Evolution of Irruputuncu volcano, Central Andes, northern Chile. (November 2015)

• Record Type: Journal Article
• Authors: Rodríguez, I.; Roche, O.; Moune, S.; Aguilera, F.; Campos, E.; Pizarro, M.
• Is Part Of: Journal of South American earth sciences. Volume 63(2015:Nov.)
• Page Start: 385
• Page End: 399
• Publication Date: 2015-11
• Subjects: Irruputuncu volcano -- Central Andes -- Debris avalanche -- Block and ash flow -- Lava flow; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2015.08.012
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: The Irruputuncu is an active volcano located in northern Chile within the Central Andean Volcanic Zone (CAVZ) and that has produced andesitic to trachy-andesitic magmas over the last ∼258 ± 49 ka. We report petrographical and geochemical data, new geochronological ages and for the first time a detailed geological map representing the eruptive products generated by the Irruputuncu volcano. The detailed study on the volcanic products allows us to establish a temporal evolution of the edifice. We propose that the Irruputuncu volcanic history can be divided in two stages, both dominated by effusive activity: Irruputuncu I and II. The oldest identified products that mark the beginning of Irruputuncu I are small-volume pyroclastic flow deposits generated during an explosive phase that may have been triggered by magma injection as suggested by mingling features in the clasts. This event was followed by generation of large lava flows and the edifice grew until destabilization of its SW flank through the generation of a debris avalanche, which ended Irruputuncu I. New effusive activity generated lavas flows to the NW at the beginning of Irruputuncu II. In the meantime, lava domes that grew in the summit were destabilized, as shown by two well-preserved block-and-ash flow deposits. The first phase of dome collapse, in particular, generated highly mobile pyroclastic flows that propagated up to ∼8 km from their source on gentle slopes as low as 11° in distal areas. The actual activity is characterized by deposition of sulfur and permanent gas emissions, producing a gas plume that reaches 200 m above the crater. The maximum volume of this volcanic system is of ∼4 km 3, being one of the smallest active volcano of Central Andes. Highlights: We provide the first detailed geological map of Irruputuncu volcano. Magmas from the Irruputuncu volcano have similar composition with other volcanoes of the Central Andes. Minerals assemblage presents disequilibrium textures, which suggests magma mixing. We provide with new Ar/Ar ages to better constrain the temporal evolution of the Irruputuincu volcano.