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1.
Natural Resources Research - This contribution proposes a spatially weighted factor analysis (SWFA) to recognize effectively the underlying mineralization-related feature(s) in geochemical signals....  相似文献   
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The Southeast Basin of France is the thickest onshore French sedimentary basin which contains locally as much as 10 km of Mesozoic-Cenozoic sediment. Basin development occurred in several stages between late Carboniferous and late Cretaceous times. Partial tectonic inversion took place during two compressive events, the so-called ‘Pyrenean’ and ‘Alpine’ phases of late Cretaceous-early Tertiary and late Tertiary ages respectively. They are separated by an intervening stretching event of Oligocene age, which further south resulted in the opening of the western Mediterranean oceanic basin. As a result of this complex tectonic history, structural traps were difficult to image on the seismic data shot during the first phase of exploration prior to 1980. Oil and gas natural seeps, and shows in several wells, indicate that some petroleum systems are, or have been active, at least in some places.The present erosional western margin of the basin is more or less superimposed on the initial Triassic-Jurassic margin. Margin subsidence and Tertiary inversion are discussed using regional sections on which the polyphase history of the entire basin is well shown. These sections are located on three major segments where the Mesozoic margin is either partly preserved (Ardèche), or has been partly inverted in late Tertiary times (Vercors-Chartreuse), or has been completely inverted in early Tertiary times (Corbières-eastern Pyrenees). 1-D ‘Genex’ basin modelling on the Ardèche segment, and 2-D ‘Thrustpack’ structural-maturity modelling in the Vercors-Chartreuse segment are used to further assess the remaining petroleum plays.  相似文献   
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Ocean Science Journal - We evaluated the influence of areas with dissimilar upwelling intensity along the Humboldt Current System on the morphological variation of the economically important sea...  相似文献   
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Microporosity may account for a significant part of the total porosity of Cretaceous limestone reservoirs of the Middle East. In these microporous facies porosity is moderate to excellent (up to 35%) while permeability is poor to moderate (up to 190 mD). Micritic limestones also may form dense layers with very low porosity and permeability values.Micritic samples were collected from three fields of the Habshan and Mishrif Formations, to examine the spatial relationship with their porosity, permeability and pore throat radius distributions. Two key parameters of the micritic particles are studied using scanning electron microscopy: their morphology (shape and inter-crystal contacts), and their crystallometry.Results reveal that micrite matrixes can be subdivided into three petrophysical classes. Class C (strictly microporous limestones with coarse punctic-to-partially coalescent micrites) is made up of coarse (>2 μm) polyhedral to rounded micritic crystals, it has good to excellent porosity (8-28%), poor to moderate permeability (0.2-190 mD) and a mean pore threshold radius of more than 0.5 μm. The class C is usually observed in rudist shoal facies where relatively high hydrodynamic energy disfavoured deposition of the finer micritic crystals. It also developed within meteoric leaching intervals below exposure surfaces. Class F (strictly microporous limestones with fine punctic-to-partially coalescent micrites) is composed of fine (<2 μm) polyhedral to rounded micrites with poor to excellent porosity (3-35%), but permeability values of less than 10 mD and a mean pore threshold radius of less than 0.5 μm. It is mostly observed in sediments deposited in a low energy muddy inner platform setting. Class D (strictly microporous mud-dominated facies with compact anhedral to fused dense micrites) comprises subhedral to anhedral crystals with sutured contacts forming a dense matrix. It has very low porosity and permeability. Class D is only found in low energy muddy inner platform facies and forms inter-reservoir or caps rock layers in close association with stylolites and clay contents that usually exceed 10%.  相似文献   
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Fluid and solid transfer in mud volcanoes show different cyclic phases of activity, including catastrophic events and periods of relative quiescence characterized by moderate activity. This is notably well-shown by the compilation of historical data onshore Trinidad. It appears that each eruptive mud volcano has its own period of catastrophic activity, and this period is variable from one volcano to another. The frequency of the eruptions seems essentially controlled by local pressure regime within the sedimentary pile. The dynamics of expulsion of the mud volcanoes during the quiescent phases has been studied with the help of temperature measurements within the mud conduits. The mud temperature in these conduits is notably concurrently controlled by the gas flux (endothermic gas depressurizing induces a cooling effect), and by the mud flux (mud is a vector for convective heat transfer). Complex temperature distribution was observed in large conduits and pools. Especially in the bigger pools, the temperature distribution characterizes convective cells with an upward displacement of mud above the deep outlet, and ring-shaped rolls associated with the burial of the mud on the flanks of the pools. In tube-like shaped narrow conduits, the temperature is more regular, but we observed different types of profiles, with either downward increasing or decreasing temperatures. Near constant to even negative gradients compared to the general temperature gradient are typical for very dynamic fluid systems. The temperature profiles varied from one place to another, as well as over time. The temperatures measured within the conduits and their base show that the fluid flow is not constant but highly variable through short time-periods. We observed locally a significant daily change of the temperature of the expelled mud which shows also that the mud flux is changing very rapidly due to the migration dynamics of the mud in fracture systems. We also observed very short time-period cyclic variations with a frequency of several minutes. These high frequencies temperature changes could be related to the dynamics of two-phase flows (gas and mud) through the mud volcano conduits.  相似文献   
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Abstract

Metamorphosed mafic rocks probably corresponding lo ancient basaltic ashes (meta-tuffs) have been discovered in Kastern Vanoise. These rocks are interbedded within the Maastrichtian-paleocene formations of the Grande Motte unit. Their geochemícal characteristics are consistent with a within-plate affinity. A remote origin of these materials, as airfall ashes, is possible. These volcanic rocks arc coeval with eruptive alkaline products known is the Southern Alps. They have formed in a local extensional and/or strike-slip environment involving the internal Alpine realms around the Cretaceous-Tertiary boudary.  相似文献   
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Résumé

L’étude des Schistes lustrés du transect alpin de la Vanoise a permi de préciser les modalités et la chronologie des événements tectoniques précoces enregistrés dans les Alpes occidentales et ainsi de souligner (|ue l’évolution alpine crétacé-tertiaire ne peut s’interpréter comme un simple continuum de déformations compressives. Doivent être distinguées trois étapes majeures : (1 ) un stade précoce crétacé « moyen » à supérieur responsable de l’enfouissement profond d’unités de la marge nord-léthysicnne et de la fermeture du domaine océanique téthysien alpin. Cet événement se matérialise notamment par des enregistrements tectono-sédimentaires (flyschs à blocs d’ophiolilcs) pendant lu fermeture et aboutit à l’enfouissement d’unités océaniques durant le Sénonien dans des conditions de haute pression. Cet événement se corrèle avec la rotation intra-erétaeé supérieur de l’lbérie ; (2 ) un stade maas-trichtien-paléocène durant lequel aucune évidence de déformations compressives n’est connu, mais durant lequel, en revanche, on enregistre des manifestations de magmutisme de type intraplaque caractérisant une tectonique extensive et/ou décrochante. C’est durant cette période que l’on assiste à la suhsidence du bassin des flyschs à Ilelminthoïdes et que, conjointement, l’on enregistre les vitesses de surreetion les plus fortes des roches HP-UT métamorphisées durant le Crétacé supérieur; (3) un stade éocène à actuel, responsable de l’édification et de la déformation de l’édifice actuel se corré-lant avec la forte convergence Europe-Afrique qui s’enregistre depuis l’Eocène (collision tertiaire).  相似文献   
10.
Summary A dispersion model is proposed to predict the continuous vertical variation of the dispersion parameters y and z in case of hot pollutant release to the atmosphere. In such a case, the plume rises far above the ground and is subject to varying levels of turbulence. The framework in this paper can be divided into three approaches: (1) determination of the eddy diffusivitiesK y (z, y ) andK z (z, z ) as functions of height above ground and plume dimensions, (2) determination of both the plume rise and its vertical velocity using a modified version of Brigg's formula, and (3) numerical solution of actual problems with buoyant plumes at each time step. The model results have been applied to a case of pollutant release from fire destruction of a chemical storehouse roof.With 15 Figures  相似文献   
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