Large vesicles record pathways of degassing at basaltic volcanoes
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Volcanic degassing is directly linked to magma dynamics and controls the style of eruptive activity. To better understand how gas is transported within basaltic magma we perform a 3D investigation of vesicles preserved in scoria from the 2005 activity at Stromboli volcano (Italy). We find that clasts are characterized by the ubiquitous occurrence of one to a few large vesicles, exhibiting mostly irregular, tortuous, channel-like textures, orders of magnitude greater in volume than all the other vesicles in the sample. We compare observations on natural samples with results from numerical simulations and experimental investigations of vesicle size distributions and demonstrate that this type of vesicle invariably forms in magmas with vesicularities > 0.30 (and possibly > 0.10). We suggest that large vesicles represent pathways used by gas to flow non-explosively to the surface and that they indicate the development of an efficient system that sustains persistent degassing in basaltic systems.
KeywordsBasaltic magmas Degassing 3D vesicle textures
We thank the SYRMEP beamline of Elettra Sincrotrone Trieste, Stefano Favretto and Livia Colò for their help in the acquisition of tomographic images of natural samples and Mark Rivers of GeoSoilEnviroCARS, Advanced Photon Source, for his help with microtomography of the experimental samples. We also thank Daniele Andronico, Mauro Rosi and Mario Zaia for sample collection. Thoughtful reviews by N. Métrich and an anonymous reviewer greatly improved the manuscript. This work was supported by Istituto Nazionale di Geofisica e Vulcanologia and Dipartimento per la Protezione Civile, and NSERC Discovery grant to D.R.B.
- Abramoff MD, Magelhaes PJ, Ram SJ (2004) Image processing with ImageJ. Biophoton Int 11:36–42Google Scholar
- Andronico D, Caruso S, Cristaldi A, Del Carlo P (2005) Rapporto sulle ceneri emesse dal vulcano Stromboli nel semestre Gennaio-Giugno 2005. UFVG report Prot. Int. no. UFVG2005/72Google Scholar
- Andronico D, Cristaldi A, Del Carlo P (2006a) Caratterizzazione delle ceneri emesse dal vulcano Stromboli nel periodo Luglio-Dicembre 2005. UFVG report Prot. Int. no. UFVG2006/25Google Scholar
- Andronico D, Corsaro RA, Cristaldi A, Polacci M (2006b) Monitoring highly energetic Strombolian activity at Stromboli volcano (Aeolian Islands, Italy): the example of the 9 January 2005 explosive event. Geophys Res Abstr 8 02305Google Scholar
- Baker DR, Freda C (1999) Ising models of undercooled binary system crystallization: comparison with experimental and pegmatite textures. Am Mineral 84:725–732Google Scholar
- Bunde A, Havlin S (1991) Fractals and disordered systems. Springer, Berlin Heidelberg New YorkGoogle Scholar
- Burton MR, Mader HM, Polacci M (2007a) The role of gas percolation in quiescent degassing of persistently active basaltic volcanoes. Earth Planet Sci Lett, DOI 10.1016/j.epsl.2007.08.028
- Corsaro RA, Miraglia L (2005) Attività di monitoraggio petrologico Stromboli-I semestre 2005. UFVG report Prot. Int. no. UFVG2005/70Google Scholar
- Corsaro RA, Miraglia L (2006) Attività di monitoraggio petrologico:Stromboli-II semestre 2005. UFVG report Prot. Int. no. UFVG2006/027Google Scholar
- Stauffer D, Aharony A (1994) Introduction to percolation theory, revised second edition. Taylor and Francis, LondonGoogle Scholar