Late Cenozoic Extension and the evolution of the Neuquén Andes

Abstract

The eastern slope of the Andes between 36ºS and 39ºS shows contrasting behavior north and south of 37.5ºS to 38ºS.The region is notable for a mixed contractional and extensional tectonic regime in the last 5 Ma that has led to the formation of four broad extensional depocenters and the Guañacos fold and thrust belt.The post late Miocene tectonic evolution of the eastern slope of the Andes south of 37.5ºS has been dominated by the development of the Bío Bío-Aluminé and the Loncopué troughs whose extensional collapse is associated with abundant mafic volcanism.