Paleoecología del Cuaternario Tardío en el Sur de la Patagonia (46º-52º S), Argentina

Resumen

This article is a review of pollen studies from stratigraphical sequences of Pleistocene and Holocene age with the aim to reconstruct changes in the different types of vegetation and, by inference, of paleoclimatic conditions between 46º and 52º S (Argentina). The paleoenvironmental interpretation is based on comparison of the fossil pollen data with modern pollen data and their relation to the vegetation and the climatic conditions of the study area. Most of the records are of postglacial (Holocene age), only two sequences represent the Middle and Late Pleistocene; the former from the upper valley of the Santa Cruz River and the latter from the area of the Straits of Magellan. Due to the different stratigraphical and sampling resolution of the sequences, the vegetational changes are not evident in all the records. However, the comparison of the sequences at regional scale permitted to evaluate the response of the plant communities to the climate change. The history of the vegetation inferred from these records reflects different processes such as climate change, forest dynamic and human impact. From the interpretation of the available records, the presence of a vegetation without modern analogues is found during the Middle Pleistocene represented by forest dominated by Podocarpus and during the Late Glacial with its dry steppe. Modern vegetation became established at the beginning of the Holocene with the expansion of open forests of Nothofagus. Modern vegetation distribution only developed during the Late Holocene.