Dissertations / Theses on the topic 'S isotopes'
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Salgado, Souto Sergio Adrian, and Souto Sergio Adrian Salgado. "A Re-Os Geochronology and Multi Stable Isotope (C, N, S, Sr, Pb) Systematics of Source Rocks and Crude Oils from the Sonda de Campeche Petroleum System, Mexico." Diss., The University of Arizona, 2018. http://hdl.handle.net/10150/626760.
Full textHerreros, Julien. "Interprétations sur le dernier siècle du profil isotopique de l'eau dans deux carottes de glace andines (Coropuna, Pérou, 15°s et San Valentin, Chili, 46°s)." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20026/document.
Full textThis work is focused on the analyses of two new isotopic records (d18O and dD) from Andean ice cores in the subtropics and temperate latitudes. The first 42 m-long ice core was extracted in 2003 from the saddle of Coropuna glacier in Peru (72°39'W, 15°32'S, 6425 m), and the second 122 m-long core in 2007 from the San Valentin summit in Chile (46°35'S, 73°19'W, 4032 m). The isotopic signals were investigated for their suitability as climate archives over the last century, covering the 42 m-long ice core from Coropuna and the first 70 meters of the core from San Valentin, in two different climatic regions. We observed that the isotopic records are affected by post-depositional processes. At the saddle of Coropuna, isotopic homogenization occurs below 3 m as a result of meltwater percolation and isotopic diffusion, and thus the climatic interpretation is not possible. At the San Valentin summit, removal and/or re-deposition of snow by strong winds occurring throughout the year may create a lack of one or more annual snow layers or, on the other hand, may cause unexpected deposits of several meters. Due to these potential conditions, we cannot always identify the annual isotopic cycles and the isotopes histories show no significant correlation with the climatic parameters because of an uncertain dating
Rouxel, Olivier. "Géochimie isotopique des métaux (Fe, Cu, Sb) et des metalloides (S, Se) dans la croûte océanique." Vandoeuvre-les-Nancy, INPL, 2002. http://www.theses.fr/2002INPLA43N.
Full textYu, Huimin. "Li, Hf and Os Isotope Systematics of Azores Basalts and A New Microwave Digestion Method for Os Isotopic Analysis." Miami University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=miami1322847998.
Full textDogramaci, Shawan Shawket. "Isotopes of sulphur, oxygen, strontium and carbon in groundwater as tracers of mixing and geochemical processes, Murray Basin, Australia /." Title page, table of contents and abstract only, 1998. http://web4.library.adelaide.edu.au/theses/09PH/09phd654.pdf.
Full textAlmeida, J. [Verfasser]. "The capture cross sections of the neon isotopes and the s-process neutron balance / J. Almeida." Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1196023824/34.
Full textAbdallah, Maha. "Etude de l’allocation et de la mobilisation du soufre (S) chez le colza d’hiver (Brassica napus L. ) soumis à une oligotrophisation en S." Caen, 2010. http://www.theses.fr/2010CAEN2069.
Full textOilseed rape (Brassica napus L. ) is supposed to be sensitive to S limitation which negatively affects growth. Nevertheless, as little studies clearly assessed the impact of short or long term mineral S limitation, we analyzed its effects on i) biomass production, ii) N and S uptake by , 15N and 34S labelling iii) relative gene expression of nitrate and sulphate transport systems, iv) N and S remobilization and v) leaf senescence dynamics during vegetative growth. The results showed that under short term S limitation and with sufficient initial S reserves, oilseed rape is able to maintain its growth according to the recycling of endogenous S reserves (mostly as sulphate) from old leaves while in the meantime, gene expression encoding sulphate tonoplastic transporters were up-regulated. S fluxes from uptake and S remobilization from leaves were mostly allocated to the roots. Only with both low initial S reserves and low mineral S availability (i. E. Long term S limitation), plant growth was reduced while one of the nitrate transporter gene expressions was steadily down-regulated and root nitrate uptake was also reduced. Moreover, leaf soluble proteins contents, total S, S recently taken up as 34S and sulphate contents in oldest leaves declined despite an up-regulation of the expression of genes encoding plasmalemmic or tonoplastic sulphate transporters. Compared to control plants, S limitation also delayed leaf senescence evaluated by molecular indicators and leaf protein degradation. Overall results demonstrated that the effect of S limitation should be estimated by taking into account plant initial S status, and particularly the sulphate content within the oldest leaves. Our results gave new perspectives for the improvement of Sulphur Use Efficiency and Nitrogen Use Efficiency, because of the tigh inter-connection between theses two metabolisms
Nabbefeld, Birgit. "Biomarker distributions and stable isotopes (C, S, H) to establish palaeoenvironmental change related to the end-Permian mass extinction event." Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/493.
Full textSalesse, Kevin. "Archéo-biogéochimie isotopique, reconstitutions des régimes alimentaires et des schémas de mobilité, et interactions bioculturelles. Les sépultures plurielles de la catacombe des Saints Pierre-et-Marcellin (Rome, Ier-IIIe s. ap. J.-C.) : Les sépultures plurielles de la région X de la catacombe des Saints Pierre-et-Marcellin (Rome, Ier-IIIe s. ap. J.-C.)." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0412/document.
Full textAn assembly of unpublished complex plural burials (1st-3rd cent. AD.) was discovered and partially excavated, between 2003 and 2010 in the central region called X of the catacomb of Saints Peter and Marcellinus in Rome. It contains several hundred individuals which were buried according to uncommon funeral practices following a mortality episode of likely epidemic nature. To understand the life history (diet and mobility patterns) of these deceased and to discuss again certain assumptions previously established on the basis of new evidences, we have as part of this work conducted an archaeo-biogeochemical multi-proxy (14C, δ13C, δ15N, δ18O et 87Sr/86Sr) and multi-tissue (enamel, bones, hair) approach on a sub-sample of 130 individuals coming from six different chambers. At the outset, we tested the biochemical and isotopic integrity of mineral (carbonate phases) and organic fractions (collagen and keratin phases) samples from conventional indicators measured in routine (%Col, %C, %N, C/N, PCO2 et PCO2/Mass), by FTIR spectroscopy (IRSF, CO3/PO4 and AmideI/PO4) and by an innovative approach consisting of 14C dating on collagen-apatite to validate the isotopic signal of mineral fractions. Our results highlight extreme differences of preservation of all phases. Diagenetic trajectory of samples is however not random but dependent on environmental and taphonomical conditions which differ between small and large chambers. Furthermore, we have been able to demonstrate that, despite strong recrystallization and isotopic exchanges with the sepulchral environment, carbonated phases have an unaltered biogenic isotopic signal. Secondly, we rebuilt the diets of individuals based on robust comparisons repositories and various interpretative models (mono-proxy versus multi-proxies; qualitative versus quantitative) which were, in some cases, adapted to the needs of our study. In general, our results show that most of the individuals had access to such a type diet based on the triad Cereals C3/Meat C3/Marine fish. This type diet would however not be exclusive, some individuals (n = 13) would have indeed occasionally consumed other resources such as freshwater fish or C4 cereals. Our results indicate that changes of diet during the life history are relatively limited. Besides, with regard to consumed food, this population is distinguished from other contemporary Roman populations for whom isotopic values are published. In the third place, we studied individual’s mobility patterns based on a rigorous approach to our data and on a comparison of the most comprehensive repositories as possible with taking into account the bias usually evaded (cultural facts, influence of climate and errors associated with conversion equations). Our results highlight that a minimum of 23% (n = 30) of the studied individuals are migrants. These, however, are not distinguished from Roman residents through their diet. We were able to show further that these migrants had complex and heterogeneous trajectories during their life within three distinct mobility patterns characterizing them. In terms of migrant’s rates, our population does not differ from other Roman populations for which the isotopic data are available. It differs however by its cosmopolitanism with origins for more diverse migrants: Europe, Africa, Arabia and Asia Minor [...]
Tra il 2003 e il 2010, nella regione centrale chiamata X della catacomba dei Santi Pietro e Marcellino a Roma, è stato scoperto e parzialmente scavato un insieme di sepolture plurime inedite (I-III sec. D.C.) contenente diverse centinaia di individui, i quali sono stati inumati secondo le pratiche funerarie singolari in seguito ad un episodio di sovramortalità di natura probabilmente epidemica. Per comprendere la storia di vita (alimentazione e mobilità) di questi defunti e ridiscutere, sulla base di nuovi elementi, alcune ipotesi precedentemente formulate, abbiamo condotto, nel quadro di questo lavoro, un approccio archeo-biogeochimico multi-proxys (14C, δ13C, δ15N, δ18O e 87Sr/86Sr) e multi-tessuto (smalto, ossa, capelli) su un campione di 130 individui da sei stanze diverse. Abbiamo inizialmente verificato l'integrità biochimica e isotopica delle frazioni minerali (fasi carbonatiche) ed organiche (fasi collageniche e cheratiniche) dei campioni provenienti da indicatori classici misurati in routine (%Col, %C, %N, C/N, PCO2 e PCO2/Massa) e per spettroscopia FTIR (IRSF, CO3/PO4 e AmmideI/PO4) ed un approccio innovativo costituito da datazione 14C su coppie collagene-apatite per validare il segnale isotopico delle frazioni minerali. I nostri risultati mettono in evidenza delle differenze estreme di preservazione di tutte le fasi. La traiettoria diagenetica dei campioni non è però aleatoria, ma dipendente dalle condizioni ambientali e tafonomiche che differiscono tra camere piccole e grandi. Inoltre, abbiamo potuto dimostrare che nonostante delle forti ricristallizzazioni e degli scambi isotopici con l'ambiente sepolcrale, le fasi carbonatiche hanno un segnale isotopico biogenetico inalterato. Abbiamo in un secondo tempo ricostruito i regimi alimentari degli individui basandoci su riferimenti di confronto robusti e vari modelli interpretativi (mono-proxys versus multi-proxys, qualitativi versus quantitativi), i quali sono stati in alcuni casi, adattati alle esigenze del nostro studio. In generale, i nostri risultati mostrano che la maggior parte degli individui ha avuto accesso ad un regime alimentare tipo basato sulla triade Cereali C3/Carne C3/Pesci marini. Questo regime alimentare non è tuttavia esclusivo, avendo certi individui (n = 13) consumato casualmente altre categorie di risorse come il pesce dulciacquicolo o dei cereali C4. I nostri risultati indicano che i cambiamenti di alimentazione nel corso della vita sono relativamente limitati. Inoltre, questa popolazione si distingue da un piano strettamente alimentare rispetto alle altre popolazioni contemporanee romane per le quali dei valori isotopici sono pubblicati. Abbiamo in un terzo tempo studiato gli schemi di mobilità degli individui basandoci su un approccio rigoroso dei nostri dati e su riferimenti di confronto i più esaustivi possibile, e anche tenendo conto di punti di vista solitamente elusi (fatti culturali, influenza del clima e errori associati alle equazioni di conversione). I nostri risultati mettono in luce che a minima 23% (n = 30) degli individui studiati sono migranti. Questi ultimi, tuttavia, non si distinguono per la loro alimentazione dai residenti romani. Abbiamo potuto mostrare, inoltre, che questi migranti hanno avuto percorsi di vita complessi ed eterogenei e che tre schemi di mobilità distinti li caratterizzano. Nostra popolazione non si differenzia in termini di tasso di migranti da altre popolazioni romane per le quali sono disponibili dei dati isotopici. Essa si distingue tuttavia per il suo cosmopolitismo con delle origini per i migranti delle più diverse: Europa, Africa, Arabia e Asia Minore [...]
Gómez, Vallejo Vanessa. "Development of new strategies for the synthesis of radiotracers labeled with short-lived isotopes: application to 11C and 13N." Doctoral thesis, Universitat Ramon Llull, 2010. http://hdl.handle.net/10803/9301.
Full textEn quant al marcatge amb nitrogen-13, s'ha desenvolupat un procés totalment automàtic per a la producció de [13N]NO2- a partir de [13N]NO3- generat en el ciclotró. El precursor radioactiu [13N]NO2- s'ha utilitzat per la radiosíntesi de compostos amb interès biològic com ara S-nitrosotiols (donadors de NO.), N-nitrosamines (molècules amb potencials efectes carcinogènics) i azo compostos (amb possible aplicació com a radiotraçadors per a la detecció in vivo de plaques de β-amiloide). En tots els casos es van obtenir excel·lents conversions radioquímiques (48.7% - 74.5% per S-[13N]nitrosotiols, 45.6% - 53.4% per N-[13N]nitrosamines i 40.0% - 58.3% per 13N-azo compostos) i bons rendiments radioquímics (33.8% - 60.6% per S-[13N]nitrosotiols, 34.0% - 37.8% per N-[13N]nitrosamines i 20.4% - 47.2% per 13N-azo compostos). A més a més, s'ha dissenyat i implementat un mòdul automàtic amb control remot pel marcatge de molècules amb 13N.
Se ha desarrollado una nueva estrategia para la síntesis rápida y eficiente de L-[metil-11C]metionina basada en el captive solvent method. La reacción de L-homocisteína (disolución básica en agua/etanol 1:1) con [11C]CH3I en un loop de HPLC permitió la formación del radiotrazador deseado con elevado rendimiento radioquímico (38.4 ± 4.1%) en un tiempo corto (< 12 min). Todos los parámetros analíticos cumplían las especificaciones requeridas por la versión actual de la Farmacopea Española, aunque los valores de actividad específica obtenidos fueron relativamente bajos. Por ello, se estudiaron y cuantificaron las principales fuentes que contribuyen a la contaminación de carbono-12 durante las síntesis de [11C]CH3I efectuadas según el "wet" method. Se observó que la principal fuente de contaminación de CO2 no radiactivo (contribución>90%) es el propio proceso de bombardeo, probablemente debido a la combustión (causada por las altas temperaturas y presiones alcanzadas durante la irradiación) de los compuestos que contienen carbono y que se encuentran presentes en el gas irradiado (o en el mismo cuerpo del blanco). Se establecieron procedimientos generales para realizar antes, durante y con posterioridad a la radiosíntesis para prevenir la contaminación exterior y, de esta manera, aumentar la actividad específica de los radiotrazadores sintetizados.
Respecto al marcaje con nitrógeno-13, se ha desarrollado un proceso totalmente automático para la producción de [13N]NO2- a partir del [13N]NO3- generado en el ciclotrón. El precursor radiactivo [13N]NO2- se ha utilizado para la radiosíntesis de compuestos con interés biológico tales como S-nitrosotioles (donadores de NO.), N-nitrosaminas (moléculas con potenciales efectos carcinogénicos) y azo compuestos (con posible aplicación como radiotrazadores para la detección in vivo de placas de β-amiloide). En todos los casos se obtuvieron excelentes conversiones radioquímicas (48.7% - 74.5% para S-[13N]nitrosotioles, 45.6% - 53.4% para N-[13N]nitrosaminas y 40.0% - 58.3% para 13N-azo compuestos) y buenos rendimientos radioquímicos (33.8% - 60.6% para S-[13N]nitrosotioles, 34.0% - 37.8% para N-[13N]nitrosaminas y 20.4% - 47.2% para 13N-azo compuestos). Además, se ha diseñado e implementado un módulo automático con control remoto para el marcaje de moléculas con 13N.
A new strategy for the fast and efficient synthesis of L-[methyl-11C]methionine based on the captive solvent method has been developed. The in loop reaction of a basic water/ethanol 1:1 solution of L-homocysteine with [11C]CH3I led to the formation of the desired radiotracer with high radiochemical yield (38.4 ± 4.1%) in short production time (< 12 min). All analytical parameters were within the specifications of the current version of the Spanish Pharmacopoeia, although specific radioactivity values were relatively low. Thus, the main sources of carbon-12 during the synthesis of [11C]CH3I by the "wet" method were studied and the contribution attributable to each individual source was quantified. The most relevant contamination of non-radioactive CO2 (contribution>90%) was shown to be generated during the bombardment process, probably due to the combustion (caused by high temperature and pressure during irradiation) of carbon carrier compounds present in the irradiated gas (or target body). General procedures to be performed before, during and after the radiosynthesis were established to prevent external contamination and to improve the specific radioactivity of 11C-labeled radiotracers synthesized from [11C]CH3I produced via the "wet" method.
Concerning 13N-labeling, a fully automatic process for the production of [13N]NO2- from cyclotron generated [13N]NO3- has been developed. The radioactive precursor [13N]NO2- has been used for the synthesis of biologically interesting 13N-labeled compounds such as S-nitrosothiols (well-known NO. donors), N-nitrosamines (molecules with potent carcinogenic effects) and azo compounds (with putative application as imaging probes for in vivo detection of β-amyloid plaques). In all cases, excellent radiochemical conversion (48.7% - 74.5% for S-[13N]nitrosothiols, 45.6% - 53.4% for N-[13N]nitrosamines and 40.0% - 58.3% for 13N-labeled azo compounds) and good radiochemical yields (33.8% - 60.6% for S-[13N]nitrosothiols, 34.0% - 37.8% for N-[13N]nitrosamines and 20.4% - 47.2% for 13N-labeled azo compounds) were achieved. An automatic remote controlled synthesis module for the preparation of 13N-labeled structures has been designed and implemented.
Shelton, Jenna Lynn. "Fate(s) of Injected CO₂ in a Coal-Bearing Formation, Louisiana, Gulf Coast Basin: Chemical and Isotopic Tracers of Microbial-Brine-Rock-CO₂ Interactions." Thesis, The University of Arizona, 2013. http://hdl.handle.net/10150/297060.
Full textLomant, Susannah E. "Calculations of nuclear cross sections and astrophysical S-factors for reactions induced by protons and alpha particles on isotopes of copper." Virtual Press, 1999. http://liblink.bsu.edu/uhtbin/catkey/1137475.
Full textDepartment of Physics and Astronomy
Salesse, Kevin. "Archéo-biogéochimie isotopique, reconstitutions des régimes alimentaires et des schémas de mobilité, et interactions bio-culturelles. Les sépultures plurielles de la région X de la catacombe des Saints Pierre-et-Marcellin (Rome, Ier-IIIe s. ap. J.-C.)." Doctoral thesis, Université de Bordeaux, Talence, 2015. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/282723.
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Desbois, Guillaume. "Modélisation 3D de la diffusion atomique dans les minéraux : applications à l'étude des isotopes de l'hydrogène et de l'oxygène, et du couple Al-S." Toulouse 3, 2006. http://www.theses.fr/2006TOU30116.
Full textThis thesis presents a 3D numerical modelling (finite differences) which can simulate atomic diffusion in single crystals. This new tool allows : to simulate anisotropic diffusion, a large choice of cristal shapes, any initial distribution of concentration, any concentration at surface as a function of time and any temperature change as a function of time. The 3D modelling has been applied to four cases of study : three of them deal with experimental hydrogen diffusion in diopside, lawsonite and tourmaline, the fourth deals with Al-Si and O natural diffusion profiles in diopsides from Adirondacks. These studies illustrate the power of the 3D modelling developped for the description and the interpretation of diffusion profiles. This new tool will be very useful for the interpretation of detailed zonations at grain scale measured by modern analytical techniques
Nakwafila, Albertina Nuusiku. "Salinisation source(s) and mechanism(s) in shallow alluvial aquifers along the Buffels River, Northern Cape Province, South Africa." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96826.
Full textENGLISH ABSTRACT: Several areas in Namaqualand are affected by elevated levels of salinity; including the shallow alluvial aquifers along the Buffels River catchment. The chemistry of rainwater that recharges these aquifers has low salt-loads, but the groundwater system is very saline. The shallow alluvial aquifers are an important source of water for several communal areas along the river both for domestic and agricultural purposes. Groundwater is also used for the copper and diamond mining activities along the river. Prior to this study, the sources of salinity to the alluvial aquifers and whether salinity can be remediated has not been determined. Possible salinity sources included seawater intrusion, evaporitic salts dissolution, concentrations by evaporation, deep aquifer brines, dissolution of minerals from the aquifer geology as well as salts from anthropogenic activities (i.e. mining). The source(s) of salinity to the groundwater has been determined using the geochemical as well as the isotopic tracers. The ratios of major ions (i.e. Na/Cl) as well the oxygen (18O), hydrogen (2H), 36Cl/Cl, and 87Sr/86Sr isotopes were used in determining the possible solute sources. In addition to these, the chloride mass balance (CMB) method was used to determine the recharge rates to the alluvial aquifers. Furthermore, the groundwater age of the alluvial aquifers was determined using the tritium (3H) isotope. The groundwater samples have high 87Sr/86Sr ratios, which are in the same ranges as the 87Sr/86Sr ratios in the surrounding granitic rocks indicating water-rock interactions. The 36Cl/Cl ratios are low and indicate the dissolution of old salts. The 18O and 2H stable isotopes of groundwater show an evaporative trend with respect to the LMWL, which indicate that groundwater has been evaporated before or during infiltration. Salinity to the shallow alluvial aquifers was found to be mainly derived from the dissolution of rock mass and concentration by evaporation process. The groundwater is relatively young, but there is mixing between old water recharged prior to bomb testing and recently recharged groundwater in some boreholes. The Chloride mass balance (CMB) method assumes atmospheric chloride is the only source of chloride to the aquifers. However, there is additional chloride to these alluvial aquifers from rock mass dissolution. The estimated recharge rates by CMB method (0.1-3.4mm/a) are therefore underestimated. A simulation model was used to determine the recharge rates based on the annual precipitation that will yield the current measured chloride concentrations in the groundwater. Recharge was found to range from 1-5% of the annual precipitation, which is also low. The CMB method therefore gives significant recharge rate estimates, but they are not accurate and need to be supported by another method.
AFRIKAANSE OPSOMMING: Geen opsomming beskikbaar.
Force, Carole. "Etude de la structure du $^{44}$S par sa décroissance isomérique." Phd thesis, Université de Caen, 2009. http://tel.archives-ouvertes.fr/tel-00430125.
Full textKrammer, Regina. "Calcareous nannofossils in the S-Atlantic during the middle to late Miocene Coccolithophorid carbonate budgets, fine-fraction stable isotopes and their paleoceanographic implications /." [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=979757770.
Full textBrenot, Agnès. "Origine de l'eau et des éléments dissous par traçage isotopique (H, O, S, Mg, Sr) sur le bassin amont de la Moselle." Vandoeuvre-les-Nancy, INPL, 2006. http://docnum.univ-lorraine.fr/public/INPL/2006_BRENOT_A.pdf.
Full textThe objective of this work was to identify and quantify, in time and space, the origin of water and of dissolved elements on the Moselle river basin, using three types of isotopic tracers. This basin is remarkable for its very contrasted lithology and land use at a small distance scale. A strong contrast appears between the Vosges mountains with silicate rocks and mainly forested soils upstream and the Lorraine plateau with carbonate/evaporite rocks and dominated by agriculture downstream. The first objective of this work was to assess some hydrological processes occurring on the basin. The isotopic composition of H and O of water permited to describe water dynamics and reponse delay of water to meteoric events depending on the water reservoir studied and the sampling period. Response delay estimated vary from few days for soil water collected by drains during high flow period, to several weeks for river water, to several months for soil water collected by porous cups and spring water. Secondly, we documented variations of the isotopic composition of S and O of dissolved sulfates in time and space. Three main sources have been identified: atmospheric inputs, weathering of evaporites and leaching of S-fertilizers. Sulfates inputs from S-fertilizers showed a clear seasonality and appeared during high river flow period (October 2003 to March 20004), when the leaching of soils is intensive and would represent up to 13% of the sulfates exported each year by the Madon river at Mirecourt. The isotopic composition of dissolved Sr in rivers on the Moselle basin correspond to a simple mixing between the silicate end-member and the carbonate end-member defined locally, suggesting a relative simplicity of the system studied. On this basis, we tested the potential of Mg as a new isotopic tracer in river systems. Mg in river waters draining silicates is systematically depleted in 26Mg (δ26Mg=-1. 2 and -0. 7‰) relative to corresponding rocks and soils (δ26Mg=0. 2 and 1. 7‰), suggesting that isotope fractionation occurred during weathering. δ26Mg values of dissolved Mg in rivers flowing on sedimentary rocks (-1. 6 to -1. 1‰) are significantly lower than those for rivers flowing on silicate rocks. In addition, δ26Mg values are clearly correlate with 87Sr/86Sr ratio and Sr/Mg ratio, showing that Mg isotopes are able to trace the origin of dissolved Mg for these rivers. Finally, an important excess of Mg and Sr relative to Ca appeared in rivers draining sedimentary rocks on the Lorraine plateau and we demonstrated that the removal of Ca by calcite precipitation is the most likely process to explain this excess
CAVERO, MANCHADO VICTORIA. "La collision reactive li(3#s)+h#2lih+h. Transfert de structure fine 2p#3#/#2-2p#1#/#2 entre isotopes du lithium dans un jet unique." Paris 11, 1997. http://www.theses.fr/1997PA112258.
Full textBjörkvald, Louise. "Landscape hydrogeochemistry of Fe, Mn, S and trace elements (As, Co, Pb) in a boreal stream network." Doctoral thesis, Stockholm University, Department of Geology and Geochemistry, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-8130.
Full textThe transport of elements by streams from headwater regions to the sea is influenced by landscape characteristics. This thesis focuses on the influence of landscape characteristics (e.g. proportion of wetland/forest coverage) on temporal and spatial variations of Fe, Mn, S and trace elements (As, Co, Pb) in streams located in northern Sweden, a boreal region characterized by coniferous forests and peat wetlands.
Water samples from a network of 15 streams revealed a different hydrogeochemistry in forested catchments compared to wetland catchments. The temporal variation was dominated by spring flood, when concentrations of Fe, Mn and trace elements increased in forested headwaters. However, in streams of wetland catchments concentrations decreased, but Pb concentrations were higher in comparison to other streams. Both Fe and Pb showed positive correlations with wetland area, while Co correlated with forest coverage. The anthropogenic contribution of As and Pb appear to be larger than the supply from natural sources.
During spring flood SO42- decreased in most streams, although concentrations increased in streams of wetland catchments. Concentrations of SO42- were higher in streams of forested catchments than in wetland dominated streams, the former being net exporters of S and the latter net accumulators. Isotope values of stream water SO42- (δ34SSO4) were close to that of precipitation during spring flood, indicating that the major source of S is from deposition. The results show that, although emissions of anthropogenic S have been reduced, there is still a strong influence of past and current S deposition on runoff in this region.
In conclusion, wetlands are key areas for the hydrogeochemistry in this boreal landscape. The findings emphasize the importance of understanding stream water chemistry and element cycling from a landscape perspective. This may be important for predicting how boreal regions respond to environmental disturbances such as climate change.
Dubousset, Lucie. "Effet d'une restriction en sulfate couplée ou non à une limitation en nitrate sur l'efficience de mobilisation du S et du N foliaire chez le colza d'hiver (Brassica napus L. ) : Thèse soutenue sur un ensemble de travaux." Caen, 2009. http://www.theses.fr/2009CAEN2074.
Full textThe survey of the physiological and agronomic impacts of a mineral sulphur (S) limitation in oilseed rape (Brassica napus L. ) – an oleagenous very demanding in S but characterized by a weak S use efficiency (SUE) – is of particular interest in the current context of S impoverishment in soils associated with the decrease of atmospheric deposits. Thus, the goals were targeted to (1) determine the stages of development the most sensitive to the S limitation, (2) identify the processes of S and N mobilization/allocation (via 15N/34S labellings) and (3) evaluate the effects of the N availability on these processes. An allometric relationship similar to N with shoot biomass could not be established for S. Whatever the availability in N, a sequestration of sulphate in leaves of plants well supplied with S was revealed in greenhouse and in field experiments. In case of S limitation, the sulfate stored in leaves would be efficiently remobilized towards growing tissues via the induction of tonoplastic transporters (BnSultr4;1 and BnSultr4;2) involved in its efflux. A S restriction at the stage C2 (bolting) affects the N use efficiency. The grain filling and the oil quality depend on the S availability between C2 and D2 (visible buds). Overall results show that the weak SUE in oilseed rape is related to a weak mobilization of sulphate in leaves and that an adapted S fertilization covering the requirements until the beginning of flowering would allow improving the SUE while maintaining seed yield and quality
Andrade, Poliana Carvalho de. "Variações de paleoprodutividade na plataforma continental interna ao largo de Itajaí-SC (26º59'16.8\"S - 048º04'33.6\"W) durante o Holoceno: uma abordagem de multi-indicadores." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/21/21133/tde-27072011-110113/.
Full textMicrofaunal, sedimentological and geochemical analyses from a core collected on the inner shelf off Itajaí, SC, allowed us to recognized , in the last 7,600 years, three phases with different organic matter fluxes and hydrodynamic conditions. The rst phase (7,600 5,000 years cal. B.P.) is characterized by low productivity, evidenced by low values of productivity proxies (organic carbon (Corg), calcium carbonate (CaCO3) and Benthic Foraminífera High Productivity index - BFHP), more intense hydrodynamic regime (dominance of coarser sediments and higher frequencies of Globocassidulina subglobosa) and waters with more oxygen availability (higher values of the Benthic Foraminífera Oxic Index BFOI and relatively high percentages of epifaunal species). The climate during this period was relatively dry and sea-level was approximately 3 m above the present. The second phase (5,000 3,000 years cal. B.P.) is marked by a relative increase in productivity (increase of Corg, CaCO3 and BFHP), hydrodynamical conditions were probably less intense (lower frequencies of G. subglobosa and muddy sediments), and oxygen availability decreased (lower BFOI index values). The climate apparently became progressively more humid and a progressive decline of the sea-level occurred. The third phase (3,000 900 years cal. B.P.) is characterized by a significant increase of productivity (higher percentages of Corg, CaCO3, infaunal and detritivores species, and increase of BFHP index values), probably bottom currents were less intense (muddy sediments and lower frequencies of G. subglobosa) and oxygen contents more restrictive (lower BFOI values). A significant increase in the input of continental material occurs during this period, as highlighted by an increase of Buliminella elegantissima frequencies and increase of the Fe/Ca and Ti/Ca ratios. The increase of productivity could be related to moisture increase throughout the Holocene, due to the intensification of the South American Monsoon system (SAMS) caused by variations in the precession cycle and possibly increased El Niño frequency, which corroborates the increase in rainfall in southern Brazil. The wetter climate and strengthening cold front may have favored the penetration of cold water rich in nutrients from the south, related to the discharge of the Rio de La Plata
Marzouk, Ezzat Rashad El-Said. "Using multi-element stable isotope dilution to quantify metal reactivity in soil." Thesis, University of Nottingham, 2012. http://eprints.nottingham.ac.uk/28914/.
Full textTouzeau, Alexandra. "L'Egypte ancienne, une civilisation face à un changement climatique : le message isotopique (C, N, O, S) des tissus vivants momifiés." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10104.
Full textEgypt is an arid territory, which essentially depends on the Nile river for the irrigation of its agricultural lands. The temporal variability of the river flood thus may have affected directly the dynamics of the Egyptian population. Here, this hypothesis is tested by studying the variation of the climate during Ancient Egypt concurrently to indicators of the life habits of the Egyptians. The variation with time of the δ18Ow of the Nile water is reconstructed from the δ18Op of the apatite phosphate of Egyptian mummies. The increase of +3 ‰ in the Nile water δ18Ow between the predynastic period (5500BP) and the Greco-Roman Period (2000BP) is caused by a change in the conditions of precipitation above the Nile sources. This increase can be the result of an increase in temperature of about +2 °C or of a decrease in the monthly amount of precipitation of about 140 mm. Here, the hypothesis of aridification is preferred: in effect, δ18Op measures on Nile fishes permit to infer a Nile water temperature at the Greco-Roman Period similar to the present-day one. The climatic change seems to have had little impact on the Egyptian civilization. In effect the Egyptian population increases considerably during the selected period and its diet remains funded on C3- plants, feebly adapted to arid environments, with a rare consumption of fishes or other animal protein. The decrease of the flood was admittedly compensated by the technological advances of the Egyptian civilization (shaduf, drainage) which allowed the cultivation of newly reclaimed lands
Seder, Colomina Marina. "Sphaerotilus natans, a neutrophilic iron-related filamentous bacterium : mechanisms of uranium scavenging." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1070/document.
Full textHeavy metals and radionuclides are present in some ecosystems worldwide due to natural contaminations or anthropogenic activities. The use of microorganisms to restore those polluted ecosystems, a process known as bioremediation, is of increasing interest, especially under near-neutral pH conditions. Iron minerals encrusting neutrophilic iron-related bacteria, especially Bacteriogenic Iron Oxides (BIOS), have a poorly crystalline structure, which in addition to their large surface area and reactivity make them excellent scavengers for inorganic pollutants. In this PhD work we studied the different mechanisms of uranium scavenging by the neutrophilic bacterium Sphaerotilus natans, chosen as a model bacterium for iron-related sheath-forming filamentous microorganisms. S. natans can grow as single cells and filaments. The latter were used to investigate U(VI) biosorption and U(VI) sorption onto BIOS. In addition, uranium sorption onto the abiotic analogues of such iron minerals was assessed. In order to use S. natans filaments for U(VI) scavenging, it was necessary to identify factors inducing S. natans filamentation. The influence of oxygen was ascertained by using molecular biology techniques and our results revealed that while saturated oxygen conditions resulted in single cell growth, a moderate oxygen depletion to ~ 3 mg O2.L-1 led to the desired filamentous growth of S. natans. BIOS attached to S. natans filaments as well as the abiotic analogues were analysed by XAS at Fe K-edge. Both materials were identified as amorphous iron(III) phosphates with a small component of Fe(II), with a high reactivity towards scavenging of inorganic pollutants. In addition, EXAFS at the U LIII-edge revealed a common structure for the O shells, while those for P, Fe and C were different for each sorbent. An integrated approach combining experimental techniques and speciation calculations made it possible to describe U(VI) adsorption isotherms by using a surface complexation model. These results suggested the role of phosphoryl and carboxyl groups as the main functional groups involved in the U(VI) biosorption by S. natans. The results of this PhD work will help to better understand the processes governing U(VI) immobilization, either by S. natans biosorption, sorption onto BIOS or sorption onto iron phosphates, an thus the fate of uranium in near-neutral pH environments
Enders, Joachim. "Anregung von Dipol- und Quadrupolmoden in den stabilen Blei-Isotopen mit Photonenstreuung am S-DALINAC und die Kollektivität und Feinstruktur der Scissors Mode." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=960411801.
Full textCharef, Abdelkrim. "La Nature et le rôle des phases fluides associées à la minéralisation Pb-Zn dans les formations carbonatées et leurs conséquences métallogéniques études des inclusions fluides et des isotopes (H,C,O,S,Pb) des gisements des Malines (France), Jbel Hallouf-Sidi Bou Aouane et Fedj-el-Adoum (Tunisie)." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37596635t.
Full textBouchez, Camille. "Bilan et dynamique des intéractions rivières-lac(s)-aquifères dans le bassin hydrologique du lac Tchad : approche couplée géochimie et modélisation des transferts." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4332/document.
Full textLake Chad Basin (LCB) is a 2.5 billion km2 closed drainage basin, in the center of Africa. Lake Chad enhances the climatic variations over the LCB while the multi-layers aquifer system contains large water resources. The hydro(geo)logical response of the LCB to climatic variability is studied by combining geochemical and modeling approaches. The lake Chad levels modeling, calibrated from hydrological, chemical and isotopic data, allows to disentangle evaporation from transpiration and from infiltration. Transpiration, neglected in previous studies, accounts for 15% of the total ET. From the chlorine dynamic in the LCB, a transit time of 10 yr in the upper basin, a short renewal rate of lake waters and their infiltration toward the aquifer are estimated. GCM paleoclimatic simulations over the last millennium were introduced into a rainfall-runoff model (GR2M) and the lake level model. It shows the difficulty to reconcile lake level records from paleohydrological modeling. The detection of thermonuclear 36Cl together with stable isotopic composition of groundwaters allow to draw the present-day recharge distribution in the Quaternary aquifer. Present-day recharge occurs close to surface waters in 60% of the groundwater sampled and an evaporation between 85 and 98% of waters in the surrounding of Lake Chad is estimated. Groundwaters with a contrasted geochemical signature are stored in the center of the piezometric depressions, suggesting no present-day recharge. The deep waters of the CT, with water ages of 300 000 yr, show geochemical patterns indicative of an old and humid recharge period. These original data give new insights into paleorecharge in the Sahelian band
Gromov, Sergey S. [Verfasser]. "Stable isotope composition of atmospheric carbon monoxide : a modelling study / Sergey S. Gromov." Mainz : Universitätsbibliothek Mainz, 2014. http://d-nb.info/1051305497/34.
Full textKarlsson, Cecilia. "Smooth area preserving isotopies of self transverse immersions of S¹ into R²." Thesis, Uppsala universitet, Matematiska institutionen, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-112522.
Full textTang, Xiaohui [Verfasser], and S. [Akademischer Betreuer] Norra. "Separating arsenic oxyanions from natural waters for oxygen isotope analysis / Xiaohui Tang. Betreuer: Dr. S. Norra." Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1047839784/34.
Full textAttisano, Karina Kammer. "Aporte subterrâneo: uma fonte complementar de nutrientes para a costa do Sul do Brasil e plataforma adjacente." reponame:Repositório Institucional da FURG, 2012. http://repositorio.furg.br/handle/1/4263.
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A alta produtividade na zona costeira e na Plataforma Continental do Sul do Brasil é dada pelo aporte de nutrientes, os quais são determinantes para a produção primária. As regiões de plataforma (Santa Marta-SC 28,60ºS e Albardão-RS 33,20ºS) foram selecionadas por apresentarem características diferenciadas em relação à topografia, sazonalidade e dinâmica das massas de água. Sendo assim, essas possuem diferentes mecanismos de fertilização, além dos aportes continentais. A proximidade à zona de Convergência Subtropical (CST) é determinante para a produtividade dessas regiões, visto que: no inverno, a intrusão da Água Subantártica de Plataforma na região do Albardão aumenta consideravelmente as concentrações de nutrientes na região e; no verão, a Água Central do Atlântico Sul resultado da CST aflora na região de Santa Marta, sendo responsável por 60% da produção nova local. Além disso, aportes subterrâneos foram evidenciados tanto na zona costeira quanto na região de plataforma. No extremo sul do Brasil verificou-se, mediante a variação espaço-temporal de isótopos naturais de rádio e radônio, a ocorrência de advecção de água subterrânea ao longo de toda a costa, desde a desembocadura da Lagoa dos Patos até as proximidades do Uruguai (média: 2,17± 0,2 cm d-1). Com a aplicação de modelos pré-estabelecidos, foi possível calcular os fluxosde nutrientes para a zona costeira (NIT: 21 105 mol d-1) e avaliar o potencial produtivo relacionado a essas descargas (2800 gC m-2 ano-1). Desse modo, entende-se que a parcela de água subterrânea deva ser definitivamente incluída no balanço de massas da região, uma vez que apresenta um potencial produtivo de 7 a 32 vezes maior quando comparado às outras regiões onde a estimativa foi realizada.
High productivity on the coastal region and on the Southern Brazil Continental Shelf is provided by the nutrient input which is fundamental to primary productivity. The regions of Santa Marta, SC (28.60ºS) and Albardão, RS (33.20ºS) were selected due to their special characteristics regarding the topography, seasonality and dynamics of their water mass. Therefore, these areas have different fertilization mechanisms besides the continental input. The proximity to the subtropical convergence zone (SCZ) is determinant in relation to productivity because, in winter, the intrusion of the Subantarctic Shelf Water (SSW) in the Albardão region considerably increases the nutrient concentration whereas, in summer, the South Atlantic Central Water (SACW) that results from the SCZ, moves to the Santa Marta region and is responsible for 60% of the new local production. In addition, subterraneous input was observed both on the coastal areas and on the shelf. In southern Brazil, spatial - time variations of radionuclides (Ra e Rn) show the occurrence of groundwater advection along the coast, from the mouth of Patos Lagoon to Uruguay rates (average: 2.17± 0.2 cm d - 1). Using mathematical models, it was possible to calculate the discharge of nutrients on the coastal zone (TIN: 21105 mol d - 1) and evaluate the productive potential regarding the Submarine Groundwater Discharge (2800 gC m - 2 y - 1). Thus, this study suggests that the portion of ground water should definitely be included in the mass budget of the region, since its productive potential is 7 to 32 times higher by comparison with other regions where this estimate was also carried out.
Tuerena, Robyn Elizabeth. "Nitrogen and carbon cycling in the South Atlantic Ocean : a stable isotope study along a 40°S transect (UK GEOTRACES)." Thesis, University of Edinburgh, 2015. http://hdl.handle.net/1842/10443.
Full textJakubczyk, Dorota [Verfasser], and S. [Akademischer Betreuer] Bräse. "Synthesis of isotope labelled and photoactivatable N-acyl-L-homoserine lactones - inter kingdom signalling molecules / Dorota Jakubczyk. Betreuer: S. Bräse." Karlsruhe : KIT-Bibliothek, 2013. http://d-nb.info/1041665539/34.
Full textNISHIYAMA, PEDRO J. B. de O. "Análises neutrônica e termo-hidráulica de um dispositivo para irradiação de alvos tipo LEU de UAlsub(x-)Al para produção de sup(99)Mo no reator IEA-R1." reponame:Repositório Institucional do IPEN, 2012. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10158.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
Sumrall, Jonathan. "Using 34-S as a tracer of dissolved sulfur species from springs to cave sulfate deposits in the Cerna Valley, Romania." [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002833.
Full textBleasdale, Madeleine [Verfasser], Nicole [Gutachter] Boivin, Martin S. [Gutachter] Fischer, and Matthew [Gutachter] Collins. "Archaeological, proteomic and isotopic approaches to investigating dietary change in Holocene Africa / Madeleine Bleasdale ; Gutachter: Nicole Boivin, Martin S. Fischer, Matthew Collins." Jena : Friedrich-Schiller-Universität Jena, 2020. http://d-nb.info/1225397391/34.
Full textCrépin, Lucie. "Variabilité dans l’utilisation de l’azote chez /Saccharomyces cerevisiae et conséquence sur la production de biomasse en fermentation œnologique." Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20258.
Full textThe completion of alcoholic fermentation is correlated with the level of biomass formation, which varies depending on the S. cerevisiae yeast strain. Achieving a better control of the fermentation requires a better understanding of the relationship between nitrogen metabolism and biomass formation and of the mechanisms contributing to variation in biomass formation between strains. The analysis of the kinetics of consumption of 18 nitrogen compounds showed that the order of consumption of nitrogen sources is similar for 14 strains and is mainly due to the kinetic characteristics and mode of regulation of permeases involved in their transport. By cons, variations are observed in the patterns of nitrogen consumption, which involve different mechanisms depending on the availability of nitrogen in the medium. In the presence of excess nitrogen, "low producing" strains have a limited capacity for assimilation of ammonium; when nitrogen is present in small quantities, they metabolize more efficiently arginine stored in the vacuole during the growth phase. To determine the intracellular distribution of nitrogen fluxes, we developed a quantitative approach based on isotopic filiation of 13C or 15N labeled nitrogen sources. This study revealed a limited incorporation of exogenous amino acids in biomass in favor of de novo synthesis, with the exception of leucine mostly integrated in the biomass and arginine stored in the vacuole. Finally, this study confirmed experimentally that the capacity of ammonium assimilation and remobilization of arginine are key determinant governing the differences of biomass production between strains. This study sheds new light on the efficient use and allocation of complex nitrogen sources during wine fermentation and on the mechanisms involved in the differences in biomass production within the S. cerevisiae species
Daou, Fatma. "Etude expérimentale d'un procédé de dépollution par décharge couronne à barrière diélectrique type pointe(s) - plan : rôle de la simulation numérique et du marquage isotopique." Paris 6, 2002. http://www.theses.fr/2002PA066488.
Full textGOMES, Ernane Tarcisio Martins. "Caracteriza??o qu?mica e estrutural de ?cidos h?micos em solos de tr?s sistemas de manejo." Universidade Federal Rural do Rio de Janeiro, 2016. https://tede.ufrrj.br/jspui/handle/jspui/2098.
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CNPq
Soil organic matter can be derived from the decomposition of animal or vegetable. Most commercial crops show photosynthetic mechanisms C3 and C4, which set different carbon isotopes C12 or C13. Through isotopic analysis can determine the origin and prevalence of type of carbon that make up the soil organic matter (SOM) in a given area. Depending on the chemical fractionation MOS can also be divided into fractions FAF, FAH and FHU, these fractions have specific characteristics depending on their origin training and ambient conditions. The objective of this study was to evaluate the influence of plant origin C3 or C4 in the formation of the chemical and molecular structure of humic substances extracted from four areas with different vegetation cover, but submitted to agroecological management. To investigate this influence were extracted humic substances (HS) of these soils, being held chemical fractionation and chemical characterization by NMR analysis, FTIR, quantification and ?13C e ?15N isotopes in the AH fraction, 13 C-CP / MAS NMR and elemental determination. From the results obtained from these analyzes it was concluded that the plant does not influence qualitative differences, but in quantitative between the chemical components of humic substances (HS), the type of photosynthetic cycle does not seem to be a determining factor in the formation and incorporation of the types of structures in HA, but rather the quantities of these structures and their humic organizational distribution. The chemometric theoretical analyzes indicate that the development and preservation of humic these soils may be possible in intensive management systems such as rotation upon application of exogenous sources of stabilized SH, as well as favoring the humidification process in less managed systems as pasture and SAF. In this study it was demonstrated by characterization and chemometrics applied to AH of an agro-ecological system, the current state of MOS in terms of stability and structural enrichment and being proposed possible avenues for recovery and preservation of SH in mineral soils that may contribute to the increase in conditions fertility and thus agricultural production.
A mat?ria org?nica do solo pode ser oriunda da decomposi??o de animais ou vegetais. A maioria das culturas comerciais apresentam mecanismos fotossint?ticos C3 ou C4, que fixam diferentes is?topos de carbono C12 ou C13. Atrav?s de an?lises isot?picas ? poss?vel determinar a origem e predomin?ncia do tipo de carbono que comp?em a mat?ria org?nica do solo (MOS) em determinada ?rea. Em fun??o do fracionamento qu?mico a MOS ainda pode ser dividida nas fra??es FAF, FAH e FHU, estas fra??es apresentam caracter?sticas especificas em fun??o da sua origem de forma??o e condi??es ambientes. O objetivo deste trabalho foi avaliar a influ?ncia da origem vegetal C3 ou C4 na forma??o da estrutura qu?mica e molecular das substancias h?micas extra?das de quatro ?reas com cobertura diferentes vegetais, por?m submetidas ao manejo agroecol?gico. Para averiguar esta influ?ncia foram extra?das as substancias h?micas (SH) destes solos, sendo realizado o fracionamento qu?mico e caracteriza??o qu?mica atrav?s de an?lises de RMN, FTIR, quantifica??o de is?topos ?13C e?15N na fra??o de AH, 13C-CP/MAS NMR e a determina??o elementar. A partir dos resultados obtidos a partir dessas an?lises foi poss?vel concluir que a origem vegetal n?o influencia em diferen?as qualitativas e sim em quantitativas entre os componentes qu?micos das substancias h?micas (SH), o tipo de ciclo fotossint?tico n?o parece ser um fator determinante na forma??o e incorpora??o dos tipos de estruturas nos AH, mas sim nas quantidades destas estruturas e na sua distribui??o organizacional h?mica. As an?lises te?ricas quimiom?tricas indicam que a incorpora??o e preserva??o de MO humificada nestes solos pode ser poss?vel em sistemas de manejo intensivo como a rota??o, mediante aplica??es de fontes ex?genas de SH estabilizada, assim como tamb?m o favorecimento dos processos de humifica??o em sistemas menos manejados como pastagem e SAF. Neste estudo foi comprovado mediante carateriza??o e quimiometria aplicadas aos AH de um sistema agroecol?gico, o estado atual da MOS em termos de estabilidade e enriquecimento estrutural e sendo propostas poss?veis vias para a recupera??o e preserva??o das SH em solos minerais que possam contribuir ao aumento das condi??es de fertilidade e consequentemente da produ??o agr?cola.
Walli, Adam. "Biomimetic Copper(I)-Mediated Activation of Dioxygen and Redox Non-Innocence in Copper(II) Complexes of Bis(oxazoline)s." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://hdl.handle.net/11858/00-1735-0000-0023-9636-9.
Full textKoutit, Abbès. "Reactions chaudes entre atomes de tritium et composes inorganiques (h : :(2)o, h::(2)s, nh::(3))." Université Louis Pasteur (Strasbourg) (1971-2008), 1986. http://www.theses.fr/1986STR13029.
Full textBreillat, Noémie. "Traçage des minéralisations à molybdène à l'échelle mondiale : variation du δ₉₈Mo en complément des outils isotopiques Pb, S, Re-Os." Thesis, Orléans, 2015. http://www.theses.fr/2015ORLE2079/document.
Full textThis study focuses on isotopic composition of molybdenite (MoS₂) in order to decipher possible links between occurrence type, mineralizing processes, ages and observed δMo variations. A data base (n=391) have been built thanks to data from this study and data from literature allowing to run solid statistics on Mo isotopic composition of MoS₂. Different occurrence types have been investigated (granite, pegmatite, greisens, perigranitic vein, porphyry deposit, skarn, IOCG, polymetallic epithermal vein and alpine-type fissure vein). All δ₉₈Mo have been normalized to NIST3134 (δ₉₈MoNIST(NIST) = 0‰). The distribution of all data is Gaussian with a mean value of 0.04±1.04‰ (2σ). δ₉₈MoNIST mean values are higher for alpine-type fissure vein, greisens and perigranitic vein than for skarn, granite and porphyry deposit. These last occurrence types crystallize at higher temperature. For granite-related occurrences, δ₉₈MoNIST of granite is lower than δ₉₈MoNIST of pegmatite and perigranitic vein. This suggests an influence of temperature on Mo isotopic fractionation. Intra-occurrence variations have been evidenced. The intra-occurrence variations are not depending of the occurrence type. δ₉₈MoNIST of the Azegour skarn vary on large range of 1.02‰. Rayleigh fractionation is proposed as principal fractionation process. S and Pb isotopic analyses suggest a contribution of hosting volcano-sedimentary series. δ₉₈MoNIST of Ploumanac’h pegmatite vary on a narrow range of 0.22‰. S and Pb isotopic analyses suggest a strong crustal contribution in magmas genesis
NGOM, ELHADJI ABIB. "Contribution a l'etude des spectres infrarouges de quelques rotateurs asymetriques d : :(2)s, d::(2)o, no::(2)." Paris 6, 1987. http://www.theses.fr/1987PA066552.
Full textHutton, Laurie James. "Petrogenesis of I- and S-type Granites in the Cape River - Lolworth area, northeastern Queensland - Their contribution to an understanding of the Early Palaeozoic Geological History of northeastern Queensland." Thesis, Queensland University of Technology, 2004. https://eprints.qut.edu.au/15858/1/Laurie_Hutton_Thesis.pdf.
Full textHutton, Laurie James. "Petrogenesis of I- and S-type Granites in the Cape River - Lolworth area, northeastern Queensland - Their contribution to an understanding of the Early Palaeozoic Geological History of northeastern Queensland." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15858/.
Full textThomas, B. P. "Gypsum cements in Cenozoic sediments in the Murray Basin, South Australia: their age and origin." Thesis, 1999. http://hdl.handle.net/2440/119336.
Full textA maximum Pleistocene (~0.6 Ma) age has been assigned to surface and sub-surface gypsum cements occurring in the Norwest Bend Formation and Upper Morgan Limestone, in the western Murray Basin. The gypsum cements post date the draining of Lake Bungunnia and the formation of the Murray River Gorge. The chemical and morphological diversity exhibited by the gypsum forms indicates a variety of genetic processes. Three main gypsum facies can be distinguished by their structural fabrics, which are indicative of the environmental conditions in which they formed. (1) Bedded gypsum crusts (selenite) and gypsum nodules have fibrous to lenticular crystals and occur as discrete horizons along sections of the Murray River cliffs. (2) Massive crystalline gypsum contain poikilitic inclusions of elastic material, indicating they formed below the surface where long periods of stable brine conditions allowed for large crystal growth. (3) Aeolian seed gypsum dunes derived from the deflation of gypsum from modem playa lakes. Sulphur and Strontium isotopes, fluid inclusion studies, and geochemical analysis (XRD) and (XRF), were used to interpret the brine conditions under which the different gypsum facies formed. Fluid inclusion analysis was used to determine the palaeosalinity of the brines from which the gypsum precipitated. The melting temperatures of ice in fluid inclusions indicate that brine salinities and compositions were similar to brines derived from evaporated sea water. They also indicate that gypsum crusts formed from less saline water than selenite and gypsum nodules. The delta34S ratios of gypsum crusts are also close to seawater values (+17.9%0 to +20.2%0 CDT), indicating marine sulphate is the dominant source of sulphur. Strontium isotope data negate the possibility of derivation of the lacustrine "seawater like" brine chemistry, from either marine transgressions or weathering of connate salts from marine strata alone. Sulphur and Sr isotope ratios of the gypsum crusts indicate that gypsum was predominantly derived from the dissolution of the aeolian gypsum dunes by meteoric water influenced by sea spray. The demise of Lake Bungunnia indicated the onset of aridity in Southern Australia. The draining of the megalake may be responsible for the gypsum cements and the aeolian gypsum dunes from which they were derived.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1999
Ryan, S. J. "The geology and genesis of the polymetallic Wagga Tank prospect, Mount Hope, N.S.W." Thesis, 1987. http://hdl.handle.net/2440/105306.
Full textThe Wagga Tank Prospect is located in Central Western N.S. W, 125 km south of Cobar. The prospect is hosted by the Lower Devonian Mount Hope Group, a complex succession of sedimentary, felsic volcanic and comagmatic intrusive rocks representing the oldest division of the Cobar Supergroup in the Mount Hope area. The prospect is primarily a Pb and Zn deposit with minor Cu, Ag and significant Au. Gold values are highest within steeply dipping gossan shoots in the oxidised zone, while Pb and Zn values are highest in subvertical shoots of massive sulphide within the primary zone. Cu is concentrated as chalcocite, digenite and malachite at a zone of supergene enrichment. The primary mineralization occurs within a zone of intense tectonic brecciation and argillic alteration at a pronounced flexure along the steeply dipping contact between the volcaniclastic sequence and a siltstone - slate sequence. The mineralization can be divided into two categories on the basis of textural relationships, i.e. fine grained, crudely banded massive type sulphides and coarser grained vein type sulphides. The vein type sulphides are represented by varying proportions of pyrite, chalcopyrite, sphalerite and galena with rare inclusions of cubanite and pyrrhotite. The massive type sulphides show mineral abundances of pyrite>sphalerite>galena>>chalcopyri te. Fluid inclusion and chlorite data indicate that the mineralizing fluid reached temperatures of about 325°C. Sulphur isotope compositions of the sulphide minerals (delta 34S = 10 per mil) suggest that the sulphur originated from seawater SO4-2. Reduction of seawater SO4-2 to H2S was primarily by an inorganic process at elevated temperatures in a heated rock pile. Thermodynamic calculations suggest possible log f02 - pH constraints of about log f02 = -29. 5 to -31. 7 and pH = 3 to 4. 5 for the mineralizing fluid. The mineralization is considered to be of epigenetic hydrothermal origin. The hydrothermal fluid was probably derived from dewatering of the rock pile during metamorphism accompanying the major deformation. Sulphide precipitation occurred along a plane of high permeability produced by folding of adjacent beds with a contrasting competency. The prospect bears many similarities to the principal deposits in the Cobar area. Those deposits are typically narrow steeply plunging elongate bodies occurring along sheared or brecciated contacts between cleaved turbiditic siltstones and coarser clastic beds or felsic volcanics.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 1987
Dogramaci, Shawan Shawket. "Isotopes of sulphur, oxygen, strontium and carbon in groundwater as tracers of mixing and geochemical processes, Murray Basin, Australia / by Shawan Shwket Dogramaci." Thesis, 1998. http://hdl.handle.net/2440/19296.
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Salinisation of groundwater and surface water of the semi-arid Murray Basin is an issue of vital importance to the viability of agriculture in south-east Australia. The understanding of the transport and transfer of water and salts in large sedimentary aquifers is necessary for better management of water resources in the future. Assesses the usefulness of [detla]34S and [delta]18OSO42 of dissolved SO42- and 87SR/86Sr ratios as tracers of inter-aquifer mixing and rock-water interaction between and within the Murray and Renmark Group aquifers in the south-west Murray Basin.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1999?
Thomas, B. J. "Trace elements in magnetite and hematite for improving pathfinder element selection of the Hillside copper mineralisation, Yorke Peninsula." Thesis, 2010. http://hdl.handle.net/2440/106278.
Full textThe Hillside deposit is located in the southern part of the Olympic Province on the Gawler Craton, South Australia. This area has a history of IOCG-U style deposits, including the world class Olympic Dam deposit. Several other deposits and prospects have also been identified within this Olympic Dam domain. The Hillside deposit was discovered in the 1800s but recent work by Rex Minerals has expanded the mineralisation zone and have categorised this deposit as part of the IOCG-U family. A prominent characteristic of the Hillside IOCG mineralisation is the conversion of magnetite to hematite which in previous works on IOCG-U deposits was shown to be related to the mineralisation process. Two main mineralizing episodes can be distinguished, an earlier one was extremely Fe rich and allowed the formation of magnetite and pyrite. The second stage of mineralisation involved the injection of copper mineralizing fluids concurrent with the widespread replacement of magnetite by hematite. Analysis of the iron oxides was carried out using optical methods as well as trace element and rare earth element analysis by Electron Probe Micro Analysis and Laser Ablation ICP MS. The trace elements were used to identify compositional signature variations between the different iron oxide minerals. The rare earth element analysis showed a distinct overall enrichment in the hematite samples compared to the magnetite. The trace element analysis showed that several elements are distributed differently between the two oxides and sulphides. These elements include Cr, Zn, V, Ti, Ni, Pb and Co which show anomalies in both the oxides and sulphides. A variation between what elements are enriched is dependent on the mineral they are found within. This is suggested to reflect changes in composition of the mineralising fluid from the early magnetite-pyrite to the late hematite-chalcopyrite stage. The sulphides showed that chalcopyrite was enriched in several trace elements compared to pyrite. Sulphur isotope data were derived for pyrite and chalcopyrite also to characterise the source of the fluids. There was no systematic difference between chalcopyrite and pyrite. The data did show negative values between -2.6 δ34S and -6.6 δ34S which indicates that the source of the sulphur is most likely magmatic. This study gives an indication into the change in conditions that caused the replacement of magnetite by hematite and therefore the changes that caused mineralisation. An element signature was also collected to identify the difference between the iron oxides that will help in future works on this deposit.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2010