Neuquén foreland basin dynamics: an approach from source analysis based on detrital zircons, Argentina

RAMOS VÍCTOR; DI GIULIO ANDREA; NAIPAUER MAXIMILIANO; FOLGUERA ANDRÉS; PIMENTEL MARCIO

Brasilia, Brasil

Simposio; VII Sputh American Symposium on Isotope Geology; 2010

Universidad de Brasilia

The new U/Pb (SHRIMP and LA-ICP-MS) data provide robust evidence to recognize an early retroarc stage of thermal subsidence without exhumation of the magmatic arc, when the detrital zircons have dominant provenance from the cratonic areas of the foreland. These sources are exclusive during the sedimentation of the Mendoza and Bajada del Agrio Groups beneath the unconformity, until the top of the Early Cretaceous. Exhumation of the magmatic arc related to the early uplift of the Andes is detected at the base of the Neuquén Group, although on a present narrow belt at the foothills of the thrust front. Most of the basin records a cratonal derivation at the time of deposition of the Neuquén Group. The relative narrow belt with Andean derivation is interpreted as a consequence of significant cannibalization of the Neuquén Group as a result of an important phase of deformation, previously to the sedimentation of the Malargüe Group.