Market access,population density,and socioeconomic development explain diversity and functional group biomass of coral reef fish assemblages     

Tom D. Brewer  Joshua E. Cinner  Rebecca Fisher  Alison Green  Shaun K. Wilson 《Global Environmental Change》2012,22(2):399-406

There is overwhelming evidence that many local-scale human activities (e.g. fishing) have a deleterious effect on coral reef fish assemblages. Our understanding of how broad social phenomena (e.g. socioeconomic development) affect the diversity and function of coral reef fish assemblages however, is still poor. Here, we use structural equation models to reveal how human population density, socioeconomic development, and market access affect fishing pressure and coral cover to, in turn, explain the diversity and biomass of key functional groups of reef fish assemblages within Solomon Islands. Fishing pressure is predominantly driven by both market access and local population density, and has a clear negative effect on the diversity and function of coral reef fishes. The strong positive effect of market access on fishing pressure makes clear the importance of understanding social-ecological linkages in the context of increasingly connected societies. This study highlights the need to address broad social phenomena rather than focusing on proximate threats such as fishing pressure, to ensure the continued flow of coral reef goods and services in this time of rapid global social and environmental change.  相似文献   

Structural and metamorphic evolution of the Moornambool Metamorphic Complex,western Lachlan Fold Belt,southeastern Australia     

G. Phillips  J. McL. Miller  C. J. L. Wilson 《Australian Journal of Earth Sciences》2013,60(5):891-913

The wedge‐shaped Moornambool Metamorphic Complex is bounded by the Coongee Fault to the east and the Moyston Fault to the west. This complex was juxtaposed between stable Delamerian crust to the west and the eastward migrating deformation that occurred in the western Lachlan Fold Belt during the Ordovician and Silurian. The complex comprises Cambrian turbidites and mafic volcanics and is subdivided into a lower greenschist eastern zone and a higher grade amphibolite facies western zone, with sub‐greenschist rocks occurring on either side of the complex. The boundary between the two zones is defined by steeply dipping L‐S tectonites of the Mt Ararat ductile high‐strain zone. Deformation reflects marked structural thickening that produced garnet‐bearing amphibolites followed by exhumation via ductile shearing and brittle faulting. Pressure‐temperature estimates on garnet‐bearing amphibolites in the western zone suggest metamorphic pressures of ～0.7–0.8 GPa and temperatures of ～540–590°C. Metamorphic grade variations suggest that between 15 and 20 km of vertical offset occurs across the east‐dipping Moyston Fault. Bounding fault structures show evidence for early ductile deformation followed by later brittle deformation/reactivation. Ductile deformation within the complex is initially marked by early bedding‐parallel cleavages. Later deformation produced tight to isoclinal D₂ folds and steeply dipping ductile high‐strain zones. The S₂ foliation is the dominant fabric in the complex and is shallowly west‐dipping to flat‐lying in the western zone and steeply west‐dipping in the eastern zone. Peak metamorphism is pre‐ to syn‐D₂. Later ductile deformation reoriented the S₂ foliation, produced S₃ crenulation cleavages across both zones and localised S₄ fabrics. The transition to brittle deformation is defined by the development of east‐ and west‐dipping reverse faults that produce a neutral vergence and not the predominant east‐vergent transport observed throughout the rest of the western Lachlan Fold Belt. Later north‐dipping thrusts overprint these fault structures. The majority of fault transport along ductile and brittle structures occurred prior to the intrusion of the Early Devonian Ararat Granodiorite. Late west‐ and east‐dipping faults represent the final stages of major brittle deformation: these are post plutonism.  相似文献   

A conduit-related genesis of the Lengshuiqing intrusive assemblage (Sichuan,SW China)     

Marian Munteanu  Allan H. Wilson  Yong Yao  Shao-Yong Jiang  Gordon Chunnett  Yaonan Luo  Leonard Mafurutu  Rofhiwa Phadagi 《Journal of Volcanology and Geothermal Research》2010,189(1-2):118-130

Lengshuiqing is part of the late Proterozoic igneous province from the western margin of the Yangtze craton. The Lengshuiqing area comprises five ultramafic–mafic intrusions, emplaced in the late Proterozoic Yanbian Group. The intrusions from Lengshuiqing contain cumulate ultramafic zones (peridotite + olivine pyroxenite), with cumulus olivine and Cr-spinel, and intercumulus pyroxenes, hornblende, phlogopite and plagioclase. Ni–Cu ore (pyrrhotite + pentlandite + chalcopyrite) is hosted in the ultramafic zones. Olivine-free diorite–quartz diorite ± gabbro and granite zones commonly occur above the ultramafic rocks. The genesis of the intrusions (conduit-related accumulation or differentiation from stagnant magma) was investigated. The amount of sulphides in the intrusions from Lengshuiqing is one order of magnitude bigger than the sulphides that can be dissolved by a volume of mafic magma similar with the volume of the intrusions. Most intrusions from Lengshuiqing have bulk composition (peridotite ± diorite ± granite) more magnesian (MgO = 21–22%; Mg# > 78) than the deduced composition of their parental magma (MgO = 9–11%; Mg# = 64–67). This indicates the accumulation of sulphide and mafic silicates from a volume of magma much bigger than the volume of the intrusions, which can be explained by the fractionation from magma ascending through the intrusions to shallower depths. A continuous supply and vent of magma is consistent with the lack of chilled margins, the melting of the wall rocks and the generation of high-temperature mineral assemblages (K-feldspar, diopside, and sillimanite) in the Yanbian Group. The intrusions from Lengshuiqing are seen as microchambers on conduits draining olivine-, Cr-spinel-, and sulphide-bearing mafic magma from a larger staging chamber.  相似文献   

Erratum to “Quantifying carbon fixation in trace minerals from processed kimberlite: A comparative study of quantitative methods using X-ray powder diffraction data with applications to the Diavik Diamond Mine,Northwest Territories,Canada” [Appl. Geochem. 24 (12) (2009) 2312–2331]     

Siobhan A. Wilson  Mati RaudseppGregory M. Dipple 《Applied Geochemistry》2010

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Seismic and sedimentologic features of Oxfordian-Kimmeridgian syn-rift sediments on the eastern margin of the Lusitanian Basin     

R. R. Leinfelder  R. C. L. Wilson 《International Journal of Earth Sciences》1989,78(1):81-104

Following deposition of widespread middle Oxfordian lacustrine carbonates and evaporites, the Lusitanian Basin was differentiated into a number of sub-basins. The Arruda sub-basin is a half graben basin situated some 30 km north of Lisbon. It accumulated over 2.5 km of Kimmeridgian siliciclastic sediments, and is bounded to the east by the Vila Franca de Xira fault zone. Carbonate deposition persisted over horsts along the fault zone from the Oxfordian to the early Kimmeridgian, and in places to the late Kimmeridgian, and shows a pronounced west-east facies zonation, with higher energy framestones and grainstones accumulating along the exposed western margins. Seismic data indicate a major gap between the horst blocks that acted as a conduit through which basement derived siliciclastics were fed westwards into the sub-basin to form a submarine fan system. The presence of large blocks of framestone carbonates encased in siliciclastics indicates that carbonate sedimentation occurred in abandoned parts of the fan system. The rapid changes of sediment thicknesses and facies types along the eastern margin of the Arruda sub-basin are indicative of contemporaneous strike-slip movements.

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Zusammenfassung Nach der weitverbreiteten Ablagerung mitteloxfordischer Seenkarbonate und Evaporite differenzierte sich das Lusitanische Becken in verschiedene Sub-Becken. Das Arruda Sub-Becken befindet sich ca. 30 km nördlich Lissabon und entspricht einem Halbgraben, in dem über 2.5 km mächtige Siliziklastika des Kimmeridgium zur Ablagerung kamen. Das Sub-Becken wird durch die Störungszone von Vila Franca de Xira nach Osten begrenzt. Auf Horststrukturen entlang der Störungszone wurden im Oxfordium und Unterkimmeridgium, z. T. auch bis ins Oberkimmeridgium Karbonate sedimentiert. Diese Karbonatschelfe weisen eine ausgeprägte Fazieszonierung von West nach Ost auf. Die westlichen Schelfränder sind durch höherenergetische Riffkalke (framestones) und Karbonatsande (grainstones) charakterisiert. Seismische Profile lassen eine große Lücke zwischen den Horstblöcken erkennen, durch welche Siliziklastika aus dem Hinterland ins Sub-Becken gelangten, wo sie einen submarinen Fächer aufbauten. Große Riffkalkblöcke innerhalb der Siliziklastika weisen auf Karbonatsedimentation in verlassenen Fächerbereichen hin. Die schnellen Mächtigkeits- und Fazieswechsel entlang des Ostrandes des Arruda Sub-Beckens sind durch synsedimentäre tektonische Bewegungen zu erklären, welche oftmals eine Dominanz der Lateralkomponente aufweisen.

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Resumo Depois da sedimentação dos calcários lacustres e depósitos evaporíticos da idade Oxfordiano médio, a Bacia Lusitánica diferenciou-se em várias sub-bacias. A sub-bacia de Arruda está situada ca. de 30 km ao norte de Lisboa e corresponde a uma estrutura «half-graben» em que mais do que 2.5 km de sedimentos foram acumulados. Para leste, a sub-bacia é limitada pela zona das falhas de Vila Franca de Xira. Entre o Oxfordiano e o Kimeridgiano, calcários desenvolveram-se em cima dos blocos elevados (horsts) ao longo da zona de falhas. Estes calcários de tipo plataforma exibem uma distincta zonação de facies de oeste a leste. As margens occidentals das plataformas pequenas são caracterisadas por sedimentos recifais e areníticos. Cortes sísmicos indicam uma abertura grande entre os blocos elevados, pelo quai sedimentos siliciclásticos passaram de hinterland à sub-bacia formando um fan submarino. Grandes blocos recifais situados dentro dos depósitos siliciclásticos são evidências para sedimentação carbonática em várias áreas abandonadas dentro do fan. Mudanças rápidas das espessuras e das fácies dos sedimentos ao longo da margem oriental da sub-bacia de Arruda podiam ser explicadas por uma tectónica sinsedimentária dominada por movimentos horizontais.

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A second-order closure model for flow through vegetation   总被引：2，自引：0，他引：2  

J. D. Wilson 《Boundary-Layer Meteorology》1988,42(4):371-392

By splitting the turbulent kinetic energy into two wavebands and adopting as the turbulence timescale the ratio k/ of the kinetic energy in the low-frequency band to its turnover-rate, the second-order closure scheme of Launder et al. (1975) has been adapted for flow through vegetation. Predictions of the model compare satisfactorily with observations of the mean windspeed and (somewhat less satisfactorily) with the turbulent velocity variances in two very different canopies.  相似文献   

Tropical deforestation: Important processes for climate models   总被引：4，自引：0，他引：4  

A. Henderson-Sellers  R. E. Dickinson  M. F. Wilson 《Climatic change》1988,13(1):43-67

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Modal summation methods for structural dynamic computations     

P. Leger  E. L. Wilson 《地震工程与结构动力学》1988,16(1):23-27

The rate of convergence of the conventional mode superposition method can be significantly improved for systems subjected to relatively low frequency loadings by adding static correction terms to approximate the contribution of higher modes neglected by the use of a truncated eigenbasis. Two computational variants of the classical mode-acceleration method are developed for that purpose. It is recommended that the pseudo-static displacement correction vector should be computed from an expansion of the flexibility matrix in terms of the retained eigenvectors for actual computer implementation.  相似文献   

Editors’ preface     

John E. Moore  Clifford I. Voss  William E. Wilson 《Hydrogeology Journal》1994,2(1):3-5

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The role of bioindicators in estuarine management     

James G. Wilson 《Estuaries and Coasts》1994,17(1):94-101

Estuarine organisms can be considered three ways as bioindicators—first, as indicators of a defined set of environmental conditions, second, as indicators of contaminant loads on the system, and third, as indicators of the overall health of the system. By their very nature, estuarine organisms are eurytolerant and this, along with the various stratagems that have evolved to cope with the problems of life in estuaries results in a confusing picture for the estuarine manager. The recommended bioindicators for estuarine conditions are plankton; for contaminant loads, a range of species with different feeding types; and for system status, a eurytolerant species, such as the musselMytilus edulis for laboratory monitoring or a “target” species such as the clamMacoma balthica for field monitoring. However, it would be unwise to rely on a single indicator, and the recommendation is that the final choice, and preferably choices, be tailored to the desired goal.  相似文献