Análise de elementos químicos em solos da região de Caxiuanã-PA

Abstract

The Ferreira Penna Scientific Station is located in the Caxiuanã National Forest (FNC), municipality of Melgaço-PA. This area is a cradle of research in various areas of knowledge by both national and international institutions. In Caxiuanã several archeological sites have been found, where most of them have soils known as Terra Preta Arqueológica or Terra Preta do Índio. These soils have a black coloration, archeological material (pottery fragments and lithic material) and a high natural fertility, currently sought after by riverbank dwellers for homesteading or cultivation. The texture of these soils is physically sandier and their structure stronger than adjacent soils. The present work aims to make a comparative study of the chemical elements Ca, Mg, Zn, Mn, Pe and C in the horizons (AI, AB, BA and B1) of a soil profile from the Ilha de Terra site with other sites and their adjacent areas and the classification of the shells occurring in the Caxiuanã region. The soil samples were pulverized and passed through a 2mm sieve and are being processed in the chemical analysis laboratory of the Geosciences Center of the Federal University of Pará, where Ca, Mg, Mn and Zn will be determined by atomic absorption spectrometry and P by colorimetry. According to results found in the literature, these elements decrease their content with depth, with a significant difference between the AI and B1 horizons. The malacological content of the IBAMA and Forte sites is composed of shells of gastropods (terrestrial) and bivalves (dulçaquicola). Some species presented elongated oval shell, transversal, not very solid, rounded anterior and posterior edge, yellowish white color, with separate concentric striations, white interior and constant valvulae; others presented solid, oblong, transversal oval, convex, curved shells, between open valvae, rounded anterior edge and wide posterior edge. These mollusks live in lake environments, rivers, and sometimes endure stagnant conditions.