Análisis polínico de un sitio de altura del Holoceno Tardío: Cerro Verlika 1, sudoeste de Santa Cruz, Argentina

María Virginia Mancini

Abstract


The objective of this work is to reconstruct the vegetational changes that occurred in a high Andean site in the south of Santa Cruz province by means of pollen analysis of sediments from the archaeological sequence Cerro Verlika 1 (50° 36' S; 72° 16' W, 1.100 m asl). The new data will contribute
to the palaeoenvironmental reconstruetion of the Lago Argentino area. This site is located in an environment considered Andean Desert, including different sub-desertic to desertie types of vegetation, distributed in a mosaic pattern. The pollen records of the sequence analysed suggest that between ca. 4.500 and 3.600 yr 14C B.P. a grass-shrub steppe expanded, represented by Poaceae, Asteroideae and cushion plants such as Empetrum, Azorella and Bolax, indicating colder and moister conditions than at present. Beginning at 3600 yr B.P. and dominant at ca. 3.000 yr B.P. the vegetation changed to a shrub steppe dominated by Asteroideae, and accompanied by other taxa typical of high-mountain areas; this indicates less availability of moisture and an increase in temperature. This shrub steppe vegetation resembles xerophytic subandean forrnations which nowadays develop below 1.000 m asl. This shrub steppe continued to the uppermost levels the pollen spectra of whieh are dominated by Asteroideae, Poaceae, Azorella, Bolax and Rosaceae resembling modern vegetation near the rockshelter. In these last samples, there is overrepresentation of Brassicaceae, whieh indicates the action of livestock.

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