The geological and structural evolution of the long-lived Miocene-Pleistocene La Hoyada Volcanic Complex in the geodynamic framework of the Central Andes, Argentina

BÁEZ, W.; DE SILVA, S.L.; BUSTOS, E.; ARNOSIO, M.; NORINI, G.

JOURNAL OF VOLCANOLOGY AND GEOTHERMAL RESEARCH

ELSEVIER SCIENCE BV

Año: 2018

0377-0273

The long-lived La Hoyada Volcanic Complex (LHVC) is located in the east of Cordillera de San Buenaventura in Argentina. This region is important for understanding of the geodynamic evolution of the Southern Puna, since it is located in its southern edge, where the transition between normal and low-angle subduction occurs. The aim of this work is to contribute to the knowledge of the volcanism of the Southern Puna through the analysis of the stratigraphy and geological evolution of LHVC. Fieldwork and image analysis have led to a new lithostratigraphic scheme, that identifies lithosomes and unconformity-bounded stratigraphic units defining the stratigraphic architecture of the LHVC. New 40Ar/39Ar ages further constrain the geological evolution of this complex. The resulting stratigraphic scheme combines the lithostratigraphic units into lithosomes and synthemic units, with the identification of at least six superimposed eruptive centers and their products during the LHVC evolution. A new stratigraphic framework for the eastern Cordillera de San Buenaventura, composed by four supersynthems separated by unconformities that reflect periods of quiescence of the volcanic activity, catastrophic destructive events and changes in the magmatic plumbing system, is proposed: 1) San Buenaventura supersynthem (ca. 9?7 Ma), including mainly explosive rhyolitic volcanism; 2) Lower La Hoyada supersynthem (ca. 7?