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| Registros recuperados: 19 | |
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| Nabiei, Farhang; Badro, James; Dennenwaldt, Teresa; Oveisi, Emad; Cantoni, Marco; Hebert, Cecile; El Goresy, Ahmed; Barrat, Jean-alix; Gillet, Philippe. |
| Planetary formation models show that terrestrial planets are formed by the accretion of tens of Moon-to Mars-sized planetary embryos through energetic giant impacts. However, relics of these large proto-planets are yet to be found. Ureilites are one of the main families of achondritic meteorites and their parent body is believed to have been catastrophically disrupted by an impact during the first 10 million years of the solar system. Here we studied a section of the Almahata Sitta ureilite using transmission electron microscopy, where large diamonds were formed at high pressure inside the parent body. We discovered chromite, phosphate, and (Fe, Ni)-sulfide inclusions embedded in diamond. The composition and morphology of the inclusions can only be... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00638/74991/75825.pdf |
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| Le Goff, Samuel; Barrat, Jean-alix; Chauvaud, Laurent; Paulet, Yves-marie; Gueguen, Bleuenn; Ben Salem, Douraied. |
| Gadolinium-based contrast agents (GBCAs), routinely used in magnetic resonance imaging (MRI), end up directly in coastal seawaters where gadolinium concentrations are now increasing. Because many aquatic species could be sensitive to this new pollution, we have evaluated the possibility of using shellfish to assess its importance. Gadolinium excesses recorded by scallop shells collected in Bay of Brest (Brittany, France) for more than 30 years do not reflect the overall consumption in GBCAs, but are largely controlled by one of them, the gadopentetate dimeglumine. Although its use has been greatly reduced in Europe over the last ten years, gadolinium excesses are still measured in shells. Thus, some gadolinium derived from other GBCAs is bioavailable and... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00615/72758/72029.pdf |
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| Freslon, Nicolas; Bayon, Germain; Birot, Dominique; Bollinger, Claire; Barrat, Jean-alix. |
| This paper reports on a novel procedure for determining trace element abundances (REE and Y, Cr, Mn, Co) in seawater by inductively coupled plasma sector field mass spectrometry (ICP-SFMS). The procedure uses a combination of pre-concentration using co-precipitation onto magnesium hydroxides and addition of thulium spike. The validity of the method was assessed onto 25 ml volumes of certified reference materials (NASS- and CASS-4) and in house seawater standard. Procedural blanks were determined by applying the same procedure to aliquots of seawater previously depleted in trace elements by successive Mg(OH)(2) co-precipitations, yielding estimated contributions to the studied samples better than 1.1% for all elements, with the exception of Cr (<3.3%)... |
| Tipo: Text |
Palavras-chave: Trace elements; Rare earth elements (REE); Seawater; Mg(OH)(2) co-precipitation; ICP-MS; Thulium. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00041/15220/15855.pdf |
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| Barrat, Jean-alix; Dauphas, N.; Gillet, P.; Bollinger, C.; Etoubleau, Joel; Bischoff, A.; Yamaguchi, A.. |
| Thulium is a heavy rare earth element (REE) whose geochemical behavior is intermediate between Er and Yb, and that is not expected to be decoupled from these elements during accretion of planetary bodies and geological processes. However, irregularities in REE volatilities at higher temperature could have decoupled the REEs relative to one another during the early stages of condensation of the solar nebula. Indeed, positive Tm anomalies are found in some refractory inclusions from carbonaceous chondrites, and it is possible that large scale nebular reservoirs displaying positive or negative Tm anomalies were formed during the early history of the solar system. We analyzed a series of meteorites and terrestrial rocks in order to evaluate the existence of Tm... |
| Tipo: Text |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00302/41338/40524.pdf |
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| Greenwood, Richard C.; Barrat, Jean-alix; Scott, Edward R. D.; Haack, Henning; Buchanan, Paul C.; Franchi, Ian A.; Yamaguchi, Akira; Johnson, Diane; Bevan, Alex W. R.; Burbine, Thomas H.. |
| Evidence from iron meteorites indicates that a large number of differentiated planetesimals formed early in Solar System history. These bodies should have had well-developed olivine-rich mantles and consequentially such materials ought to be abundant both as asteroids and meteorites, which they are not. To investigate this "Great Dunite Shortage" we have undertaken a geochemical and oxygen isotope study of main-group pallasites and dunitic rocks from mesosiderites. Oxygen isotope analysis of 24 main-group pallasites (103 replicates) yielded a mean Delta O-17 value of -0.187 +/- 0.016 parts per thousand (2 sigma), which is fully resolved from the HED Delta O-17 value of -0.246 +/- 0.014 (2 sigma) obtained in our earlier study and demonstrates that both... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00639/75112/75443.pdf |
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| Wang, X.; Barrat, Jean-alix; Bayon, Germain; Chauvaud, Laurent; Feng, D.. |
| Methane is an important greenhouse gas whose emissions into the oceans and atmosphere are regulated by relatively unconstrained anaerobic and aerobic microbial processes. The aerobic pathway for methane oxidation is thought to be largely dependent upon the use of rare earth elements (REE), but to date the effects of this process on their abundances in bacteria or in organisms living in symbiosis with methanotrophs remain to be evaluated. Here we show that deep sea chemosynthetic mussels prospering at methane seeps display distinctive lanthanum enrichments linked to the enzymatic activities of their symbionts. These results demonstrate that methanotrophy is able to fractionate efficiently REE distributions in organisms and possibly in the environment.... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00643/75532/76427.pdf |
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| Barrat, Jean-alix; Ferrière, L.. |
| Main-group pallasites (MGPs) are meteorites mainly composed of Fe-Ni metal and olivines, the latter being considered as one of the largest sampling of extraterrestrial mantle material available for study on Earth. We analysed the rare earth element (REE) concentrations of olivines from six MGPs to understand better the processes of formation of their parent mantle. All the investigated samples display very low REE abundances, and enrichments in both light REEs and heavy REEs. We interpret the light REE enrichments as a fingerprint of terrestrial contamination. The least contaminated olivines have higher heavy REE enrichments than those inferred for olivines directly crystallised in a magma ocean. Such enrichments in heavy REEs are possible if the mantle of... |
| Tipo: Text |
Palavras-chave: Pallasite; Early solar system; Trace elements; Rare earth elements; Differentiation. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00686/79770/82569.pdf |
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| Greenwood, Richard C.; Barrat, Jean-alix; Miller, Martin F.; Anand, Mahesh; Dauphas, Nicolas; Franchi, Ian A.; Sillard, Patrick; Starkey, Natalie A.. |
| The Earth-Moon system likely formed as a result of a collision between two large planetary objects. Debate about their relative masses, the impact energy involved, and the extent of isotopic homogenization continues. We present the results of a high-precision oxygen isotope study of an extensive suite of lunar and terrestrial samples. We demonstrate that lunar rocks and terrestrial basalts show a 3 to 4 ppm (parts per million), statistically resolvable, difference in Delta O-17. Taking aubrite meteorites as a candidate impactor material, we show that the giant impact scenario involved nearly complete mixing between the target and impactor. Alternatively, the degree of similarity between the Delta O-17 values of the impactor and the proto-Earth must have... |
| Tipo: Text |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00638/74995/75750.pdf |
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| Yamaguchi, A.; Barrat, Jean-alix; Shirai, N.; Ebihara, M.. |
| We performed a petrological and geochemical study of an olivine diogenite, Northwest Africa (NWA) 5480. NWA 5480 is a crystalline stone, but shows a heterogeneous texture. Olivine aggregates and grains of olivine and chromite display resorption textures set in a crystalline pyroxene matrix. Large olivine aggregates are penetrated by pyroxene matrix. Flow textures are observed near olivine aggregates. Olivine, chromite, and pyroxene show minor chemical zoning, implying relatively rapid cooling. NWA 5480 contains a significant amount of platinum group elements with chondritic relative proportions. All this evidence supports that NWA 5480 is an impact-melt breccia from a target composed of olivine and pyroxene-rich lithologies. Such impact melt would have... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00639/75131/75519.pdf |
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| Bayon, Germain; Toucanne, Samuel; Skonieczny, Charlotte; Andre, L.; Bermell, Sylvain; Cheron, Sandrine; Dennielou, Bernard; Etoubleau, Joel; Freslon, Nicolas; Gauchery, T.; Germain, Yoan; Jorry, Stephan; Menot, G.; Monin, L.; Ponzevera, Emmanuel; Rouget, M. -l.; Tachikawa, K.; Barrat, Jean-alix. |
| Over the past decades, rare earth elements (REE) and their radioactive isotopes have received tremendous attention in sedimentary geochemistry, as tracers for the geological history of the continental crust and provenance studies. In this study, we report on elemental concentrations and neodymium (Nd) isotopic compositions for a large number of sediments collected near the mouth of rivers worldwide, including some of the world’s major rivers. Sediments were leached for removal of non-detrital components, and both clay and silt fractions were retained for separate geochemical analyses. Our aim was to re-examine, at the scale of a large systematic survey, whether or not REE and Nd isotopes could be fractionated during Earth surface processes. Our results... |
| Tipo: Text |
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| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00276/38733/37249.pdf |
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| Hamelin, Cedric; Dosso, Laure; Hanan, Barry; Barrat, Jean-alix; Ondreas, Helene. |
| Major, trace element and Sr-Nd-Hf isotope data in basalts collected along the Pacific-Antarctic Ridge ( PAR) axis between 53 and 41 S, far from any hotspot influence, reveal tight coherent geochemical variations within the depleted MORB mantle. All samples are located below the Pacific reference line defining two sub-oceanic mantle domains on each side of the Easter microplate. The data extend the PAR 66-53 S field towards more radiogenic Sr (0.70264), less radiogenic Nd (epsilon = 7.7) and Hf (epsilon = 11.4) values. The along ridge geochemical variability is closely related to the morphological segmentation of the ridge. Anomalous geochemical features are attributed to the atypical morphology of two segments due to the presence of off-axis magmatism. The... |
| Tipo: Text |
Palavras-chave: Pacific-Antarctic; Depleted mantle; Sr-Nd-Hf isotopes. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00004/11526/8123.pdf |
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| Bischoff, Addi; Alexander, Conel M. O'D; Barrat, Jean-alix; Burkhardt, Christoph; Busemann, Henner; Degering, Detlev; Di Rocco, Tommaso; Fischer, Meike; Fockenberg, Thomas; Foustoukos, Dionysis, I; Gattacceca, Jerome; Godinho, Jose R. A.; Harries, Dennis; Heinlein, Dieter; Hellmann, Jan L.; Hertkorn, Norbert; Holm, Anja; Jull, A. J. Timothy; Kerraouch, Imene; King, Ashley J.; Kleine, Thorsten; Koll, Dominik; Lachner, Johannes; Ludwig, Thomas; Merchel, Silke; Mertens, Cornelia A. K.; Morino, Precillia; Neumann, Wladimir; Pack, Andreas; Patzek, Markus; Pavetich, Stefan; Reitze, Maximilian P.; Rufenacht, Miriam; Rugel, Georg; Schmidt, Charlotte; Schmitt-kopplin, Philippe; Schonbachler, Maria; Trieloff, Mario; Wallner, Anton; Wimmer, Karl; Woelfer, Elias. |
| On September 12, 2019 at 12:49:48 (UT) a bolide was observed by hundreds of eye-witnesses from the Netherlands, Germany, Belgium, Denmark and the UK. One day later a small meteorite stone was found by accident in Flensburg. The presence of short-lived cosmogenic radionuclides with half-lives as short as 16 days proves the recent exposure of the found object to cosmic rays in space linking it clearly to the bolide event. An exceptionally short exposure time of similar to 5000 years was determined. The 24.5 g stone has a fresh black fusion crust, a low density of <2 g/cm(3), and a magnetic susceptibility of log chi = 4.35 (chi in 10(-9) m(3)/kg). The rock consists of relict chondrules and clusters of sulfide and magnetite grains set in a fine-grained... |
| Tipo: Text |
Palavras-chave: C1 chondrite; Carbonaceous chondrite; Aqueous alteration; Carbonates; Early solar system; Oldest carbonates in solar system; Unique chondrite; Ungrouped C chondrite. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00686/79845/82672.pdf |
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| Bischoff, Addi; Barrat, Jean-alix; Berndt, Jasper; Borovicka, Jiri; Burkhardt, Christoph; Busemann, Henner; Hakenmueller, Janina; Heinlein, Dieter; Hertzog, Jasmine; Kaiser, Jozef; Maden, Colin; Meier, Matthias M. M.; Morino, Precillia; Pack, Andreas; Patzek, Markus; Reitze, Maximilian P.; Rufenacht, Miriam; Schmitt-kopplin, Philippe; Schonbachler, Maria; Spurny, Pavel; Weber, Iris; Wimmer, Karl; Zikmund, Tomas. |
| On July 10, 2018 at 21:29 UT extended areas of South-Western Germany were illuminated by a very bright bolide. This fireball was recorded by instruments of the European Fireball Network (EN). The records enabled complex and precise description of this event including the prediction of the impact area. So far six meteorites totaling about 1.23 kg have been found in the predicted location for a given mass during dedicated searches. The first piece of about 12 g was recovered on July 24 close to the village of Renchen (Baden-Wurttemberg) followed by the largest fragment of 955 g on July 31 about five km north-west of Renchen. Renchen is a moderately-shocked (S4) breccia consisting of abundant highly recrystallized rock fragments as well as impact melt rock... |
| Tipo: Text |
Palavras-chave: Ordinary chondrite; Chondrite breccia; L chondrite; Meteorite fall. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74895/75971.pdf |
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| Zhu, Ke; Moynier, Frederic; Wielandt, Daniel; Larsen, Kirsten K.; Barrat, Jean-alix; Bizzarro, Martin. |
| Angrite meteorites are some of the oldest materials in the solar system. They provide important information on the earliest evolution of the solar system and accretion timescales of protoplanets. Here, we show that the Cr-54/Cr-52 ratio is homogeneously distributed among angrite meteorites within 13 parts per million, indicating that precursor materials must have experienced a global-scale melting such as a magma ocean. The Cr-53/Cr-52 and Mn/Cr ratios are correlated, which is evidence for an initial Mn-53/Mn-55 ratio of (3.16 +/- 0.11) x 10(-6). When anchored to the U-corrected Pb-Pb age for the D'Orbigny angrite, this initial 53Mn/55Mn corresponds to an absolute age of 4563.2 +/- 0.3 Ma, i.e., 4.1 +/- 0.3 Ma after Ca-Al-rich inclusion-formation. This age... |
| Tipo: Text |
Palavras-chave: Astrochemistry meteorites; Meteors; Meteoroids nuclear reactions; Nucleosynthesis; Abundances. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00637/74934/76011.pdf |
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| Charles, Claire; Barrat, Jean-alix; Pelleter, Ewan. |
| In order to propose an optimal analytical procedure specific to ferromanganese (Fe-Mn) oxides, we investigated different modes of data acquisition using inductively coupled plasma mass spectrometry (ICP-MS). The results of trace element and Rare Earth Element (REE) determination in eight Fe-Mn nodules and crusts (FeMn-1, GSMC-1, GSMC-2, GSMC-3, GSPN-2, GSPN-3, NOD-A-1 and NOD-P-1) are presented here. The analytical procedure involves chemical dissolution of the Fe-Mn oxides and addition of a thulium (Tm) spike. The correction of measured values from potential isobaric interferences was investigated using both corrections based on mono-elemental solutions, and data acquisition in the high-resolution mode. The obtained results show that the high-resolution... |
| Tipo: Text |
Palavras-chave: ICP-MS; Fe-Mn oxides; Trace elements; Rare earth elements; High-resolution; Tm spike. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00692/80377/83498.pdf |
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| Wang, Xudong; Bayon, Germain; Kim, Jung-hyun; Lee, Dong-hun; Kim, Dahae; Guéguen, Bleuenn; Rouget, Marie-laure; Barrat, Jean-alix; Toffin, Laurent; Feng, Dong. |
| Seeping of methane-rich fluids at submarine cold seeps drives intense microbial activity and precipitation of authigenic carbonates. Some trace elements play an important role in the biogeochemical processes operating at cold seeps, especially as specific enzymatic co-factors related to methanogenesis and the anaerobic oxidation of methane (AOM). However, it is unclear whether microbial trace metal utilization can be traced by the geochemical composition of seep carbonates. In this study, we analyzed a series of authigenic carbonate samples recovered from various seep settings worldwide and report for the first time trace element concentrations for total lipid fractions, combined with biomarker analyses and determination of elemental abundances in... |
| Tipo: Text |
Palavras-chave: Seep carbonate; Lipid compounds; Trace elements; Tungsten; Nickel; Cobalt; Molybdenum. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00511/62311/66562.pdf |
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| Brugier, Yann-aurélien; Barrat, Jean-alix; Gueguen, Bleuenn; Agranier, Arnaud; Yamaguchi, Akira; Bischoff, Addi. |
| The Ureilite Parent Body (UPB) was a C-rich planetary embryo disrupted by impact. Ureilites are fragments of the UPB mantle and among the most numerous achondrites. Zinc isotopic data are presented for 26 unbrecciated ureilites and a trachyandesite (ALM-A) from the same parent body. The δ66Zn values of ureilites range from 0.40 to 2.71 ‰ including literature results. Zinc isotopic compositions do not correlate with the compositions of olivine cores, with C and O isotopic compositions, with Zn abundances, nor with shock grades. The wide range of δ66Zn displayed by the ureilites is chiefly explained by evaporation processes that took place during the catastrophic breakup of the UPB. During breakup, the high temperatures of the UPB mantle allowed Zn to... |
| Tipo: Text |
Palavras-chave: Ureilite; Zinc isotopic composition; Isotope fractionation; Shock. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00472/58335/60889.pdf |
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| Registros recuperados: 19 | |
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