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51.
Stéphane Bodin Alexis Godet Virginie Matera Philipp Steinmann Jean Vermeulen Silvia Gardin Thierry Adatte Rodolfo Coccioni Karl B. Föllmi 《International Journal of Earth Sciences》2007,96(2):327-341
The Faraoni Level is a short-lived oxygen-deficient event that took place during the latest Hauterivian. In order to improve
our understanding of the palaeoenvironmental conditions that occurred during this event, we have analysed the contents of
several redox-sensitive trace elements (U, V, Mo, As, Co, Cd, Cu, Zn, Ni, Pb, Cr) from bulk limestone samples of late Hauterivian–early
Barremian age from three reference sections. U, V, Mo and As show consistent and significant enrichments during the Faraoni
event whereas the other redox-sensitive trace elements analysed here are not systematically enriched. In order to explain
this discrepant behaviour, we propose that the Faraoni Level was deposited during a period of anoxic conditions near the sediment–water
interface. The distinctive peaks in U, V, Mo and As contents are traceable throughout the three studied sections and represent
a good correlation tool which helps to identify the Faraoni Level and its equivalents in the western Tethyan realm and outside
of the Tethys. For example, a peak in U contents in upper Hauterivian sediments of the northwestern Pacific realm (ODP leg
185, site 1149) may well be an expression of the Faraoni event in this particular basin. 相似文献
52.
Virginie Garnier Daniel Ohnenstetter Gaston Giuliani 《Comptes Rendus Geoscience》2004,336(14):1245-1253
Ruby-bearing marbles from Nangimali, in the Azad-Kashmir, Pakistan, contain, besides phengite, different mica intergrowths: paragonite, phlogopite and aspidolite (sodium phlogopite). Both phlogopites, intimately linked and coexisting with paragonite, are fluorine rich, contrary to phengite and paragonite. F-enriched aspidolite is described for the first time. Phengite is either associated with phlogopite or could be isolated. The presence of aspidolite in the ruby-bearing marbles, together with other arguments such as salt solid inclusions and presence of anhydrite, suggest the implication of evaporites in the genesis of gem corundums. To cite this article: V. Garnier et al., C. R. Geoscience 336 (2004). 相似文献
53.
Airborne microphysical measurements and ground-based radar-reflectivity observations, collected at the near of a narrow cold frontal rainband during the FRONTS 87 experiment, are used to infer some characteristics of the precipitation: size-distribution, liquid or ice-water content, mass-weighted fallspeed, radar-reflectivity and relationships between pairs of these quantities. In the ice phase region, two different methods are proposed to calculate the radar reflectivity from the aircraft data. The influence of the choice of the ice particle type on the calculated quantities is discussed from the results of the first method. The second method is new: it is based upon the use of a roughness parameter estimated from the analysis of the two-dimensional particle images of ice precipitation. Although this method is tentative, it gives conclusive results for the two different flight levels studied here. 相似文献
54.
In the Nile deep‐sea fan, thin‐skinned deformation detaching on a layer of Messinian salt has generated an upslope to downslope progression from growth faults, to polygonal minibasins bounded by salt ridges, to buckle folds. Such progression is common in salt‐bearing passive margins, where gravity spreading of the salt–sediment system causes proximal thin‐skinned extension on the shelf and upper slope, and distal contraction along and in front of the lower slope. In the Eastern Nile deep‐sea fan, this structural progression seems to be restricted to a corridor bounded by NW–SE‐trending lineaments more than 200 km in length. These are associated with salt ridges and record strike–slip movements. In the absence of a large grid of deep‐penetrating seismic data accurately imaging the basement, different likely hypotheses have been advanced about the origin of this corridor: (1) it may result from possible deep‐seated tectonics related to the Rift of Suez, combined with salt‐related deformation or, (2) by complex interaction between the overburden's gravity spreading and pre‐existing pre‐Messinian paleo‐topographic features, particularly the possible buttressing effect of a seamount located North of the eastern Nile deep‐sea fan. In order to understand how this corridor could have been generated, we used a series of physical experiments to test the effect on three‐dimensional spreading of a sediment lobe of the following parameters: (1) active, crustal, oblique extension, (2) a dormant subsalt graben, (3) a passive buttress, such as a seamount and (4) complex paleo‐topographic features along the Egyptian margin affecting initial salt distribution. These experiments show that the presence of a distal buttress, combined with a complex Messinian topography best explain the complex deformational pattern observed in the eastern Nile deep‐sea fan. 相似文献
55.
Although high seas resources are being exploited, reciprocal legal obligations to protect its environment have not been met. Marine spatial planning (MSP) is clearly a practical way forward, particularly for the high seas, where non-spatial monitoring is difficult, and where data gaps obstruct conventional management approaches. To ensure the effective application of MSP in the high seas, however, some institutional reforms are necessary. This paper outlines the main hurdles, summarizes existing high seas spatial protections, presents an example of a high seas marine protected area that resulted through MSP, identifies three institutional priorities, and suggests three immediate steps. 相似文献
56.
Virginie Mamadouh 《GeoJournal》1999,48(2):133-144
The linguistic diversity in the European Union is generally viewed as an essential component of the European identity, but the linguistic regime of the EU institutions (with eleven official and working languages) is not undisputed. In addition, the upcoming enlargements will complicate greatly the continuation of the present practices as new Member States bring new official languages. As a result, the debate about possible reforms is likely to be boosted by the necessity to prepare EU institutions for further enlargment. The present regime of institutional multilingualism is criticised from different angles, resulting in three options for the future. In this paper the linguistic regime of EU institutions is discussed in relation to general ideas about the nature of this supranational political system. Supranationalism is treated here as a program to supersede nationalism. Three variants are distinguished: pacified nationalism, neo-nationalism and post-nationalism. The paper examines how these different visions of Europe shed different lights on the issue of multilingualism (in terms of communication, identity and power) and its institutionalisation in the linguistic regime of the core instituions of the European Union. Although the three models are compatible with several arrangements, they support or oppose them for different reasons. Besides, they differ regarding the significance of the linguistic regime of the EU institutions for the whole polity and their ability to steer linguistic practices. 相似文献
57.
Grid-group cultural theory: an introduction 总被引：2，自引：0，他引：2
Virginie Mamadouh 《GeoJournal》1999,47(3):395-409
This article offers an introduction to grid-group cultural theory (also known as grid-group analysis, Cultural Theory or theory
of socio-cultural viability), an approach that has been developed over the past thirty years in the work of the British anthropologists
Mary Douglas and Michael Thompson, the American political scientist Aaron Wildavsky, and many others. This assessment begins
with a presentation of the main claims of the theory, distinguishing two characteristic breads of grid-group cultural theory,
in the one it is conceived as a heuristic device, in the other it is seen as a full explanatory theory. This brief is followed
by a discussion of the typology generated by the theory. This includes a presentation of the two dimensions of sociality it
posits, the cultural map they produce, as well as the four (or five) cultural types derived from them and their designations.
The article proceeds with a discussion of key issues including the incorporation of other typologies (such as the one developed
to analyse myths of nature), the relations between cultures or rationalities and several methodological issues. Finally the
article introduces the contributions to this special issue of the GeoJournal.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
58.
Matthieu Waeles Virginie Tanguy Gaëtane Lespes Ricardo D. Riso 《Estuarine, Coastal and Shelf Science》2008,80(4):538-544
The frontal cascade ultrafiltration (UF) technique in conjunction with stripping chronopotentiometry (SCP) has been evaluated for determining the colloidal distribution of Cu, Pb and Cd in estuarine waters. Metallic concentrations in seven size fractions (0.45 μm–0.22 μm; 0.22 μm–300 kDa; 300–50 kDa; 50–30 kDa; 30–10 kDa; 10–5 kDa; <5 kDa) were determined with the aim to investigate their changes along the salinity gradient of the Penzé system (NW France). These data, completed by analysis of the total dissolved metals at 10 stations over the whole freshwater–seawater mixing zone, provided some insights in the removal and addition processes that affect Cu, Pb and Cd in estuaries. 相似文献
59.
Sandra Barbouteau Patrick Rasolofosaon Noalwenn Dubos‐Sallée Virginie Vassil Jean‐François Nauroy 《Geophysical Prospecting》2017,65(1):240-250
An alternative laboratory technique to measure the elastic constants of solid samples, based on the analysis of the cross‐correlation spectra of the vibratory response of randomly excited short solid cylinders, has been recently proposed. The aim of this paper is to check the ability of the technique called passive ultrasonic interferometry to monitor fluid substitution in different rock samples. Velocity variations due to fluid substitution are easily measured if the wave attenuation in the fluid‐saturated rock is not too large (typically in rocks with few cracks or microfractures). The experimental results are in agreement with the predictions of Biot–Gassmann poroelastic theory. The effect of substituting water with a stiffer saturating fluid, such as ethylene glycol, is to increase the overall bulk modulus of the rock, without any substantial effect on shear modulus. Furthermore, the experimental results compare well with those obtained independently with conventional pulse‐transmission technique using ultrasonic transducers. However, the measured pulse‐transmission bulk moduli are slightly larger than the corresponding measured ultrasonic interferometry moduli, with the deviation increasing with increasing fluid viscosity. This can be explained by dispersion due to wave‐induced flow of the viscous fluid since pulse‐transmission experiments involve higher frequencies than ultrasonic interferometry experiments. 相似文献
60.
Ana Colaço Catarina Prieto Ana Martins Miguel Figueiredo Virginie Lafon Margarida Monteiro Narcisa M. Bandarra 《Marine environmental research》2009,67(3):146-152
Specimens of the hydrothermal mussel Bathymodiolus azoricus collected in Menez Gwen hydrothermal vent field (NE Atlantic) during 2002–2003 were examined for feeding patterns variations through three seasons. The fatty acid profile and lipid classes of the mussels were studied, together with the MODIS/AQUA-derived near-surface chlorophyll a to test the hypothesis that surface productivity might be related to the feeding patterns of this species. The lipid levels showed pronounced seasonal fluctuations with the highest values occurring in January and August. Seasonal variations in lipid classes and fatty acid composition of neutral and polar lipids in the mussels are presented. Differences in the fatty acid profile of lipid classes in different seasons suggest that the higher energy requirements in summer and winter were supplied by bacterial biomarkers ω7 MUFA (monounsaturated fatty acids), whereas ω6 PUFA (polyunsaturated fatty acids) and NMI (non-methylene-interrupted) fatty acids predominated during the spring. The MODIS/AQUA data show marked seasonal variability and an anomalous peak during January of 2003, although this cannot be directly linked to lipid composition variation. 相似文献