Paleoenvironmental studies in Barrancas, Jujuy Province, and its implications for human occupations (ca. 11 000 -5000 BP)

BRENDA OXMAN; HUGO D. YACOBACCIO; LILIANA C. LUPO; P. TCHILINGUIRIAN

Conferencia; 4th Southern Deserts Conference; 2014

Laboratorio de Paleoecologia Humana. Universidad Nacional de Cuyo

The first paleoenvironmental results fromBarrancas are presented. This place is known forthe great number of archaeological sites in thedry Puna of Jujuy, mainly for the large numberand diversity of rock art designs. This research ispart of an archaeological andpaleoenvironmental research project thatdisseminates knowledge to the local community.The area is located in the Argentine Puna in ansemi-arid area where mean rainfall is around 250mm per year in the summer. The studied sites arein alluvial fillings on terraces of the Barrancasriver.Analyses were done of the geomorphologicalsetting and the sedimentary and pollen recordsof a sediment core from Cruces (23°18?S, 66°5?W,3700 masl). Chronologic control consists of three14C ages: 11650±62 (AA-103187), 5919±42 (AA-103191), and 4865±37 (AA-103192) BP. A total of25 pollen taxa have been identified to the levelof species, genus, and family. Preliminary resultsindicate two main paleoenvironmental scenarios.Zone 1 (between < 4800 and 5024 BP), showshigh and constant values of Poaceae whileAsteraceae decreases, accompanied by highdominance index. Zone 2 (between 5198 BP and>11,650 BP) shows higher proportions ofAsteraceae and a higher diversity index. Amoisture index indicates that the dry episodesbecame more regular, marking overall drierconditions. Post-4800 BP changes are abrupt andthe average moisture content was higher thanregional conditions.The pollen data are consistent with the faciesand sedimentologycal record. After 4800 yearsBP, sediments are thicker and present fewerpaleosols and more erosional disturbances,indicating more environmental instability andscarcity of biomass and moisture to form soils.This results indicate significant variation in thevegetation which would be interpreted as amore humid and stable environments followedby a more arid and unstable phase. Based on thispaleoenvironmental information, hypotheses forhuman occupation can be generated.