LATE PLEISTOCENE–HOLOCENE SEDIMENTOLOGY OF THE MIDDLE SALTO-ARRECIFES FLUVIAL BASIN. REGIONAL CORRELATION AND STRATIGRAPHICAL MODEL FOR THE PAMPA ONDULADA, ARGENTINA.

Abstract

In order to contribute to the knowledge of the paleoenvironmental and paleoclimate evolution that occurred from the Late Pleistocene to the Late Holocene in the Pampa Ondulada, northeast of the Province of Buenos Aires, the results obtained by interdisciplinary research carried out in the Salto-Arrecifes fluvial basin are presented. These results were integrated and correlated with those published by some authors of this work referring to the geological and paleoecological characteristics that dominated the valleys of this sector of the Argentina Pampas region since the Late Pleistocene. The age of the sedimentary successions was obtained by radiocarbonic dates in 10 locations of the Salto-Arrecifes fluvial basin. Regional correlations with the units described for the Luján and Areco river basins were carried out. Those characterize the sedimentary processes that occur in the current valleys, of the lower-middle basins of these courses. The various sedimentary facies present in the continental sectors and in the sections closest to the river’s mouth are discriminated. The Late Pleistocene–Holocene sedimentation, which occurred in the middle Salto-Arrecifes, Luján and Areco basin, shows the incidence of climatic changes during the period. As for the facies recognized in the sections near the river’s mouth of the courses, the incidence of eustatic changes produced during the current interglacial were added. Exposure in the ravine of deposits that have the oldest recorded ages and that occurs only in some stretches along the current valley could indicate that neotectonics has been another extrinsic factor acting in the basins at some point in the Late Holocene.

Keywords

• Pleistocene–Holocene
• Stratigraphy
• Fluvial basins
• Undulate Pampa
• Paleoecology