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Microstructural evolution of silicate immiscible liquids in ferrobasalts

Accepted version
Peer-reviewed

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Authors

Holness, MB 
Partridge, JL 
Charlier, B 

Abstract

An experimental study of the microstructural evolution of an immiscible basaltic emulsion shows that the Fe-rich liquid forms homogeneously nucleated droplets dispersed in a continuous Si-rich liquid, together with droplets heterogeneously nucleated on plagioclase, magnetite, and pyroxene. Heterogeneous nucleation is likely promoted by localised compositional heterogeneities around growing crystals. The wetting angle of Fe-rich droplets on both plagioclase and magnetite increases with decreasing temperature. Droplet coarsening occurs by a combination of diffusion-controlled growth and Ostwald ripening, with an insignificant contribution from coalescence. Characteristic microstructures resulting from the interaction of immiscible Fe-rich liquid with crystal grains during crystal growth can potentially be used as an indicator of liquid unmixing in fully crystallised natural samples. In magma bodies < ~10 m in size, gravitationally-driven segregation of immiscible Fe-rich droplets is unlikely to be significant.

Description

Keywords

Immiscibility, Nucleation kinetics, Droplet size distributions, Wetting angle, Ferrobasalt, Binodal

Journal Title

Contributions to Mineralogy and Petrology

Conference Name

Journal ISSN

0010-7999
1432-0967

Volume Title

174

Publisher

Springer Science and Business Media LLC

Rights

All rights reserved
Sponsorship
NERC (1634451)
NERC (NE/L002507/1)