MIOCENE-PLIOCENE HIGH-Sr INTERMEDIATE AND ACID ROCKS IN THE SIERRA DEL NEVADO, PAYENIA

RUBIANO LORENZONI, GEORGINA; ORIHASHI YUJI; BERTOTTO GUSTAVO WALTER; JALOWITZKI TIAGO; SUMINO HIROCHIKA; PONCE, ALEXIS D.; BERNARDI, MAURO I.; HIRATA, DAIJI

Puerto Madryn

Congreso; XXI Congreso Geológico Argentino; 2022

Asociación Geológica Argentina

Late Cenozoic magmatism located in the northeastern area of the Andean Southern Volcanic Zone(34°-38°S) is characterized by voluminous eruptions of intermediate to felsic rocks and by monogenetic mafic volcanism. Sierra del Nevado (35º25?-35º45ºS and 68º10?-68º47?W) represents an example of silicic back-arc volcanism situated more than 200 km from the Andean volcanic arc (e.g., Holmberg 1973, Sepúlveda et al. 2007). Three main Miocene-Pleistocene volcanic units have been described in this area: a) felsic to intermediate rocks of Cortaderas Formation, b) intermediate to mafic rocks of Nevado Formation, and c) basaltic rocks of Chapúa Group.In this work, new petrographic and geochemical data coupled with K-Ar ages of rocks from Cortaderas Formation are presented. These complement previous field observations, petrographic descriptions, whole-rock geochemistry, and chronological data from Bermúdez (1989), Sepúlveda et al. (2007), Ramos et al. (2012) and Litvak et al. (2015).