CICTERRA   20351
CENTRO DE INVESTIGACIONES EN CIENCIAS DE LA TIERRA
Unidad Ejecutora - UE
artículos
Título:
Mississippian volcanism in the southern Central Andes: new U-Pb SHRIMP zircon geochronology and whole rock geochemistry
Autor/es:
MARTINA F.; VIRAMONTE, J.M.; ASTINI, R.A.; PIMENTEL, M.M.; DANTAS, E.
Revista:
GONDWANA RESEARCH
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2011 vol. 19 p. 524 - 534
ISSN:
1342-937X
Resumen:
In the northern extension of the Famatina and the southern Puna (NW Argentina) prominent rhyolitic
volcanic rocks traditionally referred to as Ordovician are exposed, resting on metamorphic basement and
covered by thick Late Paleozoic siliciclastic successions. We report new UPb SHRIMP ages from these
rhyolites that show them to be of Mississippian (348342 Ma) age, thus identifying a previously unknown
volcanic event in this portion of western Gondwana. Whole-rock geochemistry and SrNd isotopic analyses
suggest a crustal source for these rocks but with a juvenile input (εNd(t) between −2.91 and −0.3, and TDM
values between 1.09 and 1.1 Ga). This is different from the Early Paleozoic magmatism of western Argentina
where crustal recycling took place without any involvement of mantle material. The Carboniferous
magmatism is compatible with an extensional environment developed along the Terra Australis accretionary
orogen as a result of tectonic switching processes. These rhyolites may be related to the coeval Mississippian
A-type granites exposed to the east, in the Sierras Pampeanas, confirming the regional character of this
magmatism.