This book analyzes the Early Cretaceous volcanic processes in Misiones Province and in Sierra
Chica de Córdoba (Argentina). The volcanism in Misiones is tholeiitic and belongs to the Parana
Magmatic Province (PMP) which extends throughout South America. In contrast the volcanism in
Córdoba is geographically restricted and of alkaline nature representing a potassic locality
peripheral to the PMP. To understand the causes of and geodynamic processes involved in these
volcanisms a new 40Ar 39Ar of 129.6 ± 1 Ma of a trachyte from Sierra Chica de Córdoba is
presented. This dating points out that the volcanism in Sierra Chica de Córdoba slightly
postdates PMP lavas. Moreover complementary geochemical analyses from Misiones Province are
presented and compared with those from the whole PMP in order to characterize its source
