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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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| Peron, Sandrine; Moreira, Manuel; Agranier, Arnaud. |
| We review the different scenarios for the origin of light noble gases (He, Ne, and Ar) on Earth. Several sources could have contributed to the Earth's noble gas budget: implanted solar wind, solar nebula gas, chondrites, and comets. Although there is evidence for solar-like neon in the Earth's mantle, questions remain as to its origin. A new compilation of noble gas data in lunar soils, interplanetary dust particles, micrometeorites, and solar wind allows examination of the implanted solar wind composition, which is key to understanding the solar-like mantle neon isotope composition. We show that lunar soils that reflect this solar-wind-implanted signature have a Ne-20/Ne-22 ratio very close to that of ocean island basalts. New data and calculations... |
| Tipo: Text |
Palavras-chave: Volatile origin; Helium; Neon; Argon; Solar wind implantation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00638/74992/75837.pdf |
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| Paquet, Marine; Hamelin, Cédric; Moreira, Manuel; Cannat, Mathilde. |
| The eastern Southwest Indian Ridge, between 61° and 67°E, has a very low melt supply and comprises several corridors of nearly amagmatic spreading that expose mantle-derived serpentinized peridotite. More volcanically active ridge portions separate these corridors. He, Ne, Pb, Nd, Hf and Sr isotopes were analyzed in basalt glasses dredged on two types of seafloor: volcanic and ultramafic. Basalts dredged in ultramafic seafloor on-axis tend to be slightly more depleted for heavy radiogenic isotopes and show slightly higher 3He/4He isotope ratios than basalts dredged in volcanic seafloor, with no systematic difference in neon isotope ratios. We propose that both types of basalts are derived from the same mantle source, but that the basalts dredged on... |
| Tipo: Text |
Palavras-chave: Mid-Ocean Ridge Basalts; Mantle heterogeneity; Noble gases; Isotope geochemistry; Melt/mantle interactions. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00633/74525/74360.jpg |
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| Hamelin, Cedric; Dosso, Laure; Hanan, Barry B.; Moreira, Manuel; Kositsky, Andrew P.; Thomas, Marion Y.. |
| Samples collected during the PACANTARCTIC 2 cruise fill a sampling gap from 53 degrees to 41 degrees S along the Pacific Antarctic Ridge (PAR). Analysis of Sr, Nd, Pb, Hf, and He isotope compositions of these new samples is shown together with published data from 66 degrees S to 53 degrees S and from the EPR. The recent advance in analytical mass spectrometry techniques generates a spectacular increase in the number of multidimensional isotopic data for oceanic basalts. Working with such multidimensional datasets generates a new approach for the data interpretation, preferably based on statistical analysis techniques. Principal Component Analysis (PCA) is a powerful mathematical tool to study this type of datasets. The purpose of PCA is to reduce the... |
| Tipo: Text |
Palavras-chave: Oceanic basalts; Pacific-Antarctic Ridge; Mantle heterogeneity; Principal Component Analysis; Sr Nd Pb Hf isotopes. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00031/14197/11508.pdf |
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