Caracterización Geoquímica e isotópica del complejo Volcánico La Hoyada, Puna Austral

BUSTOS, EMILCE; MATTEINI MASSIMO; ARNOSIO, MARCELO

Congreso; XIII CONGRESO DE MINERALOGÍA, PETROLOGÍA ÍGNEA Y METAMÓRFICA, Y METALOGÉNESIS; 2019

Geochemical and Isotopic Characterization of La Hoyada Volcanic Complex, Southern Puna. Central Volcanic Zone (CVZ) is characterized by high values of 87 Sr/ 86 Sr t (0,705 ?0,708) and low ƐNd (-2 a -8) in response to the continental crust incorporated in this region. La Hoyada Volcanic Complex (LHVC), located at Southern Puna, corresponds to a set of andesitic-dacitic volcanic centers of upper-Pleistocene Miocene age. LHVC rocks are classified as basaltic andesitic to rhyolite, with the highest proportion in intermediate composition fields. During the evolution of the CVLH, at least 6 volcanic edifices were built in a restricted area during ~ 6 Ma. The geochemical behavior of the LHVC supports the increase in cortical contamination from 8 to 5 Ma proposed for the area coinciding with the main phase of cortical thickening in the CVZ. Geochemistry of mafic lavas of the LHVC, coincide with the geochemical characteristics observed in the monogenetic volcanism for the Southern Puna. LHVC units with similar composition and different ages have geotermobarometric conditions dissimilar. The analysis of the geochemical data shows the complexity of the LHVC magmatic system, which was constituted by different reservoirs, each of them represents different episodes of magmatic evolution. The analysis of the evolution of complex and long-term magmatic systems with geochemical data must be approached taking into account the stratigraphic position of the units that make up the volcanic edifices.