Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/8287
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dc.contributor.authorallPolacci, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italiaen
dc.contributor.authorallBaker, D. R.; Earth and Planetary Sciences, McGill University, Montreal, QC H3A2A7, Canadaen
dc.contributor.authorallLa Rue, A.; Earth and Planetary Sciences, McGill University, Montreal, QC H3A2A7, Canadaen
dc.contributor.authorallMancini, L.; Sincrotrone Trieste S.C.p.A., 34149 Basovizza (Trieste), Italyen
dc.contributor.authorallAllard, P.; Institut de Physique du Globe, Paris Sorbonne Cité, CNRS UMR7154, Paris, Franceen
dc.date.accessioned2012-10-18T14:28:07Zen
dc.date.available2012-10-18T14:28:07Zen
dc.date.issued2012-07-01en
dc.identifier.urihttp://hdl.handle.net/2122/8287en
dc.description.abstractAmbrym is one of the most actively erupting basaltic volcanoes in the Vanuatu island arc. Scoria clasts collected from a fallout deposit in the inner terrace of its Benbow active crater were analyzed through series of synchrotron X-ray computed microtomographic experiments, as well as permeability measurements and simulations. Our goal was to reconstruct and visualize scoria textures in 3D and to quantify vesicularity, permeability, vesicle sizes and distributions in order to understand how gas moves in and out of Ambrym basaltic magma. We find that vesicle size distributions in the volume range between ~ 103 and 1010 μm3 define two scoria classes. Vesicle size distributions in the low-to-moderately (0.44–0.67) vesicular samples can be fit by power laws with an exponent of 1 ± 0.2; distributions in the highly vesicular (0.86–0.88) samples can be fit by power laws with a higher exponent (1.4 to 1.7), as well as by exponential fits. Highly vesicular samples exhibit a very pronounced large vesicle, consisting of networks of smaller, interconnected vesicles, that is more than three orders of magnitude larger in volume than all other vesicles in each distribution. This type of vesicle is not found in the low-to-moderately vesicular samples. In addition, vesicle number density negatively correlates with vesicularity: less vesicular samples have the highest number density and vice versa, and contain far more numerous small-to-medium-sized vesicles than highly vesicular samples. Measured and calculated viscous (Darcian) permeabilities overlap in the range 10− 13 and 10− 9 m2, with higher values in the more vesicular samples. We ascribe these differences in the textural and physical properties of the scoria clasts to their derivation from distinct magma portions in the conduit that were driven by convective overturn and underwent different vesiculation histories and gas transport dynamics. Comparing basaltic scoria clasts from Ambrym to those from mild explosive activity at Stromboli volcano (Italy) reveals that differences in their vesicle size distributions may result from the influence of different crystal contents and shapes on the vesiculation and permeability of the respective magmas. Finally, we highlight how rheological properties have a fundamental role in determining the degassing behaviour of basaltic magma at Ambrym and other volcanoes in general.en
dc.language.isoEnglishen
dc.publisher.nameElsevier Science Limiteden
dc.relation.ispartofJournal of volcanology and geothermal researchen
dc.relation.ispartofseries/233-234(2012)en
dc.subjectAmbrymen
dc.subjectBasaltic scoriaen
dc.subject3D X-ray micro-tomography analysisen
dc.subjectVolcanic degassingen
dc.subjectMagma convectionen
dc.subjectCrystal effecten
dc.titleDegassing behaviour of vesiculated basaltic magmas: an example from Ambrym volcano, Vanuatu Arcen
dc.typearticleen
dc.description.statusPublisheden
dc.type.QualityControlPeer-revieweden
dc.description.pagenumber55-64en
dc.subject.INGV04. Solid Earth::04.08. Volcanology::04.08.01. Gasesen
dc.subject.INGV04. Solid Earth::04.08. Volcanology::04.08.03. Magmasen
dc.subject.INGV04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocksen
dc.identifier.doi10.1016/j.jvolgeores.2012.04.019en
dc.description.obiettivoSpecifico2.3. TTC - Laboratori di chimica e fisica delle rocceen
dc.description.journalTypeJCR Journalen
dc.description.fulltextrestricteden
dc.relation.issn0377-0273en
dc.relation.eissn1872-6097en
dc.contributor.authorPolacci, M.en
dc.contributor.authorBaker, D. R.en
dc.contributor.authorLa Rue, A.en
dc.contributor.authorMancini, L.en
dc.contributor.authorAllard, P.en
dc.contributor.departmentIstituto Nazionale di Geofisica e Vulcanologia, Sezione Pisa, Pisa, Italiaen
dc.contributor.departmentEarth and Planetary Sciences, McGill University, Montreal, QC H3A2A7, Canadaen
dc.contributor.departmentSincrotrone Trieste S.C.p.A., 34149 Basovizza (Trieste), Italyen
dc.contributor.departmentInstitut de Physique du Globe, Paris Sorbonne Cité, CNRS UMR7154, Paris, Franceen
item.openairetypearticle-
item.cerifentitytypePublications-
item.languageiso639-1en-
item.grantfulltextrestricted-
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
item.fulltextWith Fulltext-
crisitem.author.deptIstituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione Pisa, Pisa, Italia-
crisitem.author.deptEarth and Planetary Sciences, McGill University, Montreal, QC H3A2A7, Canada-
crisitem.author.deptSincrotrone Trieste S.C.p.A., S.S. 14-km 163.5, 34149 Basovizza (TS), Italy-
crisitem.author.deptIstituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione OE, Catania, Italia-
crisitem.author.orcid0000-0003-3318-8700-
crisitem.author.orcid0000-0002-6543-3283-
crisitem.author.orcid0000-0001-7836-3117-
crisitem.author.parentorgIstituto Nazionale di Geofisica e Vulcanologia-
crisitem.author.parentorgIstituto Nazionale di Geofisica e Vulcanologia-
crisitem.classification.parent04. Solid Earth-
crisitem.classification.parent04. Solid Earth-
crisitem.classification.parent04. Solid Earth-
crisitem.department.parentorgIstituto Nazionale di Geofisica e Vulcanologia-
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