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Fractures and faults in volcanic rocks (Campi Flegrei, southern Italy): Insight into volcano-tectonic processes
Language
English
Obiettivo Specifico
2V. Struttura e sistema di alimentazione dei vulcani
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/103 (2014)
Pages (printed)
801–819
Issued date
2014
Abstract
The present study was focused to analyze fractures
and faults in the Campi Flegrei calderas presently
hosting several volcanic edifices, such as lava domes, scoria,
and tuff cones. A complex network of fractures and
faults affects the volcanic rocks, mostly as planar with
highly variable density. Frequently faults appearing as conjugate
structures showing normal kinematics often associated
with ductile deformation such as drag folds and
deflexed layers, suggesting a syn-eruption deformation.
However, the most of faults, mainly hosted along the caldera/
crater rims, are very steep with dominant normal and
secondary reverse movements. The fracture pattern indicates
a slight prevalence of NE–SW and NW–SE directions,
but N–S and E–W trends also occur. Fractures and
faults found in rocks older than 15 ka (Neapolitan Yellow
Tuff included), measured in western and eastern sectors of
the study area, indicate a rotation of ca. 30° of the main
directions among these two sectors. For the faults occurring
along the caldera/crater rims, we suggest a kinematic evolution
characterized by the reactivation of tensile fractures
previously formed in response to both regional extension
and locale resurgent dome. Finally, normal faults located in the central sector of caldera, between La Starza and Accademia
localities, cutting the youngest volcanic deposits,
indicate a constant NNE–SSW extension probably related
to the caldera resurgence.
and faults in the Campi Flegrei calderas presently
hosting several volcanic edifices, such as lava domes, scoria,
and tuff cones. A complex network of fractures and
faults affects the volcanic rocks, mostly as planar with
highly variable density. Frequently faults appearing as conjugate
structures showing normal kinematics often associated
with ductile deformation such as drag folds and
deflexed layers, suggesting a syn-eruption deformation.
However, the most of faults, mainly hosted along the caldera/
crater rims, are very steep with dominant normal and
secondary reverse movements. The fracture pattern indicates
a slight prevalence of NE–SW and NW–SE directions,
but N–S and E–W trends also occur. Fractures and
faults found in rocks older than 15 ka (Neapolitan Yellow
Tuff included), measured in western and eastern sectors of
the study area, indicate a rotation of ca. 30° of the main
directions among these two sectors. For the faults occurring
along the caldera/crater rims, we suggest a kinematic evolution
characterized by the reactivation of tensile fractures
previously formed in response to both regional extension
and locale resurgent dome. Finally, normal faults located in the central sector of caldera, between La Starza and Accademia
localities, cutting the youngest volcanic deposits,
indicate a constant NNE–SSW extension probably related
to the caldera resurgence.
Type
article
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Vitale & Isaia, 2014.pdf
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