Neogene sediemntation in the Argentine foreland between 34 30 y 41 S and its relation to the Andes evolution

ALICIA FOLGUERA; MARCELO ZÁRATE

Cenozoic Geology of the Central Andes of Argentina

Instituto del cenozoico Universidad Nacional de Salta

Lugar: Salta; Año: 2010; p. 121 - 132

This contribution examines the Neogene record of central Argentina with focus on the central part of La Pampa province, and offers a preliminary model of evolution in relation to the Andes tectonics. The sediments, characterized by their Andean derived composition (volcaniclastic) and vast extension, are interpreted as distal synorogenic deposits accumulated between around 12 and 7-6? Ma. On the basis of the geometry analysis of the late Miocene basin, it is inferred that sedimentation took place in an Andean foreland back bulge affected by dynamic subsidence. The central part of La Pampa Province, here defined as a block (La Pampa Central block) is considered to have been upliftedand basculated to  the east with a few meters throw in response to the flat geometry subduction that occurred at this latitude in the late Miocene. The uplift may have also caused the end of the accommodation space north of 38°S and brought about the southward migration of the sediment depocenter during the Pliocene. Keywords: Neogene - Pampa province - foreland basin: Neogene - Pampa province - foreland basin