Дисертації з теми "Copper isotope"

Depuis la fin du 19ème siècle, le traitement des vignes par des fongicides cupriques a engendré une augmentation de la teneur en cuivre (Cu) dans les sols viticoles, ainsi que dans les écosystèmes aquatiques en aval. Cette thèse vise à mieux comprendre le devenir de ce Cu dans un agrosystème basé sur l’étude du fractionnement isotopique du 65Cu/63Cu. Les résultats montrent que durant 4 à 5 décennies de culture de vignes, les sols en surface se sont enrichis en Cu de 9 à 28 fois par rapport au fond géochimique et que les minéraux argileux jouent un rôle important dans l’accumulation du Cu. Lors des événements pluvieux, ~1% du Cu appliqué est mobilisé, essentiellement lié à des argiles. Le bassin d’orage récoltant les lames ruisselantes retient en moyenne 68% du Cu dissous et plus de 92% du Cu particulaire. Les ratios isotopiques du Cu dans le bassin indiqueraient la sorption du Cu dissous dans les sédiments, ainsi que la réduction du Cu(II) in situ due à des processus biogéochimiques
Since the end of the 19th century, the use of copper (Cu)-based fungicides has resulted in increased Cu concentrations in vineyard soils, but also in downstream aquatic ecosystems. The aim of the thesis was to better understand the fate of this Cu in an agrosystem based on assessing Cu isotope fractionation (65Cu/63Cu). The results have shown that the surface vineyard soils have become enriched in Cu from 9 to 28 times compared to the background level during 4 to 5 decades of vine-growing and that clay minerals were the major Cu sorbing phases in the soils. During rainfall, runoff mobilized ~1% of the applied Cu during the, mainly associated with clays. The stormwater wetland collecting the runoff retained in average 68% of the dissolved and more than 92% of particulate Cu. Cu isotope ratios measured in the wetland suggested dissolved Cu sorption to the sediments and in situ reduction of Cu(II) due to biogeochemical processes

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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

The nature of Cu isotope fractionation in natural Cu-Fe-S minerals was investigated through acid ferric sulfate leaching of copper ore from Morenci, Arizona. Copper isotope composition of the derived solutions varies from δ⁶⁵Cu = 0.47‰ to 5.21‰ over the course of progressive copper extraction. High δ⁶⁵Cu values characterize solutions collected in the first half of the leach, while the solutions collected between 35% and 45% copper recovery exhibit lower δ⁶⁵Cu values. This general pattern was observed for both bacterially-mediated and abiotic leaching. Sulfate solutions derived from dissolving pure djurleite show variable Cu isotope compositions as well, although the range is protracted from δ⁶⁵Cu = 0.01‰ to 1.21‰. As the Cu:S ratio of the remaining sulfide decreases, crystal structure parameters change as mineralogy passes through a series of nonstoichiometric copper sulfides. Mineralogy converges to yarrowite near 44% copper dissolution. Crystal chemical studies show that distribution of the two copper-sulfur bond coordination geometries, triangular planar and tetrahedral, in the copper sulfides, approximately corresponds to changes in δ⁶⁵Cu of the leachates. In particular, the proportion of CuS3 relative to CuS4 groups decreases from Cu/S = 2.00 (chalcocite) to 1.40 (geerite). Between Cu/S = 1.40 to 1.00 (covellite), the relative proportion of CuS3 groups increases slightly. Connection between coordination number and Cu isotope fractionation implies affinity of CuS₃ groups for the heavier, ⁶⁵Cu, isotope. This can be justified through bond length-bond strength arguments. Solutions from bornite dissolution vary from δ⁶⁵Cu = -0.79‰ to 1.14‰, with the largest values associated with solutions from early stage of reaction (up to 15% copper removal). Around 25% dissolution, δ⁶⁵Cu of the solution approaches that of the original bornite (δ⁶⁵Cu = 0.02‰). This is explained by disappearance of all remaining CuS₃ groups. Sulfur isotope compositions of solutions and sulfides derived from djurleite leaching were determined to investigate the possibility of intra-mineral fractionation. Very soon after reaction initiation, δ³⁴S of both sulfur reservoirs reach a steady-state with sulfate solutions about 2‰ enriched in ³⁴S relative to residual sulfide. Unlike the case of Cu isotopes, the main partitioning affecting S isotopes is exchange between sulfate and sulfide.

Master of Science
Department of Geology
Matthew E. Brueseke
Mid-Miocene epithermal Au-Ag ores of the northern Great Basin USA are related to magmatism associated with the inception of the Yellowstone hotspot. The geochemical chemical connection between these ores and spatially and temporally related volcanism is not well understood, but has been suggested (Kamenov, 2007; Saunders et al., 2015). These Cu- and Pb- isotope studies show that the ore and associated gangue minerals have different sources of Pb, which supports evidence that the metal(loids) originate from a deep magmatic source (Saunders et al., 2008). Cu isotopes as a tool for exploring linkages between ore deposits and related volcanic rocks is a new and evolving field. A suite of mid-Miocene Northern Great Basin (NGB) and Snake River Plain (SRP) volcanic rocks was analyzed by aquaregia leach for their δ⁶⁵Cu compositions. These samples have all been previously characterized and include basalts, trachybasalt, basaltic andesites, and basaltic trachyandesites that are representative of regional flood basalt magmatism and younger basalt eruptions in central Idaho. Included are rocks from the Santa Rosa-Calico volcanic field, NV (e.g., Buckskin-National district); Owyhee Mountains, ID (Silver City District); Midas, NV region, near Jarbidge, NV; and a locality proximal to Steens Mountain, OR. Also included are two Pleistocene basalts from the central Snake River plain unequivocally related to the Yellowstone hotspot volcanism (McKinney Basalt and Basalt of Flat Top Butte), and one Eocene basalt from the Owyhee Mountains that is related to pre-hotspot arc volcanism. International rock standards ranging from ultramafic to intermediate were also analyzed in this study for comparison. Our new δ⁶⁵Cu data greatly expands the range of known Cu isotopic compositions for basalts, with values ranging from -0.84‰ to +2.61‰. These values overlap with the δ⁶⁵Cu of regional ores, further suggesting a link between the source(s) of the ores and the NGB rocks. The range of δ⁶⁵Cu values also overlaps with mantle rock values, suggesting that the Cu isotopic composition may be a signature derived from the mantle source. Fractionation mechanisms that cause such a broad range in Cu isotopes are still unclear but liquid-vapor transitions and mantle metasomatism are being explored. Furthermore, δ⁶⁵Cu values of international rock standards reported in this study did not agree with previously reported data (Archer and Vance, 2004; Bigalke et al., 2010; Moeller et al., 2012; Liu et al., 2014, 2015) suggesting that aquaregia leach may not be a preferable technique when analyzing volcanic rocks.

The provenance of metal artifacts in the early history of metallurgy has been a major question in archaeology for many decades. Pb isotope ratios (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) are commonly used for provenancing in archaeometry, but interpretations are hardly debated and sometimes ambiguous because natural ore deposits frequently show overlapping Pb isotopic compositions. The first way to reduce observed overlaps is by improving the analytical precision. The second way to reduce ambiguities is to combine the lead isotopic signature with other geochemical indicators, e.g. minor and trace elements or other isotopic data. Extraction of reliable provenance information from a combination of several geochemical tracers, however, requires sophisticated statistical analysis. Here, more than 350 samples were collected from 50 mining areas. Some of the most important copper districts in the central-eastern Southern Alps (Variscan basement and Permian-Triassic cover, Carnic Alps), in the Western Alps (Piedmont Zone, Ligurian Briançonnais, Gran Paradiso nappe, Argentera), in the Ligurian Apennines (Libiola, Monte Loreto) and the Southern Tuscany (Isola d’Elba, “Colline metallifere” and Montecatini Val di Cecina). About 270 samples of primary (copper and copper-iron sulfides and copper sulphosalts) and secondary (supergenic copper carbonates and oxides and native copper) raw minerals and archaeological finds (slags, copper and bronze artifacts of Chalcolithic to Late Bronze Age) were analyzed for lead isotopes and minor and trace elements (including most transition metals and chalcophile elements and the REE). Moreover, the feasibility of the routine measurement of the 65Cu/63Cu isotope ratio and its use as a possible ore tracer was also tested. An advanced statistical investigation (PCA, PLS-DA, NPC) has been carried out on the database to provide discriminant statistic tools for metal provenancing. The samples were first characterized mineralogically and petrologically (XRD, RL-OM), and then analysed by ICP-QMS (Inductively Coupled Plasma-Quadrupolar Mass Spectrometry) for trace elements and 65Cu/63Cu isotopic ratios. Multicollector ICP mass spectrometry (MC-ICP-MS) was used to determine precise Pb isotopic ratios (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb). The chemical/isotopic dataset of the mines was analysed with Principal Component Analysis (PCA) and Partial least Square-Discriminant Analysis (PLS-DA). The chemical and isotopic data were arranged into a bidimensional matrix characterized by samples (objects) in the rows and the chemical measurement as the variables in the columns. The dataset was also analysed with the Nonparametric Combination (NPC) test, which is an inferential multivariate nonparametric method that frees from the stringent assumptions of parametric methods (such as t and F test) and allows a more flexible analysis both in terms of specification of multivariate hypotheses and in terms of the nature of the variables involved. One of the most important advantages of applying nonparametric statistics like permutation tests, is that it allows one to relax the assumption of normality of response variables. Moreover, the NPC Test does not requires modelling of dependence among variables and is not affected by the problem of loss of degrees of freedom when the number of variables is large compared to sample size. Results of NPC Test analysis were obtained using the free software NPC Test R10, where as test statistic we used the F-test and as combining function we used the Fisher combining function (Pesarin, 2001). The results can be graphically represented by PCA. The availability of an unprecedented and comprehensive amount of geochemical data for Alpine copper deposits yielded information relevant to their metallogenic interpretation. In particular, the isotopic compositions of trace lead in copper-bearing hydrothermal sulphide deposits from the central-eastern Southalpine region were combined with existing lead isotope data for hydrothermal polymetallic deposits in the same area and compared with the isotopic compositions of potential lead sources. Copper and polymetallic pre-Variscan (Late Ordovician–Early Silurian) stratiform, post-Variscan (Permian to Triassic) vein, and stratabound sediment-hosted (Permian to Early Triassic) deposits, are characterized by highly variable ratios of radiogenic to non-radiogenic lead, but show very similar, high, time-integrated  (= 238U/204Pb) and W (= 232Th/204Pb) values. A progressive relative increase in radiogenic lead is observed from (i) pre-Variscan deposits to (ii) post-Variscan sulphide-rich veins in the Variscan metamorphic basement and in the lower–intermediate units of the Early Permian volcanic sequence to (iii) post-Variscan sulphide-rich and fluorite-rich veins in the upper units of the Early Permian volcanic sequence to (iv) post-Variscan fluorite-rich veins cutting the overlying Late Permian sediments and mid-Triassic mafic dikes. The dominant lead sources for all these deposits were Cambrian–Devonian (meta)sediments of the Variscan basement. Contributions from Permian and Triassic igneous rocks were of minor importance, if any, even for vein deposits which were evidently related to Permian magmatism While Pb isotopic fingerprinting could potentially help identify the likely provenance of an archeological object, there are a number of related difficulties. First of all, natural ore deposits frequently have overlapping Pb isotopic compositions. So, trace elements, Rare Earth Elements and 65Cu/63Cu isotopic ratios were investigated in addition to lead isotopes. Copper 63Cu/65Cu isotopic ratio is sensitive to the temperature of mineral segregation; therefore, it provides information on the nature of the mineral used for the object manufacturing. A statistical selection was carried out to detect the variables that more effectively distinguish the investigated ores. This was achieved using a PLS-DA strategy. This technique is a classification method that models the differences between two classes. The PLS method calculates a linear regression model between the predictors matrix (X) and the response vector (Y): in this particular case the Y vector is expressed with the binary code. The model provides scores and loading plots as well as the regression coefficient for each variable. An estimate of the statistical significance of these regression coefficients is also provided. The statistical relevance of the variables was tested through the Martens Uncertainty test. The study of the correlation loadings and the model coefficients led to the definition of a variable subset capable to discriminate the samples coming from the different mining sites/areas. A single model was not sufficient and a multi-step exclusion strategy was required to attain a satisfactory discrimination. The procedure adopted can be summarized as follows: 1) the whole data set is taken into account and a PCA model is built. Through the study of the score plots generated by the combination of the first principal components (usually PC1 to PC4) the most effectively discriminated locality is chosen for the exclusion process; 2) the next step is the variable selection in order to emphasize the differences between the selected locality and all other localities: the aim is to build a simple discriminant model using only PC1 or no more than two PCs; 3) the data related to the selected locality are excluded from the original matrix and the whole process is then repeated on this reduced matrix initially considering again all the variables. The discriminating power of the database was tested for the provenancing of copper metals and slags from the Agordo area (BL) and of prehistoric copper fragment and slags from Millan (Bressanone, BZ). The samples were projected onto an existing PCA model, and their position compared with the position of the samples used to build the model. The same projection method was also used for the validation of the multiple step exclusion strategy. Data for copper artifacts and slags from the Agordo area show that the discriminant model that best identifies the Agordo ores is perfectly applicable to the objects, clearly indicating that the metal was extracted from the local ores. For the Millan case, the discriminating model of the deposits that best describes the copper fragment is the one that identifies the Val Venosta area (Oris, Val Martello, and Stelvio mines), located 80 km to the west of the archaeometallurgical site of Millan. This result suggests that the copper sample is genetically unrelated to the large amount of associated slags produced during the smelting of copper from local sphalerite/galena-rich chalcopyrite ores, which have a significantly different mineralogical and geochemical character. A successful strategy to characterize copper ores and to trace the provenance of copper minerals and ancient copper objects was presented. A whole analytical protocol starting from the sampling to the quantitative analysis was developed to ensure geologically sound and good quality analytical data. The measurements of a wide group of elements including the Rare-Earth Elements (REE) together with the lead and copper isotopic ratio in Cu minerals allowed a full geochemical characterization of the investigated Cu-ores. The data collected were used to build a database that can be used as the fundamental reference frame for tracing of metal extraction and diffusion in the past. Application of advanced statistical techniques to the geochemical and isotopic data proved to be a powerful tool to discriminate the ore source areas. The presented applications to copper metal samples and slags seem to confirm that the analysis can be successfully performed on archaeometallurgical specimens. The availability of such an unprecedented and comprehensive amount of data for Alpine copper deposits also yield interesting information for their geochemical and metallogenic interpretation. In particular, the high  and W values of the deposits from the central-eastern Southalpine are consistent with regional isotopic patterns of Pb–Zn-rich deposits in more northerly and easterly sectors of the Eastern Alps (Austroalpine, eastern Southalpine) and of several circum-Mediterranean Pb–Zn and polymetallic deposits of Paleozoic to Triassic age (Sardinia; Betic Cordillera) or derived from remobilization of Paleozoic deposits (Tuscany). This isotopic uniformity suggests the existence of an isotopic province characterized by the dominance of old (Early Proterozoic to Archean) detrital source material, extending across a relatively wide portion of the former north-Gondwanan margin.
La provenienza di manufatti metallici nella prima storia della metallurgia è stata il maggiore problema in archeologia per molte decadi. I rapporti isotopici del Pb (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb) sono comunemente usati per definire la provenienza dei manufatti in archeometria, ma le interpretazioni sono fortemente dibattute e qualche volta ambigue dal momento che i depositi naturali mostrano di frequente composizioni isotopiche del Pb sovrapposte. Il primo modo di ridurre le sovrapposizioni osservate è di aumentare la precisione analitica. Il secondo modo di ridurre le ambiguità è di combinare la segnatura isotopica del piombo con altri indicatori geochimici, ad esempio con altri dati isotopici o di elementi minori e in traccia. L’estrazione di un’informazione di provenienza affidabile dalla combinazione di numerosi traccianti geochimici, tuttavia, richiede analisi statistiche sofisticate. Qui più di 350 campioni sono stati raccolti da 50 aree minerarie. Alcuni dei più importanti distretti di rame nella porzione centro-orientale delle Alpi meridionali (Alpi Carniche, copertura Permo-Triassica e basamento Varisico), nelle Alpi occidentali (Zona Pedemontana, Brianzonese Ligure, nappe del Gran Paradiso, Argentera), negli Appennini Liguri (Libiola, Monte Loreto) e nella Toscana meridionale (Isola d’Elba, “Colline metallifere” and Montecatini Val di Cecina). Sono stati analizzati circa 270 campioni di minerali grezzi primari (rame, solfuri di rame-ferro e solfo-sali di rame) e secondari (carbonati e ossidi di rame supergenico e rame nativo) e ritrovati archeologici (scorie, manufatti di rame e bronzo di età da Calcolitica a Tardo Bronzo) per analisi degli isotopi del piombo e degli minori e in tracce (inclusi la maggior parte dei metalli di transizione, elementi calcofili e terre rare). Inoltre è stata testata la fattibilità di misure di routine del rapporto isotopico del Cu (65Cu/63Cu) e del suo possibile uso come tracciante delle miniere. E’ stata eseguita un’avanzata analisi statistica (PCA, PLS-DA, NPC) su un database per ottenere strumenti statistici discriminanti per la provenienza dei metalli. I campioni sono stati prima caratterizzati mineralogicamente e petrologicamente (XRD e RL-OM) e successivamente analizzati mediante tecnica ICP-QMS (Spettrometri di Massa Quadrupolare mediante Plasma accoppiato induttivamente) per gli elementi in tracce e i rapporto isotopico 65Cu/63Cu. E’ stata usata la spettrometria di massa multicolletore (MC-ICP-MS) per la determinazione precisa dei rapporti isotopici del piombo (206Pb/204Pb, 207Pb/204Pb, 208Pb/204Pb). L’insieme di dati chimico/isotopico delle miniere è stato analizzato con l’Analisi delle Componenti Principali (PCA) e con l’Analisi Discriminante dei minimi quadrati parziali (PLS-DA). I dati chimici e isotopici sono stati inseriti in una matrice bidimensionale caratterizzata dai campioni (manufatti) nelle righe della matrice e le analisi chimiche come variabili nelle colonne. L’insieme dei dati è stato inoltre analizzato con il test della Combinazione non-parametrica (NPC), che è un metodo non-parametrico multivariato inferenziale che libera dalle stringenti assunzioni dei metodi parametrici (come il t e F test) e permette un’analisi più flessibile sia in termini della specificazione di ipotesi multivariate, sia in termini della natura della variabili in causa. Uno dei più importanti vantaggi dell’applicare statistiche non-parametriche come i test di permutazione, è che permette di lasciare libera l’assunzione di normalità delle variabili di risposta. Inoltre, il Test NPC non richiede la modellazione della dipendenza tra le variabili e non è affetta da problemi di perdita di gradi di libertà quando il numero di variabili è grande comparato al numero dei campioni. I risultati dell’analisi del Test NPC sono stati ottenuti usando il programma libero NPC Test R10, dove abbiamo usato l’F-test come test statistico e la funzione di combinazione Fisher come funzione combinante. I risultati possono essere rappresentati graficamente mediante la PCA. La disponibilità di una comprensiva e senza precedenti quantità di dati geochimici per i depositi Alpine di rame ha dato informazioni rilevanti per la loro interpretazione metallo genica. In particolare, le composizioni isotopiche delle tracce di piombo nelle mineralizzazione a rame in depositi di solfuri idrotermali della regione sudalpina centro-orientale sono state combinate con i dati degli isotopi del piombo di depositi poli-metallici idrotermali esistenti nella stessa area, e comparati con le composizioni isotopiche di potenziali sorgenti di piombo. Depositi stratiformi di rame e poli-metallici pre-Varisici (tardo Ordoviciano - primo Siluriano), depositi a vene post-Varisiche (da Permiano a Triassico) e depositi a stratabound ospitati in sedimenti (da Permiano al primo Triassico) sono caratterizzati da rapporti altamente variabili di piombo radiogenico e non, ma mostrano valori di  (= 238U/204Pb) e W (= 232Th/204Pb) molto simili e alti. Si osserva un relativo progressivo aumento in piombo radiogenico dai (i) depositi pre-Varisici alle (ii) vene ricche di solfuri post-Varisiche presenti nel basamento metamorfico Varisico e nelle unità inferiori-intermedie della sequenza vulcanica per primo Permiano alle (iii) vene post-Varisiche ricche in fluorite e solfuri nelle unità superiori della sequenza vulcanica del primo Permiano alla (iv) vene post-Varisiche ricche in fluorite che tagliano i sovrastanti sedimenti tardo-permiani e i dicchi mafici medio-triassici. Le sorgenti di piombo dominanti per tutti questi depositi sono i (meta)sedimenti del Cambriano-Devoniano del basamento Varisico. Contributi da rocce ignee permiane e triassiche sono di minore importanza, se presenti, anche per depositi di vena che sono evidentemente correlati con il magmatismo permiano. Mentre l’impronta isotopica del Pb potrebbe potenzialmente aiutare la probabile provenienza del manufatto archeologico, ci sono numerose difficoltà correlate. Prima di tutto, i depositi naturali hanno frequentemente composizioni isotopiche del Pb sovrapposte. Così in aggiunta agli isotopi del Pb sono stati analizzati gli elementi in tracce, terre rare e rapporti isotopici del rame (65Cu/63Cu). Il rapporto isotopico del rame 65Cu/63Cu è sensibile alla temperature di segregazione del minerale; quindi fornisce informazioni sulla natura del minerale usato per la produzione del manufatto. E’ stata operato una selezione statistica per identificare le variabili che più effettivamente distinguono le miniere investigate. Questo è stato raggiunto usando una strategia PLS-DA. Questa tecnica è un metodo di classificazione che modella le differenze tra due classi. Il metodo PLS calcola un modello di regressione lineare tra la matrice dei predittori (X) e il vettore risposta (Y): in questo particolare caso il vettore Y è espresso con un codice binario. Il modello restituisce scores and loading plots così come il coefficiente di regressione per ogni variabile. Viene inoltre fornito una stima del significanza statistica di questo coefficienti di regressione. La rilevanza statistica delle variabili è stata testata attraverso il Martens Uncertainty test. Lo studio delle matrici di correlazione e dei coefficienti del modello permette di definire un sotto-insieme di variabili in grado di discriminare i campioni provenienti dalla differenti aree/siti. Un singolo modello non è stato sufficiente ed è stata richiesta una strategia di esclusione a più passaggi per ottenere una discriminazione soddisfacente. La procedura adottata può essere schematizzata come segue: 1) l’intero insieme di dati è preso in considerazione e viene creato un modello PCA. Attraverso lo studio dei score plots generato dalla combinazione delle prime componenti principali (in genere da PC1 a PC4) la località maggiormente discriminante viene scelta per il processo di esclusione; 2) il passo successivo la selezione della variabile con l’intento di enfatizzare le differenza tra la località selezionata e tutte le altre località: l’obiettivo è costruire un semplice modello discriminante usando solo PC1 o non più di due PCs: 3) i dati correlati alla località selezionata sono esclusi dalla matrice originale e l’intero processo è quindi ripetuto su questa matrice ridotta inizialmente considerando di nuovo tutte le variabili. Il potere discriminante del database è stato testato sulla provenienza di metalli e scorie di rame provenienti dall’area di Agordo (Belluno) e di frammenti e scorie di rame preistorici provenienti da Millan (Bressanone, Bolzano). I campioni sono stati proiettati in un modello PCA esistente, e la loro posizione comparata con la posizione dei campioni usati per costruire il modello. Lo stesso metodo di proiezione è stato inoltre usato per la validazione della strategia di esclusione a passaggi multipli. I dati per manufatti e scorie di rame proveniente dall’area di Agordo mostrano che il modello discriminante che meglio identifica le miniere di Agordo è perfettamente applicabile ai manufatti, indicando chiaramente che il metallo è stato estratto dalle miniere locali. Per il caso di Millan, il modello discriminante dei depositi che meglio descrive il frammento di rame è quello che identifica l’area della Val Venosta (miniere di Oris, Val Martello e dello Stelvio), localizzate 80 km a ovest del sito archeometallurgico di Millan. Questo risultato suggerisce che il campione di rame è geneticamente non correlato alla grande quantità di scorie associate prodotte durante il processo di smelting del rame provenienti dalle locali miniere di calcopirite ricche di sfalerite e galena, che hanno un carattere mineralogico e geochimico significativamente differente. E’ presentata una strategia vincente per caratterizzare miniere di rame e per tracciare la provenienza di minerali e antichi manufatti di rame. E’ stato sviluppato un intero protocollo di controllo, che parte dal campionamento all’analisi quantitativa, per assicurare una corrispondenza geologica e una buona qualità dei dati analitici. Le misure di un vasto numero di elementi che include le terre rare (REE) insieme con i rapporti isotopici del rame e del piombo in minerali di rame ha permesso una completa caratterizzazione geochimica delle miniere a rame investigate. I dati raccolti sono stati usati per costruire un database che può essere usato come riferimento fondamentale per tracciare l’estrazione del metallo e la sua diffusione in passato. L’applicazione di avanzate tecniche statistiche ai dati geochimici e isotopici fornisce uno strumento potente per discriminare le aree delle miniere sorgenti. Le applicazioni presentate relativamente ai campioni e scorie di rame sembrano confermare che le analisi possono essere operate con successo su campioni archeometallurgici. La disponibilità di un tale ammontare di dati esaustivo e senza precedenti per i depositi di rame alpini inoltre da informazioni interessanti per la loro interpretazione geochimica e metallogenica. In particolare, gli alti valori di  e W dei depositi del sud-alpino centro-orientale sono consistenti con andamenti isotopici regionali dei depositi a Pb-Zn in settori più settentrionali e orientali delle Alpi orientali (Australoalpino, Sudalpino orientale) e di numerosi depositi metallici e a Pb-Zn dell’area mediterranea di età paleozoica fino a triassica (Sardegna, Cordigliera Betica) o derivati da rimobilizzazione di depositi paleozoici (Toscana). Questa uniformità isotopica suggerisce l’esistenza di una provincia isotopica caratterizzata da una preponderanza di vecchio materiale sorgente detritico (primo Proterozoico fino ad Archeano), che si estende attraverso una relativamente estesa porzione di un più recente margine nord-Gondwaniano.

The distribution of the stable isotopes of Cu and Fe in nature is susceptible to isotope fractionation processes during the biogeochemical cycle. Since Cu and Fe are redox sensitive metals, differences in their oxidation states can lead to variations in the stable isotope composition of the aquatic species or compounds that they form. Stable isotopes of Cu and Fe have recently been used to trace metal redox cycles, nutrient pathways, metal contaminant sources and to develop isotopic biosignatures. The objective of this project was to study the geochemical processes governing the isotopic fractionation of Cu and Fe in mine impacted sites, including processes related to mineral processing. One of the key questions was to explain the role of bacteria in the variations of the isotopic composition of Cu and Fe. First, bioleaching and electroleaching of a chalcopyrite concentrate were performed. During the chalcopyrite leaching in both experiments the first release of Cu to the leachate is enriched in the heavier Cu isotope as a product of oxidative dissolution. At the later stages of leaching, the δ65Cu values for the leachate are similar to the initial material, confirming an equilibrium fractionation in a closed system. In the case of Fe isotope fractionation the dissolution of pyrite at redox potentials higher than 600mV leads to an enrichment of the heavier Fe isotope in the leachate in the bioleaching experiment, mainly regulated by the formation of secondary minerals such as jarosite. Soil bacteria were studied in three different experimental scales using pot, lysimeters and field experiments, amended with autochthonous plant growth promoting bacteria. Roots and plants from pots showed no variation in their Fe and Cu isotope composition compared to non-amended samples. However, plants growing in the amended substrates regardless of their experimental scale, showed variations in the Fe and Cu isotope composition of their roots with an increase in the heavier Cu isotope. Siderophores released either by bacteria or the plant can complexate available Cu and Fe in the soil, causing a change in the isotope fractionation of those metals. The second question is related to the biogeochemical cycle of Cu and Fe. In mine tailings the sulphide oxidation resulted in an enrichment of the lighter Cu isotope in secondary phases in the oxidized zone of the tailings compared to the original isotope composition in the unoxidised mineral. Precipitation of covellite at the oxidation front of the tailings profile resulted in a significant enrichment of the lighter Cu isotope in the bulk soil with a δ65Cu value as low as -4.35 ±0.02 ‰. Fe isotope fractionation in the Kristineberg test cell varied due to processes such as Fe(II)-Fe(III) equilibrium and precipitation of Fe-(oxy)hydroxides at the oxidation front, where δ56Fe values were higher than in the initial material. As a way to link the obtained results from this thesis, a self-restored mine site was studied. A variation towards higher δ65Cu values was seen from rocks, to water and biofilms. Cu absorption mainly by extrapolymeric substances and secondary mineral precipitation regulates the isotopic composition of the biofilm. Oxidative weathering of sulphide minerals and further precipitation of Fe-(oxy)hydroxides are considered to be the main causes for Fe isotope fractionation in this area. Summing up, this thesis provides several field studies to corroborate the data observed in the lab regarding processes that are important for the biogeochemical cycling of metals and could be further applied to the extraction of metals or for remediation purposes.
Godkänd; 2013; 20131028 (natper); Dissertation to be held in public in room E632 on Tuesday 17th of December at 10:00 am. External examiner: Dr. Dominik Weiss, Department for Earth Sciences and Engineering, Imperial College London. Chairman: Professor Björn Öhlander, Division of Geosciences and Environmental Engineering, Luleå University of Technology. --- Tillkännagivande disputation 2013-11-22 Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Nathalie Pérez Rodríguez Ämne: Tillämpad geologi/Applied Geology Avhandling: Biotic and Abiotic Isotope Fractionation of Copper and Iron. From the Lab to the Field Scale Opponent: Dr Dominik Weiss, Reader, Department of Earth Science & Engineering, Imperial College of London, UK Ordförande: Professor Björn Öhlander, Institutionen för samhällsbyggnad och naturresurser, Luleå tekniska universitet Tid: Tisdag den 17 december 2013, kl 10.00 Plats: E632, Luleå tekniska universitet

Gas chromatography mass spectrometry (GCMS) and inductively coupled plasma mass spectrometry (ICPMS) were evaluated for the measurement of selenium (Se) and Se stable isotope ratios. GCMS and ICPMS were found to be accurate for quantitative Se analysis in biological matrices by isotope dilution using Se-78 and Se-76 as internal standards, respectively. A higher precision was obtained for ICPMS than GCMS enabling a smaller quantity of the tracer to be administered to subjects in labelling experiments. The isotopes of choice for metabolic tracers were Se-76 when sample analysis was by GCMS and Se-77 and Se-82 when analysis was by ICPMS. The influence of copper (Cu) on endogenous fecal Se excretion and true absorption of Se in nonlactating Holstein cows was examined by the use of Se stable isotopes as tracers. The method involved the application of conventional balance techniques in conjunction with isotopic enrichment of the body Se pools. Selenium in several tissues following oral and intravenous routes of isotope administration were evaluated as the precursors of endogenous fecal Se. Two cows fed a Se deficient diet (0.035 mg kg⁻¹) were administered 4 mg Se-76 orally, daily, for 5 d. After a 10-d equilibration period total collection of feces was made daily for two 5-d periods. The animals were then sacrificed and samples obtained from all major tissues and fluids. Se-7 6 enrichment (tracer/tracee mass percent, TTMP) in tissues was variable (< 0.56 - 13.4). However, enrichment was similar (9.8 - 12.9) in the tissues considered as potential contributors to endogenous fecal Se (serum, epithelium of the stomach, liver, bile, pancreas, small intestine and colon). Enrichment in serum and liver was used to calculate endogenous fecal Se. Apparent absorption of Se in the two cows was negative (-37 and -147 µg d⁻¹). Correction of apparent absorption for the fecal Se of endogenous origin gave a true Se absorption (% of intake) of 10 and 16%. The percentage of total fecal Se of endogenous origin was 23 and 36%. In two trials, 5 or 6 cows were assigned to one of two Cu-supplemented treatment diets: 0 mg kg⁻¹ or 17 mg kg⁻¹. The basal diet contained 0.19 mg Se kg⁻¹ and 13 mg Cu kg⁻¹. To each cow ~4.6 mg Se-77 and ~1.3 mg Se-82 were administered by oral and intravenous routes, respectively. After a 14-d equilibration period, total collection of feces and urine were made daily for two 5-d periods. Serum was collected on the first, third and fifth days of each period. Liver biopsies were taken 2 d following the completion of the balance periods. The estimates of endogenous fecal Se ( d⁻¹) from enrichment in the serum (256) and liver (235) following oral administration of the tracer and from enrichment in serum (241) following intravenous administration were not significantly different (P>0.05) but were higher than the estimate from the enrichment in liver (197) (P<0.05). No significant differences (P>0.05) were present when true absorption ( µg d⁻¹) was determined from enrichment in serum (290) or liver (268) following oral administration or from enrichment in serum (274) or liver (230) following intravenous administration. It was concluded the analysis of serum or liver with oral administration or the analysis of serum with intravenous administration of the tracer would provide reliable methods for estimation of endogenous fecal Se and true absorption. There was no effect of Cu on endogenous fecal Se excretion or true absorption of Se. Apparent and true absorption were 3.2 and 11%, respectively. Approximately 90% of the total Se excreted was in the feces, of which, 9.7% was of endogenous origin. The use of Se stable isotopes as metabolic tracers in dairy cattle provided a safe alternative to the use of radioactive tracers and enabled experiments requiring multi-isotopic enrichment to be performed.
Land and Food Systems, Faculty of
Graduate

Morenci is located in southeast Arizona. Copper grade hypogene mineralization averages 0.15%; one or more generations of supergene enrichment have increased mineralization to 0.96%. Intense supergene alteration has made it difficult to determine phyllosilicate paragenesis. The purpose of this study is to differentiate hypogene from supergene phyllosilicates. Forty-nine samples from five drill holes were obtained for petrographic, geochemical, mineralogical, and stable isotope data. Petrographic examination, X-ray diffraction and X-ray powder camera techniques established alteration of feldspars to kaolinite, montmorillonite, and sericite. Whole rock analyses using XRF determined cationic gains and losses that correspond with kaolinite and sericite. Stable isotopes of oxygen and hydrogen using kaolinite and sericite from 14 samples were tested to determine provenance of water. Stable isotope data show a trimodal distribution of phyllosilicates consistent with early hypogene alteration of magmatic origin, and two generations of supergene enrichment due to meteoric waters.

The Abhainn Srathain copper mineralisation with at least 10 million tonnes of rock containing copper was worked during the Eighteenth Century and is situated 1-2km to the south of Meall Mór, South Knapdale. The mineralisation is hosted by epidiorites, quartzites and schists of the Upper Erins Quartzite Formation in which the levels of copper reach up to 2%, 1.3% and 0.8% respectively. The main suiphide phases, pyrite and chalcopyrite, occur in disseminations, in layers and as large crystals in quartz and/or calcite cross-cutting veins. The observed opaque mineral textures are due to recrystallisation, deformation and limited mobilisation indicating a premetamorphic origin for the mineralisatlon. Microscopic compositional variation of the minerals and isotopic geothermometry of analysed pyrite-chalcopyrite pairs suggest disequilibriun conditions during the regional metamorphism. Sulphides contain low minor element concentrations with a high Co:Ni ratio in pyrite (12.5:1). The mineralisation is associated with the local development of epidote, Mn-rich garnet, chlorite, muscovite and calcite and/or quartz cross-cutting veins which all resulted from premetamorphic alteration during ore formation. During this alteration CaO, Fe₂0₃, CO₂, MnO, Cu, S and some trace elements were added, Al₂0₃ was diluted and MgO, FeO, alkalis and some trace elements were removed. The isotopic composition of bacteriogenically reduced sulphur from sulphides throughout the Knapdale Pyrite Horizon ranges between o³⁴s=+4.5 and 12.8 per mil. The consistent isotopic values of the suiphides from the Abhainn Srathain copper mineralisation with an average of around +7 per mil regardless of location, depth, lithology and style of mineralisation suggest that the source of the hydrothermal sulphur is a mixture of inorganically reduced downward percolating Dalradlan seawater sulphate and sulphur leached from interbedded basic igneous rocks. Weak exhalative activity caused by the shallow intrusion of sill bodies into the wet unlithified sediments of the Lower and Upper Erins tiartzite accompanied the deposition of the Upper Erins Quartzite and is expressed by weak disseminated and stratiform pyrite with traces of chalcopyrite and sphalerite (Knapdale Pyrite Horizon). Increasing intensity of this exhalation was due to the creation of a geothermal system centred at the site of the present copper mineralisation. During this stage the hot ascending water reacted with the rocks causing local alteration and precipitation of pyrite and chalcopyrite as disseminations, layers and cross-cutting veins. At the same time cold water descended into the hot intrusives and altered the rocks by dissolving silica and precipitating calcite and oxides.

Since the early stages in the study of ancient metals, one important goal was to establish the geological origin of the metal employed to produce artefacts, with the intent to deduce the issues of trade, the commercial relationships and the movements of objects. Recently, a number of studies carried out by different research groups have expanded the traditional/conventional chemical and metallographic analyses by including the measurement of lead isotopic ratios, in order to determine the metal provenance. Although a deep interest for Friuli Venezia Giulia has been shown since the beginning of 19th century, a systematic research program that could define the metal circulation routes of Alpine copper in North-Eastern Italy has never been carried out. Actually, only sporadic chemical analyses on ingots found in Friuli have been performed and, until now, the interpretation of their provenance is not supported by isotopic data. In this frame, the archaeometric study of copper and bronze artifacts from several well-dated protohistoric hoards in Friuli Venezia Giulia has allowed for the investigation of the origin of the metal, by identifying the ores exploitation areas and, therefore, has permitted to reconstruct its circulation paths in North-Eastern Italy in the Late Bronze Age. The choice of Friuli as investigation area was due to its key role as economic and commercial hub between the Adriatic area and Central Europe; therefore, in order to outline the role of this region, the study of sealed complexes embracing the time period from the Recent Bronze Age (RBA) to the Final Bronze Age (FBA) was needed. In this regard, the hoards of Cervignano, Muscoli, Castions di Strada, Celò, Verzegnis, Galleriano and Porpetto, all of them including both raw ingots and manufactured objects, were identified and selected in collaboration with the Soprintendenza per i Beni Archeologici del Friuli Venezia Giulia. There are no known hoards from the MBA and, therefore, two sporadic finds – one sword from Belvedere and one from Canale Anfora – have been properly selected in order to increase the number of samples representative of this period. In the present work, a multi-analytical approach was applied. Particular relevance was given to the study of chemical composition (major, minor and trace elements) and to the observation of any residual phases due to an incomplete refinement of the raw material, since these information may shed light on the employed Cu-ore charge and on their smelting process, but are often insufficient to surely identify the exploitation area of the metal. For this reason, such investigation methods were coupled with lead isotopes analysis carried out on selected samples. Therefore, the set of mineralogical, metallurgical, chemical and isotopic analyses, through a comparison with existing Pb-isotope databases, published data and the Alpine Archaeocopper Project database (AAcP) allowed for the identification of the provenance of the metal. The results showed that ingots are basically made of almost copper and, only in few cases, of bronze, containing impurities whose concentrations depend on the mineral charge and on the employed extraction/refinement process. Moreover, weapons were found to be subject to a deliberate alloying process with the intent to obtain a malleable bronze. The large set of analyses collected in this study has led to the distinction of two mineral charges, used in well defined metallurgical circles, indeed, chalcopyrite-based deposits were exclusively exploited during Recent/Final Bronze Age (RBA/FBA) for the manufacturing of the ingots and objects of the Cervignano and Muscoli deposits, although few evidences are also documented in the later periods. In this scenario, a change in the mineral charge was revealed in Castions di Strada (FBA), attesting the restart of fahlerz-ores smelting, also confirmed by the findings belonging to the Porpetto hoard that, moreover, exhibited a chemical affinity to Slovenian cast ingots. The provenance studies have highlighted that, from the MBA to the whole FBA, the Eastern South Alps were known and constantly exploited for smelting chalcopyrite in order to obtain pure copper ingots and, subsequently, prestige objects as weapons and tools. Only in the FBA, the copper from new ore sources (Austria, Central Europe and Bulgaria) was employed and its flow has been proven in Friuli Venezia Giulia. Concerning the metal trade, the bronze circulation in RBA was testified by the little bar-ingots that, in FBA2, assumed the well-known shape of pick-ingots as evidenced in Galleriano. However, the peculiar composition of the Porpetto pick-ingots has demonstrated that such standardized ingot was circulating independently from the alloy composition, but probably in well-distinguished commercial spheres.
Fin dalle prime fasi della ricerca archeometallurgica, un obiettivo importante è stato quello di determinare l'origine geologica del metallo impiegato per la produzione di manufatti, con l'intento di ricostruire i rapporti commerciali e il circuito di circolazione degli oggetti. Recentemente, diversi gruppi di ricerca hanno fatto ricorso, oltre alle tradizionali analisi chimiche e metallografiche, anche alle analisi dei rapporti isotopici del piombo per determinare il più accuratamente possibile la provenienza del metallo. Fin dall'inizio del 19° secolo il Friuli Venezia Giulia ha suscitato un profondo interesse, ma non è mai stato intrapreso un programma di ricerca sistematico in grado di definire i percorsi di circolazione del rame alpino nell’Italia Nord-Orientale. Infatti, solo sporadiche analisi chimiche sono state eseguite su alcuni lingotti ritrovati in Friuli e, fino ad ora, la loro interpretazione in termini di provenienza del metallo non è supportata da alcun dato isotopico. In questa cornice, lo studio archeometrico di manufatti di rame e bronzo provenienti da vari rispostigli protostorici ben datati del Friuli Venezia Giulia ha permesso di indagare l'origine del metallo utilizzato, individuando le aree sfruttamento dei minerali e, di conseguenza, di ricostruirne la circolazione nell’Italia Nord-orientale nella tarda Età del Bronzo. La scelta del Friuli come regione di interesse è dovuta al suo ruolo chiave come centro economico e commerciale tra l'area adriatica e l'Europa Centrale; pertanto, per delineare il ruolo di questa regione si è reso necessario lo studio di complessi ben sigillati che abbracciassero un range cronologico dal Bronzo Recente (BR) al Bronzo Finale (BF). A questo proposito, i depositi di Cervignano, Muscoli, Castions di Strada, Celò, Verzegnis, Galleriano e Porpetto, in cui sono contenuti sia lingotti che manufatti, sono stati individuati e selezionati in collaborazione con la Soprintendenza per i Beni Archeologici del Friuli Venezia Giulia. Non ci sono ripostigli noti per il Bronzo Medio (BM) e, quindi, due ritrovamenti sporadici - una spada da Belvedere e una da Canale Anfora - sono stati selezionati con l’intento di aumentare il numero di campioni rappresentativi di questo periodo. Nel presente lavoro è stato applicato un approccio multianalitico. Particolare rilevanza è stata attribuita allo studio della composizione chimica (elementi maggiori, minori e in traccia) e all'osservazione di eventuali fasi residue dovute a un raffinamento incompleto della materia prima; tali informazioni possono far luce sul tipo di carica minerale impiegata e sulla tecnologia del processo di fusione, tuttavia sono insufficienti per identificare sicuramente l'area sfruttamento del metallo. Per questo motivo, tali metodi di indagine sono stati accoppiati con l’analisi degli isotopi del piombo ed effettuati su una selezione di campioni considerati rappresentativi. Pertanto, l'insieme delle analisi mineralogiche, metallurgiche, chimiche e isotopiche, attraverso il confronto con i database esistenti per gli isotopi del piombo, i dati pubblicati in letteratura e il database sviluppato all’interno dell’ Alpine Archaeocopper Project (AAcP) ha consentito l'identificazione della provenienza del metallo. I risultati hanno mostrato che i lingotti sono fondamentalmente costituiti da rame e, solo in pochi casi, da bronzo; le concentrazioni degli elementi minori e in traccia dipendono dalla carica minerale e dal processo impiegato per l’estrazione e il raffinamento. Inoltre, le analisi hanno rivelato che le armi sono state alligate intenzionalmente con lo scopo di ottenere un bronzo malleabile. La grande quantità di dati raccolti in questo studio ha portato alla distinzione di due cariche minerali utilizzate in ambienti metallurgici ben definite; infatti, i depositi caratterizzati da calcopirite sono stati sfruttati in maniera esclusiva durante Bronzo Recente-Finale per la produzione dei lingotti e degli oggetti dei depositi di Cervignano e Muscoli, mentre sporadiche testimonianze sono documentate nei periodi successivi. In questo scenario, in Castions di Strada (BF) si riscontra un cambiamento nella carica minerale e, conseguentemente, viene attestata la ripresa nell’uso di minerali fahlerz; inoltre, questa inversione di tendenza è stata confermata anche dai risultati riguardanti i materiali scoperti a Porpetto che hanno mostrato una spiccata affinità chimica con i lingotti sloveni. Gli studi di provenienza hanno evidenziato che dal Bronzo Medio al Bronzo Finale evoluto le Alpi Sud-orientali erano costantemente sfruttate per l’estrazione di rame da calcopirite, con l’intento di ottenere lingotti di rame puro e, successivamente, oggetti di prestigio come armi e strumenti. Solo nel Bronzo Finale, si assiste all’impiego di il rame estratto da nuovi depositi minerali (Austria, Europa centrale e Bulgaria), la cui circolazione è stata dimostrata in Friuli Venezia Giulia. Inoltre, nel Bronzo Recente la circolazione del bronzo è testimoniata dal ritrovamento di piccoli lingotti a barra che, nel Bronzo Finale hanno assunto la forma ben nota dei pani a piccone, come evidenziato in Galleriano. Tuttavia, la particolare composizione dei pani a piccone di Porpetto ha dimostrato che tale lingotto circolava con forma standard indipendentemente dalla composizione della lega, probabilmente in sfere commerciali ben distinte.

This thesis describes the use of kinetic isotope effects, linear free energy relationships and stereochamical studies to distinguish between different mechanistic alternatives and to obtain information about transition state structure. In the first part fluorine and deuterium kinetic isotope effects were determined for the base promoted HF elimination from 4-fluoro-4-(4’-nitrophenyl)butane-2-on. During this work a new method for the determination of fluorine kinetic isotope effects was developed. The results from the study demonstrates that the reaction proceeds via an E1cBip mechanism. In the second part the transition state structure for the SN2 reaction between ethyl chloride and cyanide ion in DMSO was studied. Kinetic isotope effects for six different positions in the reacting system, both in cyanide and ethyl chloride, were determined. The experimental isotope effects were then compared with the theoretically predicted isotope effects. The third part describes the use of Hammett type free-energy relationships and stereochemical evidence to study the mechanism of the copper catalysed alkene aziridination. The results from the study support a model that involves the simultaneous presence of two different copper nitrene intermediates. One which reacts non-stereospecifically via a radical intermediate and one which reacts stereospecifically via a concerted mechanism. In the fourth part a mechanistic study of the Ru(aminoalcohol) catalysed transfer hydrogenation of acetophenone in isopropanol is described. Kinetic isotope effects were determined for both proton and hydride transfer. The observation of significant primary deuterium kinetic isotope effects for both proton and hydride transfer support a mechanism where the proton and hydride are transferred simultaneously in a concerted mechanism.

Les conditions oxydantes de la surface terrestre actuelle sont dues à la teneur élevée en dioxygène de l’atmosphère. Au début de l’histoire de la Terre il y a 4.54 milliards d'années (Ga), l’oxygène n’était pas stable dans l’atmosphère. Il a fallu deux épisodes d’augmentation brutale de ce gaz atmosphérique pour qu’il atteigne son niveau actuel : l’un vers 2.4 Ga, nommé le Grand Evènement Oxydant (GOE) qui fait l’objet de ce projet, l’autre 2 milliards d’années plus tard, nommé l’Evènement Oxydant Néo-protérozoïque (NOE). Le GOE est vraisemblablement le résultat de l’émersion généralisée de larges continents dont l’érosion libère le phosphate dans l’océan, un nutriment nécessaire à la production biologique, qui a donc permis l’explosion de la photosynthèse oxygénée. Ces deux hausses d’oxygène atmosphérique coïncident avec deux évolutions majeures dans l’histoire de la vie : (i) peu après le GOE, les eucaryotes sont apparus, alors que (ii) le NOE correspond à l’apparition des métazoaires et à l’explosion cambrienne. L’étude de ces phénomènes atmosphériques primitifs peut avoir d’importantes répercussions sur notre compréhension de l’origine et de l’évolution de la vie, qu’on estime principalement marine à cet âge. Les seules archives de ces temps primitifs sur Terre sont les roches sédimentaires. Pour savoir comment l’oxygénation de l’atmosphère a pu être reliée à cette vie marine, il faut tout d’abord comprendre comment l’océan a interagi avec l’atmosphère lors de cet évènement d’oxygénation. Cette question est au coeur de ce projet : comment le GOE a-t-il affecté les cycles biogéochimiques océaniques dont la vie est dépendante ? Nous nous sommes intéressés aux formations ferrifères litées ou BIFs (Banded Iron Formations). La chimie de ces roches marines fait écho à celle de l’océan contemporain à leur formation. Déterminer quantitativement la composition de l’océan à partir de celles des sédiments, même chimiques, est un défi quasiment impossible à relever y compris dans l’océan moderne. C’est pourquoi nous avons proposé de déterminer le temps de résidence d’éléments sensibles aux conditions redox de la surface, le soufre, le fer et le cuivre dans l’océan pré-GOE. Nous avons obtenu, par des séries temporelles, le spectre des fluctuations isotopiques de ces éléments enregistrées dans des carottes de formations ferrifères litées. La limite inférieure du spectre donne le temps de résidence de ces éléments dans l’eau de mer et fournit donc une indication solide sur la teneur de ces éléments dans l’océan à cette période. Nous avons analysé des échantillons protérozoïques proches de la limite Archéen-Protérozoïque du Transvaal (Afrique du Sud) et d’Hamersley (Australie). Des échantillons eoarchéens de Nuvvuagittuq (Canada) ont été récoltés mais n'ont pas pu être analysés faute de temps
The present-day oxidizing conditions at Earth's surface are due to the high oxygen content of the atmosphere. However, oxygen was not always stable in the terrestrial atmosphere. Two distinct periods during which oxygen increased in a step-like manner were required to reach the current atmospheric oxygen level. The first, at about 2.4 Ga, is known as the Great Oxidation Event (GOE) and is at the core of this Ph.D. thesis. The other, occurring almost two billion years later, is called the Neo-Proterozoic Oxidation Event (NOE). The GOE likely is the result of the beginning widespread emergence of large continental expanses whose subsequent erosion gradually released phosphate into the ocean. Phosphate, a nutrient essential to organic production, in turn allowed the explosion of oxygenated photosynthesis. The GOE and NOE coincide with two major changes in the history of life. Shortly after the GOE, eukaryotes appeared, while the NOE corresponds to the appearance of metazoans and the Cambrian explosion. A better grasp of the GOE hence may have important implications for the understanding of the origin and evolution of life, which is thought to have been mainly marine at this stage in Earth history. The only records of the oxygen level during these ancient times are found in terrestrial sedimentary rocks. To understand how oxygenation of the atmosphere relates to marine life, we must first understand how the ocean was connected to the atmosphere during the GOE and how the GOE affected life-dependent ocean biogeochemical cycles. To this end we focused on banded iron formations (BIF). The chemistry of these sedimentary marine rocks directly reflects the chemistry of the contemporary ocean. Deriving quantitatively the composition of the ocean from a hydrogenous sediment is a challenge almost impossible to meet, even for the modern ocean. This is why we instead determined the residence time of redox-sensitive elements (in this case sulfur, iron, and copper) in the pre-GOE ocean. We specifically targeted the periods of isotopic fluctuations in these elements as recorded in BIF cores. The lower limit of the spectrum provides the residence time of these elements in seawater, hence giving a robust indication of their contents in the pre-GOE ocean. We sampled early Proterozoic BIF near the Archean-Proterozoic boundary in Transvaal (South Africa) and Hamersley (Australia), as well as Archean BIF from Nuvvuagittuq (Canada), though the latter were not analyzed during this thesis due to shortage of time

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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Bei der Schwefelquantifizierung in Kupfer und anderen reinen Metallen zeigte sich in der Vergangenheit eine mangelnde SI-Rückführung und zusätzlich inkonsistente Ergebnisse, wenn verschiedene Methoden verglichen wurden. Um diesen Mangel zu beheben ist ein Referenzverfahren erforderlich, welches SI-rückführbare Werte mit einem zuverlässigen Unsicherheitsbudget ermöglicht. In dieser Studie wurde ein entsprechendes Referenzverfahren zur Quantifizierung von Gesamtschwefel in Kupfer basierend auf der induktiv gekoppelten Plasma-Massenspektrometrie und der Isotopenverdünnungsanalyse (ICP-IDMS) entwickelt. Um diese Probleme zu lösen wurde mit Hilfe der Ionenaustauschchromatographie ein Schwefel-Matrix-Trennverfahren entwickelt. Dieses Trennverfahren wurde mit ICP-IDMS kombiniert, um Schwierigkeiten mit der Kalibrierung zu lösen und fehlende metrologische Konzepte einzuführen. So wurden die in diesem Projekt erzielten IDMS-Messwerte für die Kalibrierung von GDMS und LA-ICP-MS verwendet, beides Verfahren die im industriellen Einsatz üblich sind. Dadurch konnten mit beiden Routineverfahren zuverlässige Ergebnisse erzeilt warden, die zudem auf SI rückführbar sind. Darüber hinaus wurde ein auf der LA-ICP-IDMS basierendes Verfahren entwickelt, um den Probenvorbereitungsschritt von ICP-IDMS mit Schwefel-Matrix-Trennung zu reduzieren. Die Vorteile dieser Methode sind ein geringerer Arbeits- und Zeitaufwand, die SI- Rückführung der Messergebnisse und eine für LA-ICP-MS vergleichsweise hohe Genauigkeit. Die Schlüsselrolle hierbei spielte der innovative Einsatz von Polyethylenfritten als Trägermaterial der aufgelösten Probe. Dadurch war die Quantifizierung von Schwefel in Kupferproben mittels LA-ICP-IDMS möglich. Die wesentlichen Parameter wie Absorptionseffizienz der Fritten und Matrixeffekt wurden untersucht. Das entwickelte Verfahren konnte mit Hilfe der ICP-IDMS vollständig validiert werden.
Sulphur quantification in copper and other pure metals in the past revealed a lack of SI-traceability and also showed inconsistent results, when different methods are compared. Therefore, a reference procedure is required to enable SI-traceable measurement results accompanied by a sound uncertainty budget. In this study, such a procedure was developed for the quantification of total sulphur in copper using inductively coupled plasma-isotope dilution mass spectrometry (ICP-IDMS). For solving these problems ion exchange chromatography was applied, and a sulphur-matrix separation procedure was developed. This procedure was combined with ICP-IDMS to solve difficulties with the calibration and to realize metrological concepts. An application of the IDMS procedure was realized by using the measurement results of specific copper samples values for calibrating glow discharge mass spectrometry (GDMS) and laser ablation ICP-MS (LA-ICP-MS). Both techniques are considered routine techniques. Thus, they could provide reliable results which are traceable to the SI. Additionally, a procedure based on LA-ICP-IDMS was developed to significantly reduce the sample preparation step of ICP-IDMS with sulphur-matrix separation. This procedure is less laborious and the measurement results are still SI traceable and offer a comparatively high accuracy for LA-ICP-MS. Key for this development was the innovative application of polyethylene frits as support material for the dissolved sample. Thus, the quantification of sulphur in copper samples by LA-ICP-IDMS could be realized. The essential parameters are investigated such as the absorption efficiency of the frit and matrix effects. The developed procedure was fully validated by means of the ICP-IDMS results.

Use of Re-Os systematics in sulfides from the Bagdad porphyry Cu-Mo deposit provide information on the timing of mineralization and the source of the ore -forming elements. Analyzed samples of pyrite, chalcopyrite and molybdenite mainly from the quartz monzonite and porphyritic quartz monzonite units are characterized by a moderate to strong potassic alteration (secondary biotite and K- feldspar). Rhenium concentrations in molybdenite are between 330 and 730 ppm. Two molybdenite samples from the quartz monzonite and porphyritic quartz monzonite provide a Re-Os isotope age of 71.7 ± 0.3 Ma. A third sample from a molybdenite vein in Precambrian rocks yields an age of 75.8 ± 0.4 Ma. These molybdenite ages support previous suggestions of two mineralization episodes in the Bagdad deposit. An early event at 76 Ma and a later episode at 72 Ma. Pyrite Os and Re concentrations range between 0.008-0.016 and 3.9-6.8 ppb, respectively. Chalcopyrite contains a wide range of Os (6 to 91 ppt) and Re (1.7 to 69 ppb) concentrations and variable ¹⁸⁷Os/¹⁸⁸Os ratios that range between 0.13 to 22.27. This variability in the chalcopyrite data may be attributed to different copper sources, one of them the Proterozoic volcanic massive sulfides in the district, or to alteration and remobilization of Re and Os. Analyses from two pyrite samples yield an eight point isochron with an age of 77 ± 15 Ma and an initial ¹⁸⁷Os/¹⁸⁸Os ratio of 2.12. This pyrite Re-Os isochron age is in good agreement with the molybdenite ages. We interpret the highly radiogenic initial 1870s/188Os as an indication that the source of Os and, by inference, the ore-forming elements for the Bagdad deposit, was mainly the crust. This conclusion agrees with previous Pb and Nd isotope studies and supports the notion that a significant part of the metals and magmas have a crustal source.

Preparation de nitriles a partir d'amines primaires et d'alpha -aminoacides. Les acides amines monosubstutitues rch(nh::(2))co::(2)h donnent le nitrile rcn, alors que les acides amines disubstitues rr'c(nh::(2))co::(2)h conduisent a l'azine rr'c=n-n=cr'r. Les mecanismes proposes font intervenir le cuivre (iii), forme in situ a partir du cuivre (i) et de l'oxygene

Les potentiels de nouveaux moyens d’investigation en sciences de l’environnement, tel que la géochimie des isotopes stables du Cu et du Zn et l’étude de la spéciation des éléments en trace métalliques (ETM) par titrage acidimétrique sont évalués dans le cadre de trois cas d’études, faisant intervenir des matériaux de matrices et de concentrations en ETM variables. Afin de mettre en évidence de très subtiles variations des compositions isotopiques du Cu et du Zn dans les matériaux particulaires variablement pollués, une attention particulière à été voué à la mise au point des méthodes de séparation chimique et d’analyse par MC-ICP-MS. La méthodologie analytique a été développée afin d’exploiter tout les avantages techniques offerts par le spectromètre de masse à l’ULB. Différents modes d’introduction (plasma humide vs plasma sec (Aridus/DSN), d’acquisition des mesures (mode statique ou dynamique) de correction du biais de masse (dopage au Cu, au Zn et au Ga; correction SSBM, SSBC et EEN)ont été évaluées, pour leurs effets sur la précision et la reproductibilité des mesures. D’autres travaux ont permis de quantifier les effets des interférences spectrales et non spectrales par les éléments de la matrice (Ti, Cr, Co,Fe, Ba, Si, Na, Mg et Ca)et par le rapport dopant/analyte en vue de comprendre les sources d’inexactitudes des mesures isotopiques et d’y remédier. Les données isotopiques acquises sur des minerais, sur des (plaques de) dépôts atmosphériques (usine Pb-Zn Metaleurop de Noyelles-Godault), sur des sédiments et des matières en suspension (estuaire de l’Escaut et mer du Nord), révèlent des variations significatives des compositions isotopiques du cuivre et du zinc. Dans l’estuaire de l’Escaut, les variations temporelles (carotte non perturbée, enregistrant la sédimentation sur 30 ans) et spatiales (matières en suspension échantillonnées sur 100 km, selon le profil de salinité) sont caractérisées par des signatures isotopiques en Zn anticorrélées à celle du Cu. Les données peuvent permettre de distinguer le fond géochimique naturel (le « réservoir naturel »), les pollutions diffuses (le « réservoir anthropique commun »- intégrant de multiples sources de contamination en provenance du bassin versant) et certaines pollutions ponctuelles associées à la métallurgie du Zn. Alors que les procédés utilisés en métallurgie sont eux,capable de produire des signatures isotopiques très fractionnées en Zn, ni la diagenèse précoce dans les sédiments, ni les gradients physicochimiques développés lors du mélange des eaux continentales et marines ne sont capables d’affecter significativement la signature isotopique du Cu et du Zn en phase particulaire. Dans de tels milieux, les signatures isotopiques en Cu et Zn (ainsi que celles en Pb) semblent n’être contrôlées que par le mélange conservatif entre le « réservoir naturel » et le « réservoir anthropique commun ». Les données en elles-mêmes constituent la seule base de données isotopiques en Cu, Zn, Pb dans des matériaux particulaires anthropisés estuariens et marins jamais produite à ce jour. Elles permettent de prédire que la signature isotopique en Cu du « réservoir naturel » devrait être légèrement plus enrichie en isotopes lourds que celle du réservoir « anthropique commun » (par analogie au Zn).

Si la géochimie isotopique du Cu et du Zn a le potentiel de distinguer différentes sources de pollution, l’évaluation des risques liés à ces pollutions doit tenir compte des formes chimiques des ETM, typiquement mises en évidences par les méthodes d’extraction sélectives (séquentielles, dont le protocole BCR). La méthode alternative proposée pour l’étude de la spéciation, plus versatile (capable de mettre en évidence des phases non prédéfinies et applicable à une variété de matrices plus large) est capable de surmonter plusieurs limitations (dont les problèmes de sélectivité liées au mauvais contrôle de l’acidité du milieu réactionnel) caractéristiques des méthodes traditionnelles. Appliquée à des sédiments marins/estuariens et des sols, la méthode de titrage acidimétrique s’est révélée capable de quantifier les proportions relatives des phases acido-solubles (principal problème des méthodes d’extraction sélectives), ce qui permet d’établir univoquement la spéciation des éléments qui leurs sont associés, d’évaluer la réactivité des ETM vis-à-vis du pH, mais aussi d’évaluer la sélectivité des protocoles d’extraction séquentielle « BCR » et « Tessier ». La méthode de titrage acidimétrique apporte également des informations importantes sur la géochimie des éléments majeurs dans l’estuaire de l’Escaut et met en évidence les particularités minéralogiques des sols pollués en comparaison aux sédiments.

Les études de cas démontrent que ces nouvelles techniques ont des applications dans le domaine de la géochimie de l’environnement, mais peuvent également être vouées, sur le moyen/long terme à une utilisation sortant du cadre des sciences exactes. En effet, l’identification/discrimination des sources de pollutions et l’évaluation des risques de remobilisation des polluants métalliques font partie des nombreuses questions posées par la société aux scientifiques de l’environnement.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished

Mesozoic Cordilleran arc magmatism along the western margins of North and South America shows similar patterns of episodic activity, but differences in tectonic setting, in composition, and in peak magnitudes of magma fluxes. The development of iron oxide(-copper-gold) (‘IOCG’) mineralization accompanies the pulse of arc magmatism in North and South America, but is most prolific during the early to middle Mesozoic pre-orogenic phases of the Cordillera. The focus of this work is to better understand the episodic nature of Cordilleran magmatism, controls to magma sources and compositions, and controls to Cordilleran IOCG mineralization. The objectives of this study are accomplished by focusing on two regions of the Cordillera that experienced similar early-middle Mesozoic tectonic settings, but display very different magmatic fluxes, compositions, and development of IOCG systems. The Coastal Batholith of northern Chile was investigated for the timing, composition, and fluxes of magmatism at three scales of observation including 1:1M scale between ~18°S to 34°S, 1:100K scale between 26°S to 28°S, and 1:20K scale along a transect at ~27.5°S where new major elemental, trace elemental, and Nd, Sr, and O isotope data were acquired. From the western United States magmatic fluxes and compositions were compiled from the literature, as were characteristics of Jurassic IOCG occurrences in the central Mojave Desert, California. Geologic framework analysis at 1:250K scale and new 1:5K scale mapping of the hydrothermal features associated with Jurassic IOCG occurrences were conducted in the central Mojave Desert, California. Results from northern Chile reveal that the Coastal Batholith formed in a dominantly extensional setting, had episodic magma fluxes that were dominantly mafic (dioritic-quartz dioritic) during peak output, and has uniformly depleted mantle-like Nd and Sr isotopes regardless of magma composition. Published compilations from coeval arcs of North America indicate that they display the opposite relationships to Chile between tectonic setting, magmatic fluxes, and magmatic compositions. Results from mapping in the southern Palen Mountains, California, and synthesis of composite exposures across the central Mojave Desert, California demonstrates that IOCG systems in this region are vertically zoned and genetically related Jurassic intrusions ranging from diorite/gabbro to granite in composition. The mineralized occurrences have intermediate depth (1–4 km), cores of magnetite±hematite mineralization with sparse Fe(-Cu) sulfides, and zone upward to acid-altered tops and downward to Fe-depleted, metal-poor, Na±Ca-altered roots. These patterns resemble those observed in IOCG systems throughout the Cordillera of the Americas.

Le cancer des ovaires est le septième cancer le plus commun chez les femmes dont le taux de survie à 5 ans est en deçà de 45% et dont le taux de détection des premiers stades de développement est inférieur à 20%. Avant d’arriver à un traitement, de nombreux défis restent à relever.Le développement de nouveaux traitements ciblant spécifiquement les cellules cancéreuses en réduisant les effets secondaires liés au traitement est nécessaire. Pour cela, le Sélénium a été étudié et a démontré à forte doses d’être efficace contre les cellules cancéreuses in vitro. De plus, les essais cliniques ont montré que l’utilisation de doses tolérables de sélénium (<90µg/jour) n’avait pas d’effet thérapeutique contre le cancer. Le développement de nouvelles formes de sélénium afin d’augmenter les doses administrées est donc nécessaire afin d’atteindre l’effet thérapeutique souhaité. Au cours de cette thèse j’ai mesuré l’effet de formes agrégées de sélénium appelées nanoparticules et démontré leur capacité à inhiber la croissance de cellules cancéreuses ovariennes. Dans les lignées cellulaires cancéreuses ovariennes SKOV-3 et OVCAR-3, le traitement aux SeNPs a déclenché la mort cellulaire. La mesure des propriétés nanomécaniques de ces deux lignées cellulaires après traitement a démontré un effet différent des SeNPs en fonction du type cellulaire. Les cellules OVCAR-3 ont vu diminuer leur rugosité de surface ainsi que leur rigidité cellulaire alors que les cellules SKOV-3 ont augmenté leur rigidité et leur rugosité, ces deux caractéristiques étant liées à une diminution de leur potentiel métastatique. De plus, le traitement aux SeNPs a augmenté de manière considérable la méthylation de trois lysines de l’histone 3 H3K4, H3K27 et H3K9. Cette méthylation a pu être bloquée par l’utilisation d’inhibiteurs de méthyltransférases spécifiques de ces marqueurs. L’étude du profil d’expression des deux lignées cellulaires après traitement a démontré le fait que le sélénium induit des modifications d’expression des méthyltransférases nous permettant de suggérer un mécanisme d’action du sélénium. De plus les SeNPs ont démontré leur impact sur l’expression marqueurs cancéreux comme l’activation de la réparation de l’ADN, la réponse aux espèces réactives de l’oxygène, la réorganisation de la matrice extracellulaire. L’effet des SeNPs semble dépendant du type cellulaire cependant leur bonne tolérabilité in vivo offre de bonnes perspectives d’utilisation en tant que traitement du cancer.Enfin, dans la continuité de récentes études sur le cancer du sein le cancer colorectal s’intéressant à la mesure des isotopes du cuivre (rapport 63Cu/65Cu) et démontrant leur potentiel dans la détection du développement de ces cancers, j’ai pu mesurer le contenu isotopique de biopsies et de prélèvements sanguins issus de patientes atteintes de cancers ovariens. J’ai pu mesurer une diminution significative du rapport des isotopes du cuivre dans le sérum des patientes cancéreuses en comparaison avec des témoins sains démontrant l’efficacité de détection des cancers par la mesure des isotopes du cuivre dans le sang
Ovarian cancer is the seventh most common cancer in women with five-year survival rates of less than 45%, and only 20% of cases are detected at early stages of the disease. Major challenges still exist to treat this lethal disease.The development of new drugs that target better cancer cells and reduce side effects is highly needed. Selenium at high doses has been shown to act as a cytotoxic agent, with potential applications in cancer treatment. However, clinical trials have failed to show any chemotherapeutic value of selenium at safe and tolerated doses (<90 g/day). To enable the successful exploitation of selenium for cancer treatment, I evaluated inorganic selenium nanoparticles (SeNP), and found them effective in inhibiting ovarian cancer cell growth. In both SKOV-3 and OVCAR-3 ovarian cancer cell lines SeNP treatment resulted in significant cytotoxicity. The two cell types displayed contrasting nanomechanical responses to SeNPs, with decreased surface roughness and membrane stiffness characteristic of OVCAR-3 cell responses. In SKOV-3, cell membrane surface roughness and stiffness increased, both are properties associated with decreased metastatic potential. Very excitingly I made the novel discovery that SeNPs dramatically increase histone methylation at three histone marks, namely H3K4, H3K27 and H3K9. This effect was partially blocked by pharmacological agents that blocked histone methyltransferase (HMT) function. Gene expression profiling of SeNP treated cells demonstrated that Se caused changes in the expression of HMTs suggesting one mechanism for its ability to alter histone methylation. Further interrogation of RNA seq data showed the SeNPs impact on the expression of genes linked to hallmarks of cancer such as DNA repair activation, ROS response, extracellular matrix organization. The beneficial effects of SeNPs on ovarian cancer cell death appear to be cell type dependent, and due to their low in vivo toxicity, offer an exciting opportunity for future cancer treatment.Finally, following on from recent studies in breast and colorectal cancer patients revealing that measurement of circulating copper isotopes (63Cu/65Cu ratio) can be related to cancer development I investigated this in clinical ovarian cancer samples (blood and tissue). A significant decrease in copper isotopic ratios in the serum of cancer donors was observed demonstrating the potential effectiveness of 63Cu/65Cu for the blood-based detection of ovarian cancer

The Mt. Milligan deposit is a tilted (~45°) Cu-Au alkalic porphyry located 155 km northwest of Prince George, B.C., Canada. It is the youngest of the BC alkalic porphyry deposits, all of which formed between 210 to 180 Ma in an extensive belt of K-enriched rocks related to the accretion of the Quesnellia-Stikinia superterrane to ancestral North America. Mt. Milligan has a measured and indicated resource of 205.9 million tonnes at 0.60 g/t Au and 0.25% Cu containing 3.7 million oz. gold, and 1.12 billion lb. copper. Shoshonitic volcanic and volcaniclastic andesites host mineralization. These have been intruded by a composite monzonitic stock (MBX stock), and associated sill (Rainbow Dike). Early disseminated chalcopyrite-magnetite and accessory quartz veins are associated with K-feldspar alteration in the MBX stock. A halo of biotite alteration with less extensive magnetite replaces host rocks within a ~150 m zone surrounding the stock, while K-feldpsar alteration extends along the Rainbow Dike and permeable epiclastic horizons. Peripheral albite-actinolite-epidote assemblages surround the K-silicate zone. Albite-actinolite occurs at depth, and epidote dominates laterally. Copper and Au grade are maximal where the albite-actinolite assemblage overprints biotite alteration. Gold grade is moderate in association with epidote, whereas Cu is depleted. The post-mineral Rainbow Fault separates the core Cu-rich zone from a downthrown Au-rich zone. A similar zonation of metals occurs in the hanging-wall (66 zone), where a Cu-bearing, potassically-altered trachytic horizon transitions to a funnel-shaped zone of pyrite-dolomite-sericite-chlorite alteration with elevated gold. Sulfide S-isotope compositions range from -4.79 δ34S in the central Cu-Au orebody to near-zero values at the system periphery, typical of alkalic porphyries. Sulfur isotope contours reflect the magmatic-hydrothermal fluid evolution, and indicate late-stage ingress of peripheral fluids into the Cu-Au zone. Carbonate C- and O-isotope compositions corroborate the magmatic fluid path from the Cu-Au rich zone to Au-rich zone with decreasing depth. Strontium isotopic compositions of peripheral alteration minerals indicate a laterally increasing meteoric fluid component. Changes in major- and trace element composition of epidote and pyrite across the deposit are also systematic. These provide additional vectors to ore, and confirm the kinematics of the Rainbow Fault.

Nuclear reactions induced by neutrons, protons and alpha particles on copper isotopes are being studied in an effort to understand the nucleosynthesis of elements in stars, specifically, the p-process. The p-process occurs toward the end of a star's life and produces those elements which have a high proton to neutron ratio, which are heavier than iron. Little is known about the nature of the p-process-inside stars. Isotopes of copper are studied since they are close in mass number to iron, which has the highest nuclear binding energy. Nuclear cross sections will be calculated for copper, as well as S-factors, which are important from an astrophysical point of view. These values are needed to calculate reaction rates which are the main ingredients for understanding nucleosynthesis.
Department of Physics and Astronomy

Caractérisé par le déclin progressif et irréversible des fonctions biologiques vitales, le vieillissement est un processus biologique complexe qui s’accompagne souvent par l’apparition de maladies neurodégénératives. D’ici 2050, plus de 1.5 milliards de personnes dans le monde seront définies comme vieillissantes. L'amélioration de la qualité de vie des personnes âgées constitue donc un enjeu majeur pour notre société. Encore mal connue, la dégradation progressive du métallome est associée au vieillissement et à l’apparition de maladies neurodégénératives et en est probablement l’une des causes. L’objectif de cette étude est de mieux caractériser l'évolution du métallome chez deux modèles animaux au cours du temps i.e. la souris et le vers ainsi que chez l’humain atteint de sclérose latérale amyotrophique (SLA). Pour ce faire, nous avons analysé une vingtaine d'éléments traces et majeurs ainsi que les compositions isotopiques du cuivre (δ65Cu) et du zinc (δ66Zn) d’organes de souris, de différentes souches de nématodes, et de liquides céphalo-rachidiens (LCRs) humains. L’analyse des organes de souris montre que d’importants dérèglements chimiques et isotopiques se développent dans l’organisme avec l’âge, chaque organe ayant sa propre signature élémentaire et isotopique. On observe par exemple une hausse de la concentration en Cu dans le cerveau associée à une diminution de δ65Cu dans le foie au cours du vieillissement. Grâce à l’analyse métabolomique et à l’utilisation de mélanges isotopiques, nous montrons que ces variations pourraient s’expliquer par des dysfonctionnements physiologiques et métaboliques majeurs comme des dérèglements de flux hépatique et/ou la dégradation de la barrière hémato-encéphalique avec l’âge. Cela suggère que l’analyse temporelle du métallome pourrait être un marqueur de l’âge biologique. L’analyse de nématodes a révélée qu’un animal génétiquement modifié pour vivre plus longtemps se distinguait des autres nématodes à plus courte durée de vie par une baisse de sa concentration et de sa composition isotopique en Cu dès son plus jeune âge. Le suivi temporel de ces biomarqueurs devrait permettre de détecter un vieillissement précoce. Finalement, l’analyse de LCRs de patients atteints de SLA, une maladie neurodégénérative sévère pour laquelle il n’existe aucun biomarqueur ni traitement, montre qu’une personne atteinte de SLA se distingue de sujets sains et de patients touchés par la maladie d’Alzheimer par des compositions isotopiques en Cu plus positives. Cette spécificité, laissant entrevoir de nouvelles perspectives concernant l’identification de biomarqueurs spécifiques de la SLA, pourrait s'expliquer par la formation d’agrégats protéiques toxiques dans le cerveau
Characterized by the progressive and irreversible decline of vital biological functions, ageing is a complex biological process that often comes with neurodegenerative disorders. In 2050, more than 1.5 billion elderly are expected in the world. Improve the quality of life of these ageing people is therefore a major challenge for our society. Still poorly known, the progressive degradation of the metallome is asscociated with ageing and neurodegenerative diseases development and is probably one of their causes. The objective of this study is to better characterize the metallome evolution in two animal models over time i.e. the mouse and the worm as well as in human affected by amyotrophic lateral sclerosis (ALS). To do this, we analyzed twenty trace and major elements as well as the isotopic compositions of copper (δ65Cu) and zinc (δ66Zn) of mouse organs, different strains of nematodes, and human cerebrospinal fluid (CSFs).The analysis of mouse organs shows that important chemical and isotopic changes develop in the body over time, each organ having its own elemental and isotopic signature. For example, we observe an increase of the Cu concentration in the brain associated with a decrease of the δ65Cu in the liver over time. Based on the analysis of metabolomic parameters and the use of isotopic mixings, we show that these variations may be explained by major physiological and metabolic dysfunctions, such as the deregulation of hepatic fluxes and/or the degradation of the blood-brain barrier with age. This suggests that the temporal analysis of the metallome could be used as a potential marker of the biological age.The analysis of nematodes revealed that long-lived animals differ from short-lived nematodes by an early-age decrease in their Cu isotopic composition and Cu concentration. The temporal monitoring of these biomarkers could therefore be used to detect premature ageing conditions.Finally, the analysis of CSFs of patients with amyotrophic lateral sclerosis (ALS), a severe neurodegenerative disease for which there is currently no reliable biomarker or treatment, shows that ALS patients have a higher δ65Cu compared to healthy subjects and Alzheimer’s disease patients. This feature, offering new perspectives to identify ALS-specific biomarkers, may be explained by the formation of toxic protein aggregates in the brain

Depuis les années soixante-dix, l'outil isotopique, d'abord développé en géochimie, s'est généralisé en anthropologie. Il est en effet susceptible d'apporter des informations métaboliques complémentaires à l'étude ostéologique, notamment sur la mobilité et l'alimentation des populations passées. Cependant, sur la trentaine d'éléments présente dans le corps humain, seuls six d'entre eux sont classiquement étudiés dans les ossements. Dès lors, les isotopes stables d'autres éléments représentent une source d'informations inexploitée. Ils pourraient effectivement contribuer aux questions cruciales que sont la diagnose sexuelle, l'estimation de la fécondité ou encore l'évaluation de l'âge au décès.Le but de ce travail de thèse est de comprendre l'origine de la variabilité isotopique du cuivre, du zinc et du fer dans le corps humain, et ainsi, d'évaluer l'apport potentiel de ces métaux de transition à l'anthropologie. Pour cela, les éléments ont été séparés par chromatographie sur résine échangeuse d'ions. Puis les rapports isotopiques ont été mesurés par spectrométrie de masse à source plasma et à multicollection (MC-ICP-MS).L'analyse du δ56Fe et δ65Cu de phalanges de squelettes du XVII-XVIIIèmes siècles provenant de Saint-Laurent de Grenoble a permis de mettre en évidence une différence isotopique entre hommes et femmes, reflet de celle observée dans le sang. Cette dissemblance isotopique est discutée à partir d'un modèle mathématique s'appuyant sur nos analyses du foie et de l'émail dentaire. Celui-ci nous a amenés à mettre en cause le rôle de la sollicitation hépatique dans la composition isotopique du sang plutôt que celui de l'absorption intestinale. L'étude du δ56Fe, δ65Cu et δ66Zn dans le sang d'une population française et d'une population yakoute a également contribué à dégager trois autres facteurs significatifs de variabilité isotopique : la ménopause, l'âge et le stress thermique.Nos résultats sont donc en faveur du développement de l'analyse des isotopes stables du Fe, Cu et Zn des restes humains en tant que vecteur potentiel d'informations sur leur âge au décès, âge à la ménopause, sexe et adaptation métabolique au froid.

The Cassenha Hill copper-gold prospect is situated in the Catabola area, Huambo Province, southwestern Angola. Geologically, the prospect is part of the Angolan Central Eburnean Zone (CEZ) and consists of Paleoproterozoic metasedimentary rock sequences which have been intruded by Eburnean granitoids at ± 2.1 Ga. The prospect itself comprises an area of 180 Km2 and has been intermittently explored since 2005 by Rift Valley Resources (RVR) and its associates. The Cassenha Hill prospect is characterized by the occurrence of partially altered and highly oxidized metasedimentary rocks (meta-mudstone, meta-siltstone, carbonate-rich rock, meta-sandstone, breccia, and quartzite), and altered isolated granitoids. This study represents the first detailed study of the prospect and aims to shed light on the characteristics of the various rock types (i.e., host and barren rocks), their source/provenance, styles of alteration, and the origin and/or type of the fluid responsible for the mineralization. Techniques applied include borehole core logging, petrography, whole-rock geochemistry (XRF and ICP-MS), and stable isotope geochemistry on samples collected on the surface and from exploration boreholes drilled as part of RVR exploration program. Overall, the petrographic and geochemical studies undertaken in the rocks of the Cassenha Hill prospect indicate the following: (1) The rocks are moderately to strongly fractured; (2) The rocks have experienced weak to moderate chemical weathering; (3) The rocks are compositionally immature and originated from felsic provenance; (4) The rocks are sulfur-poor, and lacking in sulfide minerals (5) The rocks are enriched in LREE and LILE elements and depleted in HREE and HFSE elements; (6) The mineralization is associated with chloritization alteration and predominantly occurs within and/or at the edges of quartz/chlorite-rich veins/fractures and is not restricted to any rock type. Two ore stages could be identified, namely, hypogene ore (stage I) consisting of pyrite ± chalcopyrite ± other copper sulfides, and supergene ore (stage II) consisting of malachite ± azurite ± chrysocolla, which represents the prevalent mineralization at the prospect. The δ 18O value of quartz veins range from +12.81 to +13.53‰, while the δD of chlorite minerals range from -51 to -45‰. Therefore, assuming fluid-rock interaction took place at ≈ 350oC, due to the presence of quartz, the fluid had δ 18OH20 values of about +8‰, which are typical of magmatic waters. On the other hand, at a temperature of ≈ 350oC, and with the difference between chlorite and water being -33.5‰, such fluids would have had δDH20 values of about -20‰ (δ 18OH20= -4‰), which are typical of meteoric waters. Although the various mineral phases have yielded different isotopic signatures, this study suggests that water is ultimately of meteoric origin but exchanged with hydrogen-poor magmatic rock, thus maintaining the meteoric signature. The continuous influx of meteoric waters within the fracture system led to the development of copper oxides such as malachite, azurite and chrysocolla, which possibly originated from the insitu oxidation of the hypogene sulfides. This signature, together with other field, petrographic and geochemical observations allows one to, tentatively, suggest that the Cassenha Hill prospect represents an extension of a polymetallic vein-type of porphyry Cu deposit that has been subjected to supergene processes at the weathering profile.

The ‘giant’ Tambogrande volcanogenic massive sulphide (VMS) deposits within the Cretaceous Lancones basin of northwestern Perú are some of the largest Cu-Zn-Au-Ag-bearing massive sulphide deposits known. Limited research has been done on these deposits, hence the ore forming setting in which they developed and the key criteria that permitted such anomalous accumulation of base-metal sulphides are not understood. Based on field relationships in the host volcanic rocks and U-Pb geochronology, the deposits formed during the early stages of arc development in the latest Early Cretaceous and were related to an extensional and arc-rift phase (~105-100 Ma, phase 1). During this time, bimodal, primitive basalt-dominant volcanic rocks were erupted in a relatively deep marginal basin. Phase 1 rhyolite is tholeiitic, M-type, and considered to have formed from relatively high temperature, small batch magmas. The high heat flow and extensional setting extant during the initial stages of arc development were essential components for forming a VMS hydrothermal system. The subsequent phase 2 (~99-91 Ma) volcanic sequence comprises more evolved mafic rocks and similar, but more depleted, felsic rocks erupted in a relatively shallow marine setting. Phase 2 is interpreted to represent late-stage arc volcanism during a waning extensional regime and marked the transition to contractional tectonism. The Tambogrande deposits are particularly unusual amongst the ‘giant’ class of VMS deposits in that deposition largely occurred as seafloor mound-type and not by replacement of existing strata. Paleomorphology of the local depositional setting was defined by seafloor depressions controlled by syn-volcanic faults and rhyolitic volcanism. The depressions were the main controls on distribution and geometry of the deposits and, due to inherently confined hydrothermal venting, enhanced the efficiency of sulphide deposition. Geochemical and radiogenic isotope data indicate that the rhyolites in the VMS deposits were high temperature partial melts of the juvenile arc crust that had inherited the isotopic signatures of continental crust. Moreover, Pb isotope data suggest the metal budget was sourced almost wholly from mafic volcanic strata. Therefore, unlike the implications of many conventional models, the felsic volcanic rocks at Tambogrande are interpreted to have only played a passive role in VMS formation.

Dans l'ouest de l'Europe, une grande importance est accordée à la composante sol dans l'élaboration des vins. La nutrition minérale est la principale voie par laquelle le sol peut avoir une influence sur la vigne et par conséquent sur le vin qui en est issu. Dès lors, ce travail de thèse appréhende la question plus large des transferts élémentaires entre le sol et la plante à travers de l'utilisation d'outils géochimiques en milieu viticole. Une combinaison de techniques impliquant des indicateurs classiques tels que les rapports élémentaires ou des bilans de masses ainsi que des traceurs plus innovants comme les rapports isotopiques du Cu et la résonance paramagnétique électronique (RPE) est utilisée. Dans un premier temps, l'influence du sol sur la composition élémentaire du vin a été étudiée dans plus que 200 vins provenant d'Allemagne, d'Espagne, de France, et d'Italie. A cette échelle, le type de sol (classé comme calcaire ou non-calcaire) et les conditions météorologiques apparaissent comme des critères discriminants. Par la suite, deux parcelles viticoles de Soave (Italie) aux sols contrastés ont été étudiées afin de d´déterminer l'influence du type du sol sur les vignes. Même si les sols présentent des propriétés pédologiques différentes, une pédogénèse complexe a induit des propriétés géochimiques similaires. Dans les vignes, les traceurs élémentaires et biochimiques montrent que la variabilité inter-annuelle et inter-individuelle est plus grande que la différence liée au sol lui-même. Néanmoins, il est possible de déterminer quel est le sol considéré par l'étude des rapports isotopiques du Sr. Parmi tous les nutriments et éléments toxiques généralement étudiés pour leur mobilité dans les sols, le cuivre a été suivi dans la dernière partie de cette thèse, essentiellement du fait de son épandage toujours massif comme fongicide en viticulture. En effet, les pesticides cupriques comme la bouillie bordelaise sont utilisés depuis environ 150 ans en viticulture. Le Cu s'accumule d`es lors dans les sols et les conséquences ´ecotoxicologiques en font un sujet de plus en plus sensible. Parmi les pesticides analysés dans notre étude, les rapports isotopiques du Cu varient autant entre les différents fongicides que dans les sols étudiés dans la littérature, rendant ainsi impossible l'utilisation de ces isotopes comme traceurs d'origine du Cu dans les sols. [...]
In western Europe, soil is of primordial importance for wine making. Soil qualities are often discussed and an influence on wine flavor is frequently inferred. However, evidence for a role of soil chemistry on wine composition and taste is scarce, but mineral nutrition of grapevine plants is one possible way of influence. This thesis approaches the complex question of elemental cycling between soil and plant through the use of geochemical tracers in vineyard environments. A combination of traditional tracers such as elemental ratios and mass balances as well as innovative tools such as Cu isotope analysis and electron paramagnetic resonance (EPR) are used on different observation scales. The influence of soil type on wine elemental composition was investigated using over 200 wine samples from France, Germany, Italy and Spain. Results of chemical analysis were then statistically linked to environmental conditions. At this scale, elemental contents of wine vary depending on soil type (calcareous or not), meteorological conditions, and wine making practice. To determine which soil properties can influence the chemical composition of grapevine plants, two vineyard plots on contrasted soils in Soave (Italy) were examined. Soil forming mechanisms were studied along two catenas and subsequently linked to elemental composition of grapevine plants and biochemical markers of plant health. Even though soil morphology was different, complex soil forming processes led to similar geochemical properties of soils. Differences in plant chemical compositions between soil types are small compared to inter-individual and inter-annual variability. However the use of Sr isotopic ratios allows the determination of the pedological origin of plants. In a next step, the fate of Cu pesticides in vineyard soils was studied. Cu-based pesticides have been used for almost 150 years in European vineyards and Cu accumulates in soils, so that the fate of Cu and its ecotoxicological implications are of growing importance. Therefore, Cu mobility in vineyard soils and transfer to grapevine plants were investigated using stable Cu-isotope ratios and EPR-measurements. Isotope ratios of Cu-based fungicides vary largely between products, covering Cu isotope ratios in soils reported in literature and thus making source tracing impossible. However, Cu isotope ratios are useful for tracing biogeochemical mechanisms of Cu transport in soils. The vertical transport of Cu in different soil types was investigated in the Soave vineyard using a combination of mass balance calculations, kinetic extractions and δ65Cu-isotope ratios. Results suggest that Cu can be transported to depth even in carbonated environments. Besides it is shown that heavy organic-bound Cu is lost from carbonated soil columns likely caused by dissolution of Cu carbonates by organic matter. [...]

Ce travail de thèse avait pour objectif de développer de nouveaux chélatants du cuivre(II) de type bispidine pour des applications en Tomographie à Emission de Positrons. Le 64Cu est un radioisotope métallique dont les propriétés sont intéressantes pour la TEP. Les bispidines sont des chélatants dont la structure est préorganisée et rigide. Cette propriété confère au bispidine de bonnes propriétés de coordination vis-à-vis des métaux de transition, en particulier le cuivre(II). Ce travail présente le développement d’un ligand de type bispidine possédant un groupement phosphonate ainsi que le développement de bispidines permettant la synthèse de nouvelles familles de chélatants pour le cuivre(II). La bispidine phosphonatée a ensuite fait l’objet d’une étude physico-chimique par différentes techniques, révélant ainsi qu’elle possède les caractéristiques requises pour des applications en TEP. Le radiomarquage en présence de 64Cu a été étudié pour une sélection de plusieurs chélatants et montre le fort potentiel des ligands de type bispidine pour la complexation du 64Cu. Enfin, diverses stratégies de fonctionnalisation ont été étudiées pour l’obtention d’un chélatant bifonctionnel basé sur la bispidine phosphonatée. Ces stratégies démontrent la possibilité d’obtenir deux ligands bifonctionnels. De surcroît, deux plateformes bifonctionnelles peuvent faire l’objet de point de départ pour le développement de nouvelles familles de bispidines bifonctionnelles
This PhD work aimed at developing new bispidine-based copper(II) chelating agents for applications in Positron Emission Tomography (PET). On one hand, 64Cu is a metallic radioisotope which possesses interesting properties for PET imaging and on the other hand, bispidines have a pre-organized and rigid structure. This property makes them good chelating agents for numerous transition metals, particularly copper(II). This work presents the development of a new bispidine-based ligand having a phosphonate pendant arm as well as the development of bispidines allowing the synthesis of new chelating agents for copper(II). The physico-chemical properties of the phosphonated bispidine were thoroughly studied by different techniques, showing that it would be adequat for PET applications. Radiolabeling experiments were also done in the presence of 64Cu for various bispidines and show the high potential of bispidine ligands for the complexation of 64Cu. Finally, several functionalization strategies were studied in order to get bifunctional chelates based on the phosphonated bispidines. This study proved the possibility to develop two bifunctional bispidines based on the phosphonated one and also it allowed us to develop two bifunctional bispidines as synthon for the synthesis of new families of bifunctional bispidines

Orientadores: Lena Virginia Soares Monteiro, Roberto Perez Xavier
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Geociências
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Resumo: Localizados na porção norte da Província Mineral de Carajás, a uma distância de cerca de 8 km do depósito de óxido de ferro-cobre-ouro de Sossego, estão os depósitos de cobre Alvo Bacaba e Alvo Castanha. Esses depósitos encontram-se ao longo de uma zona de cizalhamento regional de cerca de 60 km de extensão, no limite entre o Supergrupo Itacaúnas e seu embasamento representados principalmente pelos migmatitos do complexo Xingu. O Alvo Bacaba é hospedado pelo granito Serra Dourada e pelo tonalito Bacaba, enquanto o Alvo Castanha é Ambos os depósitos exibem amplas zonas de alteração hidrotermal que compreendem quase que respectivamente a albitização, a escapolitização, a formação de óxidos de ferro, a alteração sódico-cálcica, a alteração potássica, a formação de turmalina, a sericitização, a cloritização, a epidotização e a carbonatização, embora estes depósitos mostrem diferenças, como a alteração sódico-cálcica que apesar de ser bem desenvolvida no Alvo Castanha, é quase inexistente no Alvo Bacaba, onde apenas ocorre como alteração nos gabros. Também o Alvo Bacaba possui uma associação de minerais distintas, composta por calcopirita±pirita±bornita, enquanto o Alvo Castanha exibe a associação calcopirita±pirrotita±pirita. Informações sobre evolução paragenética e dados de isótopos estáveis indicam que os depósitos Alvo Bacaba e Alvo Castanha evoluíram durante progressivo resfriamento. Entretanto, esta redução com relação à evolução paragenética foi maior no Alvo Bacaba do que no Alvo Castanha, e a fugacidade de oxigênio foi mantida alta no Alvo Bacaba. A temperatura de deposição do minério estimada para o Alvo Bacaba pode ter ocorrido entre 220 °C e 410 °C, enquanto no Alvo Castanha esta teria ocorrido entre 350 °C e 420 °C. A evolução isotópica do Alvo Bacaba é similar àquela caracterizada para o depósito de Sossego, com uma redução acentuada da temperatura acompanhada por um decréscimo no valor de ?18O e acréscimo no valor de ?D e evidências de misturas de fluido juvenil e de fonte não magmática. Já para o Alvo Castanha, as composições isotópicas dos fluidos hidrotermais indicam a predominância de uma fonte magmática. Estas características e similaridades com aquelas de Sossego podem apontar para uma contribuição de águas magmáticas e oceânicas no sistema hidrotermal que originou todos estes depósitos
Abstract: The Alvo Bacaba and Alvo Castanha copper deposits are located at the northern part of the Carajás Mineral Province, at a distant radius of about 8 km from the Sossego iron oxide-copper-gold deposit. These deposits occur along a regional shear zone 60 km wide, in the limit between the Itacaiúnas Supergroup and its basement represented mainly by migmatites of the Xingu Complex. Both deposits exhibits widespread hydrothermal alteration zones comprising albitization, scapolitization, iron oxide formation, sodic-calcic alteration, potassic alteration, tourmaline formation, sericitization, epidotization and carbonatization, although these two deposits show differences like sodic-calcic alteration, which is well developed in Alvo Castanha, but it is almost inexistant in Alvo Bacaba, being present only in its altered gabbros. Also the Alvo Bacaba shows ore minerals association essencialy composed by chalcopyrite±pyrite±bornite while the Alvo Castanha shows the association of chalcopyrite±pyrrhotite±pyrite. Paragenesis and stable isotope data indicate that the Alvo Bacaba and Alvo Castanha deposits have evolved with temperature decrease. However, the temperature drop in relation to the hydrothermal alteration succession was greater in Alvo Bacaba than the Alvo Castanha, and the oxygen fugacity was kept higher at Alvo Bacaba. The estimated temperature for ore deposition in the Alvo Bacaba was between 220 °C and 410 °C, while the Alvo Castanha it would have occurred between 350 °C and 420 °C. The isotopic evolution of the Alvo Bacaba is similar to that characterized for the Sossego deposit, with a steep temperature reduction accompanied by decrease of ?18O and increase of ?D values and fluid mixing evidences. In the Alvo Castanha, isotopic compositions of the hydrothermal fluids indicate predominance of magmatic sources. These characteristics and its similarities with those of the Sossego deposit could point to a contribution of magmatic and ocean waters in the hydrothermal system that originated all deposits
Mestrado
Geologia e Recursos Naturais
Mestre em Geociências

La péninsule d’Oman est une entité géo-culturelle qui s’organise autour des montagnes d’al-Hajjar, extrêmement riches en minerais de cuivre. Ce dernier a probablement été exploité dès la période Hafit (3000 - 2500 av.n.è.) et le métal produit deviendra une matière d’échange avec la Mésopotamie à la période Umm an-Nar (2500 - 1900 av.n.è.). À l’âge du Fer (1350 - 300 av.n.è.), ces échanges deviennent plus flous, mais la production de cuivre elle, ne diminue pas. Les sites de réduction et de travail du métal de la péninsule d’Oman sont extrêmement massifs et fonctionnent à l’aide d’une gestion et d’une organisation complexes. De plus, ce métal ne connaît pas de concurrence, le fer n’ayant été produit qu’à partir de la fin de l’âge du Fer et le bronze étant relativement peu représenté au sein du corpus métallique. Notre étude a tenté d’identifier les procédés mis en place par les métallurgistes grâce à une méthodologie croisant prospections archéo-métallurgiques et analyses physico-chimiques des vestiges de la production (scories, lingots et objets finis). Ces objets ont été retrouvés dans des contextes d’habitats, de caches ou d’ateliers métallurgiques, il s’agit principalement d’armes, de bracelets, de bols et de figurines de serpent, animal auquel les populations locales semblaient vouer un culte exclusif. Les analyses chimiques attestent une fabrication locale, à partir d’un minerai issu des montagnes d’al-Hajjar. Cependant, il apparaît que la pratique du recyclage d’objets contribue activement à l’approvisionnement des populations en cuivre. Le métal obtenu est chimiquement très mélangé et semble avoir été utilisé dans la fabrication de beaucoup d’objets, sans distinction de type ou d’usage. Malgré l’absence d’un système d’écriture connu, les populations de l’âge du Fer livrent des vestiges archéologiques qui attestent d’une organisation sociale complexe, au sein de laquelle le cuivre semble avoir joué un rôle important, en contribuant au maintien d’une identité locale forte
The Oman Peninsula is a geo-cultural entity organized around the al-Hajjar mountains, which are extremely rich in copper ores. This metal was probably exploited since the Hafit period (3000 - 2500 BC) and the metal produced will become a trading material with Mesopotamia during the Umm an-Nar period (2500 - 1900 BC). During the Iron Age (1350 - 300 B.C.), these exchanges became more blurred, but copper production did not decrease. The reduction and metalworking sites of the Oman Peninsula are extremely massive and operate with complex management and organization. Moreover, this metal is not competitive, as iron was only produced at the end of the Iron Age and bronze is relatively under-represented in the metallic corpus. Our study attempted to identify the processes implemented by metallurgists using a methodology that combines archaeometallurgical prospecting and physico-chemical analysis of production remains (slag, ingots and finished objects). These objects were found in various contexts : settlements, hiding places or metallurgical workshops. They are mainly weapons, bracelets, bowls and snake figurines, an animal to which the local populations seemed to devote an exclusive cult. Chemical analysis attest a local production, using ore from the al-Hajjar mountains. However, it appears that the practice of recycling objects actively contributes to the supply of copper to the population. The resulting metal is chemically highly mixed and appears to have been used in the manufacture of many objects, regardless of type or use. Despite the absence of a writing system, archaeological remains of the Iron Age populations attest to a complex social organization, in which copper seems to have played an important role, contributing to the development of a strong local identity

A ureia (UR) é atualmente o fertilizante nitrogenado mais utilizado na agricultura brasileira. No entanto, quando aplicada na superfície do solo está sujeita a perdas de nitrogênio (N) por volatilização de NH3. Uma das formas de minimizar as perdas de N-NH3 é o tratamento do fertilizante com inibidores de urease. A associação desses compostos com substâncias húmicas (SH), no tratamento da UR poderia aumentar a eficiência de uso dos nutrientes pelas plantas. O objetivo desse trabalho foi avaliar a eficiência de inibidores de urease, associados ou não com SH no revestimento da UR como fonte de N em cobertura para o milho. O experimento foi conduzido em casa de vegetação durante 62 dias em delineamento experimental de blocos ao acaso, com três repetições, no esquema fatorial completo, com UR recoberta três inibidores de urease (0,40% B + 0,15% Cu; 0,64% B; NBPT) e um tratamento adicional sem inibidor (Ausente), três doses de SH (0, 0,6, e 1,2%) e um controle. Os tratamentos com N constaram da aplicação de fonte única do nutriente [CO(15NH2)2] aplicada em faixa e em superfície na dose de 180 mg kg-1 de N no estádio fisiológico V4 das plantas de milho. As plantas foram amostradas nos estádios V8 e VT do milho, respectivamente, aos 52 e 62 dias após a semeadura, quando foram avaliados: biometria de parte aérea, área foliar, biomassa seca de raízes e da parte aérea, caracterização morfológica do sistema radicular, e a eficiência de uso do N-fertilizante (EUN) pelo método do balanço isotópico (15N). Também se quantificou as perdas de N por volatilização de NH3 por meio de coletores semi-estáticos com espuma embebida em H3PO4- para avaliação comparativa entre tratamentos. Embora a concentração mais elevada de ácido bórico na UR (0,64% B) tenha reduzido mais as perdas de NH3 por volatilização em comparação ao 0,40 % B + 0,15 % Cu, isso não resultou em maior eficiência de uso do N-fertilizante pelo milho em VT, que ocorreu somente em V8. Em ambos os estádios, o NBPT apresentou-se como melhor inibidor de urease na ausência de SH. A aplicação de SH não aumentou a EUN pelo milho em V8 ou VT quando associados com 0,40% B + 0,15% Cu, 0,64% B, ou mesmo na UR convencional. Entretanto, quando associado com o NBPT, ocorreu aumento das perdas de NH3 por volatilização e redução na EUN em VT, o que pode ter ocorrido devido ao elevado pH das SH (8,5-9) e ao seu baixo poder tampão. A aplicação da UR convencional ou revestida com inibidores de urease não aumentou a taxa de crescimento ou biomassa seca de raízes e parte aérea do milho em nenhum dos períodos avaliados quando comparado ao controle. Da mesma forma, não foram observadas diferenças expressivas entre tratamentos na caracterização morfológica do sistema radicular em V8 ou VT. A ausência de diferença entre tratamentos pode ser explicada pelo curto período de tempo entre a adubação de cobertura e as avaliações das plantas, à aplicação superficial das fontes recobertas com SH e ao método de irrigação adotado, que impediu que as SH entrassem totalmente em contato com as raízes da planta. Além disso, é possível, também, que a dose de SH empregada tenha sido muito baixa para ser efetiva.
Urea (UR) is the most widely applied nitrogen (N) fertilizer in Brazilian agriculture. However, UR is more prone to ammonia (NH3) volatilization losses than other N sources when surface-applied. One alternative to improve nitrogen use efficiency (NUE) of surface-applied UR is through application of urease inhibitors as coating materials of UR. The association of these composts with humic substances (HS) as UR coating materials may also improve nutrient recovery by plants. The aim of this study was to evaluate the efficiency of urease inhibitors, associated or not with HS, as coating materials of UR as new top-dress N sources for maize. A greenhouse pot trial was carried out over 62 days with maize (Zea mays L.), in a completely randomized block design, with three replicates in a full factorial design, with UR coated with three urease inhibitors (0,40% B + 0,15% Cu; 0,64% B; NBPT) and one additional treatment without inhibitor, three doses of HS (0, 0.6, and 1.2%), and one control treatment. All treatments imposed had CO(15NH2)2 as N source, application rate of 180 mg kg-1of N, and side-dressing application at the V4 maize growth stage. Maize plants were assessed at V8 and VT growth stages, at 52 and 62 days after sowing, respectively, when it was evaluated: above and below-ground plant dry matter weight; leaf area; root morphological traits (length, surface area, and volume); and fertilizer use efficiency by the 15N balance method. In addition, semi-open static collectors with foam discs previously soaked in H3PO4- were used to quantify comparatively the NH3 volatilized from all treatments. Although the addition of a higher dose of boric acid on UR (0,64% B) promoted lower ammonia losses by volatilization in comparison to 0,40 % B + 0,15 % Cu, it did not result in higher NUE by maize in VT, which occurred at V8. In both growth stages, NBPT presented the best performance as urease inhibitor in the absence of HS. The application of HS did not increase NUE by maize in V8 and VT when associated with 0,40% B + 0,15% Cu, 0,64% B or even conventional UR. However, when added in conjunction with NBPT, it increased ammonia volatilization and reduced NUE in VT which may have occurred due to the high pH of the HS (8.5-9) and low buffering capacity. Moreover, the application of conventional UR or UR treated with HS and urease inhibitors did not increase maize growth rate or shoot/root dry matter weight in comparison to the control treatment at both growth stages. Likewise, there was no major significant differences between treatments on root morphological traits (length, surface area, and volume) at both growth stages assessed. The lack of sizable outcome differences between treatments could be explained by the application of a single N dose, the short period of time between the side-dressing application and assessment of maize plants, and to the surface-application of the HS and method of irrigation which prevented HS to have full contact with maize roots. Furthermore, HS application rate may have been too low to be effective.

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Many isotope proxies have been applied to study the prosperous iron oxide copper gold (IOCG) province in the eastern Gawler Craton (E.G.C) and Au mineralised region of the cental Gawler Craton (C.G.C), in Southern Australia. Yet, copper isotope proxies- an indicator for low temperature fluid flow and sulfide mineralisation- have yet to be applied to the region. In this study, purification techniques using automatic column chromatography were demonstrated during separation of Cu from matrix elements. Cu isotopes – 65Cu & 63Cu – were used to understand the extent of mantle input and mantle metasomatism, potentially responsible for the Cu in IOCG mineralisation. Eleven samples were gathered. Three mafic enclaves and four intrusives from the Central Gawler Gold Province and four intrusives from the eastern Gawler IOCG province. Separation using automatic column chromatography proved challenging, with matrix elements abundant throughout the purified fractions (Co, Ti, Fe, Mg, Na), due to poor separation. Ti proved to a major interference during isotopic analysis using a Multicollector-ICP-MS, positively offsetting values. E.C.G samples showed the most positively fractionated δ65Cu values (+0.69 ± 0.024‰ to +1.422 ± 0.077‰). Enclaves from the C.G.C showed the most negatively fractionated δ65Cu values (-0.053 ± 0.023‰ to -0.897 ± 0.006‰), while intrusives from this region showed more positive δ65Cu values (+0.084±0.23‰ to +0.397±0.011‰). All samples showed a lack of hydrothermal alteration. Magmatic sulphide-containing E.G.C samples had the most positive δ65Cu values; which cannot be explained by current understanding of Cu isotope fractionation during sulfide saturation. This trend may instead be attributed to a heterogeneous sub-continental lithospheric mantle (SCLM) source. In contrast the negative δ65Cu values of mafic enclaves is possibly caused by assimilation of S-type granitic crust and/or possibly due to a heterogeneous SCLM source.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2019

Boyongan is a blind copper-gold porphyry deposit that was discovered by Anglo American Exploration (Philippines), Inc. in August 2000. It is located in Surigao del Norte, Philippines. Current inferred mineral resources for Boyongan are estimated at 219 million tonnes of combined oxide and sulfide material with an average grade of 0.51% copper and 0.74 grams of gold per tonne. Most of the high-grade mineral resource is within the oxide (supergene zone). Deep oxidation at Boyongan has developed a thick supergene enrichment profile (up to 600 meters) which has a complex supergene mineralogy, consisting of chalcocite, digenite, pseudo-covellite, native copper, cuprite, malachite, pseudo-malachite, azurite, chrysocolla, pseudo-chrysocolla, and pseudo-neotocite. Fine gold (<100μm) has been observed in goethite, chalcocite, chrysocolla, and malachite. Supergene mineralisation is associated with iron oxides (goethite with minor hematite) and clays (kaolinite, halloysite, illite and montmorillonite). Oxidation and the development of supergene minerals has been controlled mainly by fracturing and the availability of hypogene sulfides. The low pyrite content of hypogene mineralisation at Boyongan allowed supergene mineralisation to develop in-situ from near-neutral pH groundwaters. The initial stages of supergene mineralisation involved the replacement of hypogene sulfides such as chalcopyrite and bornite by chalcocite, digenite and pseudo-covellite. In some places, chalcocite replaced pyrite. Goethite formed during the weathering of pyrite, chalcopyrite, bornite and chalcocite. Copper that was released into solution precipitated as native copper, which has replaced chalcocite locally. Native copper was then oxidised to form cuprite, and also acicular and euhedral crystals of chalcotricite. Some cuprite may have precipitated directly from solution, and also where chalcocite reacted with oxygenated groundwaters. The final stages of supergene copper mineralisation at Boyongan produced copper carbonate (malachite, pseudo-malachite, azurite and pseudo-neotocite) and a copper silicate overprint (chrysocolla and pseudo-chrysocolla) onto earlier-formed copper oxides and sulfides. Copper generally has a more dispersed or erratic distribution than gold. Gold is restricted spatially to the early mineral intrusions. Copper grades in the cuprite-dominated zone in the west generally decrease with depth toward zones of patchy native copper. The copper carbonate (malachite-azurite)-dominated blanket above the cuprite zone contains both high grade copper and gold (>1% and >2 g/t, respectively). Chalcocite zones that have partially replaced hypogene copper sulfides have higher grades (>0.5% Cu and >1g/t Au) compared to zones of chalcocite replacing pyrite (<0.5% Cu and <0.5g/t Au). Chrysocolla and/or pseudo-chrysocolla is confined to zones that contain high copper and gold grades (>0.5% and >1 g/t, respectively). Isotopic compositions of malachite and azurite from Boyongan are consistent with deposition from ambient temperature (15°C to 20°C) meteoric water. These low temperatures are consistent with Boyongan being a low-sulfide porphyry system. Higher pyrite contents would probably have led to greater degrees of sulfide oxidation as well as higher groundwater temperatures. `δ^13C` values of malachite are consistent with an organic carbon (soil?) source suggesting that malachite may have formed when Boyongan was uplifted and exposed. `δ^13C` values of azurite are much higher, and could be derived from seawater, or by remobilisation of an inorganic carbon from carbonate wallrocks, or by sulfide oxidation by supergene-related bacteria above the water table.

The Olympic Dam Cu-U-Au-Ag deposit is a syngenetic orebody hosted by the Olympic Dam Breccia Complex, a high level, hematite-rich hydrothermal breccia system. The breccia complex occurs entirely within, and clearly post-dates, the Roxby Downs Granite. _Cu-Fe sulphide distribution within the deposit is zoned from pyrite-rich assemblages at depth, upwards to chalcopyrite-rich ores, ultimately to bornite-chalcocite ores. Mlnor proportions of paragenetically early magnetite are widely distributed. Felsic and mafic/ultramafic dykes are broadly coeval with ore deposition. The Roxby Downs Granite has an age of 1588 ± 4 Ma. Prior to this study the age of the breccia complex was unclear. SHRIMP U-Pb isotopic data for zircons from three igneous rock units constrain the minimum age for the bulk of the mineralisation. Twb autobrecciated felsic dykes that intrude hematite-rich sedimetitary rocks and·hydrothermal breccias have ages of 1592.± 8 Ma and 1584 ±- 20 Ma respectively. An ashfall tuff horizon from within a diatrerne that cross-cuts hematite-quartz breccias contains zircons with an age of 1597 ± 8 Ma. These three minimum age constraints are within error of the age of the host granite, meaning that the breccia complex has an age of -1590 Ma. This age determination allows confident correlation of ore deposition with a major regional magmatic episode, the Gawler Range/ Hiltaba-volcano-plutonic event. Pb isotopic measurements of hydrated U-Th-Y-REE~rich hydrothermal zircon-xenotime overgrowths on magmatic zircons yielded evidence of complex Pb mobility histories, and provided no strong evidence regarding the age of the deposit. SHRIMP analyses of Olympic Dam pitchblende indicate that U and Pb mobility has reset isotopic systematics heterogeneously, even on a microscopic scale. This open system behaviour is also apparent from the data of earlier workers. An earlier U-Pb concordia upper intercept "age" of 1400 Ma for Olympic Dam pitchblende, calculated by regression analysis of averaged isotopic analyses, should therefore be regarded with caution. Sm-Nd isotopic data indicate that the different hematite-sulphide assemblages share an initial ENd signature of -2.5. This suggests that these ore types are cogenetic at 1590 Ma. This signature also indicates that ore fluids received contributions of Nd from crustal rocks such as the host granite (£Nd -5) and from rocks or magmas derived from the mantle at 1590 Ma. In contrast, the volumetrically minor magnetite-rich assemblages have the same initial Nd signature as the host granite, suggesting that they are possibly cogenetic. The hematitic ores and breccia~ yield a fourteen point Sm-Nd isochron age of 1572 ± 99 Ma consistent with the age constraints provided by zircon geochronology. The least altered mafic/ultramafic dykes within the deposit have an initial isotopic signature of eNd +4 and are therefore a plausible source of the primitive Nd component in the hematitic rocks. With progressive alteration, these dykes have become depleted in several of the elements that are enriched in the Olympic bam ores and breccias, particularly Cu, Cr, Ni, V, Mn, Nb and Y. The trace element and Nd isotopic relationships strongly implicate the mafic/ultramafic dykes, or their plutonic or extrusive equivalents, as metal sources. Interpreted primary enrichments in incompatible elements suggest a strongly alkaline affinity for the mafic/ultraniafic rocks. Rb-Sr isotopic systematics of the Olympic Dam breccias and mafic/ultramafic dykes show evidence of open system behaviour after ore deposition. No firm conclusions regarding ore genesis are drawn from these data. In view of the data presented, plausible hypotheses of ore genesis include: a) fluid mixing involving a hypogene, granite-related fluid, and a saline meteoric fluid transporting metals of economic interest that have been leached from the Gawler Range volcanic pile, and b) the sequential activity of a granite-related fluid that produced magn-tite-rich mineralisation, and a fluid derived by late-stage exsolution of magmatic volatiles from an alkaline mafic or ultramafic pluton .

I. A compilation of 362 cooling ages, including 52 newly reported in this study, from nine thermochronometric systems, ⁴⁰K/³⁹Ar amphibole, ⁴⁰K/³⁹Ar white mica, ⁸⁷Rb/⁸⁶Sr white mica, ⁴⁰K/³⁹Ar biotite, ⁸⁷Rb/⁸⁶Sr biotite, zircon and apatite fission track, zircon and apatite (U-Th)/He, indicate that the base of the Austroalpine allochthonous ‘orogenic lid’ was not in full thermal equilibrium with its Penninic substrate until at least the middle Oligocene, approximately 29-28 Ma, to allowably as late as the early Miocene, ca. 18 Ma. There is about a factor-of-five difference in cooling rates between the hanging wall (ca. 4°C/m.y.) and footwall (ca. 20°C/m.y.) during this period. In addition, there are demonstrably higher metamorphic grades, including blueschist- and eclogite-facies, in the Pennine footwall compared to lower greenschist-facies in the Austroalpine hanging wall. Together these two facts demonstrate that hot, high-pressure Penninic nappes were forced upward against the cold, low-pressure overriding Austroalpine plate in a very short time window of approximately 7-10 m.y. between the time of peak metamorphism during the Eocene and the time of thermal equilibration with the overriding plate during the Oligo-Miocene. The most likely mechanism to produce such a cold-on-hot juxtaposition is a normal fault, and therefore, we conclude that an important period of nappe emplacement in the Central Swiss Alps occurred concurrently with orogen-perpendicular normal fault motion at the base of the Austroalpine allochthon persisting well into the Oligocene and possibly into the early Miocene, post-dating the 32-30 Ma age of the Bergell intrusion.

Mesoscopic structural measurements made at the top and bottom of the Pennine zone in eastern Switzerland indicate multiple, spatially heterogeneous directions of movement. At the top, in the Oberhalbstein Valley, movement directions vary from dominantly top-east to top-south-southeast a very minor top-north component within Pennine rocks of the Martegnas shear zone and no preferred movement direction within the Austroalpine hanging wall. Near Piz Toissa, a minimum of two kilometers of nearby structural section in the Err and Platta nappes have been faulted out. At the bottom of the Pennine zone in Val Lumnezia and the Chur Rhein Valley at Trimmis, we observe top-northwest, top-north, and top-northeast movements. In Val Lumnezia, the Sub-Penninic Scopi zone (Gotthard cover rocks) shows movement in a top-northwest direction; the superjacent Peidener imbricate fault zone, a relatively thin (ca. 50 to 100 m thick) structural zone consisting of Scopi zone lithologies, shows movement in a northeasterly direction; above that, the basal Penninic Bündnerschiefer shows no dominant movement direction. To the east, in the Chur Rhine Valley, movement is well defined as exclusively top-north. Therefore, movement directions in the lower Bündnerschiefer are broadly top-north but heterogeneous in direction along strike between Val Lumnezia and Chur Rhein Valley, and, as first suggested by Weh and Frotizheim (2001), it may be erroneous to regard the basal Pennine thrust as a simple through-going structure. In Val Lumnezia, the Scopi-Peidener-Pennine nappes resemble a “jelly sandwich” in which the thick Pennine mass utilized the Peidener zone to move in an oblique sinistral-normal slip sense past the southeast-dipping allochthonous Scopi zone and its east-dipping Gotthard “massif” substrate. If the Peidener zone continues northeastward beneath alluvial cover of the Chur Rhein Valley, it may serve as a late, NE-directed shear zone that separates the Pennine nappes from European units. If so, it would explain the apparent truncation and progressive omission of allochthonous elements of European affinity along the zone from southwest to northeast beneath alluvium of the Chur Rhein Valley. We therefore infer that the direct juxtaposition of Penninic units to the east with the Helvetic autochthon to the west at the latitude of Trimmis records an episode of top-northeast, orogen-parallel strike-slip and extensional movement.

Zircon (U-Th)/He (ZHe) cooling ages from the Oberhalbstein Valley indicate that the Austroalpine-Pennine contact was still active at ca. 27 Ma, and that the Martegnas shear zone was active, in part, between ca. 27 and 24 Ma. It is likely that the Piz Toissa klippe formed around this time during the late Oligocene. The pattern of much younger ZHe ages at the bottom of the Pennine zone is independent of any nappe boundaries, including the Peidener imbricate fault zone, but is consistent with the rise of the Aar massif during the Miocene. Tectonic movements, as recorded by the mesostructure in the Austroalpine, Penninic, and Sub-Penninic domains, and local ZHe cooling ages generally support the conclusion drawn strictly from cooling ages that the Pennine zone was emplaced en masse as a coherent ‘piston’ or ‘mega-pip’ during Oligocene to early Miocene time (approximately 29 to 18 Ma), well after juxtaposition of Apulia with cratonic Europe (continent-continent collision) and during the development of Alpine topography and the peripheral basins (viz. Molasse and Lombardi). Additional top-north movement and late uplift and flexure of the nappe stack, along with the Aar massif, occurred primarily in middle to upper Miocene time, following the post-collisional structural interposition of the Pennine zone between Europe and Apulia.

II. Nine carbonate phases at Kennecott, Alaska were measured for their clumped isotope (∆₄₇) equilibration temperatures. The total range for carbonate temperatures spans 38-164°C. Premineral phases are relatively cool (43-71°C); synmineral phases are relatively warm (89-157°C); late postmineral phases are the most cool (38-59°C) but overlap some premineral phases. Zebra dolomite precipitated in the range 130-163°C. Dedolomite, a hallmark alteration feature of the mineralizing fluids, falls into a narrow range of 98-109°C, consistent with the stability field for the low-temperature chalcocite polymorph. Except for one sample, none of the synmineral calcites crystallized within the stability field of djurleite, a volumetrically significant component of the main-stage ore, which suggests that intergrown djurleite may have been a somewhat later recrystallization product of chalcocite rather than a coeval phase.

Calculated compositions for δ¹⁸O_water vary from -4.2 to +11.0‰. The most depleted water precipitated hydrothermal baroque dolomite, whereas the most enriched water was associated with recrystallized limestone wallrock on the periphery of the orebody. Waters that precipitated calcite+copper vary from -1.1 to +9.3‰.

Intriguingly, rhythmic layering in zebra dolomite can be resolved in ∆₄₇ space, and preliminary data indicate that the coarser-grained baroque dolomite bands precipitated at temperatures 5-10°C cooler than the surrounding, finer-grained dolomite wall rock bands.

The calculated values of δ¹⁸O_water support a genetic model that invokes redox changes associated with fluid mixing as the likely mechanism responsible for copper deposition. In this model a sulfidic, basinal fluid having δ¹⁸O similar to seawater mixes with a cuprous fluid having heavier δ¹⁸O (5 to 8‰) which was derived from the Nikolai Greenstone during prehnite-pumpellyite-facies metamorphism.