PETROGÉNESIS DEL COMPLEJO VOLCÁNICO HUAYRA HUASI, PUNA NORTE, ARGENTINA

JOFRE, C.B.; CAFFE, P.J.; MARO, G. .; TRUMBULL, R.B.; SCHMITT, A.K.

Congreso; XIII Congreso de Mineralogía Petrología Ignea Y Metamórfica Y Metalogénesis XIII MINMET- IV PIMMA; 2019

The Huayra Huasi Volcanic Complex comprises a series of intrusive-volcanic bodies of Miocene age, located on the east margin of Olaroz Salar. It is conformed of biotite-bearing dacites and riodacites and SiO2-rich rhyolites. These rocks present a high peraluminosity (A/CNK>1,1), that allows to relate them to S-type magmatism. The units are comprised by plagioclase, quartz and sanidine, with presence of mafic inclusions and metamorphic xenoliths and aluminosilicate aggregates (rich in sillimanite). The studies indicate this Complex evolves from a dacitic magma through assimilation and fractional crystallization processes in a stratified magmatic chamber, until reaching peraluminous rhyolitic compositions. The presence of mineral aggregates conformed almost totally by refractory minerals is interpreted as the solid product of melting (peritectic or restitic phases) of metasedimentary contaminants. The petrologic characteristics of the Complex highlight the primordial role of the assimilation of upper cortical material in the evolution of the Huayra Huasi magmatism.