Conduit- to localized-scale degassing during plinian eruptions: Insights from major element andvolatile (cl and H2O) analyses within vesuvius ad 79 pumice

38Citations
Citations of this article
69Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

Textural investigations of the AD 79 Vesuvius pumice emphasize the complexity of magma degassing and crystallization during the eruption, which emitted two types of pumice (white and gray) associated with different magma bodies of phonolitic and tephriphonolitic compositions respectively. These studies proposed that velocity gradients caused spatial variations in degassing within the ascending magma column at both the conduit and the localized scale.To validate this hypothesis, analyses of volatiles (Cl, H2O) and major elements in pumice glasses and melt inclusions were performed using high spatial resolution tools (microRaman spectrometry and electron microprobe) and combined with major element and volatile concentration profiles and maps. The results indicate that the melt phase differentiated through degassing-induced crystallization of leucite, and that the gray pumice magma was efficiently homogenized prior to degassing. Because Cl diffuses more slowly than H2O during fast ascent, it behaves as an incompatible element and can be used as a tracer of crystallization and H2O degassing. We emphasize the importance of strain localization in generating zones of preferential exsolution and permeable pathways for gases, and establish degassing scenarios that incorporate the effects of shear-zones. © The Author 2013. Published by Oxford University Press. All rights reserved.

Cite

CITATION STYLE

APA

Shea, T., Hellebrand, E., Gurioli, L., & Tuffen, H. (2014). Conduit- to localized-scale degassing during plinian eruptions: Insights from major element andvolatile (cl and H2O) analyses within vesuvius ad 79 pumice. Journal of Petrology, 55(2), 315–344. https://doi.org/10.1093/petrology/egt069

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free