Distribution of dissolved water in magmatic glass records growth and resorption of bubbles

I.M. McIntosh, E.W. Llewellin, M.C.S. Humphreys, A.R.L. Nichols, A. Burgisser, C.I. Schipper, J.F. Larsen
2014 Earth and Planetary Science Letters  
2014) 'Distribution of dissolved water in magmatic glass records growth and resorption of bubbles.', Earth and planetary science letters., 401 . pp. 1-11. Further information on publisher's website: The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made
more » ... the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full DRO policy for further details. Available online xxxx Editor: T. Elliott Keywords: bubble growth bubble resorption diffusion quench effect water speciation disequilibrium Volcanic eruptions are driven by the growth of gas bubbles in magma. Bubbles grow when dissolved volatile species, principally water, diffuse through the silicate melt and exsolve at the bubble wall. On rapid cooling, the melt quenches to glass, preserving the spatial distribution of water concentration around the bubbles (now vesicles), offering a window into pre-eruptive conditions. We measure the water distribution around vesicles in experimentally-vesiculated samples, with high spatial resolution. We find that, contrary to expectation, water concentration increases towards vesicles, indicating that water is resorbed from bubbles during cooling; textural evidence suggests that resorption occurs largely before the melt solidifies. Speciation data indicate that the molecular water distribution records resorption, whilst the hydroxyl distribution records earlier decompressive growth. Our results challenge the emerging paradigm that resorption indicates fluctuating pressure conditions, and lay the foundations for a new tool for reconstructing the eruptive history of natural volcanic products.
doi:10.1016/j.epsl.2014.05.037 fatcat:3j3oxt7c7jh3hdklkp2nomeb74