Geodynamic environment of Quaternary morphostructures of the subandean foreland basins of Peru and Bolivia: Characteristics and study methods

The Quaternary evolution of western Amazon basins is considered using morphostructural analysis of fluvial belts and lakes. Meandering rivers from the basin surface are analyzed using three scales of elements: the ridge and swale pattern, the mosaic pattern and the fluvial belt. Lake patterns are differentiated according to their shape, the hydrological environment and the structural context. Influences of basement structures and neotectonic deformations, when known, are considered. The morphostructural patterns are discussed in the context of a balance of internal (tectonic) and external (hydraulic and sedimentologic) processes. Special attention is focussed on the effect of neotectonics, which is generally neglected, on the formation and the location of Quaternary morphostructures. The adaptation of study methods and sampling to the characteristics of the different morphostructures is considered.