Multifactorial analysis of the geochemical characterization in a Brazilian hypersaline floodplain

Abstract

Hypersaline floodplains (sabkhas or saltflats) consist of the supratidal plains with low input of clastic sediments, high evaporation rates, and crustal salts. These environments are prone to periodical floodings and evaporite deposition, common in coastal areas with flat topography of arid regions, developing in response to two environmental conditions: deflation of surface sediments, or accumulation of sediments in a lake, or by a combination of both processes. This research developed a geochemical and textural characterization in soil samples collected in the estuarine floodplain (367.7 km2) of the Apodi-Mossoró River (Northeastern coast of Brazil), analyzing the results using multivariate statistics. The cluster and PCA analyses applied to the set of sampled sites enabled to identify two zones typical of the estuarine plain, as well as the major groups of parameters related, being one with the greater direct influence of tides (lower estuary) and another, upstream. This is a result of the a gradual accumulation in the soil (mainly the sodium), after the flood period in the spring tides, followed by a rapid water evaporation caused by high temperatures (>30°C) and constant winds.