IGEBA   23946
INSTITUTO DE GEOCIENCIAS BASICAS, APLICADAS Y AMBIENTALES DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
La Peligrosa caldera (47º 15´S, 71° 40´W): a key event during the Jurassic ignimbrite flare-up in Southern Patagonia, Argentina
Autor/es:
SRUOGA, PATRICIA; JAPAS, MARÍA SILVIA; SALANI, FLAVIA; KLEIMAN, LAURA E.
Revista:
JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2014 vol. 269 p. 44 - 56
ISSN:
0377-0273
Resumen:
Abstract Pyroclastic and lava vent-facies, from the Late Jurassic El Quemado Complex, are described at the southern Lake Ghío, in the Cordillera Patagónica Austral. Based on the comprehensive study of lithology and structures, the reconstruction of the volcanic architecture has been carried out. Four ignimbritic and one rhyolitic lava units, affected by transtensional faults have been recognized. The evolution of La Peligrosa Caldera has been modeled in three different stages:1) initial collapse, consisting in a precursory downsag subsidence, related to a dilatational zone, which controlled both location and geometry of the caldera 2) main collapse, with the emplacement of large volume crystal-rich ignimbrites and megabreccias, under a progressive subsidence controlled by a transtensional regime, and 3) post-collapse, in which lava flows and associated domes were emplaced under an oblique extensional regime. The caldera records a remarkable change from transtension to oblique extension, which may represent an important variation in regional deformation conditions during Jurassic times. La Peligrosa Caldera may be considered a key event to understand the eruptive mechanisms of the flare-up volcanism in the Silicic Chon Aike Province.