Morfologia, química e mineralogia dos solos antrópicos no cerrado amapaense: o Sítio AP-MA-05 no Campus Universitário Marco Zero do Equador, Macapá-Amapá

Abstract

Recent pedological, archaeological, and ethnographic research has brought new insights into the interrelationship between man and the environment. The study of the morphological, chemical and mineral composition of the soils applied to archaeological sites reveals that activities performed in the same place, under a determined time, leave different chemical signatures in the soil. And the study of these soils becomes relevant to a better understanding of human presence in areas of former settlements. Thus, this research aimed to characterize the morphological, physical, chemical and mineralogical aspects of the anthropic soils of the AP-MA-05 site, seeking to point out particularities of the past occupation in the cerrado Amapaense. The study area is located on the campus of the Federal University of Amapá (UNIFAP), in the municipality of Macapá-AP. To reach the objective, soil samples were collected in two transverse, perpendicular to each other, that obeyed the North-South and East-West directions. After collection, the samples were prepared and submitted to the characterization laboratory analysis through granulometric analysis; verification of chemical parameters, measured by determination of pH in water, available P, exchangeable Ca, Mg, K and Al and H + Al; mineral identification was performed by X-ray diffraction. Two soil profiles were examined for their morphological properties, one in the site area and the other in the adjacency, for comparison purposes. Lateritic spots at the archaeological site AP-MA-05 did not present a clear pattern of distribution, but attested its anthropic appearance, as well as its influence on the formation of archaeanthosols. Through the morphological characterization, the areas with the greatest influence of the prehistoric anthropic activities were identified by the darker coloration of soils classified with bruno color and thickening of the A horizon, which can exceed 20 cm of thickness. The granulometry showed sandy soils, which favor the erosive process, however, in soils of transverse 1 there is a greater accumulation of the argiloarenoses fractions as a result of the anthropic occupation process, which reduce its leaching and erosion process. The mineralogical composition did not express difference between the soils of the archaeological site and its adjacent area, inferring that both have the same mineral matrix of origin with predominance of quartz and kaolinite, and that the modifications are of anthropic character. The chemical variability showed the heterogeneity of the soils of the archaeological site, originating from the influence of the previous human activities. The increase in fertility observed through the highest concentration of Ca, Mg and K occurred in the South direction of the site, evidencing the area of preferential deposition of residues, reflecting the dynamics of the anthropic action in the settlement. The chemical and morphological composition of the soils presented shows the growth of the site in the southern portion and outside the limits established in previous research. The archaeanthostrosols in the site are evidenced by the dark coloration of the soils, thickening of the A horizon and their high fertility, however, despite these similar properties, they are distinct from the classic black archeological black found in other states, mainly by phosphorus content and addition of lateritic layer