Human occupations in semiarid environments of the Central Pampa Dunefield during the Early Holocene (Buenos Aires Province, Argentina)

MESSINEO P G; TONELLO M S; SCHEIFLER N A; STUTZ S; NAVARRO D

Mendoza

Conferencia; 4th Southern Deserts Conference; 2014

The aim of this paper is to integrate archaeological,geoarchaeological, chronological, and paleoecological information related to human occupations in semi-arid environments of the inland Pampas during the early Holocene. We present the analysis of several lines from a paleoecological perspective of evidence (paleoclimatic reconstructions, geology, faunal, and techno-morphological studies) from the site Laguna Cabeza de Buey 2 (San Carlos de Bolívar District, Buenos Aires Province, Argentina). This site is located on the eastern edge of the aeolian unit called the Central Pampean Dunefield, which is characterized on the basis of its geomorphological features and geological and structural settings. The main landforms are linear dunes, 100?130 km long and 2?3 km wide, with a general north?northeast trend and a height of around 2 m. Dune orientations suggest paleowinds from the southwest during the Pleistocene. Pollen records indicate sub-humid to humid climatic conditions at beginning of the Early Holocene in this area and changing toward slightly drier conditions between 9000 and 7000 BP. This dry phase is also suggested by faunal records and isotope analyses. The Cabeza de Buey 2 site is represented by four human occupation events, starting in stratigraphic unit IV and the early Holocene (∼7000 BP). The texture studies carried out in unit IV suggest a loamy sand deposit with the presence of subordinated carbonates. The faunal assemblage is comprised of skeletal remains of the ungulates Lama guanicoe and Ozotoceros bezoarticus, an extinct mega-mammal (Toxodon sp.), and some small mammals species such as armadillo (e.g., Chaetophractus villosus, Zaedyus pichiy, and Tolypeutes matacus) and rodents (Ctenomys sp., Akodon sp., and Reithrodon sp.). Among the identified species, the camelid Lama guanicoe presents clear evidence of human modifications (e.g., cut marks and burned bones). The habitats required by these taxa suggest the presence of environments with well- drained soils and a relatively homogeneous grassland. In addition, the ecological significance of most vertebrate fauna and the pollen record suggests that this environment had a warm and semi-arid climate. Three types of lithic raw materials were recorded, predominately quartzite (∼55%) and chert (∼43%), whereas silicified dolomite was found in low frequencies (∼2%). All of the materials are non-local and come from the Tandilia Hill System more than 100 km to the east. Techno-morphological analysis suggests that the last stages of the stone-tool reduction sequence were carried out at the site, mainly resharpening of quartzite and chert tools. This site may correspond to a locus of specific activities related to the processing of animals such as Lama guanicoe during the early Holocene in the Central Pampean Dunefield.