Publication Date:
2017-04-04
Description:
Abstract The Campi Flegrei (Campanian Region, Italy)
experienced two cataclysmic caldera-forming eruptions
which produced the Campanian Ignimbrite (39 ka, CI)
and the Neapolitan Yellow Tuff (15 ka, NYT). We studied
the minor eruptions before both these large events to
understand magma chamber evolution leading towards such
catastrophic eruptions. Major, trace element, and Sr and Nd
isotope compositions of pre-Campanian Ignimbrite and pre-
Neapolitan Yellow Tuff products define distinct geochem-
ical groups, which are here interpreted as distinct magma
batches. These batches do not show any transitional trend
towards the CI and NYT eruptions. The CI and NYT
systems are decoupled geochemically and isotopically. At
least one of the pre-CI and one of the pre-NYT erupted
magma batches qualifies as mixing endmembers for the
large CI and NYT eruptions, and thus, must have been
stored in reservoirs for some time to remain available for
the CI and NYT eruptions. The least evolved, isotopically
distinct magma compositions that are typical of the last
phases of the NYT and CI eruptions did not occur before
caldera-forming events. Based on the new data, we propose
the following scenario: Multiple magma chambers with
distinct compositions existed below the Campi Flegrei
before the CI and NYT eruptions and remained generally
separated for some time unless new magma was recharged.
In each case, one of the residing magma reservoirs was
recharged by a new large-volume magma input of interme-
diate composition from a deeper differentiating magma
reservoir. This may have triggered the coalescence of the
previously separated reservoirs into one large chamber
which fed the cataclysmic caldera-forming eruption. Large
magma chambers in the Campi Flegrei may therefore be
ephemeral features, interrupted by periods of evolution in
individual, separated magma reservoirs.
Description:
Published
Description:
on line first
Description:
2.3. TTC - Laboratori di chimica e fisica delle rocce
Description:
3.5. Geologia e storia dei sistemi vulcanici
Description:
JCR Journal
Description:
reserved
Keywords:
Campi Flegrei
;
Phlegraean fields
;
Campanian Ignimbrite
;
Neapolitan Yellow Tuff
;
04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology
;
04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
;
05. General::05.06. Methods::05.06.99. General or miscellaneous
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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