DENUDATION RATES DETERMINED FROM THE ACCUMULATION OF IN SITU-PRODUCED BE-10 IN THE LUQUILLO EXPERIMENTAL FOREST, PUERTO-RICO

We present a simple method for estimation of long-term mean denudation rates using in situ-produced cosmogenic Be-10 in fluvial sediments. Procedures are discussed to account for the effects of soil bioturbation, mass wasting and attenuation of cosmic rays by biomass and by local topography. Our analyses of Be-10 in quartz from bedrock outcrops, soils, mass-wasting sites and riverine sediment from the Icacos River basin in the Luquillo Experimental Forest, Puerto Rico, are used to characterize denudation for major landform elements in that basin. The Be-10 concentration of a discharge-weighted average of size classes of river sediment corresponds to a long-term average denudation of approximate to 43 m Ma(-1), consistent with mass balance results.