Please use this identifier to cite or link to this item:
http://hdl.handle.net/2122/14483
Authors: | Giuffrida, Marisa* Nicotra, Eugenio* Viccaro, Marco* |
Title: | Changing modes and rates of mafic magma supply at Pantelleria (Sicily Channel, Southern Italy): new perspectives on the volcano factory drawn upon olivine records | Journal: | Journal of petrology | Series/Report no.: | 5/61 (2020) | Publisher: | Oxford University Press | Issue Date: | 2020 | DOI: | 10.1093/petrology/egaa051 | Abstract: | The island of Pantelleria, located in the Sicily Channel Rift Zone (Italy), has been the site of violent peralkaline silicic magmatism alternating with minor effusive to low-intensity Strombolian erup- tions of basaltic composition. The basaltic rock suites exposed on the island were sampled to in- vestigate the plumbing system dynamics through the study of chemical stratigraphy and temporal records of olivine crystals. Our petrographic and geochemical observations, together with the com- positional variability of olivine, suggest different evolutionary histories for basaltic magmas erupted over two major periods divided by the 45 ka Green Tuff (GT) eruption. Core-to-rim com- positional traverses across olivine crystals document different types of zoning. We recognized oliv- ine zones affected by Fo oscillations at very fine scales in the inner cores, rims and/or in intermedi- ate portions of crystals and used them to reconstruct the residence and passage of crystals through different magmatic environments, with P–T–ƒO2 and compositional characteristics con- strained by thermodynamic modeling. The sequence of magmatic environments evidenced by oliv- ine zoning indicate that the pre-GT volcanic period was dominated by injection at shallow crustal levels (300–200 MPa) of primitive melts, initially moving from a deep storage zone at the crust- mantle boundary. Supply of this magma significantly decreased after the GT eruption, while the dy- namics of magma transfer within the upper portion of the plumbing system were greatly enhanced. The diffusive relaxation of olivine zoning provided the timing of storage and migration of a crystal through different environments. For magmas feeding the ancient (>45 ka) basaltic activ- ity we retrieved transfer histories that are much longer (up to 3 years) if compared with those cal- culated for the post-GT basalts (1–9 months). The compositional and temporal dataset presented in this study supports the idea that the GT eruption and the subsequent collapse of the volcanic edi- fice could have caused major changes to the internal structural setting of Pantelleria, creating more favorable conditions for the migration of magmas in the upper portions of the plumbing system. |
Appears in Collections: | Article published / in press |
Files in This Item:
File | Description | Size | Format | Existing users please Login |
---|---|---|---|---|
Changing Modes and Rates of Mafic Magma Supply at Pantelleria.pdf | 2.83 MB | Adobe PDF |
Page view(s)
41
checked on Apr 24, 2024
Download(s)
3
checked on Apr 24, 2024