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Literatura académica sobre el tema "Rapport isotopique 87Sr/86Sr"
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Tesis sobre el tema "Rapport isotopique 87Sr/86Sr"
Nasr, Emna. "Signatures inorganiques et isotopiques combinées pour la discrimination de l'origine géographique de l'huile d'olive". Electronic Thesis or Diss., Pau, 2022. http://www.theses.fr/2022PAUU3004.
Texto completoThe globalization of the food industry has raised consumer interest in the geographical origin and the quality of food products. The global increase in food production and consumption, however, has led to fraudulent practices spreading. It threatens both the health of consumers and the economic balance of the food industry, which suffers huge financial loss every year. Olive oil is one of the most adulterated food products. As a result, a large array of analytical strategies was proposed for the geographical authentication of olive oil. The most reliable approaches that have demonstrated promising results for the geographical traceability of food products were based on the multi-elemental and isotopic fingerprinting. Nevertheless, trace elements, initially found at low to critically low concentrations in olive oil, are dissolved in a complex lipid matrix and thus the samples introduction in plasma-based instruments and the precise measurements of chemical components are challenging. This study presents a reliable analytical approach based on a three dimensional geographic information: (1) the mineral composition of the soil through the analysis of trace elements; (2) the geological background through the analysis of Sr isotopic composition; and (3) the pedo-climatic context through the determination of stable isotopes of carbon in olive oils. First, the trace elements were quantified in olive oils from Tunisia, Spain and France with high precision and accuracy by quadrupole ICP-MS following an optimized analytical procedure. The elemental concentrations combined with chemometrics allowed to classify olive oils according to their geographical provenance. Subsequently, an innovative method was developed and successfully applied for the quantitative extraction of Sr from olive oil matrix and accurate measurement of 87Sr/86Sr isotopic ratio by MC-ICP-MS. The conservation of 87Sr/86Sr isotopic ratios during the transfer of Sr from the soil to the plant and during olive oil extraction was demonstrated. The results were correlated with the geological characteristics of the bedrocks and thus highlighted that Sr isotopic composition of olive oil can be used as a reliable tool for fingerprinting olive oil geographic provenance. In last part of the manuscript, the stable isotopes of carbon were determined in olive oils by IRMS and allowed to trace the physiological processes of the olive tree to specific environmental characteristics. Each of the three studied single-parameter approaches provided reliable but limited geographic information. Therefore, they were combined together with chemometrics in order to establish an advanced geographical authentication tool able to overcome the most sophisticated fraudulent practices
Briqueu, Louis. "Étude du magmatisme associé aux zones de subduction à l'aide de traceurs géochimiques multiples, éléments traces et rapports isotopiques 87Sr-86Sr-143 Nd-144 Nd /". Montpellier : Centre géologique et géophysique, 1985. http://catalogue.bnf.fr/ark:/12148/cb34863308v.
Texto completoMedini, Salim. "Traçage géographique des huiles d’olive par les isotopes du Sr : développement analytique et application aux huiles AOP de Nîmes". Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4306/document.
Texto completoFor many years, an approach based on the identification of the geographical origin for food product has been implemented through the knowledge of its Sr isotopes, particularly through the analysis of 87Sr / 86Sr ratio. The objective of this thesis is to develop a similar strategy for the olive oils, from the example of PDO Nimes (Gard), in southern France. A specific methodology is necessary since the existing purification protocols of Sr revealed themselves inadequate because of viscosity, high organic load, low Sr content of this matrix In order to proceed to the analysis of the isotopic composition (IC), the first part of the study highlights the definition and validation of a specific method for the treatment of olive oils and strontium purification. The second part of the study is dedicated to expose the processes of assimilation and transfer of strontium into the olive tree. This approach, conducted through a detailed study of one of Nîmes PDO mills, demonstrated that the transfer of strontium from soils to olive tree, and within the olive tree, occurs without isotope fractionation.The last part of the manuscript studies the isotopic ratios 87Sr / 86Sr of the ten PDO olive oils of Nimes and consists in a comparison of this signature with the geological formations underlying the cultivation soils. This approach allows discussing quality of Sr isotopic tool in the geographical recognition of the olive products. The observed similarity between th IC from oils and soil allow us to conclude that, in this context of production, the Sr isotopes are a efficient tool to trace and certify the geographical origin of the oil
Martin, Jean. "Développement de la microchimie élémentaire et isotopique (87Sr : 86Sr) des otolithes de saumons Atlantique : évaluation du potentiel pour un appui à la gestion piscicole dans le bassin de l’Adour". Thesis, Pau, 2013. http://www.theses.fr/2013PAUU3004/document.
Texto completoThe Adour basin holds one of the largest populations of Atlantic salmon in southern Europe exploited by commercial and sport fisheries. Determining the relative contributions of individual rivers and hatcheries to the Adour basin populations becomes crucial to understand key sources that contribute the most to its persistence. We successfully used Sr:Ca, Ba:Ca and 87Sr:86Sr ratios as natural tags for determining the natal origins of adults from 12 tributaries. Success in discriminating between fish from different sites was greatest using Sr isotopes since the latter remained relatively constant across years at a given location. Geochemical signatures from core regions of the otolith were also used to identify fish from hatchery or naturally spawned sources. The predominance of adults spawned in the Ossau River among returning adults corresponded with long-term juvenile production trends in the Ossau River. Despite the limited upstream accessibility of the Pau River, our study demonstrated that Atlantic salmon recruits can successfully leave this river to join the adult population in the Adour basin. We observed relatively clear separation between hatchery and wild juveniles using both Sr:Cacore (wild > 2.5 and hatchery < 0.80) and 87Sr:86Srcore (wild < 0.710 and hatchery > 0.710). The return of hatchery reared fish as adult spawners represented 10% of the total sampled fish we analyzed. Almost all adults, previously identified as belonging to the Ouzom River, were hatchery produced. Adults originated from the Pau River were either wild or hatchery reared fish. We also conducted field controlled experiments that characterized the elemental uptake process in juvenile Atlantic salmon otoliths during freshwater residency. Physiological effects influenced Ba deposition. Ba:Ca otolith profiles from hatchery-reared and field collected fish were characterised by a peak at yolk absorption mark. Hatchery-reared fish stocked in a river also displayed a peak of Ba:Ca following transfer which was not related to the water chemistry. Our experiment revealed a 20-day lag time between initial Ba:Cawater changes and Ba:Caotolith saturation. Results suggested that such effects should be considered during any attempts to determine rivers of origin of Atlantic salmon based on otolith elemental composition or reconstruct the movement of individual fish among and within streams
Drugat, Laurine. "Géochimie des spéléothèmes du sud-ouest de l'Europe (chronologie U-Th et 14C, éléments traces, 87Sr/86Sr, 18O/16O, 13C/12C) appliquée aux reconstitutions climatiques et environnementales à l'Holocène". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLV066.
Texto completoThe purpose of this thesis is to use speleothem geochemistry through a multi-proxy study to reconstruct environmental and climatic variations in southwestern Europe during the Holocene. This work, based on three sites distributed between Spain and France, covers the last 14,000 years. Due to its location at the confluence of the high and low latitudes, this region of south-western Europe is especially sensitive to both the influence of the North Atlantic climate but also the Mediterranean and subtropical African and Asian climate. This particular context allows to study ideally the impact of the different climatic mechanisms driving the modifications of its environment. The choice of the study sites’ distribution aims to compare sites with main Atlantic influence (Candamo, N Spain), Mediterranean (Salamandre cave, SE France) and mixt one (Nerjà, S Spain). The understanding of geochemical behavior was the first part of this study. After the establishment of a chronological frame (14C, U/Th), elemental geochemistry (trace elements and rare earth elements) and isotopic (87Sr/86Sr, d18O, d13C) was coupled. The 87Sr/86Sr isotope ratio, traditionally used as a source tracer for Sr, has been coupled to the study of elementary variations of alkali elements (Li, Rb, Cs) in order to determine changes in the contribution of bedrock and soil in speleothems. The behavior of these alkalis has also been shown to be related to different modes of transport (particulate dissolved or bound to organic complexes) and the use of d13C and rare earths (light rare earth and heavy rare earth fractionation and cerium anomaly) made it possible to confirm or not these hypotheses. The second part of this work was to apply these geochemical mechanisms to the determination of the hydrological and environmental processes and to place them in the specific climatic context of each study site. Thus, the alkali elements (Li, Rb, Cs) have proved to be good indicators of weathering phenomena that may be related to climate change (such as the transition between Bölling-Alleröd and Younger-Dryas in the Salamandre site), and/or environmental changes (period of deforestation or establishment of vegetation in the Middle Holocene in the case of the sites of Nerjà or Candamo). These events can thus take place in very different contexts (dry climate, deforestation, detrital inputs during wet climate by leaching) the coupling to other proxis is then necessary to specify the conditions of enrichment of these alkali elements
Drugat, Laurine. "Géochimie des spéléothèmes du sud-ouest de l'Europe (chronologie U-Th et 14C, éléments traces, 87Sr/86Sr, 18O/16O, 13C/12C) appliquée aux reconstitutions climatiques et environnementales à l'Holocène". Electronic Thesis or Diss., Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLV066.
Texto completoThe purpose of this thesis is to use speleothem geochemistry through a multi-proxy study to reconstruct environmental and climatic variations in southwestern Europe during the Holocene. This work, based on three sites distributed between Spain and France, covers the last 14,000 years. Due to its location at the confluence of the high and low latitudes, this region of south-western Europe is especially sensitive to both the influence of the North Atlantic climate but also the Mediterranean and subtropical African and Asian climate. This particular context allows to study ideally the impact of the different climatic mechanisms driving the modifications of its environment. The choice of the study sites’ distribution aims to compare sites with main Atlantic influence (Candamo, N Spain), Mediterranean (Salamandre cave, SE France) and mixt one (Nerjà, S Spain). The understanding of geochemical behavior was the first part of this study. After the establishment of a chronological frame (14C, U/Th), elemental geochemistry (trace elements and rare earth elements) and isotopic (87Sr/86Sr, d18O, d13C) was coupled. The 87Sr/86Sr isotope ratio, traditionally used as a source tracer for Sr, has been coupled to the study of elementary variations of alkali elements (Li, Rb, Cs) in order to determine changes in the contribution of bedrock and soil in speleothems. The behavior of these alkalis has also been shown to be related to different modes of transport (particulate dissolved or bound to organic complexes) and the use of d13C and rare earths (light rare earth and heavy rare earth fractionation and cerium anomaly) made it possible to confirm or not these hypotheses. The second part of this work was to apply these geochemical mechanisms to the determination of the hydrological and environmental processes and to place them in the specific climatic context of each study site. Thus, the alkali elements (Li, Rb, Cs) have proved to be good indicators of weathering phenomena that may be related to climate change (such as the transition between Bölling-Alleröd and Younger-Dryas in the Salamandre site), and/or environmental changes (period of deforestation or establishment of vegetation in the Middle Holocene in the case of the sites of Nerjà or Candamo). These events can thus take place in very different contexts (dry climate, deforestation, detrital inputs during wet climate by leaching) the coupling to other proxis is then necessary to specify the conditions of enrichment of these alkali elements
Giannesini, Sophie. "Géochimie isotopique couplée des eaux des formations argileuses et calcaires du site Andra de Meuse/Haute-Marne". Phd thesis, Aix-Marseille 3, 2006. http://tel.archives-ouvertes.fr/tel-00204775.
Texto completoLes eaux porales des argilites s'avèrent être d'origine météorique, ce qui signifie que les eaux marines originellement présentes ont été envahies par des eaux météoriques, probablement par diffusion. Les eaux des deux formations calcaires encadrant les argilites présentent des signatures géochimiques distinctes, révélant le rôle d'écran joué par la couche imperméable des argilites.
Khaska, Mahmoud. "Vulnérabilité des ressources en eau souterraine : origines de la salinité en domaine karstique côtier et de la contamination après-mine en métaux lourds. Approche par multitracage géochimique". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4381.
Texto completoThe first theme has for objectives: 1) to trace the origin of the salinity of the waters of the karst aquifers in coastal environment mediterraneen,2) to quantify the mixing proportions between salt waters and the waters karstiques,3) to discriminate the geochemical tracers to identify and model the process of salinization of aquifers coastal karst. The second theme has for objectives:1) to establish the [hast] of natural origin of surface waters and groundwater, 2) to quantify the level of contamination by arsenic in these waters and its spatial and temporal variability 3) to trace the natural or anthropogenic origin of pollution in hast to the aid of isotopic tools adapted. the origins of the salinity identified include i) of came from deep waters salted ii) of come deep water salted dating back toward the surface by a major flaw normal. The 36Cl/Cl has allowed us to identify the origin of deep saline waters and a recharge of meteoric water infiltrated during the period of thermonuclear tests. The PHREEQC modeling used to differentiate between the mixture with a deep water of salt that one with a sea water current. The 87SR/ 86Sr shows a conservative behavior for tracing the origin of saline waters in karst aquifers. The plotters Cs, Rb, Li and B allows to differentiate the three origins identified of salinity. The data acquired on the contamination in hast underline a net increase and perennial of [hast] from the ancient sites of mining processing rehabilitated. The reports 87SR/ 86Sr and δ18O and δ2H will reveal in this case a chartplotter very discriminant of natural or anthropogenic origin of arsenic