Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/462
Authors: | Piochi, M.* Mastrolorenzo, G.* Pappalardo, L.* |
Title: | Magma ascent and eruptive processes from textural and compositional features of Monte Nuovo pyroclastic products, Campi Flegrei, Italy | Journal: | Bulletin of volcanology | Series/Report no.: | 67 | Publisher: | Springer international | Issue Date: | 2005 | DOI: | 10.1007/s00445-005-0410-1 | URL: | www.springerlink.com | Keywords: | Campi Flegrei Monte Nuovo Microlite Crystal size distribution Magma degassing Syn-eruptive processes Volcanic hazard |
Subject Classification: | 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions |
Abstract: | Geochemical and textural studies were carried out on alkaline products of the AD 1538 Monte Nuovo eruption. Due to the integration of the volcanological study with eyewitness reports, the dynamics and timing of each phase of the eruption and the volume of emitted magmas are known in detail.On this basis, unique in Campi Flegrei, the relations between magma chamber mechanisms, eruptive styles, magma ascent dynamics and volatile exsolution processes have been explored. Glass and phenocryst compositions indicate that the erupted magma has a homogeneous phono-trachytic composition. Textures and compositions of phenocrysts indicate that they crystallised at equilibrium with the melt in the magma chamber, likely as a mushy boundary layer along the chamber wall, where the temperature was below the liquidus temperature of the crystal free-chamber core. The estimated crystallisation temperature is 850+-40°C. The magma phase relations in Petrogeny’s Residua System suggest that phenocryst crystallisation occurred at PH2O between 100 and 200 MPa, corresponding to depths ranging from 3 to 8 km. The microlite composition and their close genetic relations with vesicles indicate that groundmass crystallisation occurred during the eruption as a consequence of magma degassing and vesiculation induced by decompression during its ascent toward the surface. Crystal size distributions reveal that microlites grew in two stages of undercooling that we define as: (1) magma migration onset upward from the chamber and (2) magma rising through the conduit to the surface, possibly lasting tens of days and few days, respectively. These results provide information on the physical conditions that characterise pre- and syn-eruptive processes, which may be useful in order to define eruptive scenarios and to evaluate short-term precursors. Furthermore, the collected data provide for the first time information on degassinginduced crystallisation during the eruption of a highly evolved alkaline magma. |
Appears in Collections: | Article published / in press |
Files in This Item:
File | Description | Size | Format | Existing users please Login |
---|---|---|---|---|
Piochi.pdf | 718.11 kB | Adobe PDF | ||
springerlink.htm | redirect - springerlink | 447 B | HTML | View/Open |
WEB OF SCIENCETM
Citations
50
56
checked on Feb 10, 2021
Page view(s) 20
345
checked on Apr 27, 2024
Download(s)
98
checked on Apr 27, 2024