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| Registros recuperados: 29 | |
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| Bastos,Murilo Q. R; Souza,Sheila M. F. Mendonça de; Santos,Roberto V; Lima,Bárbara A. F; Santos,Ricardo V; Rodrigues-Carvalho,Claudia. |
| This study investigated strontium isotopes in the dental enamel of 32 human skeletons from Forte Marechal Luz sambaqui (shellmound), Santa Catarina, Brazil, aiming at identifying local and non-local individuals. The archeological site presents pot sherds in the uppermost archeological layers. Dental enamel was also examined from specimens of terrestrial fauna (87Sr/86Sr = 0. 71046 to 0. 71273) and marine fauna (87Sr/86Sr = 0. 70917). The 87Sr/86Sr isotope ratio for individuals classified as locals ranged from 0. 70905 to 0. 71064 and was closer to the isotope ratio of the seawater than to the ratio of the terrestrial fauna, indicating a strong influence of marine strontium on the inhabitants of this sambaqui. The results indicate the existence of three... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Brazil; Human mobility; Isotopes; Prehistory; Shellmounds; Strontium. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652011000200030 |
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| Thoby, Mary. |
| The redox conditions of the oceans evolved considerably during the Precambrian. This is mainly due to the arrival of the oxygen, at first generating oxygen oases, and then accumulating in the atmosphere during the Great Oxidation Event (GOE) ca. 2.45 Ga. However, the earliest traces of free oxygen during these periods, and the mechanisms of their sedimentary expression, remain poorly understood. For over a decade, the isotopic composition of molybdenum (δ98Mo) in sediments has been used as a global marine redox proxy.An elemental and isotopic study of the different phases constituting carbonate rocks was carried out using sequential digestions performed on carbonates of different ages and depositional environments. The results show that Mo is primarily... |
| Tipo: Text |
Palavras-chave: Redox; Précambrien; Carbonates; Molybdène; Isotopes; Attaque séquentielle; Sequential digestion; Precambrian; Molybdenum. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00663/77462/79129.pdf |
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| Malaize, B.; Joly, C.; Venec-peyre, M. -t.; Bassinot, F.; Caillon, N.; Charlier, K.. |
| High-resolution faunal and isotopic analyses of foraminifera were performed on core MD96-2073 (10 degrees 94'N, 52 degrees 62'E, 3142 m depth), located close to Socotra Island in the upwelling area of the Somali Basin ( NW Indian Ocean). This work focuses on Marine Isotopic Stage 6.5 in order to reconstruct paleo-upwelling changes and their links with the Arabian Sea summer monsoon and the migration of the Intertropical Convergence Zone (ITCZ). Correspondence and cluster analyses of planktonic foraminiferal abundances, partly controlled by temperature and water mass productivity, together with an upwelling intensification index, show the occurrence of a strong upwelling between 176 and 165 ka. This upwelling intensification responds to a northward... |
| Tipo: Text |
Palavras-chave: Paleoclimatology; Foraminifera; Isotopes; Indian monsoon; ITCZ; Sapropels; Upwelling. |
| Ano: 2006 |
URL: https://archimer.ifremer.fr/doc/00234/34487/33433.pdf |
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| Mougel, Berengere; Moreira, Manuel; Agranier, Arnaud. |
| We investigate in details helium isotope data reported in Mougel et al. (2014) for 14 basaltic samples collected on the East Pacific Rise by submersible (15 degrees 4N) where the ridge interacts with the Mathematician seamounts. Samples locations are separated by only few hundred meters across a 15km along-axis profile. The data reveal a strong geochemical variability that has never been observed at such high spatial resolution for helium isotope compositions. Moreover, they reveal an unusually high He-4/He-3 mantle component also characterized by unradiogenic lead, atypical in oceanic basalts. He-Pb systematics suggests a mixture between a nonradiogenic lead and radiogenic helium pyroxenitic component, recycled from the deep continental lithosphere and... |
| Tipo: Text |
Palavras-chave: Helium; Isotopes; Mantle geochemistry; MORB; Hot spot; EPR. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00639/75140/75500.pdf |
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| Decitre, S; Deloule, E; Reisberg, L; James, R; Agrinier, P; Mevel, C. |
| [1] Analyses of Li and Li isotopes in serpentinized peridotites have been performed using Thermo-Ionisation Mass Spectrometry (TIMS) and Secondary Ion Mass Spectrometry (SIMS) techniques on samples collected from the southwest Indian Ridge (SWIR). In the bulk samples, Li concentrations range from 0.6 to 8.2 ppm, while whole rock delta(6)Li values range from -2.9 to -14parts per thousand. In situ analyses display a greater range in both Li concentration (0.1-19.5 ppm) and Li isotopic composition ( -27 to +19parts per thousand), with the serpentinized portions having higher Li concentrations than the associated relict phases. These variations may reflect changes in Li partitioning and isotopic fractionation between serpentine and fluid with temperature and... |
| Tipo: Text |
Palavras-chave: Lithium; Isotopes; Geochemical cycle; Oceanic crust; Serpentinization. |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33403/31860.pdf |
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| Galbraith, Ed; Kienast, M; Pedersen, Tf; Calvert, Se. |
| An analysis of sedimentary nitrogen isotope records compiled from widely distributed marine environments emphasizes the global synchrony of denitrification changes and provides evidence for a strong temporal coupling of these variations to changes in nitrogen fixation as previously inferred. We explain the global coherence of these records by a simple physical control on the flux of dissolved oxygen to suboxic zones and the coupling to fixation via the supply of phosphorus to diazotrophs in suitable environments. According to our hypothesis, lower glacial-stage sea surface temperature increased oxygen solubility, while stronger winds in high-latitude regions enhanced the rate of thermocline ventilation. The resultant colder, rapidly flushed thermocline... |
| Tipo: Text |
Palavras-chave: Isotopes; Fixation; Denitrification. |
| Ano: 2004 |
URL: https://archimer.ifremer.fr/doc/00229/34026/32421.pdf |
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| Baronas, J. Jotautas; Torres, Mark A.; West, A. Joshua; Rouxel, Olivier; Georg, Bastian; Bouchez, Julien; Gaillardet, Jerome; Hammond, Douglas E.. |
| Solutes derived from the dissolution of silicate minerals play a key role in Earth’s climate via the carbon and other biogeochemical cycles. Silicon (Si) is a unique constituent of silicate minerals and a biologically important nutrient, so tracing its behavior in near-surface environments may provide important insights into weathering processes. However, Si released by weathering is variably incorporated into secondary mineral phases and biota, obscuring signals derived from primary weathering processes. Due to chemical similarities, Germanium (Ge) may help better understand the Si cycle and its relationship to chemical weathering. With this aim, we report new measurements of the concentration and isotopic composition of Ge for both the dissolved and... |
| Tipo: Text |
Palavras-chave: Germanium; Silicon; Isotopes; Rivers; Weathering; Fractionation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00460/57196/59370.pdf |
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| Weis, D; Frey, Fa; Schlich, R; Schaming, M; Montigny, R; Damasceno, D; Mattielli, N; Nicolaysen, Ke; Scoates, Js. |
| The gravity and bathymetric highs on the Kerguelen Plateau in the southern Indian Ocean between the Kerguelen Archipelago and Heard Island are seamounts formed of Miocene alkalic basalts similar to those found on the islands. Dredging during the Kerimis survey cruise recovered >1 ton of mostly basaltic rocks. One of the dredges (D6) yielded a large volume of in situ alkalic picritic pillow basalts, the first picritic lavas recovered that are related to the Kerguelen plume. K-Ar and Ar-40-Ar-39 ages are between 18 and 21 Ma for all but one sample, and these ages are only slightly younger than the main phase of volcanism on the archipelago. The dredged lavas form three distinct groups based on chemical and isotopic compositions. Incompatible element... |
| Tipo: Text |
Palavras-chave: Kerguelen; Trace elements; Isotopes; Mantle plume; Hot spot track; Picrites; Geochemistry; 1025 Geochemistry : Composition of the mantle; 1040 Geochemistry : Isotopic composition/chemistry; 1065 Geochemistry : Trace elements (3670). |
| Ano: 2002 |
URL: https://archimer.ifremer.fr/doc/00223/33407/31856.pdf |
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| Bourry, Christophe; Chazallon, Bertrand; Charlou, Jean-luc; Donval, Jean-pierre; Ruffine, Livio; Henry, Pierre; Geli, Louis; Cagatay, M. Namik; Inan, Sedat; Moreau, Myriam. |
| Gas hydrates and gas bubbles were collected during the MARNAUT cruise (May-June 2007) in the Sea of Marmara along the North Anatolian Fault system, Turkey. Gas hydrates were sampled in the western part of the Sea of Marmara (on the Western High), and three gas-bubble samples were recovered on the Western High, the Central High (center part of the Sea of Marmara) and in the Cinarcik Basin (eastern part of the Sea of Marmara). Methane is the major component of hydrates (66.1%), but heavier gases such as C-2, C-3, and i-C-4 are also present in relatively high concentration. The methane contained within gas hydrate is clearly thermogenic as evidenced by a low C-1/C-2 + C-3 ratio of 3.3, and carbon and hydrogen isotopic data (delta C-13(CH4) of -44.1 parts per... |
| Tipo: Text |
Palavras-chave: Isotopes; Thermogenic gas; Gas bubbles; Gas hydrate; Sea of Marmara. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6844.pdf |
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| Snow, Tasha. |
| The Arctic and North Atlantic underwent significant climactic changes since the Last Glacial Maximum (25,000 years before present (1950 AD); ka BP), but offsets in the timing of events between the two regions are poorly constrained due to age model uncertainties that arise from changing radiocarbon reservoir ages. Here, we use a relatively high-resolution, multi-proxy stable isotope and sedimentologic dataset from Eastern Fram Strait (ODP Leg 162 Site 986) marine sediments to constrain the timing of Svalbard/Barents Sea Ice Sheet decay and infer deglacial reservoir ages over the last 30 ka. We use magnetic susceptibility, inorganic and organic carbon, foraminiferal assemblage counts, planktonic foraminiferal isotopes, and iceberg-rafted debris proxies to... |
| Tipo: Text |
Palavras-chave: Paleoceanography; Meltwater; Isotopes; Foraminifera; Fram Strait; Reservoir age. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00499/61045/64452.pdf |
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| Schlitzer, Reiner; Anderson, Robert F.; Dodas, Elena Masferrer; Lohan, Maeve; Geibere, Walter; Tagliabue, Alessandro; Bowie, Andrew; Jeandel, Catherine; Maldonado, Maria T.; Landing, William M.; Cockwell, Donna; Abadie, Cyril; Abouchami, Wafa; Achterberg, Eric P.; Agather, Alison; Aguliar-islas, Ana; Van Aken, Hendrik M.; Andersen, Morten; Archer, Corey; Auro, Maureen; De Baar, Hein J.; Baars, Oliver; Baker, Alex R.; Bakker, Karel; Basak, Chandranath; Baskaran, Mark; Bates, Nicholas R.; Bauch, Dorothea; Van Beek, Pieter; Behrens, Melanie K.; Black, Erin; Bluhm, Katrin; Bopp, Laurent; Bouman, Heather; Bowman, Katlin; Bown, Johann; Boyd, Philip; Boye, Marie; Boyle, Edward A.; Branellec, Pierre; Bridgestock, Luke; Brissebrat, Guillaume; Browning, Thomas; Bruland, Kenneth W.; Brumsack, Hans-juergen; Brzezinski, Mark; Buck, Clifton S.; Buck, Kristen N.; Buesseler, Ken; Bull, Abby; Butler, Edward; Cai, Pinghe; Camara Mor, Patricia; Cardinal, Damien; Carlson, Craig; Carrasco, Gonzalo; Casacuberta, Nuria; Casciotti, Karen L.; Castrillejo, Maxi; Chamizo, Elena; Chance, Rosie; Charette, Matthew A.; Chaves, Joaquin E.; Cheng, Hai; Chever, Fanny; Christl, Marcus; Church, Thomas M.; Closset, Ivia; Colman, Albert; Conway, Tim M.; Cossa, Daniel; Croot, Peter; Cullen, Jay T.; Cutter, Gregory A.; Daniels, Chris; Dehairs, Frank; Deng, Feifei; Dieu, Huong Thi; Duggan, Brian; Dulaquais, Gabriel; Dumousseaud, Cynthia; Echegoyen-sanz, Yolanda; Edwards, R. Lawrence; Ellwood, Michael; Fahrbach, Eberhard; Fitzsimmons, Jessica N.; Flegal, A. Russell; Fleisher, Martin Q.; Van De Flierdt, Tina; Frank, Martin; Friedrich, Jana; Fripiat, Francois; Froellje, Henning; Galer, Stephen J. G.; Gamo, Toshitaka; Ganeshram, Raja S.; Garcia-orellana, Jordi; Garcia-solsona, Ester; Gault-ringold, Melanie; George, Ejin; Gerringa, Loes J. A.; Gilbert, Melissa; Godoy, Jose M.; Goldstein, Steven L.; Gonzalez, Santiago R.; Grissom, Karen; Hammerschmidt, Chad; Hartman, Alison; Hassler, Christel S.; Hathorne, Ed C.; Hatta, Mariko; Hawco, Nicholas; Hayes, Christopher T.; Heimburger, Lars-eric; Helgoe, Josh; Heller, Maija Iris; Henderson, Gideon M.; Henderson, Paul B.; Van Heuven, Steven; Ho, Peng; Horner, Tristan J.; Hsieh, Yu-te; Huang, Kuo-fang; Humphreys, Matthew P.; Isshiki, Kenji; Jacquot, Jeremy E.; Janssen, David J.; Jenkins, William J.; John, Seth; Jones, Elizabeth M.; Jones, Janice L.; Kadko, David C.; Kayser, Rick; Kenna, Timothy C.; Khondoker, Roulin; Kim, Taejin; Kipp, Lauren; Klar, Jessica K.; Klunder, Maarten; Kretschmer, Sven; Kumamoto, Yuichiro; Laan, Patrick; Labatut, Marie; Lacan, Francois; Lam, Phoebe J.; Lambelet, Myriam; Lamborg, Carl H.; Le Moigne, Frederic A. C.; Le Roy, Emilie; Lechtenfeld, Oliver J.; Lee, Jong-mi; Lherminier, Pascale; Little, Susan; Lopez-lora, Mercedes; Lu, Yanbin; Masque, Pere; Mawji, Edward; Mcclain, Charles R.; Measures, Christopher; Mehic, Sanjin; Barraqueta, Jan-lukas Menzel; Van Der Merwe, Pier; Middag, Rob; Mieruch, Sebastian; Milne, Angela; Minami, Tomoharu; Moffett, James W.; Moncoiffe, Gwenaelle; Moore, Willard S.; Morris, Paul J.; Morton, Peter L.; Nakaguchi, Yuzuru; Nakayama, Noriko; Niedermiller, John; Nishioka, Jun; Nishiuchi, Akira; Noble, Abigail; Obata, Hajime; Ober, Sven; Ohnemus, Daniel C.; Van Ooijen, Jan; O'Sullivan, Jeanette; Owens, Stephanie; Pahnke, Katharina; Paul, Maxence; Pavia, Frank; Pena, Leopoldo D.; Petersh, Brian; Planchon, Frederic; Planquette, Helene; Pradoux, Catherine; Puigcorbe, Viena; Quay, Paul; Queroue, Fabien; Radic, Amandine; Rauschenberg, S.; Rehkamper, Mark; Rember, Robert; Remenyi, Tomas; Resing, Joseph A.; Rickli, Joerg; Rigaud, Sylvain; Rijkenberg, Micha J. A.; Rintoul, Stephen; Robinson, Laura F.; Roca-marti, Montserrat; Rodellas, Valenti; Roeske, Tobias; Rolison, John M.; Rosenberg, Mark; Roshan, Saeed; Van Der Loaff, Michiel M. Rutgers; Ryabenko, Evgenia; Saito, Mak A.; Salt, Lesley A.; Sanial, Virginie; Sarthou, Geraldine; Schallenberg, Christina; Schauer, Ursula; Scher, Howie; Schlosser, Christian; Schnetger, Bernhard; Scott, Peter; Sedwick, Peter N.; Semiletov, Igor; Shelley, Rachel; Sherrell, Robert M.; Shiller, Alan M.; Sigman, Daniel M.; Singh, Sunil Kumar; Slagter, Hans A.; Slater, Emma; Smethie, William M.; Snaith, Helen; Sohrin, Yoshiki; Sohst, Bettina; Sonke, Jeroen E.; Speich, Sabrina; Steinfeldt, Reiner; Stewart, Gillian; Stichel, Torben; Stirling, Claudine H.; Stutsman, Johnny; Swarr, Gretchen J.; Swift, James H.; Thomas, Alexander; Thorne, Kay; Till, Claire P.; Till, Ralph; Townsend, Ashley T.; Townsend, Emily; Tuerena, Robyn; Twining, Benjamin S.; Vance, Derek; Velazquez, Sue; Venchiarutti, Celia; Villa-alfageme, Maria; Vivancos, Sebastian M.; Voelker, Antje H. L.; Wake, Bronwyn; Warner, Mark J.; Watson, Ros; Van Weerlee, Evaline; Weigand, M. Alexandra; Weinstein, Yishai; Weiss, Dominik; Wisotzki, Andreas; Woodward, E. Malcolm S.; Wu, Jingfeng; Wu, Yingzhe; Wuttig, Kathrin; Wyatt, Neil; Xiang, Yang; Xie, Ruifang C.; Xue, Zichen; Yoshikawa, Hisayuki; Zhang, Jing; Zhang, Pu; Zhao, Ye; Zheng, Linjie; Zheng, Xin-yuan; Zieringer, Moritz; Zimmer, Louise A.; Ziveri, Patrizia; Zunino, Patricia; Zurbrick, Cheryl. |
| The new IDP2017 is a significant improvement over the earlier IDP2014 and roughly doubles the number of included cruises, stations, samples and parameters. The IDP2017 is a truly international product containing data from 326 researchers from 25 countries. The IDP2017 provides data for the Pacific Ocean, and the Mediterranean and Black seas, in addition to Atlantic, Arctic and Indian Oceans that were already represented in the previous data product. For the first time, the IDP2017 contains significant amounts of biogeochemistry data as well as TEI data for aerosols and rain. As before, users can obtain complete IDP2017 data sets as bulk downloads. Alternatively, there is now a customisable online data extraction service that allows data selections by... |
| Tipo: Text |
Palavras-chave: GEOTRACES; Trace elements; Isotopes; Electronic atlas; IDP2017. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00442/55362/56877.pdf |
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| Beaumais, Aurelien; Chazot, Gilles; Dosso, Laure; Bertrand, Herve. |
| Here we present a new geochemical study of Lopevi volcano, one the most active volcanoes in the Vanuatu island arc. We focus on the temporally well-defined sequence of lava flows emitted since 1960, and for the first time, on pre-1960 volcanic products, including high-MgO basalts and felsic andesites, the most evolved lavas sampled so far on this island. This work reports the first Pb and Hf isotopic study of lavas from Lopevi island. These lavas display correlations between differentiation indexes such as SiO2 content and isotopic ratios. The felsic andesites extend the known correlations with both the least (Sr-Pb) and the most (Nd-Hf) radiogenic isotopic compositions on the island. Our results confirm that the rising magma interacted with the sub-arc... |
| Tipo: Text |
Palavras-chave: Lopevi; Vanuatu; Geochemistry; Isotopes; Subduction; Mantle source. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00167/27801/26223.pdf |
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| Mawji, Edward; Schlitzer, Reiner; Dodas, Elena Masferrer; Abadie, Cyril; Abouchami, Wafa; Anderson, Robert F.; Baars, Oliver; Bakker, Karel; Baskaran, Mark; Bates, Nicholas R.; Bluhm, Katrin; Bowie, Andrew; Bown, Johann; Boye, Marie; Boyle, Edward A.; Branellec, Pierre; Bruland, Kenneth W.; Brzezinski, Mark A.; Bucciarelli, Eva; Buesseler, Ken; Butler, Edward; Cai, Pinghe; Cardinal, Damien; Casciotti, Karen; Chaves, Joaquin; Cheng, Hai; Chever, Fanny; Church, Thomas M.; Colman, Albert S.; Conway, Tim M.; Croot, Peter L.; Cutter, Gregory A.; De Baar, Hein J. W.; De Souza, Gregory F.; Dehairs, Frank; Deng, Feifei; Huong Thi Dieu,; Dulaquais, Gabriel; Echegoyen-sanz, Yolanda; Edwards, R. Lawrence; Fahrbach, Eberhard; Fitzsimmons, Jessica; Fleisher, Martin; Frank, Martin; Friedrich, Jana; Fripiat, Francois; Galer, Stephen J. G.; Gamo, Toshitaka; Solsona, Ester Garcia; Gerringa, Loes J. A.; Godoy, Jose Marcus; Gonzalez, Santiago; Grossteffan, Emilie; Hatta, Mariko; Hayes, Christopher T.; Heller, Maija Iris; Henderson, Gideon; Huang, Kuo-fang; Jeandel, Catherine; Jenkins, William J.; John, Seth; Kenna, Timothy C.; Klunder, Maarten; Kretschmer, Sven; Kumamoto, Yuichiro; Laan, Patrick; Labatut, Marie; Lacan, Francois; Lam, Phoebe J.; Lannuzel, Delphine; Le Moigne, Frederique; Lechtenfeld, Oliver J.; Lohan, Maeve C.; Lu, Yanbin; Masque, Pere; Mcclain, Charles R.; Measures, Christopher; Middag, Rob; Moffett, James; Navidad, Alicia; Nishioka, Jun; Noble, Abigail; Obata, Hajime; Ohnemus, Daniel C.; Owens, Stephanie; Planchon, Frederic; Pradoux, Catherine; Puigcorbe, Viena; Quay, Paul; Radic, Amandine; Rehkaemper, Mark; Remenyi, Tomas; Rijkenberg, Micha J. A.; Rintoul, Stephen; Robinson, Laura F.; Roeske, Tobias; Rosenberg, Mark; Van Der Loeff, Michiel Rutgers; Ryabenko, Evgenia; Saito, Mak A.; Roshan, Saeed; Salt, Lesley; Sarthou, Geraldine; Schauer, Ursula; Scott, Peter; Sedwick, Peter N.; Sha, Lijuan; Shiller, Alan M.; Sigman, Daniel M.; Smethie, William; Smith, Geoffrey J.; Sohrin, Yoshiki; Speich, Sabrina; Stichel, Torben; Stutsman, Johnny; Swift, James H.; Tagliabue, Alessandro; Thomas, Alexander; Tsunogai, Urumu; Twining, Benjamin S.; Van Aken, Hendrik M.; Van Heuven, Steven; Van Ooijen, Jan; Van Weerlee, Evaline; Venchiarutti, Celia; Voelker, Antje H. L.; Wake, Bronwyn; Warner, Mark J.; Woodward, E. Malcolm S.; Wu, Jingfeng; Wyatt, Neil; Yoshikawa, Hisayuki; Zheng, Xin-yuan; Xue, Zichen; Zieringer, Moritz; Zimmer, Louise A.. |
| The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of the international GEOTRACES programme, and contains data measured and quality controlled before the end of 2013. It consists of two parts: (1) a compilation of digital data for more than 200 trace elements and isotopes (TEls) as well as classical hydrographic parameters, and (2) the eGEOTRACES Electronic Atlas providing a strongly inter-linked on-line atlas including more than 300 section plots and 90 animated 3D scenes. The IDP2014 covers the Atlantic, Arctic, and Indian oceans, exhibiting highest data density in the Atlantic. The TEI data in the IDP2014 are quality controlled by careful assessment of intercalibration results and multi-laboratory data... |
| Tipo: Text |
Palavras-chave: GEOTRACES; Trace elements; Isotopes; Electronic atlas. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00308/41910/41190.pdf |
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| Schmittner, Andreas; Bostock, Helen C.; Cartapanis, Olivier; Curry, William B.; Filipsson, Helena L.; Galbraith, Eric D.; Gottschalk, Julia; Carlos Herguera, Juan; Hoogakker, Babette; Jaccard, Samuel L.; Lisiecki, Lorraine E.; Lund, David C.; Martinez-mendez, Gema; Lynch-stieglitz, Jean; Mackensen, Andreas; Michel, Elisabeth; Mix, Alan C.; Oppo, Delia W.; Peterson, Carlye D.; Repschlaeger, Janne; Sikes, Elisabeth L.; Spero, Howard J.; Waelbroeck, Claire. |
| The carbon isotope composition (C-13) of seawater provides valuable insight on ocean circulation, air-sea exchange, the biological pump, and the global carbon cycle and is reflected by the C-13 of foraminifera tests. Here more than 1700 C-13 observations of the benthic foraminifera genus Cibicides from late Holocene sediments (C-13(Cibnat)) are compiled and compared with newly updated estimates of the natural (preindustrial) water column C-13 of dissolved inorganic carbon (C-13(DICnat)) as part of the international Ocean Circulation and Carbon Cycling (OC3) project. Using selection criteria based on the spatial distance between samples, we find high correlation between C-13(Cibnat) and C-13(DICnat), confirming earlier work. Regression analyses indicate... |
| Tipo: Text |
Palavras-chave: Carbon; Isotopes; Benthic; Foraminifera; Calibration. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00661/77326/78788.pdf |
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| Beaumais, Aurelien; Bertrand, Herve; Chazot, Gilles; Dosso, Laure; Robin, Claude. |
| Gaua Island (also called Santa Maria), from the central part of the Vanuatu arc, consists of a large volcano marked by a caldera that hosts the active Mount Garet summit cone. In this paper, a geochemical study including Sr, Nd, Pb and Hf isotopic compositions of 25 lavas emitted since 1.8 Ma is presented, with a focus on the volcanic products that preceded (old volcanics, main cone and pyroclastic series) and followed (Mount Garet) the caldera forming event. All lavas show an island arc signature with enrichment in LILE and depletion in HFSE. Post-caldera lavas define a medium-K calc-alkaline trend, whereas lavas from the former main cone have high-K calc-alkaline compositions. Compared to the pre-caldera volcanic suite, the Mount Garet lavas have... |
| Tipo: Text |
Palavras-chave: Gaua; Vanuatu; Geochemistry; Isotopes; Subduction; Mantle source. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00319/43052/42557.pdf |
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| Meyzen, Cm; Ludden, Jn; Humler, E; Luais, B; Toplis, Mj; Mevel, C; Storey, M. |
| We report new Sr, Nd, and Pb isotope data for Mid-Ocean Ridge Basalts (MORB) dredged between 35 and 69 degrees E along a similar to 4100 km section of the Southwest Indian Ridge (SWIR), which is one of the slowest spreading ridges of the global mid-ocean ridge system ( full rate of 16 mm yr(-1)). The SWIR appears isotopically more heterogeneous than other mid-ocean ridges over similar length scales and comparable sampling density. Isotopic variations are generally independent of ridge segmentation, and the degree of heterogeneity decreases from west to east. This decrease in heterogeneity correlates with the observed increase in axial depth and decrease in crustal thickness, commonly attributed to decreasing mantle potential temperature. Data for the... |
| Tipo: Text |
Palavras-chave: Southwest Indian Ridge; MORB; Isotopes; Indian Ocean; Lower crust; Mantle. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34286/32655.pdf |
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| Registros recuperados: 29 | |
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