Journal of Radioanalytical and Nuclear Chemistry, Vol. 269, No.2 (2006) 441–445 0236–5731/USD 20.00 Akadémiai Kiadó, Budapest © 2006 Akadémiai Kiadó, Budapest Springer, Dordrecht Determination of trace elements in archaeological ceramics and application of Kernel Density Estimates: Implications for the definition of production locations J. O. Santos, 1 * C. S. Munita, 1 M. E. G. Valério, 2 C. Vergne, 3 P. M. S. Oliveira 4 1 Laboratório de Análise por Ativação Neutrônica, Instituto de Pesquisas Energéticas e Nuclerares, IPEN/CNEN, C. P. 11049, 05422-970 São Paulo, Brazil 2 Departamento de Física, Universidade Federal de Sergipe, São Cristóvão, Brazil 3 Museu Arqueológico de Xingó, MAX/UFS, São Cristóvão, Brazil 4 Instituto de Matemática e Estatística, USP, São Paulo, Brazil (Received April 6, 2006) Chemistry fingerprint of materials helps determine provenance and technological production techniques, and, therefore, is useful way to study interaction between prehistoric people. In this work 38 ceramic fragments from Justino and São José sites, in Brazilian northeast, were analyzed using instrumental neutron activation analysis (INAA). The recognition of the compositionally homogeneous group within of the database was performed by means of principal component (PC). The PC scores were calculated on the matrix covariance of the log base 10 transformed concentration values, and grouping was sought in the PC scores using Kernel Density Estimates (KDE). By using KDE from PC scores two chemically different groups were found. Discriminant analysis was performed to assess the groups’ validity. Despite of the pottery from Justino and São José sites present same technical profile, different of the Tupiguarani and Aratu traditions, it was obtained that Justino and São José samples are constitute of distinct ceramic pastes. This result can be understood in terms of the cultural influences in the preparation of the ceramic past and that potteries analyzed are originate locally. Introduction The chemical analysis of pottery is an important aspect of prehistoric and historic archaeology. 1–3 Pottery was probably the first synthetic material made by humans, and thus broken pottery fragment are among the most common artifacts found at archaeological sites around the world. As a consequence, pottery is one of the materials most often studied by archaeologists. Several studies have showed the efficiency of archaeometric techniques based on physiochemical properties of the raw material that composes the ceramic. 4–7 The application of archaeometric techniques has aided in determining the provenance and technology of ceramic production, and, therefore, are useful techniques for reconstructing trade habits and interaction between prehistorical people. 8 In Northeast areas of Brazil several regional traditions according to morphological or stylistic criteria of ceramic artifacts were identified, without explanation of the socioeconomic characteristics of groups’ ceramist and its ethnic affiliations. 9 In agreement with these criteria two traditions widely present in the area were established – the Tupiguarani and Aratu traditions. Recent study, however, has suggested the existence of independent groups, without relation with these two main traditions, thus demanding more studies to support existence of the unknown, independents traditions in the area. 10 * E-mail: josantos@ipen.br In this work, 38 ceramic fragments from São José and Justino archaeological sites in the Brazilian Northeast were analyzed using instrumental neutron activation analysis (INAA) and the concentration of 24 chemical elements was determined. Justino and São José sites are located in Canindé of São Francisco city, in the area of Baixo São Francisco about 150 km from Aracaju, capital of Sergipe State, Brazil. The archeological studies based on the ceramic typology have showed that the pottery from these sites has same technical profile. 11 The local pottery found at sites Justino and São José was used basically for storage and cooking of food, as well as funereal urns. In this work, 17 samples were collected at depth of 150 cm (phase 15, each 10 cm of the depth corresponds one phase) of depth in Justino site and 21 samples from São José site (several depths). In order to interpret data set PCA, DA and KDE 12 were used with the purpose to supply more information in support of a new hypothesis about the penetration of different prehistoric groups, which were neither the Tupiguarani nor the Aratu traditions, in the Northeast of Brazil. Experimental Instrumental neutron activation analysis Although several chemical methods have been employed to analyze pottery and clays, including atomic absorption spectroscopy (AAS), X-ray fluorescence