Publication Date:
2017-04-04
Description:
More than ca 100 km3 of nearly homogeneous
crystal-poor phonolite and ca 100 km3 of slightly zoned
trachyte were erupted 39 ka during the Campanian
Ignimbrite super eruption, the most powerful in the Neapolitan
area. Partition coefficient calculations, equilibrium
mineral assemblages, glass compositions and texture were
used to reconstruct compositional, thermal and pressure
gradients in the pre-eruptive reservoir as well as timing and
mechanisms of evolution towards magma chamber overpressure
and eruption. Our petrologic data indicate that a
wide sill-like trachytic magma chamber was active under
the Campanian Plain at 2.5 kbar before CI eruption.
Thermal exchange between high liquidus (1199 C)
trachytic sill and cool country rocks caused intense
undercooling, driving a catastrophic and fast (102 years) in
situ fractional crystallization and crustal assimilation that
produced a water oversaturated phonolitic cap and an
overpressure in the chamber that triggered the super
eruption. This process culminated in an abrupt reservoir
opening and in a fast single-step high decompression.
Sanidine phenocrysts crystal size distributions reveal high differentiation rate, thus suggesting that such a sill-like
magmatic system is capable of evolving in a very short
time and erupting suddenly with only short-term warning.
Description:
Published
Description:
On line First
Description:
2.3. TTC - Laboratori di chimica e fisica delle rocce
Description:
3.6. Fisica del vulcanismo
Description:
4.3. TTC - Scenari di pericolosità vulcanica
Description:
JCR Journal
Description:
reserved
Keywords:
Campanian Ignimbrite
;
Super eruption
;
Crystal size distribution
;
Partition coefficients
;
04. Solid Earth::04.04. Geology::04.04.04. Marine geology
;
04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology
;
04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
