Aspectos sedimentológicos y estratigráficos de los depósitos cuaternarios de la costa platense del Departamento de Canelones (Uruguay) Sedimentologic and stratigraphic aspects of the Quaternary deposits along the Plata Coast on the Departamento de Canelones (Uruguay)

Esta contribución brinda elementos sedimentológico-estratigráficos de los depósitos cuaternarios que aparecen en los acantilados y plataformas en la costa rioplatense del Departamento de Canelones, Uruguay. Se constató la presencia de depósitos regresivos e ingresivos cuaternarios, materializados por los sedimentos pleistocénicos transicionales de la Formación Chuy y los continentales de las formaciones Libertad y Dolores, así como los transicionales holocénicos de la Formación Villa Soriano. Se caracteriza litológicamente cada unidad, se interpretan los procesos actuantes y se hacen inferencias acerca de los ambientes de sedimentación involucrados. The Uruguayan Quaternary record has been studied by several authors in the last four decades. The Quaternary glacial and interglacial record shows a few tens meters of thickness and is integrated by both sediments and non-depositional surfaces. The sedimentary package is better exposed in the southern region and coastal area of Uruguay. The non-depositional surfaces (iron crust) and paleosoils are better exposed in the north and eastern region. The Lithostratigraphic column proposed by Goso (1965, 1972) focuses the Quaternary record with a precursor genetic point of view, integrating lithologic, geomorphologic and climate conditions. However, this stratigraphic proposal was partially adopted and understood by some scientists. Transitional sediments of the Pleistocene Chuy Formation and continental deposits of Libertad and Dolores formations are present. Also, transitional Holocene sediments of Villa Soriano Formation were shown and are described (Fig. 1). The goal of this paper is to contribute to the knowledge of a part of this record especially towards some sedimentologic and stratigraphic features of the Quaternary deposits exposed along Rio de la Plata coast in the Canelones Department, Uruguay (Figure 2). The Chuy Formation is very well exposed in Villa Argentina and Las Vegas - La Floresta beaches. It is integrated mainly by white conglomerates and coarse to fine sandstones with current and wave traction structures and trace fossils. Also contains fossiliferous green clay deposits. It looks with variable thickness since a few meters to twenty five meters (Figs. 3 and 5). It was deposited during an interglacial period in transitional sedimentary environment, predominantly the shoreface portion in a barrier island and lagoon systems, into tidal conditions. The top of this lithofacies sequence shows a thin (few centimetres) iron crust in the area. This non-depositional surface was also observed in others i