Titanomagnetite – Silicate Melt Oxybarometry

Robert, Aymeric; Audétat, Andreas

doi:10.1002/9781119473206.ch18

Cited by 1 publication

(1 citation statement)

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“…Vanadium also becomes more compatible under more reducing conditions, reflected in the partition coefficients; with decreasing oxygen fugacity, D cpx V increases from 0.9 to 8.5, D ilm V from 7.0 to 17.4, and V is the most compatible in magnetite, ranging from 7.1 to 32.9. This can be explained by the flexible crystal structure of magnetite which permits the accommodation of a range of cations (Righter et al 2006a; Arató and Audétat 2021); the similar ionic radii of V 3+ (0.65 Å) and V 4+ (0.61 Å) to Fe 3+ (0.67 Å) and Ti 4+ (0.64 Å) allows V to become strongly concentrated in magnetite (Arató and Audétat 2021). The relationship between D V and fO 2 for our experimental data, corroborated by literature data, is illustrated in Fig.…”

Section: Mineral−melt Partition Coefficientsmentioning

confidence: 99%

Trace element partitioning between clinopyroxene, magnetite, ilmenite and ferrobasaltic to dacitic magmas: an experimental study on the role of oxygen fugacity and melt composition

Shepherd

Namur

Toplis

et al. 2022

Contrib Mineral Petrol

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Ilmenite-, magnetite-and clinopyroxene−melt trace element partition coefficients were investigated experimentally as a function of oxygen fugacity and melt composition in a range of synthetic ferrobasaltic bulk compositions. The experiments were performed at a constant temperature (1080 °C) and pressure (1 atm) over a range of oxygen fugacity (fO 2 ) conditions from ca. 2 log units below to ca. 2 log units above the FMQ buffer. The partitioning behaviour of the divalent cations Zn, Mn, Co and Ni are found to be controlled by the degree of polymerisation of the coexisting melt; the partitioning behaviour of rare earth elements, Y and Sc can be explained well by the lattice strain model and the partitioning of the high-field strength elements Zr, Hf, Ta and Nb is influenced by the TiO 2 content of the melt. Vanadium partitioning is strongly influenced by oxygen fugacity and a series of linear regression equations are presented to express the dependence of the mineral−melt partitioning behaviour of the multivalent cation V on oxygen fugacity. Furthermore, calibration of the partitioning of vanadium between magnetite-ilmenite pairs as an oxybarometer is proposed and applied to a ferrobasaltic layered intrusion-the Skaergaard intrusion-to provide an estimate of oxygen fugacity.

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Section: Mineral−melt Partition Coefficientsmentioning

confidence: 99%