A comparative evaluation of the CF:CS and CRS models in 210Pb chronological studies applied to hydrographic basins in Brazil.

摘要: Abstract The Constant Flux: Sedimentation (CF:CS) and Rate of Supply (CRS) unsupported⧸excess 210Pb models have been applied to a data set providing eighteen sediments profiles sampled at four riverine systems occurring in Brazil, South America: Corumbatai River basin (S1=Site 1, Sao Paulo State), Atibaia (S2=Site 2, Ribeirao dos Bagres (S3=Site 3, State) Amazon mouth (S4=Site 4, Amapa State). These sites were chosen for comparative evaluation the performance CF:CS CRS due their pronounced differences on geographical location, geological context, soil composition, biodiversity, climate, rainfall, water flow regime, among other variable aspects. However, all cores exhibited common denominator consisting database built from use same techniques acquiring major chemical composition (SiO2, Al2O3, Na2O, K2O, CaO, MgO, Fe2O3, MnO, P2O5, TiO2 LOI-Loss Ignition) activity data. In terms sedimentation rates, model was better than that as it yielded values more compatible with those expected field evidences. Under chronological point view, always provided ages within permitted range 210Pb-method studied sites, whereas predicted some above 150 years. SiO2 content decreased accordance LOI increase analyzed such inverse relationship also tracked SiO2–LOI curves historical trends. concentration fluctuations S1 S3 coincided Cu Cr inputs drainage systems.