ABSTRACT
A Holocene paleoenvironmental reconstruction of part of the Argentine loess region has been performed on the basis of pollen analysis of discontinuous loess sequences from site 3 of an archaeological site, Cerro La China (lat.37° 57’S, long. 58. 37’W).
Multivariate analysis of pollen sequences from two profiles was accomplished to test correlations between these two pollen records and to identify similarities among the lithostratigraphic units; sediments were deposited episodically and modified by pedogenesis. In order to identify possible buried soil surfaces and to estimate pollen production and sediment accumulation, pollen concentration and percentage curves were compared. Multivariate analysis allowed to determine three pollen units. These groups are ecologically defined in terms of the environment they represent.
The first unit begins at 10,610 + 180 yr B.P. Substantial amounts of pollen from hydrophytic plant communities suggest that the environment could have been wetter than at present. High percentages but low concentrations of long distance pollen and Myrtaceae suggest a comparatively low local pollen productivity. This unit is upwardly limited by an erosive episode. The second unit begins ca. 4500 yr B.P.; pollen records are dominated by grassland taxa characteristic of the Pampas. When compared with the first unit, this suggests climatic changes and /or local variations of the relief surface. The third unit is separated from the second by a slight erosive episode. The high percentages of Compositae and Chenopodiineae pollen are related to dry conditions in the 220beginning of the unit. The local disturbance is reflected in this unit by Cruciferae associated to other ruderal species.
