Isotopic tracers

Environmental DNA (eDNA) has revolutionized ecological research, particularly for biodiversity assessment in various environments, most notably aquatic media. Environmental DNA analysis allows for non-invasive and rapid species detection across multiple taxonomic groups within a single sample, making it especially useful for identifying rare or invasive species. Due to dynamic hydrological processes, eDNA samples from running waters may represent biodiversity from broad contributing areas, which is convenient from a biomonitoring Dawn R. URycki and Anish A. Kirtane are co-lead authors and contributed equal effort.

This article offers a comprehensive survey of figurative finds from Neolithic northern Europe. The survey shows that the immediate absence of figurative representation in the region is real and that the almost complete lack of figuration stands out from the previous Mesolithic and the contemporary northern and northeastern European Neolithic hunter-gatherer groups. Furthermore, the absence of figurative representations contrasts strongly with the thousands of clay figurines that characterize the southeastern European and Anatolian Neolithic. The survey provides a welldocumented basis for discussing the significant differences between a figurative southeastern European Neolithic and an imageless northwestern European Neolithic. We suggest that the absence of figurative representations indicates that severe sociocultural and religious/ideological changes took place within the Neolithic communities as agriculture spread from southeastern Europe via central Europe to northern and western Europe.

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parts of the field investigations. The PhD thesis comprises a synopsis of the work presented in two published papers, two manuscripts prepared for scientific journals and a technical note. In the synopsis of the thesis the papers are referred to by the names of the authors and the Roman numerals (e.g. Damgaard et al., III). The papers included in the thesis are:

Археологический микрорайон в среднем течении р. Синташта был выделен на основании анализа пространственного распределения археологических памятников эпохи бронзы. Он имеет протяженность 31 км и включает в себя 12 поселений позднего бронзового века, в том числе два укрепленных поселения; а также 10 погребальных памятников, в составе которых зафиксировано 105 курганов, и менгиры, расположенные на окраине двух поселений. Большинство поселений располагаются на надпойменной террасе на левом, более рельефном берегу реки, где проще было найти площадки надпойменной террасы, прикрытые с севера холмами от ветра. Менгиры обнаружены на площадках поселений несколько выше жилищных впадин, а курганные могильники – по обоим берегам реки, выше поселений, у тылового шва надпойменной террасы либо на склонах и невысоких площадках коренного берега. Памятники микрорайона отражают хозяйственную и ритуальную деятельность скотоводов и металлургов эпохи поздней бронзы. Его возникновение связано с укрепленными поселениями синташтинской культуры; развитие – с наиболее многочисленными здесь неукрепленными поселениями алакульской культуры, на позднем этапе существования в составе которых появляется алакульско-федоровский и черкаскульский культурные компоненты. Спад численности населения отмечен в период расселения на остатках алакульских поселений населения межовской культуры. Памятников переходного периода от эпохи бронзы к раннему железному веку на территории микрорайона не обнаружено.

Recent strontium isotope (87 Sr/ 86 Sr) analyses of bones and teeth have provided useful archeological results for reconstructing past human migration and diet. We report 87 Sr/ 86 Sr ratios and DNA analyses of tooth enamel from individuals buried in some necropolises in Nola town, near Napoli (Campania, South Italy). These individuals lived in the period between the Avellino (1925 years BCE) and CE 472 Pollena Vesuvian eruptions and are dated on archeological basis to the time span between the sixth and second century BCE. Tooth enamel 87 Sr/ 86 Sr ratios (0.70788-0.70864) are higher than baseline values in the necropolises (0.70756-0.70792): this can be explained by assuming either that all the analyzed individuals are not local-an unlikely possibility-or that they ate both local and foreign food (within about 50 km), including 87 Sr-rich seafood. An explanation for such a varied diet might be that the individuals from Nola were living near the Ancient Appia and Popilia ways and not far from the coastline. Whatever its origin, the 87 Sr/ 86 Sr ratios represent the isotopic signature of the local community living on the slopes of Mt. Somma-Vesuvius between the sixth and second centuries BCE. This knowledge will support future isotope studies on volcanic eruptions as possible causes of human migration. Keywords Tooth enamel Sr isotopes. Human migration. Mt. Somma-Vesuvius. Buried individuals. Necropolises of Nola Short highlights • We analyzed 87 Sr/ 86 Sr on teeth and bones from individuals buried in Nola, South Italy. • We determined the sex of the humans from Nola necropolises. • 87 Sr/ 86 Sr ranges from 0.7079 to 0.7086 for tooth enamel. • 87 Sr/ 86 Sr ranges from 0.7075 to 0.7085 for the local baseline. • This is the first attempt to study people mobility in Campania through 87 Sr/ 86 Sr.

Mobility of people and goods during the Upper Paleolithic has proven difficult to reconstruct given the relative rareness of remains. Nevertheless, archaeological contexts like the Late Pleistocene horizon of Borsuka Cave (Southern Poland) represent a unique opportunity to explore patterns of objects’ transportation across Central Europe. We investigated the origin of four ornaments made of European elk (Alces alces L.) incisors recovered at Borsuka Cave – the oldest known burial site in Poland, possibly a child grave. Laser-ablation plasma source mass spectrometric analyses of trace elements and Sr isotopic compositions revealed that one elk was roaming within a geologically uniform area while the others changed their pastures during their lifetimes. The non-local origin of the elk teeth is inferred from their exotic Sr isotopic compositions and the lack of evidence for the presence of elk in this territory during the Pleistocene. Instead, the elks’ Sr isotopic composition show goo...

Nuclear charge radius differences in the silver isotopic chain have been reported through different combinations of experiment and theory, exhibiting a tension of two combined standard errors. This study investigates this issue by combining high-accuracy calculations for six low-lying states of atomic silver with an improved measurement of the 5s 2 S 1/2 − 5p 2 P 3/2 transition optical isotope shift. Our calculations predict measured electronic transition energies in Ag I at the 0.3% level, the highest accuracy achieved in this system so far. We calculate electronic isotope shift factors by employing analytical response relativistic coupled-cluster theory and find that a consistent charge radius difference between 107,109 Ag is returned when combining our calculations with the available optical isotope shift measurements. We therefore recommend an improved value for the mean-squared charge radius difference between 107 Ag and 109 Ag as 0.207(6) fm 2 , within one combined error from the value derived from muonic Ag experiments, and an updated set of charge radii differences across the isotopic chain.

Water and manure management from industrial poultry and swine farms in Yucatan, Mexico are driving socioenvironmental conflicts due to policies that largely ignore the karstic landscape's limited capacity to recycle manure nutrients and prevent pollution of groundwater, the only freshwater source in the region. Mexico's trade favors access to export markets and conditions for rapid industrial farm expansion. Analysis of secondary information on industrial swine and poultry production in 21 municipalities generated 11,553 metric tons of excreted nitrogen in 2020. An open, evidence-based debate among stakeholders is needed on water and manure management policies to ensure sustainability and equity.

Optimizing empirical baseflow filters using environmental tracers (e.g., specific electrical conductance (SEC), turbidity) is an effective and efficient way to quantify the contribution of baseflow to total flow. To execute this baseflow separation, three key components are needed: The tracer, the method to estimate tracer concentration in different flow components, and the empirical baseflow filter. However, a comprehensive evaluation of the various combinations of these components, especially with a large sample of catchments, is currently lacking in the literature. Therefore, our study assembles 16 hybrid baseflow filters from two tracers, two concentration estimation methods, and four empirical baseflow filters, and evaluated their performance in baseflow separation and producing two long-term baseflow signatures for 1,100 catchments in the Contiguous United States. Our results suggest that SEC is a superior tracer to turbidity for baseflow separation. Additionally, using monthly maximum and minimum values to represent tracer concentration in flow components produces better separation than using a power function relationship between flow rate and concentration. The four empirical baseflow filters offer a similar level of performance, regardless of the other options used. Yet, some of these filters produce inconsistent results in calculating the baseflow signatures for the catchments. Our analysis shed light on the optimization of hybrid baseflow filters for the accurate quantification of baseflow contribution. Plain Language Summary River flow can be broken down into two components: fast flow and slow flow. The latter is usually known as baseflow, and it represents the stable portion of river flow that comes from stored water sources, such as groundwater or snowpack. It is crucial to understand the proportion of baseflow in river flow for effective water resource management. A commonly used method to separate baseflow from river flow is by filtering streamflow data with empirical baseflow filters. These filters contain some parameters that are often optimized using geochemical data, such as specific electrical conductance (SEC) and turbidity, to ensure reasonable performance of baseflow separation. This study examined how SEC and turbidity can be used to optimize four empirical baseflow filters for quantitative assessment of baseflow contribution to streamflow. Our analysis of 1,100 catchments across the Contiguous United States revealed that SEC is a more reliable indicator of baseflow than turbidity. Interestingly, the choice of empirical baseflow filter had minimal impact, though some filters produced inconsistent results for the quantification of baseflow contribution. This research enhances our ability to accurately estimate baseflow, aiding in water resource planning and management.

Northeastern Tunisia is a sub-humid region with annual rainfall ranging from 600 to 650 mm. Unconfined groundwater in this area is easily accessible and represents an important perennial water source for agricultural activities. The present study deals with a multi-parameter investigation of one of the most important basins in northeastern Tunisia: the Wadi Guenniche plain (130 km 2). Hydrochemical (major elements and Br −) and isotopic (18 O, 2 H and 3 H) investigations were carried out on 32 shallow wells to gain insights into groundwater recharge and salinity. The dominant water types were Ca-Mg/Cl-SO 4 and Na/Cl with electric conductivity values varying between 0.86 and 6.6 mS/cm. Based on ion ratios and saturation indexes, groundwater salinity originated from weathering of carbonate and evaporite minerals and cation-exchange with clays. Additional influence of anthropogenic activities shown by high NO 3 − concentrations exceeding 100 mg/L was identified in different parts of the plain resulting from irrigation return flow. A six-year record of 18 O and 2 H signatures of daily rainwater (n = 293) enabled to define a Local Meteoric Water Line for the Bizerte area (δ 2 H = 7.02 δ 18 O + 8.27). The isotopic signature of groundwater was very similar to that of the mean annual rainfall in Bizerte suggesting direct recharge of the aquifer. Tritium levels in sampled wells were relatively high and indicated recent recharge and short residence time. Annual recharge of 100 mm was estimated using a mixing model based on 3 H contents in precipitation and groundwater.

The full range of our publications is available from BGS shops at Nottingham, Edinburgh, London and Cardiff (Welsh publications only) see contact details below or shop online at www.geologyshop.com The London Information Office also maintains a reference collection of BGS publications including maps for consultation. The Survey publishes an annual catalogue of its maps and other publications; this catalogue is available from any of the BGS Sales Desks. The British Geological Survey carries out the geological survey of Great Britain and Northern Ireland (the latter as an agency service for the government of Northern Ireland), and of the surrounding continental shelf, as well as its basic research projects. It also undertakes programmes of British technical aid in geology in developing countries as arranged by the Department for International Development and other agencies. The British Geological Survey is a component body of the Natural Environment Research Council.

Modélisation clinique et biochimique de l'insuffisance intestinale chronique chez l'homme. La concentration plasmatique veineuse post-absorptive de citrulline, marqueur de la masse entérocytaire absorptive. L'insuffisance intestinale chronique résulte le plus souvent d'une malabsorption nécessitant une nutrition parentérale pour maintenir l'équilibre nutritionnel. Sa cause habituelle est le syndrome de grêle court (SGC). Dans ce dernier (n=124) nous avons déterminé par analyse actuarielle multidimensionnelle les facteurs de dépendance à la nutrition parentérale et de survie. Nous avons ainsi discriminé l'insuffisance intestinale transitoire et permanente par les césures de longueur de grêle selon le type anatomique et de période adaptative post-résection (2 ans). Notre objectif a ensuite été de déterminer, dans l'insuffisance intestinale, un marqueur biologique de la masse entérocytaire absorptive. Après avoir optimisé chez l'homme sain l'administration digestive des traceurs isotopiques du métabolisme protéique (leucine, glutamine) en démontrant que seule la perfusion duodénale, par rapport à la perfusion gastrique, permettait d'obtenir des résultats reproductibles pour l'état stationnaire et l'extraction splanchnique, nous avons fait l'hypothèse que la citrullinémie, acide aminé non protéique produit du métabolisme entérocytaire de la glutamine, pouvait être un marqueur candidat. En préalable, dans le SGC, nous avons validé une méthode radiologique pour évaluer anatomiquement la masse intestinale et modélisé la masse intestinale fonctionnelle grâce aux bilans d'absorption. Nous avons montré que l'hyperphagie était l'un des facteurs majeurs qui caractérisait ces patients (présente chez 82%) et qu'elle participait à l'expression de l'adaptation intestinale. Nous avons alors, dans le SGC (n=57), pu démontrer que la citrullinémie est un marqueur de la masse entérocytaire du fait : a) de son abaissement par rapport aux contrôles, b) de sa corrélation positive (r=0.83, P<0.0001) avec la longueur de grêle, c) de sa liaison avec les coefficients d'absorption, d) de son pouvoir discriminant pour le type et la sévérité de l'insuffisance intestinale. Nous avons confirmé notre hypothèse en montrant dans un 2 ème type d'insuffisance intestinale potentielle, le syndrome d'atrophie villositaire (n=52 dont 42 maladies coeliaques), que la citrullinémie indiquait l'intensité et l'étendue des lésions sur l'intestin grêle. Par contre dans la pseudo-obstruction intestinale chronique (n=6), la citrullinémie est (sauf en cas de lésions histologiques intestinales) subnormale. Nous avons vérifié que la dénutrition pure (marasme par anorexie mentale restrictive, n=57) n'influençait pas la citrullinémie. L'évolution et la normalisation de la citrullinémie après transplantation intestinale pour insuffisance intestinale permanente nous a confirmé que, in vivo chez l'homme, la citrullinémie est bien d'origine grêlique. Ainsi la citrullinémie veineuse post-absorptive peut être utilisée comme marqueur de la masse entérocytaire absorptive. Discipline : Physiologie et Physiopathologie de la Nutrition Humaine Mots-clés : citrulline, insuffisance intestinale, nutrition parentérale, syndrome de grêle court, atrophie villositaire, absorption intestinale, transit baryté du grêle, traceurs isotopiques, transplantation intestinale. Cette thèse n'aurait pu voir le jour sans la contribution de nombreuses personnes et organismes que je tiens à citer ici : Le professeur Bernard Messing, qui nous a guidé dans nos travaux, et dont l'exigence n'a d'égard que le niveau élevé de compétence Le docteur François Thuillier, pour son soutien Le docteur Dominique Darmaun, pour ses judicieux conseils Madame Marie-Christine Morin, pour sa grande expérience dans le recueil et l'analyse des enquêtes diététiques Le professeur Luc Cynober et le docteur Colette Coudray-Lucas, pour leur expertise dans l'analyse des acides aminés plasmatiques Le professeur Claude Matuchansky, pour sa rigueur et sa grande culture dans le domaine des pathologies intestinales Le docteur Marie-Christine Boutron, pour ses précieux conseils concernant l'analyse statistique Le professeur Michel Mignon, pour m'avoir reçu dans son service d'Hépato-Gastroentérologie et Nutrition de l'hôpital Bichat, ce qui m'a permis de compléter ma formation Le professeur Daniel Rigaud, pour m'avoir initié dans certains domaines physiologiques et fait entrevoir la complexité des troubles du comportement alimentaire M. J. Arsham pour son importante contribution à la syntaxe anglo-saxonne L'unité INSERM U290 (Hôpital Saint-Lazare, Paris), où une partie de ce travail a eut lieu L'ESPEN (European Society of Enteral and Parenteral Nutrition Society), pour son soutien matériel (ESPEN-Fellowship 1995) à la réalisation d'une partie des travaux présentés dans cette thèse L'ensemble des malades en situation d'insuffisance intestinale ayant participé aux travaux présentés, ainsi que leurs soignants, en sachant combien le vécu et la prise en charge quotidienne de cette situation est difficile Et bien d'autres qui, peu ou prou, à travers notamment de nombreux échanges, ont également contribué à l'élaboration de ce travail. Je m'en voudrais enfin de ne pas citer Camille, qui a du endurer les mois de préparation de ce manuscript. Listes des travaux personnels réunis dans la thèse Article 1: Long-term survival and parenteral nutrition dependence in adult patients with the short bowel

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& Key message Fluxes of base cations were studied in an Oriental beech forest and an adjacent forest gap. The fluxes of base cations in throughfall, litterflow, topsoil and subsoil solution were higher in a mixed Oriental beech forest compared to the fluxes in rainfall and topsoil and subsoil solution in the forest gap. A large proportion of cations were adsorbed or biologically immobilised by passing through the litter layer in the forest. In the mineral topsoil, a new equilibrium between the solid phase and soil solution was established where desorption/leaching surpassed adsorption/immobilisation for Ca 2+ and Mg 2+ while the opposite was true for K +. The contribution of throughfall is considerable in biogeochemical cycling. & Context Although it is important to measure nutrient fluxes to establish forest soil chemical fertility, little data is available for Oriental beech forests, one of the most important commercial hardwood forests in Iran. The quantification of nutrient fluxes above and below ground is essential because nutrients in the soil solution are most easily available for tree uptake. A thorough understanding of biogeochemical nutrient cycling requires an investigation of nutrient fluxes between different compartments. & Aims We evaluated the effect of Oriental beech forests on biogeochemical cycling of Ca 2+ , Mg 2+ , K + and Na + by analysing their fluxes in rainfall, throughfall, litterflow and soil solution. & Methods Throughfall, litterflow and soil solution were sampled during one whole year under five Oriental beech trees in a mixed Hyrcanian beech forest. The amounts of Ca 2+ , Mg 2+ , K + and Na + in these fluxes were calculated based on their concentrations and the sampled volumes and subsequently compared with the respective fluxes in the rainfall and soil solution of an adjacent forest gap. & Results We found significantly higher fluxes in all the measured base cations in throughfall compared to rainfall. Entering the litter layer in the forest, nearly 50% of the dissolved base cations adsorb to the solid phase or are biologically immobilised prohibiting their leaching to deeper soil horizons. In the mineral soil, the interactions between the solid phase and soil solution were comparable between the forest and the forest gap. & Conclusion This study highlights the role of interactions of rainwater with tree crowns and the litter layer in biogeochemical cycling and emphasises its importance for the maintenance of soil chemical fertility in Oriental beech forests.

& Key message Fluxes of base cations were studied in an Oriental beech forest and an adjacent forest gap. The fluxes of base cations in throughfall, litterflow, topsoil and subsoil solution were higher in a mixed Oriental beech forest compared to the fluxes in rainfall and topsoil and subsoil solution in the forest gap. A large proportion of cations were adsorbed or biologically immobilised by passing through the litter layer in the forest. In the mineral topsoil, a new equilibrium between the solid phase and soil solution was established where desorption/leaching surpassed adsorption/immobilisation for Ca 2+ and Mg 2+ while the opposite was true for K +. The contribution of throughfall is considerable in biogeochemical cycling. & Context Although it is important to measure nutrient fluxes to establish forest soil chemical fertility, little data is available for Oriental beech forests, one of the most important commercial hardwood forests in Iran. The quantification of nutrient fluxes above and below ground is essential because nutrients in the soil solution are most easily available for tree uptake. A thorough understanding of biogeochemical nutrient cycling requires an investigation of nutrient fluxes between different compartments. & Aims We evaluated the effect of Oriental beech forests on biogeochemical cycling of Ca 2+ , Mg 2+ , K + and Na + by analysing their fluxes in rainfall, throughfall, litterflow and soil solution. & Methods Throughfall, litterflow and soil solution were sampled during one whole year under five Oriental beech trees in a mixed Hyrcanian beech forest. The amounts of Ca 2+ , Mg 2+ , K + and Na + in these fluxes were calculated based on their concentrations and the sampled volumes and subsequently compared with the respective fluxes in the rainfall and soil solution of an adjacent forest gap. & Results We found significantly higher fluxes in all the measured base cations in throughfall compared to rainfall. Entering the litter layer in the forest, nearly 50% of the dissolved base cations adsorb to the solid phase or are biologically immobilised prohibiting their leaching to deeper soil horizons. In the mineral soil, the interactions between the solid phase and soil solution were comparable between the forest and the forest gap. & Conclusion This study highlights the role of interactions of rainwater with tree crowns and the litter layer in biogeochemical cycling and emphasises its importance for the maintenance of soil chemical fertility in Oriental beech forests.

MEDICIÓN Y CARACTERIZACIÓN DE LOS RESIDUOS SÓLIDOS UNIDADES DE ESTUDIO CARACTERIZACIÓN DE RESIDUOS CARACTERIZACIÓN Y EFICIENCIA DEL MANEJO DE RESIDUOS RESULTADOS DE LA OBSERVACIÓN SOBRE EL MANEJO DE LOS RESIDUOS SÓLIDOS EN LA UNSAAC GRADO DE INFLUENCIA DEL MANEJO DE RESIDUOS SOBRE EL IMPACTO AMBIENTAL IMPACTOS AMBIENTALES GENERADOS POR LA ACTIVIDAD DE MANEJO DE RESIDUOS EN LA UNSAAC. FORMULACIÓN DE LA MATRIZ DE IMPORTANCIA MATRIZ DE IMPORTANCIA: VALORACIÓN DE IMPACTOS AMBIENTALE

Post-collisional volcanism in northwestern Iran is represented by the Saray high-K rocks including leucite-bearing under-saturated and leucite-free silica saturated rocks. We report Ar-Ar age data which constrain the age as ca. 11Ma (late Miocene). Most of clinopyroxene phenocrysts from the volcanic rocks have complex oscillatory zoning, with high Ti and Al cores, low Ti and high Al mantled clinopyroxenes, grading into low Ti and Al outer rims. All the rocks are highly enriched in incompatible trace elements and have identical Sr-Nd-Pb isotopes. Enrichment in incompatible elements and other geochemical features for the Saray lavas suggest a metasomatized sub-continental lithospheric mantle (SCLM) as the magma source. The negative Nb-Ta-Ti anomalies for the Saray lavas compare with the features of subductionrelated magmatism with negligible contamination with ancient crustal components. The highly radiogenic 87 Sr/ 86 Sr and 207 Pb/ 204 Pb isotopic values of the Saray lavas imply the involvement of slab terrigenous sediments and/or a continental lithosphere. Isotopically, the volcanic rocks define a binary trend, representing 5-8% mixing between the primary mantle and sediment melts. Our melting models suggest residual garnet in the source and are incompatible with partial melting of amphibole and/or phlogopite bearing lherzolites, although the complex geochemical features might indicate the result of mixing between melts produced by different sources or a homogenous melt passing through a compositionally-zoned mantle during multiple stages of partial melting and melt migration. The geochronological, geochemical and isotopic data for the Saray rocks suggest that these Late Miocene magmas were derived from a small degree of partial melting of subduction-metasomatized (subcontinental) lithospheric mantle source in a post-collisional setting.

Stable isotope ratios of major elements can be used to infer much about local-and global-scale processes on a planet. On Titan, aerosol production is a significant sink of carbon and nitrogen in the atmosphere, and isotopic fractionation of these elements may be introduced during the advanced organic chemistry that leads to the condensed phase products. Here we report on the isotopic composition of analogs of Titan's organic aerosol generated in the laboratory via photochemistry of CH 4 and N 2 gas mixtures.

Introduction. Le bilan lipidique correspond à un ensemble d’analyses permettant de mettre en évidence des anomalies du métabolisme des lipides et d’optimiser la prise en charge diététique et/ou le besoin thérapeutique pour le suivi, la surveillance et l’évaluation du risque athérogène. L’objectif de cette étude est d’évaluer la place du jeûne dans les recommandations pré analytiques du dosage des paramètres lipidiques. Matériels et Méthodes. Notre étude prospective a été réalisée sur 27 prélèvements sanguins sur tube hépariné, des patients en deux temps : à jeun et non à jeun après la prise d’un repas consistant. Le dosage des deux paramètres : Triglycérides et le Cholestérol total, ont été réalisé par la méthode colorimétrique enzymatique. Résultats. Nos résultats ont été classés en deux groupes pour chaque paramètre. L’étude statistique a été réalisée sur le logiciel Graph Pad Prism7. La comparaison des deux groupes TG par l’application du test non paramétrique de Wilcoxon retrouv...

Sabalan Volcano (NW Iran) is an isolated voluminous (4821 m elevation; >800 km 2) composite volcano that is located within the Arabia-Eurasia collision zone. Its edifice was assembled by recurrent eruptions of trachyandesite and dacite magma falling into a relatively restricted compositional range (56-67% SiO 2) with high-K calc-alkaline and adakitic trace element (Sr/Y) signatures. Previous K-Ar dating suggested protracted eruptive activity between 5.6 and 1.4 Ma, and a two stage evolution which resulted in the construction of the Paleo-and Neo-Sabalan edifices, respectively. The presence of a topographic moat surrounding Neo-Sabalan and volcanic breccias with locally intense hydrothermal alteration are indicative of intermittent caldera collapse of the central part of Paleo-Sabalan. Volcanic debris-flow and debris-avalanche deposits indicate earlier episodes of volcanic edifice collapse during the Paleo-Sabalan stage. In the Neo-Sabalan stage, three dacitic domes extruded to form the summits of Sabalan (Soltan, Heram, and Kasra). Ignimbrites and minor pumice fallout deposits are exposed in strongly dissected drainages that in part have breached the caldera depression. Lavas and pyroclastic rocks are varyingly porphyritic with Paleo-Sabalan rocks being trachyandesites carrying abundant phenocrysts (plagioclase + amphibole + pyroxene + biotite). The Neo-Sabalan rocks are slightly more evolved and include dacitic compositions with phenocrysts of plagioclase + amphibole ± alkali-feldspar ± quartz. All Sabalan rock types share a common accessory assemblage (oxides + apatite + zircon). High spatial resolution and sensitivity U-Pb geochronology using Secondary Ionization Mass Spectrometry yielded two clusters of zircon ages which range from 4.5 to 1.3 Ma and 545 to 149 ka, respectively (all ages are averages of multiple determinations per sample). U-Th zircon geochronology for selected Neo-Sabalan rocks agrees with the U-Pb ages, with the youngest zircon rims dating to ca. 110 ka. Because zircon 3 crystallization predates eruption, this age represents the upper limit for the youngest eruptions of Sabalan. Valley-filling ignimbrites yielded variable U-Pb zircon ages which argue against these pyroclastic rocks being generated in a single caldera forming event. These results indicate that eruptions occurred more recently than previously indicated by K-Ar dating. Paleo-Sabalan and Neo-Sabalan volcanic rocks have similar geochemical characteristics, including enrichment of LILE and LREE relative to HFSE and HREE, respectively, and prominent negative Ti, Nb, and Ta anomalies. The trachyandesitic to dacitic rocks of Sabalan also share negative Eu anomalies. This, together with horizontal or slightly increasing Y vs. Rb trends, indicates fractionation of plagioclase-amphibole or plagioclase-clinopyroxene assemblages with negligible crustal assimilation (based on low and invariant Rb/Th). High degrees of mantle partial melting are inferred from high (La/Yb) N (from 28 to 48). Overall, the subduction-affinity of Sabalan volcanic rocks agrees with models of melt generation following a Quaternary slab break-off event coeval with continental collision.

L’hypercalcémie et l’hyperphosphatémie postprandiales, ainsi que l’absorption intestinale du calcium (Ca), ont été mesurées chez 12 chamelons. Les animaux ont été divisés en quatre groupes de trois individus. Les groupes 1 et 2 ont reçu une perfusion intraveineuse (IV) respectivement du fragment synthétique du peptide apparenté à l’hormone parathyroïdienne (PTHrP) et du solvant. Au début de la perfusion, les groupes 1 et 2 ont reçu par voie orale du lait artificiel. Les groupes 3 et 4 ont reçu des injections IV respectivement de 1α,25-dihydroxyvitamine D3 (1α,25(OH)2D3) et du solvant. A la dernière injection, les groupes 3 et 4 ont reçu par voie orale une solution de SrCl2. Le PTHrP a induit une élévation significative de l’hypercalcémie et de l’hyperphosphatémie postprandiales. Ce peptide n’a influencé ni le volume urinaire, ni l’excrétion rénale du Ca, alors qu’il a provoqué une augmentation de l’excrétion rénale du phosphore (P). La 1α,25(OH)2D3 a engendré une augmentation signif...

Within the framework of the High Frequency Flux (HFF) experiment (MATER programme), time-series sediment traps have been deployed for two months on the continental slope off Marseilles to measure downward particle fluxes at a high frequency sampling rate (two and six days). Combined isotopic analyses of carbon and nitrogen have been performed on selected samples. Both isotopic tracers have been used for the first time on organic material of the Mediterranean Sea (Gulf of Lions) to determine the main biological sources and to address the biogeochemical processes that affected this material. Settling particles were characterised by very low values of δ 15 N (near 0‰) and δ 13 C (near-24.5‰) that indicate the existence of a mixed material with two sources that differ according to the considered element (C or N). The terrestrial source slightly dominates the carbon pool because of its higher C:N ratio, whereas the nitrogen pool may mostly originate from N 2-fixing cyanobacteria (δ 15 N. 0‰, low C:N ratio). These preliminary data suggest that dissolved atmospheric N 2 may act as a significant new nitrogen source in the Mediterranean Sea.

Spatial distribution of bioavailable strontium in the South Trans-Urals. Aim. Development and test of a methodology for obtaining a bioavailable strontium map suitable for studying migrations and mobility in the Bronze Age in the Southern Trans-Urals. Methods. Sampling was conducted in 73 loci located in a uniform network in a 25 ± 5 km grid and in 22 additional loci (transects along the intermediate lines in places of complex geological structure). The determination of strontium content was carried out by the ICP-MS method. The strontium isotope composition was measured using an inductively coupled plasma magneto-sector multi-collector mass spectrometer (MC-ICP-MS). Statistical methods included analysis with stem-and-leaf plots; Student’s t-test; ordinary kriging (the mean is unknown) with linear semivariogram; analysis of correlation according to Pearson’s test. Results. The surveyed area is 36 sq. km2. The sample size is 357. Samples for different types have similar mean and median values; the differences occur in the fourth fractional digit. Criterion 1 (n ≥ 0.001) can be used to determine local variability, and Criterion 2 (0.706 < n < 0.716) can be used to assess the origin of ancient individuals, animals, and archaeological objects. The interpolated maps for each sample type were created. All bioavailable strontium maps show similar spatial patterns. Cross-validation revealed areas of the lowest accuracy.
Conclusions. The similarity of the distribution of anomalies on the maps of different types suggests the feasibility of the sampling technique. There is a clear tendency for the zones of elevated 87Sr/86Sr values to be associated with the older lithology (0.7106, mean). The lower values (0.7091 ± 0.002) are associated with the younger lithology. Given the complex geological structure and a wide range of rocks in the study area, a positive result is the low differentiation of the zoning of
the identified anomalies, which correspond to large structural-formation zones of the Urals. The presented method demonstrates its suitability for studying sublatitudinal migrations of the ancient population of the Southern Trans-Urals.

A small and genetically isolated bottlenose dolphin (Tursiops truncatus) population that resides year-round in the Bocas del Toro Archipelago-Panama (BDT). Photoidentification and genetic data showed that this dolphin population is highly phylopatric and is formed exclusively by individuals of the "inshore form". This study aimed to investigate the trophic ecology and mercury concentrations of bottlenose dolphin in BDT to assess their coastal habits. We collected muscle samples (n=175) of 11 potential fish prey species, and skin samples from free-ranging dolphins in BDT (n=37) and La Guajira-Colombia (n=7) to compare isotopic niche width. Results showed that BDT dolphins have a coastal feeding habit, belong to the "inshore form" (δ 13 C=-13.05±1.89‰), and have low mercury concentrations (mean=1,637±1,387 ng g-1 dw). However, this element is biomagnified in the BDT food chain, showing a marginal dolphins health risk (RQ=1.00). These results call for preventive dolphin conservation measures and continue monitoring the pollutant levels.

Conclusion.-Notre étude a montré que l'atrophie musculaire peut être cachée par la masse grasse et donc non détectée par l'IMC. Cependant la CM, est un indice pouvant, de par sa simplicité, être un meilleur moyen de dépistage de ces atrophies lorsque l'impédancemétrie n'est pas accessible. P190 Interrelations between immunological parameters, nutrition, and health care-associated infections : prospective study in elderly in-patients

The concentrations of Co were determined in the hydrological cycle (in maquis and fir forests), litterfall and soils in maquis, oak, beech and fir forests. The concentrations in the hydrological cycle were characterized by high variability. The concentrations in soil solution were much higher than those in the bulk deposition and throughfall. The contribution of the earth's' crust in the bulk deposition enrichment with Co was not high but some minor quantities of Co can be considered to be transported in long distances. The concentrations of Co in litterfall were high in the fraction composed of lichens, flowers and mosses, especially in the fir forest. The total content of Co was significantly higher in the soils derived from mica schist than those in the flysch. The residence time of Co in the forest floor was rather long. This is an indication that weathering in the mineral layers plays an important role in providing Co for plant uptake.

Major and trace element and radiogenic and stable isotope data are reported for the Miocene Puesto La Peña undersaturated potassic complex, located in the Argentine Precordillera. The complex is composed of a pyroxenite core surrounded by a malignite-borolanite association, followed by radial and ring dikes composed of alkaline lamprophyres, tephrite to phonolite and intermediate varieties, porphyritic microledmorite, benmoreite, alkaline trachyte and a swarm of ultrabasic ouachitite dikes. Late trachytic to phonolitic volcanic necks and associated dikes crop out surrounding the malignitic-borolanitic massif. Major and trace element data are consistent with their derivation by partial melting from an enriched, probably lithospheric, metasomatized heterogeneous mantle involving spinel-and garnet-facies mantle sources. The trace element and isotope data indicate that all rock types are derived from a common parental magma and are thus cogenetic. Sr, Nd and Pb variations in the different studied lithologies are restricted, except for the evidence of Sr decoupling in the ouachitite samples. Their Sr-Nd isotope compositions follow the "mantle array" defined by oceanic basalts, within the OIB field, consistent with an intraplate depleted source. The genesis of the ouachitite is interpreted to be related to mixing between asthenospheric magma and melts from the lower lithosphere consisting of K-rich metasomatic layers. The Dupal like Pb isotopes signature suggests a mantle modification by introduction of continental crust material in the upper mantle; this is consistent with the Sr-Nd isotope data from the late silica-undersaturated felsic dikes and volcanic necks. Multistage mantle extraction would have occurred by the end of Neoproterozoic to lower Paleozoic times as indicated by the isotopic data. Partial melting was initiated by mantle upwelling decompression during lithosphere extension. Back-arc extensional conditions during the latest Early Miocene (19 Ma), related to the geometry of the Pacific subducted plate beneath the South American plate, favored the tectonic conditions for magma ascent from a magmatic reservoir located at around 30 km depth in the crust. A fractional crystallization process, primarily of clinopynoxene, plagioclase, alkali feldspar, nepheline and lesser biotite, magnetite, and apatite, first yielded the cumulate clinopyroxenite, followed by the malignite-borolanite association and the late dikes and volcanic necks. The morphology of the complex, as well as the relationship between their different facies, points to a cauldron subsidence model of emplacement.

Post-collisional volcanism in northwestern Iran is represented by the Saray high-K rocks including leucite-bearing under-saturated and leucite-free silica saturated rocks. We report Ar-Ar age data which constrain the age as ca. 11Ma (late Miocene). Most of clinopyroxene phenocrysts from the volcanic rocks have complex oscillatory zoning, with high Ti and Al cores, low Ti and high Al mantled clinopyroxenes, grading into low Ti and Al outer rims. All the rocks are highly enriched in incompatible trace elements and have identical Sr-Nd-Pb isotopes. Enrichment in incompatible elements and other geochemical features for the Saray lavas suggest a metasomatized sub-continental lithospheric mantle (SCLM) as the magma source. The negative Nb-Ta-Ti anomalies for the Saray lavas compare with the features of subductionrelated magmatism with negligible contamination with ancient crustal components. The highly radiogenic 87 Sr/ 86 Sr and 207 Pb/ 204 Pb isotopic values of the Saray lavas imply the involvement of slab terrigenous sediments and/or a continental lithosphere. Isotopically, the volcanic rocks define a binary trend, representing 5-8% mixing between the primary mantle and sediment melts. Our melting models suggest residual garnet in the source and are incompatible with partial melting of amphibole and/or phlogopite bearing lherzolites, although the complex geochemical features might indicate the result of mixing between melts produced by different sources or a homogenous melt passing through a compositionally-zoned mantle during multiple stages of partial melting and melt migration. The geochronological, geochemical and isotopic data for the Saray rocks suggest that these Late Miocene magmas were derived from a small degree of partial melting of subduction-metasomatized (subcontinental) lithospheric mantle source in a post-collisional setting.

Nutrition clinique et métabolisme 28 (2011) S67-S240 été observée. À la fin de la phase de suivi, dans le groupe de femmes qui ont continué à perdre du poids, cette relation entre acide myristoléïque et gènes de la lipogenèse de novo est également retrouvée. Conclusion.-Cette approche originale de biologie des systèmes apporte un regard nouveau sur la réponse du TA au contrôle pondéral, en soulignant le rôle central et inattendu de l'acide myristoléïque, qui pourrait être un déterminant de l'impact métabolique bénéfique de la perte de poids. La signature spécifique du TA des femmes reprenant du poids suggère au contraire une signature hyperplasique défavorable. P205 Mesure de l'abondance isotopique naturelle en 15N dans un modèle de restriction protéique chez la souris gestante

An in situ field demonstration was performed in fractured rock impacted with trichloroethene (TCE) and cis-1,2dichloroethene (DCE) to assess the impacts of contaminant rebound after removing dissolved contaminants within hydraulically conductive fractures. Using a bedrock well pair spaced 2.4 m apart, TCE and DCE were first flushed with water to create a decrease in dissolved contaminant concentrations. While hydraulically isolating the well pair from upgradient contaminant impacts, contaminant rebound then was observed between the well pair over 151 days. The magnitude, but not trend, of TCE rebound was reasonably described by a matrix backdiffusion screening model that employed an effective diffusion coefficient and first-order abiotic TCE dechlorination rate constant that was based on bench-scale testing. Furthermore, a shift in the TCE:DCE ratio and carbon isotopic enrichment was observed during the rebound, suggesting that both biotic and abiotic dechlorination were occurring within the rock matrix. The isotopic data and back-diffusion model together served as a convincing argument that matrix back-diffusion was the mechanism responsible for the observed contaminant rebound. Results of this field demonstration highlight the importance and applicability of rock matrix parameters determined at the bench-scale, and suggest that carbon isotopic enrichment can be used as a line of evidence for abiotic dechlorination within rock matrices.

Background & aims: Aging and experimental bed rest are associated with muscle atrophy and resistance to post-prandial stimulation of protein synthesis or anabolic resistance (AR). We have used in young and older adult volunteers, during short-term bed rest, a quick and non-invasive method, based on a single oral bolus of the stable isotope L[ring-2 H 5 ]phenylalanine (D 5 Phe), to determine post-prandial AR, defined as ratio between irreversible hydroxylation and incorporation into body protein of ingested phenylalanine. Methods: We compared in older (O, 59 ± 1 y) and young (Y, 23 ± 1 y) healthy male volunteers the effects of two-week bed rest on post-prandial protein kinetics, assessed during absorption of a standard readyto-use oral nutritional supplement, through stable-labeled isotope amino acid D 5 Phe, diluted in water, given as single oral load. The metabolic fate of D 5 Phe is either utilization for protein synthesis or irreversible hydroxylation to L[ring-2 H 4 ]tyrosine (D 4 Tyr). AR was defined as ratio between the areas under the curves of D 4 Tyr-to-D 5 Phe plasma concentrations over 6 h meal absorption. To determine the relationships between AR and muscle changes following bed rest, quadriceps muscle volume (QMV) was determined by magnetic resonance imaging (MRI). Results: At baseline, in pooled Y and O subjects, values of AR were inversely correlated with QMV (R ¼ À0.75; p < 0.03). Following 2-weeks of inactivity, there were significant bed rest effects on AR (p < 0.01) and QMV (p < 0.03), as well as significant bed rest  group interaction for AR (p < 0.03; þ9.2% in Y; þ21.9% in O) and QMV (p < 0.05; À5.7% in Y; À%7.3 in O). In pooled subjects, the percentage delta changes in AR and QMV, induced by bed rest, were inversely correlated (R ¼ À0.57; p < 0.05). Conclusion: Bed rest-induced AR is much greater in the older than in younger adults. We have developed a new, simple, non-invasive method for the assessment of AR. The results indicate that this metabolic abnormality is a key mechanism for sarcopenia of aging and inactivity.

Remediation of nitrate pollution of Earth’s rivers and aquifers is hampered by cumulative biogeochemical processes and nitrogen sources. Isotopes (δ15N, δ18O) help unravel spatiotemporal nitrogen(N)-cycling of aquatic nitrate (NO3−). We synthesized nitrate isotope data (n = ~5200) for global rivers and shallow aquifers for common patterns and processes. Rivers had lower median NO3− (0.3 ± 0.2 mg L−1, n = 2902) compared to aquifers (5.5 ± 5.1 mg L−1, n = 2291) and slightly lower δ15N values (+7.1 ± 3.8‰, n = 2902 vs +7.7 ± 4.5‰, n = 2291), but were indistinguishable in δ18O (+2.3 ± 6.2‰, n = 2790 vs +2.3 ± 5.4‰, n = 2235). The isotope composition of NO3− was correlated with water temperature revealing enhanced N-cascading in warmer climates. Seasonal analyses revealed higher δ15N and δ18O values in wintertime, suggesting waste-related N-source signals are better preserved in the cold seasons. Isotopic assays of nitrate biogeochemical transformations are key to understanding nitrate p...

One crucial task in groundwater research and management is the estimation of groundwater mixing ratios. Here, estimations of mixing ratios are presented systematically and spatially for shallow and deep groundwater in some areas of excessive groundwater pumping with different magnitudes of groundwater drawdown. The mixing ratios are estimated using two methods: (1) the total mixing ratio using all parameters, and (2) the mixing ratio using nitrate concentrations. The values for the total mixing ratio indicate that mixing between the shallow and the deep groundwater clearly occurs in all three depression areas, but with different ratios. The spatial distribution map of the total mixing ratio clearly shows that the largest mixing ratio occurs near the center of the cone of depression, and that the ratio decreases gradually away from the center of the depression area. There is a positive correlation among total mixing ratios, CFC-12 concentrations, and modeled vertical flux. Remarkably, the highest correlation is found between the correlation of the total mixing ratio and magnitude of vertical flux in the largest drawdown area. Meanwhile, comparison of the mixing ratio calculations by the different methods showed insignificant correlation which means nitrate is ineffective as the prevailing contaminant tracer for deep groundwater in this basin. Overall, this study concludes that the method of total mixing ratio using all chemical parameters is the most effective and consistent with previous methods. This study provides further proof that groundwater mixing between the shallow and deep groundwater systems has clearly occurred in the Bandung basin as an impact of excessive groundwater pumping.

New whole-rock and Sr^Nd isotopic analyses of Quaternary lavas from Kurdistan Province, western Iran, shed light on the nature of orogenic plateau magmatism during continental collision and the possible role of accessory minerals during mantle partial melting in this tectonic setting. The sampled lavas are from the TurkishÎ ranian plateau within the Arabia^Eurasia collision zone. Compositions are typically basanite, hawaiite and alkali basalt, with minor rhyolite. Most of the basic samples from the QorvehB ijar region have elevated abundances of large ion lithophile elements (LILE) and light rare earth elements (LREE) (e.g. 76 ppm5La5165 ppm), with steep REE patterns: 455La/ Yb5101. Two flows from Takab in the north of the study area have higher K 2 O/Na 2 O and Rb than the Qorveh^Bijar samples, but lower LREE and Ba. Sr^Nd isotope values for all the basic samples plot close to Bulk Silicate Earth, with 143 Nd/ 144 Nd between 0•51263 and 0•51276, and 87 Sr/ 86 Sr between 0•70467 and 0•70600; this is similar to Quaternary alkali basalts from the Iran^Turkey borderlands to the NW, but distinct from a more depleted source melting elsewhere in the same collision zone; for example, at Mount Ararat and the Kars plateau (Turkey). Crustal contamination does not appear to be an important factor affecting magma composition. The range of chemical signatures suggests variable melting of at least two distinct sources. One inferred source produced melts with La/Nb ranging from $3•5 to $1•2, which is unusual for volcanic rocks that are otherwise coeval. We interpret this variation as the result of depletion of a K-richterite-and rutile-bearing source during melting in the garnet stability field. The importance of this result is that the size of the negative Nb anomaly and fractionation of LILE may depend on K-richterite and rutile in the source mineralogy, rather than simply the bulk abundances of incompatible trace elements in the source region.We infer the presence of phlogopite in a second mantle source, the melting of which produced the more potassic lavas from Takab. Lithosphere delamination or slab break-off mechanisms for triggering melting are problematic in the study area, as the lithosphere is reportedly $150^200 km thick. Late Cenozoic extension has not been recognized, and so extension is unlikely as a cause of melting. The NW^SE alignment of volcanic centres, parallel to the regional structural grain, does imply a structural control, at least on the final eruption site. Eurasian mantle lithosphere was probably metasomatized by fluids derived from Mesozoic^early Cenozoic subduction and the early stages of collision. More recent convergence has had the potential to cause further fluxing and melting of the re-fertilized lithosphere, with rapid magma ascent assisted by transcurrent motion along the orogen. It is also possible that the negative dT/dP section of the amphibole peridotite solidus was crossed as a result of lithospheric thickening in the collision zone (i.e. compression melting rather than decompression melting). Exhaustion of accessory phases may also help explain larger-scale transitions from arc to within-plate chemistry in orogens, such as the Paleogene Arabia^Eurasia system, and the MesozoicĈ enozoic magmatism of eastern China.

Mobility of people and goods during the Upper Paleolithic has proven difficult to reconstruct given the relative rareness of remains. Nevertheless, archaeological contexts like the Late Pleistocene horizon of Borsuka Cave (Southern Poland) represent a unique opportunity to explore patterns of objects’ transportation across Central Europe. We investigated the origin of four ornaments made of European elk (Alces alces L.) incisors recovered at Borsuka Cave – the oldest known burial site in Poland, possibly a child grave. Laser-ablation plasma source mass spectrometric analyses of trace elements and Sr isotopic compositions revealed that one elk was roaming within a geologically uniform area while the others changed their pastures during their lifetimes. The non-local origin of the elk teeth is inferred from their exotic Sr isotopic compositions and the lack of evidence for the presence of elk in this territory during the Pleistocene. Instead, the elks’ Sr isotopic composition show goo...

Middle Miocene to Quaternary volcanic rocks cover large areas of the Azerbaijan Province in NW Iran. This study reports two separate age clusters out of 23 new LA-ICP-MS U-Pb zircon ages: (1) Middle Miocene (16.2-10.6 Ma) and (2) Latest Miocene-Late Pleistocene (5.5-0.4 Ma). Major and trace element bulk rock geochemistry and initial Sr, Nd, Pb radiogenic isotope data on the dated rocks provide new constraints on the Mid-Miocene to Quaternary volcanism in this region. The analyses are distributed over a large compositional range from low-K to high-K calc-alkaline andesites and dacites/rhyolites to more alkaline trachybasalts and dacites with shoshonitic affinities. Chondrite-normalized REE patterns are steep with significant enrichment in LREE and low abundances of HREE indicating a garnet control. Plots of primitive mantle-normalized trace elements show negative Ti and Nb-Ta anomalies indicative of an arc signature. The wide compositional range and the ubiquitous presence of an arc signature reveal that the source mantle is heterogeneous and metasomatically altered. Sr, Nd and Pb radiogenic isotope data further point towards an enriched mantle source and/or crustal contamination. Crustal contamination is best recognized by inherited zircon cores, which yield Late Neoproterozoic to Early Cambrian ages typical for the Iranian basement. The occurrence of adakite-like compositions with elevated magnesium numbers, Cr and Ni concentrations argue against a fractionation-driven process but point to a subcrustal origin. Overall, the analyzed lavas show no spatial and temporal relation to a potential subduction zone, confirming the dated volcanics to be post-collisional and not related to singular processes such as slab retreat or delamination of a continuous lower crustal sliver. We propose three hypotheses to explain the reported disparity in distribution, age and composition and favour small-scale sublithospheric convection or incorporation of crustal material into the metasomatized mantle. The discovery of the late Miocene time gap is in line with previously advocated exhumation pulses and coincides with a major tectonic reorganization in the Arabian-Eurasian realm at this time.

Using Cassini ion neutral mass spectrometer stable isotope observations, we have developed a comprehensive method for modeling the time-evolution of the stable isotopic ratios in Titan's major constituents, N 2 , CH 4 and H 2. Our model provides constraints on the initial 14 N/ 15 N ratio in N 2 , the time scale for the outgassing of methane from the interior, and the initial D/H ratio in methane. Over geologic time scales, the isotopes are fractionated by diffusion, atmospheric escape and photochemistry. Diffusion and escape preferentially remove the lighter isotopes for all constituents. Photolysis of methane also removes the lighter isotopes, while photolysis of nitrogen preferentially removes the heavier isotopes. We have found the following: (1) even taking past hydrodynamic escape into consideration, the initial 14 N/ 15 N ratio in N 2 cannot have changed much from its current value as the result of atmospheric processes. This is due to the large amount of N 2 that must be fractionated. Highrate loss processes, such as hydrodynamic escape, are inefficient fractionators and take a very long time to change the isotopic ratio. On the other hand, low-rate loss processes are efficient fractionators, but also take a very long time to influence a large inventory. (2) The current inventory of methane represents the remnant of methane that, constrained by the 12 C/ 13 C ratio, began outgassing from the interior more than 60 million years ago, resulting in a total inventory of 3-4 times the current inventory cycling through the system during this time period. Methane production is likely to be ongoing. (3) The initial D/H in methane was found to be 6.96-11.3 Â 10 À5 .

Sumaco Volcano is located in the rear-arc of Ecuador and produces phonolitic alkaline lavas hosting a unique assemblage of minerals including haüyne and titanaugite. The most mafic lavas are picrobasalts that contain titanaugite as the primary mineral phase; the most evolved tephri-phonolite lavas contain titanaugite + anorthoclase + haüyne. Titanaugite forms at middle to deep crustal pressures, whereas haüyne is only stable at shallow depths in highly oxidizing conditions. The Sumaco mineral assemblages and geochemistry indicate that fractionation of the titanaugite-and haüyne-bearing assemblage took place over a range of pressures from 5 to 25 kbar (14-75 km), with at least 50% of differentiation taking place at shallow crustal levels. Minerals record multiple cycles of recharge and mixing accompanied by an increase in fO 2 and sulfur concentration during differentiation. Mantle-like Sr and Nd isotope values (87 Sr/ 86 Sr = 0.70406-0.70423; 143 Nd/ 144 Nd = 0.512880-0.512913) indicate minimal crustal assimilation. Sumaco's unique geochemical composition is not observed in the nearby volcanoes Antisana, Pan de Azucar or El Reventador suggesting that its unique magma source is confined to this volcano. The high temperature and sulfate-saturated conditions at shallow depths suggest that magma ascends rapidly to a shallow reservoir where the majority of crystallization and recharge takes place prior to eruption. An important conclusion of this research is that Sumaco does not represent typical rear-arc subduction processes, and caution should be used when using Sumaco as an end-member to evaluate across-arc processes in the Northern Volcanic Zone.

Of the most abundant elemental constituents of organic matter, hydrogen has received the least attention due to its exchangeability with ambient water. The development of steam equilibration using two isotopically distinct waters can enable the user to calculate the proportion of exchangeable H and generate a δ 2 H value of the non-exchangeable H. Three fossil faunal assemblages from Europe were selected in order to investigate collagen δ 2 H with respect to body mass, diet and to compare chronological periods in the Quaternary. δ 15 N values in each suite of fauna show trophic level enrichment, a trend which was also observed in δ 2 H values. In the case of predatory species with lower δ 15 N values than other carnivore species, the use of hydrogen isotopes could help to infer the consumption of prey with lower δ 15 N values rather than a significant dietary contribution of plant foods. For example, a cave bear which exhibits low δ 2 H values are consistent with low δ 15 N and therefore point to an herbivorous diet and not omnivory. The combination of δ 2 H, with δ 15 N and δ 13 C, from archaeological and ecological studies of humans and fauna could help reconstruct prey preference; which is especially important when trying to distinguish the quantity of marine versus freshwater resources in diets. Relative to dietary influences, climate variability seems to be a minor control on δ 2 H in the faunal assemblages studied here. C