 |
| Titel |
the sub-Plinian Greenish Pumice eruption (19,065±105 yr cal BP) of Mount Somma – Vesuvius. Geochemical and textural constrains. |
| VerfasserIn |
Géraldine Zdanowicz, Georges Boudon, Hélène Balcone-Boissard, Raffaello Cioni, Filippo Mundula, Giovanni Orsi, Lucia Civetta |
| Konferenz |
EGU General Assembly 2016
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127109
|
| Publikation (Nr.) |
 EGU/EGU2016-6940.pdf |
|
|
|
|
|
| Zusammenfassung |
| Researches are currently focused on large intensity and stable eruptive columns as for Plinian event. But the large variability in deposits issued from sub-Plinian eruptions needs more observations, theoretical and experimental investigations to be better described and enhances criteria of classification and the knowledge on processes at the origin of this unsteadiness of various timescales.
Here, we focus on the well-known example of sub-Plinian eruption exhibiting by Mount Somma-Vesuvius: the Greenish Pumice eruption (GP). On the basis of coupled geochemical and textural analyses we investigate the volatile behavior (H2O, CO2 and halogen (F, Cl)) to better constrain (1) the magma reservoir location and pre-eruptive state and (2) the sub-Plinian eruptive style through a detailed study of the degassing processes in relation with the dynamic of the eruptive column.
Results evidence that Cl act as a geobarometer for the trachytic-phonolitic melt involved during the eruption indicating that magma reservoir was at 100 MPa (Cl buffer value: 5300 ±130 ppm) and wholly H2O-saturated (pre-eruptive H2O content between 3.8 and 5.2 wt%). The eruption dynamic is clearly explained by open-system degassing processes responsible of the eruptive column instability, correlated to textural heterogeneities of the eruptive products reflecting conduit heterogeneity (smaller diameter and higher horizontal gradient in magma ascent velocity). |
|
|
|
|
|
|