Literatura académica sobre el tema "Isotopes Li et Nd"

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Artículos de revistas sobre el tema "Isotopes Li et Nd"

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Bryant, Colleen J., Bruce W. Chappell, Victoria C. Bennett y Malcolm T. McCulloch. "Lithium isotopic compositions of the New England Batholith: correlations with inferred source rock compositions". Earth and Environmental Science Transactions of the Royal Society of Edinburgh 95, n.º 1-2 (marzo de 2004): 199–214. http://dx.doi.org/10.1017/s0263593300001012.

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ABSTRACTA strong correlation exists between the Li isotopic compositions of CarboniferousTriassic granites from the New England Batholith, and the previously inferred involvement of sedimentary and mantle/infracrustal source components. Isotopically (Nd and Sr) juvenile, low-K, Cordilleran I-type granites of the Clarence River supersuite have δ7 Li= +2·2 to +8‰ similar to those of arc magmas, the inferred source of these granites (Bryant et al. 1997). Isotopic variability within this supersuite probably arises from heterogeneity within primary mantle-derived magmas, combined with subsequent modifications through interactions with crustal materials. Oxidised, high-K granites of the Moonbi Supersuite have more homogenous and slightly lighter Li isotopic compositions (δ7 Li= +1·9 to +4·2‰). The observed range of values lies within the range of arc magmas, and is consistent with partial melting of arc shoshonites within the crust (cf. Chappell 1978) or the involvement of high-K mantle-derived magmas (cf. Shaw & Flood 1981; Landenberger & Collins 1998). S-type granites of the Bundarra (δ7 Li= −0·1 to +2·1‰; average= +1˙3‰; n=6) and Hillgrove supersuites (δ7 Li= +0·4 to +1·7‰; average= +0·8‰) define a narrow range of isotopic compositions which are, overall, lower than those observed in NEB I-type granites or generally observed in primary arc magmas. Their isotopic compositions are equivalent to those typically observed in shales (primarily δ7 Li= −3·2 to +2·0‰; Moriguti & Nakamura 1998; Teng et al. 2004). No difference is evident in the isotopic compositions of the two S-type supersuites despite inferred differences in the degree of weathering experienced by the sedimentary protolith, or differences in mineralogy of the granites. Granites of the Uralla Supersuite, which have been have formed from mixtures of local meta-igneous and meta-sedimentary components, span a broad range of values (δ7 Li= −1·3 to +3·9‰) which overlap with both the sediment-poor New England Batholith I-type intrusions of the Clarence River and Moonbi supersuites, and the S-type granites of the Bundarra and Hillgrove supersuites. Lower δ7 Li values primarily occur in lower-K plutons from the northern portion of the Uralla Supersuite.Overall, anatexis and magma differentiation do not appear to contribute to significant fractionation of Li isotopes relative to the inferred source components. However, subtly lower δ7 Li values, evident in the three leucogranites analysed herein, imply that subtle Li isotopic fractionation may occur in association with the exsolution of an aqueous fluid. Like most isotopic systems, the Li isotopic composition of rocks is not a definitive guide to source rock compositions, but given the results herein, the present authors suggest that it may play a very useful role in understanding crustal processes.
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2

Huong, Tran Thi y Nguyen Hoang. "Petrology, geochemistry, and Sr, Nd isotopes of mantle xenolith in Nghia Dan alkaline basalt (West Nghe An): implications for lithospheric mantle characteristics beneath the region". VIETNAM JOURNAL OF EARTH SCIENCES 40, n.º 3 (4 de junio de 2018): 207–27. http://dx.doi.org/10.15625/0866-7187/40/3/12614.

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Study of petrological and geochemical characteristics of mantle peridotite xenoliths in Pliocene alkaline basalt in Nghia Dan (West Nghe An) was carried out. Rock-forming clinopyroxenes, the major trace element containers, were separated from the xenoliths to analyze for major, trace element and Sr-Nd isotopic compositions. The data were interpreted for source geochemical characteristics and geodynamic processes of the lithospheric mantle beneath the region. The peridotite xenoliths being mostly spinel-lherzolites in composition, are residual entities having been produced following partial melting events of ultramafic rocks in the asthenosphere. They are depleted in trace element abundance and Sr-Nd isotopic composition. Some are even more depleted as compared to mid-ocean ridge mantle xenoliths. Modelled calculation based on trace element abundances and their corresponding solid/liquid distribution coefficients showed that the Nghia Dan mantle xenoliths may be produced of melting degrees from 8 to 12%. Applying various methods for two-pyroxene temperature- pressure estimates, the Nghia Dan mantle xenoliths show ranges of crystallization temperature and pressure, respectively, of 1010-1044°C and 13-14.2 kbar, roughly about 43km. A geotherm constructed for the mantle xenoliths showed a higher geothermal gradient as compared to that of in the western Highlands (Vietnam) and a conductive model, implying a thermal perturbation under the region. The calculated Sm-Nd model ages for the clinopyroxenes yielded 127 and 122 Ma. 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Gudelius, Dominik, Sonja Aulbach, Hans-Michael Seitz y Roberto Braga. "Crustal fluids cause strong Lu-Hf fractionation and Hf-Nd-Li isotopic provinciality in the mantle of continental subduction zones". Geology 50, n.º 2 (2 de noviembre de 2021): 163–68. http://dx.doi.org/10.1130/g49317.1.

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Abstract Metasomatized mantle wedge peridotites exhumed within high-pressure terranes of continental collision zones provide unique insights into crust-mantle interaction and attendant mass transfer, which are critical to our understanding of terrestrial element cycles. Such peridotites occur in high-grade gneisses of the Ulten Zone in the European Alps and record metasomatism by crustal fluids at 330 Ma and high-pressure conditions (2.0 GPa, 850 °C) that caused a transition from coarse-grained, garnet-bearing to fine-grained, amphibole-rich rocks. We explored the effects of crustal fluids on canonically robust Lu-Hf peridotite isotope signatures in comparison with fluid-sensitive trace elements and Nd-Li isotopes. Notably, we found that a Lu-Hf pseudo-isochron is created by a decrease in bulk-rock 176Lu/177Hf from coarse- to fine-grained peridotite that is demonstrably caused by heavy rare earth element (HREE) loss during fluid-assisted, garnet-consuming, amphibole-forming reactions accompanied by enrichment in fluid-mobile elements and the addition of unradiogenic Nd. Despite close spatial relationships, some peridotite lenses record more intense fluid activity that causes complete garnet breakdown and high field strength element (HFSE) addition along with the addition of crust-derived unradiogenic Hf, as well as distinct chromatographic light REE (LREE) fractionation. We suggest that the observed geochemical and isotopic provinciality between peridotite lenses reflects different positions relative to the crustal fluid source at depth. This interpretation is supported by Li isotopes: inferred proximal peridotites show light δ7Li due to strong kinetic Li isotope fractionation (−4.7–2.0‰) that accompanies Li enrichment, whereas distal peridotites show Li contents and δ7Li similar to those of the depleted mantle (1.0–7.2‰). Thus, Earth's mantle can acquire significant Hf-Nd-Li-isotopic heterogeneity during locally variable ingress of crustal fluids in continental subduction zones.
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Patra, Arghya y Paul V. Braun. "(Industrial Electrochemistry and Electrochemical Engineering Division H. H. Dow Memorial Student Achievement Award) Electrochemically Grown Highly Textured Thick Ceramic Oxide Films for Energy Storage: A New Manufacturing Paradigm for Cathode Materials". ECS Meeting Abstracts MA2022-02, n.º 26 (9 de octubre de 2022): 1025. http://dx.doi.org/10.1149/ma2022-02261025mtgabs.

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Electrochemical synthesis of materials has contributed to significant breakthroughs in materials processing by replacing high temperature, cost and energy intensive pyrometallurgical processes. Noteworthy examples include aluminum extraction by Hall–Heroult process, electrowinning of copper, titanium extraction through the Kroll process, electrolytic production of steel, and electrochemical synthesis of cement. Increasing the energy and power density of alkali ion intercalated transition metal oxide cathodes which power electric cars and portable electronics, has been a growing topic of global techno-economic interest. Our work demonstrates a direct electrodeposition of thick ternary ceramic oxide films as an alternate scalable manufacturing technique for fabrication of binder-and-additive free cathode materials for secondary battery. Employing an intermediate temperature (200-400°C) molten hydroxide-based electrodeposition method, a general electrochemical growth strategy for multiple Li and Na ion cathode chemistries is demonstrated for the first time including NaCoO2, NaMnO2, LiCoO2, Li2MnO3, LiMnO2, LiMn2O4, (A. Patra, P.V. Braun et. al, PNAS, 2021) in a thick (> 50 µm) thick film form factor. In-plane and through-plane texture can be electrochemically architectured in LiCoO2 and NaCoO2 films across multiple textures: <003>||ND (Li/Na ion blocking sites parallel to the normal direction), <101>||ND, <104>||ND, <110>||ND (fast lithium ion conducting sites parallel to the normal direction). An accurate control of crystallization dynamics leads to highly anisotropic, grain boundary engineered structure with low tortuosity and fastest electron and Li ion conducting pathways (<110>||ND) oriented normal to the current collector. The highly textured (<110>||ND), dense (>95%) electroplated cathodes can perform even at ultrahigh thickness of ~ 200 µm (areal capacity of ~13.6 mAh/cm2) in comparison to 40-60 µm for conventional slurry cast cathodes (areal capacity of ~3-4 mAh/cm2 with a porosity of ~10-20%), a fivefold increase in areal capacity and volumetric energy density (A. Patra, P.V. Braun et. al, to be submitted). In order to enable a high voltage (> 4.5 V vs. Li) cathode design, a functionally graded architecture is also demonstrated with a core capable of providing high-capacity and rate capability (LCO <110>||ND); and multiple capping layers (LCO <003>||ND and Li2MnO3) to suppress harmful side reactions occurring at voltages beyond the normal operation range (beyond 4.2 V vs. Li). Our work paves the way towards an electrosynthesis platform for functional oxides with the ability to generate micron scale ordering with controllable in-and-through-plane orientation in thick ceramic oxide films important for electrochemical energy storage.
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Kakiuchi, Masahisa. "Fractionation of Hydrogen Isotopes in Aqueous Lithium Chloride Solutions". Zeitschrift für Naturforschung A 43, n.º 5 (1 de mayo de 1988): 449–53. http://dx.doi.org/10.1515/zna-1988-0509.

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The D/H ratio of hydrogen gas in equilibrium with water vapor over aqueous lithium chloride solutions was measured at 25 °C, using a hydrophobic platinum catalyst. Experimental details are described. The hydrogen isotope effect between the solution and pure water depends linearly on the LiCl concentration up to ca. 12 m, and at higher concentrations a marked deviation from linearity takes place, as was also observed for the oxygen isotope effect measured by Bopp et al. On the basis of these hydrogen and oxygen isotope effects it is concluded that H218O is enriched in the water molecules coordinated to Li+ ions and HD16O is enriched in the free water molecules of the solution. The observed deviation from linearity for concentrations higher than ca. 12m is interpreted in terms of structural changes in the hydration sphere of the Li+ ions.
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Yang, Chengfan, Nathalie Vigier, Shouye Yang, Marie Revel y Lei Bi. "Clay Li and Nd isotopes response to hydroclimate changes in the Changjiang (Yangtze) basin over the past 14,000 years". Earth and Planetary Science Letters 561 (mayo de 2021): 116793. http://dx.doi.org/10.1016/j.epsl.2021.116793.

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Kurbatov, Andrei V., Paul A. Mayewski, Jorgen P. Steffensen, Allen West, Douglas J. Kennett, James P. Kennett, Ted E. Bunch et al. "Discovery of a nanodiamond-rich layer in the Greenland ice sheet". Journal of Glaciology 56, n.º 199 (2010): 747–57. http://dx.doi.org/10.3189/002214310794457191.

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AbstractWe report the discovery in the Greenland ice sheet of a discrete layer of free nanodiamonds (NDs) in very high abundances, implying most likely either an unprecedented influx of extraterrestrial (ET) material or a cosmic impact event that occurred after the last glacial episode. From that layer, we extracted n-diamonds and hexagonal diamonds (lonsdaleite), an accepted ET impact indicator, at abundances of up to about 5×106 times background levels in adjacent younger and older ice. The NDs in the concentrated layer are rounded, suggesting they most likely formed during a cosmic impact through some process similar to carbon-vapor deposition or high-explosive detonation. This morphology has not been reported previously in cosmic material, but has been observed in terrestrial impact material. This is the first highly enriched, discrete layer of NDs observed in glacial ice anywhere, and its presence indicates that ice caps are important archives of ET events of varying magnitudes. Using a preliminary ice chronology based on oxygen isotopes and dust stratigraphy, the ND-rich layer appears to be coeval with ND abundance peaks reported at numerous North American sites in a sedimentary layer, the Younger Dryas boundary layer (YDB), dating to 12.9 ± 0.1 ka. However, more investigation is needed to confirm this association.
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Chen, Changjian, Shuan-Hong Zhang, Yue Zhao, Jun-Ling Pei, Jian-Min Liu y Liang Gao. "Genetic relations between enclaves and their host granitoids from Doumer Island, northern Antarctic Peninsula: Evidence from mineral chemistry, Sr–Nd and Li isotopes". Lithos 398-399 (octubre de 2021): 106235. http://dx.doi.org/10.1016/j.lithos.2021.106235.

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Horita, Juske. "Discussion on the studies of position-specific carbon isotopes of propane by Li et al. (2018), Zhang et al. (2022) and Shuai et al. (2023)". Organic Geochemistry 192 (junio de 2024): 104795. http://dx.doi.org/10.1016/j.orggeochem.2024.104795.

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HOU, Jianglong, Biao JIANG y Hongzhang DAI. "Geochemistry, Monazite U–Pb Dating, and Li–Nd Isotopes of the Madi Rare Metal Granite in the Northeastern Part of the North China Craton". Acta Geologica Sinica - English Edition 93, n.º 4 (agosto de 2019): 901–11. http://dx.doi.org/10.1111/1755-6724.13798.

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Tesis sobre el tema "Isotopes Li et Nd"

1

Yang, Chengfan. "Li isotope study of Yangtze River sediments : new constraints on climate, weathering and carbon cycle relationships". Electronic Thesis or Diss., Sorbonne université, 2020. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2020SORUS433.pdf.

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Au cours de ce travail, j’ai réalisé une série d'études dans le bassin du Changjiang (Yangtze), afin de mieux comprendre l'influence de ces effets.Tout d'abord, l'exploitation du barrage des Trois Gorges (TGD) a modifié la composition géochimique des sédiments en aval. Depuis 2003, les sédiments venant des hauts bassins ont été en grande partie retenus en amont, tandis que les sédiments précédemment déposés dans le bassin moyen-inférieur ont été progressivement remis en suspension. Ces processus expliquent l’évolution géochimique des sédiments exportés vers la mer de Chine. En deuxième partie, une étude systématique démontre que les compositions isotopiques en lithium des phases dissoutes et particulaires se comportent de façon conservative dans la zone de mélange de l'estuaire du Changjiang. Cependant, les phases échangeables ne représentent qu'une faible quantité de Li, ce qui explique son impact négligeable dans cette zone. Troisièmement, Cette étude confirme que dans les grands bassins versants, l'altération chimique peut réagir rapidement à de grandes amplitudes climatiques. Ceci est particulièrement bien illustré, dans la carotte CM97, par la période du Younger Dryas. Depuis 2 000 ans, les δ7Li des argiles s’accentuent clairement par rapport à la période précédente, à cause de l'érosion des sols de plaines induite par l'homme. En résumé, ces résultats apportent de nouveaux éclairages sur l'interprétation des proxys et sur la réponse de l'altération chimique aux variations climatiques, ce qui est essentiel pour mieux quantifier l’impact du l’altération continentale sur les climats passés et futurs de notre planète
In order to better understand the weathering-climate feedback, a series of studies was carried out in the Changjiang (Yangtze) Basin. First, the operation of the Three Gorges Dam (TGD) changed downstream sediment geochemical compositions. Before 2003, large amounts of upstream-derived sediments deposited and experienced further weathering in the mid-lower basin. Since 2003, strong riverbed sediment resuspension changed the roles of the mid-lower reaches from important sinks to major sources of sediments delivered to the sea. As a consequence, an intensified weathering intensity of downstream sediment was observed.Second, dissolved δ7Li exhibit a conservative behavior in the Changjiang Estuary. During the process of SPM transported offshore, weathering product flocculated and deposited, while primary minerals resuspended. The combined effect resulted in the UCC-like SPM δ7Li values. There is a Li isotope fractionation between the dissolved load and exchangeable phase. However, this process shows negligible impact on δ7Li of dissolved load and particulates. Third, weathering response to climate is complex in large river basins. During the Younger Dryas, the positive excursion of clay δ7Li is consistent with enhanced incongruent weathering, in response to temperature cooling. The minor variation of clay δ7Li at 11 – 2 ka likely indicate stable weathering and mile climate variation. Over the last 2 kyr, the fluctuation of clay δ7Li is mostly caused by intensification of human activities. In summary, this thesis sheds new lights on the weathering-climate feedback over geologic past, and provides perspectives on how human activities affect natural processes
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2

Simien, Frédéric. "Croissance crustale et contraintes paléogéographiques apportées par les isotopes du Nd dans les sédiments". Paris, Institut de physique du globe, 1998. http://www.theses.fr/1998GLOB0005.

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Il n'existe pas de consensus pour savoir si la masse continentale a été extraite du manteau très tôt dans l'Histoire de la Terre ou bien si elle a été différenciée au cours du temps. Les études en Sm-Nd apportent des contraintes à ce problème car l'isotope père et l'isotope fils sont presque exclusivement fractionnés lors d'un épisode de différenciation crustale. Il est donc possible de dater depuis quand les matériaux font partie de la croûte. L'application de ce couple aux shales permet une approche à grande échelle car ils représentent une moyenne de la croûte continentale. Les évolutions des compositions isotopiques en Nd des séries paléozoïques en Europe de l'ouest et dans l'est du Canada indiquent qu'il n'y a pas eu de grand apports de matériaux juvéniles dans la masse sédimentaire au cours du Paléozoïque, même durant les orogenèses. Les informations apportées par cette méthode peuvent contraindre les reconstructions paléogéographiques. En accord avec les données stratigraphiques et paléontologiques, nous proposons qu'il faille reconsidérer les modèles d'évolution géodynamique dans lesquels un océan Sud Armorcain séparait la Bretagne de l'Espagne au cours du Paléozoïque. Les données canadiennes nous permettent de proposer un modèle d'évolution pour les zones exotiques des Appalaches. Nous pensons que la zone Avalon se situait à proximité de l'Amérique du Sud à l'aube du Paléozoïque, puis qu'elle a été accolée au continent nord Américain vers l'Ordovicien moyen (450 Ma). Pour la zone Méguma, nous pensons qu'elle devrait être rattachée à l'Afrique de l'ouest au Protérozoïque supérieur puis qu'elle est entrée en collision avecle continent Nord américain au Carbonifère (300 Ma). Dans la dernière partie, la compilation des données isotopiques en Sm-Nd dans les sédiments détritiques à grain fin permet d'avoir une idée de l'évolution de la croûte à l'échelle globale depuis presque 4 Ga. Malheureusement, pour pouvoir déterminer la courbe de croissance crustale, il nous faudrait connaître le volume de sédiments injectés dans le manteau au cours du temps et la taille du réservoir de type manteau appauvri dans les temps très anciens.
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3

Lahd, Geagea Majdi. "Caractérisation chimique et isotopique des aérosols organiques/inorganiques et détermination de l'impact de la pollution atmosphérique sur l'environnement urbain". Université Louis Pasteur (Strasbourg) (1971-2008), 2007. http://www.theses.fr/2007STR1GE14.

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Des écorces d'arbres et des aérosols ont été analysés pour déterminer la pollution par les métaux dans l'environnement urbain en utilisant les isotopes. Cette étude s'est focalisée sur trois aspects: 1) La composition isotopique du fond "naturel" dans la vallée du Rhin, les montagnes des Vosges et les Alpes Centrales (Suisse). 2) Les caractéristiques des terres rares et des isotopes du Pb, Sr, Nd des émissions d'une aciérie. 3) Le traçage des émissions industrielles dans un environnement urbain en utilisant les isotopes de Pb, Sr et Nd. Les poussières provenant des principales sources de pollution (incinérateurs, centrale thermique, aciérie) et les suies provenant des voitures et des bateaux ont été analysées. Les sources industrielles montrent des valeurs en εNd et en 87Sr/86Sr bien variables. Les aérosols collectés dans le centre urbain de Strasbourg montrent l'influence des différentes sources industrielles et naturelles
The aim of this study was to determine the heavy metal pollution in the urban environment of Strasbourg and Kehl with help of isotopes. This study focused on three aspects: 1) The « natural » background isotopic composition in the Rhine Valley, Vosges Mountains and the Central Swiss Alps. 2) The REE characteristics and Pb, Sr and Nd isotopic compositions of steel plant emissions. 3) Tracing of industrial aerosol sources in an urban environment using Pb, Sr and Nd isotopes. Filter dust of the principal pollutant sources (waste incinerators, thermal power plant, and steel plant) and soot of car and ship exhaust have been analyzed. The industrial sources have variable εNd values and 87Sr/86Sr ratios. PM10 collected in the urban centre of Strasbourg show the influence of different industrial and natural sources
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4

Munier, Thomas. "Évolution des conditions d’altération et des paléoclimats au cours de l'intervalle Albien-Santonien (113-83 Ma) : apports des minéraux argileux et de la géochimie". Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS156.pdf.

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L’intervalle Albien-Santonien (~113-83 Ma) est une période charnière dans l’histoire du Crétacé. Cet intervalle est caractérisé par un fort taux de production de croûte océanique, associée à la dislocation de la Pangée et par une activité importante des provinces magmatiques. Ces conditions engendrent une augmentation notable de la pCO2 (Arthur et al., 1985) et une hausse progressive des températures océaniques jusqu’au maximum thermique mi-Crétacé, enregistré à la limite Cénomanien/Turonien (~94 Ma). Ce maximum thermique est suivi, dès la fin du Turonien, par une baisse des températures et de la pCO2 (Linnert et al., 2014). La diminution du volcanisme, une production carbonatée accrue et un stockage de carbone organique important lors de l’événement océanique anoxique OAE 2 à la limite Cénomanien-Turonien participent à la diminution du CO2. Néanmoins l’altération des silicates peut également jouer un rôle dans cette baisse. L’étude de nouveaux forages, réalisés dans le cadre de la mission IODP 369 sur les marges sud et sud-ouest de l’Australie, couplés à d’anciens forages, obtenus lors des missions ODP 122 et 123 sur la marges nord-ouest, nous a permis d’étudier l’évolution des conditions d’altération durant cet intervalle aux moyennes et hautes latitudes dans une zone peu étudiée jusqu’à présent. Une étude détaillée, basée sur la minéralogie des argiles a été réalisée sur six sites dans le bassin de la Grande Baie (site U1512), le bassin Mentelle (sites U1513 et U1516), le bassin Carvarnon (sites 763 et 766) et la plaine abyssale d’Argo (site 765). Sur trois des sites étudiés (U1512, U1513 et 763), des observations au MEB et au MET et des analyses géochimiques (isotopie du Sr et du Nd, concentrations en éléments majeurs et traces) ont complété cette étude. Ces nouvelles données ont été comparées aux nombreux travaux déjà réalisés dans l’océan Atlantique et le domaine péri-téthysien. Au cours de l’intervalle Albien-Turonien, les assemblages de minéraux argileux sont caractérisés par une augmentation des proportions de smectites, observée sur l’ensemble des régions étudiées. Cette augmentation résulte de la combinaison de paramètres globaux et locaux. La stabilisation tectonique des marges africaines et nord-américaines réduit l’altération physique, ce qui entraine une diminution des proportions d’illites et de chlorites, et permet la mise en place de processus pédogénétiques favorisant la formation de smectites. L’altération préférentielle des roches volcaniques dès la fin du Cénomanien, mise en évidence par les mesures isotopiques du Sr et du Nd sur certains sites au large de l’Australie (U1513), entraine également une augmentation des smectites. Enfin, la hausse du niveau marin, enregistrée de l’Albien au Turonien inférieur et associé à un enrichissement en smectites, témoigne de l’influence de la sédimentation différentielle sur les cortèges argileux. L’intervalle Cénomanien/Turonien, caractérisé par une augmentation des kaolinites aux basses et moyennes latitudes de l’hémisphère nord, est marqué par des conditions plus hydrolysantes. Ces kaolinites sont abondantes dans les secteurs soumis aux contraintes tectoniques à la fin du Crétacé inférieur (Aptien-Albien). Ainsi, malgré un climat favorable à leurs formations, l’absence de ces kaolinites dans l’hémisphère sud caractérise l’influence de la topographie et la nécessité de bonnes conditions de drainage pour former ces argiles. L’intervalle Albien-Santonien est ainsi caractérisé par une intensification de l’altération chimique qui culmine au moment du maximum thermique mi-Crétacé. Cette hausse des conditions d’hydrolyse, découplée de l’altération physique, parait néanmoins insuffisante pour faire diminuer la pCO2 lors de ce maximum thermique. Il apparait alors que, malgré un climat favorable à l’hydrolyse, le haut niveau marin et l’aplanissement des masses continentales inhibent l’altération chimique des silicates qui ne tient plus son rôle de puits de CO2
The Albian-Santonian interval (~113-83 Ma) is a key period in Cretaceous history. This interval is characterised by a high seafloor spreading rate, related to the breakup of Pangea, and by a significant activity of large igneous provinces, which generate an increase in pCO2 (Arthur et al., 1985). These conditions lead to a progressive temperature increase until the mid-Cretaceous thermal maximum, recorded at the Cenomanian/Turonian boundary (~94 Ma). This latter is followed from the late Turonian by a decline in temperature and pCO2 (Linnert et al., 2014; Wang et al., 2014). A decrease of volcanic activity, an increase of carbonate production, and an enhanced organic carbon storage during the anoxic oceanic event OAE 2 (Cenomanian-Turonian boundary) are frequently cited to explain the pCO2 decline. However, silicate weathering can also be involved as a triggered mechanism for this decrease. The analyse of new boreholes, drilled during the IODP Leg 369 on the southern and southwestern margins of Australia, coupled with some old boreholes of the ODP Legs 122 and 123 on the northwestern margin, allowed us to investigate the evolution of weathering conditions during this interval at the middle and high latitudes in a poorly studied sector. A detailed work, based on clay mineralogy, has been done on six sites located in the Great Bay Basin (Site U1512), in the Mentelle Basin (sites U1513 & U1516), in the Carnarvon Basin (sites 763 & 766) and the Argo Abyssal Plain (Site 765), respectively. For 3 sites (U1512, U1513 and 763), these studies have been completed by SEM and TEM observations and geochemical analyses (Sr and Nd isotopic ratios and concentrations of major & trace elements). These new data have been compared to the several studies, already done in the Atlantic Ocean and in the peri-Tethyan domain. During the Albian-Turonian interval, the clay mineral assemblages are characterised by an increase in smectite proportions, observed over all the studied regions. This increase results from a combination of global and local parameters. The tectonic stabilisation of the African and North American margins reduces the physical weathering, which leads to a decrease in illite and chlorite proportions, and permits the implementation of pedogenetic processes, which favours the formation of smectites. The preferential weathering of volcanic rocks from the end of the Cenomanian, highlighted by Sr and Nd isotopic measurements on some sites of Australia (U1513) or Africa (959) margins, also results in a relative increase of smectites. Finally, the sea level rise, recorded from the Albian to the Lower Turonian and associated with an enrichment in smectites, highlights the influence of the differential settling process on clay assemblages. The Cenomanian-Turonian interval, characterised by an increase in the proportions of kaolinites at the low and middle latitudes of the Northern Hemisphere, is interpreted as marked by more hydrolysing conditions. These kaolinites are present only in sectors, where tectonic was active at the end of the Early Cretaceous (Aptian-Albian). Thus, despite a climate favourable to their formation, the absence of kaolinites in favour of smectites in the Southern Hemisphere characterizes the influence of topography and good drainage conditions to form these minerals. The Albian-Santonian interval is thus characterised by an increase in chemical weathering that was maximal at the mid-Cretaceous thermal maximum. Nevertheless, this increase in hydrolysing conditions, associated to the denudation of the continental landmasses, seems to be insufficient to cause the pCO2 decrease during this thermal maximum. It appears then, despite a climate favourable for hydrolysis, high sea level and flattening of the continental masses prevent the chemical weathering of silicates which cannot regulate pCO2
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5

Imbert, Stulc Anna. "Provenances géographiques des bois de la cathédrale de Notre-Dame de Paris. Compositions élémentaires et isotopiques en Sr et Nd : effet de la carbonisation, référentiels régionaux et applications". Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS594.pdf.

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La charpente de la cathédrale de Notre-Dame de Paris a failli disparaître lors de l’incendie qui l’a ravagé dans la journée du 15 avril 2019. Les vestiges des bois calcinés sont certes sans intérêt pour la reconstruction du bâtiment, mais ils recèlent en eux l’histoire d’un chantier qui s’est déroulé il y a plus de 800 ans. L’étude de ces archives archéologiques est ainsi une opportunité extraordinaire d’en apprendre plus sur son déroulement et sur la relation entre la société et la forêt au Moyen Âge Central (XIe-XIIIe siècles). Une des questions qui permettrait de mieux comprendre la gestion sylvicole et le commerce de bois à cette époque est celle de la provenance des bois. Cette thèse a pour but de préciser l’origine des bois utilisés pour la construction de la charpente avec l’aide des traceurs géochimiques, en particulier la composition multi-élémentaire et les rapports isotopiques du strontium (Sr) et néodyme (Nd) dans le bois. L’intérêt de ces traceurs est de discriminer des sites en fonction des contextes géologiques et pédologiques différents. Au cours de son développement, l’arbre absorbe des nutriments d’origine minérale qui sont en partie transférés dans les parois cellulaires du bois. Les teneurs en nutriments et leurs signatures isotopiques dans le bois reflètent celle des roches et sols sur lesquels l’arbre a poussé. Cette approche est appliquée ici pour la première fois sur le bois archéologique carbonisé. Avant de procéder à l’identification de l’origine des bois de Notre-Dame, 1) la conservation des traceurs géochimiques au cours de la carbonisation a été vérifiée expérimentalement, et 2) un référentiel des signatures multi-élémentaires et isotopiques dans des bois actuels a été réalisé à l’échelle du bassin versant de la Seine. L’exposition à la haute température n’a pas affecté la composition isotopique du Sr et Nd, mais a provoqué une volatilisation et la perte d’une partie des éléments. Des traceurs élémentaires ont été sélectionnés à partir des rapports d’éléments thermostables i.e., ceux dont la baisse de concentration a été négligeable (< 20 % à 800 °C). Le référentiel a été constitué à partir de 12 sites forestiers, chacun représentant un type de substrat spécifique, l’ensemble couvrant la diversité géologique et pédologique du bassin versant de la Seine. L’origine des bois actuels a pu être retracée avec une précision d’environ 80 % et la discrimination des sites s’est avérée fortement contrôlée par le rapport isotopique 87Sr/86Sr, et les rapports élémentaires Sr/Ca et Nd/Ca. Des bois archéologiques provenant de la charpente de Notre-Dame ont été caractérisés selon leur phase d’approvisionnement et leur signatures géochimiques ont été comparées entre elles, et avec celles des forêts référentielles. Les signatures géochimiques de la plupart des bois médiévaux sont caractéristiques des peuplements sur des sols limoneux profonds, en accord avec l'origine affirmée par des sources historiques, au sud-est de Paris
The wooden framework of the Notre-Dame de Paris Cathedral was almost destroyed by fire on April 15, 2019. Although the remains of the charred timbers are not of interest for the reconstruction, they conceal more than 800 years of the monument’s history. Their investigation thus constitutes an extraordinary opportunity to shed light on the construction techniques and relationships between society and forest resources during the Central Middle Ages (11th-13th centuries). A key point to better understand past forestry management and timber trade is the provenance of the timber woods. The aim of this work is to determine the geographical origin of the wood used to build the Notre-Dame's framework with the help of geochemical tracers, in particular the multi-elemental composition and isotope ratios of strontium (Sr) and neodymium (Nd). The strength of geochemical source tracing relies on the ability to discriminate sites based on their geological and soil contexts. During growth, trees absorb mineral-derived nutrients which are partially transferred to the wood cell walls. The abundance and isotopic signature of these mineral-derived nutrients in wood thus reflect those of rocks and soils on which the tree grew. This approach is applied here for the first time to carbonized archeological wood. Before proceeding to identification of the origin of the Notre-Dame timber woods, 1) the preservation of geochemical signals during carbonization was verified experimentally, and 2) a referential database of multi-elemental and Sr-Nd isotopic signatures in modern wood was built at the scale of the Seine River catchment. Although the carbonization led to volatilization and loss of some of the studied elements, it did not affect Sr and Nd isotopic composition of charred wood. Additionally, reliable elemental tracers for provenance were selected on the basis of the ratios of thermostable elements i.e., those whose decrease in concentration was negligible (< 20% at 800°C). The geochemical tracers were tested on modern wood from the 12 referential forests, each representing one type of substrate characteristic of the Seine River catchment area. Determination of the origin of modern wood could be achieved with an accuracy of around 80% and was strongly controlled by the 87Sr/86Sr isotope ratio, as well as by the Sr/Ca and Nd/Ca elemental ratios. The carbonized timbers from the Notre-Dame framework were characterized for cutting dates of trees and their geochemical signatures were compared with one another, and with those of wood from the referential forests. The geochemical signatures of most of the medieval woods were found to be characteristic of forest stands growing on deep silty soils, in agreement with findings from historical archives pointing towards an origin of the timbers in the south-east of Paris
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6

Romeur, Monique y René Maury. "Séries magmatiques arc et arrière-arc de la Sonde : nature des sources impliquées (éléments en trace et isotopes Sr-Nd-Pb)". Brest, 1991. http://www.theses.fr/1991BRES2006.

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Les volcans quaternaires arriere-arc de java presentent une importante variabilite dans la composition petrologique de leurs produits et dans leur distance par rapport a la fosse. Les laves des ces volcans montrent des caracteristiques en elements en trace typiquement orogeniques, compatibles avec une origine liee a la subduction. Elles ont des compositions isotopiques pb et sr un peu plus faibles que celles des magmas d'arc; les compositions isotopiques du nd sont similaires dans les deux types de magma. Deux correlations compositions isotopiques du nd-rapports th/ta sont mises en evidence: l'une comprend les laves arriere-arc; la seconde les magmas d'arc. A l'aide de ces correlations, trois zones geochimiques ont ete reconnues: un domaine arc, un domaine arriere-arc et un domaine intermediaire comprenant les volcans situes geographiquement entre l'axe de l'arc et les volcans arriere-arc. On propose que les magmas d'arc resultent du melange entre une source murb appauvri (comportant les caracteristiques dupal) et les fluides issus de la plaque subductee. Un melange entre un manteau morb enrichi en elements hygromagmaphiles (contamine par la fusion de croute oceanique subductee, sumatra) et les sediments subductes (par l'intermediaire de fluides metasomatiques) (java) genere les magmas arriere-arc. Les magmas intermediaires sont le resultat d'un melange entre les sources des domaines arc et arriere-arc. Un modele de repartition de ces sources est propose: il est compatible avec la remontee d'un manteau enrichi (domaine arriere-arc) dans un manteau appauvri superficiel (domaine arc)
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7

Yang, XiaoZhi. "Water content and H-O-Li isotopes in lower crustal granulite minerals". Thesis, Vandoeuvre-les-Nancy, INPL, 2008. http://www.theses.fr/2008INPL028N/document.

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Pour la première fois, une étude par spectroscopie infrarouge à transformée de Fourrier et par microsonde ionique des minéraux majeurs de la croûte inférieure et des péridotites mantelliques a été entreprise afin de mieux caractériser les mécanismes d’incorporation et les teneurs en eau de ces minéraux nominalement anhydres, et de déterminer leurs compostions isotopiques en H, O, et Li pour retracer les échanges latéraux et horizontaux de l’eau dans la lithosphère continentale profonde. Les résultats montrent que: (1) Les minéraux nominalement anhydres, comme les pyroxènes et plagioclase, dans les granulites de la croûte inférieure contiennent de l’eau en trace essentiellement sous forme hydroxyles et accessoirement sous forme moléculaire, avec des concentrations (exprimées en poids H2O) allant de 200 à 2330 ppm pour les clinopyroxènes, de 60 à 1875 ppm pour les orthopyroxènes, de 65 à 900 ppm pour les plagioclases. Les teneurs calculées pour chaque roche totale d’après sa composition minéralogique et la teneur en eau des minéraux varient de 155 à 1100 ppm. (2) Les teneurs en H2O des minéraux majeurs et en roche totale de la croûte continentale inférieure sont manifestement plus élevées que celles du manteau lithosphérique sous-jacent, suggérant des variations verticales de la quantité d’H2O dans la lithosphère continentale profonde. Un tel contraste peut affecter de façon notable le comportement rhéologique de la lithosphère continentale. (3) Les rapports isotopiques de l’oxygène des pyroxènes étudiés, et probablement les roches totales, exprimés en [delta]18OSMOW , vont de ~ 4,5 à 12,5‰. Ceci indique la contribution de matériaux recyclés de la croûte continentale durant la pétrogenèse des échantillons ayant un TM18O élevé. (4) Les minéraux de la granulites sont caractérisés par des valeurs de élevées TMD, avec des valeurs de -80~-10‰ exprimées en [delta]DSMOW; les minéraux sont le plus souvent en équilibre les uns avec les autres lorsque l’on considère leurs compositions isotopiques moyennes. (5) Les compositions isotopiques du Lithium mesurée dans les minéraux de nos échantillons de granulites, exprimées en [delta]7Li par rapport à Lsvec, varient de -13 à +4.7 ‰. Ces valeurs sont donc pour la plus part inférieures à celles mesurées sur les MORB (2 – 6‰). La dispersion des valeurs reflètent l’hétérogénéité de la source des granulites, et les valeurs bassent resultent probablement de la perte par diffusion de Li pendant la mise en place des liquides silicatées provenant du manteau dans la croûte inférieure. (6) La grande hétérogénéité des teneurs en eau et en Lithium, et des compositions isotopiques de H-O-Li indique l’absence de circulation de fluide pervasive au travers de la croûte inférieure, qui aurait pour effet de supprimer les hétérogénéités à petite échelle et de les diminuer fortement à grande échelle
For the first time, systematic investigations of water content and H-O-Li isotopic compositions of minerals in lower crustal granulites, as well as water content of minerals in mantle peridotites, from eastern China have been carried out by Fourier transform infrared spectrometer and ion microprobe. The results show that: (1) Nominally anhydrous minerals, such as pyroxenes and plagioclase, in the lower crust generally contain trace amounts of structural water, with their content (H2O by wt.) varying from 200 to 2330 ppm for clinopyroxene, 60 to 1875 ppm for orthopyroxene, 65 to 900 ppm for plagioclase and 155 to 1100 ppm for the estimated bulk compositions. (2) Water contents of minerals in lower crustal granulites from eastern China, and their bulk values, are significantly higher than those in the underlying upper mantle, implying vertical heterogeneities of water distribution in the deep continental lithosphere; the contrast in water content even affect the rheological strength of the lithosphere. (3) The O-isotopic compositions of pyroxenes in the lower crustal granulites from eastern China are highly variable between different localities (~ 4.5 to 12.5‰, expressed in [delta]18OSMOW values), indicating variable influences from recycled crustal materials on their protoliths. (4) The H-isotopic compositions of granulite minerals from eastern China, are mostly in the range of -80 to -10‰ expressed in [delta]DSMOW values, and these minerals are usually in equilibrium with their [delta]D values. The relatively high [delta]D of granulite minerals may be related with degassing loss of H during the genesis of granulites. (5) The Li-isotopic compositions of granulite minerals from eastern China are usually in the range of -13 to 4.7‰, mostly lower than those of MORB (2-6‰). They reflect the source heterogeneity and are probably results of high-T Li diffusion during the intrusion of their original melts into the preexisting lower crust. (6) The large dispersion of Li and water contents and of H-O-Li isotopic results indicate the absence of any pervasive fluids in the lower crust
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8

Le, Quilleuc Meryll. "Caractérisation élémentaire et isotopique (Sr et Nd) des dépôts d'aérosols sahariens sur la marge sénégalaise : implications pour la signature géochimique des sources". Thesis, Lille 1, 2019. http://www.theses.fr/2019LIL1R075.

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Les aérosols désertiques émis dans les régions arides et semi-arides constituent un élément actif du système climatique global. En effet, de par leurs propriétés optiques et leur rôle dans les processus de nucléation dans l’atmosphère, ils ont un impact sur le bilan radiatif et le cycle hydrologique. Ils ont également une influence sur les cycles biogéochimiques marins et continentaux par l’apport de micro-nutriments dans les régions où ils se déposent. Par ailleurs, les aérosols désertiques sont des indicateurs des changements paleo-environnementaux dans les archives sédimentaires. L’impact de l’aérosol minéral dans le système climatique dépend de la quantité de particules émises dans l’atmosphère, de leur distribution granulométrique et de leur composition géochimique. Ces paramètres sont cependant souvent insuffisamment quantifiés, en particulier dans la région du Sahara et du Sahel (plus importante source au monde), du fait des très nombreuses zones d’émission et de leur caractère intermittent. Les caractéristiques des retombées de l’aérosol saharien sont singulièrement mal connues ; celles-ci sont pourtant essentielles pour estimer son impact sur les cycles biogéochimiques, faire le lien avec les dépôts sédimentaires, et contraindre les modèles atmosphériques de transport. Une étude de dépôts éoliens a été réalisée sur la côte sénégalaise dans l’objectif d’améliorer nos connaissances sur la composition chimique des aérosols transportés sur la marge ouest africaine et la signature chimique des régions sources. Dans ce cadre, un capteur passif a été mis en place en 2006 à Mbour, permettant de construire une série temporelle continue de dépôts d’aérosols désertiques avec un pas d’échantillonnage d’une semaine ou moins. La composition élémentaire de la fraction silicatée inférieure à 30µm de 221 échantillons de dépôts a été déterminée (incluant une série continue de deux ans entre 2013 et 2015), ainsi que les rapports isotopiques du strontium (Sr) et du néodyme (Nd) de 63 de ces échantillons. En parallèle, une étude des sources alimentant notre site d’étude a été réalisée à l’aide de l’indice satellite IDDI et de rétrotrajectoires de masse d’air (HYSPLIT). L’étude de la série continue de dépôts 2013-2015 a révélé une grande variabilité dans la composition chimique des particules, suggérant une importante diversité géochimique des sources. Cette série temporelle a permis de mettre en évidence des changements saisonniers du flux et de la composition chimique, en lien avec les changements de provenance et de transport des particules entre la saison sèche (hiver-printemps) pendant laquelle les aérosols sont apportés par les alizés qui balayent le continent ouest-africain, et la saison humide (été) au cours de laquelle les dépôts résultent en partie du lessivage par les précipitations de particules transportées à haute altitude dans la Saharan Air Layer (SAL)
Mineral aerosols emitted in arid and semi-arid regions of the Earth represent an active element of the global climate system. In fact, due to their optical properties and their role in nucleation processes in the atmosphere, they have an impact on the radiative budget and the hydrological cycle. They also take part in many biogeochemical cycles in the ocean and on land through the input of micro-nutriments in regions where they are deposited. Mineral dust is also an indicator of paleo-environmental conditions changes in sedimentary archives. Mineral dust impact in the climate system depends on the amount of particles transported in the atmosphere, on their grain size distributions and on their geochemical compositions. Yet, these characteristics are often insufficiently quantified, particularly in the vast Sahara-Sahel domain (the largest source worldwide), due to the numerous emissions areas and to their intermittency. The characteristics of Saharan dust deposits are especially poorly constrained, although they are essentials to estimate the dust impact on biogeochemical cycles, to make the connection with sedimentary deposits, and to validate dust transport model outputs. A study of eolian deposits was carried out on the Senegalese coast in order to improve our knowledge of the chemical composition of mineral aerosols transported over the West African margin and of the geochemical signature of the source regions. For this purpose, a passive collector was set up in 2006 at Mbour, allowing the build up of a long continuous time series dust deposits with a sampling resolution of a week or less (down to 24h). Elemental composition (major and trace elements) of the <30µm carbonate-free, silicate fraction of 221 dust deposit samples was determined (including a two-year continuous time series between March 2013 and February 2015), as well as the Sr and Nd isotopic ratios for 63 of them. Concurrently, investigations on the sources feeding our sampling site were conducted with the help of the IDDI satellite product as well as air masses backtrajectories calculated with the HYSPLIT model. The study of the 2013-2015 continuous time series of dust deposits revealed a large variability in the chemical composition of the dust, suggesting an important diversity in the geochemistry of the contributing sources. This long time series brought to light marked seasonal changes, both in the mass flux and the chemical composition, that can be linked to changes in provenance and transporting wind systems between the dry season (winter-spring) during which aerosols are transported in the trade winds that sweep across West Africa, and the wet season (summer) when dust deposit result to some degree from the scavenging by precipitations of dust transported at high altitude in the Saharan Air Layer (SAL)
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Negrel, Justine. "Etude couplée des fractionnements isotopiques du LI, B et U dans des profils d'altération : exemple du bassin versant du Strengbach (Vosges, France)". Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAH001/document.

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Comparer de manière approfondie la réponse des différents outils isotopiques choisis (Li, B et U) durant l’altération chimique dans un profil déjà connu (e.g. le profil du Sommet sur le Bassin versant du Strengbach ; Ackerer, 2017) afin de dégager les mécanismes moteurs des fractionnements isotopiques de chacun de ces éléments pour faire le lien entre la réponse de ces outils lors de l’altération chimique et remonter ainsi au régime d’altération des roches. Développer les observations réalisées sur le profil du Sommet et les appliquer sur cinq autres profils d’altération répartis sur l’ensemble du bassin versant en se concentrant sur la fraction <2µm. Cela permettra de voir si les observations faites dans le premier profil se retrouvent dans les autres profils et si nous sommes capables de remonter au régime d’altération. Étudier de manière préliminaire comment évolue le signal isotopique de l’altération chimique acquis dans les profils d’altération au cours du transport sédimentaire et s’il est possible de déterminer le régime d’altération d’un bassin versant à partir des sédiments de ce même bassin
In-depth comparison of the response of various selected isotopic tools (Li, B and U) during chemical weathering in an already known profile (eg the Summit profile in the Strengbach watershed, Ackerer, 2017) to identify the driving mechanisms of isotopic fractionations of these elements to link the response of these tools compared to the chemical alteration to go back to the alteration regime. Develop the observations made on the Summit profile and apply them to five other weathering profiles distributed over the entire watershed focusing on the <2μm fraction. This will make it possible to see if the observations made in the first profile are found in the other profiles and if we are able to go back to the alteration regime. Preliminarily investigate how the isotopic signal of chemical alteration acquired in alteration profiles evolves during the sediment transportation and if it is possible to determine the alteration regime of a watershed from it sediments
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Bouchet, Bert Manoz Romain. "Structure de la lithosphère continentale de l'Ouest USA : contribution des isotopes du Plomb,du Néodyme, et de l'Hafnium". Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2014. http://tel.archives-ouvertes.fr/tel-01066021.

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La lithosphère continentale est physiquement et chimiquement segmentée. La cartographie des isotopes radiogéniques de roches plutoniques acides, représentatives de la croûte continentale, et de laves basiques, représentatives du manteau, possède des similarités avec la cartographie sismique de la lithosphère sous-jacente. Ces similitudes permettent d'interpréter les observations sismiques en étudiant leurs caractéristiques chimiques et leur âge. Les isotopes du plomb permettent de dater et d'identifier l'empilement de segments crustaux qui forment la croûte. L'écart des âges modèles du plomb avec d'autres systèmes identifie le recyclage crustal et le réchauffement de la croûte au dessus de la température du système plomb-plomb. Le système plomb-plomb donne également accès au sous-étudié rapport Th/U qui contraint la profondeur de la source des roches continentales. Certains échantillons de l'ouest U.S.A. proviennent de la croute inférieure, et se sont formés par l'extension crustale ou par un flux de matériel au sein de la croûte. Les isotopes du néodyme et de l'hafnium marquent la fusion du manteau lithosphérique enrichis sous le Colorado Plateau, une région où est observée le détachement du manteau lithosphérique sub-continental. Ce manteau fond par décompression adiabatique, par extension localisée ou remontée asthénosphérique engendrée par la convection locale. Au final, l'association des systèmes isotopiques du plomb, du néodyme, et de l'hafnium avec la sismologie est une approche puissante pour étudier la formation et la déformation de la lithosphère continentale.
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Capítulos de libros sobre el tema "Isotopes Li et Nd"

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"te a c ri hanbiiq li ues draw on many aspects of recorded past cast skill is that the statistical techniques generally cao ss r o re cliaattie ty d w in i th thEeNS cl O im . aItne system, not just those perform poorly in northern spring, with cross­ forecasts o , nanaunmd be mruo lt fipo le ad li dnieta io r n to simple linear validated anomaly correlations <0.6 for forecasts even operational use. These ttohoelrssitn at c i sti rceagl re to ss oilosn -a braes ed just one season ahead and <0.3 for forecasts two antianalogs (Livezey lude analogs an idnd se aam so pnesdapheerasd is . te S n im ce p l ( eapceorm sis btiennacte io onfo th fepeSrS si Tss te , nocrethaenidrCClain mate Normals ( OaC nd N ) B a ( r H ns utaonng 19 e8t8a ), l . O1p9 ti 9m4a ) l , tcilm im eao to fltohgeyy ), easrh . ow just as much, or more, skill at this l P in re eio se n n ic d al Correlation Analysis (CCA) (Barnett and Even if the statistically based SST forecasts were War adrda is ocrrfiemr in 1a9n8t7a ) n , a ly asnids (M eig a e ry novnecatnodrSatnoarleyy si s19a8n5d , p th earn fe -c pte , rf heocwtreevlear ti , o n th sh e ip hsisbteotrw ic eaelnrS ec SoTrda no sh moaw li sesla es nsd -d beav se e d lo ponndnFeoulrlaalndne1 tw 99 o 1). More complex methods precipitation even for regions with a strong ENSO skill scor eedso (e f . g o . p , er Lao ti nognaertksal. ha1v9e also recently been influence. In such regions, precipitation anomalies these tools has been mar lgpirneacl ip in it 9a7 ti ) o . nIn fo general, the typically show a consistent ENSO relationship in 75-much more skilful in parts of the t h tr eopeixc tr raetcrao sts using 80 per cent of the ENSO episodes this century. How­ et al. 1993). In the extratropics, statist s ic a (e l .g p . i , cWsba ut ever, even the best performing statistical SST pre­ offer little encouragement for more reliable m dr e o th uogd rd s b di e c tw tio enen sc ohbes mes have ht Pacific SST oefrv0e .8 d -0 a .9 ndcp ro re sds-ivca te li for two se d d ate aso t n ro dspa ic caolr re e la atsitoen rn s p cu re r d re ic nttiosn ta steexocfepEtNwShOenoursw ed it h in EcNoS nj Ounfcotrieocnasw ts i th (e . tgh . e , n co orrrtehleartn io nsuomfm th er e through fall. Thus if th hee ad an ionmtahleysB ta atrin st sitcoanldarnodu gh Stmp it rhe di 1c9 ti 9o6n ) . t ha Wter el nao te w s to fo cEuNsSoOn , m th ieghotbr served SST igs iv 0 e . n8irnegs io tr noanlgpE re N ci SpO ita tyieoanrsw , w ith e a in ndpatrh ti ecuplraerd . iction of central and eastern Pacific SST pitation eawsio th na abn ly o m ex a p ly ecctotrorem la atk io e such year nps re odfi0 ct . i6o -n 0 s . 7ofdpurreicnig ­ icsorcro el nastiisosn -o i v .e e . r , a in ll aybeo ar ustwhialllfboefsau ll byse ta a n rs t . iaT ll hyeleasvse ; rtahgies tent with experience (Barnston and Smith". En Droughts, 59. Routledge, 2016. http://dx.doi.org/10.4324/9781315830896-41.

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"Jeu as nte -A A u fr g ic uasnt. T lo h w ese in tropospheric jetstr ea le mvc el l , u de antdhew su e b st t ro A pi f c ri aclan ea st m er ildy -, deve s. These fast-moving upper pre Spoa lo re pdendes th srpoou li gch ie s s . ound early warning and disaster ltehveeltw ra inn cieties in sdpsoh rt avoeffamr-o re is atcuhrien , g m im opmaecn ts tuwm it , hproelslpuetcatnttso , reeflfyorh ts e , a w vi h ly icohndp ev o e st l -o dpiisnagstceorurnetlr ie ie fsa , ned sp reech ia alb ly ilA ita fr tiicoan , a an tm dop sp es htesr , ic to dgyentahm er ic w s. ith many other aspects of the tdo is atshtee rs s . evIen re imm ake them m creas peadc ts vuo ln fed ra ro o u re ghatn bility doafnmdsooo re th vulnerable Tropical cyclones have both direct and indirect severe consequences of natural disasters c iet eyrn to a tu t r led to th haeliam ss poacc ia ts t ed onwK ith entyhaensrtarionn fa gll. w T in hdes , doic re ecatniwmapvaecst , saanrdefdoerc la N ra attiuornalofDtihsea st 1e9r90Rseadsuc th ti eon In t ( eIrD na N ti D on R a ) l D by e ca th deeaen xc yescsyicvleonperew cip e ith it iant io th netw ha etstoec rn cu Irnw di haennO th ceeaenffeex ct tsenodfpUrnoim te odteNdaitsiaosn te s. rpTrheevemna ti joonraonbd je cptrievpearoefdInD es NsD th R ro iusgthocolv im er atK ol eongyiac . a l It sh hit the Keny arneccoorod uld be as s t . shTohwen th o a ted ind tino th cayt rect ecflto he fe nce ts ahvaaosileafavbe le rcdo ev n e ce ny dama lo rgp te e, in dgc in otuen rn tr aiteiso , ntaol re adcu ti coen , l os esspo ecially in the cyclone, however, occur when the cyclone is far from often as so acnid at esdocw io it ehconnaotm ur iacld di issa ru st petrisofn li , few , hpircohpea rt ryet it hserceegn io tr n e , butthsetrie ll bayt tra in cttesrtfhee ri n re g g io wniatlh wi tnhdes to n w or a m rd aslh at etlip tu tdoess hi tfhtattheap re o st p -d re is vaaslteenrt re iln ie f and . r T eh haeb se il it cao ti uolnd circ Culloas ti e on patterns of the many developing general ciin rc te urlaac ti t o io nnsohvaevrerbeegeinonoabl winds. the regi soenrvaendd between the cou A n tr n ies the extra-includin egw . th d e im feuntsuiroen re to cu rnraetnucrealocflidm ro at uegh variability, tsryosp te ic masl , wmeiadtlhaetr it u sy dsetewmesstle ik r e li etsh , e N fr oorn th ta lAatn la dntb ic lo coksicn il g ­ tchuerrternatdigtlioobnaallcsopn ac cee -r t n im aebopuattttehrenspootfengtlioablacths, a n is geth in e T la e ti l climate, Ke l o ec n o , nenae st Atlantic pat nyan rai cntfiaolnlsanhdavEeNaSltseor ns b , eeanndobEsuerravse ia dpbaetttw erns. inclu O, quasi-biennial oscillati eoenn , h cl u im madt ing the space-time ch an eaecvteinvtis ti etsh . roSuug ch h e im nv piarcoanrm ac e te nrtiasltidces gr oafdaetx io tre ts are currently subj nembey intraseasonal wave, and so forth. The influence of the of many studies and debates, as reflected in the 19 c9t5sw co a m te prlebxod topographical patterns and the large inland Intergovernmental Pane inland wat ieersbiosdv ie e s ry insc ig lu n d if eicL an ak teinViKce to nryiaa . , w Th h e ic h la h rg aess in c d ie inctaitfe ic d ‘d aisssceesrsnm ib elnet inf olfoncC lim lim a ate Change (IPCC) an area of about 70,000 km2 and is the second largest the recent climate trends l ’ u . eInPcCeCof te change, which freshwater lake in the world. The complex topo­ ever, that no conclusive evidence ( 1h9u9m5a ) nnaoctteid vi , tiheosw in ­ K gr i a li p m hical patterns include Mt. Kenya, Mt. human-can be derived fo anjaro, and the Great Rift Valley with its accurate inmdeutcheoddscf li omrattheed ch et aencgte io nsiagnnd al s a tt urn ib ti ult io mnoroercaltitm en a d te anptroccheasisnesofcamnobuentoab in ta s i . n D ed e ta fr i o ls of the regional natural/anthropoge f Anyamba 1992, Fremming 1970, manOdg al F lo in 1d9 la 9 te 3 r , acn ha dng ac e cu si rgan te a ls cla im re atanv ic a ilab ( lhe, u m to agne -t ihnedrucweid th ) ad celq im ua attee 1966. tch li e m si ast . ecSheavnegrees , icnocnes lu eddqau ta e n for testing various hypo­ patterns of extreme clim iantge ces ecvheanntgseosf in htuhmeasnp -a icned -u ti c m ed e like drought, would cDorm ou pgohntenatnsdoofthnear tu erxatl reme climate events are normal h ca ig ll hlfiogrhtceld ea brym th it eigIaPtC io C n . and adaptation policies, as iam nd pacco ts m m of onthpehseenon me n in atew ra o n rl nduwaildceliemvaetreyvyaeraira . b T ili htey men Gtlaolbadlegcroandcae ti ronnapbrooucte ss heusmaannd -i nsduusc ta eidn ab ein li vtiyr on o ­ f m an idn im ad al eqiuna the de atural disasters, however, te drou v g el hotpesdhoccokunatbrs ie osrbw er hserheaveef fi b ci aernettniaetsurlaeld re to so u een Conference th rc ees vita on o rga Enlnivstao ir t most o io nnmeonfs ocioecon t the anUdn it oemd ic Naat ctivi­ Sustain iaobn le s". En Droughts, 84. Routledge, 2016. http://dx.doi.org/10.4324/9781315830896-60.

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"T cu im rre e n tl Sycahleeasd ) qu aas rte wreeldlaatst he thLeammounltt -i D na oth io e n rt aylEIaR rt I h , odtrhoeurgm ht ajporrem di ocd ti eolnprw ob il llem re s q . u T ir hee the resolution of hOabvseearnva im to p ry o rt oafntCcooluupm le bdiamoUdneilvecrosm ity p . onTehnet, sea lt ehfo fo urgthsp ex hteernes , io onntaogfloorbeaclasdto in mga , in boatnhdth th eseeaorcee dva saonlnacn es diantcm lu odse ­ m in acn lu ydeodf ( t C he a rs toyn pe 1s9o 98 f ) m . ethods discussed above are uomciesamnatacnhdbaettmwoesepnhtehree . fl Fuo xe rsmaatntyhearbeoaus, n d th atr io ie nsoofftthhee rep F li o ca rtE in NgSaOn , d c , ur in re nstom co eupclaesdesm , oidmep ls roav re in cgapoanb le thoefo of frtehaelsie st iwcillalnrde -q suuirrfeacse ig coupling may be ess eenatd ia dli . tiA on ll tshue cc ecsusrroefnetmgpein ri ecraalt / isotn at i o st ficcaolumpe le th dom ds o . dFeo ls rirnesptlain ca ctee , a model parameterisatio nificant improvements in the SST anomaly patterns in the equatorial Pacific that th ry elraeyqeu rs ir , ecd lo m ud osd , erlad im inasp ti oonf , saun rf dacceonpv ro ecce ti sosn es, bound­ have many characteristics in common with observed to a quick solution, but, ro g v iv eemnetnhtesiam re p o li rktealny . N to onye ie o ld flEeN ss SsO uc cceosm sf puolsiin te tsh . eCm ur orreentdim ffi ocduelltspa ro re blceomnso id ferreapblliy ­ imp Iatcsthoofud ld ronuogthbte , they are worth pursuing. ce of the p ca hteirnigcc th ir ecuslpae ti c o if n ic peav tt oelruntsioinnoafgtihve en SESNTSaOndepaitsm od oes . ­ tehxe prospects for im forgotten, however, that not all of However, it is precisely this problem that must be no ctlufsuilv ly eluynodnersse ta a n so pnraolvteidmde ro sc uag le hst . p A re l dictions reside solved. Just as the ‘average’ daily weather is rarely of climate variabilit d y , th th eem re u l is ti aanmnpulaelteo th doeucgahdawles ca dloeo ce bpsteuravleda , idthteo ‘ ucnadneornsitcaanl’ diEnNgS th Oan id aeauissefm ul orceonastcroun ct ­ e2x .1 is c t ) e nc aend -e th .g e . , sien the time series o vidence for its for prediction. To reach their full potential, coupled distributions of rai cnuflaalrl ( cFhiagnugrees2i . n2ftrhae in f p al rlob (F ab ig il uir ty eim nd oidveildsun al eepdas to t E be N S ab O le etpoisroedpe li scaa te ndt he th eeivroleuv ti ooln vi nogfnoefw co duep velopments in data an ). Very recently, extratropical atmospheric and ocean interactions. There is lesdommeoedveildsehnacveeosftd ar etaeld ys t is oaonpdeinn the accuracy The most optimistic expectation is that once that may have a somewhat c ad d a if lfv er aern ia t t io unpstihnisEN fie S ld O . cEoNuSpO le , d th m ey odw el i s ll bheavaeb le cotnoqhueelrped id etnhtei fy chaanld le npg re edio ct ftmheeasiun red by the ocean s character, as other modes of climate variability. This may include Zhang te ertananl. ua1l99 ti 7 m , eFoslc la al neusr fa ( cKeleteemmapne ra et tures, from links between ENSO and the climate system not yet are now beginning to fin ddeatanlu . m1b9e9r8 ) o . M al. od1e9 ll 9e6 rs , m dis ocdoevlesremdaiyntahiediimnpienrv fe ecsttiogbaste io rv nast io onfaplodsastiab . lIemcplriomvaetdem ab e il cih ty anoin sm th seinde th ca edN al otrothmaun lt d i tropic f potential modes that link ocean basins, such as ENSO-and Barnett 1996). There is adlescoad ev aalltiPm ac eifsiccaf le o r ( vari­ related variations of SST in the tropical North Atlantic, ENSO links to rainfall may come an id dengcoed th ep aetnsLoam ti e f rece In n tl aydddiistc io u n ss etdoboycE ea n n fi -e altdmaonsdphMea re y er c o ( u1p9l9 in 7 g ). , new nointutdheeo se fcE ul N ar S O va riitas bility in the str ding generations of models need to include realistic land-southern Europe (R eolpfe -le wes .g k . i , a in ndneonrg Ha th th lp e e rn an dAfm ri acga/ ­ rae tm ali oss ti pchm er oedeclosuopflitnhge . la Snudch su rifm ac peroavnedmie ts ntvsegientvao ti lovneaThheeadp , r m ed aiyctaalbsio lity of ENS rt 1987). and adequate descriptions based on observed data of in Northern Hevm ar iyspohnerdeecOa sp d , rail on ntgiem ( e to s Ba c a ls a a le fse , w e sp se eacs ia oln ly strheep re isne it nitaal tio ve nge in ta t m io ondesltsa te is . c W ur orrekn tl oynbleainndg -s m ur afiancleym 19 e9a5n ) s . (i I . n e ., additio meda et al. driven by the development of coupled models for over several cdheacnagdenes , sis ) n ec a th u lso e la r ‘ itvnyfpairciaalbio li rty in the climate climate change projection over the next century conditional ENSO probability l u fo ernecceassetsxsi . m pe Fpcolteeds ’ e values (Dickinson et al. 1996). the Gulf Coast of the United States shows reaxaam sonal Significant advances in coupled model-based ENSO signal for both the first and second half s o tro p n le, f th g e". En Droughts, 65. Routledge, 2016. http://dx.doi.org/10.4324/9781315830896-45.

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"n ar eegattaikveenco to rr e im la p ti loynsa , p th hy essieca ‘ ltelliencko nnectio key va between ntphaet te lo rn ca s l ’ w (1 a9s7o2n ). tFhoellpoowiinntgosfoemmeeirngc in on gcilsusc iv oentw ai onrekdbiynoLtahm er bsm Gl aapnstzrioeatblael . a1n9d9t1h ) e . widely distributed one (e.g., see (e.g., by Berlage and DeBoer 1960), Professor Jacob pressure f an pdr ec wiapsi ta atiW on a , l ke te r m produced teleconnection Bjerknes at the University of California at Los modes of interannual blcel im to a te idve perature, and surface Angeles made the key step forward by demonstrating nise today, including the South anerrita if nbyi li tthyethlaatrgweestre scale that the atmospheric teleconnection patterns were North Atlantic O Oscillation and c o th g e ­ p eq a u rt atoof ri aalcPoaucp if liecdOmco ea dneaonfdinttheer ac gtlioobnalbaettmwo ee sp nhteh re e was Inaba le d d to it icoanr ry to scb illation. (Bjerknes 1966, 1969, and 1972). It is now clear that of fortunate circu omuste ing a first-rate scientist, Walker other parts of the global ocean also participate in the the art of statistics htaahn is work because of a confluence Southern Oscillation, manifested through changes in matical tool of the ob d se cdeesv . e F lo ir pset, shortly beforehand, sea surface temperature and the overlying atmos­ also a very ab rvational dscriaepnicdelsy . aWsaalkm er atwhaes ­ phe B ri ycctih rc e u la la ti toen. 1970s and early 1980s, climate o st fat ti hse ti cIsnd (W ian alM ker le1 99 m7a ) t . h H em av aitn ic giatn ak ewn ho understood scientists were able to document the relationships gained the oppo ertteuonrio ty lo tgoicc al Departme th netijnob19o0f3h , e h ad ehRyap sm ot uhsesso is neda nd byCaB rp je ernktneers 19 in 8 2, mwoh re odd is e c ta uisls ed (e . tgh . e , m re aqtuhierm ed ata ic a la l rg oepesrta aff capab alreryoofupteh rf is orsm tu idniges, m w an h u ic ahlT So hue th ceorunplO ed sco il cleaa ti n o -n a / tEmlosNpihneoreasvaaricao ti uopnlecdenstyrsetdemo ) n . W ve a ry lk p er raw ct ais able to t m io ankseoanmeax jo te rne si f v fo e rt d a to ta so se lv ts e . tShoeE th NeSeO qu a ( t E or l ia NlP in ac o i / f S ic oiustnhoew rn co Omsm cil oln at liyon re ), f er a r ed p h to ra saesA ra n in oftah ll e , rkaencaalcp ti rvoib ty le m th aotfh pr aed dicting Indian monsoon coined in planning documents for the international by the earl yyfyaecatrosrowfasthtehattwietnh sta taidejru te t st dbe in c om th eep1 os 8s7i0 bl s e . Tmreonpti . caDlO ur cienagntG he lo b 1 al 98A0tsmoasnpdh er 1e99 (T 0s OGaAs ) ereix es p er o i­ flsaurfgfe ic -s ie cnatlence li amr-agtleob va arl ia d ti aotnas . to de hsccre ib n e tu raynd to agnaatlh ys eereom ur p iri ucnadl, e m rs o ta dned ll iinngg , aonfdtthheeo re p ti hcyaslicsa tu l di m es e c in hcarneiassm ed s 192 T3heansdtu1d9 ie 2s4 , bWyaW lk a e lker and others (e.g., Walker aad ss voacnicae te sdinwiutnhdEeN rs S ta O n . diAngdettealielceodndnie sc c u ti sosn io pnao tt ferrencsen in trge lo la b ti aol) nsshuirp fa s ce exp is re te s d su rbeertawnedenB li lsasrg1e9 -s 3c2a ) le s h ( o i. w e. e , d n that the TOGA era (1985-94) can be found in Trenberth patterns -in particular, tphaettIen rn d s ia n an sdum re m gional rain efaarl -l et aTl. h1e 99 i8deanntd if i A ca ll tainone ta o l. f 19 so 9m6. e of the physical v ra aitn io fa nlal. l W ev a id lk eenrc ’s erfeosreatrhcehepxrio st veindceedo th feefr monso an ir osrtgaonbisseorn ­ m rev ec it h a anism ed conne l c is t e io dnsi nt aesrseosct iated with patterns. in A W se a ri lekser’ osENfp SO has st ruedciiepsi ta w ti i o th n g re te alte ly -glo more wHoerbcaal-ls le cda le tpk did no hi tsattthee rn hav Soofuitnh terannual climate variability. complete data sets (e.g., Kiladis and Diaz 1989; expected because, efotrhe re a im e p rn acOt scillatio sons th tahtartemma ig n. htI in unh itia nc alveel ly ar b , e h th einsrReocpoenlfeiw rm sk eida se nvde ra Hlao lp f e th rt et1e9 le 8c6o , nn 1e9c8t7 io , ns ansdu gg 1e9s9 te 2 d ) c so o o rr n e la ptr io ec nispib ta et t w io enenwtehaekepnreed ss uarbeopuatt te th rn esta im nd e m th oene ­ cboynW ne acltkieornsa . ndRootphee le rs w , saknidaindde nt H ifi aeldpeardt di ( t 1 io 9n8a7ltaen le-were discovered. Th y 1989) attempted to improve the usefulness of tele d ­ taitmtehemomsitdodf le thoefetah rl eec tw or ernetliae ti tohncsesnttruernyg , th beuntebdyag th a a in tcdooncnuemce ti notn patterns y work ha ing regions foorfstehaesognlaolbcelitm ha att , eipnreaddidcittiioonnb to y fille Adc in ru c w ia alspaap rt hyosfictahleepxipcltaunrdebteheantfro em rg aoitn ten atio ed . to be a m ls e o re lhyadshroew la itn io gnssh ta itp is stiw ca ilthEN EN SO SO -p rtehca ip t it w at eiroenhliignhklsy , t te hleecSoonuntehcetrinonOp sc aitltleartn io s. n A ju rsetvaisewaonfk fo nrow th leedogbesaeb rv oeudticdoennstiisftieendttfhreom se aespoin so sdaend to reegpiiosn od seo . f T th h e ey g p lo a b rt eicw ul haerr ly physical explanation precipitation was associated with ENSO in at least 75 e". En Droughts, 56. Routledge, 2016. http://dx.doi.org/10.4324/9781315830896-39.

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"a (o m ft oeunnti ) n an cdom th p e arison to som inten duration of tehenodrrmyaplero io r d. avTeh ra ugse , b cu y l ti a v lt aetr io in ngprtahcet ic cerso . p, genotype, planting date, and m th u es sesid ty ef iann it d io ndsu . raM ti eotneoarroelotghieca key characteristics of Agriculture is usually the first economic sector to phe t be considered as region spe lcid fi rcosuignh ce ttdheefiantim tio onss ­ abreeao ff f e te c n te dqub ic ykd ly roduegph le ttbeedc , aeusspeec so ia illlymiofis th tu erepesruipopdl ie osftsaotm io ric cendaoerfen diti ini c ti l o im on astethraetgriemseu lt dienpe deficiencies of precipi­ moisture deficiency is associated with high tempera­ on the ns differentiate me n te doernotl . ogFiocraledxraomupglhet , tduurreisngan th dewgirnodwyincgon se d a it sioonnsi . s T cr h it e ic a ti l m in in tgheofdertaeirnm fa i l ­ llm es asgn th abna si ssom of e th sepencu if m ie bderthorfesdhao ys l with precipitation nation of impacts. Crop or forage yields may be nor­ (e.g., itude of the deficiency over so dmreap th e e ri rod th o an f ti t m he etm im al eloyr ( i a .e b . o , vceo in ncoirdm in aglwdiu th ri n cr g i ti acadlrpohueg no hltog if icraalinsfta ag ll esi ) saOsrm ga unc fo h r Britain, fifteen days, none of which received and effective (i.e., low intensity and high soil infil­ in thos iz aeats0. rieogni215 on 93m6m ]) . oSfupcrh ec a ip idteaftiinoint io [B n ri is ti suhnrReaailn is ftailcl trat H io yndrroaltoeg ). ical droughts are associated with the effects c se oam so mno al n . an M d os etxst where precipitation distributi m en e d te eodropleorg io ic daslw dr i o th uoguhttrd ai enff in al oln is of periods of precipitation shortfall on surface or sub­ relate actual precipitation depa itio a n re slsaukre fa cleevw els a , tegr ro su upnpdlwya ( tie .e r) ., rsa tr th ea emrftlhoawn , rweistehrvpor ir eca ip nid ­ a ti mmoeun sc tasleosn . H monthly, seasonal, wa rtteurreyse ar t , ooraavnen ra ugaeltHay ti dornolsohgo ic rt aflald ls r o ( uDgrhatcsuapreetusaul. al1 ly 98o0u , t K of le pmheaSse1o9r8l7a ) g . are Aegqruiaclu ly lt uvraarliuam ble a . n perceptions of these conditions tdhreo ug o h cc ts u . rrM en e c te eoroof lo g m ic e a te lod ro ro lo uggihctasl re asnudltfargorm ic u p lt ruerca i­ l m on etperoercoilpoigtiacta io lddrroouugghhttto li n a ks various characteristics of pitation deficiencies; agricultural droughts are largely and potential nesvhaopro ta tr gaenss , gdriifcfuelrteun ra cles im bpea tw cts, focusing the result of soil moisture deficiencies. More time deficits, and piration (ET), seoeinlawca tu te arlien la o ps th es erbceo fo mrpeopnreenctispio ta fttihoenhdyedfr ic oileongciiceasla sy re s te d m et e (e c . tge . d , cdheapreancd te ern is tto ic nsop re fvoa rt i h li . ngAw plant’s demand for water is reservoirs, groundwater). As a result, impacts are out growth, and s t he ofphtyhse ic al sp eeactih fi ecrcpolnadnitt , i ons, biological of phase with those in other economic sectors. Also, the soil. and biological p it rsopsetratg ie esooffw riv a e te rs r ) i n is hoyfd te ro nlougsiecdalfo st rom ra ugletispy le st eam nd s ( ceo .g m ., preets in er gvopiu rs r­ , dorfocu ro gphst sh Aonu ld opaecrcaotu ional definition of agricultural poses (e.g., power generation, flood control, irri­ example, adted fi icfifeen re tnstub st natge fo srotfhe cr voap riable susceptibility gation, recreation), further complicating the sequence stage wil soil moisture idneavneleoaprm ly egnrt. o w Fo th r a in n d th q es ueansttiofriacgae ti osnyso te f m im sepsaccatlsa . te Csodm ur pientg it idornoufg or htw , aatnedrrseoq il u ir m em oi lsthuarveeliist tle su impact on final crop yield if top-conflicts between water users increase significantly. moisture en ctosn . ti Hnouw es e , v ffi ear ci , einft th teodm ef e ic eiten early growth The frequency and severity of hydrological drought result. substantial yie c ld y o lo fsss ub m so aiyli ( s19o6f6 te ) n de dfeifniendedaadtrotuhgehtr iv yeerarbaassionnescian le . whW ic hhiptphlee the The impacts of drought are crop specific because a ru gngo re ff g . atLeow ru -n fl oofwfifsre less than the long-term average betw m ee onstcrw op ea s. thPelra -s netn in s g it idvaetepshaenndolm og aitcuarla ti s o ta ngepserv io a d ry stfiomremapney ri osd tr efaam lls s . bIefqu th eenca ie cstuhaalvfelobweefnordea te srem le icnteeddahlisgohv te a m ry p between crops and locations. A period of hydrological drought lioswc on a si cdeerrtead in tothbreesihnop ld ro , gr th es esn . d se rnysic ti ovnedi era g ti roonts ur wt hmeasy tr ecsositnhca id teocw cu it rhsiancarsis ti occailatw io enatw stage for one he it r h -b Hio li w ty e v th ear, ttm he usntubmebeexrco ee fddeadystoanddeftihneelaevheyldorfop lo rgoibcaa ­ l c ca ri n ti coafltesn ta rgeedu fo crea th neotrh is ekro cr fodpr . o A cr gorp ic while missing a drought period is somewhat arbitrary. These criteria ught ium lt pua ra cltpolnancn ro in pgs will Tvhaeryibm et p w ac etesnso tr f e am hy sda ro nldog ri ivcearl ba dsr in osu . ght in an". En Droughts, 41. Routledge, 2016. http://dx.doi.org/10.4324/9781315830896-29.

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"ahcutm io annslairfee , m pr oosptee rt f y fe , c a ti nvdep if roddo uctive capacity. These is a critical element of the hydrological system. fervoem nt . o T ne hena ty tu preaslohrafzoarrmdstoofam no it n ig eaitn io nadavcat nce of the Information on the status of snowpack conditions can m ther. Droug iv hitt -i reeslavtaerdyfporroevciadsets co onfsb id e e lo ra w b -le noardmvaalncse tr dealm ea f d lo t w im aend fo rrerseelr ia vbolierf th ro it m ig ati e in tshioosne act diou u s se io dnfsoraroet , h e for the most part, different levels. gation is the indaetnutrie fi coaf ti ohran za artd ural hazards because of •Monitoring and early warning refers to activities with previous droughts a n of t . heAifm ir psatcsttsepa ss in ocm iat i e ti d ­ tdheacti si pornovm id aekeirnsfo at r m al a l ti l o ev neltsho at ftchaenobneseutsoefddtroouaglhetr . t w th ietshefium tu praectds ro (a ungdhtotehvee rs n ) daarnea li skseelsysm to enbteoafsw so hcei ther This information can be used by planners, emergency actions can be identifie n d ts. From this point, spec aitfeidcimmapnlaegmee rs n , tpporlo ic g y ra amnmdedsecainsd io pnom lic aikees rs th , aatnwd il o l th he elrpsttooo fu f t ur im epdarcotus gh atsseovceinattse . d Pa rttoIV re edm uc pehatsh is eesim th peacr ts of reduce the risk associated with the hazard. Moni­ geographical settings as wwie th ll adsrom ug et hhtodionl og viaerasinoguest to doa ri cat tia ng activities include the collection and analysis of quantify these impacts. Part V considers adjustment user o , ndo at fadaptraodpu ro cdtudcetvsetloopdm ec einsti , onanmdak th e e rs caonmdm ot uhneir ­ a an nddaPdaarpt ta V ti Ioncosn tr caetn eg tr iaetsesemopnlopyreedpatroed re ndeu ss cem im et phaocd ts ­ h in aza s r . dDsabtuat in a cludes not only physical data related to olo the definit lisoon so ocfiavlualn ne drabb io il lio ty g . icA al d co a m ta ptrheahtenassisv is ethgaavtg io ie n s , pr iong st ria tu m ti m on es alaanrdr an a g ct eim on esn , ts a /c nadpapco it liiecs ie , s miti­ drought monitoring system would include the collec­ imp e a ct bseo en f dr oorugchotu . ld be employed to reduce th th aetp ti roenc ip o it f a tio cl n i ) maastow lo el gliacsals tre daam ta f lo ( w e. , g r . e , se trevm oi prearnad tu grreouanndd ­ t • oPrienpcarreeadsneestshe re fleervseltoofprreedaidsiansetsesraocr tivities designed w se a n ter levels, soil moisture, snowpack, and remo improve oper­ cast ssedodfataagfrriocm satellites. This information is useful in ftoerley ­ aan ti on eamlearngdenicnys tit ( uet . igo ., naelacra ly p ab w il air ti neisng fo rsryess te p m on s, d in ogpetro ­ itnod ri i n ce gsatnodte ra acru ly ltw ur aarlnianngdtehcyhdnrioqluoegsi , cianlcldurdoiungghtth . e M us oeno i­ f u at sieofnuallfpolrands) e . no Fto in rgdrpor ught, contingency plans are them in a histo kriccu al rrent d ogrammatic responsibilities; contex ro t, u is g h th teco su nbdjie ti cotnosfaPnadrttIoIIv . iew p im ol p ic rioevsinbgetiw nf eoernmaatn io dnw fl iotw hi nonlesveev ls e ri o ty, im and coordination between levels of gov fergnomv pac eenrtn ts m , ean nd . t; d •P ec re is diiocn ti / opnolriecfyermsatkoerascw tiv it it hieasdtvhaantcepd ro fvoirdeecauss ts eros and D f the m sh a ro l ught i oul pdarntoosfan th i e nsidi t be vi ecw li e m ou aste nat d as m of ural hazard tha erveilrytuaalp ly hyaslilcarletg is pihoaensn no . omIrt ­ o ­ a fo crcm ur s r , ebnu ce tporfodbraobu il g it hyt . These forecasts can take many enon. Rather, drought is the result of an interplay p n re ddi in ct tieonnss it . yoFrorseecvaes ri ttyo ) fiso ccurrenc accu ursaucay ll yiaes so (t c im iat e e , ddw ura s highly viatrh ti o th n e , w be attw er eesnua natural event and the demand placed on between natural iable be consi pdpelryedbyrh el uam tiv aen -u to se ssoym ste emlso . nDg-rtoeurgmhtasvheo ra u g ld eidm ro puogrh ta ts ntincom ns oishtapzaarrtdssoafntdhe is w pa orrtlidc . ulLae rl deration for drought fore aydltiimm it eed is f a or condition of balance between precipitation and so d casts as well n , eva M po atnry an dsepfiirnaittiioonn . s of drought exist; it is unrealistic a in ncdorepco is riaotnem th akers are given ample opportunity to to expect a universal definition to be derived. Th the imple imseinntfao ti romnato io fnmiin ti g p at liaonnn in pr gogsrta ra m te mge ie s s . sDpreocu ti g ve htc as anfboe ll ogw ro s: u pe mdetbeyortoylpoegiocfald , isc hiypd li rnoalroygipcearl ­ , c lo agse ts reof is m al estoeoarno lo im gi pcoarl ta d n ro tudg is httinacn ti don th boe se tw oefenhyfdorroe -­ ian gric ical drought, especially in regions where snowpack so cco io rup ltur ec o o ra ntaels , d an omic if d f fe re snotc ioeco actors ipnhy it s n ic oaml, ic b . s defini io E lo agcihc al, d is a cipline tion. It mu nsdt /o be r". En Droughts, 46. Routledge, 2016. http://dx.doi.org/10.4324/9781315830896-33.

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"scto th ara ti rsetc ic te s d ( M mo OdSe ) l . f S or m ec it ahstadnad ta are called model output 1994). The state of ENSO is only one of many factors obs terevveedn SS gi T v en a perfect SRSoTp el feow re sckais ( t 1 -9 9i7 .e ) ., shtohweu (K se r d is hn to aKfuom re acrae st t al t . h1e99I5n ) d . ian summer monsoon m to oid ts elEuNsS ed O -a r t -N t C he E P cu rrent operational atmospheric Ward et al. (1993) discuss the useful level of skill In their study e , la ftoerd ty r -a fi i need vne fa lylspastu te brsn ta snfto ia rlpa ra d c ju ti sctamleun se ts . m of a d tr eop in ic a re l al n o ti r m th e A by f ri tchaenU fo KreM ca e st tse or th ol aotgihcaavleOb ff eiecnee (h xianm dc in aesd ts ) fo bra se th d e on specif e ie a d rs ( oofbsseeravseodn ) alSS fo Trew ca esrtess re in la ctei on 1s9h8i6p . swTih th esgeloabrael ly ladrigsetlry ib ubtaesdedSSoTn , SS st Tatiin st itchaelm ea o ch d el sism imulation wapserrieopde at 1e9d50 th -i 9r4 te . enEa ti cmh es s , e w as hoenraelpSoonue th n t. A O tla vnetrict , hean la dstade re claad ti e v , eltyhesm re aalll -ti EmNeSfOo re ccoam sts ­ u initial co unldaitt io io nnswatso st easrttiemdatwe ith th e s lig mha tl gynid tu if dfee ren otfvhaalviedah te addahisnkdic ll asstismim lar adteotwhiatthotbhtea in seadme fr osm ta t c is rto ic sasl -v av anrp ia re ti doincs ta ble and therefore random atmospheric methods. The chief limitation to further progress is a rai enrfaag ll edf or tion th ca elcm ul oad te e l. thTehebtehsitr te meondseilmeus la ti t m io antseao re flsaecaksoonf ( gJluonbeal th tr roopu ic gahlSSeSpTtefm or beecra ) s . tsAvcaclu id ra f te orfo th re ecawse ts ttgylpoibcaall ly v , a a ri l th ea ocuhghgitvheen seasonal SST pattern. Quite of ENSO would help, but would in most years be well, it sho at w io ends in sem as oodneall re ra piln ic fa altledpa th tt eeronbs se qruvietdeifn al sluffo fi rceiceanst. tsAatrmeoaslp so heu ri scedd , ynbaumtitchaely -m oondleyl -h baavseedusreaf in ul ­ T re hgu io s ns fo rofptrheec ip w it s a ystematic or tlido , n -t rhee la tmesdpaa ti pap ll l y ic var odel pre a d ti i o ct nys in g in biases. skill with lead times of a month or less before the require some kind ions wmoaun ld y r th ai antf al hlusm ea asnoin ty ( Fhoa ll sanidncerteaals . ed1 99 th 1 e ). Istuisscaelpsto ib p il o it s y si b o le f g ki ennderoaf te bdi as byadajuM stm OS ofteacdhjnuisqtumee . n T ts h , e perhaps those tropical west Africa to drought through the pro­ production of operat einot places a huge bnue rd ed en foorntthhiesg co re vsesrivoevreerdu re c c ti eonntd in ecnaedaers -. coTahsitsalcw ha e n st geAfirn ic a th nefolraensdtM because each time the m na oldd el y n is a m ch ic aanlge fo d r , eacansetwmsoedteo ls f s (e u . r g fa ., ceElb ta ohuinrdaan ry dhGaosnbgee1n99s6 ho ) w to nhbayve se v th e e ra lpo au te tnhtoirasla ne O ed S e statistics must be calculated to provide the to weaken the north African monsoon. More studies nneacleys si d sa s ad ojfu ry Msm tm u e lt n id ts e . c T ad h a is l re en qu se ir m es bltehsetgoe ne orbatta io in natnhdetorfopp ic oasls ib nloer th re g A io fr n ic aalnarnatihnrfo al p l, ogaesniwce ll inafs lu efnocr es on fundamental OiSmp st rao ti vse ti m cs enatnsdtuond th eerssecom re osdtehles , nseuecdh fo as r reg W ion ar sdwe it thaml. a ( r 1 gi 9n9a3l ) seaalssoonadlisrcau in sfsaltlh , e a re sk n il eleo de odt . her tahboosvee . related to the flux adjustments, discussed m tim ad eefboy re c th a e st sff real­ UK orM th et eeon ro olro th g e ic aasltOBfrfaizcielsw in ectes1e9 as 8o7n . dro Kungohwt le p d re gdeico ti fonEsNS in O m is a n in ysup ff airctisenotffotrher eg w io o n rl adlT se hviesreisa relatively dry area, subject to intermittent lbeescsaium se p o in rt a th n ese regions its influence is either small or Hastenr dartohuagnhdt. c T ol hleasbeorfao to re rs c a ( set . s g , ., asHw as etlelnarsatthho1s9e95b ) y , p ea ro st foBurnad zil an t than other factors. For instance, north­ are mainly statistical, although real-time dynamical patterns ( lFyo ll iandf lu west A nd eentcael. d frican w 19 b9y1 , H tro ept ic saela so Ant la ra nitn ic fa ll astenrath 1995, WSaSrTeM for eetceaosrtosl og hiacvae ard based on tropi lcbaOlAfefe ic n e . mTahdee st saitn is ctei cal 19f9o4 re ca bsy ts tahreeS1S9T 97 ) i . n In th aeddtirtoipoinc , aplaIrn ts d i of the Sahel are affected by on ENSO SSTs. On tl aanv ti ecraSgSeT , t a ro npoim ca allyAp tl aatn te ti rcnsSaSnTdsF Si o m ll i a la nrd ly , eltocaall . SS 19 T9p1a , tt Bar anns to Onceaannd (P Sam lm ith er11999866 ). , h re agvieonaboofuSt ou tw th ic Aem th e e ri cian , fl aule th nocue gh ofexEtN re SmOeE fo NrStOhs is , A no urstth ra w li eas , tnooftA ab ulsyt ra ilniatih er e ns influence precipitation in such as that in 1982-3, can dominate the circulation Drosdowsky 1993, F n re d th IendA ia uns tr O al c ia enanw north and and precipitation patterns over tropical South ericksen and i B nt aelrgo ( v e. ign . d , A sis m te e n ri t c ly a . h T ig hhe le r v ea el l -t o im f e sk iflol, resc im as itlsarhtaovethhaatdobatac in oend ­". En Droughts, 63. Routledge, 2016. http://dx.doi.org/10.4324/9781315830896-43.

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Actas de conferencias sobre el tema "Isotopes Li et Nd"

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Johansson, Sveneric, Ulf Litzén, Jörg Kasten y Manfred Kock. "Isotope Shift in B I at 2090 Å as a Probe of Cosmic Nucleosynthesis". En High Resolution Fourier Transform Spectroscopy. Washington, D.C.: Optica Publishing Group, 1992. http://dx.doi.org/10.1364/hrfts.1992.thd4.

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Determination of the cosmic abundance of the light elements Li, Be and B is critical for the understanding of how these elements have been formed in the Universe. The Standard Model for the Big Bang nucleosynthesis, which assumes a uniform density, and its complementary model, the Non-uniform Density Model (see e.g. Kajino and Boyd, 1990), differ considerably in their predictions of Be- and B-production . However, recent determinations of the abundance of Be (Gilmore et al. 1991) and B (Duncan et al. 1992) in metal-poor stars are orders of magnitude larger than those predicted from any Big Bang nucleosynthesis model. The isotopes 9Be, 10B and 11B are therefore thought to have been produced by cosmic spallation, primarily when high-energy protons and α-particles collide with CNO nuclei in the interstellar medium.
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Lloyd-Mills, Frank, Jingyi Cheng, Meng Wang y Wenfeng Li. "Geomechanical Characterization of Natural Shale-Sandstone Interface". En 57th U.S. Rock Mechanics/Geomechanics Symposium. ARMA, 2023. http://dx.doi.org/10.56952/arma-2023-0309.

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ABSTRACT Understanding the strength of rock discontinuities has been one of the core research topics in geomechanics over the past decades. This is unsurprising as many structural failures in underground excavations, including mining and tunnelling, occur at rock discontinuities. In oil, gas, and geothermal industry, the strength of rock discontinuities has also attracted a great deal of attentions because, for example, pre-existing discontinuities can significantly change the structures of hydraulic fracture networks. It is also anticipated that the strength of rock discontinuities will become increasingly important for leakage risk assessment of carbon dioxide geological sequestration projects. For all these reasons, we must achieve a good understanding of strength of natural rock discontinuities at the subsurface stress conditions, which, unfortunately, is not well explored. This problem can be primarily attributed to the limited numbers of valid rock samples that contain natural and undisturbed rock discontinuities, especially for the case of cohesive rock discontinuities. In this study, we obtained some rock specimens with naturally bonded shale-sandstone interface. We measured the geomechanical properties of the natural shale-sandstone interface under constant normal loads, using biaxial direct shear apparatus. The measured strength of interface indicates the combined effect of normal loading levels and natural interface roughness. Our characterization provides valuable geomechanical data of natural shale-sandstone interface at the subsurface conditions. These data can benefit all subsurface engineering projects where it is crucial to examine shale-sandstone interface failure for project success, including underground mining, tunnelling, fluid injection/extraction in sandstone reservoirs of shale caprocks. INTRODUCTION Geomechanical properties of rock discontinuities are of great importance in many underground engineering projects. In mining engineering, rock discontinuities often govern deformation and failure of rock masses surrounding underground openings, such as the occurrence of coal bumps due to lost of constraint at coal-rock interface (Li et al., 2015a and 2015b). In oil and gas engineering, rock discontinuities are the primary fluid flow pathways in tight formations and can also greatly influence the wellbore stability and hydraulic fracture structures (Karatela et al., 2016; Li et al., 2021a and 2021b; Li et al., 2022; Meng et al., 2021a and 2021b; Welch et al., 2021). In enhanced geothermal system (EGS), rock discontinuities govern the hydrofracking and hydroshearing process and contribute significantly to the stimulated rock volume for effective fluid flow and heat mining (Rinaldi and Rutqvist, 2019; Bijay and Ghazanfari, 2021; Meng et al., 2022). In carbon sequestration projects, rock discontinuities can cause CO2 leakage under rock stress or fluid pressure perturbation (Carey et al., 2009; Pan et al., 2013; Frash et al., 2017). In nuclear waste disposal or underground nuclear explosion detection, rock discontinuities can facilitate transport of the radionuclide gas isotopes from the cavity to the surface (Zhang et al., 2022). It is anticipated that in carbon mineralization projects, rock discontinuities can greatly affect project success because mineral dissolution and solid mineral molar precipitation can either promote or kill the long-term fracture permeability due to the coupled thermos-hydro-mechanical-chemical (THMC) processes (xiong et al., 2017; Menefee et al., 2018). For all those reasons, it is imperative to study the geomechanical properties of rock discontinuities for effective utilization of subsurface resources.
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