Manganese incorporation in synthetic hercynite, and partitioning between hercynite and silicate melt synthesized at 1.0 GPa, 1250°C, and at an f O2 buffered by Fe-FeO, has been studied by X-ray absorption spectroscopy and single-crystal X-ray structure refinement. Spectra indicate the presence of both Mn2+ and Mn3+ (and possibly also Mn4+) in synthetic hercynite and partitioning of Mn2+ into the melt phase, and Mn3+ into hercynite, respectively, under run conditions. X-ray refinement is consistent with partial disorder of Fe and Al across tetrahedral and octahedral sites. A higher than expected degree of Fe-Al disorder in the Mn-bearing hercynite can be explained by preferential incorporation of Mn2+ onto the tetrahedral site, and indicates that Fe-Al disorder in pure, stoichiometric hercynite cannot necessarily be used to determine closure temperatures in natural spinel. However, partitioning of Mn2+ and Mn3+ between melt and hercynite suggests that Mn incorporation in hercynite could be used as a measure of f O2 conditions in magmas during spinel crystallization.

Manganese incorporation in synthetic hercynite / G.D. Bromiley, G.D. Gatta, T. Stokes. - In: MINERALOGICAL MAGAZINE. - ISSN 0026-461X. - 79:3(2015), pp. 635-647. [10.1180/minmag.2015.079.3.09]

Manganese incorporation in synthetic hercynite

G.D. Gatta
Secondo
;
2015

Abstract

Manganese incorporation in synthetic hercynite, and partitioning between hercynite and silicate melt synthesized at 1.0 GPa, 1250°C, and at an f O2 buffered by Fe-FeO, has been studied by X-ray absorption spectroscopy and single-crystal X-ray structure refinement. Spectra indicate the presence of both Mn2+ and Mn3+ (and possibly also Mn4+) in synthetic hercynite and partitioning of Mn2+ into the melt phase, and Mn3+ into hercynite, respectively, under run conditions. X-ray refinement is consistent with partial disorder of Fe and Al across tetrahedral and octahedral sites. A higher than expected degree of Fe-Al disorder in the Mn-bearing hercynite can be explained by preferential incorporation of Mn2+ onto the tetrahedral site, and indicates that Fe-Al disorder in pure, stoichiometric hercynite cannot necessarily be used to determine closure temperatures in natural spinel. However, partitioning of Mn2+ and Mn3+ between melt and hercynite suggests that Mn incorporation in hercynite could be used as a measure of f O2 conditions in magmas during spinel crystallization.
hercynite; spinel; manganese; oxygen fugacity; disorder; crystal chemistry
Settore GEO/09 - Georisorse Miner.Appl.Mineral.-Petrogr.per l'amb.e i Beni Cul
2015
Article (author)
File in questo prodotto:
File Dimensione Formato  
Hercynite_MinMag.pdf

accesso riservato

Tipologia: Publisher's version/PDF
Dimensione 512.12 kB
Formato Adobe PDF
512.12 kB Adobe PDF   Visualizza/Apri   Richiedi una copia
Manganese incorporation in synthetic hercynite.pdf

accesso aperto

Descrizione: Versione accettata dall'editore per la stampa
Tipologia: Post-print, accepted manuscript ecc. (versione accettata dall'editore)
Dimensione 218.05 kB
Formato Adobe PDF
218.05 kB Adobe PDF Visualizza/Apri
Pubblicazioni consigliate

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/321619
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 4
social impact