Éditeur(s) : HAL CCSD
Résumé : This study provides additional constraints on the relations between deformation, hydration and percolation of fluids and melts in the subcontinental lithospheric mantle beneath a craton and a rift, as well as their implication on its geodynamical behaviour. I have analysed the microstructures, the CPOs, and the hydrogen content of mantle xenoliths from the Kaapvaal craton, and two sets of xenoliths from different localities along the East African Rift (North Tanzanian Divergence and SE Ethiopia).The coarse-granular microstructures and the well-defined CPOs in Kaapvaal peridotites suggest a deformation followed by a long quiescence time. Orthorhombic olivine CPOs predominates, but axial-[100] and axial-[010] are also measured. Cratonic peridotites record multiple metasomatic episodes, leading to a significant compositional heterogeneity, which cannot be imaged by seismic studies. Olivine hydrogen contents are variable, but tend to increase until 150 km depth, reaching up to 50 ppm wt. H2O. The deeper samples are almost dry. Piston-cylinder experiments on hydrogen diffusion between a volatile-rich kimberlitic melt and forsterite suggest that the presence of CO2 in the system could significantly decrease water fugacity and thus forsterite hydration. These experimental results indicate that the hydrogen contents measured in olivine were acquired during a metasomatic event rather than during xenolith extraction by kimberlites. However, this metasomatism was not followed by remobilization of the cratonic root.In the North Tanzanian Divergence, localities within the rift axis and the volcanic transverse belt (Lashaine and Olmani) show significant differences in microstructures and olivine CPO patterns. In Lashaine, coarse-granular microstructures and orthorhombic to axial-[100] CPO patterns in olivine can be explained by transpressional deformation during the formation of the Mozambique belt, or by the occurrence of a remnant of a cratonic domain embedded within the Mozambique belt. Within the rift axis, porphyroclastic to mylonitic microstructures suggest a recent rift-related deformation accompanied by syn-kinematic melt-rock reactions, and followed by variable annealing. The strong heterogeneity in microstructures and olivine CPO suggests that this deformation was acquired during multiple tectonic events probably linked to episodic magma percolation, separated by quiescence episodes. The axial-[100] patterns in olivine and the oblique fast directions reported by SKS studies are coherent with transtensional deformation within the lithospheric mantle beneath the rift.The peridotites from SE Ethiopia are less recrystallized than the rift-axis Tanzanian peridotites, displaying coarse-porphyroclastic microstructures. Microstructures and orthorhombic CPOs in olivine suggest syn- to post-metasomatic deformation. S-waves polarization anisotropies calculated for these samples cannot explain alone the delay times reported by SKS studies in this part of the East-African Rift.
Les travaux réalisés durant cette thèse apportent de nouvelles contraintes sur les relations entre déformation, hydratation et percolation de fluides et/ou de magmas dans le manteau subcontinental sous un craton et sous un rift, et leurs implications sur son comportement rhéologique. Il repose sur l'analyse des microstructures, des OPRs et des teneurs en hydrogène de xénolites mantelliques du craton du Kaapvaal, et sur deux séries de xénolites provenant de différentes localités le long du rift Est-Africain (Divergence Nord Tanzanienne et SE de l'Ethiopie). Les microstructures granulaires à gros grains et les OPRs bien définies des péridotites du craton du Kaapvaal sont cohérentes avec un épisode de déformation suivi d'une longue période de quiescence. Les OPRs de l'olivine sont majoritairement à symétrie orthorhombique, mais des symétries axiale-[100] et axiale-[010] sont aussi mesurées. Les péridotites cratoniques enregistrent de multiples épisodes métasomatiques, ayant entraîné une hétérogénéité de compositions à petite échelle ne pouvant être détectée par les études sismiques. Les teneurs en hydrogène mesurées dans l'olivine sont variables, mais ont tendance à augmenter jusqu'à 150 km de profondeur, atteignant alors jusqu'à 50 ppm wt. H2O. En dessous de cette profondeur, les échantillons montrent des teneurs en hydrogène très faibles. Les expériences réalisées en piston-cylindre sur la diffusion de l'hydrogène issue d'un liquide kimberlitique vers de la forstérite suggèrent que la fugacité en eau pourrait fortement être diminuée par la présence de CO2, empêchant l'hydratation de l'olivine durant extraction des xénolites par les kimberlites. Ces résultats expérimentaux suggèrent que les teneurs en hydrogène dans l'olivine des péridotites du craton du Kaapvaal ont été acquises durant un épisode métasomatique en profondeur et non pendant leur extraction par les kimberlites. Ces teneurs n'ont toutefois pas à ce jour entraîné de remobilisation de la racine cratonique. Enfin, le calcul des propriétés sismiques des péridotites cratoniques révèle que les anisotropies générées par les OPRs de ces échantillons sont suffisantes pour expliquer les anisotropies mesurées par les ondes SKS et les ondes de surface.Les xénolites de la Divergence Nord-Tanzanienne, montrent des variations significatives de microstructures et d'OPR de l'olivine entre les péridotites des localités dans l'axe du rift et celles de la chaîne volcanique transverse (Lashaine et Olmani). A Lashaine, les microstructures granulaires à gros grains et les OPRs de type orthorhombique et axial-[010] peuvent être expliquée par une déformation en transpression liée à la formation de la chaîne Mozambique ou par la présence d'une relique d'un domaine cratonique à l'intérieur de la chaîne Mozambique. Dans l'axe du rift, les microstructures porphyroclastiques à mylonitiques suggèrent une déformation plus récente, accompagnée de réactions magma-roche sous des conditions proches du solidus, suivie d'un recuit variable. L'hétérogénéité des microstructures enregistrées par les échantillons du rift suggère de multiples épisodes de déformation localisée, probablement liés à l'injection percolation épisodique de magmas, espacés de périodes d'accalmie. Les OPRs de l'olivine de type axial-[100] et l'orientation des directions de polarisation des ondes SKS suggère que le rift s'est formé en régime de transtension Les péridotites du Sud-Est de l’Éthiopie présentent des microstructures porphyroclastiques à gros grains moins recristallisées qu'en Tanzanie. Les microstructures et les OPRs principalement de type orthorhombique suggèrent une déformation syn- à post-métasomatisme. Les anisotropies de polarisation des ondes S calculées pour ces échantillons sont insuffisantes pour expliquer à elles seules les déphasages des ondes SKS dans cette partie du rift.
https://tel.archives-ouvertes.fr/tel-01684759

Droits : info:eu-repo/semantics/OpenAccess
NNT : 2014MON20139
tel-01684759
https://tel.archives-ouvertes.fr/tel-01684759
https://tel.archives-ouvertes.fr/tel-01684759/document
https://tel.archives-ouvertes.fr/tel-01684759/file/43443_BAPTISTE_2014_archivage_cor.pdf

Éditeur(s) : HAL CCSD Station Biologique
Résumé : International audience
This study deals with temporal variations in eel diet Anguilla anguilla sampled at each of the four seasons in the Languedocian Prévost lagoon (Gulf of Lion) from Autumn 1998 to Summer 1999. The following feeding indices were calculated based on observations of 12 categories of prey found in the contents of full stomachs: coefficient of vacuity CV, degree of fullness DR, occurrence frequency PP, relative abundance N (in %) and relative weight P (in %). The interpretation of results is also based on the Costello's method (1990) which combines PP and N. Anguilla anguilla mainly feeds on benthic organisms, primarily Gammarus gr. locusta, Polychaeta, insect larvae, small fish. Based on variations in eel diet, seasonal influence is illustrated by a decrease in feeding activity in summer which gradually increases during the following seasons. The good trophic quality available to eels in the Prévost lagoon depends on its hydrodynamics which is directly related to the movement of water entering and leaving lagoon by a short communication with the sea. This water movement accelerates the enrichment and production processes of this ecosystem. Changes observed during the four seasons illustrate an opportunistic type of feeding behaviour. Eels consume the most available benthic prey. They favour the importance of the prey at a given moment without using a particular feeding strategy like specialisation or generalisation. Thus, eel adapts its diet in adjusting available energy resources in the ecosystem. Because of this, the lagoon-resident species Anguilla anguilla is an obvious indirect bioindicator of the trophic capacity and present level of confinement in the brackish water lagoon ecosystem of Prévost.
ISSN: 0007-9723

hal-00753021
https://hal.univ-antilles.fr/hal-00753021

Éditeur(s) : HAL CCSD
Résumé : International audience
The subterranean environment is often described as “extreme” and food poor. Laboratory experiments have shown that blind Mexican tetra Astyanax mexicanus (De Filippi, 1853) cavefish are better at finding food in the dark than surface fish. Several morphological and behavioural attributes that could foster this obvious adaptive response to cave environments have been described. Nonetheless, it is currently unknown what young cavefish actually eat in their natural cave environment. Our results from the Pachón cave in México during the dry and rainy season show that fry are efficient predators in their natural cave environment. Their primary food item is aquatic crustaceans. The guts of post-larval, pre-juvenile stage individuals (n=9) contained an average of 17.9 water fleas (Cladocera), copepods, ostracods, and isopods. Thus, the fry in this cave are well-fed. The Pachón cave environment does not appear to be “food poor” for juvenile cavefish. Food regimes change between post-larval and adult stages to become more dependent on partially decomposed material, guano, or detritus from the mud. We discuss the data with regards to our current developmental and genetic understanding of cavefish morphological and behavioural evolution, particularly regarding its enhanced Vibration Attraction Behaviour (VAB).
Subterranean Biology

hal-01432027
https://hal.archives-ouvertes.fr/hal-01432027
DOI : 10.3897/subtbiol.21.11046

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Urucum region (Mato Grosso do Sul, Brazil) contains Neoproterozoic–Cambrian manganese ore in the layers Mn-1, Mn-2, and Mn-3, which are interbedded with iron formations (IFs) from the Santa Cruz Formation (Jacadigo Group) and surrounded by carbonate rocks from the Bocaina and Tamengo Formations (Corumbá Group). These rocks fill an ancient graben, with sediments from the Santa Cruz Formation overlying fluvial deposits from the Urucum Formation and limestones from the Bocaina and Tamengo Formations deposited in the shallow marginal regions. As the graben deepened, it was flooded with microbe-rich seawater and hydrothermalism began. Iron and manganese precipitated within the pores in arkosic sandstones, thereby forming the clastic Lower Mn-1 ore layer. The remaining manganese was simultaneously deposited on the basin floor with clastic clay and silt from turbidity currents, thereby forming the Upper Mn-1 clastic–chemical ore layer. The sedimentation of Mn-1 and its host IFs was controlled by seawater saturation and homogeneous oxidation, which caused manganese and iron sedimentation and the death of microorganisms, generating mangano-ferriferous sediments with high P, Co and Ni contents. Mn-2 formed during periods of tectonic quiescence through water influxes that carried abundant microbes, Fe(II), Mn(II), and SiO2. Under UV radiation, these microbes oxidized Mn(II) and Fe(II) to form hydroxides and died, thereby forming biomass that was enriched in P, Co and Ni and minor carbonate adjacent to and below the oxycline. These microbes also formed kremydilites, oblate structures that resemble manganese stromatolites, within the biomass and produced CH4 and/or H2 gas bubbles. During early diagenesis, wormlike organisms inhabited the biomass and probably separated iron from manganese to produce cryptomelane microbialites, which agglutinated to form manganese micronodules that coalesced to form the massive layer Mn-2. This process ended with the disappearance of microorganisms and the sedimentation of the IFs, and a new water influx generated layer Mn-3 via the same process. The final seawater upwelling precipitated IFs in the basin depocenter, whereas limestone from the Tamengo Formation was deposited along the basin’s edges. The diagenesis initially transformed the manganese oxides into cryptomelane and then into hollandite.
ISSN: 0169-1368

hal-01684668
https://hal.archives-ouvertes.fr/hal-01684668
DOI : 10.1016/j.oregeorev.2017.09.018

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
We have analyzed the microstructures and crystal preferred orientations (CPO), and calculated the seismic properties of 53 mantle xenoliths from four localities within the North Tanzanian Divergence of the East African rift: two within the rift axis and two in the transverse volcanic belt. Olivine OH concentrations were measured in 15 xenoliths.Most samples have harzburgitic to dunitic compositions and high olivine Mg#. Microstructures and olivine CPO patterns vary strongly depending on the location. In-axis peridotites display mylonitic to porphyroclastic microstructures, which record recent deformation by dislocation creep. Highly stretched orthopyroxenes in mylonites indicate that the deformation was initiated under high stress and probably low temperature. Orthopyroxene replacement by olivine in mylonitic and porphyroclastic peridotites suggest syn-kinematic melt–rock reactions and further deformation under near-solidus conditions. Exsolutions in orthopyroxene imply significant cooling between melt-assisted deformation and xenolith extraction. Late metasomatism is evidenced by the occurrence of veins crosscutting the microstructure and interstitial clinopyroxene and phlogopite. Axial-[100] olivine CPOs predominate, suggesting activation of the high temperature, low pressure [100] {0kl} slip systems and, probably, transtensional deformation. In the volcanic belt, Lashaine peridotites display very coarse-granular textures, indicating deformation by dislocation creep under low deviatoric stress conditions followed by annealing. Axial-[010] olivine CPOs are consistent with transpressional deformation or simultaneous activation of the [100](010) and [001](010) slip systems. Intermediate microstructures and CPOs in Olmani suggests heterogeneous deformation within the volcanic belt. Olivine OH concentrations range between 2 and 12 ppm wt. H2O. No systematic variations are observed between in- and off-axis samples. Maximum P wave azimuthal anisotropy (AVp) ranges between 3.3 and 18.4%, and the maximum S wave polarization anisotropy (AVs) between 2.3 and 13.2%. Comparison between seismic properties of in-axis peridotites and SKS splitting data suggests transtensional deformation in the lithospheric mantle beneath the rift.
ISSN: 0040-1951

hal-01121552
https://hal.archives-ouvertes.fr/hal-01121552
DOI : 10.1016/j.tecto.2014.11.011

Éditeur(s) : HAL CCSD
Résumé : International audience
This study aims at introducing a method for determining the dielectric properties of lossy materials with high water contents in a millimetre-wave reverberation chamber. Such materials with high water content, e.g. biological tissues can be described by a Debye model. The proposed method consists in fitting the theoretical average absorption cross section to the experiment data resulting from the average absorption cross section measurements. By applying this method on a 4% agar phantom in the 50-65 GHz frequency range, it is demonstrated that the permittivity and conductivity of biological tissues can be determined at millimeter waves using reverberation chamber. The difference between the measured real and imaginary parts and the reference value of the agar phantom is 4.3% and 8%, respectively.
BIOEM 2016
Gand, Belgium

hal-01377570
https://hal.archives-ouvertes.fr/hal-01377570
https://hal.archives-ouvertes.fr/hal-01377570/document
https://hal.archives-ouvertes.fr/hal-01377570/file/bioem%202016_1_final.pdf

Éditeur(s) : HAL CCSD Elsevier Masson
Résumé : In French Guiana, the population growth will result in an increase in demand for agricultural products and thus, will lead to an increase in the amount of tropical forests converted into cropland or pasture. Impacts of different agricultural systems on greenhouse gas (GHG) fluxes have not been studied in French Guiana. In this context, the fire-free chop-and-mulch method was used to convert a tropical forest site to agriculture. This study focused on soil nitrous oxide (N2O) emissions and we compared four land uses: (1) the undisturbed tropical forest, (2) recently converted grassland and recently converted croplands (fertilized soybean/maize rotation) with either (3) disk tillage or (4) no tillage.N2O measurements were obtained through the chamber technique and conducted over a 1-year period (measurements began 19 months after the forest was cleared). N2O fluxes were related to soil parameters measured at each sampling date: nitrate and ammonium contents, gravimetric water content (GWC) and temperature.Through the entire period, the mean (±standard error) and median N2O fluxes were 3.8 ± 0.5 and 2.7 g N ha−1 day−1, respectively for undisturbed tropical forest and 2.4 ± 0.9 and 0.8 g N ha−1 day−1, respectively for grassland (mowed Brachiaria ruziziensis). For croplands, no significant difference was found for N2O emissions between both agricultural practices. The mean (±standard error) and median N2O fluxes were 8.5 ± 1.2 and 4.0 g N ha−1 day−1, respectively for disk tillage plots and 8.5 ± 1.3 and 3.6 g N ha−1 day−1, respectively for no tillage plots. Nitrogen inputs (due to the application of fertilizer or due to the mineralization of crop residues) led to higher N2O fluxes, resulting in significantly higher mean N2O emissions from croplands compared to the forest, when only considering land use effect on N2O fluxes in a statistical model. The soil nitrate content, GWC and temperature had a significant positive effect on N2O fluxes. Taking into account these soil parameters in another statistical model, N2O emissions from croplands were not higher than the natural N2O emissions from tropical forest soils. Our results suggest that, if more forest will have to be converted in the course of the expected population growth in French Guiana, it could have low impact on the soil N2O fluxes (similar to natural fluxes from forest) with the improving of farming techniques (for example modification of the splitting of N-fertilizer) in the cropping plots.
ISSN: 0167-8809

hal-01204228
https://hal.archives-ouvertes.fr/hal-01204228
DOI : 10.1016/j.agee.2015.04.004
PRODINRA : 307607

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Almost all Red Sea deeps contain metal-rich sediments covered by brine pools. It is generally agreed that these metal-rich deposits precipitated from overlying metal-rich brines that originated from migrating hydrothermal fluids. No brine pool has ever been reported in Thetis Deep, inciting us to evaluate if such a brine layer ever occurred in the deep during the past. In order to address that questioning, a study combining mineralogical, geochemical (major-, minor-, rare-earth elements) and isotopic (Sr. Nd. Pb) approaches was completed on cored sediments and extracted interstitial waters from inside and outside the deep.;The sediments have an overall hydrothermal origin, as shown by the REE concentrations and patterns, metal contents, and Pb-Nd isotopic data, all pointing to a mantle signature. The intensity of the hydrothermal activity varied with time in the deep; the most intense episode resulting in an almost pure Fe-oxi-hydroxide layer. Varied chemical arguments, especially the Zr and REE data of the sediments, favor the fact that the whole sedimentation in Thetis Deep occurred in the absence of a stable, salt-rich and mineralized brine pool, and that no brine layer ever existed. This conclusion is supported by the constant Sr isotope composition of the sediment and its interstitial waters that are almost identical to that of the Red Sea seawater. The study also suggests that hydrothermal activity monitored fluid supplies that interacted differently with seawater in the different Red Sea deeps, resulting in an overall formation of metal-rich sediments, but along varied local conditions. (C) 2009 Elsevier B.V. All rights reserved.
ISSN: 0375-6742

hal-00475646
https://hal.archives-ouvertes.fr/hal-00475646
DOI : 10.1016/j.gexplo.2009.10.001

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This study reports petrostructural observations in the pargasite and phlogopite-bearing Finero peridotite massif (Italian Western Alps), which suggest that the pervasive foliation in this massif was formed by deformation concomitant with percolation of hydrous Si-rich melts: (1) diffuse contacts, but systematic parallelism between the pyroxenitic layers and the foliation of the peridotite (2) strong shape and crystal preferred orientations (SPO and CPO), but subhedral or interstitial shapes and weak intracrystalline deformation of the hydrous phases, (3) CPO, but interstitial shapes of the pyroxenes, (4) very coarse olivine grain sizes, which are correlated to the olivine abundance, and (5) elongated shapes, but weak intracrystalline deformation, and extremely weak and highly variable CPO of olivine. The pervasive deformation of the Finero peridotite occurred therefore under conditions that allowed coexistence of H2O–CO2-bearing melts, pargasite, and spinel, that is, temperatures of 980–1080 °C and pressures <2 GPa. The petrostructural observations suggest that the presence of hydrous melts results in accommodation of large amounts of deformation by stress-controlled dissolution–precipitation and advective transport of matter by the melts and in fast grain boundary migration in olivine. By consequence, it produces significant rheological weakening. Water contents in olivine are <4 ppm wt., implying limited contribution of hydration of olivine to weakening. In addition, the analysis of protomylonites composing the external domains of the shear zones that overprint the pervasive foliation indicates that the transition to melt-free conditions results in enhanced contribution of dislocation creep to the deformation. The associated increase of the peridotites' strength leads to onset of strain localization. The latter is not correlated to the local abundance in pargasite or phlogopite, implying that crystallization of amphiboles or phlogopite, even at concentrations of 25 vol.%, does not produce rheological weakening in the upper mantle.
ISSN: 0012-821X

hal-01667879
https://hal.archives-ouvertes.fr/hal-01667879
DOI : 10.1016/j.epsl.2017.08.015

Éditeur(s) : HAL CCSD Cambridge University Press
Résumé : International audience
Background: Most of the 29 Siganidae species are widely distributed through the Indo-Pacific area. In New Caledonia, these family was represented by 12 species. The present report is the first record of Siganus randalli in New Caledonian waters and provide information on its diet. Methods: Three specimens of Siganus randalli were caught in shallow mangrove waters of the southern part of New Caledonia. Their stomach contents and isotopic signatures (carbon and nitrogen) were analyzed and compared to others siganids species. Results and conclusion: This note provides the most southerly record of the rabbitfish Siganus randalli, which extends its distribution range by 1200 km southward and 1300 km southwest. The data on its diet, when compared with other co-occurring or more reef-associated siganid species, provide information on feeding processes and ecological functions associated with its mangrove habitat.
EISSN: 1755-2672

Droits : http://creativecommons.org/licenses/by/
hal-01369012
http://hal.upmc.fr/hal-01369012
http://hal.upmc.fr/hal-01369012/document
http://hal.upmc.fr/hal-01369012/file/art_10.1186_s41200-016-0082-x.pdf
DOI : 10.1186/s41200-016-0082-x

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The Oman ophiolite includes both a fossil fast spreading axis, defined by five mantle diapirs, and an off-axis mantle diapir emplaced 30 km from the axis, providing a natural laboratory for the study of off-axis magmatic processes. We compare field and petrological observations coupled with geochemical and isotopic analyses of samples from the off-axis diapir with those of the nearest on-axis diapir, with a particular focus on the Moho Transition Zone (MTZ). Both diapirs are defined by the presence of steeply plunging lineations, but in the on-axis case, these lineations rotate gradually into parallelism with the horizontal magmatic lineations of the overlying crust, while in the off-axis case, a shear zone separates the steeply plunging lineations from the horizontal lineations of the surrounding mantle. In the on-axis diapir, the MTZ is 50 to 500 m thick and composed of dunite with layered gabbro lenses whereas in the off-axis diapir, the MTZ is thicker and composed of dunite with massive (∼20% of MTZ) clinopyroxenite lenses and a notable absence of plagioclase. Moreover, the off-axis diapir is associated with amphibole-bearing intrusions, consisting of Mg-rich gabbroic sills in the mantle peripheral to the diapir, and microgabbroic lenses of broadly basaltic composition in the overlying crust. The ε Nd values of the pyroxenites in the MTZ of the off-axis diapir fully overlap with those of the intrusions in the surrounding mantle and crust, suggesting that they are genetically related. Calculated rare earth element (REE) abundances of liquids in equilibrium with clinopyroxene imply that the magmas that traversed the MTZ of the off-axis diapir were more depleted in highly incompatible elements than their counterparts in the MTZ of the on-axis diapir. On the other hand, Nd isotopic compositions of the off-axis samples (εNd=6.2–7.9εNd=6.2–7.9 in 18 of 19 samples) indicate derivation of their parental magmas from a less depleted source than that which produced the magma associated with the on-axis gabbro (εNd=7.8–9.2εNd=7.8–9.2, 10 analyses).To explain these observations, we suggest that the earliest magmas in the uprising off-axis diapir formed from the partial melting of pyroxenite veins with less radiogenic Nd isotopic compositions than those of the ambient peridotite. As the diapir traversed the cool, hydrated lithosphere these early melts interacted with depleted harzburgites, lowering the incompatible element contents of the melt products while having little effect on their Nd isotopic compositions. The great abundance of clinopyroxene in the off-axis MTZ might be explained by the high pyroxene component in the original melt but perhaps also by the presence of water in the lithosphere, which would favor the crystallization of clinopyroxene while inhibiting that of plagioclase. The intrusions in the overlying crust could represent, to first order, the secondary melts produced by the melt–harzburgite reaction, while the sills in the surrounding mantle may be cumulates from such secondary melts.These results shed light on processes occurring during interaction between rising off-axis material and depleted, hydrated lithospheric mantle. Furthermore, if our interpretation is correct, the low εNd values of the off-axis samples contribute to the growing body of evidence for the presence of pyroxenite veins in the MORB mantle source.
ISSN: 0012-821X

hal-01306575
https://hal.archives-ouvertes.fr/hal-01306575
DOI : 10.1016/j.epsl.2015.12.005