Ionic relations: A tool for studying hydrogeochemical processes in Pampean shallow lakes (Buenos Aires, Argentina)

Abstract

Main geochemical processes that determine the chemical composition of shallow lakes in the lower Salado River basin were studied. The region is characterized by the total lack of slope and the succession of humid and dry climates where the lakes are shallow alkaline and eutrophic ecosystems, with circulation pattern corresponding to polymictic lakes. Gibbs classical diagrams confirmed that weathering of mineral phases and evaporation-crystallization were the principal processes involved. Nevertheless, deviations to the basic pattern were observed. The study of ionic relations (in meq l-1) determined that a cationic exchange process takes place in the Pampean loessic sediments, influencing the chemical characteristics of both groundwater's and surface waters.