Abstract

SANCHEZ, María L.; ASURMENDI, Estefanía  and  ARMAS, Paula. Río Colorado Subgroup (Neuquén Group): Paleosimicity record in the Andean foreland basin, Neuquén basin, Neuquén y Río Negro provinces. Rev. Asoc. Geol. Argent. [online]. 2013, vol.70, n.1, pp.96-114. ISSN 0004-4822.

The Neuquén basin is located in the central and western part of Argentina and represents the most important Mesozoic-Neogene depocenter in the country and is one of the basins of the Southern Hemisphere with an excellent marine and continental record. It is characterized by three stage of evolution: an initial rift, subduction related to "sag" a state of thermal and foreland basin. The Río Colorado Subgroup is deposited during the foreland development. Subgroup sindepositacional tectonics is recorded by three deformational levels, two in Bajo de la Carpa Formation and one in the Anacleto Formation. They are composed of deformation and liquefaction structures interpreted as sismites. The deformation is represented by simple load structures, balls and pillows, flaming, pseudonódulos, lamination convolute, pinch and swell, slumps, sandstone disorganized, folded sandstone, mud diapirs, fractures, dish and pillar and autoclastic breccias. These deformational structures in the Bajo de la Carpa Formation involves deposits of channel belts and flood plain, while in the Anacleto Formation deposits affects the tidal channels of high and low sinuosity, intertidal mud flats, sandy and muddy plain supratidal associated with an middle estuarine system. The recognized sismitas levels are probably associated with Sierra Barrosa and Lindero Atravesado lineaments and these maybe are dynamic response to the activity of the structures. The nature of the structures and their distribution suggests that the magnitude of earthquakes is greater than 6 on Richter scale.

Keywords : Sedimentology; Deformations; Seismites; Neuquen basin; Paleosismology.

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