CONICET | Buscador de Institutos y Recursos Humanos

In north-western Argentina (Jujuy province), Coctaca and Rodero sites are known for the ample ancient fields with structures specially prepared for agriculture, which significantly diverge from similar settlements throughout the Andes. The site extends for about 4000 ha., occupied by stone structures. The archaeological landscape is formed by longitudinal irregular lines of field clearing heaps and, between these lines, narrow stone-walled agricultural enclosures made of simple, double, or double filled stone high walls (that may surpass 2 meters high). These structures are surrounded by irrigation canals. Although the beginning of the occupation has not been established yet, Albeck (1995) proposed two moments concerning the construction of the agricultural enclosures. While the last moment completely coincides with the Inka occupation, the oldest segment - sampled for this occasion- could have preceded several centuries the last stage of construction. The functionality of these enclosures has been object of a long debate. Albeck (1986, 1995, and 1998) and Albeck and Scattolin (1991) suggest that they had been used for agriculture, producing a moderating effect in the local microclimate. The high walls reduced the drying effects of the wind, and by increasing the temperature they facilitated the growth of vegetation inside the enclosures. Following these ideas, we started a microfossil research to understand the functionality of the structures (Maloberti et al 2005). The objective of this investigation was principally the identification of phytoliths corresponding to domesticated vegetal species, making special emphasis in Zea mays sp. (Maloberti et al 2007). The extraction of phytoliths and other microfossils followed the methodology for multiple microfossil extraction (Coil et al 2003), but since mays phytoliths were not found, some samples were sent to Uniceps Uruguayan laboratory as blind test inter-laboratory control, and therefore another protocol was used for phytoliths separation and identification. At present we are following a new fieldwork and laboratory methodology for this study area and this problem, which attempts an interdisciplinary integration of data (archaeology, phytoliths, diatoms, pollen and soils). In this sense, first pollen data show different preservation - while the sediments with basic pH are the best for pollen conservation- enhancing the presence of the natural vegetation that is dispersed at a regional scale (bushy steppe- Prepuna).