Pervasive subsurface dolomitisation of the Devonian Nisku Formation,Canada — New insights from Reaction Transport Modeling     

Hans G. Machel  Fiona F. Whitaker  Gareth D. Jones 《Journal of Geochemical Exploration》2009

  相似文献   

Mobility and fisherfolk livelihoods on Lake Victoria: Implications for vulnerability and risk   总被引：1，自引：0，他引：1  

Fiona Nunan 《Geoforum》2010,41(5):776-785

Migration forms an essential livelihood strategy for many fisherfolk in the developing world, largely responding to fluctuating fish availability and prices. On Lake Victoria, East Africa, most migration is characterized by movement between landing sites, particularly of male boat crew responding to localised changes in fish productivity and using social networks to identify better fishing grounds and areas of higher fish prices. This article uses the sustainable livelihoods framework to identify the risks and vulnerabilities mitigated, or generated, by fisherfolk movement, and analyses how these sources of vulnerability affect livelihood outcomes, looking at the experiences and situation of both male boat crew and women involved in processing and trading fish. Whilst vulnerability due to lower catches and reduced income is mitigated through movement, these sources of vulnerability are exchanged for vulnerability arising from risky sexual behaviour and increased fishing pressure.  相似文献   

Lithospheric architecture and tectonic evolution of the Hudson Bay region     

David W. Eaton  Fiona Darbyshire 《Tectonophysics》2010,480(1-4):1-22

Hudson Bay conceals several fundamental tectonic elements of the North American continent, including most of the ca. 1.9–1.8 Ga Trans-Hudson orogen (THO) and the Paleozoic Hudson Bay basin. Formed due to a collision between two cratons, the THO is similar in scale and tectonic style to the modern Himalayan–Karakorum orogen. During collision, the lobate shape of the indentor (Superior craton) formed an orogenic template that, along with the smaller Sask craton, exerted a persistent influence on the tectonic evolution of the region resulting in anomalous preservation of juvenile Proterozoic crust. Extensive products of 2.72–2.68 Ga and 1.9–1.8 Ga episodes of subduction are preserved, but the spatial scale of corresponding domains increases by roughly an order-of-magnitude (to 1000 km, comparable to modern subduction environments) from the Archean to the Proterozoic. Based on analysis of gravity and magnetic data and published field evidence, we propose a new tectonic model in which Proterozoic crust in the southeastern third of Hudson Bay formed within an oceanic or marginal-basin setting proximal to the Superior craton, whereas the northwestern third is underlain by Archean crust. An intervening central belt truncates the southeastern domains and is interpreted to be a continental magmatic arc.Thick, cold and refractory lithosphere that underlies the Bay is well imaged by surface-wave studies and comprises a large component of the cratonic mantle keel beneath North America. The existence of an unusually thick mantle root indicates that subduction and plate collision during the Trans-Hudson orogeny were ‘root-preserving’ (if not ‘root-forming’) processes. Although the Hudson Bay basin is the largest by surface area of four major intracratonic basins in North America, it is also the shallowest. Available evidence suggests that basin subsidence may have been triggered by eclogitization of lower-crustal material. Compared to other basins of similar age in North America, the relatively stiff lithospheric root may have inhibited subsidence of the Hudson Bay basin.  相似文献   

Urban geology in wales: 3, edited by M.G. Bassett, H. Boulton & D. Nichol. National Museums of Wales,Cardiff, 2009. No. of pages: 198. ISBN 978‐0‐7200‐0594‐3 (paperback).     

Fiona E. Fearnhead 《Geological Journal》2014,49(2):220-220

  相似文献   

‘About Time the Regions Were Recognised’: interpreting region-building in Western Australia     

Valerià Paül  Fiona Haslam McKenzie 《The Australian geographer》2015,46(3):363-388

The region-building process in Western Australia is examined using Paasi's theoretical framework of ‘regional institutionalisation’. The paper examines the formalisation of the regions in Western Australia from the 1940s with the first attempts to regionalise the State, through to the recent political and policy shifts. A particular focus is given to the pivotal legislation passed in 1993 which created nine Regional Development Commissions, and the implications of the post-2008 Royalties for Regions program. The discussion examines the trajectory of the Western Australia regions through the lens of Paasi's model. The paper shows that the Regional Development Commissions have had a critical role in fulfilling the different stages of the model.  相似文献   

Flash flood at Slheimajkull heralds the reawakening of an Icelandic subglacial volcano     

Andrew J. Russell  Fiona S. Tweed  & Óskar Knudsen 《Geology Today》2000,16(3):102-106

An unpredicted sudden outburst flood from Sólheimajökull, Southern Iceland, in July 1999 may herald a major subglacial volcanic eruption beneath Mýrdalsjökull ice cap.  相似文献   

Low‐grade metamorphism of mafic lavas,Upper Permian Broughton Formation,Sydney Basin     

P. F. Carr  J. W. Pemberton  E. Nunan 《Australian Journal of Earth Sciences》2013,60(6):839-849

Coexisting primary minerals and hydrous alteration minerals in basalt lavas of the Upper Permian Broughton Formation of the Sydney Basin are indicative of the involvement of a hydrothermal fluid phase during low‐grade metamorphism. Variation and zonation of alteration phases in vesicles and vugs indicate that the alteration minerals developed in response to several episodes of precipitation, with early CO₂‐rich fluids producing assemblages rich in calcite and chlorite‐smectite while later CO₂‐poor fluids precipitated Ca‐zeolites, prehnite and pumpellyite. Vesicular parts of flows typically show much higher contents of alteration minerals than more massive parts of the same flow, but no systematic increase in either the style or intensity of alteration with increasing depth in the lava pile is evident. The presence of Ca‐zeolites, prehnite, pumpellyite and rare epidote suggests uppermost zeolite facies to lowermost prehnite‐pumpellyite facies metamorphism. Stability relationships of the metamorphic phases based on experimental and theoretical studies, used in conjunction with measured parameters for modern geothermal systems, indicate a peak metamorphic temperature of ～200–230°C while the extant stratigraphy indicates that the maximum depth of burial was ～ 1200 m. Alteration developed in response to circulation of hot, aqueous fluids generated by thermal convection cells associated with the Permian lavas and/or a large buried intrusion.  相似文献   

Consequences of a simulated rapid ocean acidification event for benthic ecosystem processes and functions     

Fiona Murray  Stephen Widdicombe  C. Louise McNeill  Martin Solan 《Marine pollution bulletin》2013

Whilst the biological consequences of long-term, gradual changes in acidity associated with the oceanic uptake of atmospheric carbon dioxide (CO₂) are increasingly studied, the potential effects of rapid acidification associated with a failure of sub-seabed carbon storage infrastructure have received less attention. This study investigates the effects of severe short-term (8 days) exposure to acidified seawater on infaunal mediation of ecosystem processes (bioirrigation and sediment particle redistribution) and functioning (nutrient concentrations). Following acidification, individuals of Amphiura filiformis exhibited emergent behaviour typical of a stress response, which resulted in altered bioturbation, but limited changes in nutrient cycling. Under acidified conditions, A. filiformis moved to shallower depths within the sediment and the variability in occupancy depth reduced considerably. This study indicated that rapid acidification events may not be lethal to benthic invertebrates, but may result in behavioural changes that could have longer-term implications for species survival, ecosystem structure and functioning.  相似文献   

Mimicking state diplomacy: The legitimizing strategies of unofficial diplomacies     

Fiona McConnell  Terri Moreau  Jason Dittmer 《Geoforum》2012,43(4):804-814

Diplomacy and recognition play central roles in the conventional conferral of state legitimacy and functioning of the inter-state system. In broadening the diplomatic frame by stepping outside the conventional state-system, this paper brings a poststructuralist and performative toolkit to mimetic diplomatic practices. Adapting Bhabha’s notion of mimicry to diplomatic discourse, it demonstrates how non-state diplomacies draw on, mimic and intervene in the realm of formal political action in ways which both promote ‘official’ state diplomacy as an ideal and dilute its distinction from other, ‘unofficial’ diplomacies. In thereby examining the enactment of international diplomacy in unexpected spaces, this paper brings together three empirical studies: a Government-in-Exile, a religious community and micropatrias (self-declared parodic nations). In each of these cases, attention focuses on: discourses of recognition; sovereignty and legitimacy; the diplomatic relationships fostered and institutions of diplomacy constructed; and the strategic position of such diplomacy vis-à-vis the conventional state-system. Unpacking the relationship between legitimacy, recognition and diplomacy and exploring the tension between state-centric and non-state diplomatic practices, this paper foregrounds the points of connection between the official and the unofficial. As a result, this paper expands the analytical gaze of diplomacy studies while incorporating lessons from the margins into our understandings of legitimacy, recognition, statecraft and sovereignty.  相似文献   

Habitat dynamics in the bed sediments of an intermittent upland stream     

Fiona J. McKenzie-Smith  Stuart E. Bunn  Alan P. N. House 《Aquatic Sciences - Research Across Boundaries》2006,68(1):86-99

  相似文献