Lithological maps have been proved to be a useful tool to evaluate regional and global matter fluxes from chemical weathering. However, lithological classes provide aggregated information of mineralogical, geochemical, sedimentary or diagenetic properties. Thus, using a limited number of lithological classes introduces by their definition a bias to the analysis of weathering fluxes, specifically in the case of multilithological catchments. Here it is shown that the coupling of geochemical with lithological information may help to better identify the sources of the weathering fluxes, using the example of dissolved Ca to better distinguish weathering rates of silicate and non-silicate minerals. (C) 2011 Elsevier Ltd. All rights reserved.