Caracterização geoquímica das áreas hipersalinas sob influência do alto curso estuarino Apodi-Mossoró

Geochemical characterization in the hypersaline areas under the influence of the upper Apodi-Mossoró estuarine course

Abstract

The fluvial-marine plains are environments closely related to continental and oceanic factors, since they are located in coastal zones and form high salinity soils. In the northern area of ​​Rio Grande do Norte (RN), due to the geomorphological and climatic conditions, these plains are characterized as hypersaline environments. The fluvial-marine floodplain of the Apodi-Mossoró River is located in the estuarine zone, with flattened areas and impermeable soils that favor the damming of river and marine waters. In this research, the geochemical conditions of the soil were investigated in the upper estuarine course located in the Brazilian semiarid region; for this, soil samples were collected with different depths in different hypersaline environments. The laboratory analyzes indicated a soil with high concentrations of Na⁺, Ca²⁺ and Mg²⁺, presenting sodic classification, salic character and moderately alkaline condition; these characteristics reflect the influence of the semiarid climate and progressive evaporation of sea water in the supratidal area, favoring the precipitation of salts in the upper estuarine course. The granulometry of the sediments, in turn, indicated the predominance of finer particles such as silt and clay in the textural composition of the soil.