Denudation rates of the Quadrilatero Ferrifero (Minas Gerais, Brazil): preliminary results from measurements of solute fluxes in rivers and in situ-produced cosmogenic Be-10

This paper investigates the denudation rates in the Quadrilatero Ferrifero, Minas Gerais State (Brazil). The aim is to compare chemical weathering rates from measurements of solute fluxes in rivers and long-term mean erosion rates deduced from in situ-produced cosmogenic Be-10 concentrations measured in fluvial sediments. Both water samples and sediments were collected in fifteen stations (checkpoints) located in four hydrographic basins with low anthropogenic perturbations. Depending of the type of substratum, three degrees of chemical denudation rates from water samples are observed: (i) high rates in marbles; (ii) medium rates in schists, phyllites, granites, gneisses and migmatites; (iii) low rates in quartzites and itabirites. Preliminary results of long-term erosion rates deduced from in situ-produced Be-10 are comparable with those of chemical rates. (c) 2005 Elsevier B.V. All rights reserved