INSUGEO   12554
INSTITUTO SUPERIOR DE CORRELACION GEOLOGICA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
LA-ICPMS U-Pb Provenance data for detrital zircons of Cambro-Ordovician units of the Qubrada de Humahuaca, Jujuy Province, Argentina: Tectonic significance
Autor/es:
DI CUNZOLO S. C., Y PIMENTEL M. M.
Lugar:
San Carlos de Bariloche, Argentina
Reunión:
Simposio; VI-SSAGI; 2008
Resumen:
In this contribution  we discuss preliminary U-Pb LA-ICPMS results for detrital zircons from sandstones samples collected in two sections located in the Chucalezna and Purmamarca localities, in the middle sector of the Quebrada de Humahuaca, Jujuy Province Argentina. The main objective, is to investigate the provenance of these Cambrian-Ordovician sediments (Casa Colorada Formation, López & Nullo, 1969), in order to contribute to the paleogeographic interpretations of the western margin of Gondwana. The Cambrian-Ordovician sequence has been interpreted as deposited on an intracratonic basin with a submeridional shape developed along the Early Paleozoic Gondwana margin. The studied samples are sandstones from the Lower section of Casa Colorada Formation. Detrital zircons age patterns  display mainly Neoproterozoic ages (0.62-0.92 Ga), with a subordinated Mesoproterozoic (1.07-1.57 Ga) population. A small Paleoproterozoic population (1.61-2.36 Ga) is also observed. Archean zircons, were identified in Chucalezna section, with an older peak at 3.4 Ga (Paleoarchean) and a younger at 2.9 Ga (Neoarchean). This contribution represents the first U-Pb LA-ICP-MS provenance analysis for Cambrian-Ordovician sedimentary rocks in the region; and support a Gondwana origin for the original sediments, with ages ranging from Archean (3.4 Ga) to Lower Neoproterozoic-Lower Cambrian (0.62-0.52 Ga).