CARACTERIZACIÓN PETROGRÁFICA Y GEOQUÍMICA DEL VOLCÁN CUEROS DE PURULLA, PUNA AUSTRAL

BERTEA, ESTEBAN SANTIAGO; BARDELLI, LORENZO; ARNOSIO, MARCELO; SOMMER, CARLOS A.; BÁEZ, WALTER

Córdoba

Congreso; XIII Congreso de Mineralogía, Petrología Ígnea y Metamórfica, y Metalogénesis (XIII MINMET y IV PIMMA); 2019

Asociación Geológica Argentina, Asociación Mineralógica Argentina, COMPETRO

The Southern Puna is characterized by the presence of Miocene to Holocene silicic volcanism. One of the representatives of this activity is the Cueros de Purulla Volcano (CDPV), located 20 km NW of the Cerro Blanco Volcanic Complex (CBVC) on the eastern flank of the Sierra de Calalaste. The CDPV was poorly studied in the past, reason why we here present a petrographic and geochemical characterization of the volcano and a comparison with other rhyolitic volcanic deposits of the Andean back-arc area. The CDPV products are slightly peraluminous crystal-poor rhyolitic rocks (lava domes, fall deposits) with cryptocrystalline-vitreous matrix which belong to the high-K calc-alkaline series. These deposits display geochemical affinities with most of the Miocene to Pleistocene rhyolites outcropping in the Southern Puna (e.g. high Rb and Ba contents) and some differences with the Cerro Blanco deposits and other rhyolitic centers from the northern Puna. We infer that the CDPV rhyolites may represent the periodical extraction of differentiated melts from a fairly homogeneous crystal-mush zone beneath the Southern Puna. This hypothesis is also supported by geophysical evidence (teleseismic tomography).