MODERN POLLEN AND VEGETATION IN THE LOW BASIN OF COLORADO RIVER, SOUTHWEST OF BUENOS AIRES PROVINCE, ARGENTINA

In order to determine modern analogues for fossil pollen sequences associated with archaeological sites in the lower Colorado river basin (southwest of Buenos Aires Province), the modern pollen-vegetation-climate relationships were evaluated. The study conducted through vegetation samples, pollen percentage diagrams and cluster analysis included surface samples, located at the northern and southern parts of the basin. Six plant communities (halophyte steppe, xerophytic woodland, grassland with xerophytic woodland elements, ruderal, halophiles/gramineous grassland and hydrophytic) were determined. The pollen spectrum was dominated by Chenopodiaceae, Asteraceae, Brassicaceae and Poaceae families. Most of the vegetation and pollen reflected the local communities as part of the Espinal Province (Calden District), recording a greater influence from the Pampean region (Pampas grassland-Espinal ecotone) under sub humid-dry weather at north of the basin, and greater influence with the Monte Province (Monte-Espinal ecotone), linked to semi-arid climatic conditions to the south. Non-pollen microfossils (spores of fungi and algae) and taphonomic analysis complemented the study.