Estudo das análises químicas da cerâmica arqueológica e da cerâmica atual do sítio ilha de Terra, em Caxiuanã-PA

Abstract

Studies show that archaeological pottery has high levels of . P, Ca,Mg,Mn and Zn . These elements can be related to the culinary practices of the group that used them or were incorporated later because they were deposited in the soil with Archeological Black Earth, also rich in these elements. ° The present work aims to make an experimental chemical analysis of pottery currently made in Caxiuanã. For this purpose, 7 pots were submitted to a programmed fish-firing. The first pot was cooked 5 times for a period of 30' and the last pot was cooked 35 times also for 30'. After cooking, a fragment of each pan was removed and pulverized to be submitted to chemical and mineralogical analysis, where the following elements and compounds will be analyzed: phosphorous by the Mehlich-Tedesco method (1985) and determined by colorimetry; Ca, Mg, Zn, Mn, Na,O, Fe,Ol and TiO2, in an opening with HF + HCIP04 and determined by atomic absorption spectrometry and AIPl by titrimetry. Mineralogical analysis will be done in x-ray diffraction spectrometer apparatus and quantified based on the chemical analyses using stoichiometric calculations. The raw material used to make the ceramics was clay from within the Curuá river, as it presents good plasticity in relation to that which is found on the banks of the house. The antiplastic used was the bark of the cariape tree (Hyminea courbaril. Mart.), burned and sieved. The proportion of clay to cariape was 3:1; these two components were mixed with water and the technique used was chordel formation, and the pots were dried in the sun for 1 or 2 days, and then burned. The waterproofing was done at the end of the firing, using resin from the Juteica tree. The chemical analyses are being done in laboratories at MPEG and UFPA.