Characterisation of river bed and suspended sediments in the Rio Madeira drainage basin (Bolivian Amazonia)

The grain size distribution of river bed sediments in the Rio Madeira drainage basin shows rapid deposition of the coarser material (greater than 10 mm) as the river flows out of the Andean range to enter the Amazon plain (Llanos). In the Andes, the suspended sediment grain size varies between 0.02 and 0.10 mm in diameter, while in the Llanos the suspended load is dominated by fine silts, between 7 and 7 micrometers in diameter. In the Llanos, neither the bed sediment nor the suspended sediment varied along a 800 km reach. (Résumé d'auteur)