Groundwater protection in fractured media: a vulnerability-based approach for delineating protection zones in Switzerland   总被引：1，自引：0，他引：1  

Alain Pochon  Jean-Pierre Tripet  Ronald Kozel  Benjamin Meylan  Michael Sinreich  François Zwahlen 《Hydrogeology Journal》2008,16(7):1267-1281

A vulnerability-based approach for delineating groundwater protection zones around springs in fractured media has been developed to implement Swiss water-protection regulations. It takes into consideration the diversity of hydrogeological conditions observed in fractured aquifers and provides individual solutions for each type of setting. A decision process allows for selecting one of three methods, depending on the spring vulnerability and the heterogeneity of the aquifer. At the first stage, an evaluation of spring vulnerability is required, which is essentially based on spring hydrographs and groundwater quality monitoring. In case of a low vulnerability of the spring, a simplified method using a fixed radius approach (“distance method”) is applied. For vulnerable springs, additional investigations must be completed during a second stage to better characterize the aquifer properties, especially in terms of heterogeneity. This second stage includes a detailed hydrogeological survey and tracer testing. If the aquifer is assessed as slightly heterogeneous, the delineation of protection zones is performed using a calculated radius approach based on tracer test results (“isochrone method”). If the heterogeneity is high, a groundwater vulnerability mapping method is applied (“DISCO method”), based on evaluating discontinuities, protective cover and runoff parameters. Each method is illustrated by a case study.  相似文献   

Analysis of nocturnal air temperature in districts using mobile measurements and a cooling indicator     

Leconte  François  Bouyer  Julien  Claverie  Rémy  Pétrissans  Mathieu 《Theoretical and Applied Climatology》2017,130(1-2):365-376

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Modeling of the transport and deposition of tungsten in the scheelite-bearing calc-silicate gneisses of the Montagne Noire,France     

François Gibert  Bernard Moine  Jacques Schott  Jean-Louis Dandurand 《Contributions to Mineralogy and Petrology》1992,112(2-3):371-384

Scheelite-bearing calc-silicate gneisses (CSG) oceur in the Montagne Noire within a series of dominant micaschists. Detailed petrographical and mineralogical studies reveal three successive stages of metamorphism and hydrothermal alteration: (1) stage 1, a regional metamorphism at 550°C and 4.5 kb where no mineralization is formed; (2) stage 2a, a hydrothermal alteration at 500 to 450°C and 4 to 3 kb which is characterized by an intense sericitization of feldpars and deposition of Sn in Sn-bearing cale-silicates; and (3) stage 2b, a hydrothermal alteration characterized by the crystallization of idocrasegrossular in CSG with concomittant precipitation of scheelite. Tungsten was transported through the micaschist environment and deposited as scheelite only in the CSG of stage 2b at relatively low pressures. To characterize the mechanism of tungsten transport, tungsten speciation at high P-T and scheelite solubility in aqueous solations buffered by the CSG and by the micaschists assemblages were calculated. It was found that H₂WO ₀ ⁴ , HWO _- ⁴ and WO _2- ⁴ are the dominant tungsten aqueous species in H₂O–NaCl (one molal) solutions at 500°C and 2–4 kb. Calculations also indicate that scheelite deposition is controlled by decreasing pressure and increasing activity of aqueous calcium in this system. This is consistent with the petrographical and mineralogical observations. The consequences of the presence of volatiles (N₂, CH₄, CO₂) in the regional fluids were examined by determining the effect of N₂ on tungsten speciation and scheelite solubility. The addition of N₂ (up to 10 mol%) to the mineralizing fluids results in a marked increase in H₂WO ₀ ⁴ and HWO _- ⁴ concentrations relative to WO _2- ⁴ and in a large decrease of scheelite solubility. This mechanism favours scheelite precipitation and accounts for the commonly observed association of W (and Sn) deposits with graphitic series generating mixed volatiles fluids.  相似文献   

Mesoscale SST–wind stress coupling in the Peru–Chile current system: Which mechanisms drive its seasonal variability?     

Vera Oerder  François Colas  Vincent Echevin  Sebastien Masson  Christophe Hourdin  Swen Jullien  Gurvan Madec  Florian Lemarié 《Climate Dynamics》2016,47(7-8):2309-2330

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Does carbon finance make a sustainable difference? Hydropower expansion and livelihood trade‐offs in the Red River valley,Yunnan Province,China          下载免费PDF全文

Jean‐François Rousseau 《Singapore journal of tropical geography》2017,38(1):90-107

The Kyoto Protocol's Clean Development Mechanism (CDM) is a carbon credit trading scheme intended to reduce anthropogenic greenhouse gas emissions and promote ‘sustainable development’. Hundreds of CDM‐sponsored hydroelectric dams have been constructed in southwest China's Yunnan Province, where carbon finance contributes substantial financial incentives to hydropower expansion. This article investigates whether riparian Handai farmers settled near the Madushan hydropower plant on the Chinese section of Red River have experienced positive outcomes from this project's participation in the CDM. I assess how Handai individuals' access to core livelihood assets has been modified following dam completion and probe how the CDM reconfigures scalar relations among the various stakeholders involved in hydropower governance in Yunnan. Though the CDM facilitates hydropower expansion, it fails to produce development that is more sustainable than ‘business as usual’ from a local perspective. Rather, the CDM consolidates hydropower governance in the same way as it unfolded in Yunnan before the province became an active participant in this scheme. The CDM also facilitates a national development campaign fostering specific socio‐economic modernization patterns in China's western provinces.  相似文献   

The magnetic anisotropy of hematite bearing rocks     

Hartmut Porath  François H. Chamalaun 《Pure and Applied Geophysics》1966,64(1):81-88

Summary The high field torque curves of hematite bearing rocks are not caused by directional differences in the energy of magnetization to saturation, but rather by the couple between the ferromagnetic moment and the applied field. An expression, derived for the high field torque curve of a single crystal of hematite, whose basal plane makes an arbitrary angle with the plane of rotation of the applied field, is found to be in excellent agreement with experiment. Furthermore it is shown that the Fourier spectrum of hematite bearing rocks should in general contain significant higher harmonics and that therefore the high field method is not particularly suitable for determining the preferred crystalline alignment of hematite bearing rocks.  相似文献   

Upper cretaceous and paleogene sediments from the Northern Kerguelen Plateau     

François Fröhlich  Emmanuelle Wicquart 《Geo-Marine Letters》1989,9(3):127-133

Upper Cretaceous and Paleogene pelagic sediments sampled from the Northern Kerguelen Plateau during cruise MD35 of theMarion Dufresne are described and correlated with the Late Paleogene sequence drilled at site ODP 737 (Leg 119). Taking into account geophysical data obtained by the cruise MD26, a Lower Cretaceous age is computed for the unsampled acoustic basement. A major tectonic/volcanic event in the Late Paleogene, related to rifting, gave rise to a marked unconformity and hiatus termed the “Acoustic Discordance.” Tertiary sediment facies changes were strongly influenced by the evolution of the Antarctic environment.  相似文献   

The Var turbidite system (Ligurian Sea, northwestern Mediterranean)—morphology, sediment supply, construction of turbidite levee and sediment waves: implications for hydrocarbon reservoirs     

Sébastien Migeon  Thierry Mulder  Bruno Savoye  Françoise Sage 《Geo-Marine Letters》2006,26(6):361-371

The Var turbidite system is a small sandy system located in the Ligurian Basin. It was deposited during the Pliocene-Quaternary in a flat-floored basin formed during the Messinian salinity crisis. The system was fed through time by the Var and Paillon canyons that connect directly to the Var and Paillon rivers. It is still active during the present sea-level highstand. Two main mechanisms are responsible for gravity-flow triggering in the Var turbidite system: (1) mass-wasting events affect mainly the upper part of the continental slope, in areas where volumes of fresh sediment delivered by rivers are highest, and result from the under-consolidation state of slope sediments and earthquakes, and (2) high-magnitude river floods resulting from melting of snow and convective rainfall during fall and spring seasons, and generating hyperpycnal turbidity currents at river mouths when the density of freshwater transporting suspended particles exceeds that of ambient seawater. Failure- and flood-induced gravity flows are involved through time in the construction of the Var Sedimentary Ridge, the prominent right-hand levee of the Var system, and sediment waves. Processes of construction of both the Var Ridge and sediment waves are closely connected. Sandy deposits are thick and abundant in the eastern (downchannel) part of the ridge. Their distribution is highly constrained by the strong difference of depositional processes across the sediment waves, potentially resulting through time in the individualization of large and interconnected sand bodies.  相似文献   

Significance of gabbronorite occurrence in the crustal section of the Semail ophiolite     

Boudier  Françoise  Godard  Marguerite  Armbruster  Catherine 《Marine Geophysical Researches》2000,21(3-4):307-326

The eastern end of the Haylayn massif exposes a complex paleoridge structure interpreted as the tip of a northwestward propagating segment (Nicolas et al., this issue). The area, revisited from a petrostructural and geochemical viewpoint, offers the most documented exposures of the association of olivine gabbros and gabbronorites in Oman (Juteau et al., 1988). Gabbronorites were injected while the main gabbro unit was deforming in the magmatic state. Both units do not differ chemically, except for the SiO₂ enrichment of the orthopyroxene-rich gabbros relative to olivine-gabbro. In addition, they display the same trace element signature, which implies the same parent magma for both units. The extension of the stability field of orthopyroxene is assigned to increase of oxygen fugacity due to hydration. The source of hydration is the ridge axis hydrothermal circulation, suggesting hydrothermal/magma interaction at temperatures above the gabbro solidus. The distribution of gabbronorites at the scale of the entire ophiolite suggests a relation with ridge tectonics where high-T conditions of hydrothermal-magmatic interaction are met. Such conditions are met when propagating segments rotate the structures of the dying magma chamber.  相似文献   

Reconstruction of environmental histories to investigate patterns of larval radiated shanny (Ulvaria subbifurcata) growth and selective survival in a large bay of Newfoundland     

Baumann  Hannes; Pepin  Pierre; Davidson  Fraser J.M; Mowbray  Fran; Schnack  Dietrich; Dower  John F 《ICES Journal of Marine Science》2003,60(2):243-258

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