An empirical model for the calculation of spinel-melt equilibria in mafic igneous systems at atmospheric pressure: 1. Chromian spinels

Ariskin, A. A.; Nikolaev, G. S.

doi:10.1007/s004100050156

Cited by 53 publications

(26 citation statements)

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“…Clues on the different crystallization conditions of titanomagnetites from lava fountains and lava flows are provided by the redox state of the system. We have estimated the oxygen fugacity of the magmatic suspension through the spinel-based oxygen barometer of Ishibashi (2013) derived from the formalism of Ariskin and Nikolaev (1996) for the Fe 2+ -Fe 3+ partitioning between spinel and mafic melt, and the model of Sack (1980) relating the Fe 3+ /Fe 2+ ratio and oxygen fugacity in silicate melt. Results indicate that lava fountains equilibrated at buffering conditions (i.e., NNO + 1) close to those estimated for the crystallization of Etnean magmas at depth (Armienti et al, 1994(Armienti et al, , 2004(Armienti et al, , 2013.…”

Section: The Cooling History Of Lava Fountains and Lava Flowsmentioning

confidence: 99%

Clinopyroxene and titanomagnetite cation redistributions at Mt. Etna volcano (Sicily, Italy): Footprints of the final solidification history of lava fountains and lava flows

et al. 2015

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Section: The Cooling History Of Lava Fountains and Lava Flowsmentioning

confidence: 99%

Clinopyroxene and titanomagnetite cation redistributions at Mt. Etna volcano (Sicily, Italy): Footprints of the final solidification history of lava fountains and lava flows

et al. 2015

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“…Calculated fO 2 for type II chondrules of Semarkona using the same olivine-iron metal-silicate melt (OSI) oxybarometer gives values in the range of 1 to -1.5 log units below the IW buffer curve (Yu and Hewins, 1998). Similarly, chromium solubility at chromite saturation (Roeder and Reynolds, 1991;Murck and Campbell, 1986;Ariskin and Nikolaev, 1996) together with sulfur solubility at sulfide saturation (Haughton et al, 1974;O'Neil and Mavrogenes, 2002) which are both dependent on oxygen fugacity, hint at redox conditions up to IW+1 for the formation of type IIA chondrules in ordinary chondrites.…”

Section: Redox Conditions During Chondrule Formationmentioning

confidence: 99%

Relationships between type I and type II chondrules: Implications on chondrule formation processes

Villeneuve

Libourel

Soulié

2015

Geochimica et Cosmochimica Acta

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Please cite this article as: Villeneuve, J., Libourel, G., Soulié, C., Relationships between type I and type II chondrules: Implications on chondrule formation processes, Geochimica et Cosmochimica Acta (2015), doi: http://dx.doi.org/ 10.1016/j.gca. 2015.03.033 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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“…These experimental studies have been used to develop thermodynamic and empirical models to relate the composition of chromian spinel to a melt composition, assuming equilibrium under a certain set of conditions (Sack & Ghiorso 1991, Allan 1992, Ariskin & Nikolaev 1996, Poustovetov 2000. The goal has been to use the composition of chromian spinel to infer its past history assuming equilibrium between crystal and melt.…”

Section: Composition Of Chromian Spinel and Of The Coexisting Meltmentioning

confidence: 99%

Growth Forms and Composition of Chromian Spinel in Morb Magma: Diffusion-Controlled Crystallization of Chromian Spinel

Roeder

Poustovetov

Öskarsson

2001

The Canadian Mineralogist

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Microphenocrysts of chromian spinel in glass from an East Pacific Rise lava and three Icelandic subglacial lavas show a variety of complex skeletal, hopper, vermiform and chain textures. These grains of chromian spinel are larger than those found in most basalts. Many crystals show significant zoning in Cr/(Cr + Al), and the variation in Cr/(Cr + Al) with respect to Fe 2+ /(Fe 2+ + Mg) is distinctive for each sample. The four samples are relatively primitive, with between 9 and 10 wt.% MgO in the glass. One very distinctive texture, a core surrounded by a vermiform rim, has been interpreted by a number of researchers as a reaction texture caused either by changes in pressure or magma mixing. The variety of chromian spinel textures, including the vermiform rim, has been duplicated in an experimental run using the sample from the East Pacific Rise. The sample was held at 1225°C for 67 hours and then cooled slowly over 8 hours to 1147°C. We conclude that the vermiform texture and the other chromian spinel textures in the experimental run and the lavas are growth textures and not reaction textures. The change in growth habit that produces the vermiform rim is interpreted as diffusion-controlled growth, leading to what metallurgists refer to as cellular growth. Chromian spinel is susceptible to diffusion-controlled growth because of the very large difference in concentration of Cr in the melt (0.02-0.06 wt.% Cr 2 O 3 ) and in chromian spinel (30-50 wt.% Cr 2 O 3 ) at equilibrium. Although the chromian spinel in the glass of each natural sample shows a large variation in Cr/(Cr + Al), and thus was not in equilibrium with the bulk melt, its Fe 2+ / (Fe 2+ + Mg) may have been close to equilibrium with the bulk melt before quenching. The chromian spinel crystallized over a span of hours to days before a rapid water quench upon eruption. The complex textures and zoning probably reflect the turbulent conditions during passage of the magma toward the Earth's surface.Keywords: chromian spinel, chromite, basalt, texture, vermiform, hopper, diffusion-controlled crystallization. SOMMAIREDes microphénocristaux de spinelle chromifère sont présents dans une matrice vitreuse d'une lave basaltique provenant de la ride Est-Pacifique et de trois échantillons de coulées mises en place sous un glacier en Icelande. Ces cristaux contiennent une variété de textures complexes en entonnoir, vermiformes et en chaînes; ils sont plus grossiers que ceux qui caractérisent la plupart des basaltes. Plusieurs cristaux montrent une zonation importante en Cr/(Cr + Al), qui varie de façon distincte avec Fe 2+ /(Fe 2+ + Mg) dans chaque échantillon. Les quatre échantillons sont relativement primitifs, le verre contenant entre 9 et 10% (poids) de MgO. On a généralement interprété la présence d'un coeur entouré d'un liseré vermiforme comme résultat d'une réaction suite à des changements en pression ou à un mélange de magmas. La diversité texturale du spinelle chromifère, y inclus la bordure vermiforme, a été reproduite dans un série d'expériences f...

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An empirical model for the calculation of spinel-melt equilibria in mafic igneous systems at atmospheric pressure: 1. Chromian spinels

Cited by 53 publications

References 0 publications

Clinopyroxene and titanomagnetite cation redistributions at Mt. Etna volcano (Sicily, Italy): Footprints of the final solidification history of lava fountains and lava flows

Clinopyroxene and titanomagnetite cation redistributions at Mt. Etna volcano (Sicily, Italy): Footprints of the final solidification history of lava fountains and lava flows

Relationships between type I and type II chondrules: Implications on chondrule formation processes

Growth Forms and Composition of Chromian Spinel in Morb Magma: Diffusion-Controlled Crystallization of Chromian Spinel

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