The Experts below are selected from a list of 282 Experts worldwide ranked by ideXlab platform
Hélène Pauwels - One of the best experts on this subject based on the ideXlab platform.
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Lead Isotopes in groundwater as an indicator of water rock interaction masheshwaram catchment andhra pradesh india
Chemical Geology, 2010Co-Authors: Philippe Négrel, Catherine Guerrot, Romain Millot, Stephane Roy, Hélène PauwelsAbstract:This study reports on the Lead geochemistry and Pb-isotope ratios of ground waters along a small (53 km(2)) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh). The main focus is on granitic parent rock composition, water chemistry and isotope tracing, through the determination of Lead Isotopes in water by Multi-Collector ICP-MS using an improved new procedure. This method is efficient to give reliable Pb-isotope ratios with uncertainties (i.e. lower than 0.3% on each Pb-206, Pb-207, Pb-208 ratios normalized to Pb-204) low enough to allow the different types of groundwater to be discriminated. Lead concentrations span over one or two orders of magnitude up to approximately 20 mu g L-1. Pb Isotopes fluctuate largely as exemplified by the Pb-206/Pb-204 ratio, ranging from 17.01 up to 25.35. Most of the Lead in the ground waters is of geogenic origin, and through the Lead isotopic signature in groundwater, we have traced and fingerprinted the processes of water-rock interaction considering the granite matrix. Combining a weathering model and field observations, we were able to define a two step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main mineral from the granite in a second step of weathering
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Lead Isotopes in groundwater as an indicator of water–rock interaction (Masheshwaram catchment, Andhra Pradesh, India)
Chemical Geology, 2010Co-Authors: Philippe Négrel, Catherine Guerrot, Romain Millot, Stephane Roy, Hélène PauwelsAbstract:This study reports on the Lead geochemistry and Pb-isotope ratios of ground waters along a small (53 km(2)) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh). The main focus is on granitic parent rock composition, water chemistry and isotope tracing, through the determination of Lead Isotopes in water by Multi-Collector ICP-MS using an improved new procedure. This method is efficient to give reliable Pb-isotope ratios with uncertainties (i.e. lower than 0.3% on each Pb-206, Pb-207, Pb-208 ratios normalized to Pb-204) low enough to allow the different types of groundwater to be discriminated. Lead concentrations span over one or two orders of magnitude up to approximately 20 mu g L-1. Pb Isotopes fluctuate largely as exemplified by the Pb-206/Pb-204 ratio, ranging from 17.01 up to 25.35. Most of the Lead in the ground waters is of geogenic origin, and through the Lead isotopic signature in groundwater, we have traced and fingerprinted the processes of water-rock interaction considering the granite matrix. Combining a weathering model and field observations, we were able to define a two step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main mineral from the granite in a second step of weathering
Philippe Négrel - One of the best experts on this subject based on the ideXlab platform.
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Lead Isotopes tracing weathering and atmospheric deposition in a small volcanic catchment
Comptes Rendus Géoscience, 2015Co-Authors: Philippe Négrel, Emmanuelle Petelet-giraud, Catherine Guerrot, Romain MillotAbstract:Lead Isotopes were studied in soil and sediments of the small volcanic catchment in the Massif Central (France), a large area of Tertiary to Recent continental alkaline volcanism. The comparison of Pb and K (normalized to Zr) shows a linear evolution of weathering processes, whereby Lead enrichment from atmospheric deposition is a major contributor explaining the deviation of several points from this line. A box model simulates the Lead evolution in sediments from soil production on the hillslopes due to bedrock weathering and from anthropogenic input through atmospheric deposition and constrains the dynamics of sediment transfer. Lead isotope ratios decrease from bedrock to sediment and soil without any clear relationship when compared to Lead contents. Pb isotopic compositions showed that most of the Lead budget in sediment and soil results from bedrock weathering with influence of gasoline-additive-Lead and past mining activities derived inputs, but no Lead input from agricultural activity.
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Lead Isotopes in sediments of the Loire River (France): natural versus anthropogenic origin
2012Co-Authors: Philippe Négrel, Emmanuelle Petelet-giraudAbstract:Sediments along the Loire River (central France) were investigated by means of Lead Isotopes determined on the labile sediment fraction, or acid-extractable matter (AEM). The combination of trace elements and Lead Isotopes allows deciphering the origin of the elements (i.e. natural or anthropogenic) and their history, both in the sediment and soil from two small watersheds (one draining basalt, the other one granite-gneiss gneiss in the upper part of the catchment), in present-day suspended matter in Loire River water, and in sediment from the Loire estuary. Fe-Mn oxides act as the main carrier phase of the elements in the AEM extracted by cold HBr, Th and Pb concentrations were determined by ICP-MS and Lead Isotopes by ICP-MS-MC Neptune. Thorium displays mostly insoluble behaviour in hydrosystems, but the small amount of dissolved Th shows a strong tendency to be adsorbed onto oxyhydroxides. Therefore, Mn and Th (as well as other trace elements) correlate well in AEM, the correlations of Mn, and Pb with Th as a typical indicator of crustal weathering points to their derivation from the silicate basement of the upstream part of the catchment. Crustal weathering, as confirmed by the Pb-isotope ratios for most sample points, is the main natural source of Lead in the upstream part of the Loire River, as well as that transported in the middle part of the basin and up to the estuary. Among anthropogenic sources, the use of Pb-isotopic compositions shows an influence of agricultural Lead-derived inputs and a large input from Lead as a gasoline additive, particularly in the estuary due to harbour activities and for one downstream tributary river that is strongly marked by this type of Lead input.
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Lead and Lead Isotopes in agricultural soils of Europe - The continental perspective
Applied Geochemistry, 2012Co-Authors: Clemens Reimann, Philippe Négrel, Belinda Flem, Karl Fabian, Manfred Birke, Anna Ladenberger, Alecos Demetriades, Jurian HoogewerffAbstract:Lead Isotopes are widely used for age dating, for tracking sources of melts, sediments, Pb products, food and animals and for studying atmospheric Pb contamination. For the first time, amap of a Pb isotope landscape at the continental-scale is presented. Agricultural soil samples (A(p)-horizon, 0-20 cm) collected at an average density of 1 site/2500 km(2) were analysed for Pb concentration and Pb Isotopes (Pb-206, Pb-207, Pb-208). Lead concentrations vary from 1.6 to 1309 mg/kg, with a median of 16 mg/kg. Isotopic ratios of Pb-206/Pb-207 range from 1.116 to 1.727 with a median of 1.202. The new data define the soil geochemical Pb background for European agricultural soil, providing crucial information for geological, environmental and forensic sciences, public health, environmental policy and mineral exploration. The European continental-scale patterns of Pb concentrations and Pb Isotopes show a high variability dominated by geology and influenced by climate. Lead concentration anomalies mark most of the known mineralised areas throughout Europe. Some local Pb anomalies have a distinct anthropogenic origin.
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Lead Isotopes in groundwater as an indicator of water rock interaction masheshwaram catchment andhra pradesh india
Chemical Geology, 2010Co-Authors: Philippe Négrel, Catherine Guerrot, Romain Millot, Stephane Roy, Hélène PauwelsAbstract:This study reports on the Lead geochemistry and Pb-isotope ratios of ground waters along a small (53 km(2)) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh). The main focus is on granitic parent rock composition, water chemistry and isotope tracing, through the determination of Lead Isotopes in water by Multi-Collector ICP-MS using an improved new procedure. This method is efficient to give reliable Pb-isotope ratios with uncertainties (i.e. lower than 0.3% on each Pb-206, Pb-207, Pb-208 ratios normalized to Pb-204) low enough to allow the different types of groundwater to be discriminated. Lead concentrations span over one or two orders of magnitude up to approximately 20 mu g L-1. Pb Isotopes fluctuate largely as exemplified by the Pb-206/Pb-204 ratio, ranging from 17.01 up to 25.35. Most of the Lead in the ground waters is of geogenic origin, and through the Lead isotopic signature in groundwater, we have traced and fingerprinted the processes of water-rock interaction considering the granite matrix. Combining a weathering model and field observations, we were able to define a two step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main mineral from the granite in a second step of weathering
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Lead Isotopes in groundwater as an indicator of water–rock interaction (Masheshwaram catchment, Andhra Pradesh, India)
Chemical Geology, 2010Co-Authors: Philippe Négrel, Catherine Guerrot, Romain Millot, Stephane Roy, Hélène PauwelsAbstract:This study reports on the Lead geochemistry and Pb-isotope ratios of ground waters along a small (53 km(2)) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh). The main focus is on granitic parent rock composition, water chemistry and isotope tracing, through the determination of Lead Isotopes in water by Multi-Collector ICP-MS using an improved new procedure. This method is efficient to give reliable Pb-isotope ratios with uncertainties (i.e. lower than 0.3% on each Pb-206, Pb-207, Pb-208 ratios normalized to Pb-204) low enough to allow the different types of groundwater to be discriminated. Lead concentrations span over one or two orders of magnitude up to approximately 20 mu g L-1. Pb Isotopes fluctuate largely as exemplified by the Pb-206/Pb-204 ratio, ranging from 17.01 up to 25.35. Most of the Lead in the ground waters is of geogenic origin, and through the Lead isotopic signature in groundwater, we have traced and fingerprinted the processes of water-rock interaction considering the granite matrix. Combining a weathering model and field observations, we were able to define a two step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main mineral from the granite in a second step of weathering
Catherine Guerrot - One of the best experts on this subject based on the ideXlab platform.
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Lead Isotopes tracing weathering and atmospheric deposition in a small volcanic catchment
Comptes Rendus Géoscience, 2015Co-Authors: Philippe Négrel, Emmanuelle Petelet-giraud, Catherine Guerrot, Romain MillotAbstract:Lead Isotopes were studied in soil and sediments of the small volcanic catchment in the Massif Central (France), a large area of Tertiary to Recent continental alkaline volcanism. The comparison of Pb and K (normalized to Zr) shows a linear evolution of weathering processes, whereby Lead enrichment from atmospheric deposition is a major contributor explaining the deviation of several points from this line. A box model simulates the Lead evolution in sediments from soil production on the hillslopes due to bedrock weathering and from anthropogenic input through atmospheric deposition and constrains the dynamics of sediment transfer. Lead isotope ratios decrease from bedrock to sediment and soil without any clear relationship when compared to Lead contents. Pb isotopic compositions showed that most of the Lead budget in sediment and soil results from bedrock weathering with influence of gasoline-additive-Lead and past mining activities derived inputs, but no Lead input from agricultural activity.
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Lead Isotopes in groundwater as an indicator of water rock interaction masheshwaram catchment andhra pradesh india
Chemical Geology, 2010Co-Authors: Philippe Négrel, Catherine Guerrot, Romain Millot, Stephane Roy, Hélène PauwelsAbstract:This study reports on the Lead geochemistry and Pb-isotope ratios of ground waters along a small (53 km(2)) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh). The main focus is on granitic parent rock composition, water chemistry and isotope tracing, through the determination of Lead Isotopes in water by Multi-Collector ICP-MS using an improved new procedure. This method is efficient to give reliable Pb-isotope ratios with uncertainties (i.e. lower than 0.3% on each Pb-206, Pb-207, Pb-208 ratios normalized to Pb-204) low enough to allow the different types of groundwater to be discriminated. Lead concentrations span over one or two orders of magnitude up to approximately 20 mu g L-1. Pb Isotopes fluctuate largely as exemplified by the Pb-206/Pb-204 ratio, ranging from 17.01 up to 25.35. Most of the Lead in the ground waters is of geogenic origin, and through the Lead isotopic signature in groundwater, we have traced and fingerprinted the processes of water-rock interaction considering the granite matrix. Combining a weathering model and field observations, we were able to define a two step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main mineral from the granite in a second step of weathering
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Lead Isotopes in groundwater as an indicator of water–rock interaction (Masheshwaram catchment, Andhra Pradesh, India)
Chemical Geology, 2010Co-Authors: Philippe Négrel, Catherine Guerrot, Romain Millot, Stephane Roy, Hélène PauwelsAbstract:This study reports on the Lead geochemistry and Pb-isotope ratios of ground waters along a small (53 km(2)) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh). The main focus is on granitic parent rock composition, water chemistry and isotope tracing, through the determination of Lead Isotopes in water by Multi-Collector ICP-MS using an improved new procedure. This method is efficient to give reliable Pb-isotope ratios with uncertainties (i.e. lower than 0.3% on each Pb-206, Pb-207, Pb-208 ratios normalized to Pb-204) low enough to allow the different types of groundwater to be discriminated. Lead concentrations span over one or two orders of magnitude up to approximately 20 mu g L-1. Pb Isotopes fluctuate largely as exemplified by the Pb-206/Pb-204 ratio, ranging from 17.01 up to 25.35. Most of the Lead in the ground waters is of geogenic origin, and through the Lead isotopic signature in groundwater, we have traced and fingerprinted the processes of water-rock interaction considering the granite matrix. Combining a weathering model and field observations, we were able to define a two step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main mineral from the granite in a second step of weathering
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the origin of atmospheric particles in paris a view through carbon and Lead Isotopes
Atmospheric Environment, 2004Co-Authors: David Widory, Stephane Roy, Yvon Le Moullec, Ghislaine Goupil, Alain Cocherie, Catherine GuerrotAbstract:The origin of particulate matter in the urban atmosphere and the impact of its various sources are still subject to debate. This uncertainty cannot be alleviated by the sole use of ‘classic’ chemical parameters, creating a need for complementary indexes. We show that the use of coupled carbon and Lead Isotopes allows the identification of aerosol sources in the atmosphere of Paris, permitting a semi-quantification of their respective contributions. The two study sites, representative of background pollution and the influence of heavy road traffic, both show the domination of diesel exhaust fumes to the level of carbon in aerosols (either PM2.5 or PM10), while industry is the main vector for Lead, with a contribution generally superior to 50%. Within the last 10 years, the origin of the inorganic phase shifted from road traffic towards industrial activities.
Stephane Roy - One of the best experts on this subject based on the ideXlab platform.
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Lead Isotopes in groundwater as an indicator of water rock interaction masheshwaram catchment andhra pradesh india
Chemical Geology, 2010Co-Authors: Philippe Négrel, Catherine Guerrot, Romain Millot, Stephane Roy, Hélène PauwelsAbstract:This study reports on the Lead geochemistry and Pb-isotope ratios of ground waters along a small (53 km(2)) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh). The main focus is on granitic parent rock composition, water chemistry and isotope tracing, through the determination of Lead Isotopes in water by Multi-Collector ICP-MS using an improved new procedure. This method is efficient to give reliable Pb-isotope ratios with uncertainties (i.e. lower than 0.3% on each Pb-206, Pb-207, Pb-208 ratios normalized to Pb-204) low enough to allow the different types of groundwater to be discriminated. Lead concentrations span over one or two orders of magnitude up to approximately 20 mu g L-1. Pb Isotopes fluctuate largely as exemplified by the Pb-206/Pb-204 ratio, ranging from 17.01 up to 25.35. Most of the Lead in the ground waters is of geogenic origin, and through the Lead isotopic signature in groundwater, we have traced and fingerprinted the processes of water-rock interaction considering the granite matrix. Combining a weathering model and field observations, we were able to define a two step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main mineral from the granite in a second step of weathering
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Lead Isotopes in groundwater as an indicator of water–rock interaction (Masheshwaram catchment, Andhra Pradesh, India)
Chemical Geology, 2010Co-Authors: Philippe Négrel, Catherine Guerrot, Romain Millot, Stephane Roy, Hélène PauwelsAbstract:This study reports on the Lead geochemistry and Pb-isotope ratios of ground waters along a small (53 km(2)) endoreic granitic catchment in India (Masheshwaram, Andhra Pradesh). The main focus is on granitic parent rock composition, water chemistry and isotope tracing, through the determination of Lead Isotopes in water by Multi-Collector ICP-MS using an improved new procedure. This method is efficient to give reliable Pb-isotope ratios with uncertainties (i.e. lower than 0.3% on each Pb-206, Pb-207, Pb-208 ratios normalized to Pb-204) low enough to allow the different types of groundwater to be discriminated. Lead concentrations span over one or two orders of magnitude up to approximately 20 mu g L-1. Pb Isotopes fluctuate largely as exemplified by the Pb-206/Pb-204 ratio, ranging from 17.01 up to 25.35. Most of the Lead in the ground waters is of geogenic origin, and through the Lead isotopic signature in groundwater, we have traced and fingerprinted the processes of water-rock interaction considering the granite matrix. Combining a weathering model and field observations, we were able to define a two step weathering process that includes a control on the Pb-isotope ratios by accessory phases and by the main mineral from the granite in a second step of weathering
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the origin of atmospheric particles in paris a view through carbon and Lead Isotopes
Atmospheric Environment, 2004Co-Authors: David Widory, Stephane Roy, Yvon Le Moullec, Ghislaine Goupil, Alain Cocherie, Catherine GuerrotAbstract:The origin of particulate matter in the urban atmosphere and the impact of its various sources are still subject to debate. This uncertainty cannot be alleviated by the sole use of ‘classic’ chemical parameters, creating a need for complementary indexes. We show that the use of coupled carbon and Lead Isotopes allows the identification of aerosol sources in the atmosphere of Paris, permitting a semi-quantification of their respective contributions. The two study sites, representative of background pollution and the influence of heavy road traffic, both show the domination of diesel exhaust fumes to the level of carbon in aerosols (either PM2.5 or PM10), while industry is the main vector for Lead, with a contribution generally superior to 50%. Within the last 10 years, the origin of the inorganic phase shifted from road traffic towards industrial activities.
Thomas F Nagler - One of the best experts on this subject based on the ideXlab platform.
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osmium and Lead Isotopes of rare osirru minerals derivation from the core mantle boundary region
Earth and Planetary Science Letters, 1999Co-Authors: John M Bird, Anders Meibom, Robert Frei, Thomas F NaglerAbstract:We report exceptionally high Os-186/Os-188 for rare crystals of OsIrRu found in unconsolidated sediment near Port Orford, SW Oregon (USA), that are held to be derived from peridotite: in the nearby Klamath Mountains. These OsIrRu samples differ in composition from OsIr alloys thought to have formed in the upper mantle. They have resided in equilibrium with an evolved and highly supra-chondritic Pt/Os reservoir. We explore these data in the context of the core-mantle mixing model relevant to some deep-seated plume systems, and find the investigated alloys to exhibit an apparent coupled Os-186/Os-188 and Os-187/Os-188 (gamma Os(t = 1.4Ga) = +6 to +10) enrichment relative to the chondritic mantle at similar to 1.4 Ga, Our interpretation is that these samples crystallized at similar to 1.4 Ga in a long-term Pt/Os nod Re/Os enriched region, similar to that expected for Earth's outer core or the core-mantle transition zone (D " layer). Subsequently, these OsIrRu samples were transported from the core-mantle boundary region to the lithosphere as xenoliths in a mantle plume/convection system. Lead Isotopes positively exclude a crustal origin of these OsIrRu crystals and support our estimated time of crystallization. (C) 1999 Elsevier Science B.V. All rights reserved.
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osmium and Lead Isotopes of rare osirru minerals derivation from the core mantle boundary region
Earth and Planetary Science Letters, 1999Co-Authors: John M Bird, Anders Meibom, Robert Frei, Thomas F NaglerAbstract:We report exceptionally high Os-186/Os-188 for rare crystals of OsIrRu found in unconsolidated sediment near Port Orford, SW Oregon (USA), that are held to be derived from peridotite: in the nearby Klamath Mountains. These OsIrRu samples differ in composition from OsIr alloys thought to have formed in the upper mantle. They have resided in equilibrium with an evolved and highly supra-chondritic Pt/Os reservoir. We explore these data in the context of the core-mantle mixing model relevant to some deep-seated plume systems, and find the investigated alloys to exhibit an apparent coupled Os-186/Os-188 and Os-187/Os-188 (gamma Os(t = 1.4Ga) = +6 to +10) enrichment relative to the chondritic mantle at similar to 1.4 Ga, Our interpretation is that these samples crystallized at similar to 1.4 Ga in a long-term Pt/Os nod Re/Os enriched region, similar to that expected for Earth's outer core or the core-mantle transition zone (D " layer). Subsequently, these OsIrRu samples were transported from the core-mantle boundary region to the lithosphere as xenoliths in a mantle plume/convection system. Lead Isotopes positively exclude a crustal origin of these OsIrRu crystals and support our estimated time of crystallization. (C) 1999 Elsevier Science B.V. All rights reserved.