Consulta: subjectFacets:"Boron isotopes"
Registros recuperados: 3
Data/hora: 06/06/2024 10:13:04

Correlation of boron isotopic composition with ultrastructure in the deep- sea coral Lophelia pertusa: Implications for biomineralization and paleo-pH
Provedor de dados: 5
Autores: Blamart, D.; Rollion-bard, C.; Meibom, A.; Cuif, J. -p.; Juillet-leclerc, A.; Dauphin, Y.
Using the CRPG-CNRS Cameca 1270 ion microprobe facility, we have measured boron isotopic compositions (B-11/B-10) in different ultrastructural components of the deep-sea aragonitic scleractinian coral Lophelia pertusa. We observe a systematic difference in B isotopic composition between the Early Mineralization Zone ( EMZ) and adjacent fibrous skeleton. In EMZ the measured delta(11) B values are consistently low. Fibrous aragonite is characterized by systematically higher delta(11) B values but also displays B isotopic heterogeneity associated with specific growth bands in the calyx wall. The magnitude of the observed B isotopic variations cannot be explained by changes in environmental conditions and is likely caused by biological processes involved in...
Tipo: Text
Palavras-chave: Boron isotopes; Deep-sea coral; Biomineralization; Aragonite; Microstructure; PH.
Ano: 2007
URL: https://archimer.ifremer.fr/doc/00235/34641/33060.pdf

In situ Lithium and Boron isotope determinations in mica, pyroxene, and serpentine by LA-MC-ICP-MS
Provedor de dados: 5
Autores: Marti, Celine; Ponzevera, Emmanuel; Harlow, George.
Boron and Li are light, incompatible elements that preferentially partition into the liquid phase, whether melt or aqueous fluid, and thus are useful for tracking fluid-related processes in rocks. Most of the Li isotopic data presently available on subduction-related rocks are from whole-rock analyses; and the B isotopic analyses of subduction material have been carried out either on whole-rocks or in-situ on an accessory phase, such as tourmaline. The new method presented here couples an ESI New Wave UP-193-FX ArF* (193 nm) excimer laser-ablation microscope with a Neptune Plus (Thermo Scientific) MC-ICP-MS aiming to measure both Li and B isotopes in situ with good spatial resolution (metamorphic minerals are commonly chemically zoned, and whole-rock...
Tipo: Text
Palavras-chave: Boron isotopes; Lithium isotopes; LA-MC-ICP-MS; Subduction zone related silicates.
Ano: 2015
URL: http://archimer.ifremer.fr/doc/00274/38533/37050.pdf

Geochemistry and δ11 B evolution of tourmaline from tourmalinite as a record of oceanic crust in the Tonian Ibaré ophiolite, southern Brasiliano Orogen
Provedor de dados: 42
Autores: ARENA,KARINE DA ROSA; HARTMANN,LÉO AFRANEO; LANA,CRISTIANO DE CARVALHO; QUEIROGA,GLÁUCIA NASCIMENTO; CASTRO,MARCO PAULO DE.
Abstract  The isotopic and geochemical evolution of tourmaline constrain the processes of paleo-oceanic lithosphere in ophiolites. The Brasiliano Orogen is a major structure of South America and requires characterization for the understanding of Gondwana supercontinent evolution. We made a pioneering investigation of tourmaline from a tourmalinite in the Ibaré ophiolite by integrating field work with chemical analyses of tourmaline by electron microprobe (EPMA) and δ11B determinations via laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS). Remarkably massive tourmalinite (&gt;90 vol.% tourmaline, some chlorite) enclosed in serpentinite has homogeneous dravite in chemical and isotopic composition (δ11B = +3.5 to +5.2‰). These results...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Boron isotopes; Geochemistry; Ibaré ophiolite; Tourmalinite; Southern Brasiliano Orogen.
Ano: 2020
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652020000100603