Cenozoic foreland basins of Central Andes: a preliminary provenance U-Pb zircon analysis of sedimentary sequences of Calchaquí Valley, NW Argentina

OLIVEIRA, A.L.; HAUSER, N.; GALLI, C.I.,; PIMENTEL, M. ; MATTEINI, M.,; COIRA, L.B.; ALONSO, R.N.,; BARRIENTOS, A.

Brasilia

Congreso; XV Congresso Brasileiro de Geoquímica.; 2015

Sociedad Brasilera de Geoquímica

The Eocene of northwestern Argentina records complex basin and structural evolution, including continental sedimentation of the post-rift Salta Basin and the beginning of the Andean uplift and foreland system evolution. This illuminates a significant period of evolutionary history of this and surrounding basins in northwestern Argentina. U-Pb zircon analyses by LA-ICP-MS for three formations representing post-rift to foreland stages allowed interpretation about provenance terrains. The Lumbrera Formation, representing the post-rift stage, shows bimodal sources with a main zircon population around 462 Ma, and a second population around 1023 Ma. The Los Colorados and Angastaco Formations representing the sedimentation in a foreland basin, show a unimodal source around 490 Ma, and 517 Ma respectively. Zircons younger than 50 Ma were not identified during this study.