INVESTIGADORES
PETRINOVIC Ivan Alejandro
artículos
Título:
La Caldera de colapso del Cerro Aguas Calientes, Salta; República Argentina; Evolución y Esquema Estructural
Autor/es:
PETRINOVIC, I.A.
Revista:
ACTA GEOLOGICA HISPANICA
Referencias:
Año: 1999 vol. 34 p. 243 - 255
ISSN:
0567-7505
Resumen:
A new emission centre
of extensive pyroclastic flows has been recognised and interpreted, near San Antonio de los
Cobres. The eruptive parameters and the volcanic history of the volcanic
complex are pointed out.
A caldera collapse
controlled by left-lateral strike-slip faulting is proposed. The age of this
caldera is 10-10.5 Ma. The least vesiculated magma volume is 200-250 km3.
The identified
pyroclastic flows are Verde Ignimbrite, Chorrillos Ignimbrite, Tajamar
Ignimbrite and Abra del Gallo Ignimbrite. The volcanic history started with
explosive events and opening of vents. The initial collapse of the caldera was
asymmetric and only the eastern side developed. The eruption of the Verde
Ignimbrite took place in this stage in a central vent. The continuous collapse
and the opening of rim vents are related with the Chorrillos, Tajamar and Abra del Gallo
ignimbrites. The Ignimbrite Tajamar is the principal collapse with intracaldera
characteristics. The extracaldera facies is represented by the Ignimbrite Abra
del Gallo. The collapse is completed in a short period of time, followed by a
generalised resurgence in the caldera floor. Regional detumescence and probably
the intrusion of a dome produced this resurgence. The postcaldera activity is
represented by hydrotermal-geothermal activity. All of this process took place
in a short period of time, ca 10-10.5 Ma.
The field and
petrographic data are coherent with the direction determinations of the Magnetic
Anisotropy Susceptibility, and with the calculated temperatures of emplacement.
The magmatic chamber
geometry and the collapse of a caldera were controlled by the regional
structural scheme. A WNW-ESE trend strike-slip fault system with left lateral
movement called Calama-Olacapato-El Toro Lineament, caused the local
distension. These strike-slip faults continued and deformed the north side of
the caldera.
The magmatic system
could have migrated to the west originating the Quevar volcanic complex (8Ma).