Study of Ancient Pottery from the Brazilian Amazon Coast by EDXRF, PIXE, XRD, Mossbauer Spectroscopy and Computed Radiography

This paper presents the application of five analytical methods to analyze ceramic fragments excavated in the archaeological sites of Sambaqui do Bacanga (SB), Sambaqui da Panaquatira (SP), and Rabo de Porco (RP) located on the Brazilian Amazon coast. It is a region that presents evidence of one of the oldest ceramic productions in the Americas. Characterization of ceramics from the three sites led to the identification of the production processes, technological acquisition and choices, and the origin of the raw materials. The analytical methods employed in this study were EDXRF, PIXE, Mossbauer spectroscopy, XRD, and computed radiography. It was concluded through the Mossbauer and XRD Spectroscopy analyses that the firing temperature range used on the ceramics was 750-900 degrees C, performed in an oxidizing environment. Fragments from the three archaeological sites were grouped into two groups through multivariate statistical analysis. The first group was composed of SB and SP samples, and the second of RP samples, indicating that different groups were manufactured with different clays. The result of the cluster analysis indicates that the clay used in the manufacture of the RP site fragments came from the bank of the Bacanga River. The ceramic fragments' internal structures, observed by computed radiography, revealed the presence of various sizes and types of temper in the fragments, showing different production technologies.