Magma hybridisation and diffusive exchange recorded in heterogeneous glasses from Soufrière Hills Volcano, Montserrat

Humphreys, M. C. S. and Edmonds, M. and Christopher, T. and Hards, V. (2010) Magma hybridisation and diffusive exchange recorded in heterogeneous glasses from Soufrière Hills Volcano, Montserrat. Geophysical Research Letters, 37. 6 PP.. DOI 10.1029/2009GL041926

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Abstract

Arc volcanoes commonly show evidence of mixing between mafic and silicic magma. Melt inclusions and matrix glasses in andesite erupted from Soufrière Hills Volcano, Montserrat, include an anomalously K2O-rich population which shows close compositional overlap with residual glass from mafic inclusions. We suggest that these glasses represent the effects of physical mixing with mafic magma, both during ascent and by diffusive exchange during the formation of mafic inclusions. Many glasses are enriched only in K2O, suggesting diffusive contamination by high-K mafic inclusion glass; others are also enriched in TiO2, suggesting physical mixing of remnant glass. Some mafic inclusion glasses have lost K2O. The preservation of this K-rich melt component in the andesite suggests short timescales between mixing and ascent. Diffusive timescales are consistent with independent petrological estimates of magma ascent time.

Item Type: Article
Uncontrolled Keywords: 2010AREP; IA61;
Subjects: 05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Divisions: 05 - Petrology - Igneous, Metamorphic and Volcanic Studies
Journal or Publication Title: Geophysical Research Letters
Volume: 37
Page Range: 6 PP.
Identification Number: 10.1029/2009GL041926
Depositing User: Sarah Humbert
Date Deposited: 21 Jul 2010 09:31
Last Modified: 23 Jul 2013 09:57
URI: http://eprints.esc.cam.ac.uk/id/eprint/1476

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