Reconstrucción de la vegetación y del clima de los pastizales pampeanos durante el Pleistoceno tardío - Holoceno a través del análisis palinológico

ALDO R. PRIETO; ISABEL VILANOVA; MARCELA S. TONELLO; SILVINA STUTZ

Quaternário do Rio Grande do Sul: integrando conhecimentos. Monografias da Sociedade Brasileira de Paleontologia

Sociedad Brasileira de Paleontologia

Lugar: Porto Alegre, RS Brasil; Año: 2009; p. 107 - 120

To reconstruct the late Pleistocene-Holocene vegetation and climate for the Pampa grasslands we reviewed 23 palynological records that have dating control and reliable pollen assemblages located between 34º - 39º S and 56º - 62º W. Five key proxy records were selected to illustrate the local and regional vegetation response to the climatic variability, the sea level fluctuations and the human impact. Vegetation history of the Pampa grasslands was mainly conducted at alluvial sequences since records from shallow lakes (?lagunas?), estuaries and continental shelf are scarce. In spite of differences in temporal and spatial resolution, the data  allowed to evaluate the response of the vegetation to different forcings. Results of this study show (1) Changes in annual and effective precipitation, affecting the hydrology of the region during the late Pleistocene Holocene, (2) Sea level variations as the main forcing affecting the coastal vegetation and the paleosalinity trends between 6500 and 4000 14C years BP without dismissing a climatic forcing before 4000 14C years BP, (3) Development of extensive salt marshes along the southeast coast during the mid-Holocene, a totally different situation to the present one, and (4) An accurate correlation between human impact  on vegetation and documentary records over the last ca. 300 years