Rocas piroclásticas asociadas conla formación de la caldera de Guayabo, Cordillera de Guanacaste, Costa Rica

The volcanic depression of the Guayabo calderas was emplaced during several collapses between 1.5 to 0.6 m.y. ago. These eruptions are recorded in a series of pumice-ash flows, pyroclastic surges and air-falls tuffs, called Guayabo Formation, that are exposed in the western and southern part of the...

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Autores Principales: Chiesa, Sergio, Civelli, Giovanna, Gillot, Pierre Yves, Mora, Oscar, Alvarado Induni, Guillermo E.
Formato: Artículo
Idioma: Español
Publicado: Universidad de Costa Rica 2011
Acceso en línea: http://revistas.ucr.ac.cr/index.php/geologica/article/view/13218
http://hdl.handle.net/10669/22686
Sumario: The volcanic depression of the Guayabo calderas was emplaced during several collapses between 1.5 to 0.6 m.y. ago. These eruptions are recorded in a series of pumice-ash flows, pyroclastic surges and air-falls tuffs, called Guayabo Formation, that are exposed in the western and southern part of the Guayabo caldera rim. The pyroclastic-flow sheets represent more than 30 km3 of dacitic to rhyolitic magma associated to crystal fractionation processes. The volumen and also the energy of the  eruptions decrease in the time. Microprobe and geobarometric analyses of amphiobole suggest that the level of the magma chamber was less than 5 km.