Pottery and Archaeometry. Bacabal phase: a study about the occupation in the southwest Amazonia

This work presents an interdisciplinary study focused on the chemical, mineralogical and physical characterization of 84 pottery fragments from the Monte Castelo archaeological site, with the aim of obtaining information about pottery production and cultural variability of human occupation in the upper Guaporé river, southwest Amazonia. The archeometric study was based on four physical analytical techniques: neutron activation analysis (AAN) for determination of elemental chemical composition, X-ray diffraction (XRD) for determination of mineralogical structure, electron paramagnetic resonance (EPR) for determination of the firing temperature and dating by thermoluminescence (TL) for verification of site chronology. The provenance studies performed by AAN were interpreted by multivariate statistical methods, which allowed the definition of three chemical groups of pottery for variations in the TL dating were observed. The TL dating results of some pottery fragments showed that the sheel mound was occupied by the Bacabal ceramic producing culture between around 3000 B.P and 1500 B.P. The mineralogical characterization allowed the verification of kaolinite, illite and smectite in the sediments of the region, besides indicate a range of 500-900 °C for the firing temperature of the analyzed pottery. That it was confirmed by the RPE analysis, where it was possible to observe that the ceramics were burned using probably open pit fires or holes in the ground where the temperature did not exceed 600 ± 50 °C. (author)