SciELO - Scientific Electronic Library Online

vol.35 número2Deformación compresiva cuaternaria en la Cordillera Principal de Chile central (Cajón del Maipo, este de Santiago)Ambientes depositacionales y potencial oleogenético de la Formación Los Molles, Jurásico Medio de la Cuenca Neuquina, Argentina: palinofacies y datos de geoquímica orgánica índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados




Links relacionados


Revista geológica de Chile

versión impresa ISSN 0716-0208


EZPELETA, Miguel; ASTINI, Ricardo A  y  DAVILA, Federico. Synorogenic deposits in the late Paleozoic foreland basin of central-western Argentina: paleoenvir-onments, paleogeography and tectosedimentary implications. Rev. geol. Chile [online]. 2008, vol.35, n.2, pp.253-277. ISSN 0716-0208.

In the Famatina belt, western Argentina, a -400 m thick conglomerate succession is extensively developed and has been previously considered as the uppermost section of a postglacial interval (late Pennsylvanian) of the Paganzo Group. Here we separate it as a different lithostratigraphic unit (Las Pircas Formation, nom. nov.) with a significant tectonic meaning based on: 1. the angular discordance at its base; 2. the strong lito facial contrast with the underlying glacial unit and 3. its internal stratigraphic organization. Facies analyses indicate topographically controlled proximal alluvial fans succeeded by braided fluvial systems, and local development of lacustrine deposits. Granite bearing-megaboulder beds and conglomerates indicate significant basement exhumation and tectonic unroofing. Clast composition also depicts early Pennsylvanian sandstones and Ordovician volcanic rocks mainly exposed in the central part of Famatina (at present). Paleocurrent analyses are compatible with a dispersal pattern mostly to the west. The position of basement topographic high further east from the main contemporaneous arc together with evidences of folding allow us to interpret previously unrecognized basement thrusting within the foreland. This may have been the main source for the westward coarse arkosic clastic wedge known in the Argentine Precordillera as the Tupe Formation and equivalents. This late Pennsylvanian-Early Permian foreland model can be compared with the modern broken foreland of the Central Andes.

Palabras clave : Conglomeratic wedge; Synorogenic deposits; Broken foreland; Late Pennsylvanian-Early Permian; Central-western Argentina.

        · resumen en Español     · texto en Español     · Español ( pdf )


Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons