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Volatile Evolution of Magma Associated with the Solchiaro Eruption in the Phlegrean Volcanic District (Italy)
Citation
Esposito, R and Bodnar, RJ and Danyushevsky, LV and De Vivo, B and Fedele, L and Hunter, J and Lima, A and Shimizu, N, Volatile Evolution of Magma Associated with the Solchiaro Eruption in the Phlegrean Volcanic District (Italy), Journal of Petrology, 52, (12) pp. 2431-2460. ISSN 0022-3530 (2011) [Refereed Article]
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Copyright Statement
Copyright 2011 Oxford University Press.
DOI: doi:10.1093/petrology/egr051
Abstract
More than 1.5 million people live in or near the Phlegrean Volcanic
District (PVD) in southern Italy, which represents one of the most
carefully studied volcanic hazard areas in the world.Throughout its
history, the style of volcanic activity has varied greatly, from relatively
quiescent lava flows to explosive phreatomagmatic eruptions.
The goal of this study is to develop a more detailed understanding
of the physical and chemical processes associated with the Solchiaro
eruption in the PVD. The PVD includes three volcanic fields: the
Campi Flegrei (CF) caldera and the volcanic islands of Ischia and
Procida. The Solchiaro eruption on the island of Procida is one of
the few primitive (less evolved) eruptions in the PVD and can
provide information on the source of the more evolved magmas associated
with this volcanic system. One of the more important chemical
parameters that determine the style of volcanic eruptions is the volatile
budget of the magma before and during eruption.Melt inclusions
(MI) provide the most direct information on the volatile contents
of the pre-eruptive melt in the source region for the PVD.The composition
of the melt phase before eruption was determined by analyzing
the major, minor and trace element and volatile contents of 109 MI
in olivine from four samples of the Solchiaro eruption, representing
different stratigraphic heights in the deposits and, therefore, different
relative times of eruption. Olivine compositions vary from Fo82 to
Fo88, with one maximum value of Fo90.The compositions of the MI
in olivine were corrected for post-entrapment crystallization (PEC)
and for Fe loss by diffusion. Most (97 out of 109) of the MI studied
are classified as 'normal'MI because they show chemical evolution
trends consistent with that of bulk-rocks from the PVD.Two types
of anomalous MI were also recognized based on their major and
trace element compositions: (1) Sr-rich MI, and (2) enriched MI
that are variably enriched inTiO2, K2O, P2O5, large ion lithophile
elements, high field strength elements and rare earth elements relative
to 'normal'MI. These MI probably originated from dissolution-
reaction-mixing processes in the mush zone of the magma body.
'Normal'MI include both bubble-bearing and bubble-free (containing
only glass+-trapped chromite) types. Bubble-free MI most
closely record the pre-eruptive volatile content of the melt over a
range of temporal and spatial conditions. The observed trends in
CO2 contents of MI versus crystallization indicators (e.g. Al2O3/
CaO) support the interpretation that variations in the volatile
contents of bubble-free MI reflect real variations in the volatile
budget of the melt during the evolution of the magma.The correlation
between CO2 contents of MI and the relative stratigraphic position
of each sample is consistent with eruption of a volatile-saturated
magma that initially ascended through the crust from an original
depth of at least 8 km.The magma ponded at 4^2 km depth prior to
eruption and crystallization and the concomitant volatile exsolution from the saturated melt in the shallow chamber triggered the
Solchiaro eruption. As the eruption proceeded, the Solchiaro magma
continued to ascend through the crust to a final storage depth of
about 1km.
Item Details
Item Type: | Refereed Article |
---|---|
Keywords: | melt inclusions volatiles magma degassing Italy |
Research Division: | Earth Sciences |
Research Group: | Geology |
Research Field: | Igneous and metamorphic petrology |
Objective Division: | Expanding Knowledge |
Objective Group: | Expanding knowledge |
Objective Field: | Expanding knowledge in the earth sciences |
UTAS Author: | Danyushevsky, LV (Professor Leonid Danyushevsky) |
ID Code: | 74846 |
Year Published: | 2011 |
Web of Science® Times Cited: | 59 |
Deposited By: | Centre for Ore Deposit Research - CODES CoE |
Deposited On: | 2011-12-14 |
Last Modified: | 2022-08-25 |
Downloads: | 0 |
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