Geochemical Evidences that Unrest at Campi Flegrei Resurgent Caldera (Southern Italy) Is Due to Magma Emplacement and Degassing at Shallow Depth Plus Fluxing from a Deep-Seated Regional Body

Puerto de la Cruz,Tenerife (Canary Islands,Spain)

Volcanic calderas are affected by unrest episodes usually
dominated by hybrid magmatic-hydrothermal system
dynamics. Unrest episodes can evolve to eruptions
of variable intensity, up to Plinian. Campi Flegrei caldera
(CFc) is a type-location for this kind of activity escalation.
CFc offers unique opportunity to join volcanological
information to a long record of geochemical parameters.
This allows understanding the role that magmatic
system plays on variations displayed by the hydrothermal
system. We model uneruptive unrest episodes as
driven by i) the shallow emplacement (~4 km depth) of
one volatile-rich magma batch ascending from a deep
(≥ 8 km) magmatic body of regional extent, ii) subsequent
gas separation with degassing driven by crystallization
and iii) fluxing from the deep magmatic body.
Our model matches three decades of geochemical constraints
from fumarole discharges, as well as data from melt inclusions of past CFc eruptions. Besides, magma
physical properties demanded for modeled degassing
conditions are in good agreement with existing geophysical
data. Our results open new perspectives to the
definition of unrest scenarios at highly-populated CFc,
as well as other resurgent calderas (e.g., Orsi et al., This
Assembly).