Comparison between Silicate Weathering and Physical Erosion Rates in Andean Basins of the Amazon River ?

International audienceFrom published data based on the HYBAM observatory database, we explore the relationship between silicate weathering rates and physical erosion rates over the Andean basins of the Amazon River. No homogenous relationship between erosion rates and chemical weathering rate is observed over this area. Only the volcanic basins respond to the global relationship defined by Millot et al1. For remaining areas, two hypotheses can explain the absence of coherence with this global empiric law: 1) The relationship between weathering and physical erosion rates need to be defined for each lithological class, and 2) For erosion rates higher than around 1000t.km-2.yr-1 the system is "weathering limited"