The Role of Redox Processes in Determining the Iron Isotope Compositions of Minerals, Melts, and Fluids - Archive ouverte HAL Accéder directement au contenu
Chapitre D'ouvrage Année : 2021

The Role of Redox Processes in Determining the Iron Isotope Compositions of Minerals, Melts, and Fluids

Paolo A Sossi
  • Fonction : Auteur
Baptiste Debret

Résumé

Stable isotope fractionation is a response to the minimisation of free energy associated with differences in vibrational frequencies during substitution of isotopic masses between two phases. Site properties are dictated by the bonding environment of iron, and influence its 'force constant', a descriptor for bond strength. Because iron readily transitions between its ferrous (Fe 2+) and ferric (Fe 3+) state over the oxygen fugacities (fO 2) of terrestrial magmas, redox processes are presumed to control iron isotope fractionation. In fact, both coordination and redox state are key to interpreting iron isotope variations in high-temperature, high-pressure geological systems. Determinations of iron force constants by experimental, theoretical and spectroscopic means in minerals, melts and fluids are reviewed, emphasising the effect of composition in influencing isotopic fractionation. Within this framework, the application of numerical models of partial melting to iron isotope variations in oceanic basalts and subduction-zone (or arc) magmas has shed light on their genesis. The influence of melt composition, mineral mode and fluid exsolution in producing iron isotope fractionation in evolving magmas is explored. Iron isotopic signatures in magmatic rocks are linked to that of their sources, and are influenced by the iron isotopic evolution of subducting slabs and transfer of fluids to the mantle wedge.
Fichier principal
Vignette du fichier
Sossi_Debret_2021.pdf (1.59 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03368395 , version 1 (20-10-2021)

Identifiants

  • HAL Id : hal-03368395 , version 1

Citer

Paolo A Sossi, Baptiste Debret. The Role of Redox Processes in Determining the Iron Isotope Compositions of Minerals, Melts, and Fluids. Magma Redox Geochemistry, 2021, 978-1-119-47325-1. ⟨hal-03368395⟩
43 Consultations
172 Téléchargements

Partager

Gmail Facebook X LinkedIn More