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 prof ile from the Congo provide evidence for significant in situ production of Be-10 by reactions other than neutron-induced spallation. After co nsideration of geomorphological and nuclear processes which might cont ribute to the observed depth variability, we conclude that cosmic ray muon-induced reactions are the most likely mechanism, and that such re actions lead to 1% to 3% of Be-10 production at the surface. This smal l muon-induced component has only minor implications for the use of Be -10 for quantification of exposure histories of surficial rocks. Never theless, the muogenic component has the potential to expand the utilit y of cosmogenic nuclides in examination of surficial processes, overco ming some of the limitations associated with the use of the neutron-pr oduced component.