The mounds of the India Muerta region, Uruguay, as pit oven stations. New data

In the India Muerta-Paso Barrancas region (Rocha, Uruguay) more than 600 prehistoric mounds have been identified. The archaeological record of these terrestrial structures includes integrated residues of human activity: bone remains, lithic and bone artifacts, charcoal, ochre, a small number of ceramic fragments and human burials. But the most outstanding characteristic of these structures is that they are mounds of thermoaltered sediment. Between 25 % and 30 % of their matrix are fragments of anthills that reaching 6 cm or more in their largest dimension and that were heated to minimum temperatures of 350/380ºC. This work presents a battery of TL and OSL dates carried out on the thermoaltered sediment of the highest and oldest mound structure in the region, known as “Cerro de la Viuda”. The data obtained with the two techniques are compared, along with 14 C chronologies from the same mound. The correlations between the dates obtained and the daily processes that would have led the prehistoric groups of the region to produce, over centuries, of mounds of thermoaltered sediments are analyzed and interpreted. This is a contribution to the understanding of the chronology and function of anthropogenic mounds in the India Muerta-Paso Barrancas region. The data presented support the hypothesis that the sampled clasts were heated in situ and therefore that the mounds were built in association with earth ovens.