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71.
Jean Michel Vouillamoz Rémi Valois Sambo Lun Delphine Caron Ludovic Arnout 《Hydrogeology Journal》2016,24(1):195-209
Since the end of the Cambodian Civil War in 1998, the population of the Oddar Meanchey province has drastically increased despite the lack of adequate infrastructure, including basic amenities such as drinking-water supply. To improve the access to drinking water, governmental and aid agencies have focussed on drilling shallow boreholes. The use of groundwater for irrigation is also a growing concern to cope with the occasional late arrival of the rainy season or to produce food during the dry season. Since the groundwater resource in the province has not been documented, a 4-year study was undertaken (2011–2014), aiming to estimate the capability of groundwater to supply domestic needs and supplementary irrigation for rice production. Aquifer properties were estimated by combined use of hydrogeological techniques with the geophysical magnetic resonance sounding method. Groundwater storage and recharge were estimated based on new developments in the application of the geophysical method for quantifying specific yield. The median groundwater storage of the targeted sandstone aquifer is 173 mm, the recharge is diffuse and annually ranges from 10 to 70 mm, and the transmissivity is low to medium. Simulations of pumping indicate that the aquifer can easily supply 100 L of drinking water per capita daily, even considering the estimated population in 2030. However, the shallow aquifer can generally not deliver enough water to irrigate paddy fields of several hectares during a 2-month delay in the onset of the monsoon. 相似文献
72.
Marchesi Claudio; Garrido Carlos J.; Bosch Delphine; Proenza Joaquin A.; Gervilla Fernando; Monie Patrick; Rodriguez-Vega Antonio 《Journal of Petrology》2007,48(9):1813-1840
We present whole-rock major- and trace-element and Nd–Sr–Pbradiogenic isotope data for Cretaceous igneous suites from easternCuba. These rocks are related to the Greater Antilles paleo-islandarc magmatism and have three different igneous styles. Group1 consists of tholeiitic basalts and rare basaltic andesitesthat have normal mid-ocean ridge basalt (N-MORB)-like compositionssimilar to those found in back-arc basin basalts (TiO2 = 1·2–2·9wt%; La/Yb(N) = 0·7–0·9, Th/Nb = 0·06–0·08,and initial 208Pb/ 204Pb = 37·65–37·74).Group 2 comprises basaltic and rare basaltic andesitic subvolcanicdykes with major- and trace-element and isotopic compositionssimilar to those of island arc tholeiites (TiO2 = 0·7–1·4wt%; La/Yb(N) = 0·6–0·9, Th/Nb = 0·06–0·68,and initial 208Pb/ 204Pb = 37·74–38·25).Group 3 is composed of low-Ti (TiO2 = 0·3–0·9wt%) calcalkaline igneous rocks that have an unambiguous subduction-relatedcharacter (La/Yb(N) = 1·1–5·0, Th/Nb = 0·35–1·55,and initial 208Pb/ 204Pb = 37·94–38·39).The parental magmas of the three groups formed by variable meltingdegrees (< 5–25%) of spinel lherzolite, with more depletedmantle sources for Groups 2 and 3 than Group 1. The trace-elementand radiogenic isotope compositions of primitive Group 3 samplesare strongly bimodal. One subgroup of samples is characterizedby low Ta/Yb (0·02–0·03) and Th/La (0·10–0·13),slightly subchondritic Nb/Ta (13·3–17·3),and relatively high initial 206Pb/204Pb (18·57–18·62)and Nd (7·6–9·4). The remaining primitiveGroup 3 samples have higher Ta/Yb (0·06–0·11)and Th/La (0·24–0·32), and highly subchondriticNb/Ta (7·6–9·1), coupled with lower initial206Pb/204Pb (18·24–18·29) and Nd (3·4–5·5).These signatures were induced by two distinct slab componentsthat mainly reflect the contributions of Cretaceous Atlanticmarine and North American continental sediments, respectively.Nb/Ta in the first subgroup was influenced by melting of rutile-bearingsubducted crust, whereas in the second it was inherited fromrecycled continental sediments. The involvement of Atlanticand North American sediments in Cuban Cretaceous magmatism indicatesthat the Proto-Caribbean (North American-Proto Atlantic) lithospheresubducted beneath the Greater Antilles arc during the Late Cretaceous(pre-Campanian), consistent with geotectonic models involvingonset of SW-dipping subduction beneath the Greater Antillespaleo-arc during the Aptian. The variable mantle source depletionand magnitude of the subduction component probably reflect differentsettings across the arc, from the arc front to a back-arc spreadingridge. KEY WORDS: eastern Cuba; Greater Antilles paleo-island arc; mantle source depletion; Nb/Ta fractionation; slab component 相似文献
73.
One way to address the assessment of strategies to control wave overtopping at seawalls and related coastal defence structures is to make use of Cost-Benefit Analysis. The institutional context in which Cost-Benefit Analysis takes place influences decisions on the types of values that are taken into consideration and the subsequent selection of valuation methods. We suggest to consider Cost-Benefit Analysis in a broad institutional framework when decisions are to be made on coastal defence strategies. It is argued that the institutional context provides the rules of the game on how a balance can be found between social, economic and ecologic functions of projects that protect societies against overtopping. 相似文献
74.
The degradation of acyclic petroleum hydrocarbons was studied during a 24-month experiment in Mediterranean coastal sediments (Gulf of Fos). Sediment cores entirely contaminated with oil (Arabian Light Crude Oil) were incubated in situ. The use of conservative tracers of sediment's particles reworking (luminophores) allowed the distinction of the reworked layer from the anoxic deeper sediments. Using the 17α,21βC30 hopane (C30H) as an inert internal reference, we could demonstrate that, after 24 months of experiment, acyclic petroleum hydrocarbons can be degraded under natural anaerobic conditions. The reactivity of individual alkanes appeared to depend on their chemical structure. To cite this article: D. Massias et al., C. R. Geoscience 335 (2003).To cite this article: D. Massias et al., C. R. Geoscience 335 (2003). 相似文献
75.
Ethnic groups’ response to the 26 December 2004 earthquake and tsunami in Aceh, Indonesia 总被引：4，自引：4，他引：0
Jean-Christophe Gaillard Elsa Clavé Océane Vibert Azhari Dedi Jean-Charles Denain Yusuf Efendi Delphine Grancher Catherine C. Liamzon Desy Rosnita Sari Ryo Setiawan 《Natural Hazards》2008,47(1):17-38
The 26 December 2004 earthquake and tsunami unfairly hit the different ethnic groups of Aceh, Indonesia. About 170,000 Acehnese
and Minangkabau people died in the Northern tip of Sumatra while only 44 Simeulue people passed away in the neighbouring Simeulue
island located near the earthquake epicentre. Such a difference in the death toll does not lie in the nature of the hazard
but in different human behaviours and ethnic contexts. The present study draws on a contextual framework of analysis where
people’s behaviour in the face of natural hazards is deeply influenced by the cultural, social, economic and political context.
Questionnaire-based surveys among affected communities, key informant interviews and literature reviews show that the people
of Simeulue detected the tsunami very early and then escaped to the mountains. On the other hand, Acehnese and Minangkabau
people, respectively in the cities of Banda Aceh and Meulaboh, did not anticipate the phenomenon and were thus caught by the
waves. The different behaviours of the victims have been commanded by the existence or the absence of a disaster subculture
among affected communities as well as by their capacity to protect themselves in facing the tsunami. People’s behaviours and
the capacity to protect oneself can be further tracked down to a deep tangle of intricate factors which include the armed
conflict that has been affecting the province since the 1970s, the historical and cultural heritage and the national political
economy system. This paper finally argues that the uneven impact of the 26 December 2004 earthquake and tsunami in Aceh lies
in the different daily life conditions of the ethnic groups struck by the disaster. 相似文献
76.
Vincent?TrincalEmail author Martine?Buatier Delphine?Charpentier Brice?Lacroix Pierre?Lanari Pierre?Labaume Abdeltif?Lahfid Torsten?Vennemann 《Contributions to Mineralogy and Petrology》2017,172(9):78
In orogens, shortening is mainly accommodated by thrusts, which constitute preferential zones for fluid–rock interactions. Fluid flow, mass transfer, and mineralogical reactions taking place along thrusts have been intensely investigated, especially in sedimentary basins for petroleum and uranium research. This study combines petrological investigations, mineralogical quantifications, and geochemical characterizations with a wide range of analytical tools with the aim of defining the fluid properties (nature, origin, temperature, and redox) and fluid–host rock interactions (mass transfers, recrystallization mechanisms, and newly formed synkinematic mineralization) in the Pic-de-Port-Vieux thrust fault zone (Pyrenees, Spain). We demonstrate that two geochemically contrasted rocks have been transformed by fluid flow under low-grade metamorphism conditions during thrusting. The hanging-wall Triassic red pelite was locally bleached, while the footwall Cretaceous dolomitic limestone was mylonitized. The results suggest that thrusting was accompanied by a dynamic calcite recrystallization in the dolomitic limestone as well as by leaching of iron via destabilization of iron oxides and phyllosilicate crystallization in the pelite. Geochemical and physical changes highlighted in this study have strong implications on the understanding of the thrust behavior (tectonic and hydraulic), and improve our knowledge of fluid–rock interactions in open fluid systems in the crust. 相似文献
77.
Geostatistical estimations of the hydraulic conductivity field (K) in the Carrizo aquifer, Texas, are performed over three regional domains of increasing extent: 1) the domain corresponding
to a three-dimensional groundwater flow model previously built (model domain); 2) the area corresponding to the 10 counties
encompassing the model domain (County domain), and; 3) the full extension of the Carrizo aquifer within Texas (Texas domain).
Two different approaches are used: 1) an indirect approach where transmissivity (T) is estimated first and K is retrieved through division of the T estimate by the screen length of the wells, and; 2) a direct approach where K data are kriged directly. Due to preferential well screen emplacement, and scarcity of sampling in the deeper portions of
the formation (> 1 km), the available data set is biased toward high values of hydraulic conductivities. Kriging combined
with linear regression, simple kriging with varying local means, kriging with an external drift, and cokriging allow the incorporation
of specific capacity as secondary information. Prediction performances (assessed through cross-validation) differ according
to the chosen approach, the considered variable (log-transformed or back-transformed), and the scale of interest. For the
indirect approach, kriging of log T with varying local means yields the best estimates for both log-transformed and back-transformed variables in the model domain.
For larger regional scales (County and Texas domains), cokriging performs generally better than other kriging procedures when
estimating both (log T)∗ and T∗. Among procedures using the direct approach, the best prediction performances are obtained using kriging of log K with an external drift. Overall, geostatistical estimation of the hydraulic conductivity field at regional scales is rendered
difficult by both preferential well location and preferential emplacement of well screens in the most productive portions
of the aquifer. Such bias creates unrealistic hydraulic conductivity values, in particular, in sparsely sampled areas. 相似文献
78.
Antoine Rabatel Vincent Jomelli Philippe Naveau Bernard Francou Delphine Grancher 《Comptes Rendus Geoscience》2005,337(15):1311-1322
Fluctuations of the Charquini glaciers (Cordillera Real, Bolivia) have been reconstructed for the Little Ice Age (LIA) from a set of 10 moraines extending below the present glacier termini. A lichenometric method using the Rhizocarpon geographicum was used to date the moraines and reconstruct the main glacier fluctuations over the period. The maximum glacier extent occurred in the second half of the 17th century, followed by nearly continuous retreat with three interruptions during the 18th and the 19th centuries, marked by stabilisation or minor advances. Results obtained in the Charquini area are first compared with other dating performed in the Peruvian Cordillera Blanca and then with the fluctuations of documented glaciers in the Northern Hemisphere. Glacier fluctuations along the tropical Andes (Bolivia and Peru) were in phase during the LIA and the solar forcing appears to be important during the period of glacier advance. Compared with the Northern Hemisphere mid-latitudes, the major advance observed on these glaciers during the first half of the 19th century is not present in the tropical Andes. This discrepancy may be due to regional scale climate variations. To cite this article: A. Rabatel et al., C. R. Geoscience 337 (2005). 相似文献
79.
Robert Barouki Manolis Kogevinas Karine Audouze Kristine Belesova Ake Bergman Linda Birnbaum Sandra Boekhold Sebastien Denys Celine Desseille Elina Drakvik Howard Frumkin Jeanne Garric Delphine Destoumieux-Garzon Andrew Haines Anke Huss Genon Jensen Spyros Karakitsios Jana Klanova Iida-Maria Koskela Francine Laden Paolo Vineis 《Chemie der Erde / Geochemistry》2010
The outbreak of COVID-19 raised numerous questions on the interactions between the occurrence of new infections, the environment, climate and health. The European Union requested the H2020 HERA project which aims at setting priorities in research on environment, climate and health, to identify relevant research needs regarding Covid-19. The emergence and spread of SARS-CoV-2 appears to be related to urbanization, habitat destruction, live animal trade, intensive livestock farming and global travel. The contribution of climate and air pollution requires additional studies. Importantly, the severity of COVID-19 depends on the interactions between the viral infection, ageing and chronic diseases such as metabolic, respiratory and cardiovascular diseases and obesity which are themselves influenced by environmental stressors. The mechanisms of these interactions deserve additional scrutiny. Both the pandemic and the social response to the disease have elicited an array of behavioural and societal changes that may remain long after the pandemic and that may have long term health effects including on mental health. Recovery plans are currently being discussed or implemented and the environmental and health impacts of those plans are not clearly foreseen. Clearly, COVID-19 will have a long-lasting impact on the environmental health field and will open new research perspectives and policy needs. 相似文献
80.
Damien Daval Roland Hellmann Delphine Tisserand François Guyot 《Geochimica et cosmochimica acta》2010,74(9):2615-5525
Measurements of the dissolution rate of diopside (r) were carried out as a function of the Gibbs free energy of the dissolution reaction (ΔGr) in a continuously stirred flow-through reactor at 90 °C and pH90 °C = 5.05. The overall relation between r and ΔGr was determined over a free energy range of −130.9 < ΔGr < −47.0 kJ mo1−1. The data define a highly non-linear, sigmoidal relation between r and ΔGr. At far-from-equilibrium conditions (ΔGr ? −76.2 kJ mo1−1), a rate plateau is observed. In this free energy range, the rates of dissolution are constant, independent of [Ca], [Mg] and [Si] concentrations, and independent of ΔGr. A sharp decrease of the dissolution rate (∼1 order of magnitude) occurs in the transition ΔGr region defined by −76.2 < ΔGr ? −61.5 kJ mo1−1. Dissolution closer to equilibrium (ΔGr > −61.5 kJ mo1−1) is characterised by a much weaker inverse dependence of the rates on ΔGr. Modeling the experimental r-ΔGr data with a simple classical transition state theory (TST) law as implemented in most available geochemical codes is found inappropriate. An evaluation of the consequences of the use of geochemical codes where the r-ΔGr relation is based on basic TST was carried out and applied to carbonation reactions of diopside, which, among other reactions with Ca- and Mg-bearing minerals, are considered as a promising process for the solid state sequestration of CO2 over long time spans. In order to take into account the actual experimental r-ΔGr relation in the geochemical code that we used, a new module has been developed. It reveals a dramatic overestimation of the carbonation rate when using a TST-based geochemical code. This points out that simulations of water-rock-CO2 interactions performed with classical geochemical codes should be evaluated with great caution. 相似文献