Abstract

MARQUEZ, Marcelo J; MASSAFERRO, Gabriela I  and  FERNANDEZ, María I. The volcanism of the Marifil Complex in Arroyo Verde, Southeastern slope of the Somun Cura Massif, Chubut. Rev. Asoc. Geol. Argent. [online]. 2010, vol.66, n.3, pp.314-324. ISSN 0004-4822.

Marifil Complex volcanic facies that crop out in the locality of Arroyo Verde, SE slope of Macizo de Somún Cura, are described here. Rhyolitic ignimbrite facies, pyroclastic breccias, traquitic domes and vitreous domes, and rhyolitic dikes are distinguished. Field relationships point out the ignimbrites as the first effusive event. Some sporadically block and ash flows are intercalated within the ignimbrites. These deposits were intruded by domes; the latest event is represented by the intrusion of the rhyolitic dykes. Chemical composition of these rocks varies between high K rhyolites and traquites, which correspond to typical characteristics of the Marifil Complex rocks. The observations allow proposing a fissural mechanism of eruption for these facies in this locality.

Keywords : Somún Cura; Liasic volcanism; Volcanic lithofacies; Fissural eruptions.

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