interfacial region less gravitationally stable. Both of these effects cause the interface to migrate upwards as the lower layer grows at the expense of the upper layer. We introduce a nondimensional parameter (called the cabbeling parameter) which represents the importance of the nonlinearity of the equation of state:— is zero when the equation of state is linear and when cabbeling is normally thought to be possible, is greater than unity. Experiments set up in both the finger and diffuse sense show how the nondimensional measure of the upward interface migration (called the “entrainment” parameter ) varies with the density anomaly ration R? for various values of between zero and 2.0 and that no abrupt change in this behaviour occurs at . It is impossible to explain these observation by neglecting double-diffusive convection and considering only the convection driven by the conventional cabbeling instability. The successful interpretation of the laboratory results relies on considering the effects of a non-linear equation of state on the double-diffusive convection process. 相似文献
The island of Tobago is only about 40 km in length and to the geologist is a demonstration of the old saying that good things come in small packages. Situated in the southeast corner of the Caribbean Plate, it is the eastern extremity of the Caribbean Mountain System of northern South America, and is divided into three geologic provinces, one metamorphic, one igneous and one sedimentary. 相似文献
In a recently published paper, Worm et al. [Impacts of biodiversity loss on ocean ecosystem services. Science 2006;314:787–90.] project “the global collapse of all taxa currently fished” by 2048. Using their criteria and data, this paper shows that the number of not-collapsed fisheries actually increased over time to a plateau of about 5600 in 1985–2003. Furthermore, if trends are projected into the future, more than half of the world's fisheries would always be in a recovered state. 相似文献