EVIDENCE FOR MUON-INDUCED PRODUCTION OF BE-10 IN NEAR-SURFACE ROCKS FROM THE CONGO

Distributions of Be-10 in vein quartz from a lateritic weathering profile from the Congo provide evidence for significant in situ production of Be-10 by reactions other than neutron-induced spallation. After consideration of geomorphological and nuclear processes which might contribute to the observed depth variability, we conclude that cosmic ray muon-induced reactions are the most likely mechanism, and that such reactions lead to 1% to 3% of Be-10 production at the surface. This small muon-induced component has only minor implications for the use of Be-10 for quantification of exposure histories of surficial rocks. Nevertheless, the muogenic component has the potential to expand the utility of cosmogenic nuclides in examination of surficial processes, overcoming some of the limitations associated with the use of the neutron-produced component.