CONICET | Buscador de Institutos y Recursos Humanos

The Chaco plain is a sedimentary basin filled by alluvial fans repeatedly generated by large rivers during the late Quaternary under diverse climatic conditions. The Eastern Chaco is characterized by semi-deciduous forests intermingled with extensive palm-savannas, grasslands, and wetlands. These vegetation patterns of the Chaco have been proposed to be the result of the Pleistocene-Holocene alluvial dynamics of the plain as well as of the intensive migration of fluvial belts of the main rivers. In this paper we present silica microfossil records from a Pleistocene-Holocene sedimentary sequence from the Eastern Chaco Region. The results show that phytolith elements were the most abundant compared to the other siliceous and non-siliceous microfossils. The differences in the microfossil associations show that climate changes along the Late Quaternary were given mainly by humidity changes, and that grasslands and wetlands predominated in the described paleocommunities.