Cultural and technology elucidation of the Tupi-Guarani tradition through analysis of potsherds from Travessão do Rio Vermelho site (Santa Catarina - Brazil) by spectroscopy, SEM-EDS and chemometrics.

ABSTRACT

Ceramic fragments can provide an insight into the ancient culture and practices of groups of humans and their way of life (technology, cultural identity, social organization, habitation and economy). Scientific analysis can be used to obtain information on the ceramic production process, as well as the specificities of the material employed. In this research, all samples of archaeological potsherd from the Tupi-Guarani tradition were analyzed in order to identify and to characterize the structures, morphologies and the elemental composition by using by scanning electron microscopy (SEM-EDS) and multivariate statistical methods (PCA and HCA). FTIR spectroscopy revealed the presence of an organic residue in three samples along with carbonates, clay minerals, quartz and hematite. In addition, the presence of the stretching attributed to water molecules in crystalline systems was observed. Also, the presence of TiO2 in the anatase polymorphic form was detected using µ-Raman spectroscopy. These results indicate a firing temperature of between 800 and 1000 °C. In relation to the morphology, all samples revealed amorphous structures presenting isolated and heterogenic particles of different forms and sizes, and the EDS spectrum confirmed the elements present in the molecular structures elucidated by vibrational spectroscopy. The multivariate analysis has confirmed the correlation between the elemental compositions of ceramics collected from two different sites a mountain region and a coastal area in Santa Catarina State, Brazil.