Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/8918
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dc.contributor.authorallLanzafame, G.; Università Cataniaen
dc.contributor.authorallMollo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italiaen
dc.contributor.authorallIezzi, G.; Università Chietien
dc.contributor.authorallFerlito, C.; Università Cataniaen
dc.contributor.authorallVentura, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italiaen
dc.date.accessioned2014-02-10T11:16:19Zen
dc.date.available2014-02-10T11:16:19Zen
dc.date.issued2013en
dc.identifier.urihttp://hdl.handle.net/2122/8918en
dc.description.abstractThe solidified surface of a lava flow reflects the viscosity of its molten fraction and the crystal content during flow; crystal-poor basaltic lavas produce pahoehoe fields, whereas crystal-rich ones solidify with aa carapaces. At Mount Etna, volcano aa morphologies are very common, whereas pahoehoe lavas are rare. The latter are locally named “cicirara” due to the presence of centimeter-sized plagioclase phenocrysts much more abundant than in aa lavas. The phenocryst content of “cicirara” lavas contrasts with the low viscosity generally associated with pahoehoe morphology. Therefore, to reconcile the discrepancy between textural and volcanic observations, we have studied the most primitive pahoehoe “cicirara” lava sampled until now. Two samples at 0.5 and 1 m from the bottom of the 2- m thick lava flow were investigated on the basis of their mineral compositional variations and textural features, i.e., size frequency and crystal size distribution (CSD). Results coupled with rheological models indicate that only large phenocrysts of plagioclase (>1 mm) and clinopyroxene have grown before eruption. Thermobarometric models and petrological computations based on the composition of plagioclase and clinopyroxene phenocryst cores highlight that only a small amount (10–15 vol.%) of crystals equilibrated at 12 km of depth. Cumulative size frequency and CSD data also indicate that plagioclase and clinopyroxene phenocryst rims grew heterogeneously and coalesced around their cores at depths <1 km, before eruption. In this view, the “cicirara” lava was erupted with a low crystalline content that favoured the formation of its pahoehoe surface; however, crystals with a size <1 mm (~75 vol.%) solidified at post-eruptive conditions. Our findings underline that the emplacement of high-viscosity aa or low-viscosity pahoehoe lavas is driven by the degree of undercooling imposed by the volatile exsolution rate in the shallowest portion of the Etnean plumbing system. A slow magma ascent rate promotes significant intratelluric degassing and widespread nucleation; consequently, the viscosity of the suspension significantly increases leading to an aa morphology. In contrast, pahoehoe “cicirara” lavas are associated with a rapid rise to the surface of poorly degassed, undercooled magmas.en
dc.language.isoEnglishen
dc.publisher.nameSpringer Berlin Heidelbergen
dc.relation.ispartofBulletin of volcanologyen
dc.relation.ispartofseries/75(2013)en
dc.subjectcicirara lava flowen
dc.titleUnraveling the solidification path of a pahoehoe "cicirara" lava from Mount Etna volcanoen
dc.typearticleen
dc.description.statusPublisheden
dc.type.QualityControlPeer-revieweden
dc.description.pagenumber703en
dc.subject.INGV04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocksen
dc.identifier.doi10.1007/s00445-013-0703-8en
dc.description.obiettivoSpecifico2R. Laboratori sperimentali e analiticien
dc.description.journalTypeJCR Journalen
dc.description.fulltextrestricteden
dc.relation.issn0258-8900en
dc.relation.eissn1432-0819en
dc.contributor.authorLanzafame, G.en
dc.contributor.authorMollo, S.en
dc.contributor.authorIezzi, G.en
dc.contributor.authorFerlito, C.en
dc.contributor.authorVentura, G.en
dc.contributor.departmentUniversità Cataniaen
dc.contributor.departmentIstituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italiaen
dc.contributor.departmentUniversità Chietien
dc.contributor.departmentUniversità Cataniaen
dc.contributor.departmentIstituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italiaen
item.openairetypearticle-
item.cerifentitytypePublications-
item.languageiso639-1en-
item.grantfulltextrestricted-
item.openairecristypehttp://purl.org/coar/resource_type/c_18cf-
item.fulltextWith Fulltext-
crisitem.author.deptUniversità di Roma "La Sapienza"-
crisitem.author.deptUniversità degli studi G. D'annunzio, Chieti Pescara, Italy-
crisitem.author.deptDip. Scienze Geologiche, Università di Catania-
crisitem.author.deptIstituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione Roma1, Roma, Italia-
crisitem.author.orcid0000-0001-9388-9985-
crisitem.author.parentorgIstituto Nazionale di Geofisica e Vulcanologia-
crisitem.classification.parent04. Solid Earth-
crisitem.department.parentorgIstituto Nazionale di Geofisica e Vulcanologia-
crisitem.department.parentorgIstituto Nazionale di Geofisica e Vulcanologia-
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